A case of congenital chloride diarrhea: information obtained through long-term follow-up with reduced electrolyte substitution

Congenital chloride diarrhea (CCD) is an inherited disorder of intestinal electrolyte transport that results in a large wastage of electrolytes and water. The patient, who is now 24 years old, was diagnosed at the age of 16 months with CCD based on hypochloremic alkalosis, hyponatremia, and hypokalemia with increased plasma renin and aldosterone levels, and high fecal Cl⁻. Serum Na⁺ and plasma aldosterone levels were normalized by replacement therapy with NaCl [8 mmol/(kg day)] and KCl [3 mmol/(kg day)]. On follow-up, watery diarrhea persisted, and she was frequently noted to have hypokalemia despite normal serum Na⁺ and Cl⁻ and plasma aldosterone levels with only reduced dosages of KCl [1–1.5 mmol/(kg day)] substitution due to only sporadic ambulatory care and unsatisfactory compliance with medication, and a normal diet. However, she had acceptable growth, normal renal function, and had an uneventful pregnancy and delivery of a healthy child. In adolescence and adulthood, hypokalemia may be the main problem requiring treatment, and substitution therapy with adequate doses of KCl alone may be sufficient, although a combination of NaCl and KCl is generally recommended even after childhood.