Opportunistic infections are commonly detected in patients with Acquired Immuno-Deficiency Syndrome (AIDS). The most common infective pathogen accounting for focal brain lesions in AIDS patients is Toxoplasma gondii. However, due to the lack of an adequate immune system, other pathogens must be considered along with a complete assessment of the patient’s social history when making a diagnosis.
38 year old Honduran woman with no known medical history was admitted to the hospital after presenting to the emergency department with progressive right-sided hemiparesis, myalgias and headache. Computed tomography (CT) scan of the head showed areas of vasogenic edema in the left fronto-parietal and right parietal regions. Due to the concern for an infectious process a lumbar puncture was performed. The opening pressure was 11 cm of water, with 83 red blood cells, no white blood cells, glucose of 45 mg/dl, total protein of 29.2 mg/dl and negative microbiological studies and stains. Human Immunodeficiecy Virus (HIV) testing was positive with a subsequent CD4 count of 104 cells/mm3. Magnetic resonance imaging (MRI) of the head revealed numerous bilateral ring-enhancing lesions with necrotic centers with the largest measuring approximately 4 × 2.8 cm. Testing for Toxoplasma IgG and IgM, Crytococcus neoformans antigen, Histoplasma capsulatum antigen, Herpes Simplex Virus, Cytomegalovirus and Acid-fast bacilli (AFB) were all negative. Neurosurgery was consulted and the patient was then taken to the operating room for a brain biopsy. Additional stains were performed on the brain biopsy included for EBV (Epstein-Barr virus), AFB and cryptosporidium. The preliminary result communicated from pathology was consistent with Histoplasmosis, but more stains were needed due to atypical morphology and large amount of organisms seen. Following the brain biopsy the patient suffered a seizure and was transferred to the medical intensive care unit for management of cerebral edema and possible herniation. The patient was endotracheally intubated and placed on mechanical ventilation for airway protection and hyperventilation. Repeat CT of the head at that time showed no evidence of herniation but significant progression of the lesions. Final pathology results revealed necrotizing encephalitis with abundant organsisms consistent with Trypanosoma cruzi, which was confirmed by the Centers of Disease Control. The patient was then started on nifurtimox. The patient was eventually weaned off the ventilator and extubated. Subsequent repeat CT of the head showed stability of the lesions and mild improvement of the cerebral edema. The patient was transferred back to the medicine ward, but remained non-communicative with no improvement in mental status or hemiparesis.
Our patient’s presentation appeared consistent with cerebral toxoplasmosis, especially in the setting of undiagnosed HIV/AIDS. However, because progressive hemiparesis is not typical of toxoplasmosis, along with an otherwise negative work-up, a brain biopsy was required to make the final diagnosis of cerebral trypanosomiasis. Seropositivity for trypanosomal infection is well known among the people of endemic regions. Among immigrants from endemic regions there is high seroprevalence of chronic Chagas without clinical symptoms. Among 205 Central American immigrants in the Washington D.C. area tested between 1984–1985, 4.9% were infected with T. cruzi and parasites were isolated in 50% of attempted xenodiagnostic analysis. Although cardiac and gastrointestinal involvement are the main manifestations in the general population, cerebral infection is a well documented site for reactivation of chronic disease among the immuno-compromised patients, specifically those with AIDS.
Cerebral toxoplasmosis continues to be the most common infectious cause in AIDS patients with a cerebral lesion. In endemic patients, Trypanosmiasis must be considered and tested for as a possible causative agent when more common tests are non-diagnostic.
Alberto Colomer, No Financial Disclosure Information; No Product/Research Disclosure Information