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DIPHTHERIA Dr. RAJALEKSHMY.P.RDEPT: OF SWASTHAVRITTAAMRITA SCHOOL OF AYURVEDA

INTRODUCTION

Acute infectious disease caused by toxigenic strains of Coryne bacterium diphtheriae.3 major clinical types-anterior nasal, faucial, laryngealSkin, conjunctiva, vulva and other parts may be affected.Bacilli multiply locally in throat and produce powerful exotoxin.

HISTORYTook its name from greek word diphthera meaning leather.

Named in 1826 by French physician Pierre Bretonneau.

In the past, disease was called as general disease or killer disease because there was no treatment and was the cause of high mortality in children.

It was said that the disease killed as many as 80% of the children below 10 yrs.

PROBLEM STATEMENT

WORLDDeveloped countries

rare disease due to routine child vaccinationDeveloping countries

endemic due to lack of adequate widespread immunizationReported cases in 2010- 4187Epidemics are largely due to decreasing immunization coverage among infants and children, waning immunity to diphtheria in adults, movements of large groups of populations in the last few years and irregular supply of vaccines.

True no of cases are not known due to incomplete reporting.5

INDIAEndemic diseaseDeclining trend of diphtheria due to increasing coverage of child population by immunization .

Reported cases 1987- 12952 2011- 4286 112 deaths showing a case fatality rate of about 2.61

AGENT Agent Corynebacterium diphtheria

Gram positive motile organismNo invasive power but produce powerful exotoxin after multiplication locally in the throat responsible for:

Formation of false membrane over tonsils, pharynx or larynx, with well defined edges and membrane cannot be wiped away.Marked congestion, edema, local tissue destructionEnlargement of lymph nodesToxaemic signs and symptoms

4 types -Gravis Mitis Belfanti Intermedius

Sensitive to penicillin and readily killed by heat and chemical agentsAffects heart- myocarditis nerves- paralysis

Gravis more severe than mitis infection

SOURCE OF INFECTIONCases- ranges from sub clinical to clinical mild or silent infections may exhibit not more than a mere running nose or sore throat Carriers- common source of infection may be temperory or chronic;nasal or throat carriers

Nasal- dangerous( frequent shedding into environment)Temperory- lasts for 1 monthChronic- last for 1 year until the patient is treated

INFECTIVE MATERIAL

Naso-pharyngeal secretions Discharge from skin lesions Contaminated fomites Infected dusts

PERIOD OF INFECTIVITY

14 28 days from the onset of disease but carriers may remain infective for much longer periods.

A case or carrier may be considered non-communicable when atleast 2 cultures obtained from nose or throat, 24 hours apart are negative for diphtheria bacilli.

AGE

Children upto 1-5 yrsHOST FACTORSSEX

bothIMMUNITY

Infants borne of immune mothers are immune for first few weeks or months of life.

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ENVIRONMENTAL FACTORS

Cases occur in all seasons.Winter- favourableKolkata- highest incidence in augustMumbai- winter monthsDelhi- august or october

MODE OF TRANSMISSION

Droplet infectionsCan also be transmitted directly to susceptible persons from infected cutaneous lesions.Transmission by objects contaminated by naso-pharyngeal secretions of patients is also possible.

PORTAL OF ENTRYRespiratory route- respiratory tract

Non-respiratory route- Portal of entry may be skin where cuts, ulcers and wounds not properly attended to or through umbilicus of new born. Site of implantation may be eyes, genitalia or middle ear.

INCUBATION PERIOD

2- 6 days, ocassionally longer.

CLINICAL FEATURESRespiratory tract forms of diphtheria-

pharyngo-tonsillar laryngo tracheal nasal combinations

Pharyngo-tonsillar diphtheria

Sore throatDifficulty in swallowingLow grade fever at presentationPresence of pseudo membrane over tonsilsOedema in sub mandibular regionBull necked appearance

Throat examination- mild erythema, localized exudate, pseudo membrane. membrane may be localized or patch of post pharynx or tonsil,or may cover entire tonsil or spread to cover soft and hard palates and post portions of pharynx.early stage-white pseudo membrane wipe off easily.membrane may extend to become thick, bluewhite to grey black and adherent.attempts to remove membrane results in bleeding. An area of mucosal erythema surrounds the membrane. 19

Laryngo-tracheal diphtheria

Preceeded by pharyngo tonsillar diphtheriaFever, hoarseness and croupy coughDyspnoea

parenchymatous degeneration necrosis in heart muscles, liver, kidneys and adrenals vision difficulties, speech, swallowing or movements of arms or legsparalysis of soft palate, eye muscle or extremitiesToxin damage

Diphtheria bacilli within membrane produces toxin damage.20

Nasal diphtheria

Mildest formLocalized in septum or turbinates of one side of noseConjunctiva and genitals also sources of infectionMembrane extends to pharynx.

Cutaneous diphtheria

Common in tropical areasSecondary infection of previous infection or skin abrasionPresenting lesion-an ulcer surrounded by erythema and covered with membrane.

