TETANUS
• Tetanus is an acute disease caused by
an exotoxin produced by Clostridium
tetani.
• It is characterized by generalized
rigidity and convulsive spasms of skeletal
muscles. The muscle stiffness usually
involves the jaw and neck and then
becomes generalized.
TETANUS
• Infection generally occurs through wound
contamination and often involves a cut or
deep puncture wound.
How serious is tetanus?
• Tetanus has a high fatality rate: about 10%
of reported cases result in death.
TETANUS
• C. tetani is an anaerobic gram-positive
bacillus
( spore-forming bacteria)
• Spores found in soil, dust, animal feces;
may persist for months to years
• Tetanus is not spread from person to person
Spores are introduced into tissues after a
penetrating injury.
Neurotoxins in tetanus
Clostridium tetani produces two exotoxins:
1.tetanolysin
(the function is not known)
2.tetanospasmin
(a neurotoxin which causes the clinical
manifestations)
Tetanus
 Tetanus toxin blocks inhibitory nerve impulses,
by preventing the release of inhibitory
neurotransmitters GABA (gammaaminobutyric acid) and glycine.
http://www.bilkent.edu.tr/~bilheal/aykonu/ay2005/mart05/tetanoz.htm
Pathogenesis
• Tetanus toxin produced in a wound can
spread centrally via intra-axonal transport
along motor nerves to the spinal cord;
• it may also spread hematogenously.
Toxin binds in central nervous system and
interferes with neurotransmitter release to
block inhibitor impulses
TETANUS
• Tetanus - is rare in industrialized countries
because of the widespread use of active
immunization.
• In the United States, fewer than 50 cases are
reported annually; at least 87% occur in
inadequately immunized persons, and 35% occur
in persons older than 60 years, which emphasizes
the need to maintain immunity in older adults.
TETANUS
• Tetanus may also occur in association with:
-pregnancy (postpartum and postabortion tetanus),
-surgery (postoperative tetanus),
-burns, vaccination, intramuscular injections, gangrene,
chronic skin ulcers, dog bites, penetrating eye injuries, and
narcotics addiction
-umbilical stump infection in newborns (neonatal tetanus)
• In 10% to 20% of patients with tetanus, there is no history
of injury or evidence of an infected lesion
Pathogenesis
• The incubation period between injury and onset of
symptoms ranges from 1 to 55 days. In more than
80% of patients, symptoms begin within 14 days.
• The length of the incubation period is a valuable
prognostic sign in patients younger than 50 years:
- mortality is almost 100% when this period is
only 1 or 2 days but 35% to 40% when it is more
than 10 days.
Tetanus
• Terms describing the initial stages of tetanus
include the incubation period (time fran
inoculation to the first symptoms) and the
period of onset (time from the first
symptom to the first generalized spasm)
The shorter these periods are, the higher the
risk of death is.
Tetanus Clinical Forms
•
1)
2)
3)
Clinical forms:
local (not common),
cephalic (rare),
generalized (most common, representing
80% of cases)
4) neonatal tetanus
Generalized tetanus
The usual presenting symptoms are:
- restlessness;
- pain caused by muscle spasm;
- stiffness of the back, neck, thighs and abdomen.
- difficulty in opening the mouth (trismus, or
lockjaw-masseter rigidity), the hallmark of
tetanus; this is the first symptom in more than
50% of patient
- risus sardonicus (facial spasm / sneering
expression)
Generalized tetanus
• The generalized spasm consists of
opisthotonic posturing with flexion of the
arms and extension of the legs.
• During the spasm, the upper airway can be
obstructed, or the diaphragm may
participate in general muscular contraction.
Opisthotonus
TETANUS
TETANUS
Generalized tetanus
• Sudden stimuli (e.g., bright light or noise)
can precipitate tonic seizure, accompanied
by diaphragmatic, intercostal, glottal, or
laryngeal spasm, and result in hypoxia and
respiratory arrest
• Spasms may occur frequently and last for
several minutes.
• Spasms continue for 3–4 weeks.
Generalized tetanus
• Labile hypertension, tachycardia,
arrhythmias, profuse sweating, marked
intermittent vasoconstriction, tachypnea,
and hypotension may occur singly or in
varying combinations.
