Corynebacterium Diphtheria: Clinical manifestation, Complications, Diagnosis and Treatment

Susceptible to diphtheria [Ref. Park 19^th/e p 137]

Subseceptibles

Diptheria

Post exposure prophylaxis is used in HIV, HBV, Measles, Rabies, Tetanus, H.influenzae and Meningococcus.

Ans. is ‘d i.e., Schick test

Ans. is ‘b’ i.e., Elek’s Gel is a precipitation test 

.  Elek’s is a precipitation test. It is an in vitro test for toxigenicity of the diphtheria bacillus.

.   Selective medium for C. diphtheriae is tellurite blood agar (eg. Mc Leod’s and Hoyle’s media or cystine – tellurite agar – Tinsdale medium).

.  All strains of C. diphtheriae show metachromatic granules on staining.

.  C. diphtheriae is gram (+) ^ye, nonmotile and non-capsulated.

Based on colonial morphology on tellurite agar and other properties, Mc Leod classified diphtheria bacilli into three bio types – gravis, intermedius and mitis. Gravis causing most serious and mitis the mildest variety of diphtheria.

Ans. is ‘b’ i.e.,Incubation period 2-5 days

.  Diptheria is caused by Gram positive bacilli, Corynebacterium diphtheriae

.   Incubation period of most common form of diphtheria ( faucial/ tonsiliopharyngeal diphtheria) is 2-5 days.

. For chemoprophylaxis erythromycin or penicillin are used.

” Previously immunized asymptomatic household contact should receive booster dose of diphtheria toxoid. Those not fully immunized but asymptomatic contacts should receive immunization for their age”.—0.P. Ghai 7th/221 “Lifelong immunity is usually, but not always, acquired after disease or inapparent infection”—health.vic.gov.au> IDAES home > blue book

. So, child recovered from illness is already is immune. No active immunization is required.

Ans. is ‘c’ i.e., Isolated ocular palsies 

Complications

o Obstruction of the respiratory tract by pseudomembrane

o Myocarditis

• Polyneuropathy
• Post diphtheritic paralysis q Occurs in the 3rd or 4th week

o Palatine and pupillary paralysis is characteristic

Spontaneous recovery is the rule.

• Pneumonia

o Other less common complications are renal failure, encephalitis, cerebral infarction, pulmonary embolism and bacteremia or endocarditis.

Ans. is ‘b’ i.e., 2-5 years 

Diphtheria

o Diphtheria is an acute infectious disease caused by toxigenic strains of corynebacterium diphtheriae.

o Source of infection –> cases or carriers; carriers are common sources of infection, their ratio is estimated to be 95 carriers for 5 clinical cases.

o Infective period              –> 14 – 28 days from the onset of disease.

o Age group                                     —> 1 to 5 years

o Sex                                    –> Both sexes

o Incubation period            –> 2 – 6 days

Ans. is ‘b’ i.e., Positive test means that person is immune to diphtheria 

A i.e. Gonococcus; C i.e. Diptheria 

The only organisms known to be able to invade normal corneal epithelium are N. gonorrhoea & Cornybacterium diptheria Q