Multisystem Processes & Disorders

Tetanus: prophylaxis and management

Clinical Overview and When to Suspect Tetanus

— Unimmunized or undervaccinated adult (especially >65, immigrant from country without robust vaccination program) with trismus ("lockjaw"), neck stiffness, dysphagia, or generalized rigidity

— Puncture wound, burn, crush injury, frostbite, IV drug use ("skin popping"), or chronic ulcer in a patient with no booster in >5–10 years

— Neonate with poor feeding, rigidity, and spasms days after non-sterile umbilical cord care (neonatal tetanus — rare in US, common globally)

— Postpartum tetanus after unsterile delivery/abortion

— Generalized (~80%): descending pattern beginning with trismus, risus sardonicus, opisthotonos

— Local: persistent rigidity near wound

— Cephalic: cranial nerve palsies (often CN VII) after head/neck wound or otitis media

— Neonatal: highest mortality

Tetanus is a toxin-mediated neurologic disease caused by Clostridium tetani, a gram-positive, spore-forming, obligate anaerobe found ubiquitously in soil, dust, and animal feces

Pathogenesis: spores enter a wound → germinate in anaerobic tissue → release tetanospasmin → retrograde axonal transport to spinal cord/brainstem → blocks release of inhibitory neurotransmitters (GABA, glycine) from Renshaw cells → unopposed motor neuron firing → sustained muscle contraction and autonomic instability

Incubation: typically 3–21 days (median ~8); shorter incubation = worse prognosis

When to suspect in the ED or clinic:

Forms:

US epidemiology: ~30 cases/year, mortality 10–20%, highest in adults >65 and unvaccinated

Board pearl: Tetanus is a clinical diagnosis — wound cultures are positive in <30% and are neither sensitive nor specific. Do not delay treatment waiting for microbiology

Step 3 management: In any wound visit, the very first reflex is to ask: "When was your last Td/Tdap?" — prophylaxis decisions are tested far more often than active disease management

Presentation Patterns and Key History

— Day 1–2 of symptoms: trismus (masseter spasm) in ~75% — patient cannot open mouth, often misdiagnosed as dental abscess or TMJ

— Risus sardonicus: sustained grin from facial muscle spasm

— Neck stiffness, dysphagia, irritability

— Truncal rigidity → opisthotonos (arched back), boardlike abdomen mimicking surgical abdomen

— Reflex spasms triggered by light, sound, touch — extremely painful, patient remains fully conscious

— Autonomic storm (days 3–7): labile BP, tachy/bradyarrhythmias, diaphoresis, hyperthermia

— Vaccination history: primary series complete? Last booster date? Tdap ever received?

— Wound details: mechanism (puncture, crush, burn, frostbite, avulsion), contamination (soil, saliva, feces, rust), age of wound (>6 hours = higher risk), depth (>1 cm), devitalized tissue, retained foreign body

— IV drug use, especially heroin "skin popping" or contaminated black tar heroin

— Recent surgery, dental procedure, otitis media (cephalic tetanus), unsterile delivery

— Immunocompromise, diabetes (chronic foot ulcers are classic portal)

— Country of origin and immigration timing

Hallmark progression of generalized tetanus (descending pattern, unlike botulism which is descending paralysis without rigidity):

Key historical elements to elicit:

Key distinction: Trismus from tetanus vs dystonic reaction to antipsychotics/antiemetics — dystonia responds to diphenhydramine or benztropine within minutes; tetanus does not. Also distinguish from strychnine poisoning (similar spasms but no trismus initially, normal between spasms, history of rodenticide exposure)

Cephalic tetanus pearl: facial nerve palsy + history of head wound or chronic otitis → think tetanus, not Bell palsy

Board pearl: Mentation is preserved throughout tetanus — a rigid, spasming, alert, terrified patient is the classic stem. Loss of consciousness suggests an alternative diagnosis or hypoxic complication

Physical Exam Findings and Hemodynamic Assessment

— Trismus: inability to fully open mouth; assess with "spatula test" — touching posterior pharynx with tongue blade triggers reflex masseter bite (positive) rather than gag (negative). Reported sensitivity ~94%, specificity ~100%

— Risus sardonicus: raised eyebrows, drawn-back lips

— Cephalic form: CN VII palsy most common, also III, IV, VI, IX, X, XII

— Nuchal rigidity (mimics meningitis but no fever initially, no photophobia from meningeal irritation per se)

— Opisthotonos: hyperextension of spine during spasm

— Boardlike rigid abdomen → don't confuse with peritonitis

— Wide BP swings (160/100 → 80/40 within minutes)

— Tachycardia alternating with bradycardia/asystole

— Hyperpyrexia (39–40°C without infection)

— Profuse sweating, ileus, urinary retention

General appearance: anxious, diaphoretic, alert and oriented despite severe rigidity — this preserved sensorium is a signature finding

HEENT:

Neck/trunk:

Extremities: flexed arms, extended legs during spasms; between spasms, baseline hypertonia persists (unlike strychnine where tone normalizes)

