Acquired methemoglobinemia. The relationship of cause to course of illness
J. R. Avner, F. M. Henretig and C. M. McAneney
Division of General Pediatrics, Children's Hospital, Philadelphia.
To better characterize methemoglobinemia in children, we reviewed the
charts of 17 patients who were admitted to a children's hospital over the
last 10 years. Two distinct groups were identified: (1) The endogenous
group (n = 9) included patients with methemoglobinemia associated with an
intercurrent illness. (2) The exogenous group (n = 8) included patients
with methemoglobinemia secondary to drug exposure. Despite similar initial
methemoglobin levels in the endogenous (mean, 29%) and exogenous (mean,
28%) groups, children in the endogenous group had more acidosis (serum
bicarbonate levels of 5.9 vs 19.1 mmol/L and arterial pH of 7.01 vs 7.35).
All the children in the exogenous group with methemoglobinemia secondary to
an accidental ingestion stayed only 1 day in the hospital, while children
in the endogenous group were admitted for an average of 19 days. Children
with methemoglobinemia secondary to a drug exposure have a more benign
illness with a shorter duration than children with methemoglobinemia
associated with an intercurrent illness. It appears that the absolute level
of methemoglobin is not as important as the underlying cause in determining
both the course and severity of illness.
