A comparative study of intradermal smear in the diagnosis of malaria in symptomatic pregnant women.Venous blood served as the control.Fifty consecutive symptomatic pregnant women were recruited. Thick films of both venous and intradermal blood were examined. Questionnaires were used to determine patients' preference for the two techniques. Tests of statistical significance were done with Fisher exact and Yates correlationcoefficient at 95% confidence interval. Sensitivity, specificity and accuracy rates were used to assess the validity of intradermal smear.Intradermal smear more frequently diagnosed malaria parasitaemia than peripheral venous blood (66% vs 56%). This was statistically significant (P value: 0.0065). The sensitivity of intradermal smear was 85.7% while the positive predictive value was 77.4%. The accuracy rate was 76.7%. The technique of intradermal blood collection was preferred by28%of women.Intradermal smear is useful in malaria diagnosis in pregnancy and may be an additional evaluation tool for persistent fever in pregnancy

Eigbefoh, JO

Inyang, NJ

Ohiosimuan, O

Okpere, EE

Okusanya, BO

English

AJOL - African Journals Online

INTRODUCTIONMalaria is a common medical complication ofpregnancy in malaria endemic zones of the worldwhere about 40% of the world's population lives .Pregnant women are generally known to have anincreased susceptibility as well as a more severe formof the infection . A relative decline in immunity hasbeen adduced for this susceptibility.Malaria causes abortion, anaemia, preterm labour,intrauterine growth restriction and intrauterine fetaldeath . Congenital malaria has also been reportedin neonates .The relative decline in immunity to malaria inpregnant women causes an increased parasitaemia aswel l as c l in ica l d isease . Also , Humanimmunodeficiency virus (HIV) infection diminishesa pregnant woman's ability to control P. falciparuminfection . The prevalence and intensity of malariainfection during pregnancy is higher in women whoare HIV infected .Peripheral blood film (PBF) microscopy is the goldstandard in the diagnosis of malaria. Although rapiddiagnostic tests have been used, the variablesensitivity and specificity is a limiting factor in theiruse .12,3(2,4-7)89910,11Correspondence: Dr B OkusanyaE-mail: babakusanya@yahoo.co.ukThere are also instances when peripheral blood isnegative for malaria parasites in women who presentwith clinical symptoms of malaria. This isparticularly common in areas where there isunsupervised use of antimalaria drugs thereby posingmanagement dilemma .In these situations intradermal smear (IDS) may beuseful. Intradermal blood smear microscopy for thedetection of malaria pigments has been used albeit instudies involving non-pregnant patients. In malaria,parasitized red blood cells become more irregular inshape, more antigenic and less deformable causingcytoadherence to vascular endothelium. This leads tosequestration of parasitized red cells, blockage ofdeep vascular beds and mechanical blockage ofvessels .Intradermal blood smear has demonstrated a highsensitivity and specificity . This is due to thesequestration of malaria parasites in thesubcutaneous tissue. Dermal smear or biopsy showeda higher concentration of malaria parasites comparedto venous and capillary blood film due tosequestration and also, parasitaemia persisted insubcutaneous tissue in women with a negative venousblood suggesting that intradermal smear test may beuseful . Macpherson et al also suggested that skinsmears or biopsy would more accurately represent the12131313 13Nigerian Journal of Clinical PracticeDec. 2010 Vol. 13(4):427-430COMPARATIVE STUDY OF INTRADERMAL SMEAR MICROSCOPY IN THEDIAGNOSIS OF MALARIA IN SYMPTOMATIC PREGNANT WOMEN*BOOkusanya, **JO Eigbefoh, ***EEOkpere, ****OOhiosimuan, *****NJ InyangABSTRACTObjectives:Patients and methods :Results:Conclusion:Key WordsA comparative study of intradermal smear in the diagnosis of malaria in symptomatic pregnantwomen. Venous blood served as the control.Fifty consecutive symptomatic pregnant women were recruited. Thick films of bothvenous and intradermal blood were examined. Questionnaires were used to determine patients' preference forthe two techniques. Tests of statistical significance were done with Fisher exact and Yates correlationcoefficient at 95% confidence interval. Sensitivity, specificity and accuracy rates were used to assess thevalidity of intradermal smear.Intradermal smear more frequently diagnosed malaria parasitaemia than peripheral venous blood(66% vs 56%). This was statistically