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Case Studies

A 32-year-old body builder has decided to go on a diet consisting of egg whites to ensure only proteins for muscle growth. After a few weeks he experiences decreased energy and is found to be hypoglycemic. A nutritionist tells the patient that he most likely has the deficiency of vitamin Biotin. Which of the following enzymes is unable to catalyze its step in synthesizing glucose from pyruvate?

A) Pyruvate carboxylase

B) Phospho enol pyruvate carboxykinase

C) Glucose-6-phosphatase

D) Fructose 1, 6 bisphosphatase

E) Phosphoglycerate kinase.

The correct answer is- A) – Pyruvate carboxylase.

Biotin deficiency is very common in bodybuilders, who consume raw egg whites. The Raw egg whites contain Avidin, a glycoprotein that strongly binds with biotin and prevents its absorption. Once a biotin-Avidin complex forms, the bond is essentially irreversible; the biotin-Avidin complex is not broken during passage of the food bolus through the stomach and intestines. As a result, biotin is not liberated from food, and the biotin-Avidin complex is lost in the feces. Thus, the ingestion of large quantities of raw egg white over a long period can result in a biotin deficiency. Cooking egg white denatures Avidin, rendering it susceptible to digestion and therefore unable to prevent the absorption of dietary biotin.

Biotin functions to transfer carbon dioxide in a small number of carboxylation reactions. Biotin is attached at the active site of carboxylases.

Each Biotin dependent carboxylase catalyzes an essential metabolic reaction:

1) Pyruvate carboxylase

Pyruvate carboxylase is a critical enzyme in gluconeogenesis—the formation of glucose from sources other than carbohydrates, for example, amino acids. Oxaloacetate formed from pyruvate can be utilized in many other ways depending upon the need of the cell (Figure-3)

Reaction catalyzed by pyruvate carboxylase

Figure-1 -Carboxylation of pyruvate to Oxaloacetate, catalyzed by Pyruvate carboxylase, is the first step of gluconeogenesis.

The other examples where Biotin is required as a coenzyme are:

2) Acetyl-CoA carboxylase (ACC) catalyzes the binding of bicarbonate to acetyl-CoA to form malonyl-CoA (Figure-2). Malonyl-CoA is required for the synthesis of fatty acids.

Reaction-catalyzed-by-Acetyl-co-A-carboxylase

Figure-2 -The carboxylation of Acetyl co A to form Malonyl co A, catalyzed by Acetyl co A carboxylase is the first and the rate limiting step in fatty acid synthesis.

3) Propionyl-CoA carboxylase catalyzes essential steps in the metabolism of certain amino acids, cholesterol, and odd chain fatty acids (fatty acids with an odd number of carbon molecules).

Fate of propionyl co A

Figure- 3-showing the fate of Propionyl co A

Propionyl co A is converted first to D- Methyl malonyl co A and then to its L isomer, ultimately to succinyl co A for complete utilization in the TCA cycle (Figure-3).

Anaplerotic reactions catalyzed by biotin dependent pyruvate carboxylase (PC) and Propionyl-coenzyme A carboxylase (PCC) regenerate oxaloacetate for the citric acid cycle.

As regards other options

B) Phospho enol pyruvate carboxykinase- Catalyzes the conversion of Oxaloacetate to phosphoenol pyruvate, it is an enzyme of pathway of gluconeogenesis but it is not a biotin dependent enzyme

C) Glucose-6-phosphatase catalyzes the last step of conversion of glucose-6-Phosphate to free glucose, but it is also not biotin dependent enzyme.

D) Fructose 1, 6 bisphosphatase- catalyzes the conversion of fructose1, 6 bisphosphate to Fructose 6 Phosphate; it is also not a biotin dependent enzyme.

E) Phosphoglycerate kinase- is a common enzyme, both for the pathways of glycolysis and gluconeogenesis. It catalyzes the reversible conversion of 1, 3 bisphosphoglycerate to 3, phosphoglycerate, ATP is formed by substrate level phosphorylation in glycolysis. ATP is consumed in the reverse reaction, in the pathway of gluconeogenesis.

 

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Case details

A 4 -year-old boy was brought for consultation for hematuria, edema of lower extremities as well as swollen right leg. He was the 12th born in a poor family, where one previous child died from malnutrition and dehydration in the period of infancy. The child was fed only with cow’s milk and biscuits. From the period of five months, the boy manifested irritability, sweating, poor appetite and cried when somebody touched him

At admission the baby was afebrile, pale, and malnourished. Clinical evaluation showed no organomegaly, no neurological signs, gingival bleeding was there and only one tooth was present. The child was diagnosed with ‘Scurvy’, which is a clinical sate of severe vitamin C deficiency. Vitamin C has an important role in the body, besides performing multiple functions, and acting as an antioxidant, it is also required as a coenzyme for specific reactions.

Which ‘one’ of the following conversions is inhibited in scurvy?

A. Conversion of Pyruvate to Acetyl co A

B. Conversion of Propionyl co A to succinyl co A

C. Conversion of Homocysteine to Methionine

D. Conversion of Proline to Hydroxyproline

E. Conversion of Succinate to fumarate.

The correct answer is D- Conversion of Proline to Hydroxyproline.

Basic concept

Vitamin C dependent Proline and lysine hydroxylases are required for the postsynthetic modification of procollagen to collagen. The proline to hydroxyproline conversion reaction can be represented as follows:

 Hydroxylation of Proline

Figure- Hydroxylation of proline is an essential prerequisite for collagen synthesis. The hydroxylation of Lysine is also carried out in the same manner.

Deficiency of vitamin C leads to impaired collagen synthesis, causing capillary fragility, poor wound healing, and bony abnormalities in affected adults and children.

The functions of vitamin C can be summarized alphabetically as follows:

A) It is an antioxidant and is also required for the amino acid metabolism such as metabolism of tryptophan and tyrosine.

B) Vitamin C is required for Bone formation, Bile acid synthesis and Brain function

C) It is required for the synthesis of Collagen, Carnitine, Complement and Catecholamines.

D) Drug detoxification- It is a component of many drug-metabolizing enzyme systems, particularly the mixed-function oxidase systems.

E) Enzymes– Vitamin C is the coenzyme for two groups of hydroxylases. These are copper-containing hydroxylases and the α-ketoglutarate-linked iron-containing hydroxylases. 

F) Folic acid metabolism- Ascorbic acid is required for reducing Folic acid to its tetrahydrofolate form. Thus it helps in the maturation of red blood cells.

G) General body growth- Vitamin C has a protective role and because of its role in disease prevention, it stimulates general body growth.

H) Vitamin C is helpful in the reconversion of met haemoglobin to haemoglobin. Vitamin C is also a cofactor in the synthesis of peptide hormones, corticosteroids, and aldosterone.

I) The vitamin C has an important role in the absorption and conversion of Iron to its storage form. This may contribute to the anemia seen with vitamin C deficiency.

Vitamin C promotes Immunity and has been proposed to have pharmacological benefits in preventing cancer, infections, and the common cold.

As regards other options

A. Conversion of Pyruvate to Acetyl co A- requires Thiamine (TPP), Pantothenic acid (CoASH), Lipoic acid, FAD and NAD + as coenzymes. The reaction is catalyzed by Pyruvate dehydrogenase complex, which is a multienzyme complex.

