Reviewed and revised 9 February 2014
OVERVIEW
potentially lethal condition characterised by muscular rigidity and spasms, caused by the tetanospasmin toxin produced by Clostridium tetani, that may lead to life-threatening respiratory failure and autonomic dysregulation in severe casesrare in the developed world, but accounts 1 million deaths worldwide each yearTYPES
cephaliclocalgeneralisedneonatal (50% of tetanus deaths worldwide)CAUSE
Clostridium tetani
caused by toxin from Clostridium tetani -> able to survive in the environment as highly resistant sporesanaerobic spore forming gram positive bacillusonce in a suitable environment -> spores germinate -> bacteria multiply -> toxins released (tetanospasmin and tetanolysin)Tetanospasmin
taken up by motor nerves or haematogenous spread to CNSdisrupts synaptic transmission by preventing release of neurotransmitters (zinc endopeptidase)preferentially prevents discharge from GABA inhibitory interneurons in spinal cord and brainstem-> unrestricted motor nerve activity and autonomic instabilityCLINICAL FEATURES
Clinical triad of rigidity, muscle spasms and, if severe, autonomic dysfunction
contaminated wound (may be trivial) or umbilical stump in neonatesincubation period: 3-14d (1-60 at the extremes) = time to first symptomonset time: 1-7d = time from first symptom to first spasmrigidity (persists > 2 weeks)— trismus, dysphagia, increased tone in trunk muscles – greater on side of injury initiallyspasms (reduce after 2 weeks)— spontaneous or provoked by physical or emotional stimuli, laryngospasm, risus sardonicus, opisthotonos (severe spasm in which the back arches and the head bends back and heels flex toward the back)autonomic disturbance (onset after spasms, lasts 1-2 weeks)— tachycardia and hypertension may alternate with bradycardia and hypotension, dysrhythmia, cardiac arrest— salivation, bronchial secretions— gastric stasis, ileus, diarrhoearespiratory compromise— chest wall rigidity— laryngospasm— aspiration— retained secretionsDIFFERENTIAL DIAGNOSIS
Diagnosis of tetanus is made clinically
strychnine poisoningtrismus due to orofacial infectionstiff person syndromeacute dystonic reactionseizure disorderhypocalcaemic tetanypsychogenicmeningismNeonatal tetanus may resemble:
SeizuresmeningitissepsisINVESTIGATIONS
urinary strychnine to exclude this as a causeCK, UEC, CMP for rhabdomyolysis and to rule out low CaABG (respiratory failure)MANAGEMENT
Resuscitation
A – intubate as requires large doses of sedatives to control muscle spasm and to overcome laryngospasmB – at risk of aspiration and have copious bronchial secretions requiring frequent suctioning, often ventilated for 2-3 weeks until spasms subsideC – autonomic dysfunction necessitate monitoring in a critical care environment, fluctuant haemodynamics so use short acting agents; fluid loadingD – benzodiazepines in large doses (up to 100mg/h diazepam) -> non-depolarsing NMBD
Specific Therapy
metronidazole (first choice); penicillin is used throughout most of the world but is a GABA antagonistanti-tetanus immunoglobulin: 100-300IU/kg of human Ig IMbenzodiazepines; adjuncts include barbiturates, propofol, chlorpromazineMg to 2-4mmol/L as useful in spasm treatment and limits autonomic instabilityconsider dantrolene (unproven)consider intrathecal baclofenTreat underlying cause and complications
clean and debride wounds (source control)immunize (infection does not confer immunity) – Q10 yearlySupportive care and monitoring – usual cares with emphasis on:
calm environmentcardiac monitoringnutrition e.g. enteral feedingoften require tracheostomyprevention of pressure sores and GI stress ulcersCOMPLICATIONS
Respiratory
AspirationLaryngospasm/obstructionSedative-associated obstructionRespiratory apnoeaType I (atelectasis, aspiration, pneumonia) and type II respiratory failure (laryngeal spasm, prolonged truncal spasm, excessive sedation)ARDSComplications of prolonged assisted ventilation (e.g. pneumonia)Tracheostomy complications (e.g. tracheal stenosis)Cardiovascular
Tachycardia, hypertension, ischaemiaHypotension, bradycardia, asystoleDysrhythmiasCardiac failureRenal
High output renal failureOliguric renal failureUrinary stasis and infectionGI
Gastric stasisIleusDiarrhoeaHaemorrhageOther
DehydrationWeight lossThromboembolusSepsis and multiple organ failureMusculoskeletal
Fractures of vertebrae during spasmsTendon avulsion during spasms rhabdomyolysisPROGNOSIS
Mortality
untreated: >50% (usually due to respiratory failure)high level ICU care available: 10-25% (usually due to autonomic failure)Survivors
severe cases usually require 3-5 weeks in ICUoften make full recoveryIndicators of poor prognosis
1. incubation of < 7 days2. period of onset < 48 hours3. portal of entry from umbilicus, uterus, burns, open fracture or IM injection4. presence of spasms5. temperature > 38.46. HR > 120 (adults), > 150 (neonates)
References and LinksLITFL
Clinical Case – Stiff in the mouthJournal
Cook TM, Protheroe RT, Handel JM. Tetanus: a review of the literature. Br J Anaesth. 2001 Sep;87(3):477-87. Review. PubMed PMID: 11517134.Dingli K, Morgan R, Leen C. Acute dystonic reaction caused by metoclopramide, versus tetanus. BMJ. 2007 Apr 28;334(7599):899-900. PMC1857743.Farrar JJ, Yen LM, Cook T, Fairweather N, Binh N, Parry J, Parry CM. Tetanus. J Neurol Neurosurg Psychiatry. 2000 Sep;69(3):292-301. Review. PubMed PMID: 10945801; PubMed Central PMCID: PMC1737078.Critical CareCompendium
…more CCC Chris NicksonChris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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