Tetanus

Question 1

Define Tetanus, probable tetanus by CDC

Answer 1

It is an acute disease manifested by skeletal muscle spasm and autonomic nervous system disturbance.
The CDC defines probable tetanus as an acute illness with muscle spasms or hypertonia in the absence of a more likely diagnosis.

Question 2

Define neonatal tetanus

Answer 2

Neonatal tetanus is defined by WHO as an illness occurring in a child who has the normal ability to suck and cry in the first 2 days of life but who loses this ability between 3 and 28 days of life and becomes rigid and has spasms.

Question 3

Define maternal tetanus

Answer 3

Maternal tetanus is defined by WHO as tetanus occurring during pregnancy or within 6 weeks after conclusion of pregnancy (whether with birth, miscarriage and abortion.

Question 4

What is the epidemiology of tetanus

Answer 4

Tetanus is a rare disease in the developed world.
In a 14 year prospective study carried out in a tertiary health facility in Northwest Nigeria, they found a prevalence of 6.5 cases per year with a complication rate of 71.4% and a mortality rate was 48.4%.
Globally, 7% of neonatal deaths was as a result of tetanus, but the incidence is up to 20% in Nigeria.
Almost always affects the non-immunized

Common in
areas where soil is cultivated
rural areas
warm climate
during summer months
among males

Question 5

What is the aetiology of tetanus?
Causative agent, characteristics of organism, sources and sources of neonatal

Answer 5

• Causative organism is Clostridium tetani.

*Poorly motile, spore-forming, anaerobic obligate, non encapsulated gram-positive bacillus

• Sources: soil, human and animal feces, house dust, clothing, air, slums, marine and freshwater sediments.
• Neonatal tetanus, source of infection is following infection of umbilical stump,
• open dirty wound, otitis media and circumcision or ear piercing

Question 6

What are the Risk Factors?

Answer 6

1. Acute injury (puncture wound, laceration, abrasion, etc, may be major or trivial
2. No identifiable injury or portal in some cases (20-30%)
3. Chronic conditions: skin ulcers, abscesses, and gangrene
4. Burns, frostbite, middle-ear infection, surgery, abortion, childbirth, body piercing, “skin popping

Question 7

Discuss clostridium, what exotoxins does it release
What is the minimal lethal dose of tetanospamin?

Answer 7

Clostridium produces two exotoxins: Tetanolysin and tetanospasmin.

1. Tetanolysin: increases tissue necrosis and optimises condition for multiplication of bacteria.
2. Tetanospasmin: implicated in tetanus.
   Very low concentrations of this highly potent toxin can result in tetanus (minimal lethal human dose is 2.5ng/kg).

Question 7

What is the pathogenesis of tetanus?

Answer 7

Spores may remain dormant for years
Spores become vegetative form in wounds under anaerobic conditions
Spores are resistant to heat, desiccation and disinfectants.

Question 8

Discuss Tetanospasmin

Answer 8

Tetanospasmin is a 150 kDa polypeptide heteromer ;2 chains - 100kDa(heavy chain) & 50kDa (light chain) chains joined by a disulphide bond.

Tetanospasmin is intra axonally transported to the motor nuclei of cranial nerves or anterior horn of spinal cord.

Question 9

What is the process?

Answer 9

1. Heavy chain binds to the lower portion of the terminal neuron
2. Leading to uncontrolled disinhibited discharge from motor neurons
3. Tetanospasmin is intra axonally transported to the motor nuclei of cranial nerves or anterior horn of spinal cord.
4. Once inside, the neuron toxin enters a retrograde transport pathway whereby it is carried proximally to the motor neuron body.
5. In the anterior horn of the spinal cord, it is then taken by presynaptic terminals of the inhibitory spinal interneurons with the aim of inhibiting the release of inhibitory neurotransmitters (glycine and GABA).
6. This results in excessive discharge from the alpha motor neurons.
7. This leads to intense muscular rigidity and spasm.
8. Muscles of the jaw, face, and head often involved first due to shorter axonal pathways.
9. Once the toxin becomes fixed to neurons, it cannot be neutralized with antitoxin. (Neuronal binding of toxin is irreversible).
10. Recovery requires the growth of new nerve terminals

Question 10

What symptoms occur after infection?

Answer 10

• Loss of reflex inhibition of antagonist muscle groups
• Co-contraction of agonist and antagonist muscles
• intensely painful spasms, may lead to fractures & tendon rupture

Question 11

What causes the autonomic tetanus symptoms?

Answer 11

Pre-ganglionic sympathetic neurons in the lateral horns and the parasympathetic centers are later affected

This leads to disinhibited autonomic discharge resulting in sympathetic over activity and excessive plasma catecholamine levels resulting in the autonomic symptoms.

Question 12

What is the natural history of the disease?

Answer 12

1. Incubation period( time from injury to first symptom): Averages 7–10 days, with a range of 3 days–3 weeks
2. Period of onset (onset time): time interval between trismus (lockjaw) and first spasm
3. 1st week - muscle rigidity and spasms, which increase in severity.
4. Autonomic disturbance usually starts several days after the spasms and persists for 1–2 week
5. Spasms reduce after 2–3 week
6. Rigidity may persist considerably longer

Question 13

What are the clinical forms of tetanus?

Answer 13

Generalized
Localized
Cephalic
Neonatal

Question 14

What is Generalized tetanus?

Answer 14

Most common form
Characterized by generalized rigidity & spasms
Trismus (lockjaw); usually the 1st
Due to masseter rigidity
Risus sardonicus: a grimace or sneer
from sustained contraction of the facial muscles

Question 15

What are the clinical features of tetanus?

