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Título

Hystoplasma capsulatum: an unusual etiology of central nervous system vasculitis

RESUMO

Case Report: A 47-year-old woman who had been investigating Systemic Lupus Erythematosus (SLE) was admitted to the Emergency Room with acute onset right hemiparesis and hemihypoesthesia. Computed tomography scan showed a left thalamic hypodensity compatible with a subacute ischemic stroke, along with a lacunar ischemic lesion in the right internal capsule. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis, consumed glucose and elevated protein levels. The etiologies considered were autoimmune and infectious disorders. Exams to rule out the second one were negative. A cranial magnetic resonance imaging (MRI) showed more ischemic lesions and diffuse arterial narrowing. The rheumatology team considered active arthritis as well, so an autoimmune mechanism was considered the most likely. Due to progression of lesions and the potential gravity of this condition, she was submitted to a course of methylprednisolone and cyclophosphamide. Her initial response was good and she was discharged a few days later. After one week, she started with fever, a novel right-sided oculomotor nerve paresis and mental confusion. Cranial MRI showed recent ischemic events on the midbrain, pons and right cerebellar hemisphere. CSF analysis evidentiated worsening of the previous findings with a high opening pressure. A new screening for infectious causes was positive for histoplasmosis, with a counterimmunoelectrophoresis for Hystoplasma capsulatum titer of 1:16 on CSF and blood, with negative cultures. In view of the hypothesis of CNS histoplasmosis leading to vasculitis and ischemic strokes, antifungal treatment was started. She developed generalized seizures and progressive somnolence, with needing for orotracheal intubation. During her prolonged hospitalization, she had multiple infectious and clinical complications. Subsequent radiological studies and CSF analysis evidentiated poor improvement. Months later, she was discharged with many neurological sequelae, with a plan of prolonged oral antifungal treatment. Discussion: CNS vasculitis is rarely caused by SLE. Infectious causes must be remembered due to their prevalence, especially in immunocompromised patients. Our patient had radiologic findings previously described in CNS vasculitis caused by Hystoplasma, as the main involvement of small vessels of posterior circulation. However, sometimes it is necessary to ponder empirical immunosuppressive treatment because of clinical worsening and sequelae risks, like in our case.

Palavras Chave

Cerebrovascular disease; CNS vasculitis; Histoplasmosis.