Tetanus

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

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