Corynebacterium Diphtheria: Clinical manifestation, Complications, Diagnosis and Treatment

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 tests:

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
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