Tetanus

TetanusMary & Victoria

Tetanus•What is Tetanus?•The Biology: Clostridium tetani•Prevention by Vaccination•Treatment

WHAT IS TETANUS? Bacterial disease Affects the nervous system Often caused by infection to cuts/wounds, especially

when they are deep Other causes:

Burns Abortion Frostbite IV drug abuse

Oposthotonus, by Sir Charles Bell (1809). Source: http://www.brown.edu/Courses/Bio_160/Projects2004/pertussis/diphther.htm

WHAT IS TETANUS? Continual excitatory discharge of the motor and

autonomic nervous system

Uncontrollable muscle spasms may lead to respiratory or cardiac arrest, and severe BP changes

– Lockjaw– Suffocation– Muscle

rigidity/spasms

– Stiffness– Bell’s Palsy– Dysphagia

WHAT IS TETANUS?

Uncommon Affects a specific area

of the body Same area as the

infection site May be a precursor to

generalized tetanus

Most common Symptoms may

progress in a descending pattern

Frequent muscle spasms lasting several minutes

Localized TetanusGeneralized Tetanus

WHAT IS TETANUS?

Affects newborns without passive immunity from their mother

Usually due to infected umbilical stump

Rare in U.S., but prevalent in underdeveloped countries

Neonatal Tetanus

Neonatal Tetanus ID# 6374 (1995). Source: Center for Disease Control--Public Health Image Library

WHAT IS TETANUS?

Rare form Mainly involving the

facial nerves Sometimes occurs

with ear infections, or after head injury

Cephalic Tetanus

Man with Cephalic Tetanus ID# 1657 (1965). Source: Center for Disease Control--Public Health Image Library

INCIDENCE OF TETANUS Decreased prevalence in industrialized nations Tetanus is rare in the U.S. due to immunizations

and improved wound care Approximately 5 deaths per year

In the U.S. it affects mostly older people Gardening during retirement years Mortality rate in the elderly: >50%

INCIDENCE OF TETANUS Worldwide public health issue

Ninth most common cause of death due to infectious disease

Approximately 250,000 deaths per year Global fatality rate: 30-50%

Neonatal tetanus Mortality rate: 90%

THE BIOLOGY: CLOSTRIDIUM TETANI Obligate anaerobe Bacillus

About 0.3-1.1µm by 3-12µm

Gram-positive Mesophile Endospores

“drum-stick” shape Motile

Some may produce flagella 3-4 times it’s length

Gram Stain of Clostridium tetani –ID#6372 (1995). Source: Center for Disease Control--Public Health Image Library

THE BIOLOGY: CLOSTRIDIUM TETANI Clostridium tetani

Produces two exotoxins: Tetanospasmin—neurotoxin that causes muscle spasms Tetanolysin—no known clinical significance

Incubation period = 3 - 14 days Produces spores

Extremely resilient to temperature, moisture, chemicals, and even 10-15 minutes of autoclaving (121˚C)

Germination occurs when exposed to anaerobic conditions such as wounds and tissue necrosis

THE BIOLOGY: CLOSTRIDIUM TETANI Commonly found in:

Soil Manure/human & animal feces Dust Rust

Noncommunicable

THE BIOLOGY: CLOSTRIDIUM TETANI Tetanospasmin:

Excreted into the bloodstream Travels through nerves or by lymphocytes to CNS Attach to presynaptic inhibitory nerve endings

Blocks the release of inhibitor neurotransmitters, causing muscle spasms

One of the most potent toxins known Lethal dose:

175 nanograms for a 154lb/70kg person (That’s 0.000175 miligrams!!)