Reflex spasms: provoked by minimal stimuli — flick of light, door slam, IV placement; can cause laryngospasm (airway emergency) and vertebral compression fractures

Autonomic hyperactivity exam:

Wound exam: often appears unimpressive — small puncture, healing laceration, or no identifiable wound in up to 20%. Inspect feet, scalp, ears, perineum, IV injection sites

CCS pearl: On the CCS case, order continuous cardiac monitoring, arterial line, and a quiet darkened room early — these are scored as appropriate supportive measures. Stimulation precipitates lethal spasms

Step 3 management: Hemodynamic lability is treated with labetalol or magnesium for sympathetic surges; avoid pure beta-blockade alone (unopposed alpha → paradoxical hypertension). Esmolol infusion is preferred for titratability

Diagnostic Workup — Initial Labs and Studies

— CBC: often normal; leukocytosis suggests superinfection

— CMP: monitor for rhabdomyolysis-related AKI, electrolyte derangements from autonomic storm

— CK: elevated from sustained muscle contraction; trend for rhabdomyolysis

— Lactate: elevated during severe spasms

— ABG: respiratory acidosis if ventilation compromised by chest wall rigidity or laryngospasm

— Coags, type & screen if intubation/procedures anticipated

— Blood cultures if febrile (rule out sepsis mimicking autonomic storm)

— Urine drug screen and strychnine level if suspected (rare, but classic mimic)

— Anti-tetanus antibody titer: protective level ≥0.1 IU/mL — if drawn before TIG administration and protective, tetanus is unlikely (high NPV). Send but do not wait for result

— Gram stain and anaerobic culture of wound (low yield, ~30%, but supports diagnosis if positive)

— Imaging (XR/CT) of wound site to find retained foreign body or gas

— Spatula test (see chunk 3) — high specificity

— Trial of diphenhydramine 50 mg IV: if rigidity resolves → dystonic reaction, not tetanus

Tetanus is a clinical diagnosis — no lab test confirms or excludes it. Workup serves to exclude mimics and assess complications

Initial labs on suspected case:

Wound studies:

ECG: continuous monitoring; watch for arrhythmias from autonomic dysregulation

CXR: baseline; aspiration pneumonia is a common complication

Bedside maneuvers:

Board pearl: A protective anti-tetanus IgG ≥0.1 IU/mL drawn at presentation essentially rules out tetanus and is the single most useful "negative" test. Many board stems hinge on the patient being unimmunized or last booster >10 years ago

Step 3 management: In the ED, prioritize airway readiness, IV access, dark/quiet room, and TIG/wound care over diagnostic workup — do not delay treatment for confirmatory testing

Diagnostic Workup — Advanced and Confirmatory Studies

— Strychnine level (sent to reference lab; treat empirically if suspected)

— Antipsychotic/antiemetic exposure history → consider dystonia

— Black widow spider antivenom trial if envenomation possible

— Panorex or CT face to rule out peritonsillar/retropharyngeal abscess, parapharyngeal infection, mandibular osteomyelitis causing trismus

— Acute onset of hypertonia and/or painful muscular contractions (usually masseter and neck) AND generalized muscle spasms without other apparent cause

— Tetanus is a nationally notifiable disease — report to local health department

— Botulism: descending flaccid paralysis, dilated pupils, no rigidity, no spasms

— Stiff person syndrome: chronic course, anti-GAD antibodies, responds to diazepam dramatically

— Neuroleptic malignant syndrome: dopamine antagonist exposure, altered mentation, lead-pipe rigidity, hyperthermia

— Serotonin syndrome: clonus, hyperreflexia, SSRI/MAOI use

— Hypocalcemia/tetany: Chvostek/Trousseau, low ionized Ca, no trismus

EMG: may show continuous motor unit activity with absent silent period after blink reflex — supportive but not required; reserved for atypical cases

Lumbar puncture: normal CSF in tetanus — perform only to exclude meningitis/encephalitis when diagnosis unclear (e.g., febrile patient with neck stiffness and altered mentation — which would itself argue against tetanus)

Neuroimaging (CT/MRI brain): normal in tetanus; obtain if stroke, intracranial hemorrhage, or structural cause of trismus suspected

Toxicology:

Dental/ENT eval:

Wound exploration in OR if deep puncture, devitalized tissue, or retained foreign body — debridement is therapeutic and diagnostic

Confirmatory criteria (CDC clinical case definition):

Key distinction:

Board pearl: When a stem describes spasms with preserved mentation, no fever initially, and a wound with poor vaccination history, the answer is tetanus regardless of culture results

Step 3 management: File public health report and notify infection control on admission — this is a scored step in CCS scenarios

Risk Stratification and First-Line Management Logic

1. Airway protection and respiratory support

2. Neutralize unbound toxin with human tetanus immune globulin (TIG)

3. Eliminate the source: wound debridement + antibiotics

4. Control spasms and autonomic instability

5. Active immunization (tetanus toxoid) — disease does not confer immunity

— Grade I (mild): mild trismus, no respiratory or swallowing compromise → admit, monitor

