Charles, a 4-month-old Asian boy, is brought to his pediatrician by his mother.
ID: 263359 • Letter: C
Question
Charles, a 4-month-old Asian boy, is brought to his pediatrician by his mother. Charles has two older sisters, and his mother has noticed that he is nursing much more frequently than they did. She thinks this heavy nursing is the cause of the excessive amounts of urine he is producing. She reports that he wants to nurse every hour, and she has to change his diaper about every 30 minutes. In addition, because of the frequency of nursing, she is using an infant formula to supplement her milk in order to meet Charles’s demands.
When reviewing the records of Charles’s two sisters, the pediatrician notes that none of these symptoms were reported for either sister. The pediatrician completes a physical examination and notes the following:
Vital signs:
Rectal temperature = 98.9°F (37.2°C)
Heart rate = 85 beats/min
Respiratory rate = 13 breaths/min
Has lost some weight since last visit.
Reflexes: All within normal range, but slightly excitable.
Skin and mucous membranes: Lack of skin turgor; sunken fontanels; mucous membranes dry.
Based on the results of the physical examination, the pediatrician asks to take both blood and urine samples for analysis. The mother agrees, and the results are as follows:
Blood:
Hematocrit (Hct) = 59%
Serum sodium = 139 mEq/L
Serum potassium = 5 mEq/L
Serum bicarbonate = 21 mEq/L
Serum chloride = 109 mEq/L
Urine:
Specific gravity = 1.001
pH = 6.8
Glucose, protein, lipids, blood all absent
Based on this case study answer the following questions.
DIAGNOSIS:
1. Why this problem is it not seen in either of his parents? If Charles later has a baby brother, would you expect the baby to have this disorder? Explain.
2. What aspects of the history, physical examination, and laboratory tests support the diagnosis?
3. If you were the pediatrician and Charles’s mother asked you if he was going to need injections and dietary restrictions, what would you tell her?
4. As Charles gets older, what type of counseling should he receive to help him control this disorder?
5. What will be the consequences if Charles disregards this counseling?
Explanation / Answer
Charles, a 4-month-old Asian boy, is brought to his pediatrician by his mother.