significant (P value: 0.0065). The sensitivity of intradermal smear was85.7% while the positive predictive value was 77.4%. The accuracy rate was 76.7%. The technique ofintradermal blood collection was preferred by 28% of women.Intradermal smear is useful in malaria diagnosis in pregnancy and may be an additionalevaluation tool for persistent fever in pregnancy.: Intradermal smear, malaria in pregnancy, malaria diagnosis.Department of Obstetrics and Gynaecology, *Federal Medical Centre Katsina, Katsina State, **IrruaSpecialist Teaching Hospital, Edo State, ***University of Benin, Benin City, Edo State, ****ShellPetroleum Development Company, Warri, Delta State, *****Medical Microbiology, Irrua SpecialistTeaching Hospital, Edo State, Nigeria.(Accepted 5 January 2010)427Slide reporting:RESULTSThis Table shows the age Distribution ofParticipating Women.Thick films of both the venous and intradermal bloodwere examined under the light microscope forevidence of malaria parasite or pigment with oilimmersion technique at 10 × 100 magnification.Quantitative reporting of the slides was done per 100high power fields (HPF). The slides were reportednegative, if after viewing 100 fields, no parasites wereseen. However, for the positive slides, the number ofparasites/100 leukocytes was counted.Two laboratory scientists viewed the slides and thesewere classified as positive or negative. By theallocated study numbers on the slides, they wereblinded such that they did not know which wasintradermal or peripheral smear. Neither did theyknow which smear was from which patient. Theaverage of the two independent reports was used forthe study.Intradermal smear more frequently diagnosed malariaparasitaemia than peripheral blood (66% vs 56%).The ability of intradermal smear to diagnose malariain pregnancy was statistically significant (P value:0.0065). Thirty nine (78%) symptomatic womenpresented with complaints of fever although only 46%of them had a temperature of 37.2 C and above atpresentation. Other presenting symptoms includedheadaches, chills and body aches. The age distributionof study population is shown in table 1. As in table 2,nulliparous women constituted the majority (32%) ofthe women. Most of the women (54%) were in thethird trimester of pregnancy.Intradermal blood smear had a sensitivity of 85.7%.The specificity, however, was 56.3%. Table 3 showsthe comparison of IDS to BPF microscopy. Thepositive predictive value was 77.4% while thenegative predictive value was 69.2%. Intradermalsmear had an accuracy rate of 76.7%.The false positive and false negative rate ofintradermal blood smears in these women was 22.6%and 25% respectively. Twenty eight per cent of thewomen preferred the technique of collectingintradermal blood. 48% did not prefer the techniquewhile 14% were indifferent.The ability of intradermal smear to diagnose malariawas statistically significant (P value 0.0384; CI 95%)compared to peripheral venous blood film only innulliparous women.Table 1:0>Age Number Percentage (%)<20 1 220-24 11 2225-29 15 3030-34 9 1835-39 14 2840 0 0Total 50 100total parasite load than a conventional blood smear asintradermal smear remained positive for asignificantly longer period .Intradermal blood smear microscopy is simple, easyto perform and requires no special infrastructure forits performance and interpretation. Unlike peripheralblood film, it requires no training for venepuncture,so it would be useful in a primary health caresetting .All previous studies on intradermal smear were innon-pregnant subjects.Therefore we evaluated the usefulness of intradermalsmear in symptomatic antenatal women. Wedetermined the diagnostic accuracy of intradermalsmear as well as the degree of correlation withperipheral blood film microscopy in pregnancy. Thepatients' preference for the technique of intradermalsmear was also determined.This study was done at the antenatal clinic of IrruaSpecialist Teaching Hospital, Edo state, Nigeria. Itwas a comparative study and peripheral venousblood served as control. The study was approved bythe Medical Ethics Committee of the hospital andinformed consent was obtained from all women.Fifty consecutive symptomatic pregnant womenwere included in the study. All women had bothperipheral venous blood and intradermal bloodcollected and made into thick films which made up atotal of 100 slides. The sample size was calculated bythe statistical formula for comparative study basedon 3% prevalence of acute malaria in pregnancy. Theconfidence level was set at 95%.In order to determine the women's preference for