diphtheria (1)

7/28/2019 Diphtheria (1)

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Diphtheria

Is an acute infectious disease of the childhoodcharacterized by local inflammation of the

epithelial surface , formation of a membrane ,

and severe toxemia

Epidemiology : -

Age groups : Pre school age children

Occurs in the autumn and winter months.

Caused by ---- Gram positive bacilli,

Corynebacterium diphtheria


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Cont ..

Source : -

- secretions and discharge from an infectedperson or carrier

Human are chief reservoirsMode of transmission : -

Contact or through droplets of secretion

Portal of entry : Respiratory tract

May enter through the conjuntiva or skinwound


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Risk factors1. Poor nutrition.

2. Outbreak in the community.

3. Crowded or unsanitary living conditions.

4. Low vaccine coverage among infants andchildren.

5. Lack of mass immunization programmesamongst children and adults at high risk.

6. Insufficient information for the general public ondangers of the disease and the benefits ofimmunization.

7. Lack of vaccines in many areas.


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Pathogenesis

Entry ------ the bacilli multiply locally in the throat andelaborate a powerful exotoxin ----- produce local andsystemic symptoms.

Local lesions : Exotoxin causes necrosis of the epithelial cells and

liberates serous and fibrinous material which forms agrayish white pseudomembrane

The membrane bleeds on being dislodged

Surrounding tissue is inflamed and edematous


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Cont

Systemic lesions : Exotoxin affects the heart , kidney and CNS

Heart : Myocardial fibers are degenerated and the

heart is dilated

Conduction disturbance

CNS : polyneuritis

Kidney : renal tubular necrosis


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Clinical features

Incubation period : 2

5 daysConstitutional symptoms:

Onset : acute with fever ( 39 C ) , malaise ,

headache and loss of appetite

Child looks very sick and toxic

Delirium

Circulatory collapse ( myocarditis )


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Local manifestationDepend on the site of

lesion:Nasal diphtheria :

Unilateral or bilateralserosanguineous ( blood andserous fluid ) discharge from

the nose Excoriation of upper lip

Toxemia is minimal

Faucial diphtheria :

Redness and swelling overfauces

Exudates on the tonsilscoalesces to form grayishwhite pseudo membrane

Regional lymph nodes areinflamed

Sore throat and

dysphagia


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Fauces ( throat )

Fauces : - two pillars of mucous membrane.

Anterior : known as the palatoglossal arch and

Posterior : the palatopharyngeal arch

Between these two arches is the palatine tonsil.


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Cont Laryngotracheal diphtheria :

Membrane over the larynx results in

brassy ( hardness ) cough and

hoarse voice

Respiration ------- noisy

Suprasternal and subcostalrecession

Restlessness

Increasing respiratory effort

Use of accessory muscles

Unusual sites :

Conjunctiva andskin

In the skin :

Ulcers ( tender )


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Diagnosis

clinical history , examination and identification of

diphtheria bacilli from the site of lesion.

Culture

Albert`s staining

Fluorescent antibody technique


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Schick Test

Schick test: It is an intradermal test,

the test is carried out by injecting

intradermally into the skin offorearm 0.2 ml of diphtheria toxin,

while into the opposite arm is

injected as a control, the sameamount of toxin which has been

inactivated by heat.


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Interpretation Negative reaction: If a person had immunity to diphtheria,

no reaction will be observed on either arm.

Positive reaction: An area of in duration 10-15 mm indiameter generally appears within 24-36 hours reachingits maximum development by 4-7 days, the control armshows no change. The person is susceptible to diphtheria.

False positive reaction: A red flush develops in both arms,the reaction fades very quickly, and disappears by 4th day.This is an allergic type of reaction found in certainindividuals

Combined reaction: the control arm shows pseudopositive reaction and the test arm is true +ve reaction,

susceptible and need vaccination


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Differential diagnosisNasal diphtheria :

Foreign body in nose , Rhinorrhea

Laryngeal diphtheria :

Croup

Acute epiglottitis

Laryngotracheobronchitis Peritonsillar abscess

Retropharyngeal abscess


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Cont .Faucial diphtheria :

Acute streptococcal membranous tonsillitis (

high grade fever , child less toxic )

Viral membranous tonsillitis :

high grade fever ,

WBC : normal or low , Antibiotic : no effects

Herpetic tonsillitis ( Gingivitis and stomatitis )

Infectious mononeucleosis :

Generalised rash and lymphadenopathy besidesoral mucosal lesions


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Treatment

Principles :

Neutralization of free circulating toxin byadministration of antitoxin

Antibiotic to eradicate bacteria

Supportive and symptomatic therapy

Management of complication


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Antitoxin

Diphtheria antitoxin :

Pharyngeal or laryngeal diphtheria of 48 hours

duration : 20,000 to 40,000 units.

Nasopharyngeal lesions : 40,000 60,000 units

Extensive disease of 3 or more days duration or

patient with swelling of neck : 80,000 120,000

units Antitoxin may be repeated if the clinical

improvementis slower


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Antibiotics

Penicillin :

Procaine penicilline ( 3 6 lac units IM at 12hourly intervals till the patient is able to swallow )

Oral penicillin ( 125 250 mg qid )

Erythromycin ( 25 30 mg / kg / day ) for 14days

Three negative cultures at 24 hours intervalsshould be obtained before the patient isdeclared free of the organism


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Supportive and symptomatic therapy

Bed rest for 2 3 weeks ( to reduce cardiaccomplications )

Antipyretics and sedative ( if required )

Monitor rate and rhythm of the heart


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Management of complication

Respiratory obstruction :

Humidified oxygen

Tracheostomy

Myocarditis :

Fluids and salt restriction

Sedation and oxygen supply

Diuretics and digoxin

Neurological complications :

Palatal paralysis ( NG feeding )

Generalised weakness ( as polio )


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Complications

Myocarditis : Occurs towards the end of the first or beginning

of second week

Abdominal pain , vomiting , dyspnea ,

tachycardiaNeurological complications : ( Traid ) Palatal paralysis ( 2 weeks )

General polyneuritis ( 3 6 weeks )

Loss of accommodation ( 3 weeks )

Renal complications :

Oliguria and proteinuria indicate kidney

complications


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Prevention

Vaccination: Immunisation with diphtheria toxoid,combined with tetanus and pertussis toxoid (DTPvaccine), should be given to all children at two,three and four months of age. Booster doses are

given between the ages of 3 and 5 .

The child is given a further booster vaccine

before leaving school and is then considered tobe protected for a further 10 years (16 18years).


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Prognosis

Death may occur due to : -

Respiratory obstruction

Myocarditis

Respiratory paralysis

diphtheria (1)

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