SCHICKS TESTIntra dermal test

Tests presence of antitoxin(immunity status) and state of hypersensitivity to diphtheria toxin.

Inject 0.2ml of Schick test toxin intradermally into skin of forearm, while into opposite arm- control (Schick toxin inactivated by heat) is injected.

Negative reactionsif the person is immune, no reaction of any kind.

In test arm, a circumscribed red flush of 10-50mm diameter appears within 24-36 hours reaching maximum development by 4th 7th day.This slowly fades into a brown patch and skin desquamates.Control arm shows no change.The person is susceptible to diphtheria.

Positive reaction

A red flush develops equally on both arms, much less circumscribed than true +ve reactions.Fades by 4th day.allergic reaction found in certain individualsSchick negative

Control arm shows pseudo positive reaction and test arm shows positive reaction.The person is susceptible to diphtheria.Pseudo-positive reactionsCombined reactions

CONTROL OF DIPHTHERIA

CASES & CARRIERS Early detection

Start active search immediately from family and school contacts.Carriers can be detected by culture methods. (swabs taken from nose and throat)

Isolation

all cases, suspected cases and carriers should be isolated, preferably in a hospital for atleast 14 days or until proved free of infection.

2 consecutive throat swabs taken 24 hours apart should be negative before terminating isolation.

Treatment-

Cases

Preliminary test dose of 0.2 ml subcutaneously to detect sensitization to horse serum.Followed by dip: antitoxin IM or IV in doses ranging from 20,000-40,000 units or more depending on severity of cases.Mild early pharyngeal or laryngeal: 20,000-40,000 unitsModerate naso pharyngeal: 40,000-60,000 unitsSevere, extensive or late disease: 80,000-100,000 units.Addition to antitoxin, penicillin or erythromycin for 5-6 days to clear throat.

Carriers

Should be treated in 10 days course of oral erythromycin

More than bacteria, the exotoxin is responsible for diphtheria. So should receive antitoxin without delay.29

CONTACTSShould be throat swabbed and immunity should be determined.Where primary immunization was received within the previous 2 years- no further action needed.Where primary course or booster dose of diphtheria toxoid was received more than 2 years before, only a booster dose of dip: toxoid need be given.Non-immunized close contacts should receive prophylatic penicilin or erythromycin.They should be given 1000-2000 units of antitoxin and actively immunized against diphtheria.

Different situations pose diferent options:30

COMMUNITY

Active immunization with diphtheria toxoid of all infants as early in life as possible with subsequent booster dose every 10 years thereafter.Immunization rate must be maintained at high level.

DIPHTHERIA IMMUNIZATION

Combined vaccines

DPTDTP(w)DTP(a)DT(d-tetanus toxoid)dT(diphtheria-tetanus, adult type)

single vaccines

FT(formal toxoid)APT(alum-precipitated toxoid)PTAP(purified toxoid- aluminium precipitate)PTAH(p:t:a: hydroxide) TAF(toxoid-anti toxin - flocculus)

Antisera

Diphtheria antitoxin

DPT VACCINEFor immunization of infants.Pertussis component enhances diphtheria toxoid.Types- plain and adsorbedAdsorption-carried out on a mineral carrier like aluminium phosphate or hydroxide.

STORAGE should not be frozenStored in refrigerator at 2-8 degree celsiusWill loose potency if kept at room temperature for a long time.

Optimum age-

Global Advisory Group of EPI recommended that DPT an be safely administered as early as 6 weeks after birth.

Doses-

3 doses of DPT each is 0.5ml.

Mode of admn-

All vaccines containing mineral carriers should be injected intramuscular.DPT given in upper and outer quadrants of gluteal region.

Extended programme on immunization35

Immunization schedule-

6 weeks10weeks14 weeks16-18 months (booster dose)5 years (DT)

Reactions-

Fever and mild local reactions2-6% develop fever of 39 degree or higher.5-10% experience swelling and induration.Neurological- encephalitis, prolonged convulsions, infantile spasms, Reyes syndrome.

Contra indications-

Seriously ill children or who need hospitalization are not vaccinated.Should not be repeated if a severe reaction occurred after a previous dose.In case of DPT, subsequent DT immunization.

Severe reactions- collapse or shock, persistent screaming episodes, temp above 40, convulsions, other neurological symptoms and anaphylactic reactions37

For children over the age of 5 years who have not received DPT- 2 doses of DT vaccine, 4 weeks apart, with a booster dose 6 months to 1 year later.Those children who received primary course of DPT earlier, should receive DT as booster at 5-6 years.For immunizing children over 12 years of age and adults, preparation dT (adult type diphtheria tetanus vaccine).Contains no more than 2 Lf diphtheria toxoid per dose.Admn:- 2 doses at interval of 4-6 weeks, followed by booster 6-12 months after second dose.

SINGLE VACCINESLess frequently used.Good immunizing agents.APT- hardly used; prone to give rise to severe infections.Each dose of these antigens generally contain 25 loeffler(lf) units of DT.

ANTI-SERAmain stay of passive prophylaxis and also for treatment in diphtheria. diphtheria antitoxin prepared in horse serum.