Clostridium tetani: Difference between revisions

Latest revision as of 13:49, 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
did not complete childhood series, or unknown	all others	yes	yes
completed childhood series	clean, minor injury	only if last was given ≥10 years ago	no
completed childhood series	all others	only if last was given ≥5 years ago	no

@@ Line 1: / Line 1: @@
-== Background ==
+==Background==
-* Ubiquitous soil organism
+*Ubiquitous soil organism
-* Acquired either by direct inoculation or via umbilical stump in neonates
+*Acquired either by direct inoculation or via umbilical stump in neonates
-=== Pathophysiology ===
+===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
+===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
+|-
+| 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''}}
-[[Category:Infectious diseases]]
 [[Category:Gram-positive bacilli]]