— Grade II (moderate): moderate trismus, dysphagia, brief spasms → ICU

— Grade III (severe): severe spasms, respiratory compromise, autonomic dysfunction → ICU with intubation

— Grade IV (very severe): grade III + severe autonomic storm → ICU, neuromuscular blockade, often tracheostomy

— Incubation <7 days, onset (first symptom to first spasm) <48 hours

— Age >60, neonatal form, IV drug use

— Entry through burn, surgery, or umbilical stump

— Autonomic instability, fever >40°C

— All suspected tetanus → ICU admission with quiet, dark room, minimal stimulation, clustered nursing care

— Early elective intubation/tracheostomy if dysphagia, laryngospasm risk, or grade III+

Once suspected, management proceeds simultaneously on five fronts (memorize these — frequent CCS order set):

Severity grading (Ablett classification) guides disposition:

Risk factors for poor prognosis:

Disposition:

CCS pearl: Order in the first 15 minutes — IV access ×2, cardiac monitor, pulse oximetry, human TIG 500 units IM (give before debridement), metronidazole 500 mg IV q6h, midazolam infusion, Tdap 0.5 mL IM in opposite limb from TIG, surgical consult for debridement, ICU bed

Step 3 management: TIG and toxoid must be given in different limbs with different syringes — co-administration in same site neutralizes the vaccine antigen. This is a frequently tested detail

Pharmacotherapy — First-Line Regimen

— Dose: 500 units IM (some references 3,000–6,000 units; 500 is now standard and equally effective)

— Neutralizes circulating, unbound toxin only — cannot reverse toxin already bound to nerve endings

— Give before wound debridement to neutralize toxin released during manipulation

— Consider intrathecal TIG (250 units) in severe cases — some evidence of benefit, not universally adopted

— If HTIG unavailable: equine antitoxin (risk of serum sickness, anaphylaxis) or IVIG

— Metronidazole 500 mg IV q6–8h × 7–10 days — first line (penicillin is a GABA antagonist and can worsen spasms — historically used but now second-line)

— Alternative: doxycycline, macrolide

— Benzodiazepines first line: diazepam 10–40 mg IV q1–4h titrated, or midazolam infusion 5–15 mg/h — enhance GABA-A receptor activity, opposing toxin

— Add propofol infusion for refractory spasms

— Magnesium sulfate infusion (target 2–4 mmol/L): reduces spasms and autonomic instability — monitor reflexes (loss of patellar reflex = toxicity, hold infusion)

— Baclofen (intrathecal in refractory cases): GABA-B agonist

— Neuromuscular blockade (vecuronium, cisatracurium) with mechanical ventilation if spasms uncontrolled — requires deep sedation

— Magnesium sulfate is first-line

— Labetalol or esmolol for hypertensive surges

— Avoid short-acting pure beta-blockers alone

— Clonidine, morphine adjuncts

— Tdap 0.5 mL IM at diagnosis, then second dose at 4–8 weeks, third at 6–12 months (disease does not immunize)

Human Tetanus Immune Globulin (HTIG / TIG):

Antibiotics (eliminate vegetative C. tetani):

Spasm control (cornerstone of supportive care):

Autonomic dysfunction:

Active immunization:

Board pearl: Metronidazole over penicillin is the modern answer — improved survival and avoids GABA antagonism

Prophylaxis After Wounds — The High-Yield Algorithm

— Clean and minor: linear, <6 hours old, <1 cm deep, no devitalized tissue, no contamination

— All other wounds ("dirty"): punctures, crush, burns, frostbite, avulsions, contaminated with soil/saliva/feces, devitalized tissue, >6 hours old, gunshot

— Unknown or <3 doses of primary series

— ≥3 doses with last booster timing

Clean minor wound:

— <3 doses or unknown: Tdap (or Td), no TIG

— ≥3 doses, last dose <10 yrs: nothing

— ≥3 doses, last dose ≥10 yrs: Tdap/Td, no TIG

All other wounds:

— <3 doses or unknown: Tdap + TIG 250 units IM

— ≥3 doses, last dose <5 yrs: nothing

— ≥3 doses, last dose ≥5 yrs: Tdap/Td, no TIG

— Adults who have never received Tdap → give Tdap (boosts pertussis immunity)

— Subsequent boosters can be Td or Tdap interchangeably (2020 ACIP update)

— Wound prophylaxis dose: 250 units IM

— Treatment dose: 500 units IM (some 3000–6000)

— HIV/severe immunocompromise: give TIG for any wound regardless of vaccination history (vaccine response unreliable)

This is the single most tested aspect of tetanus on Step 3. Memorize the table:

Step 1: Classify the wound:

Step 2: Determine vaccination status (doses of tetanus toxoid):

Step 3: Apply the matrix:

Tdap vs Td:

TIG specifics:

