Thinking outside the cranium

Introduction Cerebral toxoplasmosis is a leading cause of central nervous system (CNS) lesions in severely immunocompromised human immunodeficiency virus+ (HIV+) patients who are seropositive for the parasite and have not received effective chemoprophylaxis. A 48-year-old HIV+ woman presented to our emergency room with seizure and decreased level of consciousness. She had developed fever, productive cough, and malaise 1 week prior to her current admission. Multifocal sensory and motor deficits in her extremities were revealed on neurologic examination. The brain imaging of our patient showed a distinctive ring-enhancing lesion that narrowed our differential diagnosis considerably. The patient was admitted on January 20, 2009 with decreased level of consciousness, urinary incontinence, upward eye deviation, right arm tonic flexion and right leg clonic jerks while the left extremities were tonically extended. Her seizure was controlled with intravenous diazepam and phenytoin, and she was fully conscious for history taking 5 h after presentation. The patient had a positive history for HIV infection and reported prolonged close contact with a known tuberculosis (TB) case 2 years ago. She had developed fever, productive cough and malaise 1 week prior to her current admission; CD4 count of 18 cells/μL, skin purified protein derivative reactivity of 5 mm and a negative sputum smear for acid-fast bacilli had been reported at the time waiting for culture results. She also complained of headaches and weight loss during the past month. Oral co-amoxiclav and co-trimoxazole were administered for her recent symptoms. For her HIV, she had received IMOD intermittently (for a total of 6 months) during the year prior to admission – Setarud (IMOD) is a herbal medicine prepared from a mixture of extracts of Rosa canina, Urtica dioica, and Tanacetumv ulgare in addition to selenium, flavonoids, and carotenes. Ten years ago, after a bout of jaundice, she had been diagnosed with acute hepatitis B. The resolution of which was documented with hepatitis B surface antigen clearance and hepatitis B surface antibody seroconversion at the time. Neurologic examination revealed multifocal sensory and motor deficits involving her left ulnar nerve distribution, right median nerve distribution, proximal and distal right lower extremity weakness and atrophy, and symmetric sensory deficits in both feet. The patient’s lab data during the past year revealed a steady decline in CD4 counts from 361 cells/μL in August 2007 and variable peripheral eosinophilia. The patient’s lab results during her admission are shown in table 1. Brain imaging showed a single ring-enhancing lesion in the left posterior parietal lobe (Figure 1). In developing countries, the differential diagnosis for a severely immunocompromised HIV+ patient with a solitary ring-enhancing brain lesion should include primary CNS lymphoma (PCNSL), TB, toxoplasmosis, neurocysticercosis, and much less commonly infections caused by Staphylococcus, Streptococcus, Salmonella, Aspergillus, Nocardia, Rhodococcus, Listeria, Cryptococcus, Treponemapallidum, and cytomegalovirus (CMV). The typical magnetic resonance finding in toxoplasmic encephalitis (TE) is that of multiple ringenhancing lesions with a predilection for basal ganglia; solitary lesions are reported in approximately 30% of cases.1 Single and multiple lesions are equally Iranian Journal of Neurology