thetechnique of intradermal blood collection, aquestionnaire was administered.Indices of test validity used were sensitivity,specificity, positive predictive value and accuracyrate.Tests of statistical significance were done withFisher exact and Yates correlation coefficient at 95%confidence interval.Urine microscopy and culture was done to excludeurinary tract infection. Respiratory examination wasalso done to exclude infection of the respiratorysystem. The other exclusion criterion was prolongedprelabour rupture of membranes >24hours(PPROM).The intradermal blood smear was made by makingseveral small intradermal pricks with a No 23 gaugeneedle within a small area (1× 1 cm) on the outeraspect of the upper arm. The area was gentlysqueezed and the blood made into a thick film on theslide. The slides were allocated numbers andthereafter stained with Giemsa stain.12131314MATERIALSAND METHODSExclusion criteriaProcedure for intradermal smearNigerian Journal of Clinical Practice Dec. 2010, Vol.13(4) Study of Intradermal Smear Okusanya et al 428Intradermal smearPositive NegativePeripheral venousbloodPositive 24 4Negative 10 12Table 2:>Table 3:P- value 0.0065; CI 95%The desire for a total eradication of malariaparasitaemia in pregnancy in order to avoidattendant consequences on the mother and her fetushas led to the evaluation of different diagnostictechniques for malaria detection in pregnancy.Peripheral blood film microscopy is the goldstandard for malaria parasite detection because of thevarious limitations of other forms of diagnosis,hence, there arises a need to optimize microscopy forthe diagnosis of malaria parasitaemia in pregnancy.There are no previous published studies onintradermal smear involving pregnant womendespite their susceptibility to malaria. Intradermalsmear represents a sequestered biomass of malariaparasites and demonstrates more frequent and ahigher parasite load than peripheral venous blood .These characteristics are similar to those of placentaparasitaemia.In this study, intradermal smear more frequentlydiagnosed malaria parasitaemia compared toperipheral venous blood (66% vs 56%).This wasstatistically significant (Pvalue: 0.0065).Participants in this study were mainly nullipara(32%) and primipara (20%) with most attacks ofacute malaria (54%) occurring in the third trimesterof pregnancy. This conforms to an earlier report thatmalaria in pregnancy is more common in the lasttrimester of pregnancy than the first . The womenpresented mainly with fever, headaches, chills andbody aches. Although 39 women complained offever at presentation, fever (Temp 37.2 C) could beobjectively demonstrated in only 46% of them, asmost immune pregnant women present with mildfebrile episodes .Parity of Women in the Study.Comparison of Intradermal Smear withPeripheral Blood Film.DISCUSSION913215o2Parity Number Percentage (%)0 16 321 11 222 10 203 6 124 4 85 3 6Total 50 100The sensitivity of intradermal smear depends on thelevel of parasitaemia and symptomatic women aremore likely to have parasitaemia. The ability ofintradermal smear to detect malaria parasitaemiawhen it was actually present was 85.7%. The importof this is intradermal smear for malaria parasite willtest negative in 14.3% of symptomatic pregnantwomen with malaria when the converse was the case.The reliability of the test, the positive predictivevalue, was 77.4%. This is a measure of theprobability of intradermal smear to detect malariaparasitaemia in the presence of malaria parasites.That is, it will correctly detect malaria parasitaemiain greater than seven (7) out of ten (10) cases. Thisstudy indicates that intradermal smear is useful in thesymptomatic pregnant women.Nigeria has a dearth of trained personnel to performvenepuncture at rural communities due to itstechnically demanding requirements, hence,intradermal smear microscopy could be useful inthese settings. It is simple, easy to perform andrequires no special infrastructure . It also requiresless training. Once the dermal blood is collected,however, the technique of staining is essentially thesame as that of venous blood and the cost is same.This is particularly important in low resourcesettings as ours. Intradermal smear may also beuseful in obese women in whom venepuncture couldbe very difficult.Moreover, in settings with relative unrestrictedaccess to antimalaria drugs as ours, intradermalsmear may be an additional investigation for malariaworkup as it demonstrated a persistence ofparasitaemia when venous blood was negative . Thisis particularly important in pregnancy, especially, aspregnant