Hypochloremic, Hypokalemic Metabolic Alkalosis in an Infant Given Chloride-Deficient Formula

 

History: use of a milk formula with insufficient chloride for several months

 

Clinical findings:

(1) loss of appetite

(2) failure to thrive

(3) muscle weakness

(4) lethargy

 

Laboratory findings:

(1) low serum chloride concentration

(2) serum sodium concentration usually normal

(3) metabolic alkalosis (elevated bicarbonate, normal to slightly increased PaCO2)

(4) severe hypokalemia

 

Differential diagnosis - exclude other causes of metabolic alkalosis:

(1) chronic vomiting or diarrhea

(2) potassium wastage

 

Management:

(1) Repletion of potassium and chloride deficiencies.

(2) Change in formula to one with adequate chloride.