Etiology:-
Tetanus, also called lockjaw
Acute,
Spastic paralysis caused by tetanus toxin,
Clostridium tetani, a motile, gram-positive, spore-forming obligate anaerobe
Natural habitat - soil, dust, and the alimentary tracts of animals
Spores are at the end of bacillus, producing a drumstick appearance
Tetanus spores can survive boiling but not autoclaving,
Vegetative bacilli are killed by antibiotics, heat, and disinfectants
Not a tissue-invasive organism
it causes illness through the toxin, tetanospasmin = second most poisonous substance known first being
Botulinum toxin
Epidemiology:-
Endemic in developing countries
Neonatal (umbilical) tetanus kills approximately 500,000 infants each year because the mother was not
immunized;
Unimmunized women of maternal tetanus that results from postpartum, postabortal, or post surgical wound
infection
Majority of childhood cases of tetanus occur in unimmunized children whose parents objected to vaccination.
Injury, penetrating wound by a dirty object, such as a nail, splinter, fragment of glass, or unsterile
injection, illicit drug injection , animal bites, abscesses (including dental abscesses), ear piercing, chronic skin
ulceration, burns, compound fractures, gangrene, intestinal surgery, infected insect bites, and circumcision.
use of contaminated suture material or intramuscular injection
Pathogenesis:-
Spores germinate, and produce tetanus toxin in low-oxygen-infected-injury site.
The toxin is released after bacterial cell death and lysis .
Tetanus toxin binds at the neuromuscular junction and enters the motor nerve
It travels up through axon of spinal motor neuron.
Then enters spinal inhibitory interneuron,
It prevents release of the neurotransmitter a-amino butyric acid (GABA).
Tetanus toxin blocks the normal inhibition of antagonistic muscles,
Affected muscles contract unopposed.
The autonomic nervous system is also affected in tetanus.
Clinical Manifestations:-
Generalized, or localized.
The incubation period is 2 - 14 days, may be months after injury.
In generalized tetanus, trismus (masseter muscle spasm or lockjaw) is the presenting symptom
Headache, restlessness, followed by stiffness, dysphagia, and neck muscle spasm.
The sardonic smile of tetanus (risus sardonicus) results from spasm of facial and buccal muscles.
Arched posture of hyperextension of the body, opisthotonos, with trunk bent backward
Board like rigidity of abdominal muscles
Laryngeal and respiratory muscle spasm can lead to airway obstruction and asphyxiation.
Tetanus toxin does not affect sensory nerves or cortical function
The patient remains conscious, can experience pain
Tetanic seizure- characterized by sudden, tonic contractions of the muscles,
fist clenching,
flexion, and adduction of the arms
Hyperextension of the legs
Lasts a few seconds to a few minutes
Sound or touch may trigger a spasm.
Becomes severe in the 1st wk, stabilizes in the 2nd wk, and decreases over 1 - 4 wk.
Dysuria and urinary retention result from bladder sphincter spasm
Fever - temperature as high as 40 C, is common because of heat produced by spastic muscles.
Autonomic effects = tachycardia, arrhythmias, labile hypertension, sweating
Neonatal tetanus (tetanus neonatorum):-
Infantile form of generalized tetanus
Manifests within 3—12 days of birth
Difficulty in feeding (i.e., sucking and swallowing)
Crying due to hunger
Stiffness to touch
Opisthotonos may occur
Umbilical stump may have dirt, dung, dotted blood, or serum, or it may appear clean.
Localized tetanus
Painful spasms of the muscles adjacent to the wound site
May precede generalized tetanus
Cephalic tetanus
Localized tetanus involving the bulbar musculature
Due to wounds or foreign bodies in the head, nostrils, or face
It also occurs in CSOM
Cephalic tetanus
Retracted eyelids
Deviated gaze
Trismus
Risus sardonicus
Spastic paralysis of tongue and pharynx
Diagnosis:-
Diagnosis clinically
Sensorium is clear
Laboratory studies arc normal.
A peripheral leucocytosis may result from a secondary bacterial infection
Cerebrospinal fluid (CSF) is normal
EEG and EMG are not specific
C. tetani is not always visible on Grain stain of wound material,
DIFFERENTIAL DIAGNOSIS:-
1) Trismus can occur from Para pharyngeal, retropharyngeal, or dental abscesses, or rarely, from acute
encephalitis involving brain stem
2) Rabies or tetanus may follow an animal bite
and CSF pleocytosis.
