Diphtheria
• Is an acute infectious disease of the childhood
characterized 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
Cont ..
Source : - secretions and discharge from an infected
person or carrier
– Human are chief reservoirs
Mode of transmission : – Contact or through droplets of secretion
Portal of entry :
– Respiratory tract
– May enter through the conjuntiva or skin
wound
Risk factors
1. Poor nutrition.
2. Outbreak in the community.
3. Crowded or unsanitary living conditions.
4. Low vaccine coverage among infants and
children.
5. Lack of mass immunization programmes
amongst children and adults at high risk.
6. Insufficient information for the general public on
dangers of the disease and the benefits of
immunization.
7. Lack of vaccines in many areas.
Pathogenesis
• Entry ------ the bacilli multiply locally in the throat and
elaborate a powerful exotoxin ----- produce local and
systemic symptoms.
Local lesions :
• Exotoxin causes necrosis of the epithelial cells and
liberates serous and fibrinous material which forms a
grayish white pseudomembrane
• The membrane bleeds on being dislodged
• Surrounding tissue is inflamed and edematous
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
Clinical features
• Incubation period : 2 – 5 days
Constitutional symptoms:
• Onset : acute with fever ( 39 C ) , malaise ,
headache and loss of appetite
• Child looks very sick and toxic
• Delirium
• Circulatory collapse ( myocarditis )
Local manifestation
Depend on the site of
lesion:
Nasal diphtheria :
• Unilateral or bilateral
serosanguineous ( blood and
serous fluid ) discharge from
the nose
• Excoriation of upper lip
• Toxemia is minimal
Faucial diphtheria :
• Redness and swelling over
fauces
• Exudates on the tonsils
coalesces to form grayish
white pseudo membrane
• Regional lymph nodes are
inflamed
• Sore throat and
• dysphagia
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.
Cont …
Laryngotracheal diphtheria :
– Membrane over the larynx results in
brassy ( hardness ) cough and
hoarse voice
– Respiration ------- noisy
– Suprasternal and subcostal
recession
– Restlessness
– Increasing respiratory effort
– Use of accessory muscles
Unusual sites :
• Conjunctiva and
skin
In the skin :
• Ulcers ( tender )
Diagnosis
• clinical history , examination and identification of
diphtheria bacilli from the site of lesion.
• Culture
• Albert`s staining
• Fluorescent antibody technique
Schick Test
–Schick test: It is an intradermal test,
the test is carried out by injecting
intradermally into the skin of
forearm 0.2 ml of diphtheria toxin,
while into the opposite arm is
injected as a control, the same
amount of toxin which has been
inactivated by heat.
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 in
diameter generally appears within 24-36 hours reaching
its maximum development by 4-7 days, the control arm
shows 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 certain
individuals
• Combined reaction: the control arm shows pseudo
positive reaction and the test arm is true +ve reaction,
susceptible and need vaccination
Differential diagnosis
Nasal diphtheria :
• Foreign body in nose ,
• Rhinorrhea
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•
•
•
•
Laryngeal diphtheria :
Croup
Acute epiglottitis
Laryngotracheobronchitis
Peritonsillar abscess
Retropharyngeal abscess
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 besides
oral mucosal lesions
Treatment
Principles :
• Neutralization of free circulating toxin by
administration of antitoxin
• Antibiotic to eradicate bacteria
• Supportive and symptomatic therapy
• Management of complication
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
Antibiotics
Penicillin :
• Procaine penicilline ( 3 – 6 lac units IM at 12
hourly intervals till the patient is able to swallow )
• Oral penicillin ( 125 – 250 mg qid )
• Erythromycin ( 25 – 30 mg / kg / day ) for 14
days
• Three negative cultures at 24 hours intervals
should be obtained before the patient is
declared free of the organism
Supportive and symptomatic therapy
• Bed rest for 2 – 3 weeks ( to reduce cardiac
complications )
• Antipyretics and sedative ( if required )
• Monitor rate and rhythm of the heart
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 )
Complications
Myocarditis :
• Occurs towards the end of the first or beginning
of second week
• Abdominal pain , vomiting , dyspnea ,
tachycardia
Neurological complications : ( Traid )
– Palatal paralysis ( 2 weeks )
– General polyneuritis ( 3 – 6 weeks )
– Loss of accommodation ( 3 weeks )
Renal complications :
• Oliguria and proteinuria indicate kidney
complications
Prevention
Vaccination: Immunisation with diphtheria toxoid,
combined with tetanus and pertussis toxoid (DTP
vaccine), 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 to
be protected for a further 10 years (16 – 18
years).
Prognosis
• Death may occur due to : – Respiratory obstruction
– Myocarditis
– Respiratory paralysis