This is a common disease in equatorial Africa and in Central and South America. There are two types; the African type (“sleeping sickness”) is caused by Trypanosoma brucei, rhodesiense, and gambiense and is transmitted by several species of the tsetse fly. The second type is Chagas disease, predominantly seen in South America. Most cases in the United States have been in travelers returning from African safari. There had been an alarming increase in trypanosomiasis in sub-Saharan Africa during past decades but now, fewer than several thousand cases have been reported because of active control interventions. The infection begins with a chancre at the site of inoculation and localized lymphadenopathy. Posterior cervical adenopathy is a characteristic feature of subsequent CNS infection (Winterbottom sign); another sign of neurologic interest is pronounced pain at sites of minor injury (called Kerandel hyperesthesia). Later, episodes of parasitemia occur, and at some time during this stage of dissemination, usually in the second year of the infection, the trypanosomes can give rise to a diffuse meningoencephalitis. The latter expresses itself clinically as a chronic progressive neurologic syndrome consisting of a reversal or disruption of circadian sleep rhythm (thus, “sleeping sickness”), vacant facial expression, and in some, ptosis and ophthalmoplegia, dysarthria, and then muteness, seizures, progressive apathy, stupor, and coma.
The South American variety of trypanosomiasis (Chagas disease) is caused by Trypanosoma cruzi and is transmitted from infected animals to humans by the bite of reduviid bugs. There have been rare cases from blood transfusion and organ transplantation. The sequence of local lymphadenopathy, hematogenous dissemination, and chronic meningoencephalitis is like that of
African trypanosomiasis. There are, of course, numerous other aspects to Chagas disease, including esophageal and colonic motility disorders and cardiac disease. In immunosuppressed hosts, particularly with HIV, the presentation may include meningoencephalitis and brain abscess. Patients undergoing immunosuppression for organ transplantation may have reactivation of the infection. Serologic tests are available to confirm the diagnosis.
Treatment Treatment in the past was with pentavalent arsenicals, mainly melarsoprol, which were more effective in the African than in the South American form of the disease, but is toxic. (It is of historical interest that a search for trypanosomal agents led Ehrlich to the “magic bullet” of pentavalent phenolic arsenic-Salvarsan-that was the first truly effective treatment for syphilis). An encephalopathy occurred in 10 percent of cases during the institution of arsenical treatment; half of these are fatal. As pointed out by Braakman and colleagues, the arsenical encephalopathy is characterized by multiple white matter lesions, sometimes with hemorrhage, and is often quite severe and in those cases, lethal in between 50 and 75 percent. Newer drugs or combinations, particularly eflornithine with nifurtimox are being used for the gambiense disease. Currently, pentamidine and suramin are used for early stages of the African form but is less effective if there are nervous system manifestations. The treatment of Chagas disease is with nifurtimox, a nitrofurantoin, and benznidazole, a nitroimidazole derivative. A review of the subject of trypanosomiasis has been given by Kennedy and of Chagas disease specifically, by Bern.
Of these, trichinosis is of greatest importance to neurologists. Infections with other roundworms, such as Angiostrongylus, cause an eosinophilic meningitis, as discussed further on.
Trichinellosis, Trichinosis (See Also Chap. 45)
This disease is caused by the intestinal nematode