A)
Etiology: Complication of posterior pituary insufficiency
or Central DI (CVA, CNS trauma, CNS Surgery, Sellar-Suprasellar
tumors, TB, Sarcoidosis, Histiocytosis, Meningitis, Idiopathic);
Nephrogenic DI (Sickle Cell Trait or Disease, Medullary Cystic Disease,
Obstructive Renal Disease, inc Ca++, dec K+, Lithium, Genetic Inheritance).
B) Diagnosis: Polyuria: 4-8 l/day; Urine
Osm 200-400 mOsm/l; Serum Osm > 300 mOsm/l; Na+ >145.
C) Management: DDAVP (2 ug SubQ q 12-24
hrs); Patients with DI secondary to CNS trauma or neurosurgery should
receive stress doses of hydrocortisone for presumed anterior pituitary
damage. Suspect basilar skull fracture and CSF leak in patients
who have DI secondary to CNS trauma.
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