B. Conversion of Propionyl co A to succinyl co A is a multistep process. Biotin and vitamin B12 are required for the metabolism of Propionyl co A.

C. Conversion of Homocysteine to Methionine- requires the presence of Methylcobalamine and folic acid, the reaction is catalyzed by Methionine synthase.

E. Conversion of Succinate to fumarate- is catalyzed by succinate dehydrogenase; the enzyme requires the presence of FAD (Riboflavin) for its action.

Thus in vitamin C deficiency, the conversion of proline to hydroxyproline is inhibited.

For further reading

Check the following links

Functions of Vitamin C

http://www.namrata.co/a-to-i-of-vitamin-c-functions-of-vitamin-c-simplified/

Vitamin C deficiency

http://www.slideshare.net/namarta28/vitamin-c-deficiency

 

 

 

 

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A postoperative patient on intravenous fluids develops lesions in the mouth (angular stomatitis). Urinalysis indicates an excretion of 15 μg riboflavin/mg creatinine, which is abnormally low. Which of the following TCA cycle enzymes is most likely to be affected?

A. Citrate synthase

B. Isocitrate dehydrogenase

C. Fumarase

D. Malate dehydrogenase

E. Succinate dehydrogenase

Details– E) – Succinate dehydrogenase is the correct answer.

The patient has demonstrated a deficiency in riboflavin (urinary excretion of less than 30 μg/mg creatinine is considered clinically deficient). Vitamin B2 deficiency is frequent in chronic alcoholics.  It can also occur in patients with chronic liver diseases, and in hospitalized patients who receive total parenteral nutrition (TPN) with inadequate riboflavin supplementation. Riboflavin is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin supports energy production by aiding in the metabolism of fats, carbohydrates, and proteins . Characteristic symptoms of riboflavin deficiency include lesions of the skin, especially in the corners of the mouth (angular stomatitis) and a red, sore fissured tongue (figure-1).

 Angular stomatitis

Figure-1- Angular stomatitis

Riboflavin functions in several different enzyme systems. Two derivatives, riboflavin 5′ phosphate (flavin mononucleotide [FMN]) and riboflavin 5′ adenosine diphosphate (flavin adenine dinucleotide [FAD]), are the coenzymes that unite with specific apoenzyme proteins to form flavoprotein enzymes.

 Structure of Riboflavin

Figure-2- Structure of Riboflavin. It contains D- ribitol, and the Isoalloxazine ring( flavin nucleus)

FMN and FAD function as coenzymes for a wide variety of oxidative enzymes and remain bound to the enzymes during the oxidation-reduction reactions. Flavins can act as oxidizing agents because of their ability to accept a pair of hydrogen atoms. Reduction of isoalloxazine ring (FAD, FMN oxidized form) yields the reduced forms of the flavoprotein (FMNH2 and FADH2).

Enzymes that contain flavin adenine dinucleotide (FAD) or flavin-mononucleotide (FMN) as prosthetic groups are known as flavoenzymes.

Succinate dehydrogenase is the only FAD dependent enzyme in TCA cycle. Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction catalyzed can be represented as follows

 Succinate dehydrogenase

Figure-3- Reaction catalyzed by succinate dehydrogenase

As regards other options

Citrate synthase catalyzes the condensation of acetyl co A and oxaloacetate to form Citrate (Figure-4); it does not require FMN or FAD as a coenzyme.

 TCA cycle

Figure-4- TCA cycle enzymes and the steps of TCA cycle. (IDH is isocitrate dehydrogenase)

Isocitrate and malate dehydrogenase are NAD + dependent enzymes.

Fumarase catalyzes the conversion of Fumarate to malate; it also does not require riboflavin as a coenzyme.

Thus out of all the given options, Succinate dehydrogenase is the only TCA cycle enzyme, the activity of which can be affected in riboflavin deficiency.

 

 

 

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Case details –A 44-year-old man who had lost his job because of absenteeism, presented to his physician complaining of loss of appetite, fatigue, muscle weakness, and emotional depression.

The physical examination revealed a somewhat enlarged liver that was firm and nodular, and there was a hint of jaundice in the sclerae and a hint of alcohol in his breath. The initial laboratory profile included a hematological analysis that showed that he had an anemia with enlarged red blood cells (macrocytic). A bone marrow aspirate confirmed the suspicion that he had a megaloblastic anemia because it showed a greater than normal number of red and white blood cell precursors, most of which were larger than normal. Further analyses revealed that his serum folic acid level was1.2 ng/mL (normal 2.5 to20), his serum B12 level was 253 ng/mL (normal 200 to 900), but his serum iron level was normal.

What is the cause of megaloblastic anemia in this patient? What is its correlation with alcoholism?

Case discussion –The megaloblastic anemias are a group of disorders characterized by the presence of distinctive morphological appearances of the developing red cells in the bone marrow. The cause is usually deficiency of either cobalamin (vitamin B12) or folate, but megaloblastic anemia may arise because of genetic or acquired abnormalities affecting the metabolism of these vitamins or because of defects in DNA synthesis not related to cobalamin or folate. Megaloblastic anemia in folate deficiency is identical to anemia resulting from vitamin B12 deficiency However, the serum vitamin B12 level is normal in this patient so that rules out vitamin B12 deficiency. Alcoholics in particular are at risk for folate deficiency because of impaired gastrointestinal absorption and poor nutrition. Folate is essential for many biochemical processes in the body, including DNA synthesis and red blood cell synthesis. 

Megaloblastic anemia due to folate deficiency

Incidence

The current standard of practice is that serum folate levels less than 3 ng/mL and a red blood cell (RBC) folate level less than 140 ng/mL puts an individual at high risk of folate deficiency. The RBC folate level generally indicates folate stored in the body, whereas the serum folate level tends to reflect acute changes in folate intake. The prevalence of folic acid deficiency has decreased since the United States and Canada introduced a mandatory folic acid food fortification program in November 1998. People with excessive alcohol intake and malnutrition are still at high risk of folic acid deficiency.

Biochemical Basis of Megaloblastic Anemia

The common feature of all megaloblastic anemias is a defect in DNA synthesis that affects rapidly dividing cells in the bone marrow. All conditions that give rise to megaloblastic changes share in common a disparity in the rate of synthesis or availability of the four immediate precursors of DNA: the deoxyribonucleoside triphosphates (dNTPs): dA(adenine)TP and dG(guanine)TP (purines), dT(thymine)TP and dC(cytosine)TP (pyrimidines). In deficiencies of either folate or cobalamin, there is failure to convert deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate (dTMP), the precursor of dTTP. This is because folate is needed as the coenzyme 5, 10-methylene-THF polyglutamate for conversion of dUMP to dTMP; the availability of 5, 10-methylene-THF is reduced in either cobalamin or folate deficiency (Figure-1).

