A 32-year-old male presents after slipping and falling off the roof of his home and striking his head. He suffered a brief loss of consciousness. Since that time, he has noted increasing urination and thirst. His serum chemistries reveal an elevated sodium level. His urine specific gravity is 1.003. Which of the following is the most likely diagnosis?
- cerebral contusion
- subarachnoid hemorrhage
- epidural hematoma
- diabetes insipidus
- renal contusion
Answer: D
Diabetes insipidus
Diabetes insipidus (ADH deficiency) can occur after acute head trauma. ADH is secreted by the posterior pituitary gland and causes the body to retain fluid (to increase volume). In a patient who has damaged the posterior pituitary, ADH is not secreted, so the body urinates "water." There is frequent large volume urination with a very low specific gravity and will cause hypernatremia unless the patient is given large quantities of water to drink.
Know Your Content Blueprint
Diabetes insipidus is covered in the NCCPA™ Content Blueprint Endocrinology (6%)
6-year-old with polyuria, weight loss, and recent seizures (watch video)
Learn more about diabetes insipidus, watch the ReelDX patient video case and take the lesson quiz at SMARTY PANCE Diabetes Insipidus