Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:54

794 Hyponatremia Hypophosphatemia

➣Cerebral edema caused by acute severe fall in serum Na

➣Patient may develop seizures or go into coma.

➣Usually seen in postoperative patients

➣Premenopausal women are particularly susceptible.

➣Rapid treatment of hyponatremia is needed.

■Due to therapy

➣Osmotic demyelination (also known as central pontine myeli-

nolysis)

➣Seen with excessive correction of Na (>12 mEq /24 hrs) in chronic

hyponatremia

➣Alcoholics, burn victims and severely hypokalemic patients are

very susceptible to this syndrome.

➣Prevented by gentle correction of serum Na (up to 12 mEq/L/day)

in chronic hyponatremia

Hypophosphatemia..................................

SHARON M. MOE, MD

history & physical

History

■Observed in 10% of hospitalized alcoholics

■Gastrointestinal disorders, diarrhea, recent severe illness, weight

change

■Diabetic ketoacidosis

■Critical illness/ventilated – observed in 3% of all hospitalized

patients, up to 70% of ICU patients on TPN

■New medications, renal transplant

Signs & Symptoms

■Usually only present if phosphorus <1 mg/dl, or occasionally <2.5

mg/dl if chronic loss

■Skeletal muscle: weakness, respiratory failure, rhabdomyolysis

■CNS: seizures, delirium, coma, paresthesias, encephalopathy

■Cardiac: cardiomyopathy, CHF

■Hematopoeitic: RBC hemolysis, thrombocytopenia, hemorrhage,

WBC dysfunction

■Bone: osteomalacia/rickets

■Renal: decreased GFR, tubular abnormalities, insulin resistance