Cobalamin-Folate Relations

Folate is required for many reactions in mammalian tissues. Only two reactions in the body are known to require cobalamin. Methylmalonyl CoA isomerization, which requires Adenosyl cobalamin and the methylation of homocysteine to methionine, requires both methylcobalamin and both 5-MTHF. In cobalamin deficiency, MTHF accumulates in plasma, while intracellular folate concentrations fall due to failure of formation of THF, the substrate on which folate polyglutamates are built. This has been termed THF starvation, or the methylfolate trap (Figure-1) .This theory explains the abnormalities of folate metabolism that occur in cobalamin deficiency and also why the anemia of cobalamin deficiency will respond to folic acid in large doses.

Figure-1 showing the role of folic acid in DNA synthesis and methionine metabolism

Causes of folate deficiency

Folate deficiency can result from several possible causes, including inadequate ingestion, impaired absorption, impaired metabolism leading to inability to utilize folate that is absorbed, increased requirement, increased excretion, and increased destruction.

  • Inadequate ingestion of folate-containing foods: Poor nutrition is prevalent among people with alcoholism and patients with psychiatric morbidities, as well as elderly people (due to conditions such as ill-fitting dentures, physical disabilities, and social isolation). Because folates are destroyed by prolonged exposure to heat, people of certain cultures that involve traditionally cooking food in kettles of boiling water may be predisposed to folate deficiency. Moreover, for patients with renal and liver failure, anorexia and restriction of foods rich in protein, potassium, and phosphate contribute to decreased folate intake.
  • Impaired absorption
    • The limiting factor in folate absorption is its transport across the intestinal wall. Folate transport across the gut wall mainly is carrier mediated saturable, substrate specific, pH dependent (optimal at low pH), sodium dependent, and susceptible to metabolic inhibitors. Passive, diffusional absorption also occurs, to a minor degree. A decreased absorptive area due to small bowel resection or mesenteric vascular insufficiency would decrease folate absorption.
    • Celiac disease and tropical sprue cause villous atrophy. The process of aging causes shorter and broader villi in 25% of the elderly population. Achorhydria leads to elevation of gastric pH above the optimal level (ie, pH of 5) for folate absorption. Anticonvulsant drugs, such as Dilantin, interfere with mucosal conjugase, hence impairing folate absorption. Zinc deficiency also decreases folate absorption because zinc is required to activate mucosal conjugase. Bacterial overgrowth in blind loops, stricture formation, or jejunal diverticula likewise would decrease folate absorption.
  • Impaired metabolism, leading to inability to utilize absorbed folate: Antimetabolites that are structurally analogous to the folate molecule can competitively antagonize folate utilization. Methotrexate and trimethoprim both are folate antagonists that inhibit dihydrofolate reductase. Hypothyroidism has been known to decrease hepatic levels of dihydrofolate reductase as well as Methylene THFA reductase. Furthermore, congenital deficiency involving the enzymes of folate metabolism also can show impaired folate utilization. People with alcoholism can have very active alcohol dehydrogenase that binds up folate and thus interferes with folate with folate utilization.
  • Increased requirement: Factors that increase the metabolic rate can increase the folic requirement. Infancy (a period of rapid growth), pregnancy (rapid fetal growth), lactation (uptake of folate into breast milk), malignancy (increased cell turnover), concurrent infection (Immuno proliferative response), and chronic hemolytic anemia (increased hematopoiesis) all can result in an increased folate requirement.
  • Increased excretion/loss: Increased excretion of folate can occur subsequent to vitamin B-12 deficiency. During the course of vitamin B-12 deficiency, methylene THFA is known to accumulate in the serum, which is known as the folate trap phenomenon. In turn, large amounts of folate filter through the glomerulus, and urine excretion occurs.
  • Increased destruction: Superoxide, an active metabolite of ethanol metabolism, is known to inactivate folate by splitting the folate molecule in half between the C9 and N10 position. The relationship between cigarette smoking and low folate levels has been noted as possibly due to folate inactivation in exposed tissue.

Clinical manifestations

  1. History- In folate deficiency, the patient’s history is important because it may reveal the underlying disorder. Very often, a patient presents with a history of excessive alcohol intake with concurrent poor diet intake. Other times, patients may be pregnant or lactating; may take certain drugs, such as phenytoin, sulfonamides, or methotrexate; may have chronic hemolytic anemia; or may have underlying malabsorption.
  2. Oral lesions –Some patients complain of a sore tongue or pain upon swallowing. The tongue may appear swollen, beefy, red, or shiny, usually around the edges and tips initially (Figure-2). Angular stomatitis also may be observed (Figure-3).These oral lesions typically occur at the time when folate depletion is severe enough to cause megaloblastic anemia, although, occasionally, lesions may occur before the anemia.
  3.  GI symptoms –Patients may present with GI symptoms, such as nausea, vomiting, abdominal pain, and diarrhea, especially after meals. Anorexia also is common and, in combination with the above symptoms, may lead to marked weight loss. However,  an underlying malabsorption disorder could be causing these symptoms, as well as folate depletion. The lack of folate itself may not be the culprit.
  4. Hyper pigmentation-Patients with folate deficiency may have darkening of the skin and mucous membranes, particularly at the dorsal surfaces of the fingers, toes, and creases of palms and soles. Distribution typically is patchy. Fortunately, the hyperpigmentation gradually should resolve after weeks or months of folate treatment. A modest temperature elevation (<102°F) is common in patients who are folate deficient, despite the absence of any infection. Although the underlying mechanism is obscure, the temperature typically falls within 24-48 hours of vitamin treatment and returns to normal within a few days.
  5. Hematological manifestations– Folate deficiency can cause anemia. The presentation typically consists of macrocytosis and hyper segmented polymorph nuclear leucocytes (PMNs). The anemia usually progresses over several months, and the patient typically does not express symptoms as such until the hematocrit level reaches less than 20%. At that point, symptoms such as weakness, fatigue, difficulty concentrating, irritability, headache, palpitations, and shortness of breath can occur. Furthermore, heart failure can develop in light of high-output cardiac compensation for the decreased tissue oxygenation. Angina pectoris may occur in predisposed individuals due to increased cardiac work demand. Tachycardia, postural hypotension, and lactic acidosis are other common findings. Less commonly, neutropenia and thrombocytopenia also will occur, although it usually will not be as severe as the anemia. In rare cases, the absolute neutrophil count can drop below 1000/mL and the platelet count below 50,000/mL.

 Figure-2- Glossitis in folic acid deficiency

 Figure-3- Angular stomatitis in folic acid deficiency

Laboratory Investigations

  • Serum folate (reference range 2.5-20 ng/mL) and serum cobalamin (reference range 200-900 pg/mL)
    • As the initial test, ruling out cobalamin deficiency is very important because folate treatment will not improve neurologic abnormalities due to cobalamin deficiency.
    • Additional follow-up tests include serum homocysteine (reference range 5-16 mmol/L), which is elevated in B-12 and folate deficiency, and serum methylmalonic acid (reference range 70-270 mmol/L), which is elevated in B-12 deficiency only.
    • Red blood cell folate levels (reference range >140 ng/mL) tend to reflect chronic folate status rather than acute changes in folate that are reflected in serum folate levels,
  • Hematological Findings (Peripheral Blood film)

Oval macrocytes, usually with considerable anisocytosis and poikilocytosis, are the main feature (Figure-4).The MCV is usually >100 fL unless a cause of microcytosis (e.g., iron deficiency or thalassemia trait) is present. Some of the neutrophils are hyper segmented (more than five nuclear lobes). There may be leucopenia due to a reduction in granulocytes and lymphocytes, but this is usually >1.5 x 109/L; the platelet count may be moderately reduced, rarely to <40 x 109/L. The severity of all these changes parallels the degree of anemia. In the nonanemic patient, the presence of a few macrocytes and hyper segmented neutrophils in the peripheral blood may be the only indication of the underlying disorder.

