Tetanus, botulism and LMND Flashcards
Which one Is true about Tetanus:
a. Dogs are 10 times more resistant than cats
b. Cats are 20 times more resistant than dogs
c. Cats are more sensitive than horses
d. Dogs are 600 times more resistant than horses
d. Dogs are 600 times more resistant than horses
Clostridium tetani is:
a. A static, gram negative , non-encapsulated, anaerobic, spore forming cocci
b. A motile, gram positive, encapsulated, aerobic, rod
c. A motile, gram positive, non-encapsulated, anaerobic, rod.
d. A static, gram negative, encapsulated, aerobic, cocci.
c. A motile, gram positive, non-encapsulated, anaerobic, rod.
What is the suitable environment for the Clostridium tetani and its spores?
Natural habitat is in moist, fertile soil, however, they can survive indefinitely in dusty indoor environment.
Spores are resistant to boiling water and autoclave temperature of 120degrees 20 min.
Vegetative phase of this bacterium is susceptible to chemical and physical inactivation.
What are the two exotoxins secreted by the tetanus bacillus and what is their pathogenesis?
Tetanolysin: locally damaging otherwise viable tissue surrounding the infected area and optimizing the conditions for bacterial multiplication.
Tetanospasmin: leads to clinical signs of tetanus. It has two chains,
The heavy chain is responsible for internalization, cytosolic translocation and fast retrograde axonal transport of the light chain.
The light chain is the neurotoxin and acts pre-synaptically to prevent neurotransmitter release from the neurons by cleaving and inactivating synaptobrevin (“docking” protein necessary for the export of intracellular vesicles containing the neurotransmitter).
The toxin can lead to cross-linking of synaptic vesicles to cytoskeleton, further preventing neurotransmitter release.
The light chain becomes activated after internalization into inhibitory neurons; at this stage the toxin is no longer accessible for neutralisation by the antitoxin.
Toxin affects inhibitory interneurons, inhibitory release of glycine and GABA
How does the parasympathetic and somatic cranial nerve nuclei exacerbate trismus?
Increased salivation, increased bronchial secretions and increased respiratory rate.
Why is aspiration pneumonia a main complication of tetanus (additionally to previous mentioned problems?
Regurgitation and gastroesophageal reflux can result rarely from oesophageal hiatal hernia and megaesophagus.
What is the mortality rate range for tetanus as per Ettinger/SACCM?
a. 15% - 60%
b. 8% - 50%
c. 5% - 30%
d. 10% - 40%
b. 8% - 50%
Describe handling and nursing care needed in a severe case of tetanus
Dark quiet environment Cotton wool in ear canal Ocular care Minimal handling (treatment coordinated at same time) Feeding tube: Gastrotomy-gastrojejunostomy vs oesophageal vs NG. Urinary catheter Potential Tracheostomy tube Mechanical ventilation
What is the tetanus severity classification proposed in dogs?
Class I: only facial signs of tetanus
Class II: generalized rigidity or dysphagia, with or without class I signs
Class III: class I or II signs and are recumbent or have seizures.
Class IV: class I, II, or III as well as abnormal heart rate, respiratory rate or blood pressure measurements.
Mention differential diagnoses of tetanus
Immune-mediated polymyositis, strychnine intoxication, spinal trauma, hypocalcemia, meningoencephalitis.
Is there any diagnostic test to achieve definitive diagnosis?
Antibodies to tetanospasmin, PCR (not available in vet medicine)
Gram stain from an open wound can identify Gram + rods and dark-staining spheric endospores. (not specific)
What are the three treatment strategies for dogs and cats?
Neutralize the toxins present in the body outside the CNS (Antitoxin)
Organisms present in the body should be destroyed to prevent further toxin release.
The effect of the toxin already in the CNS should be minimized
With respect to tetanic antitoxin: (which one is true)
Anti-tetanus equine serum is more likely to cause a reaction than human tetanus immune globulin if given intravenously
There has been no significant benefit in survival, severity of clinical signs or duration of clinical signs shown for dogs treated with antitoxin.
However, the has been demonstrated a benefit of earlier administration on progression of clinical signs
IM administration is preferred due to the high incidence of anaphylaxis (F)
There has been no significant benefit in survival, severity of clinical signs or duration of clinical signs shown for dogs treated with antitoxin.
Anti-tetanus equine serum is more likely to cause a reaction than human tetanus immune globulin if given intravenously (F- the other way around)
However, the has been demonstrated a benefit of earlier administration on progression of clinical signs (F)
IM administration is preferred due to the high incidence of anaphylaxis (F)
Which antibiotics are recommended to kill C.tetani? For how long should they be given?
Metronidazole is superior. 7-10 mg/kg PO for 10 days
Penicillin G
Also clindamycin, tetracycline or doxycycline
Which drugs are recommended to maintain sedation ?
GABA agonists in general: Benzodiazepines, phenobarbital, acepromazine.
If very severe propofol. (mechanical ventilation), neuromuscular blockers
Botulinum toxin has been suggested!
