Tetanus and Botulism Flashcards

Question

What animals are susceptble to tetanus?

Answer 1

1. Almost all mammals are susceptible to this disease - Birds are quite resistant; the lethal dose for pigeons and chickens is 10,000-300,000 times greater (on a body wt basis) than that for horses 2. Horses are the most sensitive of all species

Answer 2

- C tetani, an anaerobe with terminal, spherical spores - is found in soil and intestinal tracts

Answer 3

Introduced into the tissues through wounds, particularly deep puncture wounds, that provide a suitable anaerobic environment Note: Sometimes, the point of entry cannot be found because the wound itself may be minor or healed

Answer 4

- The spores of C tetani are unable to grow in normal tissue or even in wounds if the tissue remains at the oxidation-reduction potential of the circulating blood - Suitable conditions for multiplication occur when a small amount of soil or a foreign object causes tissue necrosis.

Answer 5

1. The bacteria remain localized in the necrotic tissue at the original site of infection and multiply 2. As bacterial cells undergo autolysis, the potent neurotoxin is released

Answer 6

- Synthesized by C. tetani growing on either deep contaminated wounds or wounds containing foreign objects - The neurotoxin is a zinc-binding protease that cleaves synaptobrevin, a vesicle-associated membrane protein - Toxin coded on a plasmid - Has 2 components (tetanospasmin and tetanolysin) - When produced the toxin is inactive: Activity induced by proteolytic enzymes

Answer 7

Toxin absorbed by the motor nerves in the area of entry and passes up the nerve tract to the spinal cord

Answer 8

If more toxin is released at the site of the infection than the surrounding nerves can take up, the excess is carried off by the lymph to the bloodstream and thus to the CNS where it causes descending tetanus

Answer 9

1. The toxin causes spasmodic, tonic contractions of the voluntary muscles by interfering with the release of neurotransmitters from presynaptic nerve endings 2. The spasms may be so severe as to cause bone fractures 3. Spasms affecting the larynx, diaphragm, and intercostal muscles lead to respiratory failure 4. Involvement of the autonomic nervous system results in cardiac arrhythmias, tachycardia, and hypertension

Answer 10

Toxin reaching the brain inhibits synthesis of glycine - This result in contractions of antagonistic muscles - The contractions can be severe to break the muscles or bones - Uncontrolled contractions can affect the respiratory system

Answer 11

varies from one to several weeks but usually averages 10-14 days

Answer 12

1. Localized stiffness, often involving the masseter muscles and muscles of the neck, the lower limbs, and the region of the infected wound; 2. General stiffness becomes pronounced ~1 day later, and tonic spasms and hyperesthesia become evident 3. Reflexes increase in intensity, and the patient is easily excited into more violent, general spasms by sudden movement or noise 4. Spasms of head muscles cause difficulty in apprehension and mastication of food, hence the common name, lockjaw 5. Spasms of the neck and back muscles cause extension of the head and neck 6. Sweating is common

Answer 13

1. Any wound that results in a break in the skin should be cleaned with soap and running water 2. Antibiotics to kill the bacteria, tetanus booster shot, if necessary, and occasionally, antitoxin to neutralize the toxin 3. supportive measures 4. sedatives such as diazepam (Valium) to control muscle spasms 5. IV rehydration because, as muscles spasm constantly, increased metabolic demands are placed on the body 6. Tetanus vaccine given in infancy and booster vaccine to at risk population