Wound care: irrigate, debride devitalized tissue, remove foreign bodies; do not close grossly contaminated wounds primarily

Step 3 management: A 55-year-old with a rusty nail puncture who "had shots as a kid" and no booster in 15 years → Tdap + TIG 250 units IM in separate limbs. This stem appears in some form on nearly every Step 3 exam

Board pearl: Pregnant women should receive Tdap between 27–36 weeks of every pregnancy regardless of prior vaccination — protects neonate from pertussis and tetanus

Special Populations — Elderly and Renal/Hepatic Impairment

— Account for >60% of US tetanus cases and deaths — waning immunity, fewer boosters, more chronic wounds (DM foot ulcers, pressure injuries)

— Seroprevalence of protective antibodies drops from ~80% at age 20 to ~30% at age 70

— USPSTF/ACIP: Td or Tdap booster every 10 years; one Tdap if never received

— Higher mortality (up to 50% in untreated elderly) — lower threshold for ICU and early intubation

— Polypharmacy: benzodiazepine sedation causes more delirium, falls, aspiration — use lowest effective dose, consider dexmedetomidine adjunct

— Magnesium dosing: reduce in CrCl <30, monitor levels and DTRs closely

— Metronidazole: no adjustment for renal dysfunction, but metabolites accumulate in ESRD — reduce dose to q12h in dialysis

— Magnesium: major dose reduction in CKD/AKI — magnesium is renally cleared; toxicity (areflexia, respiratory depression, cardiac arrest) is a real risk. Target serum Mg 2–4 mmol/L with frequent levels

— Benzodiazepines: midazolam active metabolites accumulate; lorazepam preferred in renal failure (no active metabolites, glucuronidated)

— TIG and toxoid: no renal dose adjustment

— Metronidazole: reduce dose by 50% in severe hepatic dysfunction (Child-Pugh C)

— Diazepam: long half-life prolonged in cirrhosis → use lorazepam or oxazepam (no oxidative metabolism)

— Propofol: lipid load and hypotension risk in cirrhosis

— Vaccine response unreliable → give TIG for any wound that is not clean-minor, regardless of vaccination history

— Complete primary series if needed

Elderly (>65 years):

Renal impairment:

Hepatic impairment:

Immunocompromised (HIV, chemotherapy, transplant, asplenia):

Step 3 management: Routine shingles/pneumococcal visit in older adults is a natural moment to update Td/Tdap — bundling vaccinations improves coverage and is value-based-care positive

Board pearl: The classic missed-tetanus stem is an elderly gardener or farmer with a foot puncture, last booster "in the Army" 40 years ago

Special Populations — Pregnancy and Pediatrics

— Tdap recommended every pregnancy between 27 and 36 weeks gestation (optimal 27–32) — transplacental antibody transfer protects neonate from pertussis and tetanus in first months of life

— Give regardless of prior Tdap or interval since last booster — annual Tdap if pregnancies are close together is appropriate

— TIG is safe in pregnancy (Category C, no fetal harm reported) — give for indicated wounds

— Maternal tetanus is rare in US but devastating — postpartum/post-abortion tetanus possible after unsterile procedures

— Almost eliminated in US; major global cause of neonatal mortality

— Presents days 3–14 of life with poor feeding, inability to suck, rigidity, spasms, opisthotonos

— Cause: unsterile umbilical cord care, contamination with cow dung or ash (traditional practices)

— Prevention: maternal immunization + clean delivery + clean cord care ("3 cleans")

— Treatment: TIG 500 units IM, metronidazole, supportive ICU care; mortality very high (>50%)

— DTaP: 2, 4, 6, 15–18 months, 4–6 years (5 doses)

— Tdap: 11–12 years (single adolescent booster)

— Td or Tdap: every 10 years thereafter

— Catch-up schedules for under-vaccinated children

Pregnancy:

Neonatal tetanus:

Pediatric vaccination schedule (CDC/ACIP):

Wound prophylaxis in pediatrics: same algorithm as adults, using age-appropriate vaccine (DTaP <7 years, Tdap ≥7 years)

Pediatric tetanus in US: almost exclusively in unvaccinated children of vaccine-refusing families — a vaccine-refusal stem

Key distinction: Postpartum dystonic reaction to antiemetics (e.g., metoclopramide for hyperemesis) vs cephalic tetanus — dystonia resolves with diphenhydramine 25–50 mg IV; obtain delivery history (clean facility vs home birth) for tetanus risk

Step 3 management: On an ambulatory peds visit, verify Tdap at the 11–12 year well-child check — this is a quality measure and frequently tested as a missed-opportunity scenario

Board pearl: Tdap every pregnancy, 27–36 weeks — even if Tdap was given last year

Complications and Adverse Outcomes

— Laryngospasm: sudden, life-threatening — can occur with minimal stimulation, leading to asphyxia

— Aspiration pneumonia from dysphagia and impaired airway protection

— Hypoventilation from chest wall and diaphragmatic spasm

— Prolonged mechanical ventilation → ventilator-associated pneumonia, tracheostomy complications

