Chronic malaria and hyper-reactive malarial splenomegaly: a retrospective study on the largest series observed in a non-endemic country.
BACKGROUND
Chronic malaria is usually defined as a long-term malarial infection in semi-immune subjects, usually without fever or other acute symptoms. The untreated infection may evolve to hyper-reactive malarial splenomegaly (HMS), a life-threatening complication. This paper describes the largest series of HMS ever observed outside endemic countries, and the clinical outcome after a single anti-malarial treatment. Contrarily to most authors, still reporting the traditional, long-term treatment, regardless possible further exposure, the patients in this series did not receive any further prophylaxis if they were not re-exposed to malaria infection.


METHODS
A retrospective, longitudinal study, describing all patients with HMS diagnosed at the Centre for Tropical Diseases of Negrar, Verona, took place over a 25-year period. HMS was defined by a longitudinal spleen diameter ≥16 cm, IgM ≥ 2.5 g/L, anti-malarial antibody titre ≥160, exclusion of other causes of splenomegaly. The short-term (≤6 months) clinical outcome after a single anti-malarial treatment was analysed and so was the long-term outcome of subjects re-exposed to malaria and submitted or not to anti-malarial prophylaxis or intermittent treatment. The association of the outcome with the main independent variables was first assessed with univariate analysis. Logistic regression was also performed.


RESULTS
Forty-four subjects with HMS were retrieved. Of those with a short-term follow-up visit (<6 months, median 43 days) available before returning to endemic areas, 20/22 resulted improved/cured, two were unchanged. Of 22 expatriates seen at long-term follow-up after re-exposure, 18 were improved/cured, including eight out of nine who had followed an anti-malarial prophylaxis and 10/13 who had opted for the alternative of an intermittent treatment.


CONCLUSIONS
HMS is the most severe form of chronic malaria. A single anti-malarial treatment is probably adequate to treat HMS in the absence of re-exposure, while an adequate prophylaxis is necessary for patients exposed again to malaria transmission. Intermittent treatment would probably be the only viable approach in endemic countries.
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy. zeno.bisoffi@sacrocuore.it.
Zeno
Z
Bisoffi
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Stefania
S
Leoni
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Andrea
A
Angheben
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Anna
A
Beltrame
Ospedale Dell'Angelo, Via Don Federico Tosatto, 147, 30174, Venezia Mestre, Italy.
Franklyn Esoka
FE
Eseme
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Federico
F
Gobbi
Medici Senza Frontiere Italia, Via Magenta 5, 00186, Rome, Italy.
Claudia
C
Lodesani
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Stefania
S
Marocco
Centre for Tropical Diseases, Sacro Cuore - Don Calabria Hospital, 37024, Negrar, Verona, Italy.
Dora
D
Buonfrate
D000328:Adult; D000368:Aged; D000962:Antimalarials / Q000627:therapeutic use*; D054242:Emigrants and Immigrants; D005260:Female; D006801:Humans; D007558:Italy; D008137:Longitudinal Studies; D008288:Malaria / Q000175:diagnosis / Q000188:drug therapy* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013163:Splenomegaly / Q000175:diagnosis / Q000188:drug therapy* / Q000469:parasitology
D000962:Antimalarials