P olyarteritis nodosa (PAN) is a multisystem disease characterized by necrotizing vasculitis involving small and mediumsized arteries. Varied clinical features result from the variable distribution of the arterial lesions (1, 2). Neurologic manifestations are common, particularly peripheral neuropathy, which occurs in 50% to 70% of patients. Central nervous system (CNS) involvement, which appears less frequently (in 8% to 40% of cases), is an important cause of morbidity and mortality (3, 4). The differential diagnosis of vasculitis affecting the CNS involves a broad range of diseases, including infections and malignancies. Thus, diagnosis and management of CNS manifestation in systemic vasculitis may represent a challenge for the critical care physician. We report a case of PAN with CNS involvement mimicking infectious meningoencephalitis.
CASE REPORTA 9-yr-old boy was referred to our hospital with a 13-day history of fever and headache. Five days before admission, he experienced fatigue, cough, and dyspnea accompanied by transient arthralgia and skin rash. Over the next days, he presented with vomiting and diplopia. Then 24 hrs before transfer to the pediatric intensive care unit, the boy became confused and drowsy. He had a history of intermittent fever and abdominal pain since 3 yrs of age.At admission, the patient's blood pressure was 110/50 mm Hg. He was tachycardic (heart rate, 115 beats/min) and tachypneic (respiratory rate, 56 breaths/ min), and hepatosplenomegaly was noted. His neurologic examination showed a decreased level of consciousness (Glasgow Coma Scale, 13), neck stiffness, and right papilledema. Laboratory investigations showed a hemoglobin level of 10.7 g/dL, platelets of 94,000/ mm 3 , white blood cell (WBC) count of 15,600/mm 3 (1% bands, 84% neutrophils, 15% lymphocytes), and C-reactive protein of 23 mg/dL. Chest radiography showed a right pleural effusion and diffuse interstitial pulmonary infiltrates. The echocardiogram demonstrated pericardial thickening and a small pericardial effusion. Computed tomographic scan of the brain showed a hypodensity on the right posterior temporal lobe. Cerebrospinal fluid (CSF) examination showed 144 WBC/mm 3 (89% neutrophils), 3 red blood cells/mm 3 , protein 99 mg/dL, glucose 49 mg/dL, and chloride 117 mmol/L. The electroencephalogram was diffusely abnormal, with increased slow activity.A diagnosis of infectious meningoencephalitis was determined, and the patient was treated with antibiotic (ceftriaxone). However, an infectious origin was not confirmed. Cultures of blood and CSF for bacteria, mycobacteria, and fungi yielded negative results. The results of CSF latex particle agglutination for Neisseria meningitis, Streptococcus pneumoniae, and Haemophilus influenzae also were negative. Blood and CSF serology for histoplasmosis, cryptococcosis, paracoccidioidomycosis, aspergillosis, candidiasis, Chagas disease, toxoplasmosis, cysticercosis, syphilis, and herpesvirus yielded negative results. Blood polymerase chain reaction for parvovirus and CSF polymera...
