Tetanus

Tetanus is an acute infection caused by Clostridium tetani entering wounds, growing anaerobically and producing a neurotropic exotoxin that causes generalized muscle rigidity. Severe cases die of laryngeal spasm or secondary pneumonia; neonatal tetanus from umbilical infection has high mortality. WHO global immunization programs notwithstanding, nearly a million cases occur yearly worldwide with hundreds of thousands of neonatal deaths.

Common Symptoms

Coma; myalgia; opisthotonus; dyspnea; risus sardonicus; convulsions; abdominal muscle rigidity; postoperative tetanus

Causes and Pathogenesis

C. tetani is ubiquitous in soil and feces; neither bacilli nor toxin can penetrate intact skin, so tetanus follows wounds—open injuries, fractures, burns, even tiny splinter/rust-nail punctures. It also follows unsterile neonatal cords and inadequately disinfected abortions. The presence of bacilli does not imply disease; anaerobic, narrow, ischemic, necrotic, poorly drained wounds favor it. Calcium chloride in soil and aerobic pyogenic co-infection promote local necrosis and anaerobic growth. C. tetani (Clostridium tetani) is an obligate anaerobic spore-forming rod 2-5 × 0.3-0.5 µm, peritrichously flagellated, motile, Gram-positive (may stain Gram-negative on wound smears). Vegetative forms are killed by disinfectants/boiling; terminal drumstick spores survive years in soil and require autoclaving. Toxin splits by trypsin into α/β/γ: tetanospasmin, tetanolysin, and fibrinolysin; tetanospasmin is plasmid-encoded, 160 kDa (heavy chain 105, light chain 55), heat-labile (65°C/30 min); light chain is a zinc endopeptidase; heavy chain binds neuronal receptors and mediates internalization. Non-invasive, toxin binds gangliosides at nerve endings and ascends via spinal roots to anterior horn/brainstem; also lymphohematogenous. Normally, excitatory flexor motor neurons simultaneously activate inhibitory interneurons (releasing glycine/GABA) to relax extensors. Tetanospasmin selectively blocks inhibitory neurons, causing simultaneous strong flexor/extensor contraction; it also blocks neuromuscular transmission, causing sustained hypertonia and spasm—trismus and opisthotonus.

Treatment

Drug therapy, supportive therapy

Preventive Measures

Routine prevention: (1) Wound care—clean minor wounds with water/soap, apply iodine/Yunnan Baiyao, cover; large wounds: dress and seek hospital care. (2) Maternal hygiene. (3) Toxoid vaccination. (4) Chinese herbal medicine. Health education: (1) Active immunization: DPT is part of China's EPI for 3-5-month-olds (0.25, 0.5, 0.5 ml at 4-week intervals), boosters at 1.5-2 years and every 2 years until school; unimmunized adults (military, high-risk occupations) receive adsorbed purified toxoid (0.5 ml IM ×2, 4-8 weeks apart, then 0.5 ml booster every 5-10 years). In endemic areas, pregnant women receive 0.5 ml toxoid ×3 monthly, last dose 1 month before delivery; WHO target of global elimination by 2000 was not met; only ~60% of adults have protective antibodies. (2) Passive immunization: TAT 1000-2000 U IM (skin-test first, desensitize if positive), protects ~10 days; or HTIG 500-1000 U IM, protects 3-4 weeks; start active immunization simultaneously. (3) Wound care: thorough debridement and maternal asepsis; deep/dirty wounds need antibiotics (best within 6 h, 3-5 days) to control aerobic pyogens and avoid anaerobic microenvironments.

Department to Visit

It is recommended to visit the General Surgery department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.