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Level 2 of 6Must-remember

Tetanus: recognition, spasm control and prevention

Assess, manage and stay safe — enough on its own

The card — assess, manage, caution

Assessment— look, ask, measure

  • Ask about a wound and what kind: puncture from a thorn, nail, splinter or needle; a wound contaminated with soil, dust or faeces; burn, crush injury, open fracture or gunshot wound; chronic leg or diabetic foot ulcer, pressure injury or gangrene; injection site in a person who injects drugs; obstetric, surgical or unsafe-abortion wound; the umbilical stump in a newborn; a discharging middle ear or a dental focus.
  • Accept that there may be no wound at all: in roughly one in five cases no portal of entry is ever identified, and this is never an argument against the diagnosis or against treatment.
  • Establish the two prognostic intervals at first contact: the incubation period (injury to first symptom) is 5 days to 15 weeks, averaging 8–12 days, and the onset time (first symptom to first generalised spasm) is a separate interval — an incubation period under 7 days or an onset time under 48 hours predicts severe disease and a need for mechanical ventilation.
  • Ask about immunisation: most cases occur in unvaccinated individuals, so ask whether a primary course was ever completed and when the last booster was given — the absence of any immunisation is itself an adverse marker.
  • Test for trismus (lock jaw): ask the patient to open the mouth, and if they cannot admit two of their own fingers between the incisors that is trismus; never force the jaw.
  • Look for risus sardonicus: spasm of the facial and periorbital muscles raising the eyebrows and drawing the lips back over the teeth in a fixed involuntary grin — the patient is not smiling, they are frightened and fully aware.
  • Look for generalised rigidity: neck stiffness, dysphagia, irritability, hyperreflexia, rigidity of trunk and limbs, and a board-like abdomen that has no pain, no tenderness on distraction and no peritoneal history.
  • Watch for reflex spasms: sudden, violent, agonisingly painful generalised tonic contractions lasting seconds to minutes with opisthotonus, arms flexed and legs extended, easily precipitated by noise, light, touch or handling.
  • Confirm that consciousness is entirely preserved: there is no confusion, no drowsiness, no focal deficit and normal sensation — rigidity with a fully alert patient is tetanus, rigidity with drowsiness, confusion or fever is meningitis, encephalitis or a drug-induced syndrome until proved otherwise.
  • Measure and record the vital signs with their cut-offs: temperature above 38.4 °C is an adverse marker, heart rate above 120/min in an adult or above 150/min in a neonate is adverse, respiratory rate above 30/min marks moderate and above 40/min severe disease, and swinging blood pressure, sweating or arrhythmia marks autonomic instability.
  • Do a bedside glucose and send corrected calcium and magnesium: all are normal in tetanus, and hypocalcaemic tetany with carpopedal spasm, perioral paraesthesiae and a positive Chvostek or Trousseau sign is an immediately reversible mimic.Not available at your setup — Serum electrolytes.
  • Grade severity with the Ablett classification: I mild trismus and spasticity with no spasms, no dysphagia and no respiratory embarrassment; II moderate trismus, rigidity, short-lived spasms, mild dysphagia and respiratory rate over 30/min; III severe trismus, generalised rigidity, prolonged spasms, severe dysphagia, respiratory rate over 40/min, apnoeic spells and heart rate over 120/min; IV grade III plus violent autonomic instability.
  • Score the Dakar system at 24–48 hours — one point each for incubation period under 7 days, onset time under 2 days, portal of entry in umbilicus, burn, uterus, open fracture, surgical wound or intramuscular injection, spasms present, fever above 38.4 °C, and heart rate above 120/min in an adult or above 150/min in a neonate; 0–1 mild, 2–3 moderate, 4 severe, 5–6 very severe.
  • Recognise the danger signs demanding immediate airway assessment: any spasm of jaw, larynx, neck or respiratory muscles; apnoeic, cyanotic or desaturating episodes; inability to swallow saliva; a rising respiratory rate or rising arterial carbon dioxide; clinical exhaustion; an escalating benzodiazepine requirement; autonomic instability; and any case of cephalic or neonatal tetanus.
  • Know the other three clinical forms: localised tetanus (pain, stiffness and increased tone confined to muscles around the wound, recovery usual but it may generalise at any time), cephalic tetanus (cranial nerve palsies, characteristically of the seventh nerve, often with trismus, usually after a head or facial wound or a chronically discharging middle ear), and neonatal tetanus (presenting in the first two weeks of life, most often days 3 to 14, with failure to thrive, poor sucking, grimacing and irritability then intense rigidity and spasms — mortality approaches 100%).
  • Consider the mimics before committing: acute dystonic reaction from phenothiazines, metoclopramide or haloperidol (the commonest misdiagnosis, reversed within minutes by an intravenous anticholinergic); strychnine poisoning (complete muscular relaxation between spasms, onset within 15–30 minutes of ingestion); bacterial meningitis or encephalitis (impaired consciousness); hypocalcaemic tetany; dental abscess, quinsy, parotitis or temporomandibular disorder (trismus alone); neuroleptic malignant syndrome; serotonin syndrome; stiff person syndrome; and rabies (hydrophobia, fluctuating consciousness, no trismus).