— ARDS in severe cases

— Labile hypertension and hypotension

— Tachyarrhythmias, bradyarrhythmias, sudden asystole — leading cause of death in modern ICUs

— Myocarditis (toxin-mediated), takotsubo cardiomyopathy

— Thromboembolism from immobility

— Vertebral compression fractures during opisthotonic spasms (classic — image the spine after severe spasms)

— Long bone fractures, tongue laceration, joint dislocations (shoulder, hip)

— Rhabdomyolysis → AKI; trend CK, maintain urine output, alkalinize urine if severe

— Tendon ruptures

— Hypoxic-ischemic brain injury from laryngospasm or arrest

— Critical illness polyneuropathy/myopathy from prolonged NMB

— Ileus, gastric stress ulceration → PPI prophylaxis

— Urinary retention from sphincter spasm → Foley catheter

— Pressure ulcers, DVT — DVT prophylaxis essential

— Nutritional: catabolic state, dysphagia → early NG/PEG feeding

— Nosocomial infections (CLABSI, CAUTI, VAP)

— Most survivors recover fully over weeks to months as toxin effects wear off (toxin binding is irreversible; recovery requires new nerve terminal sprouting)

— Some residual stiffness, contractures, psychological sequelae (PTSD from prolonged ICU)

Respiratory:

Cardiovascular/autonomic:

Musculoskeletal:

Neurologic:

Other:

Long-term sequelae:

CCS pearl: In a tetanus CCS case, DVT prophylaxis, stress ulcer prophylaxis, NG feeds, pressure ulcer prevention, and physical therapy consult are all scored items even though they're not "tetanus-specific" — Step 3 rewards comprehensive ICU care

Board pearl: Death in modern tetanus is most often from autonomic dysfunction and arrhythmia, not respiratory failure — this is why magnesium and continuous cardiac monitoring matter

When to Escalate Care — ICU, Consult, and Triage

— Trismus interfering with airway access → elective intubation before emergent need

— Generalized spasms, laryngospasm, or stridor → immediate intubation

— Dysphagia with aspiration risk

— Autonomic instability (BP swings >30 mmHg, HR variability, hyperthermia)

— Respiratory rate >30, SpO2 <92%, hypercapnia on ABG

— Need for neuromuscular blockade → mandates intubation, deep sedation, arterial line, continuous EEG consideration

— Infectious disease: confirm management, antibiotic choice, report to public health

— Surgery: wound debridement (general, ortho, plastics depending on site)

— Critical care: ICU management, ventilator strategy

— Anesthesia: airway, regional/neuraxial considerations

— Neurology (selected): rule out mimics

— Physical medicine & rehab: early — for prolonged recovery planning

— Public health department: mandatory reporting

— If facility lacks ICU capacity, neuromuscular blockade expertise, or tracheostomy capability → transfer to tertiary center after stabilization, intubation if needed, and TIG administration

— Use ground transport when possible; aeromedical noise/vibration can trigger spasms

All suspected tetanus warrants ICU admission from the outset, even in apparently mild cases — deterioration can be rapid and unpredictable

Specific escalation triggers:

Anesthesia/airway team: involve early — intubation is high-risk (spasm provocation, hemodynamic lability). Tracheostomy often performed early (within 24–48 hours) for anticipated prolonged ventilation and to reduce laryngeal stimulation

Consultations:

Transfer considerations:

Quiet, dark room with clustered care — minimize stimulation

Step 3 management: Do not "watch and wait" in a step-down or telemetry bed — the testable answer for suspected tetanus is ICU admission, full stop

CCS pearl: Order environmental modifications explicitly — "private room, dim lights, minimize noise, cluster nursing interventions" — these are recognized as appropriate orders and reflect Step 3's emphasis on systems thinking

Key Differentials — Same-Category (Neuromuscular/Toxin-Mediated)

— Rodenticide/illicit drug adulterant

— Generalized spasms, opisthotonos — but no trismus initially, and patient is relaxed between spasms (in tetanus, baseline rigidity persists)

— Onset within minutes of exposure, not days

— Treat: supportive, benzodiazepines, activated charcoal if early

— Same organism family (Clostridium) but descending flaccid paralysis, not rigidity

— Dilated, sluggish pupils; dry mouth; ptosis; diplopia

— Sources: home-canned foods (adults), honey (infants), wound (IVDU)

— Treatment: equine antitoxin (adult), BabyBIG (infant)

— Within hours of dopamine antagonist (haloperidol, metoclopramide, prochlorperazine)

— Torticollis, oculogyric crisis, trismus

— Reverses with diphenhydramine 50 mg IV or benztropine within minutes — diagnostic and therapeutic

— Antipsychotic exposure, lead-pipe rigidity, hyperthermia, altered mentation, elevated CK

— Treat: stop offending agent, dantrolene, bromocriptine, cooling

— SSRI/MAOI/triptan/tramadol, clonus (especially lower extremities), hyperreflexia, agitation, hyperthermia