women with persistent fever may beinappropriately treated for Typhoid fever.The preference for the collection technique ofintradermal blood by 28% of the women was due tothe resentment of multiple skin pricks by majority ofwomen.In this study we did not evaluate speciesidentification. Previous works demonstrated more ofP. falciparum in intradermal smear than otherspecies . This is not only because is themost widely distributed and most common speciesin endemic areas of Africa , but also because matureforms of P. falciparum sequestrate in tissues .The findings from this study suggest that intradermalsmear is useful in the evaluation of women withsymptoms suggestive of malaria in pregnancy.Intradermal smear may find great usefulness inprimary health care and rural settings where there arefew trained personnel to perform venepuncture.Even in urban areas, it may be a good alternative todifficult venepuncture in obese women and thosewith persistent fever following treatment.13131312816P. falciparumNigerian Journal of Clinical Practice Dec. 2010, Vol.13(4) Study of Intradermal Smear Okusanya et al 4298. Harrison KA.9.10. VandeJagt TA, Ikeh EI, Ujah IO, BelmonteJ, Glew RH, Vandejagt DJ.11. Odhiambo RA, Odulaja A.12. Day NPJ, Diep PT, Ly Pt, Dinh XS, PhamPL, Ly VC, et al.13. Singh H, Sen R, Singh S, Siwach SB, Jagdish,Singh RM.14. Araoye MO.15. Opare-Addo HA, Odoi AT.16. Lucas AO, Gilles HM.Malaria in Pregnancy. Maternitycare in developing countries. RCOG Press2000:109-111.World Health Organization Regional office forAfrica. A strategic framework for malariaprevention and control during pregnancy intheAfrican region.2004.Afr/mal/04/01.Comparison ofthe OptiMAL rapid test and microscopy fordetection of malaria in pregnant women inNigeria. Trop Med Int Health 2005:10(1):39-41.New enzymaticassay, parasite lactate dehydrogenase, indiagnosis of malaria in Kenya. East Afri Med J2005:82(3):111-117.Clearance kinetics ofparasites and pigment containing leukocytes insevere malaria. Blood 1996;88: 2694-7000.Utility of intradermal smear in thed i a g n o s i s o f m a l a r i a . Tr o p D o c t2003;33(2):108- 110.Subject selection in Researchmethodology with statistics for health andsocial sciences Nathadex Publishers2004:115- 129.Malaria inpregnancy. In Comprehensive Obstetrics in thetropics ed E.Y Kwawukume, E. E. Emuveyan.Asante & Hittscher Printing Press Ltd2002:250-260.Arthropod-borneinfections. Short textbook for public healthmedicine for the tropics. 4 Ed. PublisherEdward Arnold 2003: 175- 233..thIntradermal smear is a useful technique for detectingmalaria parasitaemia in symptomatic pregnantwomen. It may also be useful as an additionalevaluation tool in pregnant women with persistentfever. We therefore recommend its introduction inthe evaluation of pregnant women with malariasymptoms due to its simple, easy technique and highsensitivity. Since previous studies on intradermalsmear were in non-pregnant women, there is a needfor more research on its usefulness in pregnancy. Itsrole in the detection of malaria parasitaemia inasymptomatic pregnant women needs to beevaluated.World Health Organization. Management ofsevere Malaria A practical Handbook 2000. 2edn. Geneva.Malaria during pregnancy.Contemporary Obstetrics and Gynaecology fordeveloping counties. Ed. Okonofua F andOdunsi K. Women's Health and ActionResearch Centre. 2003:502- 513.Anaemia, Malaria and sickle celldisease. Clinics in obstetrics and GynaecologyW.B Saunders company Ltd 1982; 9(3): 445-77.Prevalence ofmalaria parasitaemia in pregnancy in Nigerianwomen. J of Obstet and Gynaecol 1996; 16(5):8.Impact of asymptomatic maternal malariaparasitaemia at parturition on perinataloutcome. J Obstet Gynaecol 2002; 22(1):25-28.Does malariaduring pregnancy affect the newborn? J PakmedAssoc 2005; 55(12):543-546.Theeffect of malaria infection on maternal-fetaloutcome in Ecuador. J Matern Fetal NeonatalMed 2005; 18(2):101-105.REFERENCES1.2. Sowunmi A.3. Harrison KA.4. Okonofua FE, Abejide OR.5. Sule-Odu AO, Ogunledun A, Olatunji AO.6. Yakoob MY, Zakaria A,Waqar SN, Zafar S,Wahla AS, Zaidi SK et al.7. Espinoza E, Hidalgo L, Chedraui P.ndNigerian Journal of Clinical Practice Dec. 2010, Vol.13(4) Study of Intradermal Smear Okusanya et al 430

Comparative study of intradermal smear microscopy in the diagnosis of malaria in symptomatic pregnant women

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Comparative study of intradermal smear microscopy in the diagnosis of malaria in symptomatic pregnant women

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