Figure – 4 – showing peripheral blood film in megaloblastic anemia. Macrocytes are observed and some of the red blood cells show ovalocytosis. A 6-lobed polymorph nuclear leucocyte is present.

  • Bone Marrow

Bone marrow morphology is characteristically abnormal . Marked erythroid hyperplasia is present as a response to defective red blood cell production (ineffective erythropoiesis). Megaloblastic changes in the erythroid series include abnormally large cell size and asynchronous maturation of the nucleus and cytoplasm—ie, cytoplasmic maturation continues while impaired DNA synthesis causes retarded nuclear development. In the myeloid series, giant metamyelocytes are characteristically seen.

  • Ineffective Hematopoiesis- There is an accumulation of unconjugated bilirubin in plasma due to the death of nucleated red cells in the marrow (ineffective erythropoiesis). Other evidence for this includes raised urine urobilinogen, reduced Haptoglobin and positive urine Haemosiderin, and a raised serum lactate dehydrogenase. A weakly positive direct antiglobulin test due to complement can lead to a false diagnosis of autoimmune hemolytic anemia.

Mortality/Morbidity

Elevated serum homocysteine and atherosclerosis

Folate in the 5-methyl THFA form is a cosubstrate required by methionine synthase when it converts homocysteine to methionine. As a result, in the scenario of folate deficiency, homocysteine accumulates. Several recent clinical studies have indicated that mild-to-moderate hyperhomocysteinemia is highly associated with atherosclerotic vascular disease such as coronary artery disease (CAD) and stroke. In this case, mild hyperhomocysteinemia is defined as total plasma concentration of 15-25 mmol/L and moderate hyperhomocysteinemia is defined as 26-50 mmol/L.

Elevated homocysteine levels might act as an atherogenic factor by converting a stable plaque into an unstable, potentially occlusive, lesion. Homocysteine is believed to have atherogenic and prothrombotic properties via multiple mechanisms.
Pregnancy complications

Possible pregnancy complications secondary to maternal folate status may include spontaneous abortion, abruption placentae, and congenital malformations (eg, neural tube defect).

Although the exact mechanism is not understood, a relative folate shortage may exacerbate an underlying genetic predisposition to neural tube defects.

Effects on carcinogens

Diminished folate status is associated with enhanced carcinogenesis.

Effects on cognitive function

Low folate and high homocysteine levels are a risk factor for cognitive decline in high-functioning older adults and high homocysteine level is an independent predictor of cognitive impairment among long-term stay geriatric patients.

Mechanistically speaking, current theory proposes that folate is essential for synthesis of S- adenosylmethionine, which is involved in numerous methylation reactions. This methylation process is central to the biochemical basis of proper neuropsychiatric functioning.

Treatment

Fruits and vegetables constitute the primary dietary source of folic acid. The minimal daily requirement is about 50 mcg, but this may be increased several fold during periods of enhanced metabolic demand such as pregnancy.

Recommended Daily Allowance

Males: 400 mcg/d

Females: 400 mcg/d

Pregnant: 600 mcg/d

Nursing: 500 mcg/d

Deficiency treatment

0.4-1 mg per day. Large  doses of 5–15 mg folic acid daily are given in patients with severe absorption. It is essential to exclude cobalamin deficiency before large doses of folic acid are given, and deficiency if present must be corrected, otherwise cobalamin neuropathy may develop, despite a response of the anemia of cobalamin deficiency to folate therapy.

Prevention- Patients whose folic acid deficiency is related to dietary factors should be counseled to include green vegetables and fruit in their diet. Prophylactic treatment of pregnant patients and patients with chronic hemolytic anemias can prevent folic acid deficiency due to the increased requirement for folate in these conditions.

Supplements and food fortification

Folic acid is added to a variety of foods, the most important of which are flour, salt, breakfast cereals and beverages, soft drinks and baby foods. Folic acid is available as oral preparations, alone or in combination with other vitamins or minerals (e.g. iron), and as an aqueous solution for injection. As folic  acid is only poorly soluble in water, folate salts are used to prepare liquid dosage forms. Folinic acid (also known as leucovorin or citrovorum factor) is a derivative of folic acid administered by intramuscular injection to circumvent the action of dihydrofolate reductase inhibitors, such as methotrexate. It is not otherwise indicated for the prevention or treatment of folic acid deficiency. 

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Case details

A 20-year-old female was brought to the emergency department with respiratory distress. She gave a history of fever from the previous few days. She was a known alcoholic but used to take alcohol only during episodes of depression.

On examination she was pale, malnourished, agitated and acutely ill. She was in acute respiratory distress. Her pulse was 110/ minute, there was marked tachycardia and a systolic murmur was heard along the left sternal edge. Bilateral crepitations were felt in the lungs, Neck veins were engorged and liver was also enlarged, although non tender. Bilateral foot drop was also there.

What is the probable diagnosis?

What kind of investigations should be carried out to confirm the diagnosis ?

 

Case discussion

The patient is most probably suffering from cardiac beriberi. The criteria for diagnosing cardiac beriberi is-

1)  Signs of heart failure

2) signs of neuropathies

3) history of alcoholism or poor nutritional history,

4) exclusion of other signs of heart failure,

5) low red cell transketolase activity

6) Response by thiamine administration.

The above said patient is a known alcoholic, mal nourished, has heart failure and bilateral foot drop. The probable diagnosis is Thiamine deficiency, that  can be confirmed by erythrocyte transketolase activity.

Thiamine deficiency (causing beriberi) is most common among people subsisting on white rice or highly refined carbohydrates in developing countries and among alcoholics. Symptoms include diffuse polyneuropathy, high-output heart failure, and Wernicke-Korsakoff syndrome. Thiamine is given to help diagnose and treat the deficiency.

Basic concept

Thiamine

Thiamine (vitamin B1) is widely available in the diet. Thiamine is involved in carbohydrate, fat, amino acid, glucose, and alcohol metabolism. It is essentially nontoxic. The body cannot produce it and can only store up to 30 mg of thiamine in its tissues. Thiamine is mostly concentrated in the skeletal muscles. Other organs where it is found are the brain, heart, liver and kidneys. The half-life of thiamine is 9-18 days. It is excreted by the kidney.

Pathophysiology of Thiamine deficiency (Beri-Beri)

Deficiency causes degeneration of peripheral nerves, thalamus, mammillary bodies, and cerebellum. Cerebral blood flow is markedly reduced, and vascular resistance is increased.

The heart may become dilated; muscle fibers become swollen, fragmented, and vacuolized, with interstitial spaces dilated by fluid. Vasodilation occurs and can result in edema in the feet and legs. Arteriovenous shunting of blood increases. Eventually, high-output heart failure may occur.

