Medscape is available in 5 Language Editions – Choose your Edition here.


Tropical Splenomegaly Syndrome

  • Author: Mundeep K Kainth, DO, MPH; Chief Editor: Robert J Arceci, MD, PhD  more...
Updated: Oct 09, 2015


Several reports were published over the last century describing patients from tropical areas with massive splenomegaly. After excluding known causes of splenomegaly, tropical splenomegaly syndrome was defined as a separate entity.[1, 2, 3] This condition was later defined as hyperreactive malarial syndrome (HMS) using clear diagnostic criteria.[4, 5]

See the image below.

Young patient with hepatomegaly and massive spleno Young patient with hepatomegaly and massive splenomegaly.


Hyperreactive malarial syndrome (HMS) is prevalent in native residents of regions where malaria is endemic and visitors to those regions. Patients with HMS have high levels of antibody for Plasmodium falciparum, Plasmodium vivax, or Plasmodium ovale.[6] Chronic antigenic stimulation may be an important factor in the development of HMS.

Although the exact mechanism is uncertain, evidence suggests that repeated or chronic exposure to malaria elicits exaggerated stimulation of polyclonal B lymphocytes, leading to excessive and partially uncontrolled production of immunoglobulin M (IgM) as the initiating event.[7] IgM is polyclonal and is not specific for any particular malarial species.

Genetic factors, pregnancy, and malnutrition may also play a role in the etiology of HMS. Relative protection against HMS is observed in patients with sickle cell trait, as it is with malaria. In experimental models, animals developed a similar syndrome after malarial infection.

Defective immunoregulatory control of B lymphocytes by suppressor or cytotoxic T lymphocytes causes the increase in B lymphocytes, although the mechanism by which malarial parasitemia drives these changes is unclear.[8] T-cell infiltration of the hepatic and splenic sinusoids accompanies this process. Serum cryoglobulin and autoantibody levels increase, as does the presence of high-molecular-weight immune complexes. The result is anemia, deposition of large immune complexes in Kupffer cells in the liver and spleen, reticuloendothelial cell hyperplasia, and hepatosplenomegaly. Plasma levels of interleukin 10 (IL-10) and interferon gamma (IFNγ) are significantly increased.[9]

Effective malarial chemoprophylaxis and eradication measures have been associated with a decrease in the incidence of HMS. Antimalarial treatment is shown to be effective in decreasing splenomegaly, correcting anemia and lymphocytosis, and decreasing serum IgM in patients with HMS. However, withdrawal of prophylaxis in patients from malaria-endemic regions has been associated with relapse anywhere from 2-18 months after initial diagnosis.[10]




United States

Hyperreactive malarial syndrome (HMS) has been reported only in people who have resided in or who have visited areas where malaria is endemic.[11]


Hyperreactive malarial syndrome (HMS) is restricted to native residents and visitors of the malaria belt, which roughly encompasses equatorial regions of South America, Africa, the Middle East, South Asia, and Southeast Asia.

HMS has been reported in Algiers, Congo, Madagascar, Ivory Coast, Sudan, New Guinea, Nigeria, India, Philippines, Brazil, China, Uganda, Yemen, Bangladesh, Ethiopia, Hong Kong, Ghana, Somalia, Zambia, and Chile. The incidence of HMS is highest among the people of the Upper Watut Valley in Papua New Guinea, where the rate is estimated to be 80%.[12]

Accurate assessment of the incidence of HMS is difficult because many conditions that cause splenomegaly are prevalent in areas where malaria is endemic. These conditions include hemoglobinopathies, lymphoreticular disorders, schistosomiasis, hepatic cirrhosis, leishmaniasis, typhoid, and tuberculosis.

