Clostridium tetani: Difference between revisions
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Clostridium tetani
(Created page with "== Background == * Ubiquitous soil organism * Acquired either by direct inoculation or via umbilical stump in neonates === Pathophysiology === * Toxin blocks inhibitory int...") Â |
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− | == |
+ | ==Background== |
− | * |
+ | *Ubiquitous soil organism |
− | * |
+ | *Acquired either by direct inoculation or via umbilical stump in neonates |
− | === |
+ | ===Microbiology=== |
+ | *Thin [[Stain::Gram-positive]] [[Shape::bacillus]], with terminal spore (drumstick appearance), with numerous spores |
||
− | * Toxin blocks inhibitory interneurons in the spinal cord and autonomic nervous system |
||
+ | ===Pathophysiology=== |
||
− | == Clinical Manifestations == |
||
+ | *The toxin, tetanospasmin, is a zinc-dependent matrix metalloproteinase that blocks inhibitory interneurons in the spinal cord and autonomic nervous system |
||
− | * Incubation period of [[Usual incubation period::3 to 21 days]] |
||
− | * Followed by generalized tetanus, with tetanic spasms with even minimal external stimulus |
||
− | * Lockjaw, risus sardonicus, opisthotonus, abdominal rigidity, and eventually apnea |
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+ | ===Epidemiology=== |
||
− | === Prognosis and Complications === |
||
+ | *Rare in developed countries (0.1 to 0.2 cases per million people in the US) |
||
− | * 30% mortality |
||
+ | *Cases and deaths have decreased substantially after introduction of vaccination |
||
− | * Can cause bony fractures, asphyxia, hematomas, and rhabdomyolysis |
||
+ | ==Clinical Manifestations== |
||
− | == Diagnosis == |
||
+ | *Incubation period of [[Usual incubation period::3 to 21 days]], which is followed by a period of onset to the first generalized spasm |
||
− | * Baseline IgG serology; if positive, then they are tetanus-immune and it rules out the diagnosis |
||
+ | **Shorter incubation period and period of onset are both associated with poorer prognosis |
||
− | * Send wound swab or tissue for culture or PCR |
||
+ | ===Generalized Tetanus=== |
||
− | == Management == |
||
+ | *Disease is characterized by tonic spasms |
||
− | * Tetanus antitoxin or IVIg |
||
+ | *Classically starts with muscles of the jaw, causing trismus, lockjaw, and risus sardonicus, and sometimes abdominal rigidity |
||
− | * Wound care with debridement |
||
+ | *Progresses to generalized spasm, which involves decorticate posturing with opisthotonus, arm flexion, and leg extension |
||
− | * Antibiotics |
||
+ | **Spasms may be triggered by sensory stimuli |
||
− | * Vaccination on recovery |
||
+ | **May cause airway obstruction, and may involve diaphragm, both of which can be fatal |
||
+ | *Disease progresses over two weeks, with complete recovery taking another month |
||
+ | ===Localized Tetanus=== |
||
+ | |||
+ | *Rigidity of muscles near the site of inoculation |
||
+ | *May be mild and often resolves spontaneously over time |
||
+ | *May progress to generalized tetanus |
||
+ | |||
+ | ===Cephalic Tetanus=== |
||
+ | |||
+ | *Localized tetanus involving the cranial nerves following a head injury |
||
+ | |||
+ | ===Neonatal Tetanus=== |
||
+ | |||
+ | *Caused by infection of the umbilical stump, due to contamination in the context of unimmunized mothers |
||
+ | *Presents with generalized weakness and failure to nurse, followed eventually by rigidity and spasms |
||
+ | *Very high mortality (90%) |
||
+ | |||
+ | ===Prognosis and Complications=== |
||
+ | |||
+ | *30% mortality |
||
+ | *Can cause bony fractures, asphyxia, hematomas, and rhabdomyolysis |
||
+ | |||
+ | ==Diagnosis== |
||
+ | |||
+ | *Almost entirely a clinical diagnosis, due to low yield of organism and toxin from clinical samples |
||
+ | *Baseline IgG serology; if positive, then they are tetanus-immune and it rules out the diagnosis |
||
+ | *Send wound swab or tissue for culture or PCR |
||
+ | |||
+ | ==Management== |
||
+ | |||
+ | *Supportive care |
||
+ | **Early intubation for airway protection |
||
+ | **[[Benzodiazepines]] to manage muscle spasms |
||
+ | ***Rarely, need to escalate to neuromuscular blockage |
||
+ | **May need α- or β-adrenergic blockade with [[labetalol]] to manage autonomic dysfunction |
||
+ | ***Avoid unopposed α effect, which can cause severe hypertension |
||
+ | **Increased nutritional support, given the high metabolic demands of the illness |
||
+ | *Immunization |
||
+ | **Tetanus antitoxin, tetanus immune globulin (TIg), or [[IVIg]] can shorten the duration of illness. Administer as early as possible and within 24 hours. |
||
+ | **Vaccination with toxoid vaccine, within 24 hours, into a different limb. |
||
+ | *[[Metronidazole]] may improve outcomes compared to [[penicillin]] |
