Tetanus. Immunotherapy. Flashcards
what is the etiology of tetanus ?
Clostridium tetani:
what are the characteristics od Clostridium tetani
a gram-positive,
obligate anaerobic,
spore-forming rod - spores are resistant to heat, desiccation, and disinfectants
Produces neurotoxins tetanospasmin
and tetanolysin
tetanolysin = causes hemolytic effects. Its exact function is unknown.
tetanospasmin - A neurotoxin produced by Clostridium tetani. The toxin undergoes retrograde axonal transport back to the CNS, binds inhibitory neurotransmitters, and causes the tonic-clonic spasms and autonomic instability
Ubiquitous (especially animal feces and soil)
what is the transmission of tetanus ?
Clostridial spores contaminate a wound (e.g., through dirt, saliva, feces).
neonatal tetanus - Occurs in infants of inadequately immunized mothers after unsterile management of the umbilical stumpt
it is said not to give honey to babies, because it could be present in
honey
what are the risk factors for tetanus
- Localized ischemia, necrosis, foreign bodies and/or coinfection with other bacteria predispose to infection.
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Wounds with compromised blood supply create anaerobic conditions that are required for the germination and multiplication of C. tetani.
such as
- Deep, penetrating wounds
(e.g., knife, gunshot, animal bites)
- Open fractures
- Surgical procedures (e.g., bowel, biliary tract, or dental surgery)
- Burns
- Umbilical stump infections
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Groups with a higher risk: non-immunized individuals,
those with diabetes,
neonates,
people who inject drugs (PWID), certain patient groups (i.e., postsurgical, obstetric, dental)
epidemiology of tetanus ?
more in developing countries
in Sub-Sahara and South Asia
Groups with a higher risk: non-immunized individuals,
those with diabetes,
neonates,
people who inject drugs (PWID), certain patient groups (i.e., postsurgical, obstetric, dental)
pathophysiology of Clostridium tetani?
spores contaminate a wound
→ only when they have reached an anaerobic environment, they can
replicate, grow, and release tetanus toxin
2 toxins are produced by C. Tetani:
TETANOLYSIN - hemolysin with no and as cardiotoxic effects
TETANOSPASMIN –
has 2 subunits: A and B
tetanolysin = causes hemolytic effects. Its exact function is unknown.
The toxin undergoes retrograde axonal transport back to the CNS (spinal cord) , binds inhibitory neurotransmitters (GABA and glycine ) , and causes uninhibited activation of alpha motor neurons →
tonic-clonic spasms in response to normal stimuli such as noises or lights
and autonomic hyperactivity
hypersympathetic state because there is failure to inhibit adrenal release
of catecholamine
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Neurotoxins (not the pathogen itself) cause tetanic contractions.
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localised tetanus
generalised tetanus - the toxin released at the wound spreads
through the lymphatics and blood to multiple nerve terminals
what is the incubation period of Clostridium tetani
3–21 days (average: ∼ 10 days)
what are the clinical manifestation of Clostridium tetani?
1) localized tetanus: when only the nerves supplying the affected muscle
are involved
2) generalized - the toxin released at the wound spreads
through the lymphatics and blood to multiple nerve terminals
3) cephalic,
4) and neonatal
what are the GENERALISED TETANUS clinical manifestations ?
Generalized tetanus
initial symptom: flu-like symptoms,
generalized headache
and fatigue,
painful muscle spasms and rigidity - Occur spontaneously or
triggered by acoustic, optic, or mechanic stimulation
1) RISUS SARDONICUS
sustained facial muscle spasm
sardonic grin and raised eyebrows
(increased tone in the orbicularis oris)
2) trismus
(“lockjaw” masseter rigidity) due to spasm of N.trigeminus,
3) Opisthotonus:
backward arching of spine, neck, and head caused by spasms of the back muscles
4) Neck stiffness
5) Abdominal rigidity - may mimic acute abdomen
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disease can progress for 2 weeks
what are life threatening complications ?
Laryngospasm and/or respiratory muscles spasms → respiratory failure
Autonomic dysfunction (Tachycardia may alternate with bradycardia, and hypertension with hypotension.) → circulatory arrest and shock
what is the incubation period for neonatal tetanus ?
5–8 days after birth, but the incubation period can take up to several weeks
what are the NEONATAL TETANUS CLINICAL manifestations ?
rapid onset of symptoms as axonal length in infants is shorter than in adult
Difficulty opening the mouth and feeding due to trismus and risus sardonicus Muscle stiffness opisthotonus Clenched hands
90% mortality rate, in survivors: developmental delay
what are the clinical manifestation of LOCALISED TETANUS
painful muscle contractions in areas surrounding the injury site only
often resolves spontaneously
can progress to generalised tetanus
what is the incubation period for cephalic tetanus ?
1-2 days
what are the clinical manifestation of CEPHALIC TETANUS
patients with open head or neck injuries.
Initially, only affects cranial nerves (especially flaccid paralysis of CN VII), which can be mistaken for stroke.