Management— do this, in order

  • Nurse the patient at once in a quiet, isolated, well-ventilated, darkened room: reflex spasms are precipitated by noise, light and handling, so minimising stimulation measurably reduces drug requirement and the frequency of laryngeal spasm — this is treatment, not comfort.
  • Assess and protect the airway before it is lost: intubate and ventilate early for any spasm involving the larynx, inability to swallow secretions, a rising PaCO₂, exhaustion, or the need for sedation deep enough to abolish spasms; treat this as a difficult airway, since trismus may prevent mouth opening and laryngoscopy provokes laryngospasm, and have a plan for a surgical airway.Doctor / NurseNot available at your setup — Endotracheal intubation kit.
  • Draw the pre-treatment serum sample first if it takes only seconds — serum for anti-tetanus toxoid antibody (protective concentration conventionally at least 0.1 IU/mL) is worthless once immunoglobulin has been given, and there is only one opportunity.
  • Give human tetanus immunoglobulin (HTIG) as soon as possible without waiting for any investigation: 500 units IM within the first 24 hours of presentation for established tetanus (Kumar and Clark specify 250 units; doses of 3,000–6,000 units are also widely quoted but higher doses have not proved superior); in children and neonates the dose is not weight-based — give the same 500 units, splitting the volume between two sites in a small infant.Doctor / Nurse
  • Where HTIG is unavailable use human normal immunoglobulin (HNIG) as per preparation despite its lower specific antibody content, and where no human product exists use equine antitoxin 10,000–20,000 units IM or IV after test dosing, accepting a significant risk of anaphylaxis and serum sickness.Doctor / Nurse
  • Give an antibiotic even when no wound is found: metronidazole 500 mg IV every 8 hours for 7–10 days is the drug of choice (paediatric 7.5 mg/kg IV every 8 hours); the alternative is benzylpenicillin 1.2 g (2 million units) IV every 6 hours, paediatric 50 mg/kg IV every 6 hours with an age-dependent neonatal interval.Doctor / Nurse
  • Clean and débride any wound, excising all necrotic tissue and foreign material and leaving it open — but only after antitoxin has been given and the patient is sedated, because manipulating the wound is a powerful spasm trigger.
  • Control spasm with a benzodiazepine as first line: diazepam 5–10 mg IV slowly over at least 2 minutes, repeated every 5–15 minutes and titrated to abolition of spasm, with large cumulative doses often needed; paediatric dose 0.1–0.3 mg/kg IV slowly per dose to a usual maximum of 10 mg, repeated and titrated.Doctor / Nurse
  • Or use midazolam 2–5 mg IV in boluses then an infusion, commonly 5–15 mg/hour (paediatric 0.1 mg/kg IV boluses then infusion), remembering there is no fixed ceiling dose — the dose is whatever abolishes the spasms.Doctor / Nurse
  • Give opioid analgesia; it is not optional: morphine 2.5–5 mg IV repeated and titrated or by infusion (paediatric 0.05–0.1 mg/kg IV titrated), because these spasms are agonisingly painful in a fully conscious patient and morphine also blunts autonomic instability.Doctor / Nurse
  • Add magnesium sulphate as the principal adjunct: 5 g (or 75 mg/kg) IV over 20–30 minutes, then 2 g/hour in adults over 45 kg or 1.5 g/hour if under 45 kg, titrated to spasm control with a target serum magnesium of about 2–4 mmol/L.Doctor / NurseNot available at your setup — Serum electrolytes, Infusion pump.
  • Monitor magnesium clinically: loss of the patellar reflex is the earliest sign of toxicity, followed by respiratory depression and conduction abnormality, and calcium gluconate must be immediately available as the antidote.
  • If spasms persist despite maximal benzodiazepine and magnesium, add a titrated propofol infusion (requires ventilation, risks propofol infusion syndrome at prolonged high dose) or dexmedetomidine, which sedates and sympatholyses without respiratory depression.Doctor / NurseNot available at your setup — Mechanical ventilator, Infusion pump.
  • The definitive answer to uncontrollable spasm is neuromuscular blockade with full mechanical ventilation using vecuronium or rocuronium by infusion — never institute blockade without secure ventilation and never stop the sedation, because a paralysed patient with tetanus is fully aware; avoid pancuronium, which inhibits catecholamine reuptake and worsens autonomic instability.Doctor / NurseNot available at your setup — Mechanical ventilator, Infusion pump.
  • Manage the autonomic storm of the second week with adequate sedation, opioid analgesia, magnesium and minimisation of stimulation: if beta-blockade is needed use short-acting titratable esmolol or labetalol for combined alpha and beta blockade, and clonidine or dexmedetomidine to reduce central sympathetic outflow; treat the sudden hypotension and bradycardia that follow a hypertensive surge with volume, atropine and short-acting vasopressors.Doctor / Nurse
  • Deliver the supportive care that carries most of the benefit: enteral feeding by nasogastric tube inserted under sedation (energy requirements are markedly increased), generous fluid and electrolyte replacement for losses through sweating and salivation, urinary catheterisation for retention from urethral spasm since a distended bladder is itself a spasm trigger, low-molecular-weight heparin for venous thromboembolism prophylaxis, pressure area and joint care, physiotherapy, eye and mouth care and prevention of ventilator-associated pneumonia.
  • Start active immunisation during the illness, because tetanus confers no immunity: give the toxoid in a different limb with a different syringe from the immunoglobulin, as Td two doses 4–6 weeks apart with a third dose 6–12 months later, substituting Tdap for one of the three, then boosters every 10 years for life; in pregnancy use Tdap, which also protects the newborn.Doctor / Nurse
  • Where there is no ventilator, no intensive care and no tracheostomy set: nurse in the darkest quietest space available, cluster all interventions, titrate diazepam to the least dose that abolishes spasms while watching for apnoea, keep the patient in the recovery position with suction to hand, feed by nasogastric tube, catheterise, and arrange transfer early — before the airway is lost — since grade III implies mechanical ventilation and grade IV prolonged ventilation with deep sedation and active autonomic control.