Dry beriberi Nervous system involvement is termed dry beriberi.The neurologic findings can be peripheral neuropathy characterized by symmetric impairment of sensory, motor, and reflex functions of the extremities, especially in the distal lower limbs. Another presentation of neurologic involvement is Wernicke’s encephalopathy, in which an orderly sequence of symptoms occurs, including vomiting, horizontal nystagmus, palsies of the eye movements, fever, ataxia, and progressive mental impairment leading to Korsakoff syndrome.

Wet beriberi is the term used for the cardiovascular involvement of thiamine deficiency. The chronic form of wet beriberi consists of 3 stages. In the first stage, peripheral vasodilation occurs, leading to a high cardiac output state. This leads to salt and water retention mediated through the renin-angiotensin-aldosterone system in the kidneys. As the vasodilation progresses, the kidneys detect a relative loss of volume and respond by conserving salt. With the salt retention, fluid is also absorbed into the circulatory system. The resulting fluid overload leads to edema of the dependent extremities.

Figure- showing edema of the lower extremity.

By the time significant edema occurs, the heart has been exposed to a severely high workload in order to pump the required cardiac output needed to satisfy end organ requirements. Parts of the heart muscle undergo overuse injury, which results in the physical symptoms of tachycardia, edema, and high arterial and venous pressures. These changes can lead to myocardial injury, expressed as chest pain.

Shoshin beriberi A more rapid form of wet beriberi is termed acute fulminant cardiovascular beriberi, or Shoshin beriberi. The predominant injury is to the heart, and rapid deterioration follows the inability of the heart muscle to satisfy the body’s demands because of its own injury. In this case, edema may not be present. Instead, cyanosis of the hands and feet, tachycardia, distended neck veins, restlessness, and anxiety occur.

Infantile beriberi occurs in infants (usually by age 3 to 4 wk) who are breastfed by thiamine-deficient mothers.

Frequency

Beriberi is observed in developed nations in persons with alcoholism, people on fad diets, persons on long-term peritoneal dialysis without thiamine replacement, persons undergoing long-term starvation, or persons receiving intravenous fluids with high glucose concentration. No accurate statistics are available on the incidence of this condition.

Clinical Manifestations

Early symptoms are nonspecific: fatigue, irritability, poor memory, sleep disturbances, precordial pain, anorexia, and abdominal discomfort.

Dry beriberi refers to peripheral neurologic deficits due to thiamine deficiency. These deficits are bilateral and roughly symmetric, occurring in a stocking-glove distribution. They affect predominantly the lower extremities, beginning with paresthesias in the toes, burning in the feet (particularly severe at night), muscle cramps in the calves, pains in the legs, and plantar dysesthesias. Calf muscle tenderness, difficulty rising from a squatting position, and decreased vibratory sensation in the toes are early signs. Muscle wasting occurs. Continued deficiency worsens polyneuropathy, which can eventually affect the arms.

Wernicke-Korsakoff syndrome, which combines Wernicke’s encephalopathy and Korsakoff’s psychosis occurs in some alcoholics who do not consume foods fortified with thiamine. Wernicke’s encephalopathy consists of psychomotor slowing or apathy, nystagmus, ataxia, ophthalmoplegia, impaired consciousness, and, if untreated, coma and death. It probably results from severe acute deficiency superimposed on chronic deficiency. Korsakoff psychosis consists of mental confusion, dysphonia, and confabulation with impaired memory of recent events. It probably results from chronic deficiency and may develop after repeated episodes of Wernicke’s encephalopathy.

Cardiovascular (wet) beriberi is myocardial disease due to thiamine deficiency. The first effects are vasodilation, tachycardia, a wide pulse pressure, sweating, warm skin, and lactic acidosis. Later, heart failure develops, causing orthopnea and pulmonary and peripheral edema. Vasodilation can continue, sometimes resulting in shock.

Infantile beriberi– Heart failure (which may occur suddenly), aphonia, and absent deep tendon reflexes are characteristic.

Because thiamine is necessary for glucose metabolism, glucose infusions may precipitate or worsen symptoms of deficiency in thiamine-deficient people.

Causes

  • Lack of thiamine intake
    • Diets consisting mainly of the following:
      • Food containing a high level of thiaminase, including milled rice, raw freshwater fish, raw shellfish, and ferns
      • Food high in anti-thiamine factor, such as tea, coffee, and betel nuts
      • Processed food with a content high in sulfite, which destroys thiamine
    • Alcoholic state
    • Starvation state
  • Increased consumption states
    • Diets high in carbohydrate or saturated fat intake
    • Pregnancy
    • Hyperthyroidism
    • Lactation
    • Fever – severe infection
    • Increased physical exercise
  • Increased depletion
    • Diarrhea
    • Diuretic therapies
    • Peritoneal dialysis
    • Hemodialysis
    • Hyperemesis gravidarum
  • Decreased absorption
    • Chronic intestinal disease
    • Alcoholism
    • Malnutrition
    • Gastric bypass surgery
    • Malabsorption syndrome – Celiac and tropical sprue
    • Folate deficiency – For example, in patients undergoing chemotherapy with high-dose methotrexate
      • Thiamine serves as a coenzyme (in the form of thiamine pyrophosphate) in a variety of metabolic processes. In these processes, thiamine pyrophosphate is regenerated via the donation of a proton from the reduced form of nicotinamide adenine dinucleotide (NADH).
      • Folic acid is essential to having enough dihydrofolate reductase to regenerate NADH from its oxidative form. This regeneration allows NADH to continue to be present to regenerate thiamine pyrophosphate without being consumed in the process.
      • If folic acid is deficient in cells, it causes an indirect thiamine deficiency, because thiamine is present but cannot be activated.

Laboratory Studies

Diagnosis is usually based on a favorable response to treatment with thiamin in a patient with symptoms or signs of deficiency. Similar bilateral lower extremity polyneuropathies due to other disorders (eg, diabetes, alcoholism, vitamin B12 deficiency, heavy metal poisoning) do not respond to thiamin. Single-nerve neuritides (mononeuropathy—eg, sciatica) and multiple mononeuropathy (mononeuritis multiplex) are unlikely to result from thiamin deficiency.

Electrolytes, including Mg, should be measured to exclude other causes. For confirmation in equivocal cases, erythrocyte transketolase activity and 24-h urinary thiamine excretion may be measured.

Diagnosis of cardiovascular beriberi can be difficult if other disorders that cause heart failure are present. A therapeutic trial of thiamin can help.

Treatment

  • Supplemental thiamine, with dose based on clinical manifestations

For mild polyneuropathy, thiamine 10 to 20 mg once/day is given for 2 wk. For moderate or advanced neuropathy, the dose is 20 to 30 mg/day; it should be continued for several weeks after symptoms disappear. For edema and congestion due to cardiovascular beriberi, thiamine 100 mg IV once/day is given for several days. Heart failure is also treated.

For Wernicke-Korsakoff syndrome, thiamine 50 to 100 mg IM or IV bid must usually be given for several days, followed by 10 to 20 mg once/day until a therapeutic response is obtained. Anaphylactic reactions to IV thiamine are rare. Symptoms of ophthalmoplegia may resolve in a day; improvement in patients with Korsakoff psychosis may take 1 to 3 mo. Recovery from neurologic deficits is often incomplete in Wernicke-Korsakoff syndrome and in other forms of thiamine deficiency.