Answer 15

• Stiffness and spasms of bulbar, neck, trunk and limb muscles
• Opisthotonos (arched back): Extensors are stronger than Flexors.
• Board-like abdominal rigidity
• Consciousness is preserved
• Spasms of laryngeal muscles may cause fatal asphyxia

Question 15

What are local and cephalic tetanus?

Answer 15

LOCAL TETANUS
Uncommon form and rigidity & spasms restricted to muscles around the wound.
The prognosis is excellent

CEPHALIC TETANUS
Follows wounds of the face and head and incubation period is usually short
Affected muscles are weak or paralysed

Question 16

What is Neonatal tetanus?
How is it preventable and what is the most common cause?

Answer 16

Causes > 50% of deaths from tetanus worldwide

Presentation: within a week of birth
A short history of failure to feed, vomiting, and ‘convulsions’.

Spasms are generalized
Mortality is high
Poor umbilical hygiene is the cause
Entirely preventable by maternal vaccination.

Question 17

What are the Autonomic Features of tetanus?

Answer 17

• Peripheral vasoconstriction
• Bradycardia
• Hypotension
• Sudden cardiac arrest
• Urinary retention
• Labile or sustained hypertension
• Tachycardia
• Dysarhythmia
• Hyperpyrexia
• Profuse sweating

Question 18

What is the management of tetanus?
What is the NECS principle?

Answer 18

• Diagnosis is majorly clinical i.e the history and clinical examination
• This is a medical emergency and requiring multidisciplinary approach best managed in a high dependency unit using the following principles(NECS):
• Resuscitation
• Neutralize the unbound toxin
• Eliminate the organism
• Control Spasms
• Supportive Therapy

Question 18

Discuss resuscitation as a management strategy for tetanus

Answer 18

RESUSCITATION: ABC, Brief history, examination

NEUTRALIZE UNBOUND TOXINS: Ideally, Tetanus immunoglobulin(Recombinant) 3 000-6000 units i.v. and IM. Antiserum(equine origin-horses), 10 000 units i.v. and 10,000 IM after a negative SC test dose.

ELIMINATE ORGANISM: IV METRONIDAZOLE 500mg 6hrly, Erythromycin, vancomycin, and clindamycin are alternative AVOID PENICILLINS
wound debridement, open wound dressing.

Question 19

Discuss control spasms as a management strategy for tetanus

Answer 19

CONTROL SPASMS
High dose Diazepam, up to 240 mg/day i.v. in divided doses. That is given as infusion. 40mg of diazepam into 1 pint of Normal saline run for 4hours and do it 6 times in a day.

Other alternatives: IM Chlorpromazine(25mg 12hrly stat and titrate as required), Phenobarbitone

When severe e.g with laryngospasm: Pancuronium with Artificial ventilation(ICU) or even tracheostomy(for endotracheal intubation of up to 2 weeks)

Question 20

Discuss supportive therapy as a management strategy for tetanus

Answer 20

SUPPORTIVE THERAPY :Nurse in a dark, quiet environment, NG Tube,
Adequate fluid and caloric intake : N/S alternate with 5%D/S ensure at least 4L of fluid (remove myoglobin), glucose monitoring, BP and SPO2 monitoring.
Bowel and bladder care
Regular turning in bed
Supportive Treatment in cases of autonomic dysfunction:
Inotropic support with dobutamine or dopamine
Atropine for bradycardia
Intravenous beta blockers: Esmolol, or labetalol
Verapamil : sinus tachycardia

Question 21

What are the complications associated with tetanus?

Answer 21

Respiratory: Laryngeal spasm, sedative associated obstruction, aspiration pneumonitis, pulmonary emboli ,apnoea hypoxia.

Musculoskeletal Fractures, tendon tear, muscle rupture, rhabdomyolysis, decubitus ulcer, deep-vein thrombophlebitis.

Renal: Renal failure: dehydration, sepsis, rhabdomyolosis, altered renal blood flow, urinary infection & stasis

Gastrointestinal: Ileus, weight loss, sepsis

Question 22

What occurs before discharge?

Answer 22

Institute active immunization before discharge Change diazepam to oral and can discharge on low dose diazepam Counsel patients on wound care and general approach to managing wound If completed TT immunization in a long time, advise to take booster doses If due to abortion, counsel on family planning Physiotherapy: After spams have disappeared, introduce Physiotherapy to help with muscle rigidity You can add muscle relaxants e.g Baclofen to speed up with recovering.

Question 23

What are the differentials

Answer 23

* Stiff –person syndrome * Meningitis/encephalitis * Rabies * Alveolar abscess * Strychnine poisoning * Dystonic drug reactions (e.g., phenothiazines, metoclopramide) * Hypocalcemic tetany * Neoplasms * Local infections * Hysteria

Question 24

What is the prevention of tetanus?

Answer 24

This involves vaccination using of Tetanus toxoid as form of active immunization for children , women of childbearing ages and adults ATS as passive immunization for people with open wounds.

Question 25

What are the Prognostic Indices?

Answer 25

Extremes of ages Proximity to the CNS Presence of Comorbidities Autonomic dysfunction Short Incubation period Short Period of onset Severe disease or spasms Temperature>38.5oC

Question 26

MCQ Tinea capitis Tinea corporis Tinea ungium Tinea manus Tinea crura

Answer 26

Tinea capitis - scalp Tinea corporis - trunk Tinea ungium - nail Tinea manus - hand Tinea crura - groin

Question 27

3 types of tinea pedis

Answer 27

Mocassin Interdigital Vestibullous