Question

A patient excreted 3250ml of urine on each of 2 consecutive days at home. The patient was hospitalized and deprived of water. The urine osmolatity prior to water deprivation was 210mOsm/ks. The urine osmolality subsequent to water deptivation was 240 mOsm/kg. An injection of ADH was given. One hour later the urine osmolafity was 300 mOsm/kg. What is the most likely diagnosis? Explain:

Answer 1

The most likely diagnosis for the patient in this case is diabetes insipidus, which is characterized by reduced water absorption in the kidneys. The patient had high urine osmolality prior to water deprivation, indicating normal kidney function. However, after water deprivation and injection of ADH, the urine osmolality increased significantly, suggesting an inability to reabsorb water effectively.

Step-by-step explanation:

The most likely diagnosis for the patient in this case is diabetes insipidus.

Diabetes insipidus is a condition characterized by insufficient pituitary antidiuretic hormone (ADH) release or insufficient numbers of ADH receptors in the collecting ducts, resulting in reduced water absorption in the kidneys.

In this case, the patient had high urine osmolality prior to water deprivation, indicating that their kidneys were able to concentrate urine properly. However, after the water deprivation and injection of ADH, the urine osmolality increased significantly, suggesting that the kidneys were unable to reabsorb water effectively, which is a characteristic feature of diabetes insipidus.