Because thiamine deficiency often occurs with other B vitamin deficiencies, multiple water-soluble vitamins are usually given for several weeks. Patients should continue to consume a nutritious diet, supplying 1 to 2 times the daily recommended intake (DRI) of vitamins; all alcohol intake should stop.

Prognosis

The prognosis for beriberi is usually good, unless patients have established Korsakoff syndrome. When patients have progressed to this stage, the degree of damage is only minimally reversible.

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Case Details

A 45 –year-old male, a known alcoholic from the previous 10 years reported to the physician for consultation. He complained of burning of eyes and a sore tongue. There was history of reduced appetite and mild abdominal discomfort.

The examination revealed cracks on the lips and in the corners of the mouth. The tongue was red, fissured and inflamed. The hair was dull , skin was oily  and nails were split.

What is the probable cause for all these manifestations?

What type of investigations should be carried out to know the cause of the disease?

Case discussion

The patient is most probably suffering from Vitamin B2 Deficiency (Riboflavin deficiency).

Vitamin B2 deficiency is frequent in chronic alcoholics.  It can also occur in patients with chronic liver diseases, and in hospitalized patients who receive total parenteral nutrition (TPN) with inadequate riboflavin supplementation. Riboflavin is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin supports energy production by aiding in the metabolism of fats, carbohydrates, and proteins. Characteristic symptoms of riboflavin deficiency include lesions of the skin, especially in the corners of the mouth, and a red, sore tongue. Assessment of Riboflavin Status can be done by Erythrocyte glutathione reductase activity.

Basic concept- The term “flavin” originates from the Latin word “flavus” referring to the yellow colour of vitamin B2- Riboflavin. This fluorescent riboflavin is a part of the vitamin B-complex. In the body, riboflavin occurs primarily as an integral component of the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).These coenzymes participate in a large majority of the reactions in the body.

Figure –1- showing structure of riboflavin. It contains D- ribitol, Isoalloxazine ring( Flavin Nucleus), 1 carbon is attached to 9 position of Iso- alloxazine nucleus.

Functions- Flavin coenzymes perform the following functions in the body-

A) Role in redox reactions- Flavin coenzymes are essential for energy production via the respiratory chain, as they act as catalysts in the transfer of electrons in numerous essential oxidation-reduction reactions (redox reactions).

B) Metabolic reactions-They participate in many metabolic reactions of carbohydrates, fats and proteins.  Some of the important reactions are as follows-

1) Oxidative decarboxylation of pyruvate and α-ketoglutarate.

2) Succinic dehydrogenase removes electrons from Succinate to form fumarate

3) Fatty acyl CoA dehydrogenase require FAD in fatty acid oxidation

4) As a coenzyme for Xanthine oxidase, FAD transfers electrons directly to oxygen

a) The enzyme contains FAD, Fe, and Mo

b) It converts Hypo Xanthine to Xanthine and then  to uric acid

5) Aldehyde oxidase uses FAD to oxidize aldehyde

a) Pyridoxal (vitamin B6)  is converted to pyridoxic acid (excreted)

b) Retinal (vitamin A) is converted to  retinoic acid

6) Pyridoxine phosphate oxidase which converts Pyridoxamine phosphate and pyridoxine phosphate to Pyridoxal phosphate (primary coenzyme form of vitamin B6 is dependent on FMN

7) Enzymes for choline catabolism require FAD

a) Choline dehydrogenase

b) Dimethyl glycine dehydrogenase

8) Metabolism of some amines requires FAD-dependent monoamine oxidase

a) Dopamine

b) Tyramine

c) Histamine

9) Reduction of GSSG to GSH is dependent on FAD-dependent glutathione reductase

10) FAD is required by Glycine oxidase enzyme.

11) FAD is a cofactor for methyltetrahydrofolate reductase and therefore modulates homocysteine metabolism. Synthesis of an active form of folate, N5 methyl Tetrahydrofolate, requires FADH2

12) Mitochondrial Glycerol-3- p dehydrogenase requires FAD

13) Oxidative Deamination of amino acids require flavoproteins

14) The vitamin also plays a role in drug and steroid metabolism, including detoxification reactions.

C) Biosynthetic role- Vitamin B2 also promotes normal growth and assists in the synthesis of steroids, red blood cells, and glycogen. Furthermore, it helps to maintain the integrity of mucous membranes, skin, eyes and the nervous system, and is involved in the production of adrenaline by the adrenal glands.

D) Antioxidant role-Riboflavin is also important for the antioxidant status within cell systems, both by itself and as part of the glutathione reductase and Xanthine oxidase system. This defense system may also help defend against bacterial infections and tumor cells.

Riboflavin deficiency

Water-soluble riboflavin is not stored in ample amounts; minute reserves are stored in the liver, kidneys, and heart. A constant supply is needed. Deficiency in this vitamin is usually part of a multiple-nutrient deficiency and does not occur in isolation.

Nutritional deficiency

Milk and other dairy products make the greatest contributions of riboflavin in western diets. Other common dietary sources include cereals, meats, and dark green vegetables (spinach, asparagus, and broccoli). Deficiency can occur with a diet deficient in these riboflavin-rich foods. Deficiency is uncommon in the United States with fortification of many food including grains and cereals. Daily consumption of breakfast cereal and milk would be expected to maintain an adequate intake of riboflavin. Riboflavin is extremely sensitive to light, and milk should be stored in containers that protect against photo degradation.

Additional risk factors

The condition is more commonly seen in persons with such risk factors as pregnancy,lactation, phototherapy for hyperbilirubinemia (in premature infants), advanced age,low-income, and/or depression. Riboflavin is absorbed in the proximal small intestine. Malabsorption from such conditions as celiac sprue, malignancies, and alcoholism can also promote deficiency of riboflavin. Riboflavin is transported in the bloodstream as a flavin-protein complex, which means that nonavailability of the carrier protein also leads to apparent riboflavin deficiency. Similarly, it is possible for antagonists to interfere with absorption and/or transport and thus create an apparent deficiency at receptor sites.

Riboflavin deficiency may also occur as a result of:

  • trauma, including burns and surgery
  • chronic disorders (e.g. rheumatic fever, tuberculosis, sub acute bacterial endocarditis, diabetes, hypothyroidism, liver cirrhosis)
  • chronic medication (tranquillizers, oral-contraceptives, thyroid hormones, fiber-based laxatives, antibiotics)
  • high physical activity

Diagnosis

Riboflavin deficiency is usually associated with other vitamin B complex deficiencies, and isolated deficiency is rare.However, it has been associated with multiple clinical manifestations.

Riboflavin deficiency most commonly associated with dermatologic conditions, such as the following:

1) Cheilosis, or chapping and fissuring of the lips.

Figure –2- showing cheilosis.

