Tetanus is a vaccine preventable disease. The initial symptoms are trismus (lockjaw), difficulty swallowing, painful muscular spasms, and rigidity of abdominal muscles. The average incubation period is 8 days.
CASES/YEAR
36 (US); 180,000 (Global)
OTHER NAMES
Lockjaw; Clostridium tetani infection;
INCUBATION
3-21 days (average 8 days); Only 1-2 days for cephalic tetanus (rare); [Cecil, p. 1895]
INITIAL SYMPTOMS
Trismus (lockjaw), difficulty swallowing, painful muscular spasms, and rigidity of abdominal muscles; [CCDM]
PRECAUTIONS
Standard; "Not transmitted from person to person." [CDC 2007 Guideline for Isolation Precautions]
COMMENTS
FINDINGS:
The toxin produced by these anaerobic bacteria causes painful muscular spasms. Rigidity of the abdominal muscles has been described as a common first sign of the disease. In localized tetanus, rigidity is confined to the area of injury. [CCDM, p. 607] Tetanus toxin can cause ptosis, ophthalmoplegia, and weakness as well as rigidity. [Guerrant, p. 285, 1003] Symptoms include headache, dysphagia, opisthotonus, sweating, cyanosis, restlessness, and speech impairment. Patients are initially awake and oriented. Muscle spasms eventually lead to coma, respiratory failure, and death. [Merck Manual, p. 1470] The 4 types of tetanus are generalized, localized, cephalic, and neonatal. The generalized tetanus often begins with trismus (lockjaw) and risus sardonicus (grinning and raised eyebrows from spasms of facial muscles). The airway may be obstructed during spasms. Cephalic tetanus, which usually follows a head wound, often causes facial paralysis. [PPID, p. 2950-1] Local tetanus and cephalic tetanus are rare. [Cecil, p. 1895] Arrhythmias, blood pressure oscillations, hyperthermia, and urinary retention may occur as a result of autonomic nervous dysfunction. [ID, p. 1797] Spasms are often triggered by external stimuli. [Cohen, p. 211]
EPIDEMIOLOGY:
The incidence of tetanus is higher in developing countries--more contact with animal excreta and less use of tetanus vaccine. Outbreaks have been reported among injecting drug users. [CCDM, p. 608] Tetanus is the leading cause of neonatal mortality in parts of the world with low vaccination rates and high umbilical stump infection rates. [Guerrant, p. 286] Between 2001 and 2008, 233 cases were reported in the USA with most patients older than 60. [PPID, p. 2948] Mortality rate is about 50% worldwide. [Merck Manual, p. 1471] Without ventilatory support, respiratory failure is the most common cause of death. [Harrison ID, p. 454]
DIFFERENTIAL DIAGNOSIS:
Serum/urine should be tested for strychnine, which can cause a similar illness. Dystonic reactions usually cause lateral neck turning unlike that seen in tetanus. Anticholinergic drugs such as benztropine or diphenhydramine rapidly clear dystonic reactions. [PPID, p. 2951]
DIAGNOSTIC
Clinical; "Attempts at laboratory confirmation are of little help." [CCDM]
SIGNS & SYMPTOMS
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>fever
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>myalgia
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E dysphagia
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E pharyngitis
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G constipation
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H leukocytosis
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N headache
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N muscle weakness
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N opisthotonus
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N seizure
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N stiff neck
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*acute renal failure
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*cranial neuropathy
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*paralysis
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*pneumonia
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*rhabdomyolysis
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*stupor, coma
ENTRY
Needle (Includes Drug Abuse), Scalpel or Transfusion, Skin or Mucous Membranes (Includes Conjunctiva)
SOURCE
Fecally Contaminated Soil, Animal Excreta, Soil or Dust (Ingesting or Inhaling)
RISK FACTORS
- Fail to complete immunizations
- Injection drug users
- Travel to endemic area
TREATMENT
Human tetanus immune globulin (HTIG) shortens the course of tetanus. [PPID, p. 2952]
REFERENCES FOR CASES/YEAR
1. (US) Published in MMWR 2011 = 36;
2. (Global) Estimated 180,000 cases/year; About 290,000 cases in 2006; >1 million cases in the early 1980s when much lower vaccination coverage; [Harrison ID, 2nd Ed, p. 467]