Caution— what harms

  • Never force the jaw open to demonstrate trismus, and never undertake any procedure — suction, nasogastric tube placement, oral examination, wound care — in an unsedated patient, because each is a powerful spasm trigger.
  • Never delay antitoxin, antibiotics or sedation for microbiology or imaging: tetanus is a clinical diagnosis and there is no test that confirms or excludes it; *C. tetani* is isolated in only about a third of proven cases and also from patients who never develop tetanus, so a negative culture excludes nothing and a positive culture confirms nothing.
  • Never give the toxoid in the same limb or with the same syringe as the immunoglobulin, otherwise the antibody neutralises the vaccine — and never assume that surviving tetanus immunises the patient, because the lethal dose of toxin is far below that required to provoke an antibody response.
  • Do not mistake the board-like abdomen for peritonitis: a rigid abdomen with no abdominal pain, no tenderness on distraction and no peritoneal history is muscular spasm, and this error has led to needless laparotomy.
  • Do not take the serum antibody sample after the immunoglobulin: once immunoglobulin is given the sample is uninterpretable, and a protective titre of at least 0.1 IU/mL makes tetanus much less likely but does not exclude it.
  • Benzodiazepines have no fixed ceiling but every increment moves the patient closer to apnoea — secure the airway or be able to secure it immediately before escalating, and remember that apnoea after intravenous diazepam is common in small children; prolonged high-dose infusions add propylene glycol toxicity with diazepam and accumulation of active midazolam metabolites in renal impairment.
  • Prefer metronidazole to penicillin: benzylpenicillin is itself a GABA antagonist and may theoretically aggravate spasm, and antibiotics have no effect on toxin already released — they are an adjunct to antitoxin and débridement, never a substitute.
  • Avoid unopposed beta-blockade in the autonomic storm: propranolol has been associated with sudden death in tetanus, and long-acting vasoactive agents are dangerous in a patient whose haemodynamics oscillate.
  • Do not relax when the spasms come under control: the illness worsens for the first one to two weeks, plateaus for a week then improves over two to four weeks, and autonomic instability peaks in the second week — in the ventilated patient it, rather than airway obstruction, is the leading cause of death.
  • Do not perform the spatula test casually: touching the posterior pharyngeal wall provokes a reflex bite rather than a gag in tetanus, and although reported sensitivity and specificity are high it risks provoking laryngeal spasm in a patient with a marginal airway.
  • Do not miss magnesium toxicity, rhabdomyolysis or hyperkalaemia: loss of the patellar reflex is the earliest sign of magnesium toxicity; creatine kinase values in the thousands signal rhabdomyolysis with myoglobinuric kidney injury, and hyperkalaemia is doubly dangerous in an unstable myocardium.Not available at your setup — Serum electrolytes.
  • Do not treat a normal PaCO₂ as reassurance: a rising PaCO₂ in a sedated, fatiguing patient is an indication to intubate rather than observe, and a normal PaCO₂ in a tiring patient is already ominous.Not available at your setup — Arterial blood gas.
  • Do not order lumbar puncture or CT reflexively in a patient with unmistakable trismus and risus sardonicus — they are normal in tetanus and indicated only if meningitis or intracranial pathology cannot be excluded clinically, particularly where consciousness is impaired.Not available at your setup — CT scan.
  • Do not omit the wound that seems trivial: a small puncture wound sealing over an anaerobic tract is more dangerous than an open laceration, and its trivial appearance is a common reason for missed prophylaxis; passive protection with HTIG or HNIG is short-lived, lasting only about two weeks, so it buys time and does not immunise.

Refer / escalate

Call for help and arrange transfer to a facility with mechanical ventilation immediately for any spasm involving the jaw, larynx, neck or respiratory muscles, apnoeic or desaturating episodes, inability to swallow saliva, a rising respiratory rate or PaCO₂, exhaustion, an escalating benzodiazepine requirement, autonomic instability, Ablett grade II or above (grade III implies ventilation and grade IV prolonged ventilation with deep sedation), or any case of cephalic or neonatal tetanus.

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