Rabies may he diagnosed hydrophobia, dysphagia,
3) Strychnine poisoning may result in muscle spasms. relaxation usually occurs between spasms.
There is no trismus
4) Hypocalcaemia - produce tetany, laryngeal and carpopedal spasms, No trismus
5) Stopping of anti epileptic drugs, narcotic withdrawal, may resemble tetanus
.
Treatment.
1) Eradication of C. tetani from wound
2) Neutralization of tetanus toxin
3) Control of seizures and respiration
4) Supportive care
5) Prevention of recurrence
Wound excision and debridement = remove foreign body or devitalized tissue
Administration of tetanus immunoglobulin (TIG)
IM dose of 500 U of TIG - but total doses as high as 3,000—6.000 U also recommended.
Infiltration of TIG into wound is considered unnecessary.
Intrathecal TIG, is given in our hospital 250 units.
Role of Antibiotics
Penicillin G (1 lakh U/kg/24 hr divided q 4—6 hr IV for 10—14 days) remains the antibiotic of choice
Metronidazole appears to be effective.
Erythrornycin and tetracycline - for patients 8 yr old or older) are alternatives for penicillin-allergic
patients.
muscle relaxants
Diazepam produces relaxation and seizure control
Initial dose of 0.1—0.2/kg every 2-4hr given intravenously is then titrated to control tetanic spasms,
continue for 2—6 wk before tapered withdrawal.
Magnesium sulphate,
benzodiazepines (e.g., midazolam)
chlorpromazine,
dantrolene,
baclofen are also used.
baclofen should be used only in an intensive care unit setting.
neuromuscular blocking agents = vecuronium and panctironiurn, = produce a general flaccid paralysis that
is then managed by mechanical ventilanon.
morphine also useful.
Supportive care
Quiet, dark, room is desirable.
Protect from unnecessary sounds, sights, and touch
Endotracheal intubation may not be required, may be done to prevent aspiration of secretions
Suctioning provokes reflex seizures and spasms
Cardio-respiratory monitoring
Maintenance of the fluid, electrolyte, and caloric needs
Nursing: - Cleaning of mouth, skin, bladder, and bowel needed to avoid ulceration, infection, and
constipation.
Complications:-
1. Aspiration of secretions and pneumonia
2. Endotracheal intubation and mechanical ventilation = pneumothorax and mediastinal emphysema.
3. Seizures result in
-
lacerations of the mouth or tongue,
Intramuscular hematoma
Rhabdomyolysis = myoglobinuria and renal failure.
Long bone or spinal fractures
4. Venous thrombosis
5. Pulmonary embolism
6. Gastric ulcer
7. Decubitus ulcer
8. Excessive use of muscle relaxants- produces iatrogenic apnea.
9. Cardiac arrhythmia
10. Labile temperature = hypothermia or fever
Prognosis:-
Recovery occurs by regeneration of synapses within the spinal cord
Tetanus disease does not produce toxin — neutralizing antibodies so,
Active immunization with tetanus toxoid at discharge is mandatory.
Favorable prognosis is associated with
-
long incubation period
absence of fever
Localized disease
Unfavorable prognosis
a week or less between the injury and the onset of trismus
with 3 days or less between trismus and the onset of generalized spasms.
Sequelae of hypoxic brain injury, in infants,
-
cerebral palsy,
diminished mental abilities
Behavioral difficulties
Death occurs in the 1 st wk of illness.
Prevention:-
Tetanus is a preventable disease
Active immunization - begin in early infancy with D P T at 2, 4 and 6 mo of age, with a booster at 4—6 yr of
age and at 10-yr intervals thereafter into adult life
Immunization of women with tetanus toxoid prevents neonatal tetanus
WOUND MANAGEMENT.
T T is given after a dog or any animal bite
All non-minor wounds require human T I G except in a fully immunized patient.
In circumstances (e.g., patients with an unknown or incomplete immunization history; crush, puncture,
wounds; wounds contaminated with saliva, Soil, or feces; - 250 U of T I G should be given intramuscularly,
and 500 U should be given for highly tetanus-prone wounds
Thorough surgical cleansing and debridement to remove foreign bodies, necrotic tissue
Tetanus toxoid should be given to stimulate active immunity and may be given with T I G
Tetanus toxoid booster - all persons with any wound if their immunization status is unknown
Source:DR.NS.MANI.MD Associate Professor in Pediatrics