The incidence of massive splenomegaly is estimated to be 1-2% in rural Nigeria,[1] and HMS accounts for 11-45% of massive splenomegaly cases in Africa.[13]

In a review of patients with massive splenomegaly in Ghana, 41% were diagnosed to have HMS; the rate in Sudan was 9%.[9] The second most common diagnosis was B-lymphoproliferative disorders. Even with relatively modern investigative techniques, no diagnosis could be established in about a fourth (23%) of the patients. HMS was associated with a younger age, female sex, and lower absolute lymphocyte counts than lymphoproliferative disorders.[14]


The natural history of hyperreactive malarial syndrome (HMS) is not well documented. HMS is associated with a high mortality rate in untreated individuals; overwhelming infections are the leading cause of death. A 5-year mortality rate of 50% was reported in Uganda and New Guinea,[15] with a mortality of 85% in hospitalized patients.[6] However, other series found a much lower mortality rate.[16]

HMS is not a premalignant condition, although an overlap with chronic lymphocytic leukemia has been noted.[17] Whether HMS can undergo clonal evolution to splenic lymphoma with villous lymphocytes (SLVL) is unclear; these entities appear to evolve independently in response to chronic antigen stimulation.

HMS has also been documented in immunocompromised patients from malaria-endemic regions who have HIV infection and lung carcinoma, following the exclusion of other disease entities, such as Epstein-Barr virus, cytomegalovirus, or lymphoproliferative disorders.[18, 19]


Generally, the distribution of malaria in the tropical areas of the world also predisposes individuals of certain racial origin such as African American, Asian, and Pacific Islander to hyperreactive malarial syndrome (HMS).

Inheritance of a genetic trait in individuals who develop HMS has also been described. Interestingly, X-linked segregation implicated in the pathogenesis of HMS tends to present with strong familial patterns that have been identified in residents of Papua New Guinea, but not Ghana.[11, 20]

Furthermore, a genetic component of the immune response implicated in HMS has been described. Specifically, less heterozygosity of human lymphocyte antigens (HLAs) has been hypothesized to be associated with a less robust immune response to recurrent malaria infection than in individuals with more heterozygous HLA.[21]

HMS has been reported in whites who resided in or moved to areas where malaria was endemic. It has also been described among visitors who received inadequate prophylaxis against malaria.[22]


Overall, hyperreactive malarial syndrome (HMS) is more common in females, especially lactating mothers, than in males, with a female-to-male ratio of 2:1. Only one study in Eastern Sudan showed men to have a higher incidence.[23]


Hyperreactive malarial syndrome (HMS) is most common in young and middle-aged adults, although the process probably commences during childhood. HMS is rare in children younger than 8 years but was reported in a 3-year-old patient.[24]

Contributor Information and Disclosures

Mundeep K Kainth, DO, MPH City Medical Specialist, Bureau of School Health, Division of Family and Child Health, New York City Department of Health and Mental Hygiene; General Pediatrician, Island Pediatric Associates

Mundeep K Kainth, DO, MPH is a member of the following medical societies: American Academy of Pediatrics, Infectious Diseases Society of America, Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.


Mudra Kumar, MD, MRCP, FAAP Professor of Pediatrics, Course Director, Course 6 MSII, Preclerkship Director, Clinical Integration, Department of Pediatrics, University of South Florida Morsani College of Medicine

Mudra Kumar, MD, MRCP, FAAP is a member of the following medical societies: American Academy of Pediatrics, American Society of Hematology, American Society of Pediatric Hematology/Oncology

Disclosure: Nothing to disclose.

Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP Professor of Pediatrics, Albany Medical College; Chief, Division of Pediatric Hematology-Oncology, John and Anna Landis Endowed Chair for Pediatric Hematology-Oncology, Medical Director, Melodies Center for Childhood Cancer and Blood Disorders, Albany Medical Center

Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP is a member of the following medical societies: American Academy of Pediatrics, American Society of Hematology, American Society of Pediatric Hematology/Oncology, Children's Oncology Group, International Society of Pediatric Oncology

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

James L Harper, MD Associate Professor, Department of Pediatrics, Division of Hematology/Oncology and Bone Marrow Transplantation, Associate Chairman for Education, Department of Pediatrics, University of Nebraska Medical Center; Associate Clinical Professor, Department of Pediatrics, Creighton University School of Medicine; Director, Continuing Medical Education, Children's Memorial Hospital; Pediatric Director, Nebraska Regional Hemophilia Treatment Center

James L Harper, MD is a member of the following medical societies: American Society of Pediatric Hematology/Oncology, American Federation for Clinical Research, Council on Medical Student Education in Pediatrics, Hemophilia and Thrombosis Research Society, American Academy of Pediatrics, American Association for Cancer Research, American Society of Hematology

Disclosure: Nothing to disclose.

