‘SMALL SPLEEN’ OF MALARIA
Having read the excellent, first-rate editorial by Whitty CJM et al  about the everlasting problem of malaria, I am prompted to bring to your notice that in cases who have been afflicted by the P. falciparum malaria, the splenic size decreases to below normal . Similar decrease is evident in the residential population of P. falciparum endemic area , which I have also witnessed in certain real tall and stout healthy males as well of Northern Botswana.
This shrinkage of spleen following clinical falciparum malaria, as also with the sub-clinical infections (premonition) that go unnoticed in residential population provides certain amount of immunity to malaria. In a hospital setting, this ‘small spleen’ can be easily picked up by ultrasonography in 2 to 5 minutes . The smallest spleen noticed was of just 7.8 cm in a 30 year old healthy 68 kg adult male, who had a height of 1.71 m. Similarly this again was the smallest spleen size picked up in one of the adults from endemic malarial zone . The splenic size following P. vivax malaria also decreases, but not as significantly as with those having suffered clinical or sub-clinical episodes of P. falciparum malaria.
Once sickle cell disease is ruled out, if one were to find a ‘small spleen’ while dealing with malaria, it should be taken as a sign of acquired immunity for malaria. Given that malarial immunity is never complete, such individuals will require anti-malarial therapy, but the response shall be comparatively rapid and a lower total dose shall be required [3,4]. Individuals from endemic falciparum zones having a ‘small spleen’ would also not require anti-malarial prophylaxis . Travelers who have been infected once by P. falciparum malaria may similarly not require any prophylaxis while returning to an endemic zone, if they have a ‘small spleen’ [4,5]. Likewise in cases of rapid induction of troops, or in cases of mass relief operations, ultrasonography of spleen has the potential of detecting individuals who will not require anti-malarial prophylaxis, thus saving on costs and unwarranted side effects. The choice of anti-malarials to be used depends on the availability, cost versus adverse effects and the status of established drug resistance .
Dr. Rajesh Chauhan MBBS, DFM, FCGP, ADHA, FISCD, FAIMS. Consultant, Family Medicine & Communicable Diseases.
Dr. Akhilesh Kumar Singh. MBBS, MD.
Dr. Parul Kushwah. MBBS, MISMCD.
1. Whitty CJM, Ansah E, Reyburn H. Treating severe malaria. BMJ 2005;330:317-18.
2. Chauhan R, Kapoor V, Vohra PA, Jhala PJ, Upadhyaya AK, Pathak KJ.The 'Small Spleen' in Malaria. J Assoc Physicians India. 1996 Jul;44(7):483-85. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9282611
3. The Small Spleen: Harbinger of malarial immunity (an original study). Rajesh Chauhan, Grover H, Bora D, Chauhan P, Singh AK, Kushwah M. In: Joint Annual Conference of Indian Society for Malaria & other communicable diseases & Indian Association of Epidemiologists. 09-11 Nov 2002, SCOPE convention Centre New Delhi. Page 25. Abstract serial 2.8 at page 25.
4. Unique experience with ultrasonography in malaria- a pilot study. Chauhan R, Tilak VW, Chowdhary HS, Kapoor V. In: Joint Annual Conference of Indian Society for Malaria & other communicable diseases & Indian Association of Epidemiologists. 30 Oct – 01 Nov 1998, SCOPE convention Centre New Delhi. Abstract serial 45 at page 25.
5. Moore DAJ, Jennings RM, Doherty TF, Lockwood DN, Chiodini PL, Wright SG, et al. Assessing the severity of malaria. BMJ 2003; 326: 808- 09.
6. Baird JK. Effectiveness of Antimalarial Drugs. NEJM 2005; 352(15): 1565-77.
Competing interests: None declared
Competing interests: No competing interests