Diagnosing Rubella : Fallacies and Pitfalls

ME Yeolekar

Correspondence

Sir,Congenital rubella is a preventable disease, whichcould be controlled by immunization. Serologicalsurveys in India indicate that up to 45% of women ofchild-bearing age are susceptible to rubella andpotentially at risk of infection during pregnancy.1 Sinceprimary infection with rubella in the first four months ofpregnancy carries a major risk of foetal damage, correctand early diagnosis of rubella is of vital importance.

Clinically diagnosis of rubella could be missed dueto following reasons:

1.Rubella is a mild viral exanthematous infectiousdisease, which follows a typically benign clinicalcourse.

2.The infection may present atypically with minimumlymphadenopathy and an evanescent rash.

3.Typical rubelliform rashes may also be induced byother viruses like enteroviruses, chikungunya virus,Ross river virus and Parvo virus B19.

Diagnosis of Rubella could be confirmed by viralculture but the process is difficult and the facilities forculture are lacking in most of the laboratories. Hence,serodiagnosis is considered the most useful and reliablemethod for detection of infection. Acute rubella infectionis usually established by demonstration ofseroconversion in paired sera or by demonstration ofrubella-specific IgM antibodies in a single specimen. IgMantibodies usually attain their maximum concentrationwithin 10-14 days after the onset of illness but theduration of response is variable. In general, followingprimary infection, they persist for 6-12 weeks althoughsome patients may exhibit a more prolonged response,which may extend for as long as a year.

ELISA is a rapid and reliable method of measuringrubella specific IgM antibodies in the serum sample ofpatients with acute rubella infection. However, there areseveral pitfalls. All assays for specific IgM antibodiesoccasionally give false positive results. Lowconcentration may occur in infections like infectiousmononucleosis. Parvo virus B19 infection and CMVinfection and also if rheumatoid factor is present.2 Afurther problem is to distinguish primary rubella fromreinfection. Reinfection is diagnosed when an antibodyresponse is shown in someone who has previously hadnatural rubella or successful immunization. It has beenrecommended by a working party of the MedicalResearch Council’s subcommittee on Rubella Vaccinethat evidence of re-infection would be accepted if aperson with pre-existing rubella antibodies showed asignificant rise in antibody concentration or a rubellaspecific IgM response, or both. Distinction between primary infection and re-infection could also be doneon basis of avidity of specific IgG antibodies. Highavidity suggests recent re-infection. But avidity assayshave not yet been elucidated in routine use.3

Rubella specific IgM response during re-infection isusually lower and more transient than primary infection.Asymptomatic re-infection in early pregnancy is veryunlikely to be associated with foetal infection. However,if it is accompanied by significant viraemia, transmissionto foetus can cause significant damage.

In our study conducted on 380 females of reproductiveage, IgM antibodies were present in 26/380 (6.84%).However, further analysis of these females showed that21 of them were seronegative for IgG antibodiesindicating primary infection. Five of them had IgGantibodies along with IgM antibodies indicating re-infection in them. Correct diagnosis of primary rubellaor re-infection in patients without symptoms may thusbe difficult. Hence, we emphasize the fact that a properNational Immunization Policy should be formulated toimmunize adolescent females against rubella before theycontemplate pregnancy.

N Jindal, N Singla, A Aggarwal
Department of Microbiology, Govt. Medical College,Amritsar. Department of Microbiology, Govt. MedicalCollege and Hospital, Sector 32 Chandigarh.Received : 16.2.2005; Accepted : 22.8.2005

REFERENCES

1.Seth P, Manjunath N, Balaya S. Rubella infection : The IndianScene. Rev Inf Dis 1985;7:S64-67.

2.Morgan - Capner P. Diagnosing rubella. Br Med J1989;299:338-39.

3.Best JM, Banatvala JE, Morgan-Capner P, Miller E. Foetalinfection after maternal reinfection with rubella : Criteria fordefining reinfection. Br Med J 1989;299:773-5.


Unilateral Chorioretinitis : An InitialManifestation of Subacute SclerosingPanencephalitis

Sir,

SSPE is a devastating neurologic disorder associatedwith persistent measles virus infection of the nervoussystem with an invariably fatal outcome. A wide varietyof visual disorders have been associated with SSPEincluding papilledema, retinitis, chorioretinitis, opticnerve pallor, homonymous visual field deficits, andcortical blindness. Adult-onset patients are more likelythan children to present with purely ophthalmologiccomplaints rather than the classical personality changesas their first symptom of disease.1 We report aninteresting case of SSPE who developed acute onsetunilateral chorioretinitis as an initial manifestation preceding the neurological symptoms by three and ahalf years!

