Corynebacterium Diphtheria: Clinical manifestation, Complications, Diagnosis and Treatment
Introduction
- Most common in children of 2-5 years.
Incubation period
- 2-5days
Mode of transmission
- Droplet spread
Types
- Faucial(commonest )
- Laryngeal
- Nasal
- Conjunctival
- Otitic
- Vulvovaginal
- Cutaneous mainly around mouth and nose
Respiratory Diphtheria
- MC type Tonsillopharyngeal (Faucial)
- Symptoms
- Fever
- sore throat
- Weakness
- Malignant or hypertoxic or bull neck appearance
- Complications
- Mechanical complication
- Pseudomembrane may extend to the larynx
- Lead to laryngeal obstruction, asphyxia and death.
- Systemic effects
- Myocarditis:Cardiac damage permanent
- peripheral polyneuropathy of descending type.
- Risk
- Involvement larynx or tracheobronchial tree
- Children(because of small airway size).
- First muscle involve in paralysis – palatopharynges.
- Ciliary paralysis occur but not pupillary paralysis
- Most common ophthalmic effect of diphtheria is Isolated ocular palsies
- Blurred vision with preserved light reflex.
- Degenerative changes in adrenal, kidney and liver may occur.
- Cause of death
- circulatory failure.
Cutaneous Diphtheria
- Punched out ulcers
- Caused by non-toxigenic strains.
Invasive infection
- Rare
- Risk factors are
- preexisting cardiac abnormalities
- IV drug abusers
- alcoholic cirrhosi
Prevention
- Active immunization by Toxoid
- Immunization cannot prevent carrier stage.
- Active immunization –
- Combined DPT.
- Perfussis component in DPT increase potency of diphtheria toxoid.
- Toxoid of diphtheria shows Danysz phenomenon and Ehrlich phenomenon
- contact isolation is must.
DIAGNOSIS:
Culture:
- Respiratory diphtheria diagnosis clinical
- Cutaneous diphtheria requires lab confirmation.
The throat swabs are inoculated on the following culture media:
- Loefflers serum slope
- Tellurite blood agar
- Blood agar
Virulence tests:
- These tests demonstrate the production of exotoxin by bacteria isolated on culture.
Virulence testing may be done by:
- In vivo: Guinea pigs and rabbits- by subcutaneous or intracutaneous.
- In vitro: Eleks gel precipitation test ( test for toxigenicity)and tissue culture tests
- Schick test:
- Done to demonstrate circulating diptheria antitoxin.
- Skin test based on neutralization reaction
| CONTROL ARM | TEST ARM | INFERENCE |
| No Reaction | No Reaction | Immune |
| No Reaction | Positive
Red flush of 1-5 cms diameter, generally appears within 24-36 hr reaching its maximum develop- ment by 4-7 day. This fades slowly |
Susceptible to infection |
|
Red flush but less circumscribed than positive fades by 4th day |
Pseudo positive
Red flush equally in both arms less circumscribed |
Allergic type interpreted as Schick type |
| Pseudo positive reaction | Show positive reaction
Combined reaction |
Susceptible |
TREATMENT:
- Erythromycin (orally or by injection) for 14 days (40 mg/kg per day with a maximum of 2 g/d), or
- Procaine penicillin G given intramuscularly for 14 days (300,000 U/d for patients weighing10 kg).
- Patients with allergies to penicillin G or erythromycin can use rifampin or clindamycin.
- Diphtheria antitoxin is given intradermal
- Post exposure prophylaxis in health care professionals is not indicated in infections with diphtheria
Exam Important
Introduction
- Most common in children of 2-5 years.
Incubation period
- 2-5days
Mode of transmission
- Droplet spread
Types
- Faucial(commonest )
- Laryngeal
- Nasal
- Conjunctival
- Otitic
- Vulvovaginal
- Cutaneous mainly around mouth and nose
Respiratory Diphtheria
- MC type Tonsillopharyngeal (Faucial)
- Complications
- Mechanical complication
- Pseudomembrane may extend to the larynx
- Lead to laryngeal obstruction, asphyxia and death.
- Systemic effects
- Myocarditis
- Peripheral polyneuropathy of descending type.
- First muscle involve in paralysis – palatopharynges.
- Ciliary paralysis occur but not pupillary paralysis
- Most common ophthalmic effect of diphtheria is Isolated ocular palsies
Cutaneous Diphtheria
- Punched out ulcers
- Caused by non-toxigenic strains.
Invasive infection
- Rare
DIAGNOSIS:
Culture:
- Respiratory diphtheria diagnosis clinical
- Cutaneous diphtheria requires lab confirmation.
- The throat swabs are inoculated.
Virulence testing may be done by:
- In vivo: Guinea pigs and rabbits- by subcutaneous or intracutaneous.
- In vitro: Eleks gel precipitation test ( test for toxigenicity)and tissue culture tests
Schick test:
- Done to demonstrate circulating diptheria antitoxin.
- Skin test based on neutralization reaction
| CONTROL ARM | TEST ARM | INFERENCE |
| No Reaction | No Reaction | Immune |
| No Reaction | Positive
Red flush of 1-5 cms diameter, generally appears within 24-36 hr reaching its maximum develop- ment by 4-7 day. This fadesslowly |
Susceptible to infection |
|
Red flush but less circumscribed than positive fades by 4th day |
Pseudo positive
Red flush equally in both arms less circumscribed |
Allergic type
interpreted as Schick type |
| Pseudo positive reaction | Show positive reaction
Combined reaction |
Susceptible |
TREATMENT:
- Erythromycin DOC
- Procaine penicillin G .
- Patients with allergies to penicillin G or erythromycin can use rifampin or clindamycin.
- Diphtheria antitoxin is given intradermal
- Post exposure prophylaxis in health care professionals is not indicated in infections with diphtheria