PREVENTION BY VACCINATION The best way to prevent Tetanus is by

vaccination Virtually 100% efficacy rate in properly

immunized people

Girl Receives Vaccine–ID#9297 (2006). Source: Center for Disease Control--Public Health Image Library

PREVENTION BY VACCINATION Three types of Vaccines:

DTaP vaccine (Diphtheria, Tetanus, Pertussis) DT vaccine (Diphtheria, Tetanus) Td Vaccine (Tetanus, Diphtheria)

PREVENTION BY VACCINATION DTaP:

“3-in-1” Recommended for childhood immunization

Protects against Diphtheria, Tetanus, and Pertussis

Given 5 doses (2 months, 4 months, 6 months, 15-18 months, 4-6 years)

Only for children under age 7

PREVENTION BY VACCINATION DT

“2-in-1” For children less than 7 years old. If a child has an allergic reaction to the Pertussis

vaccine in DTaP.

PREVENTION BY VACCINATION Td

“2-in1” Adult vaccine Slightly differs in dosage of Diphtheria vaccine

than in DT. Anyone over the age of 7 Injected, usually in arm

PREVENTION BY VACCINATION T Vaccine:

A vaccine for Tetanus by itself can be given (Tetanus Immune Globulin/HTIG)-Injected into arm-Made from blood of person or animal containing antibodies against Tetanus

Typically for an adult who is having a dirty wound/injury taken care of

TREATMENT Although

immunization is available, Tetanus is not eradicated.

TREATMENTThose at risk: Lack of immunization Partial Immunization Fully immunized patients have still been

documented to contract the disease Very rare

TREATMENT Main Goals:

Use a method of attacking the anaerobic, spore-forming bacillus

Find a way around the actions of the nervous system caused by the Tetanus toxin

TREATMENT Recognition of Tetanus

Vital to the victim Stabilize and Resuscitate Neutralize Tetanus Toxin Clean wound with antibiotics Treat any muscle spasms Control Pain

TREATMENT Resuscitation

Most common cause of death in Tetanus is due to respiratory failure.

Can be a general complication of the disease, failure to treat spasms quickly enough, or as a side effect of medications.

Tracheotomy is performed as precaution.

Helps to prevent a stimulus from causing another spasm.

TREATMENTBenzodiazepines 1. Diazepam

2. MidazolamSpasm Control and Sedation

GABA-B Agonist 1. Inthrathecal baclofen Spasm Control Refractory to BZ

Muscle Relaxant 1. Dantrolene Spasm Control Alternative

Neuromuscular blocking agents

1. Vecuronium2. Pancuronium3. Succinylcholine

Spasm Control Refractory to BZ, Minimize Sedation

Antibiotics 1. Metronidazole2. Benzyl Penicillin3. Benzathine Penicillin

Elimination of C. Tetani Toxin

Alpha and Beta Blocker 1. Labetalol Control of Autonomic Dysfunction

Alpha 2 Agonist 1. Clonidine Control of Autonomic Dysfunction

Opioid 1. Morphine Sulfate Control of Pain and Peripheral Vasodilatation

Detoxified Exotoxin 1. DTaP2. Tetanus Toxoid

Active Immunization

Human Immunoglobin 1. HTIG Passive Immunization, Neutralizes Free Exotoxin, Treatment of Tetanus, Post exposure

Class Drug Indication

TREATMENT HTIG (immune globulin)

Tetanus toxin binds to nerve endings that normally calm the muscle, blocking the inhibitory signals.

HTIG neutralizes the free form tetanospasmin toxin by binding to it, prohibiting it from blocking signals

Frees the neurotoxin without crossing blood brain barrier

TREATMENT Administration of Td

Contracting the disease does not ensure immunity

Injected simultaneously with HTIG Enhances short-term (passive) immunity and

long-term (active) immunity.

TREATMENT Eliminating the toxin:

Excision – Surgical removal of the toxin producing organisms.

Creates an aerobic environment, hindering the growth of C. tetani spores

Only to be done after Td is given to the patient due to the release of tetanospasmin during the procedure

TREATMENT Antibiotic mode of action depends on which

antibiotic is used Metronidazole is used most often for tetanus

Works by inhibiting nucleic acid synthesis

QUESTIONS??