Differential Diagnosis
- Single most likely diagnosis
- Diabetes Insipidus (B): The patient's symptoms of increased thirst and frequent urination, along with the laboratory findings of low urine specific gravity (1.002) and hypernatremia (140 mEq/L), are consistent with diabetes insipidus. The low specific gravity indicates that the urine is not being concentrated properly, which is a hallmark of this condition.
- Other Likely diagnoses
- Type 1 Diabetes Mellitus (D): Although the glucose level is not provided, the presence of glucose in the urine (1+) could suggest type 1 diabetes mellitus. However, the absence of ketones in the urine makes this diagnosis less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Adrenal Insufficiency (A): Although less likely, adrenal insufficiency can present with dehydration and electrolyte imbalances. It is a life-threatening condition if not recognized and treated promptly.
- Syndrome of Inappropriate ADH Secretion (C): This condition can cause hyponatremia, which is not present in this case. However, it is a potential diagnosis to consider in patients with urinary concentration abnormalities.
- Rare diagnoses
- Urinary Tract Infection (E): While a urinary tract infection could cause frequent urination, it would not typically cause the degree of dehydration and electrolyte imbalance seen in this patient.
- Other rare causes of diabetes insipidus, such as nephrogenic diabetes insipidus or central diabetes insipidus due to a pituitary tumor, could also be considered but are less likely given the patient's presentation and laboratory findings.