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Case study-1

A 2 -week –old child was brought to the emergency. The parents were fearful that the child had been given some poison as they noted black discoloration on the diaper. They had delayed disposing one of the child’s diapers and noted black discoloration where the urine had collected. Later, they realized that all of the child’s diapers would turn black if kept unwashed for a longer time.

The attending pediatrician examined the child and explained them that it was due to an amino acid disorder.

Which amino acid pathway is implicated in this phenomenon?

What is the cause of blackening of the diapers?

How can this defect be treated?


Case Study-2

A 12-year-old boy was admitted to the hospital with a red scaly rash and mild cerebellar ataxia. His mother thought that the boy is suffering from Pellagra because the same symptoms in her older daughter had been so diagnosed earlier. The boy did not have the usual dietary deficiency form of Pellagra, but large amounts of free amino acids were found in his urine. When the older daughter had a recurrent attack of ataxia, it was found that her urine also contained excessive amount of amino acids. Two other siblings had the sane aminoaciduria; however four others were normal. The parents were asymptomatic, but a family history revealed that they were first cousins.

Assuming that this defect is inherited, what abnormality could account for the unusual amount of amino acids in urine and what is its relationship with pellagra like rashes?

How can this defect be treated?


Case study-3

A 2-week –old infant with refusal to feed lethargy, excessive cry and irritability, responded positively to a test for Phenylketonuria, A diagnosis of Classical  Phenylketonuria (PKU) was made and the child was maintained on a low Phenyl Alanine diet.Serum Phenyl Alanine was 30 mg/dl and Tyrosine was 2mg/dl. Ferric chloride test was positive for urine. A diagnosis of Classical Phenylketonuria (PKU) was made and the child was maintained on a low Phenyl Alanine diet.

What enzymatic reactions are defective in the patient with PKU?

What are the physiological consequences of PKU and why it should be detected as early as possible?

What is the treatment for this disease?


 Case study-4

A child presented with severe vomiting, dehydration and fever. History revealed that the child was born normal but was not growing well from the last few months. There was progressive mental retardation. Urine analysis revealed the presence of branched amino acids and their Keto acids in high amount. Preliminary results from the blood amino acid screen showed two elevated amino acids with non polar side chains.

Blood studies showed acidosis with a low bicarbonate concentration. The urine of the patient had a smell of burnt sugar. Urine analysis revealed the presence of branched amino acids and their Keto acids in high amount. Preliminary results from the blood amino acid screen showed two elevated amino acids with non polar side chains.

What is the probable defect?

What is the basis for these symptoms?


Case study-5

A 38- year- old female reported with a dull pain in the left flank. The pain was radiating towards left leg. She was in real agony. She reported that there was fever and inability to pass urine from the last few days. History revealed that she was admitted twice with the similar symptoms in the previous six months. .

On general physical examination, she was found to be anemic, pulse was 80/minute, B.P. was 130/90 mm Hg and the abdomen was tender to touch. The patient was admitted for observation and treatment. There was Costovertrebral angle tenderness on Murphy’s punch.

Routine urinalysis revealed the presence of RBCs, pus cells, WBC casts, characteristic hexagonal crystals and amino acids. A diagnosis of aminoaciduria was made.

What is the probable defect? Which amino acid is expected to be there in urine?

What is the possible treatment?


Case study-6

A 54-year-old post menopausal woman, presented to internist for care of hot flashes that have returned 2 years after menopause. The symptoms occurred mostly after meals, when she drank wine, or when she went for running. There was history of hypertension and frequent diarrhea also. The patient was referred to gynecologist. The general physical examination was entirely normal. Hormone-replacement therapy (HRT) was prescribed to the patient and she was referred to gastroenterologist (GI) for Irritable Bowel Syndrome (IBS) treatment.  She experienced 2 hot flashes with no sweating during the examination.

Patient returned 3 months later with no improvement in hot flashes. A different formulation of  HRT was prescribed. Patient returned to GI doctor 1 year later with worsening of her IBS. Patient reported cramping, abdominal pain, and increased episodes of diarrhea. She had to wake up at night with diarrhea. Patient discontinued her HRT   although they were ineffective. After 1 year, patient was in need of emergency care. She presented with acute bowel obstruction and was taken to the operating room.

There was marked fibrosis of the terminal ileum with multiple hairpin turns of the bowel and a small tumor in the terminal ileum. Pathological report concluded that the patient had Carcinoid syndrome.

What is the probable defect in Carcinoid syndrome?

How can this be diagnosed at the earliest possible? What is the biochemical basis for all the clinical manifestations?

What is the prognosis of this disease?






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