A 16-year-old Hindu male born of a non-consanguineous marriage, from a rural background wasnoted to have subtle forgetfulness and impairedconcentration in routine activities for past 6 months. Thiswas associated with progressively increasing recurrentjerky movements of the axial musculature and limbs,sometimes with falls, three episodes of generalizedseizures, and progressively decreasing scholasticperformance at school, impaired calculation,visuospatial abnormalities and recent memoryimpairment. About three and a half years prior to thishe had developed acute onset painless vision loss overright eye and within four hours only finger countingwas possible at one feet distance.

This was not associated with any constitutionalsymptoms, any systemic manifestations or any otherfocal neurological deficit at that time or in the past.Patient was not investigated for it and nor did he takeany specific treatment. Vision loss had improved for thepast 2-3 months and now he was able to count fingersfrom a 1 meter distance. Patient had a past history ofmeasles infection at the age of one and a half years. Theattendant could not recall details about vaccination.Family history was negative for any progressiveneurodegenerative disorder and or epilepsy.

General examination was normal. His MMSE was21/30. Detailed Higher mental function testing revealedmainly parieto-occipital dysfunction followed bytemporal and subtle frontal lobe dysfunction. Cranialnerve testing revealed RAPD right eye, diminishedvisual acuity right eye with finger counting possible at 3feet distance, temporal pallor of the disc with macularand perimacular pigmentation surrounded by anatrophic scar. Patient had a characteristic periodicpredominant axial myoclonus recurring after every 15seconds. Routine biochemical parameters were normal,HIV and VDRL were negative. CT scan of the brain wasnormal. EEG revealed characteristics periodic complexesconsistant with a diagnosis of SSPE. CSF revealed normalcell count end sugar with mildly raised proteins. Serumand CSF antimeasles IgG antibody titre was significantlyelevated. Based on the clinical symptomatology,characteristic periodic complexes, CSF picture, with abackground history of childhood measles infection adiagnosis of SSPE was made.

Although high (50%) of ocular involvement usuallyoccurs concurrently with the neurological features , yetvision loss as an early feature, preceding the appearanceof typical myoclonus and cognitive decline by monthsand even as long as eight years has been described!especially with increasing age of presentation.2,3 Ourpatient is also unusual that he had a three and a halfyear gap between the ocular and neurologicalmanifestations. Possibly the patient’s immunologic system was able to contain and abort a presumablemeasles viral retinitis in his right eye but failed in doingso three and a half years later years later leading toneurological manifestations.

Because of high percentage (50%) of ocularinvolvement in SSPE, which may antedate the othersymptoms by even years and no definitive treatmentavailable, any child or adult presenting withunexplained or atypical vision loss must be necessarilyenquired about childhood measles infection andvaccination otherwise a potentially devastating disordermay be missed!

R Pati, Archana Verma, P Kumar, LD ParhiDeepika Joshi, S Misra

Resident Doctor; Lecturer; Professor and Head,Department of Neurology, Institute of Medical Sciences,Banaras Hindu University, Varanasi – 221 005.Received : 15.6.2005; Revised : 8.8.2005; Accepted : 13.9.2005

REFERENCES

1.Singer C, Lang AE, Suchowersky O. Adult-Onset SubacuteSclerosing Panencephalitis: Case Reports and Review of theLiterature. Movement Disorders 1997;12:342-53.

2.Park DW, Boldt C, Massicotte SJ, et al. Subacute SclerosingPan encephalitis manifesting as viral retinitis: clinical andhistopathological findings. Am J Ophthalmology 1997; 123533-542.

3.Khadilkar, Satish V Patil, Shekhar G Kulkarni, Kedar S. Astudy of SSPE: early clinical features. J Pediatric Neurology2004;2:73-77.


Ocular Changes in Infectious Diseases

Sir,

Ophthalmoscopy is a very important bedside test bywhich a person can diagnose, give the differentialdiagnoses in undiagnosed patient and once diagnosedcan also give the prognosis in various infectious andnoninfectious diseases. Ophthalmoscopic changes arewell described in non-communicable diseases iehypertension, diabetes mellitus congenital/hereditarymetabolic disorders etc. but it is not so in cases ofinfectious diseases because of variability of incidence,prevalence/epidemics from place to place, emergence ofnewer infections and last but not least the infectiousdiseases are mainly the burden of third world countrieswhich are mostly resource poor.