Generalized tetanus
• The complications of tetanus are
respiratory arrest secondary to tetanic spasms,
pneumonia secondary to aspiration, pulmonary
emboli,
 cardiac problems related to sympathetic
overactivity or to cardiomyopathy,
 fractures of thoracic vertebrae caused by
violent spasms.
Cephalic tetanus
Is a rare form of the disease, occasionally
occurring with otitis media (ear infections)
in which C. tetani is present in the flora of
the middle ear, or following injuries to the
head.
There is involvement of the cranial nerves,
especially in the facial area.
Localized tetanus
• Localized tetanus is characterized by intermittent
painful spasms of muscles in the same anatomic
area as the injury
• The stiffness and spasms may persist for weeks in
the local area and then gradually abate.
• Local tetanus may precede the onset of
generalized tetanus, but is generally milder.
Only about 1% of cases are fatal.
Neonatal tetanus
• Generalized tetanus in newborns
• It occurs through infection of unhealed
umbilical stump if mothers are inadequately
immunized.
Tetanus
• Tetanus is diagnosed by clinical
observation. There are currently no blood
test that can be used to diagnose tetanus.
Laboratory findings
• Blood counts, blood chemistries, and CSF
values are normal.
• C. tetani is isolated from the wound in only
30% of cases, probably because of the
fastidious anaerobic requirements of the
organism.
Differential Diagnosis
• Trismus may also be present in patients with
encephalitis, but in contrast to those with tetanus,
these patients are not fully conscious.
• Acute strychnine poisoning is the only disease that
resembles tetanus.
• Hepatic encephalopathy is sometimes associated
with prominent muscular stiffness and rigidity.
Treatment of tetanus
• Treatment of tetanus is aimed at prevention
of muscle spasms and respiratory
complications, neutralization of circulating
toxin, and elimination of the source of the
toxin.
Tetanus antitoxin
• Human tetanus immune globulin (HTIG) is
recommended for persons with tetanus.
• TIG can only help remove unbound tetanus toxin.
It cannot affect toxin bound to nerve endings.
• A single intramuscular dose of 5000 units is
generally recommended for children and adults,
with part of the dose infiltrated around the wound
if it can be identified.
Control of muscular spasms and
rigidity
• Sedation requires prevent respiratory
depression
• Diazepam is the drug of choice produces a
sedative effect without inducing depression
• Magnesium intravenous infusion prevents
muscule spasm.
Control of sympathetic
overactivity
• Propranolol and labetalol are examples of
beta-adrenergic blocking agents that have
been used in patients with tetanus to treat
marked sympathetic overactivity, including
hypertension, tachycardia, and profuse
sweating.
Antibiotic treatment
Metronidazole, in a 500 mg I.V. dose every 6
hours
Immunization
• Infants should receive diphtheria-pertussistetanus (DPT) vaccine at 2 months of age.
Two additional doses are given at 4 and 6
months of age. A booster injection of DPT
is given at 18 months and 4-6 years
• At 16 years of age, a booster dose of
combined adult-type tetanus and diphtheria
toxoids is administered.
Immunization
Teatanus-diphteria
vaccine is given
to adolescents and
adults as a booster
shot every 10 years.
Immunization
• In the event of tetanus prone-injury a
booster dose of vaccine should be given if
more than 5 years have elapsed since last
dose.
Immunization
• Adults who have not been immunized should
receive two doses of alum-precipitated tetanus
toxoid intramuscularly, 1 month apart, followed by
a booster dose after 6 months.
• Patients with wounds that are contained with dirt
or feces and who have not received adequate
active immunization in the past 5 years or in
whom immunodeficiency is suspected should
receive passive immunization with HTIG (250500 units, intramusculary) in addition to active
immunization.
Adult with classic signs of
tetanus
Child has painful muscle
contractions from tetanus
Baby has neonatal tetanus
with complete rigidity
Tetanus in a 46-year-old
man, Manila
Adult with tetanus
Baby has neonatal tetanus
Routine DTaP Primary
Vaccination Schedule
Dose
Primary 1
Primary 2
Primary 3
Primary 4
Age
Interval
2 months
4 months
6 months
15-18 months
--4 wks
4 wks
6 mos