Snapshot A 56-year-old nurse is brought to the emergency room for altered mental status. She spent a year in West Africa volunteering at a hospital. She returned to the US about 4 weeks ago. At that time, she had intermittent fevers with general malaise and a transient urticarial rash and noted a bug bite on her right forearm. She was then treated for malaria, though diagnostic testing was equivocal. In the past week, she became increasingly somnolent during the day. She also lost 15 lbs within the past 2 weeks. A lumbar puncture is done and diagnostic studies are sent. Meanwhile, she is started on empiric therapy. (African sleeping syndrome caused by Trypanosoma brucei) Introduction Protozoa single-celled eukaryotes, often parasitic, that feed on organic tissues Infections of Protozoa Central Nervous System Gastrointestinal Visceral Infections Hematologic Infections Sexually Transmitted Diseases Toxoplasma gondii Naegleria fowleri Trypanosoma brucei Acanthamoeba Giardia lamblia Entamoeba histolytica Cryptosporidium Trypanosoma cruzi Leishmania donovani Plasmodium Babesia Trichomonas vaginalis Toxoplasma gondii Introduction clinical syndrome toxoplasmosis reservoirs domestic cats transmission ingestion of cysts in meat ingestion of food contaminated with oocysts from cat excretion can be transmitted via placenta to neonate congenital toxoplasmosis triad of chorioretinitis, hydrocephalus, and intracranial calcifications pathogenesis tachyzoites are rapidly reproductive and invasive cysts are slow-dividing and latent, arising 1 week after infection can remain in hosts for a lifetime in the CNS oocysts contain sporozoites, can spread them to other hosts, and can survive in the environment for up to a year risk factors exposure to cats Presentation immunocompetent patients mononucleosis-like syndrome immunosuppressed patients brain abscesses focal neurologic deficits including aphasia, hemiparesis, and seizures Imaging and studies serologic detection of immunoglobulins with enzyme linked immunosorbent assay (ELISA) microscopy showing tachyzoites in blood or cerebral spinal fluid (CSF) brain MRI multiple ring-enhancing lesions Treatment sulfadiazine and pyrimethamine immunosuppressed patients Naegleria fowleri Introduction clinical syndrome meningoencephalitis risk factors swimming in warm freshwater pathogenesis protozoa enters the CNS via cribriform plate prognosis fatal in majority of cases within 1 week Presentation sudden headache photophobia and stiff neck altered sense of taste or smell nose bleeds altered mental status Imaging and studies cerebral spinal fluid presence of motile trophozoites elevated pressure culture and direct fluorescence antibody stain brain CT obliteration of cisternae and subarachnoid spaces Treatment amphotericin B Trypanosoma brucei Introduction clinical syndrome African sleeping sickness or African trypanosomiasis transmission via tsetse fly bite demographics endemic to sub-Saharan Africa prognosis good prognosis if treated appropriately Presentation early stage chancre at bite site intermittent fevers, malaise, myalgia, and arthralgia lymphadenopathy facial edema transient rash (urticarial or macular) 2 months after onset late stage persistent headaches daytime somnolence and nighttime insomnia (African sleeping sickness) weight loss Imaging and studies peripheral blood smear with trypomastigotes card agglutination test for trypanosomiasis (CATT) results available immediately high sensitivity (96%) lymph node biopsy CSF studies visualization of trypanosome detection of immunoglobulins Treatment suramin for early stage disease melarsoprol for late stage disease or CNS involvement Acanthamoeba Introduction clinical syndrome granulomatous amoebic encephalitis risk factors immunosuppression transmission via nasopharyngeal or breaks in skin pathogenesis cysts are dormant and resistant to treatment trophozoites are infective and replicate via fission prognosis high rate of mortality Presentation headache photophobia and stiff neck altered mental status skin lesions ulcers, nodules, or abscesses Imaging and studies cerebral spinal fluid presence of amoebas elevated pressure brain CT nonspecific findings of single or multiple low-density masses with hydrocephalus brain or skin biopsy granulomas, necrosis, amoebas, and inflammatory infiltrates Treatment no first-line treatment is recommended a combination of antibiotics and antifungals are usually used Complications residual vision or hearing impairment