Neurological disorders in Tanzania. Studies on HIV-I, Guillain-Barré syndrome and konzo
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This thesis is the result of clinical studies carried out in Northern Tanzania from 1984-1992 and reports on a number of new clinical entities. These are HIV related neurological disorders, konzo and new forms of existing diseases such as Guillain-Barre Syndrome (GBS). The first and second papers report that neurological disorders were amongst the most common (70%) disorder in AIDS. The Snout and Palmomental reflexes were the most common abnormal neurological finding and increased incrementally with advancing HIV stage and associated neurological disorders. The third paper investigates a consecutive series of GBS cases admitted to Kilimanjaro Christian Medical Centre (KCMC) and to Haukeland University hospital Western Norway and demonstrated that the incidence rate, epidemiological and main clinical fmdings apart from minor differences were similar in the two series. The increased mortality rate (15%) seen in the Tanzanian series is explained mainly by the lack of resources for adequate intensive care. An association between HIV infection and GBS was seen in the Tanzanian but not the Norwegian series and HIV positive GBS patients tended to have more severe neurological disease and increased mortality. The fourth and fifth papers are reports on field surveys in Tarime district in Northern Tanzania investigating an epidemic of unexplained spastic paraparesis which occurred in 1985. The studies showed that the disease is a distinct entity manifested by spastic paraparesis and characterized by a disorder which always affects the distal upper motor neurones to a greater extent than the proximal ones. The disease was named konzo, a local name from the first reported outbreak in Zaire (Trolli 1938). The prevalence of konzo in 15 villages studied ranged from zero cases in the lake shore villages to 1411000 in the inland villages only 5 km away. All patients gave a history of almost complete reliance on bitter cassava as a staple food in the months prior to and during the epidemic. This arose because of the widespread failure of other crops as a result of the severe drought in 1984. In addition the traditional processing methods used for removal of cyanogenic compounds from the roots of bitter cassava appeared to have been shortened. A resulting high cyanide exposure was supported by high serum thiocyanate levels, the mean SCN in May 1985 in 20 cases and 9 controls were 368 and 303 μmoles/l respectively. The geographic and temporal distribution of konzo was also shown to be compatible with cyanide exposure from insufficiently processed cassava roots and there was no evidence of an infectious aetiology. The sixth paper reports on specialized neurological investigations of two patients with konzo who were brought to Sweden which suggests that the site of the pathology in konzo is most probably situated centrally in the motor cortex rather than in the spinal cord.
Paper I: Howlett WP, Nkya WM, Mmuni KA, Missaleck WR. Neurological disorders in AIDS and HIV disease in the northern zone of Tanzania. AIDS 1989;3(5):289-298. PMID: 2504233. Full text not available in BORA due to publisher restrictions. The published version is available at: http://journals.lww.com/aidsonline/Abstract/1989/05000/Neurological_disorders_in_AIDS_and_HIV_disease_in.7.aspxPaper II: Howlett WP, Nkya WM, Kvåle G, Nilssen S. Frontal lobe release signs in HIV disease. Acta Neurol Scand 1995; in press. Published as: Howlett WP, Nkya WM, Kvåle G, Nilssen S. The snout and palmo-mental reflexes in HIV disease in Tanzania. Acta Neurol Scand. 1995 Jun;91(6):470-6. PMID: 7572042. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1111/j.1600-0404.1995.tb00448.xPaper III: Howlett WP, Vedeler CA, Nyland H, Aarli JA. Guillain-Barre syndrome in northern Tanzania: A comparison of epidemiological and clinical findings with western Norway 1994; submitted for publication. Published as: Howlett WP, Vedeler CA, Nyland H, Aarli JA. Guillain-Barré syndrome in northern Tanzania: a comparison of epidemiological and clinical findings with western Norway. Acta Neurol Scand. 1996 Jan;93(1):44-9. PMID: 8825272. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1111/j.1600-0404.1996.tb00169.xPaper IV: Howlett WP, Brubaker GR, Mlingi N, and Rosling H. Konzo an upper motor neurone disease studied in Tanzania. Brain 1990;113(1):223-235. PMID: 230253. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1093/brain/113.1.223Paper V: Howlett W, Brubaker GR, Mlingi N, and Rosling H. A geographical cluster of konzo in Tanzania. J Trop Geogr Neur 1992;2:102-108. The article is available at: http://hdl.handle.net/1956/6761Paper VI: Tylleskar T, Howlett W, Rwiza H, Aquilionius SM, Stålberg E, Lindén B, Mandahl A, Larsen H, Brubaker G and Rosling H. Konzo: a distinct disease entity with selective upper motor neurone damage. J Neurol Neurosurg Psychiat 1993;56(6):638-643. PMID: 850977. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1136/jnnp.56.6.638
PublisherThe University of Bergen
SubjectHIVAIDSNeurological disordersSnout reflexesPalmomental reflexesGuillain Barré syndromeKonzoSpastic paraparesis
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