Acute Intermittent Porphyria Triggered by <scp>COVID</scp> ‐19 Mimicking Guillain–Barré Syndrome: A Diagnostic Challenge

ABSTRACT Acute intermittent porphyria (AIP) is a rare heme biosynthesis disorder in which the accumulation of neurotoxic porphyrin precursors precipitates neurovisceral attacks. Intercurrent infections, including coronavirus disease 2019 (COVID‐19), may trigger or exacerbate AIP and complicate diagnosis, as clinical manifestations can resemble those of other acute neuropathies. This report describes a 16‐year‐old girl who developed abdominal pain, seizures, and rapidly progressive acute motor neuropathy shortly after COVID‐19 and was initially misdiagnosed with Guillain–Barré syndrome (GBS). Diagnostic evaluation included electrophysiological studies, biochemical assays for porphyrin precursors, and genetic testing. AIP was suspected based on electrophysiological findings and elevated porphyrin precursors. The patient improved after initiation of a 10% dextrose infusion and a high‐carbohydrate diet, with normalization of laboratory abnormalities. Subsequent genetic testing identified a heterozygous pathogenic HMBS variant (c.580C> T), confirming AIP. COVID‐19 may unmask AIP and mimic a GBS‐like neuropathy, increasing the risk of delayed recognition and suboptimal management. In patients with COVID‐19‐associated acute neuropathy—particularly when accompanied by abdominal pain, seizures, or neuropsychiatric features—clinicians should include AIP in the differential diagnosis and pursue prompt biochemical evaluation (urine PBG and ALA) to facilitate early targeted therapy and prevent complications.