Tetanus and Rabies

Tetanus
Epidemiology of Tetanus
Definition
•    Tetanus (Greek ‘tetanus’ means ‘to contract’): A neurological disorder characterized by muscle rigidity caused by a toxin produced by tetanus bacilli (Clostridium tetani).

Epidemiology
•     Tetanus occurs sporadically all over Africa, Clostridium tetani is a ubiquitous organism present in the soil and in human and animal (cattle) faeces.
•     Normally, Tetanus bacilli live in the bowel of animals and humans.
•     When the bacilli are passed out in faeces, they form spores in order to survive the harsh
conditions outside.
•      Tetanus as a disease in humans occurs only when the spores enter the body through a contaminated wound.
•      Tetanus is an important disease because of its high case fatality rate of 20 – 40 percent in adults and 60 – 89% of the newborns even when the nursing care is excellent.
•       Tetanus is caused by toxin produced by clostridium tetani, a gram-positive rod which forms terminal spores giving it a characteristic ‘drum stick’ appearance under the microscope.
•      Tetanus bacillus is an obligate anaerobe i.e. can only live and multiply in the absence of oxygen.
•     Wounds which favour the growth of clostridium tetani:
o Umbilical stump in newborn (necrosis)
o Crush wounds (necrosis, poor blood supply)
o Stab wounds (deep)
o Wounds with foreign bodies
o Burns (necrosis, poor blood supply)
o Endometritis (after abortion or child birth, from the use of poorly sterilised
instruments)
o Surgical wounds (from dressing or instruments)
o Chronic ulcers (like jiggers or leprosy and chronic discharging ears)
•      Endogenous infection may occur when intestinal tetanus bacilli are introduced into the tissues e.g. during bowel surgery.
•      In 10-15% of tetanus cases, the site of entry remains undetected.
•     A special and very important form of tetanus is seen in the newborn.
•     This is called tetanus neonatorum and it is nearly always fatal, even with the best kind of treatment/management

•      The necrotic tissue in the umbilical stump is an ideal place for tetanus bacilli to enter the body, especially if cow’s dung containing tetanus bacilli is used for dressing the cord as it has been the custom in some communities in Africa.
•       The infection can also be introduced if unsterile instruments are used for cutting the umbilical cord.

Clinical Features of Tetanus
•    The incubation period is 5 – 21 days, but may range from 3 days to 3 months
•    Tetanus is characterised by muscular rigidity and spasms
•    Patient first notices increased tone in the jaw muscles, causing trismus or lockjaw and resus sardonicus (devil’s sign)
•     Later, the spasms becomes more generalized involving all muscles
•     Severe spasms are associated with pain and disturbances of swallowing and respiration
•     The spasms of the neck muscles resemble the neck stiffness of meningitis but other neurological signs supporting meningitis are negative
•      Death usually occurs due to asphyxia and exhaustion
•      Asphyxia may be due to:
o Spasm of glottis, thoracic muscles and diaphragm
o Chronic hypoventilation because of muscle stiffness
o Periods of apnoea
o Aspiration of food materials and respiratory secretions and subsequent suffocation
•      In the new born, the first sign of tetanus is inability to such by a baby who was doing well after delivery.
     Later on, spasms appear accompanied by severe apnoea and cyanosis.

Diagnosis and Management of Tetanus
Diagnosis
•   The diagnosis of tetanus is clinical, based on the history and examination finding.
         For an experienced clinician there is title difficult in making the diagnosis i.e. Painless spasm of the muscles of the jaw ‘Trismus’, difficulty in opening the mouth ‘lock Jaw’, contraction of the muscles on the forehead and mouth ‘risus sardonicus, and board-like rigidity of the abdomen.
•    There are no specific laboratory tests to determine the diagnosis of tetanus
•    Other tests may be used to rule out meningitis, rabies, chemical poisoning e.g. strychnine and other diseases with similar symptoms and signs

Management
•    Patients must be referred to hospital as quickly as possible where therapy should be instituted to:-
o Eliminate the source of toxin –Antibiotics
o Neutralize unbound toxin – Antitoxin e.g. ATS
o Prevent muscle spasm – use diazepam and other muscle relaxants
o Nursing support, wound care, airway support, feeding and sedation
•      Drugs used in a patient with tetanus include:
o Metronidaxole is the antibiotic of choice, although penicillin is still widely used.
o Patient treated with metronidazole have fewer spasms.
o Antibiotic combat secondary infection and the tetanus bacilli themselves.