Chief Editor

Robert J Arceci, MD, PhD Director, Children’s Center for Cancer and Blood Disorders, Department of Hematology/Oncology, Co-Director of the Ron Matricaria Institute of Molecular Medicine, Phoenix Children’s Hospital; Editor-in-Chief, Pediatric Blood and Cancer; Professor, Department of Child Health, University of Arizona College of Medicine

Robert J Arceci, MD, PhD is a member of the following medical societies: American Association for the Advancement of Science, American Association for Cancer Research, American Pediatric Society, American Society of Hematology, American Society of Pediatric Hematology/Oncology

Disclosure: Nothing to disclose.

Additional Contributors

J Martin Johnston, MD Associate Professor of Pediatrics, Mercer University School of Medicine; Director of Hematology/Oncology, The Children's Hospital at Memorial University Medical Center; Consulting Oncologist/Hematologist, St Damien's Pediatric Hospital

J Martin Johnston, MD is a member of the following medical societies: American Academy of Pediatrics, American Society of Pediatric Hematology/Oncology, International Society of Paediatric Oncology

Disclosure: Nothing to disclose.

  1. Pitney WR. The tropical splenomegaly syndrome. Trans R Soc Trop Med Hyg. 1968. 62(5):717-28. [Medline].

  2. Bryceson A, Fakunle YM, Fleming AF, et al. Malaria and splenomegaly. Trans R Soc Trop Med Hyg. 1983. 77(6):879. [Medline].

  3. Fakunle YM. Tropical splenomegaly. Part 1: Tropical Africa. Clin Haematol. 1981 Oct. 10(3):963-75. [Medline].

  4. Facer CA, Crane GG. Hyperreactive malarious splenomegaly. Lancet. 1991 Jul 13. 338(8759):115-6. [Medline].

  5. Bates I, Bedu-Addo G. Review of diagnostic criteria of hyper-reactive malarial splenomegaly. Lancet. 1997 Apr 19. 349(9059):1178. [Medline].

  6. Crane GG. Hyperreactive malarious splenomegaly (tropical splenomegaly syndrome). Parasitol Today. 1986 Jan. 2(1):4-9. [Medline].

  7. Hoffman SL, Piessens WF, Ratiwayanto S, et al. Reduction of suppressor T lymphocytes in the tropical splenomegaly syndrome. N Engl J Med. 1984 Feb 9. 310(6):337-41. [Medline].

  8. Piessens WF, Hoffman SL, Wadee AA, et al. Antibody-mediated killing of suppressor T lymphocytes as a possible cause of macroglobulinemia in the tropical splenomegaly syndrome. J Clin Invest. 1985 Jun. 75(6):1821-7. [Medline]. [Full Text].

  9. Alkadarou T, Musa A, Alkadarou A, Mahfouz MS, Troye-Blomberg M, Elhassan AM. Immunological characteristics of hyperreactive malarial splenomegaly syndrome in sudanese patients. J Trop Med. 2013. 2013:961051. [Medline].

  10. David-West AS. Relapses after withdrawal of proguanil treatment in tropical splenomegaly syndrome. Br Med J. 1974 Aug 24. 3(5929):499-501. [Medline].

  11. Singh RK. Hyperreactive malarial splenomegaly in expatriates. Travel Med Infect Dis. 2007 Jan. 5(1):24-9. [Medline].

  12. Pryor DS. Tropical splenomegaly in New Guinea. Q J Med. 1967 Jul. 36(143):321-36. [Medline].

  13. Lowenthal MN, Hutt MS, Jones IG, Mohelsky V, O'Riordan EC. Massive splenomegaly in Northern Zambia. I. Analysis of 344 cases. Trans R Soc Trop Med Hyg. 1980. 74(1):91-8. [Medline].

  14. Wu YH, Chuang SY, Hong WC, Lai YJ, Chang YL, Pang JH. In vivo and in vitro inhibitory effects of a traditional Chinese formulation on LPS-stimulated leukocyte-endothelial cell adhesion and VCAM-1 gene expression. J Ethnopharmacol. 2012 Mar 6. 140(1):55-63. [Medline].

  15. Crane GG, Wells JV, Hudson P. Tropical splenomegaly syndrome in New Guinea. I. Natural history. Trans R Soc Trop Med Hyg. 1972. 66(5):724-32. [Medline].

