To describe a case of area postrema syndrome as a neurological manifestation of antiphospholipid syndrome (APS).

Area postrema is known as a vomiting reflex center that lacks a blood-brain barrier, which facilitates the entry of anti-AQP4 antibodies into nervous tissue and triggering an inflammatory reaction in the central nervous system. Area postrema syndrome is a rare condition that can appear as an isolated clinical symptom within the spectrum of neuromyelitis optica spectrum disorder (NMOSD) in up to 30% of patients. However, this syndrome has other uncommon etiologies related to autoimmune diseases such as antiphospholipid syndrome (APS).

A 48-year-old Ecuadorian woman presented episodes of severe headache, intractable vomiting, and progressive paresthesia in her upper and lower extremities for two months. MRA was made, revealing a T2/FLAIR hyperintense lesion involving the area postrema, from the bulbo-medullary junction to C2, with dorsal and central distribution. Lumbar puncture analysis showed pattern 4 oligoclonal bands (serum and CSF) without pleocytosis or hypoglycorrhachia. Serology was negative for anti-AQP4 antibodies, excluding neuromyelitis optica spectrum disorder (NMOSD), and positive for anti-cardiolipin IgM (68.47) and lupus anticoagulant (1.24), consistent with antiphospholipid syndrome (APS). Methylprednisolone 1 g/day was administered for 5 days, followed by tapering prednisone. The patient responded favorably to high-dose corticosteroid therapy, with significant clinical improvement.

Commonly, gastrointestinal manifestations are linked to problems in the digestive tract and are not secondary to autoimmune/demyelinating diseases. In Ecuador, area postrema syndrome clinical manifestations are rare, which limits their clinical and radiological diagnosis. This case could represent the first area postrema syndrome associated with APS in our country.