— Treat: cyproheptadine, supportive

— Inhaled anesthetic or succinylcholine exposure, masseter rigidity, hypercapnia, hyperthermia, rhabdo

— Treat: dantrolene, stop trigger

— Chronic, anti-GAD or anti-amphiphysin antibodies, dramatic response to high-dose diazepam, often associated with DM or breast cancer

— Carpopedal spasm, Chvostek/Trousseau, low ionized Ca, normal mentation, treat with IV calcium

Strychnine poisoning:

Botulism:

Dystonic reaction (acute):

Neuroleptic malignant syndrome:

Serotonin syndrome:

Malignant hyperthermia:

Stiff person syndrome:

Hypocalcemic tetany:

Key distinction: The fastest discriminator is the diphenhydramine trial — tetanus does not budge; dystonia resolves

Board pearl: Strychnine and tetanus are the two true "tonic spasm" mimics — strychnine has no trismus and relaxed intervals

Key Differentials — Other-Category Causes

— Fever, headache, altered mental status, photophobia, positive Kernig/Brudzinski

— Tetanus preserves mentation; meningitis does not

— LP differentiates (tetanus has normal CSF)

— Thunderclap headache, meningismus, possible LOC

— Non-contrast head CT, LP for xanthochromia

— Animal bite (especially bat, dog in endemic area), incubation weeks to months

— Hydrophobia, aerophobia, hypersalivation, encephalitic or paralytic form

— Almost universally fatal once symptomatic — emphasize postexposure prophylaxis (rabies IG + vaccine series)

— Cause trismus from local inflammation

— Fever, asymmetric pharyngeal exam, drooling

— CT neck with contrast; ENT consult

— Chronic, mechanical, no systemic findings

— Diagnosis of exclusion; inconsistent exam, distractibility

— Alcohol/benzodiazepine withdrawal: tremor, autonomic instability, seizures, altered mentation — distinguish by history and response to benzodiazepines (which also treat tetanus — overlap can be confusing)

— Severe muscle cramping, abdominal rigidity mimicking peritonitis, hypertension

— Bite history (often unwitnessed), small puncture lesion

— Treat: opioids, benzodiazepines, antivenom in severe cases

— Fever, hemodynamic instability — but rigors are brief, not sustained

Meningitis/encephalitis:

Subarachnoid hemorrhage:

Rabies:

Peritonsillar/retropharyngeal abscess, dental abscess, mandibular osteomyelitis:

Temporomandibular joint dysfunction:

Hypocalcemia/hypomagnesemia: see chunk 13

Conversion disorder/psychogenic:

Drug withdrawal:

Black widow envenomation:

Sepsis with myoclonus or rigors:

Step 3 management: A patient with trismus and fever is more likely to have a deep neck space infection than tetanus — get a CT neck with contrast before assuming tetanus, especially if vaccination is current

Board pearl: Rabies and tetanus are both wound-related neurologic diseases — the key board distinction is that rabies has hydrophobia and altered mentation, while tetanus has trismus and preserved mentation

Secondary Prevention, Discharge, and Long-Term Plan

— Natural infection does not induce immunity (toxin amount is sub-immunogenic)

— Complete a full 3-dose primary series: Tdap at diagnosis, second Td/Tdap at 4–8 weeks, third Td/Tdap at 6–12 months

— Then Td or Tdap booster every 10 years lifelong

— Taper benzodiazepines slowly (often weeks-long) to avoid withdrawal

— PPI prophylaxis if still at GI bleed risk

— DVT prophylaxis through period of immobility

— Pain control: scheduled acetaminophen, gabapentin or pregabalin for neuropathic pain from prolonged spasms and critical illness neuropathy

— Stool softeners (opioid-related constipation common)

— Surgical wound assessment q2–3 days until healed

— Repeat debridement if necessary

— Early PT/OT in ICU and continued post-discharge

— Acute inpatient rehab or SNF for most patients — critical illness myopathy/neuropathy is common

— Speech therapy for dysphagia (often persistent weeks after extubation)

— Psychiatric follow-up: PTSD, anxiety, depression after prolonged ICU stay

— Adults: Td or Tdap every 10 years

— Adults who never received Tdap: substitute Tdap for one Td booster

— Pregnancy: Tdap each pregnancy, 27–36 weeks

— Wound-based prophylaxis at every acute care visit

— Verify and update vaccination at every primary care visit, especially in elderly

Active immunization after tetanus disease:

Discharge medications (post-tetanus survivor):

Wound care follow-up:

Rehabilitation:

Primary prevention for the population (the real board emphasis):

Step 3 management: At discharge, write for Tdap dose #2 at 4–8 weeks and dose #3 at 6–12 months in the after-visit summary and notify PCP — closing this immunization loop is a transition-of-care quality measure

Board pearl: "Surviving tetanus does not immunize" — this counterintuitive fact is tested as a discharge planning item

