Neurological Disorders Q 80

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The client with a head injury has been urinating copious amounts of dilute urine through the Foley catheter. The client’s urine output for the previous shift was 3000 ml. The nurse implements a new physician order to administer:

  

     A. desmopressin (DDAVP, Stimate)

     B. Dexamethasone (Decadron)

     B. Dexamethasone (Decadron) C. ethacrynic acid (Edecrin)

     D. mannitol (Osmitrol)

    

    

Correct Answer: A. Desmopressin (DDAVP, stimate)

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A complication of a head injury is diabetes insipidus, which can occur with insult to the hypothalamus, the antidiuretic storage vesicles, or the posterior pituitary gland. Urine output that exceeds 9 L per day generally requires treatment with desmopressin. Desmopressin administration can be utilized to distinguish between central vs. nephrogenic diabetes insipidus, with a positive response noted in central diabetes insipidus, meaning the kidneys respond appropriately to desmopressin with the expected concentration of the urine and increased reabsorption of fluids, resulting in eutonic urine.

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Option B: Dexamethasone, a glucocorticoid, is administered to treat cerebral edema. This medication may be ordered for the head injured patient. Dexamethasone has a wide variety of uses in the medical field. As a treatment, dexamethasone has been useful in the treatment of acute exacerbations of multiple sclerosis, allergies, cerebral edema, inflammation, and shock.

Option C: Ethacrynic acid is a loop diuretic that gained FDA approval for widespread use in 1967. Unlike other loop diuretics, ethacrynic acid is a novel drug due to the absence of a sulfonamide group in its structure, allowing its use in critically ill patients with life-threatening sulfa-allergies. In adults, ethacrynic acid is a choice for the relief of edema in patients with renal failure, congestive heart failure, and cirrhotic ascites in the setting of sulfonamide hypersensitivity and treatment-resistant pathologies.

Option D: Mannitol is a diuretic, which would be contraindicated. Mannitol is a six-carbon, linear, simple sugar which is only mildly metabolized by the body and primarily excreted rapidly by the kidneys when given intravenously and poorly absorbed when taken orally.

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