  16. Fakunle YM, Greenwood BM. Mortality in tropical splenomegaly syndrome. Trans R Soc Trop Med Hyg. 1980. 74(3):419. [Medline].

  17. Bates I, Bedu-Addo G, Bevan DH, Rutherford TR. Use of immunoglobulin gene rearrangements to show clonal lymphoproliferation in hyper-reactive malarial splenomegaly. Lancet. 1991 Mar 2. 337(8740):505-7. [Medline].

  18. De Iaco G, Saleri N, Perandin F, et al. Hyper-reactive malarial splenomegaly in a patient with human immunodeficiency virus. Am J Trop Med Hyg. 2008 Feb. 78(2):239-40. [Medline].

  19. Foca E, Zulli R, Buelli F, De Vecchi M, Regazzoli A, Castelli F. P. falciparum malaria recrudescence in a cancer patient. Infez Med. 2009 Mar. 17(1):33-4. [Medline].

  20. Martin-Peprah R, Bates I, Bedu-Addo G, Kwiatkowski DP. Investigation of familial segregation of hyperreactive malarial splenomegaly in Kumasi, Ghana. Trans R Soc Trop Med Hyg. 2006 Jan. 100(1):68-73. [Medline].

  21. Bhatia KK, Crane GG. HLA heterozygosity and hyperreactive malarious splenomegaly in the Upper Watut Valley of Papua New Guinea. P N G Med J. 1989 Dec. 32(4):277-86. [Medline].

  22. Van den Ende J, van Gompel A, van den Enden E, Taelman H, Vanham G, Vervoort T. Hyperreactive malaria in expatriates returning from sub-Saharan Africa. Trop Med Int Health. 2000 Sep. 5(9):607-11. [Medline].

  23. Allam MM, Alkadarou TA, Ahmed BG, et al. Hyper-reactive Malarial Splenomegaly (HMS) in malaria endemic area in Eastern Sudan. Acta Trop. 2008 Feb. 105(2):196-9. [Medline].

  24. Verma S, Aggarwal A. Hyper-reactive malarial splenomegaly: rare cause of pyrexia of unknown origin. Indian J Pediatr. 2007 Apr. 74(4):409-11. [Medline].

  25. Mitjà O, Hays R, Malken J, et al. HMS-related hemolysis after acute attacks of Plasmodium vivax malaria. Am J Trop Med Hyg. 2011 Oct. 85(4):616-8. [Medline]. [Full Text].

  26. Bradaschia-Correa V, Barrence FA, Ferreira LB, Massa LF, Arana-Chavez VE. Effect of alendronate on endochondral ossification in mandibular condyles of growing rats. Eur J Histochem. 2012 May 25. 56(2):e24. [Medline]. [Full Text].

  27. Mothe B, Lopez-Contreras J, Torres OH, Munoz C, Domingo P, Gurgui M. A case of hyper-reactive malarial splenomegaly. The role of rapid antigen-detecting and PCR-based tests. Infection. 2008 Mar. 36(2):167-9. [Medline].

  28. Centers for Disease Control and Prevention. Malaria Diagnosis & Treatment in the United States. Available at Accessed: March 12, 2013.

  29. Leoni S, Buonfrate D, Angheben A, Gobbi F, Bisoffi Z. The hyper-reactive malarial splenomegaly: a systematic review of the literature. Malar J. 2015 Apr 29. 14:185. [Medline].

  30. Manenti F, Porta E, Esposito R, Antinori S. Treatment of hyperreactive malarial splenomegaly syndrome. Lancet. 1994 Jun 4. 343(8910):1441-2. [Medline].

  31. Aponte JJ, Aide P, Renom M, et al. Safety of the RTS,S/AS02D candidate malaria vaccine in infants living in a highly endemic area of Mozambique: a double blind randomised controlled phase I/IIb trial. Lancet. 2007 Nov 3. 370(9598):1543-51. [Medline].

  32. Agnandji ST, Lell B, Fernandes JF, Abossolo BP, Methogo BG. A phase 3 trial of RTS,S/AS01 malaria vaccine in African infants. N Engl J Med. 2012 Dec 13. 367(24):2284-95. [Medline].

Young patient with hepatomegaly and massive splenomegaly.
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.