Follow-Up, Monitoring, and Counseling

— Continuous cardiac telemetry, arterial line, frequent neuro checks (depth of sedation, spasm frequency)

— Daily CK, BUN/Cr (rhabdomyolysis, AKI from magnesium)

— Daily Mg levels with infusion; check DTRs every shift

— ABG as ventilation status changes

— Daily wound assessment with surgical team

— Day 7–14 after discharge: PCP visit for medication reconciliation, wound check, vaccine plan reinforcement

— 4–8 weeks: second tetanus toxoid dose

— 3 months: rehab progress, return to function assessment

— 6–12 months: third tetanus toxoid dose; reassess for residual neurologic/musculoskeletal deficits

— 10 years: routine Td/Tdap booster

— Functional status (ADLs, gait, grip strength)

— Pulmonary function if prolonged ventilation

— Mental health screening (PHQ-9, GAD-7, PTSD checklist)

— Nutrition: weight recovery, dysphagia resolution

— Tetanus does not confer immunity → must complete vaccine series

— Importance of 10-year boosters and reporting wounds promptly

— Wound first aid: irrigate immediately, seek care for puncture/contaminated wounds

— Recovery timeline: full recovery possible but takes weeks to months

— Garden/outdoor safety: gloves, footwear; avoid tetanus-prone activities until immune

— Use EHR-based vaccine reminders

— Standing orders for nursing to administer Td/Tdap at appropriate intervals

— Combine with annual flu visit or Medicare wellness visit

Inpatient monitoring (while admitted):

Post-ICU follow-up cadence:

Outpatient parameters to track:

Patient/family counseling:

Population-level counseling at primary care visits:

CCS pearl: Schedule a 2-week post-discharge clinic appointment and document vaccine series plan — Step 3 frequently scores transitions-of-care follow-up specifically

Board pearl: Patients often confuse "tetanus shot" with rabies prophylaxis — explicitly counsel that they are different and tetanus boosters do not protect against rabies

Ethical, Legal, and Patient Safety Considerations

— Tetanus is a nationally notifiable disease — report each case to local/state health department within timeframe specified by jurisdiction (typically 24–72 hours)

— Reporting helps identify vaccine coverage gaps and outbreaks (rare)

— Adult patients with capacity may refuse Tdap and TIG after informed consent

— Document clearly: risks explained (death, prolonged ICU stay, permanent disability), patient understanding, decision

— For minors: parental refusal of routine childhood vaccines is permitted in most US states (with religious/philosophical exemptions varying by state), but refusal of post-exposure TIG/Tdap for a tetanus-prone wound in a child may trigger child protective services involvement under medical neglect statutes if life-threatening

— Engage ethics committee for contested cases

— Tetanus preserves mentation — capacity is usually intact unless heavily sedated

— Obtain consent for tracheostomy, debridement, neuromuscular blockade before initiation when possible

— Surrogate decision-maker if sedated/paralyzed

— Failure to complete vaccine series after acute episode is a common safety gap — use EHR reminders, warm handoff to PCP, written after-visit instructions

— Medication reconciliation at discharge: prolonged benzo taper schedule must be clearly documented to avoid abrupt cessation or overdose

— Verify last tetanus booster on every wound visit — failure to ask is a sentinel root cause in tetanus cases

— Standing order sets for wound prophylaxis reduce errors

— Double-check TIG and Tdap given in different limbs — co-administration at same site is a documented safety error

— Elderly, immigrants, IVDU, and uninsured patients have lowest vaccine coverage — leverage every encounter (ED visit, urgent care, dental) to update Td/Tdap

Mandatory reporting:

Vaccine refusal:

Informed consent in the spasming patient:

Transition of care risks:

Patient safety in the ED:

Public health/equity:

Step 3 management: In a vaccine-refusing parent whose child has a deep contaminated wound, engage social work and ethics, document conversation, give Tdap+TIG if needed under emergency exception doctrine for imminent life-threatening risk — this scenario tests medical neglect thresholds

High-Yield Associations and Rapid-Fire Facts

Clostridium tetani: gram-positive, spore-forming, obligate anaerobe; "tennis racket" appearance from terminal spore

Toxin: tetanospasmin (also called tetanus toxin) — second most lethal toxin known after botulinum

Mechanism: cleaves synaptobrevin (VAMP) — blocks release of GABA and glycine from inhibitory interneurons in spinal cord

Botulinum cleaves SNAP-25/syntaxin — blocks ACh release at NMJ

Incubation: 3–21 days; shorter = worse prognosis

"Period of onset" (first symptom to first generalized spasm) <48 h = severe disease

Trismus in ~75% of cases at presentation

Risus sardonicus, opisthotonos: classic exam findings

Spatula test: high sensitivity/specificity for tetanus

Mentation preserved — distinguishes from encephalitis, NMS, serotonin syndrome

Metronidazole is preferred over penicillin (penicillin is a GABA antagonist)

