Tetanus

The airway is the emergency - Trismus from sustained masseter spasm, dysphagia, nuchal rigidity, risus sardonicus, and opisthotonus. Airway compromise progresses from dyspnea to obstruction and apnea, and laryngospasm is a documented complication. This patient meets the 2022 ASA difficult airway criteria for an awake approach on more than one count: difficult intubation is likely, aspiration risk is elevated, and they will not tolerate a brief apneic period. That guideline also asks you to have a strategy settled in advance for the cannot-intubate, cannot-ventilate case and to prepare for emergency invasive access, meaning front-of-neck cricothyrotomy or tracheostomy. The complication specific to tetanus is that awake instrumentation is itself a spasm trigger, which is why many of these airways are secured as a planned tracheostomy with the surgeon scrubbed rather than by laryngoscopy.

Tracheostomy is preferred over a translaryngeal tube - The endotracheal tube itself is a stimulus for muscle spasms, so tracheostomy is the preferred airway in established tetanus and is indicated outright whenever intubation will be needed beyond about ten days. Raise it early rather than after the third spasm around the tube.

Minimize stimulation - Reflex spasms are triggered by trivial stimuli: noise, touch, or light. Darken and quiet the room, cluster your interventions, and deepen sedation before you move, suction, or position the patient. Avoiding triggers is genuine therapy here, not a courtesy.

Benzodiazepines are the backbone - Diazepam is the most studied and most used, given IV at 10 to 40 mg every 1 to 8 hours to suppress spasms lasting more than 5 to 10 seconds, or midazolam by continuous infusion at 5 to 15 mg per hour. Doses are far above what you would use for routine sedation, and abruptly reducing them to transport the patient to the OR is how a spasm gets precipitated.

Neuromuscular blockade when sedation is not enough - Vecuronium and pancuronium are both used to control spasms, as is propofol, and baclofen including by the intrathecal route. Any of these commits the patient to controlled ventilation, so have the ventilator and the plan for it settled before you paralyze.

Magnesium - IV magnesium prevents spasms and is combined with a benzodiazepine for autonomic complications, given as a 5 g bolus followed by 2 to 3 g per hour until spasms are controlled. Monitor the patellar reflex throughout; areflexia means the level is too high and the dose comes down. With magnesium running, dose any relaxant to a quantitative train-of-four at the adductor pollicis rather than to weight. The 2023 ASA guideline makes quantitative monitoring, not a nerve stimulator read by feel, the standard, and sets a train-of-four ratio of at least 0.9 before extubation is even on the table.

Autonomic storm is what kills - Sympathetic overactivity is the leading cause of death in critically ill tetanus patients, appearing around the second week. Hypertension and tachycardia alternate with hypotension and bradycardia, plus diaphoresis, hyperpyrexia or hypothermia, dysrhythmias, and transient cardiac arrest. Put in an arterial line, because access to invasive blood pressure monitoring is one of the things that moves mortality, and use short-acting agents you can titrate in both directions. Have atropine and a pacing plan for the bradyarrhythmias.

Drugs for the sympathetic surges - Small doses of esmolol under strict monitoring, and morphine for pain and autonomic symptoms with the caveat that it drops the pressure. Magnesium plus benzodiazepine remains the first line for the autonomic component.

Full stomach and aspiration - Dysphagia, drooling, and pharyngeal spasm mean secretions the patient cannot clear. Aspiration pneumonia is a leading complication. Plan for RSI with suction ready, and expect copious secretions throughout.

Rhabdomyolysis - Sustained whole-body muscle contraction causes rhabdomyolysis and acute renal failure. Check a CK, potassium, and creatinine and follow the urine output. Think hard before succinylcholine in a patient who has been rigid and immobilized for days with a rising CK.

Plan for a long ventilatory course - Spasms can persist up to four weeks and full recovery takes months. Severe disease means ICU sedation and mechanical ventilation, and mortality tracks with the availability of ventilation, invasive monitoring, and early treatment. Do not plan on extubating at the end of the case; plan the handoff.

Treatment running alongside your anesthetic - Human tetanus immunoglobulin neutralizes circulating toxin but does nothing about toxin already bound in the CNS, which is why the course is long. Wound debridement is often the reason the patient is in your room. Metronidazole is the antibiotic of choice; penicillin is no longer recommended because of possible synergy with tetanospasmin. Infection confers no immunity, so the patient still needs the toxoid.

Tetanus is caused by Clostridium tetani, a spore-forming obligate anaerobe that is ubiquitous in the environment and germinates in the anaerobic conditions of a wound. It produces the neurotoxin tetanospasmin, which is taken up at motor nerve terminals, carried retrograde up the axon, and destroys a vesicular synaptic membrane protein, inactivating the glycine and GABA inhibitory neurotransmission that normally restrains motor and autonomic neurons. Loss of inhibition at the anterior horn cell produces rigidity and painful reflex spasms; loss of inhibition of autonomic neurons produces widespread autonomic instability once the toxin reaches the brainstem, typically in the second week. Generalized tetanus accounts for about 80% of cases. Recovery requires the growth of new nerve terminals, so the course runs weeks to months.