Acute tetanus

Background

1. C. tetani spores enter skin through wound, make tetanospasmin toxin
   1. Lacs, abrasions, puncture wounds
   2. Preferentially binds GABA and glycinergic neurons and blocks presynaptic release
      1. Motor neurons undergo sustained excitatory discharge
2. Spores found in soil and human feces
3. 2001-2008 in US, 233 cases, 26 deaths
4. Mortality as high as 45%
5. Incubation is 2 to 56d
6. If the pt survives, no residual sequealae

Types

Neonatal

1. from umbilical stump infection. Usually protected by passive maternal Abs
2. sx- poor suck, irritability, crying, grimacing
3. usually with in 10 d of birth

Local

1. rigidity of muscles near wound- may progress to generalized

Generalized

1. most common form
2. pts are conscious and alert
3. hypersympathetic state c sweating, HTN, tachycardia, fever

Cephalic

1. follow injuries to head or otitis media
2. get CN dysfunction- usually CN 7

Diagnosis

1. Progressive symptoms
   1. Alert and able to communicate
   2. Trismus - lockjaw (50%-75% of patients)
   3. Sardonic smile (risus sardonicus) - other facial muscles become involved
   4. Minor stimuli such as touch or noise start tetanic contractions
   5. Abd, back, diff swallowing
   6. Long bone fractures, tendon rupture
   7. Opisthotonus - contractures that resemble decorticate posturing
2. DX = clinical

Differential Diagnosis

• Dystonic reaction
• strychnine
• hypocalcemic tetany
• PTA
• teritonitis. SAN
• Meningitis
• Rabies
• TMJ

Jaw Spasms

• Acute tetanus
• Akathisia
• Conversion disorder
• Drug toxicity (anticholinergic, phenytoin, valproate, carbamazepine)
• Dystonic reaction
• Electrolyte abnormality
  • Hypocalcemic tetany
  • Magnesium
• Mandible dislocation
• Meningitis
• Peritonsillar abscess
• Rabies
• Seizure
• Strychnine poisoning
• Stroke
• Temporomandibular disorder
• Torticollis

Treatment

• wound debridement
• TIG- 3000- 10K IM- prevents additional dz but does not reverse toxin already fixed to CNS. Binds circulating toxin
• IVF/ hyperal
• quiet room
• sedation with phenobarb, valium or paralytics

Antibiotics

Metronidizole

• 500 mg IV every 6 hours

(<1200g)

• 7.5 mg/kg PO/IV q48h
• First Dose: 7.5 mg/kg PO/IV x 1

(>1200g AND <1 Month Old)

• <7 days old
  • 7.5-15 mg/kg/day PO/IV q12-24h
  • First Dose: 7.5-15 mg/kg PO/IV x 1
• >7 days old
  • 15-30 mg/kg/day PO/IV q12h
  • First Dose: 7.5-15 mg/kg PO/IV x 1

(>1 Month Old)

• 30 mg/kg/day PO/IV q6h
• First Dose: 7.5 mg/kg PO/IV x 1
• Max: 4 g/day

Penicillin

• Although once the drug of choice it is now no longer recommended since it may potentiate the effect of tetanus toxin by inhibiting the GABA receptors

See Also

• Tetanus (Prophylaxis)
• Clostridium