o Antitoxin (Antitetanus Serum) - ATS, Adult and children are given 10,000 units IM
or IV once after a test dose first while keeping adrenaline at hand because allergic reactions are common and dangerous.
o Diazepam to prevent muscle spasm.
o Even at dispensary or health centre an attempt must be made to control the spasm by using diazepam before referring the patient.
o Start with 10 – 40mg intravenously and give the same dose at the same time in the form of crushed tablets through a nasogastric tube (NGT).
o Maintain sedation by giving the drugs every 3 hours through the tube.
o Further doses of diazepam should be given depending on the condition of the patient.
o Diazepam is usually very well tolerated and the maximum dose is very high (500mg daily).
o There is a need of making sure that heavily sedated patient’s airway is secured especially (this is done in hospitals – Intensive Care Unit).
o Chloralhydrate, phenobarbitone or chlorpromazine will sustain the effect of diazepam.
    Children are given chloralhydrate and adults phenobarbitone 100mg 4 hourly.
•        Nursing Support
o Wounds should be cleaned with spirit or disinfectant
o Tracheostomy with artificial respiration can only be performed in specialized centres
o Feeding of the patient via a nasogastric tube is important
o Respiratory support should be offered
o The patient should be kept in cool place also noise should be minimized
o Every patient must have an observation chart on which medication, fluid input, spasm
and position change are recorded
o Patients recovering from tetanus should be actively immunized against tetanus
because immunity is induced by the small amount of toxin that produces disease
Prevention and Control of Tetanus
•    Proper surgical treatment of wound, such as removal of foreign bodies and excision of necrotic tissue will diminish the risk of tetanus.
•     Active immunisation with tetanus toxoid gives adequate protection.
•     First 3 immunisations should be given in childhood, together with diphtheria, tetanus pertussis and hepatitis B (DPT-HB).
•      Tetanus of the newborn can be prevented by active immunisation of the mother during pregnancy.
•      It is recommended for adults to be vaccinated every 10 years to prevent tetanus.
•       Advising the community about hospital delivery will reduce the chance of acquiring infection.

Definition, Causes and Transmission of Rabies
Definition
•    Rabies: An acute viral disease that can affect all mammals (a zoonosis) and is
incidentally transmitted to human being by bite of a rabid animal.

Causes and Transmission
•      Rabies is caused by rabies virus, a rhabdovirus of the genus Lyssavirus.
•       The virus has preference for the salivary gland and nervous tissue, finally causing encephalitis and resulting in death.

•     The risk of rabies is present in all mainland African countries.
•     The main animal reservoirs of the disease are wild animal such as jackals, mangooses and hyaenas.
•      These animals usually do not live in close contact with humans, but they may infect domestic animals such as dogs and cats.
•       Cattle, horses and donkeys may also become infected.
•        Man becomes infected when bitten by a rabid animal, usually a dog.
•         Saliva left behind in the wound contains the virus which finds its way to the brain via the nerves.
•         When no immediate action is taken after a bite by an infectious animal, the disease is invariably fatal once the clinical signs have appeared (case fatality rate is 100%).
•       Africa has a large reservoir of diseased wild animals and the transmission between them and domestic animals is difficult to control under present conditions.

Clinical Features of Rabies
•    In human, the incubation period ranges from 2 weeks to 1 year, with an average of 2 -3 months depending on:
o Size of the bite
o Distance of wound from the brain
o Type of wound (abrasion, small wound, wound with extensive tissue damage)
o Dose of virus deposited in the wound.
•       The earliest symptoms usually consist of increasing severe pain in the wound.
•      Later, two different clinical pictures emerge i.e. furious and paralytic rabies.
•       The first, experienced by about 80% of patients is furious rabies.
•       This form of disease is characterized by periods of:
o Extreme anxiety
o Violet behaviour
o Seizures
o Hallucinations
•       This may then lead to paralytic rabies which manifests with:
o Depression
o Paralysis of the limbs
o Spasms of the pharyngeal muscles
o Hypersalivation
o Sweating
•         This result in intense hydrophobia (fear of water) because of the severe pain experienced when swallowing water.
•         They may have a tightly feeling in the throat and jerky spasms of the stenomastoids, diaphragm and other inspiratory muscles leading to a generalized extension, sometimes
with convulsions and episthotonus.
•         Coma eventually ensues, with flaccid paralysis.
•         Survival for more than a week is unlikely and death usually follows.
•         In animal, abnormal behaviour is one of the earliest things.
•         The animal may bite at the slightest provocation or without any provocation at all.
•         Animals may also be depressed and curl up in a corner.
•          Death usually ensues within 10 days of the onset of the disease.

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