Case 1: Acute starvation:
A 23-year-old woman living alone depressed after the termination of her engagement. Two months later she was brought to the emergency room by a friend
because of weakness and lethargy. She appeared thin and pale. Questioning revealed that she had not eaten for several weeks. Analysis of plasma sample
indicated elevated levels of alanine, acetoacetate, beta-hydroxybutyrate, and blood urea nitrogen (BUN).
However, her plasma glucose level was within the normal range. She was hospitalized, given intravenous feeding and antidepressant medication, and
subsequently switched to an 1800 cal (7500 KJ) diet. Her recovery was uneventful.
Discuss this case applying your knowledge on carbohydrate, lipid and amino acid metabolism to answer the following questions.
1. How was the patient’s body obtaining energy during the time she was not eating?
2. How was the patient able to maintain her plasma glucose level within the normal range even though she was not eating?
3. What does elevation in plasma alanine indicate? Why is the BUN elevated?
5. Why her plasma acetoacteate and beta-hydroxybutyrate levels high?
6. Would you expect to see similar conditions in a patient with uncontrolled diabetic condition? Why?
Case 2: Phenylketonuria
A 2-wk old female responded positively to a test for PKU administered on discharge from the hospital following her birth. She was called back for further
testing. Serum Phe concentration was 30 mg/dl (normal: 1 mg/dl) and tyrosine was 2 mg/dl. The urine was positive for phenolic acids and FeCl3 detected
ketones. A diagnosis of classic PKU was made and the child was maintained on a diet low in Phe.
1. What enzymatic reactions are defective in the patient with PKU?
2. What are the physiologic consequences of PKU?
3. Why PKU should be detected as early as possible?
4. What is the incidence of PKU among various ethnic groups?
5. What is the treatment for the patient with PKU?
Case 3: Heriditary Hyperammonemia
A 6-month-old infant began to vomit occasionally and ceased to gain weight. At age 81/2 months he was readmitted to the hospital. Routine examination
and laboratory tests were normal, but after 1 wk. he became habitually drowsy, his liver was enlarged. The electroencephalogram was grossly abnormal.
Since the infant could not retain milk given by gavage feeding, IV glucose was administered. He improved rapidly. Urine analysis showed abnormally high
amounts of glutamine and uracil. This suggested a high blood ammonium concentration which was confirmed by the laboratory.
1. Which urea cycle enzyme (s) may be defective in this patient considering the lab data?
2. Why was the urine glutamine concentration elevated?
3. Why this disease is lethal in male patients but not in females?
4. Why the liver in this patient was enlarged?
5. How would you treat a similar patient today?