Hyper-Reactive Malarial Splenomegaly Syndrome – A Case Series Posing a Diagnostic Enigma

Hyper-reactive malarial splenomegaly syndrome (HMSS) is an underrecognized complication of malarial infection in endemic regions. Diagnosis of this condition is often elusive. In this case series, patients with spleen size ≥10 cm were enrolled, and a diagnostic algorithm (in addition to Fakunle criteria) was used to exclude close differentials. After ruling out other causes, all were given chloroquine therapy. HMSS was confirmed when ≥40% splenic regression was found at 6-month follow-up. We observed 11 patients (10 female, 1 male; mean age 15.7 years; mean spleen size 12.65 cm) during the study period of 1 year. After excluding other etiologies, serum IgM levels were sent in all and found to be elevated in 7/11 patients. All received chloroquine for acute and long-term management. Five of seven patients who have completed six-month follow-up demonstrated ≥40% spleen regression, confirming the diagnosis. Diagnosis of HMSS remains that of exclusion. High IgM levels offer supportive evidence; normal baseline values do not exclude the diagnosis. A trial of chloroquine may help make a retrospective confirmatory diagnosis. Compliance with therapy, follow-up, and mosquito control measures are the cornerstones of management.