||
+ | *Wound care with debridement as indicated, though it does not alter the course of the disease |
||
+ | |||
+ | ==Prevention== |
||
+ | |||
+ | ===Vaccination=== |
||
+ | |||
+ | *The tetanus toxoid vaccine is part of the routine childhood immunization |
||
+ | |||
+ | ===Postexposure Prophylaxis=== |
||
+ | |||
+ | *Postexposure prophylaxis involves either tetanus vaccination, tetanus immunoglobulin (TIg), or both |
||
+ | |||
+ | {| class="wikitable" |
||
+ | !Immunization Status |
||
+ | !Wound |
||
+ | !Vaccine |
||
+ | !Immunoglobulin |
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+ | |- |
||
+ | | rowspan="2" |did not complete childhood series, |
||
+ | or unknown |
||
+ | |clean, minor injury |
||
+ | |yes |
||
+ | |no |
||
+ | |- |
||
+ | |all others |
||
+ | |yes |
||
+ | |yes |
||
+ | |- |
||
+ | | rowspan="2" |completed childhood series |
||
+ | |clean, minor injury |
||
+ | |only if last was given ≥10 years ago |
||
+ | |no |
||
+ | |- |
||
+ | |all others |
||
+ | |only if last was given ≥5 years ago |
||
+ | |no |
||
+ | |} |
||
{{DISPLAYTITLE:''Clostridium tetani''}} |
{{DISPLAYTITLE:''Clostridium tetani''}} |
||
− | [[Category:Infectious diseases]] |
||
[[Category:Gram-positive bacilli]] |
[[Category:Gram-positive bacilli]] |
Latest revision as of 09:49, 15 October 2020
Background
- Ubiquitous soil organism
- Acquired either by direct inoculation or via umbilical stump in neonates
Microbiology
- Thin Gram-positive bacillus, with terminal spore (drumstick appearance), with numerous spores
Pathophysiology
- The toxin, tetanospasmin, is a zinc-dependent matrix metalloproteinase that blocks inhibitory interneurons in the spinal cord and autonomic nervous system
Epidemiology
- Rare in developed countries (0.1 to 0.2 cases per million people in the US)
- Cases and deaths have decreased substantially after introduction of vaccination
Clinical Manifestations
- Incubation period of 3 to 21 days, which is followed by a period of onset to the first generalized spasm
- Shorter incubation period and period of onset are both associated with poorer prognosis
Generalized Tetanus
- Disease is characterized by tonic spasms
- Classically starts with muscles of the jaw, causing trismus, lockjaw, and risus sardonicus, and sometimes abdominal rigidity
- Progresses to generalized spasm, which involves decorticate posturing with opisthotonus, arm flexion, and leg extension
- Spasms may be triggered by sensory stimuli
- May cause airway obstruction, and may involve diaphragm, both of which can be fatal
- Disease progresses over two weeks, with complete recovery taking another month
Localized Tetanus
- Rigidity of muscles near the site of inoculation
- May be mild and often resolves spontaneously over time
- May progress to generalized tetanus
Cephalic Tetanus
- Localized tetanus involving the cranial nerves following a head injury
Neonatal Tetanus
- Caused by infection of the umbilical stump, due to contamination in the context of unimmunized mothers
- Presents with generalized weakness and failure to nurse, followed eventually by rigidity and spasms
- Very high mortality (90%)
Prognosis and Complications
- 30% mortality
- Can cause bony fractures, asphyxia, hematomas, and rhabdomyolysis
Diagnosis
- Almost entirely a clinical diagnosis, due to low yield of organism and toxin from clinical samples
- Baseline IgG serology; if positive, then they are tetanus-immune and it rules out the diagnosis
- Send wound swab or tissue for culture or PCR
Management
- Supportive care
- Early intubation for airway protection
- Benzodiazepines to manage muscle spasms
- Rarely, need to escalate to neuromuscular blockage
- May need α- or β-adrenergic blockade with labetalol to manage autonomic dysfunction
- Avoid unopposed α effect, which can cause severe hypertension
- Increased nutritional support, given the high metabolic demands of the illness
- Immunization
- Tetanus antitoxin, tetanus immune globulin (TIg), or IVIg can shorten the duration of illness. Administer as early as possible and within 24 hours.
- Vaccination with toxoid vaccine, within 24 hours, into a different limb.
- Metronidazole may improve outcomes compared to penicillin
- Wound care with debridement as indicated, though it does not alter the course of the disease
Prevention
Vaccination
- The tetanus toxoid vaccine is part of the routine childhood immunization
Postexposure Prophylaxis
- Postexposure prophylaxis involves either tetanus vaccination, tetanus immunoglobulin (TIg), or both
Immunization Status | Wound | Vaccine | Immunoglobulin |
---|---|---|---|
did not complete childhood series,
or unknown |
clean, minor injury | yes | no |
all others | yes | yes | |
completed childhood series | clean, minor injury | only if last was given ≥10 years ago | no |
all others | only if last was given ≥5 years ago | no |