Tetanus

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Introduction

Tetanus is an infection caused by a bacterium called Clostridium tetani. It affects the nerves and causes painful muscle spasms and can lead to death.

It is a common, infectious disease affecting individuals of all ages and sexes, particularly the socio-economically deprived.

A neurologic disorder characterized by
increased muscle tone and spasm that is
caused by tetanospasmin, a powerful protein toxin elaborated by Clostridium tetani.

The bacterium is found in the soil, inanimate environment, animal faeces and occasionally in human faeces.
Its portals of entry include the following:

  • Umbilical stump
  • Female genital mutilation (FGM)
  • Male circumcision
  • Abortion sites
  • Penetrative wounds (e.g. nail puncture or intramuscular injection)
  • Head injury; scalp wounds
  • Traditional scarification (e.g. for tribal identity)
  • Trado-medical incisions
  • Post operative surgical sites
  • Chronic otitis media

Clinical forms:

  • Generalized tetanus
  • Neonatal tetanus
  • Localized tetanus
  • Cephalic tetanus

Clinical features

Generalized tetanus

  • Lock jaw
  • Dysphagia
  • Stiffness or pain in the neck, shoulder and back muscles
  • Rigid abdomen and stiff proximal limb muscles
  • The hands and feet are relatively spared

Neonatal tetanus

  • Poor feeding
  • Rigidity
  • Spasms

Localized tetanus.

  • Increased tone; spasms are restricted to the muscles near the wound
  • Prognosis is excellent

Cephalic tetanus

  • This follows head injury or ear infection
  • Trismus.
  • Dysfunction of one or more cranial nerves,often the 7* nerve
  • Mortality is high

Diagnosis

  • Tetanus diagnosis is entirely clinical

Differential diagnoses

  • Alveolar abscess
  • Strychnine poisoning
  • Dystonic drug reactions
  • Hypocalcaemic tetani
  • Meningitis/encephalitis
  • Acute abdomen

Complications

  • Autonomic dysfunction
    • Labile or sustained hypertension
    • Tachycardia
    • Dysarrhythmias
    • Hyperpyrexia
    • Profuse sweating
    • Peripheral vasoconstriction
    • Cardiac arrest
    • Aspiration pneumonia.
    • Fractures
  • Muscle rupture
  • Deep vein thrombophlebitis
  • Pulmonary emboli
  • Decubitus ulcers
  • Rhabdomyolysis

Investigations

  • Wound swab for microscopy, culture and sensitivity
  • Cerebrospinal fluid for biochemistry; microscopy, culture and sensitivity most
  • Full Blood Count; ESR
  • Urinalysis; urine microscopy, culture and sensitivity
  • Blood glucose
  • Electrocardiography
  • Serum Electrolytes, Urea and Creatinine
  • Electromyography

Treatment objectives

  • Eliminate the source of toxin airborne
  • Neutralize unbound toxin
  • Prevent muscle spasms
  • Monitor the patient’s condition and provide support (especially respiratory support) until recovery

Non-drug treatment

  • Admit patient to a quiet room
  • Protect airway
  • Explore wounds
  • Cleanse and thoroughly debride the wound
  • Provide intubation or tracheostomy for hypoventilation
  • Physiotherapy
  • Monitor bowel, bladder and renal function
  • Prevent decubitus ulcers

Drug treatment

Antibiotics

Benzylpenicillin (Penicillin G)

Adult:

  • 0.6 – 2.4 g daily by slow intravenous injection or infusion in 2-4 divided doses; thigher doses in severe infections

Child:

  • 1 month – 18 years, 100 mg/kg in 4 divided doses, every 6 hours; dose doubled in
    severe infections (maximum 2.4 g ,every 4 hours)
  • 1-4 weeks: 75 mg/kg daily in 3 divided doses, every 8 hours; dose doubled in severe infection
  • Preterm neonate and neonate under 7 days: 25 mg/kg every 12 hours; dose doubled in severe infection

Or:

Metronidazole

Adult:

  • 500 mg intravenously every 6 hours for 10 days

Child:

  • neonate, initially 15 mg/kg by
    intravenous infusion then 7.5 mg/kg twice daily;
  • 1 month- 12 years: 7.5 mg/kg
    (maximum 400 mg) every 8 hours;
  • 12 – 18 years: 400 mg every 8 hours

Antitoxin

Human tetanus immune globulin (TIG)

Adult:

  • 250 units by intramuscular injection, increased to 500 units if:
    • The wound is older than 12 hours
    • There is risk of heavy contamination
    • Patient weighs more than 90 kg
  • A second dose of 250 units should be given after 3 – 4 weeks if patient is immunosuppressed or if activeimmunization with tetanus vaccine is contraindicated
  • Administer antitoxin before manipulating the wound

Control of muscle spasm

Diazepam

Adult:

  • 20 mg intravenously slowly stat and titrate up to 250 mg/day in infusion

Child:

  • 1 month – 18 years: 100 – 300 micrograms/kg repeated every 1-4 hours by slow intravenous injection.

Could also be administered by intravenous infusion or by nasoduodenal tube as follows:

  • 3 10 mg/kg over 24 hours, adjusted according to response

Or:

Phenobarbital (dilute injection, 1 in 10 with water for injection)

Adult:

  • 10 mg/kg intravenously at a rate of not more than 100 mg/minute, up to maximum total dose of 1g

Child:

  • 5-10 mg/kg at a rate not more than 30mg/minute

Treat autonomic dysfunction with

  • Vasopressors, chronotropic agents if necessary

Hydration

  • To control insensitive and other fluid losses

Enteral or parenteral nutrition

  • As determined by clinical situation

Treat intercurrent infections

Notable adverse drug reactions, caution and contraindications

  • Diazepam is adsorbed from plastics of iinfusion bags and giving sets; causes, drowsiness and light headedness; hypotension
  • Benzyl penicillin: hypersensitivity reactions
  • Metronidazole: taste disturbances
  • Phenobarbital: caution in renal and hepatic impairment. May cause paradoxical excitement, restlessness and confusion in the elderly; hyperkinesia in children

Prevention

  • Active immunization of all partially or unimmunized adults, those recovering from tetanus, all pregnant women, infants and unimmunized (missed) children
  • Health education.
  • Improvement in socio-economic status

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