2) A sore, red tongue (Glossitis)

Figure –3- showing glossitis

3) Oily, scaly skin rashes on the scrotum, vulva and philtrum

4) Deficiency can be associated with some developmental abnormalities, such as the following:

a) Cleft lip and palate deformities

b)  Growth retardation in infants and children

c) Congenital heart defects

5) Other associations of deficiency include the following:

  • Red, itchy eyes
  • Night blindness
  • Cataracts
  • Migraines
  • Peripheral neuropathy
  • Mild anemia (secondary to interference with iron absorption)
  • Fatigue
  • Malignancy (esophageal and cervical dysplasia)

Laboratory Investigations

  • Measurement of RBC glutathione reductase activity may help in the detection of riboflavin deficiency. An increase in the stimulation of this enzymatic reaction confirms a low-level of riboflavin.
  • Measurement of red blood cell or urinary riboflavin concentrations can also help in diagnosis.
  • Direct methods include the determination of FAD and FMN in whole blood by HPLC (High Performance Liquid Chromatography).

Treatment

  • Treatment for riboflavin deficiency consists of riboflavin replenishment, with care taken not to overlook coexisting B-complex deficiencies.
  • The recommended nutrient intake (RNI) of riboflavin is 0.6 mg/5000 kJ daily.
  • The daily RNI ranges are 0.3-0.6 mg for infants, 0.7-1.1 mg for children, 1.1-1.4 mg for adolescents, and 1-1.6 mg for adults.
  • Recommended increased requirements for pregnant and lactating women are as follows:
    • Additional 0.1 mg/d in the first trimester
    • Additional 0.3 mg/d in the second and third trimesters
    • Additional 0.4 mg/d during lactation
    • Oral riboflavin doses of 1-4 mg daily are usually considered sufficient as a nutritional supplement in patients with normal GI absorption. These doses should be present in the normal diet. Doses for deficiency treatment are slightly higher.
    • Because the capacity of the gastrointestinal tract to absorb riboflavin is limited (~20 mg if given in one oral dose), riboflavin toxicity has not been described.
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Case Details

A  4 -year-old boy was brought for consultation for hematuria, edema of lower extremities as well as swollen right leg. He was the 12the born in a poor family, where one previous child died from malnutrition and dehydration in the period of infancy.  The child was fed only with cow’s milk and biscuits.

From the period of five months,the boy manifested irritability, sweating, poor appetite and cried when somebody touched him

At admission the baby was afebrile, pale, and malnourished; his hair was dry and cracked. Clinical evaluation showed no organomegaly, no neurological signs, gingival bleeding was there and only one tooth was present.

Laboratory findings were as follows

Red Blood Cell Count 3.5 million/mm3

Hemoglobin (Hb) 7 g/dl

Haemtocrit (Hct) 30%

Serum Iron low

Liver functional tests were in the normal range.

Ultrasound of kidney was normal.

Doppler of blood vessels of both legs was normal which excluded thrombophlebitis. Swelling of the right leg indicated radiological investigation. Massive subperiosteal hematoma on the right femur, dilatated metaphyses and general osteoporosis had been present on the radiogram.

What is the probable diagnosis for this child ?

Case details- The child is most probably suffering from Scurvy (Vitamin C deficiency). As the history suggests the child had been an ignored child, fed a diet deficient in fruits and vegetables and the signs and symptoms are also typical of scurvy. Bleeding gums, tooth loss, Sub periosteal hematoma and bony changes are characteristic of scurvy. Iron deficiency anemia  is  also  there which is very common in scurvy due to various reasons.

Thus considering the osteoskeletal manifestations, malnutrition, anemia, irritability and bleeding tendencies as well as the radiological findings, deficiency of vitamin C is concluded.

Scurvy

Scurvy is a state of dietary deficiency of vitamin C (ascorbic acid). The human body lacks the ability to synthesize vitaminC and therefore depends on exogenous dietary sources to meet vitamin C needs. The enzyme, L-gluconolactone oxidase, which would usually catalyze the conversionof L-gluconolactone to L-ascorbic acid, is defective due to a mutation.

Vitamin C – An overview

Vitamin C (ascorbic acid) plays a role in collagen, carnitine,hormone, and amino acid formation. It is essential for wound healing and facilitates recovery from burns. Vitamin C is also an antioxidant, supports immune function, and facilitates the absorption of iron.

Causes of Vitamin C (Ascorbic Acid) Deficiency

Scurvy is caused by a dietary deficiency of vitamin C. The body’s pool of vitamin C can be depleted in 1-3 months.

  • Risk factors include the following:
    • Babies who are fed only cow’s milk during the first year of life are at risk.
    • Alcoholism  and conforming to food fads are risk factors.
    • Elderly individuals who eat a tea-and-toast diet are at risk. Retired people who live alone and those who eat primarily fast food face increased risk of deficiency.
    • Economically disadvantaged persons tend to not purchase foods high in vitamin C (eg, green vegetables, citrus fruits), which results in them being at high risk.
    • More recently, vitamin C deficiency has been noted in refugees who are dependent on external suppliers for their food and have limited access to fresh fruits and vegetables.
    • Cigarette smokers require increased intake of vitamin C because of lower vitamin C absorption and increased catabolism.
    • Pregnant and lactating women and those with thyrotoxicosis require increased intake of vitamin C because of increased utilization.
    • People with anorexia nervosa or anorexia from other diseases such as AIDS or cancer are at increased risk of vitamin C deficiency.
    • People with type 1 diabetes have increased vitamin C requirements, as do those on hemodialysis and peritoneal dialysis.
    • Because vitamin C is absorbed in the small intestine, people with disease of the small intestine such as Crohn, Whipple, and celiac disease are at risk.
    • Iron overload disorders may lead to renal vitamin C wasting.

Pathophysiology

Vitamin C is functionally most relevant for the triple-helix formation of collagen; a vitamin C deficiency results in impaired collagen synthesis. Proline and lysine hydroxylases are required for the post synthetic modification of procollagen to collagen. Vitamin C is necessary as a coenzyme for these hydroxylases. 

Formation of intercellular cement substances in connective tissues, bones, and dentin is defective, resulting in weakened capillaries with subsequent hemorrhage and defects in bone and related structures. Hemorrhaging is a hallmark feature of scurvy and can occur in any organ. Hair follicles are one of the common sites of cutaneous bleeding. 

Bone tissue formation becomes impaired, which, in children, causes bone lesions and poor bone growth. Fibrous tissue forms between the diaphysis and the epiphysis,and costochondral junctions enlarge. Densely calcified fragments of cartilage are embedded in the fibrous tissue. Subperiosteal hemorrhages, sometimes due to small fractures, may occur in children or adults.

Clinical Manifestations

  • Early symptoms are malaise and lethargy.
  • After 1-3 months, patients develop shortness of breath and bone pain.
  • Myalgias may occur because of reduced carnitine production.
  • Other symptoms include skin changes with roughness, easy bruising and petechiae, gum disease(figure-1) , loosening of teeth, poor wound healing, and emotional changes.

Figure-1- showing bleeding gums

  • Dry mouth and dry eyes similar to Sjögren syndrome may occur.
  • In the late stages, jaundice, generalized edema, oliguria, neuropathy, fever, and convulsions can be seen.
  • Vital signs: Hypotension may be observed late in the disease. This may be due to an inability of the resistance vessels to constrict in response to adrenergic stimuli.
  • Skin: Perifollicular hemorrhages (figure-2),purpura, and ecchymoses are seen most commonly on the legs and buttocks where hydrostatic pressure is the greatest. Poor wound healing and breakdown of old scars may be seen.
  • Nails: Splinter hemorrhages may occur.

