Acute Hemorrhagic Leukoencephalitis in Pregnancy

A 27-year-old pregnant woman at 18 weeks of gestation presented with a one-week history of fever, slurred speech, and a generalized tonic-clonic seizure. There was no antecedent prodromal illness, sick contacts, or known precipitating event; fever and neurological symptoms developed simultaneously. Examination revealed global aphasia, spastic quadriparesis, and bilateral extensor plantar responses.

Magnetic resonance imaging of the brain showed multifocal, confluent hyperintensities on T2-weighted and fluid-attenuated inversion recovery sequences involving both cerebral hemispheres, thalamus, midbrain, and pons (Figure 1A and B). Susceptibility-weighted imaging revealed multiple punctate microhemorrhages (Figure 1C, arrows). Cerebrospinal fluid revealed 12 lymphocytes/μL, elevated protein (100 mg/dL), and normal glucose (60 mg/dL). Workup for autoimmune conditions, including oligoclonal bands and aquaporin-4 antibodies, as well as viral and other infectious etiologies, yielded negative results.OPEN IN VIEWER

These findings were diagnostic of acute hemorrhagic leukoencephalitis (AHLE), a hyperacute, necrotizing form of acute disseminated encephalomyelitis, characterized by rapid neurologic deterioration, multifocal deficits, and extensive demyelination with hemorrhagic necrosis.^1,2 AHLE is more frequently reported in males and is often associated with a preceding infection or immunologic trigger. ² In this case, however, no specific precipitant was identified. The patient was treated with high-dose intravenous methylprednisolone (1 gram daily for five days), followed by a tapering course of oral corticosteroids over six weeks. She showed marked neurological recovery, remained asymptomatic at one-year follow-up, and delivered a healthy full-term infant.

This case illustrates the classic imaging features of AHLE—a rare but life-threatening demyelinating syndrome. Early recognition and immunosuppressive therapy are crucial for favorable outcomes. In pregnant patients with acute encephalopathy and hemorrhagic brain lesions, AHLE should be considered as a differential diagnosis, alongside more common conditions such as posterior reversible encephalopathy syndrome and cerebral venous sinus thrombosis, even in the absence of an identifiable trigger.