TIG: 250 units IM for wound prophylaxis; 500 units IM for treatment

TIG and toxoid in different limbs, different syringes

Tdap each pregnancy at 27–36 weeks

Routine adult Td/Tdap booster every 10 years; 5 years after a tetanus-prone wound

Magnesium sulfate for autonomic storm and spasms; watch for hyporeflexia

Benzodiazepines for spasm control — diazepam classic; midazolam infusion in ICU

Surviving tetanus does not immunize — complete 3-dose series

Mortality: 10–20% in modern US ICUs; >50% in elderly and neonatal forms

Cephalic tetanus = wound on head + cranial neuropathy (often CN VII)

Neonatal tetanus = unsterile umbilical cord care, global LMIC problem

IVDU (heroin "skin popping") is an emerging US risk factor

Diabetic foot ulcer is a classic portal in elderly

Tetanus is a clinical diagnosis — cultures positive in <30%

Anti-tetanus IgG ≥0.1 IU/mL = protective; useful negative predictor at presentation

Board pearl: If a Step 3 stem describes opisthotonos in a fully alert patient with a recent wound, the answer is tetanus — full stop

Board Question Stem Patterns

— Patient with laceration/puncture/burn; vaccine history given in detail

— Asked: which combination of Tdap, Td, or TIG?

— Trick details: "received DTaP as a child" (≥3 doses), "last booster 8 years ago" (clean = no shot needed, dirty = Td/Tdap only, no TIG), "immigrated, no records" (treat as <3 doses)

— Answer hinges on clean vs dirty wound and 5-year vs 10-year interval

— Elderly farmer/gardener/IVDU with trismus, opisthotonos, wound from days ago, no recent booster

— Asked: most likely diagnosis or next best step

— Answer: clinical diagnosis of tetanus → TIG + metronidazole + Tdap + ICU

— Trismus + recent metoclopramide → dystonic reaction (give diphenhydramine)

— Trismus + fever + asymmetric pharynx → peritonsillar/deep neck abscess (CT neck)

— Spasms with relaxation between, history of rodent control work → strychnine

— Descending paralysis, dilated pupils, home-canned food → botulism

— Pregnant woman at 30 weeks, last Tdap 2 years ago → still give Tdap this pregnancy

— Tetanus survivor at discharge → schedule 2nd dose at 4–8 weeks, 3rd at 6–12 months

— HIV/transplant patient with any non-clean-minor wound → give TIG regardless of vaccine history

— Tetanus patient on penicillin worsening → switch to metronidazole (penicillin is GABA antagonist)

— Tetanus patient with BP swings, tachycardia → magnesium sulfate infusion, labetalol for surges, avoid pure short-acting beta-blockade alone

— Order ICU, TIG, metronidazole, Tdap (different limb), benzodiazepine infusion, dark/quiet room, intubation if airway compromise, surgical debridement, public health report

Stem 1 — Wound prophylaxis algorithm (most common):

Stem 2 — Diagnosis of active tetanus:

Stem 3 — Differentiating mimics:

Stem 4 — Pregnancy:

Stem 5 — Vaccine series after disease:

Stem 6 — Immunocompromised patient with wound:

Stem 7 — Drug choice:

Stem 8 — Autonomic storm management:

Stem 9 — CCS scenario:

Step 3 management: Read the vaccine history and wound type sentences twice — these stems are dense with details where one word ("contaminated," "deep," "8 years") flips the answer

One-Line Recap

Tetanus is a clinically diagnosed, toxin-mediated neurologic emergency in under-immunized patients with contaminated wounds, treated with TIG + metronidazole + Tdap + benzodiazepines + ICU supportive care, while prevention via Td/Tdap boosters and wound-based prophylaxis is the most heavily tested Step 3 element.

Prophylaxis algorithm: clean-minor wound → Td/Tdap only if ≥10 yrs or <3 doses; all other wounds → Td/Tdap if ≥5 yrs or <3 doses, plus TIG 250 units IM if <3 doses or unknown; HIV/immunocompromised get TIG for any non-clean-minor wound regardless of history

Active disease bundle: ICU + TIG 500 units IM (neutralizes unbound toxin) + metronidazole (not penicillin — GABA antagonist) + Tdap in different limb (disease doesn't immunize) + benzodiazepines for spasms + magnesium for autonomic storm + early intubation/tracheostomy + dark quiet room + wound debridement + DVT/stress ulcer prophylaxis

Diagnosis is clinical: trismus + risus sardonicus + opisthotonos + preserved mentation + wound + under-vaccination; spatula test highly specific; cultures unhelpful

Special populations: Tdap every pregnancy 27–36 weeks; elderly account for >60% of US cases (waning immunity, foot ulcers); neonatal form from unsterile cord care; vaccine refusal in children with life-threatening wound triggers ethics/CPS consideration; complete 3-dose series after surviving disease (4–8 wks, 6–12 mo follow-up)

Board pearl: If you remember only one thing — ask about last tetanus booster at every wound visit, and give TIG and toxoid in separate limbs with separate syringes. These two reflexes will earn nearly every tetanus point on Step 3.