21 محرم 1435 هـ Pediatric Lec.
27/12/2013
TETANUS
Definition :- Acute spastic paralytic disorder caused by bacterial neurotoxin of Clostridium tetani.
Aetiology :-
Cl. tetani is a motile gram +ve spore forming anaerobe found in soil, dust , and alimentary tract of animals.
Spores are resistant to boiling but not to autoclaving.
Pathogenesis :-
Spores germinate and bacilli multiply in anaerobic conditions in necrotic tissues if O2 tension by other aerobic bacteria is reduced.The localized vegetative organisms produce an exotoxin " Tetanus Toxin " transmitted by blood stream to motor neurone cells and nerve endings including anterior horn cells leading to muscular rigidity and convulsions.
Organisms get to the blood stream in the neonatal umbilicus enter the skin with nails ,splinters or unsterile injections ,animal bites burns, compound fractures, or circumcision.
Clinical features :-
I.P is usually 2-14 days ,occasionally months after injury.
*Generalized T. –starts with headache , restlessness ,irritability ,spasm of the masseters "Trismus" or Lockjaw and stiff neck.Spasm of facial muscles cause sardonic smile " Risus Sardonicus ".
Nuchal regidity
Paralysis extending to trunk and limb muscles lead to hyperextension of the body " opisthotonus ".
If it involves the laryngeal or respiratory muscle airways obstruction follows and asphyxia .Spasms are painful lasting for 3-4 minutes taking place spontaneously or after minimal stimuli.
Seizures (convulsions) may follow with clinching, abduction of arms and extension of legs increasing in severity in a weaks time ending in death as a result of exhaustion, asphyxia or aspiration pneumonia. Retension of urine and spontaneous defecation may occur .Fever unusual, hypertension may follow autonomic involvement.
*Neonatal T.-(Tetanus Neonatorum) within 3-12 days after birth starting with feeding difficulty and excessive crying together with stiffness and rigidity with spasm and possibly opisthotonus, mortality very high.
*Localized T. –painful muscle spasm adjacent to injury site.
*Cephalic T- after head injury or nasal f.b.
Diagnosis :- clinical ,organism can only be isolated in one third of cases .The lab. Results are usually normal exept if there is secondary infection resulting in leucocytosis
Differential Diagnosis :
Trismus may be due to dental abscess, rarely encephalitis.
Rabies – hydrophobia and clonic seizures.
Strychnine poisoning – no trismus generalized spasm with seizures and relaxation in between
Hypocalcemia-tetany, no trismus.
Phenothiazine over dosage, hysteria.
Complications :
aspiration pneumonia – careful feeding, possible tube.Skeletal injury- fracture or hge
Venous thrombosis, cardiac arrhythmia.
Treatment :-
Local – wound debritment.Antitoxin –tetanus immune globulin neutralize toxin not yet fixed in tissues 500-3000 i.u IM or IV. If not available animal tetanus antitoxin 50 000- 100 000 i.u IM or IV. hypersensitivity checked to avoid serum sickness, and anaphylactic shock.
Anti bacterials –Penicllin G 100 000 iu/kg/day four to six hourly IV for 10-14 days if allergic give metronidazole 500 mg IV 6 hourly for adults, or Erythromycin or Tetracycline over 9 yrs. of age , to eradicate vegetative
Spasm and seizure control Diazepam 0.1-0.2 mg / kg every 3-6 hrs.IV,the alternatives are Mgso4 or chlorpromazine
Endotracheal tube or trachiostomy in respiratory obstruction .
Patient nursed in quite room with attention to hydration and nutrition and secondary infection.
Prevention :-
Active immunization as DPT at 2 , 4 ,6 mo. ,booster at 4-6 yrs. and every 10 yrs. thereafter. Tetanus infection does not give permanent immunity
Mothers to receive 2 doses of toxoid.
Wounds to be managed by surgical care and TIG or antitetanic serum if not vaccinated.