Diptheria Flashcards
Diphtheria is a bacterial URTI
T/F
T
Diphtheria
Aetiological Agent:
•________________
Corynebacterium diphtheriae
Diphtheria
Characteristics
• Gram __________
• Sporulating or Non-sporulating
• Encaspulated or Non-encapsulated
• Motile or Non-motile
•coccus or bacillus
positive
Non-sporulating
Non-encapsulated
Non-motile
Bacillus
Diphtheria
_______ are the only known reservoir
Humans
Diphtheria
Transmission:
• Spreads via _________ and _______
•____________ is important in transmission
air droplets and direct contact
Asymptomatic carriage
Diphtheria
Incubation period of _____-_____
2-5 days
Morphology of diphtheria
______ shaped
________ granules giving a _______ appearance
Club
Metachromatic
beaded
Morphology of diphtheria
______ lettering appearance, because the ____________ or at _______ to each other
Chinese
rods lie parallel
acute angles
Morphology:
On blood agar, the diphtheria colonies are (small or large?) and ____color with ______ edges
On tellurite blood agar, it produces _____________ colonies
Small; gray ; irregular
brown or black
__________ media for corynebacterium diphtheria
Loeffler’s serum
Biotypes of Corynebacterium Diphtheriae
List 4
Gravis
Intermedius
Mitis
Belfanti
Diphtheria Virulence factors
Diphtheria toxin
• Heat ______
• Has _________ Fragments
labile
A and B
Diphtheria Virulence factors
Diphtheria toxin
Fragment A: inhibits _______________
Fragment B: binds to ______ and ___________________________ via _______________
polypeptide chain elongation
receptors
allows the rest of the toxin (Fragment A) to enter the cell
receptor mediated endocytosis
Pathogenesis of Diptheria
Diphtheria toxin gets into Mucous membranes
Destroys _______ and causes _______ that leads to ______
_______+ _______+ _______+ _______ forms a __________ over the tonsils, pharynx and larynx
_______________ become enlarged.
membrane epithelium
inflammation; necrosis
Necrotic epithelium + Fibrin + red and white cells
grayish pseudomembrane
Regional lymph nodes
Pathogenesis
• Toxin can also cause distant damages, particularly to;
________
___________
_________
_________
____________
Heart muscle
Liver
Kidneys
Adrenal Glands
Nerves (demyelination)
• diphtheriae does not need to be toxigenic to establish localized infection but nontoxigenic strains do not yield the localized or systemic toxic effects.
Tf?
Clinical Features
————
Fever
Dyspnea (due to the _________)
_______
______itis
______________
Cutaneous infection causes _________
Sore throat
pseudomembrane
Suffocation
Card
Motor Neuropathy
indolent ulcers
Circulating diptheria toxin is potentially fatal
T/F
T
Clinical Features of diptheria
Fever : Low or High ? grade
Low
Diagnosis of Diptheria
Presumptive
Confirmation by observing ______ on Tellurite medium
______ shows toxic gene
_________
Brown colonies
PCR
Culture
Diagnosis of Diptheria
Culture
_________ plate, ______ serum agar or modified _______ are preferred.
______ agar or _____ agar may also be used
______ from nose, throat or other suspected lesions are used
Tellurite; Loffler’s
Tinsdale medium
Blood; Pai
Swabs
Diptheria test for Toxigenicity
_____ Test
PCR
ELISA
Immunographic strip assay
Elek
Therapy for Diphtheria
_________________ is given IV before waiting for diagnosis
Antimicrobials e.g Penicillin, erythromycin inhibits bacterial growth thereby _______________
Diphtheria Antitoxin (DAT)
arresting toxin production
Prevention of Diphtheria
•_________________
• Chemoprophylaxis for close contacts
Toxoid immunization (DPT)
Gram stain
Staining is (uniform or uneven?), ___________ appearance
Uneven
cross-banded
metachromatic or _______ granules
volutin
Sites of infection
Main - _______,_____,______
Others -_____,______
pharynx, larynx , nose
skin, genitals
Non toxigenic strains also cause diptheria,
T/F
F
Non toxigenic strains do not cause diptheria, but may cause other diseases e. g. endocarditis, septicaemia
__________ on attempting to remove the pseudomembrane
Bleeding
__________ enlarged to give the bull neck appearance
Cervical nodes
Cervical nodes enlarged to give the ______ appearance
bull neck
Clinical types - ______________
Most severe form, high mortality, sequelae
nasopharyngeal
Clinical types -nasopharyngeal
________
___________
Faucial
Laryngeal
Clinical types -nasopharyngeal
Faucial;affects _____,_____,_____,______
Difficulty in ________,
__________ lymph nodes
Laryngeal
secondary to ____________.
_______ obstruction ; Cervical nodes present
tonsils, uvula, soft palate, pharynx
swallowing; Enlarged neck
faucial diphtheria; respiratory
Clinical types
• Anterior nasal diphtheria
(mild or severe?) form
toxin (more or less?) well absorbed
main symptom is ______________
(Mildly or highly ?) infectious
•Cutaneous diphtheria
_______ or _______ ———-
Mild; less
nasal discharge ; highly
Acute or chronic ulcers
Complications of Diphtheria
Cardiovascular - _________
Neurological - _________ -______ or ______ nerves
Renal – manifest as ____________
Bronchitis, _______pneumonia, otitis media.
myocarditis
polyneuritis; cranial or peripheral
albuminuria
bronchopneumonia
Complications
Neurological - polyneuritis - cranial or peripheral nerves -
results in ______ of ________ , _______ of fluids, _______ and ———- paralysis
paralysis of soft palate
regurgitation
diaphragmatic and limb
Diagnosis
• Treatment based on _________ and not __________
clinical suspicion
laboratory diagnosis
Diagnosis
• Lab diagnosis is important for _________
epidemiology
Laboratory diagnosis
_______ stain, ______ stain, ________ stain
Culture: ________ slant , ______ agar
Gram; Neisser’s; Albert’s
Loefflers; Tellurite
Laboratory diagnosis
Biochemical tests
Ferments ______ (with or without?) gas
never ferments _________
glucose
without
saccharose
Virulence test
–invivo :__________
-invitro: _______ test , tissue _______
molecular biology tests
laboratory animal
Elek
culture
Virulence test: Elek test
-Most __________
-_____________ test
commonly used
Gel diffusion precipitin
Treatment
_______ to prevent spread
________–on clinical suspicion
_________ for laryngeal obstruction
Isolate
Antitoxin
Tracheostomy
