Epidemiology
- Worldwide incidence 1 million cases per year
- Mortality rate 20-30%
- 第三類法定傳染病 (一週內通報)
- 台灣每年通報 < 20例
Clostridium tetani 破傷風桿菌
- Anaerobic Spore forming gram-positive rod (GPB)
- Soil, Animal feces
- Incubation period : ranges from < 24hr to > 1 month
- Wound
* 70 % related to acute wound : 厭氧環境!
Puncture (生鏽鐵釘), Contaminated, Infected or devitalized wounds
* Less common :
Chronic wounds, ulcers, Wounds in DM, Dental abscesses,
Injection drug abuser, Neonate umbilical stump
* 10% patients with tetanus : no wound
- Exotoxins
1. Tetanolysin
2. Tetanospasmin : Neurotoxin
- Doesn’t cross BBB, but Retrograde intraneuronal transport to CNS
- Prevents the release of the inhibitory neurotransmitters : Glycine + GABA
from presynaptic nerve terminals
- Sympathetic overactivity
- Generalized muscular rigidity, Violent muscular contractions, ANS instability
- 3 types of Tetanus
1. Generalized : 80%
- Neonatal tetanus : Unsterile treatment of the umbilical cord
Weak, irritable, inability to suck
2. Cephalic : injuries to the head or occasionally otitis media, Dysfunction of CN7
3. Local : Rigidity proximal to the injury site
Generalized tetenus
- Pain and stiffness in masseter : Lockjaw, Trismus牙關緊閉, 張口困難
- Stiffness -> Rigidity : Risus sardonicus, Sardonic smile痙笑
- Nerves with short axons affected first
* Descending progression : Face, Neck, Trunk, Extremities
* Dysphagia
* Opisthotonos : flexing of the arms, Clenching of the fists, Extension of the lower extremities
- Mental status is normal !
- Rhabdomyolysis, long-bone fractures
- Respiratory compromise
* Laryngospasm
* Respiratory muscles contraction
- Hypersympathetic state : 2nd week
* Tachycardia, labile hypertension, profuse sweating, hyperpyrexia
Strychnine poisoning 番木鱉鹼 is most closely mimics !
Diagnosis
- Tetanus is diagnosed clinically
- No laboratory tests to diagnose
- Wound culture is of limited value
Treatment
- Immunotherapy
* Human tetanus immunoglobulin (TIG) : neutralizes circulating tetanospasmin and toxin in wound
* Around the wound, before debridement
< TIG 是被動免疫 >
- Wound : debridement
- Antibiotics : limited value but are traditionally administered
* Parenteral metronidazole
* Do not give penicillin, may potentiate tetanospasmin
- Neuromuscular blockade : Prolonged neuromuscular blockade
- Muscle relaxant : midazolam
- Autonomic dysfunction
- Immunization : infection does not confer immunity
recover from tetanus must receive active immunization
破傷風病癒後並不會產生終身免疫, 仍有可能二次感染, 因此病癒後仍需進行預防注射
DTaP-Hib-IPV : 2, 4, 6, 18個月
Tdap-IPV : 5歲至國小入學前接受一劑
感染 : TIG + Toxoid (Present + 6W + 6M)
暴露後預防 :
- 基本上都有注射 > 3 次類毒素, 所以不需要 TIG
- 疫苗效力 10 年, 乾淨傷口15 歲以下不太需要考慮
髒的傷口 10 歲要考慮
髒的傷口 :
* Wounds > 6 hours old
* Contaminated by soil, saliva, feces, dirt
* Puncture or crush wounds
* Avulsions
* Wounds from missiles, burns, or frostbite.
- Contraindications
* Serious allergic reaction, Encephalopathy, Guillain-Barré syndrome ≤6 weeks
Arthus hypersensitivity reaction
= Passive immunization with tetanus immunoglobulin
主動免疫疫苗:
(1) DTaP-Hib-IPV 五合一疫苗
(2) DT 白喉, 破傷風混合疫苗
(3) Td 破傷風, 減量白喉混合疫苗
(4) Toxoid 單一破傷風類毒素
被動免疫血清:
(1) TAT 破傷風抗毒素 : 馬血清來源, 應注意過敏
(2) TIG 破傷風免疫球蛋白