Figure- 2- showing hemorrhages in the nail bed

  • Head and neck: Gum swelling, friability, bleeding, and infection with loose teeth; mucosal petechiae; scleral icterus (late, probably secondary to hemolysis); and pale conjunctiva are seen. Conjunctival hemorrhage, flame-shaped hemorrhages, and cotton-wool spots may be seen. Bleeding into the periorbital area, eyelids, and retrobulbar space also can be seen. Alopecia may occur secondary to reduced disulfide bonding.
  • Chest and cardiovascular: Scorbutic rosary (ie, sternum sinks inward) may occur in children. High-output heart failure due to anemia can be observed. Bleeding into the myocardium and pericardial space has been reported.

Figure-3- showing scorbutic rosary

  • Extremities: Fractures, dislocations, and tenderness of bones are common in children. Bleeding into muscles and joints may be seen. Edema may occur late in the disease.
  • Gastrointestinal: Loss of weight secondary to anorexia is common. 

Figure-4- showing  perifollicular hemorrhages

Diagnosis

Diagnosis is usually made clinically in a patient who has skin or gingival signs and is at risk of vitamin C deficiency 

Laboratory Investigations

A plasma or leukocyte vitamin C level can confirm clinical diagnosis.

  • Scurvy occurs at levels generally less than 0.1 mg/dL.
  • Symptoms occur at levels below 2.5 mg/L, which is considered deficiency.
  • Levels of 2.5-5 mg/L indicate depletion.
  • Levels can be low in patients who have tuberculosis, rheumatic fever, or other chronic illnesses; those who smoke cigarettes; and patients on oral contraceptive drugs.
  • Capillary fragility can be checked by inflating a blood pressure cuff and looking for petechiae on the forearm.
  • Bleeding time, clotting time and Prothrombin time are normal.
  • An Fe deficiency anemia is generally observed.
  • Imaging Studies

    Skeletal x-rays can help diagnose childhood (but not adult) scurvy. Changes are most evident at the ends of long bones, particularly at the knee.

    ·        Early changes resemble atrophy.

    ·        Loss of trabeculae results in a ground-glass appearance.

    ·        The cortex thins.

    ·        A line of calcified, irregular cartilage(white line of Fraenkel) may be visible at the metaphysis.

    ·        The epiphysis may be compressed.

    ·        Healing subperiosteal hemorrhages may elevate and calcify the periosteum.

    Differential Diagnosis

    In adults, scurvy must be differentiated from arthritis, hemorrhagic disorders, gingivitis, and protein-energy malnutrition.

    Treatment

    Patients should take ascorbic acid at 100mg 3-5 times a day until total of 4 g is reached, and then they should decrease intake to 100 mg daily.
    Alternately, ascorbic acid may be taken at 1 g/d for the first 3-5 days followed by 300-500 mg/d for a week. Then the recommended daily allowance is resumed.

    • Divided doses are given because intestinal absorption is limited to 100 mg at one time.
    • Parenteral doses are necessary in those with gastro intestinal malabsorption.

    Diet

    Foods high in vitamin C include the following.

    • Citrus fruits, especially grapefruits and lemons
    • Vegetables, including broccoli, green peppers, tomatoes, potatoes, and cabbage
  • The recommended daily allowance for vitamin C varies. The current recommendation for adults is 120 mg daily, although a dose of 60 mg daily is all that is required to prevent scurvy.
  • Diets high in vitamin C have been claimed to lower the incidence of certain cancers, particularly esophageal and gastric cancers.    
  • Toxicity

    Taking>2 g of vitamin C in a single dose may result in abdominal pain, diarrhea,and nausea. Since vitamin C may be metabolized to oxalate, it is feared that chronic, high-dose vitamin C supplementation could result in an increased prevalence of kidney stones.. Thus, it is reasonable to advise patients with a past history of kidney stones to not take large doses of vitamin C. There is also an unproven but possible risk that chronic high doses of vitamin C could promote iron overload in patients taking supplemental iron.

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    Case Details

    A 32- year- old male reported to emergency with active bleeding from nose.  History revealed that he had been on Orlistat for weight reduction from the past two years. He had started Orlistat without the advice of any practitioner and  had lost nearly 20 kg of body weight .There was no history of hypertension, bleeding disorder or any other medical illness.No such bleeding episode occurred in the past.

    There was no abnormality detected upon local examination of nose.  What is the relationship between Orlistat and epistaxis?

    Case Discussion

    The patient has most probably developed vitamin K deficiency. Absorption of vitamin K might have been decreased by Orlistat (weight loss medication).

    Orlistat is available as brand name Xenical. The FDA approved Orlistat by prescription in 1999,  however, alli, a lower dose formulation of Orlistat, was approved for purchase without a prescription “over the counter” in 2007.  

    Orlistat works by inhibiting gastric and pancreatic lipases, the enzymes that break down triglycerides in the intestine. When lipase activity is blocked, triglycerides from diet are not hydrolyzed into absorbable free fatty acids, and are excreted undigested instead. The side effects of the drug are mainly gastrointestinal and include steatorrhea (oily, loose stools with excessive flatus due to unabsorbed fats reaching the large intestine), fecal incontinence and frequent or urgent bowel movements.

    Fat malabsorption is associated with impaired absorption of vitamin K and other fat soluble vitamins. Vitamin K is important for the coagulation process.

    It acts as a cofactor for an enzyme that catalyzes the carboxylation of the amino acid, glutamic acid, resulting in its conversion to gamma-carboxy glutamic acid (Gla). Although vitamin K-dependent gamma-carboxylation occurs only on specific glutamic acid residues in a small number of vitamin K-dependent proteins, it is critical to the calcium-binding function of those proteins. The ability to bind calcium ions (Ca2+)is required for the activation of the seven vitamin K-dependent clotting factors, or proteins, in the coagulation cascade. In its deficiency coagulation process is grossly affected resulting in tendency for bleeding and hemorrhages.Absorption of vitamin K may also be decreased by mineral oil and bile acid sequestrants (Cholestyramine, colestipol), used for lowering serum cholesterol level in cases of hypercholesterolemia..

    Vitamin K deficiency is uncommon in healthy adults but occurs in individuals with gastrointestinal disorders, fat malabsorption or liver disease, or after prolonged antibiotic therapy coupled with compromised dietary intake. Impaired blood clotting is the clinical symptom of vitamin K deficiency, which is demonstrated by measuring clotting time. In severe cases, bleeding occurs. Vitamin K-dependent coagulation factors are synthesized in liver. Consequently, severe liver disease results in lower blood levels of vitamin K-dependent clotting factors and an increased risk of uncontrolled bleeding (hemorrhage). 

    In the given case, there is no other possibility of bleeding from any other cause, it could only be due to Orlistat induced vitamin K deficiency.  Thus Orlistat should always be supplemented with vitamins. Besides that the patients on warfarin or Dicumarol(Vitamin K antagonists) should be regularly monitored if they are simultaneously taking Orlistat.

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