Ocular/Ophthalmoscopic changes are well describedin some infections ie malaria, infective endocarditis,cysticercosis, HIV to name few of them. In the July 2005issue of JAPI (53;656-57) - the detailed report of five casesby Mehta is worth praise.1 We have earlier studied ocularchanges in more than 400 patients of plasmodiumfalciparum malaria in which all categories of patients ieuncomplicated and complicated/prenicious syndromecases were included.2 According to the available literaturefrom 1879 to 1996 there were varying results in differentstudies which could be due to geogrpahical factors,variable strains of the plasmodial species, varying definition of various indices of severity, smaller numberof patients population in the studies. so we conducted alarger prospective study and finally it was concludedthat ophthalmoscopic abnormalities per se are notassociated with mortality statistically except disc pallor(which could be due to fewer number of patients withdisc pallor) but there was a trend towards worseprognosis. It was also concluded that some fundusfindigns ie retinal hemorrhages in malaria endemic areasmay give a possible diagnosis of malaria if peripheralblood film is negative and otherwise there is strongsuspicion of malaria.2,3

Our findings were similar to the findings to Denguepatients described by Mehta with regards to morphologyand recovery point of view ie subconjunctivalhaemorrhage, retinal haemorrhage, Roth's spots butmaculopathy was not observed in our study.2,3 So theocular findings are probably reflection of underlyinganaemia, thrombocytopenia and bleeding tendency.

As there are frequent outbreaks of Dengue from timeto time in various parts of India so we agree with theauthor's comment that-an effort should be made to detectand document the findings in larger number of patientswhenever there is an opportunity. We would like to addfurther to the author's comment that the ocular lesionsbe studied in all verities of Dengue fever and not only inpatients of Dengue hemorrhagic fever as we did in ourstudy on malaria patients to become more wise.

Shubhakaran, Rekha Jakhar

Department of Neurology, MG Hospital. Department ofObs and Gynae, Dr. SN Medical College, Jodhpur - Rajasthan.Received : 23.8.2005; Accepted : 15.9.2005

REFERENCES

1.Mehta S. Ocular lesions in severe Dengue hemorhagic fever(DHF). J Assoc Physicians India 2005;53:656-57.

2.Kochar DK, Shubhakaran, Kumawat BL, et al.Ophthalmoscopic abnormalities in adults with falciparummalaria. Quart J Med 1998;1998:845-52.

3.Kochar DK, Shubhakaran, Kumuwat BL, Kochar SK.Prognostic significance of eye changes in cerebral malaria. JAssoc Physicians India 2000;48:473-77.

Reply From the Authors

Sir,

I am grateful for the interest and appreciation shown by Dr. Shubhakaran et al to my correspondence.1

1
The authors have made a significant contribution toliterature both by reporting the varied fundusfindings of a large cohort of patients of malaria2 andby excellent reviews.3 I agree with their conclusionthat fundoscopy may be of help in the diagnosis ofmalaria especially when the peripheral blood smearsmay be negative.
2
The subconjunctival and intraretinal hemorrhagesare likely due to an underlying thrombocytopeniathat is well reported in these patients. Themaculopathy is an infrequently reported findingwith only a few cases being reported worldwide.The exact etiopathogenesis is still unclear butpossibly represents direct tissue invasion. A largerseries would be needed to elucidate whether any ofthese findings are risk factors towards a worseoutcome.
3
All these patients were admitted, mostly in theintensive care units, and were thus examined by us.Mild or subclinical infections often seek no treatmentor are treated empirically as "pyrexia of unknownorigin (PUO)" and do not undergo fundoscopy. I agreethat these findings, if available would be aninteresting study.
4
Ophthalmoscopy remains an underutilized tool byphysicians and further studies will help establishthe role of fundoscopy in PUO.

Salil Mehta
Lilavati Hospital, Bandra, Mumbai 400 050.Received : 23.8.2005; Accepted : 15.9.2005

REFERENCES

1.Mehta S. Ocular lesions in severe dengue hemorrhagic fever(DHF). J Assoc Phys of India 2005;53:656-57.

2.Kochar DK, Saxena V, Singh N, Kochar SK, Kumar SV, DasA. Plasmodium vivax malaria. Emerg Infect Dis2005;11:132-4.

3.Kochar DK, Shubhakaran, Kumawat BL, Vyas SP. Prognosticsignificance of eye changes in cerebral malaria. J AssocPhysicians India 2000;48:473-7.

4.Kochar DK, Shubhakaran, Kumawat BL, Thanvi I, Joshi A,Vyas SP. Ophthalmoscopic abnormalities in adults withfalciparum malaria. QJM 1998;91:845-52.


Erratum

In the Editorial entitled “Whose life is it, anyway? The evolving face of Euthanasia” published in JAPI2005; 53:279-281, the 5th paragraph should read as “When the person who is killed has made and expresseda wish to be killed” it is termed as Voluntary Euthanasia.

- Editor