Transcript An update on tetanus - Beyond Conformity

An update on tetanus
Clinical features
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CLINICAL FEATURES
 The incubation period varies from 3 to 21 days,
usually about 8 days. In general the further the
injury site is from the central nervous system, the
longer the incubation period.
 The shorter the incubation period, the higher the
chance of death. In neonatal tetanus, symptoms
usually appear from 4 to 14 days after birth,
averaging about 7 days.
 The period between the first symptom and the
first spasm is referred to as the onset time.
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CLINICAL FEATURES
 three different forms of
tetanus have been
described:
1) Local tetanus
2) Cephalic tetanus
3) Generalized tetanus
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Local tetanus
 Local tetanus is an uncommon form with an
incidence of about 2% with manifestations
restricted to muscles near the wound.
 The incubation period is long and spasms may
spread from one limb to the other . These
contractions may persist for many weeks before
gradually subsiding.
 Local tetanus may precede the onset of
generalized tetanus, but is generally milder. Only
about 1% of cases are fatal.
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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.
 Facial paralysis and diplopia due to paralysis of
the eye muscles are the common findings. The
diagnosis may be missed initially but the other
symptoms like trismus dysphagia and spasms
follow very rapidly in the majority of cases.
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generalized
tetanus.
 The disease usually presents with a descending
pattern. The first sign is trismus or lockjaw,
followed by stiffness of the neck, difficulty in
swallowing, and rigidity of abdominal muscles.
 Other symptoms include a temperature rise of 2°4°C above normal, sweating, elevated blood
pressure, and episodic rapid heart rate.
 Spasms may occur frequently and last for several
minutes.Spasms continue for 3-4 weeks.
Complete recovery may take months.
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generalized
tetanus.
 Spasms with intervening rigidity (being
greater in the trunk than the limbs) occur
both spontaneously and on stimulation and
varies in severity. Arching the trunk opisthotonus is a feature during the
established disease. Periods of apnoea
may occur due to spasm of the intercostal
muscles and the diaphragm.
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generalized
tetanus.
 Autonomic dysfunction occurs in the more
severe cases and sets in a few days after
the spasms due to the slower intra axonal
transport to the lateral horn cells.
 It consists of a basal sympathetic activity
characterized by a resting tachycardia and
depression of bowel motility and bladder
dysfunction.
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generalized
tetanus.
 Episodes of severe sympathetic overactivity (SOA)
which includes fluctuating tachycardia, labile
hypertension, sweating and pyrexia takes place
both with and without stimulation. Profuse
salivation and bronchial secretions due to
increased parasympathetic activity also occur. All
these signs do not necessarily occur concurrently
and its severity varies from patient to patient.
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generalized
tetanus.
 Episodes of bradycardia and hypotension some
times lead to cardiac arrest, These signs have
been explained on the basis of increased
parasympathetic activity, but many attribute it to
sudden withdrawal of sympathetic activity as the
bradycardia does not always respond to atropine.
Cardiac arrest in tetanus has also been attributed
to myocardial damage caused by high
catecholamine levels and toxic damage to the
brainstem.
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Neonatal tetanus
 is a form of generalized tetanus that occurs in
newborn infants. Neonatal tetanus occurs in
infants born without protective passive immunity,
because the mother is not immune.
 It usually occurs through infection of the unhealed
umbilical stump, particularly when the stump is cut
with an unsterile instrument.
 Neonatal tetanus is common in some developing
countries (estimated >270,000 deaths worldwide
per year)
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Neonatal tetanus
 Neonatal tetanus presents most often about
the seventh day of life with a short history of
failure to feed. Spasms are typical but the
diagnosis can be mistaken for meningitis or
sepsis .
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Classification &clinical grading
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2)
3)
4)
A useful method of grading the severity of tetanus for the
purposes of management and study was devised by
Ablett
Ablett classified the disease into the following grades:
Grade I (Mild) :trismus
Grade II (Moderate) :Muscle rigidity (trismus, dysphagia,
risus sardonicus neck rigidity, opisthotonus) and fleeting
spasms not embarrassing respiration
Grade III a (Severe) :Muscle rigidity and severe spasms
Grade IIIb (Very severe) :Muscle rigidity, severe spasms
and autonomic dysfunction
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Classification &clinical grading
we adopted a modification of Ablett classification
which we cosidered to be more useful in the
prognosis and management:
1. Grade 1(mild):muscle rigidity affecting one or
more group of muscles sparing the muscles of
deglutition
2. Grade 2(moderate):muscle rigidity involving the
muscles of deglutition
3. Grade3a(severe):musle rigidity and reflex
spasms
4. Grade 3b(very severe):autonomic nervous
system changes are added
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Classification &clinical grading
These modifications are justified by the following
observations:
1) Muscle rigidity whether localized or generalized has the
best prognosis provided that the patient can swallow.
Moreover, the more severe forms of disease are usually
discharged from hospital with muscle rigidity that will take
weeks to disappear.
2) Involvement of the muscles of deglutition adds 2 causes
for morbidity (aspiration pneumonia and dehydration)
that need special care.
3) All patients with reflex spasms are considered severe
because even with infrequent fits, some patients
unpredictably develop a shower of fatal spasms.
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COMPLICATIONS
 Laryngospasm (spasm of the vocal cords)
and/or spasm of the muscles of respiration
leads to interference with breathing.
 Fractures of the spine or long bones may
result from sustained contractions and
convulsions.
 Hyperactivity of the autonomic nervous
system may lead to hypertension and/or an
abnormal heart rhythm.
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COMPLICATIONS
 Nosocomial infections are common
because of prolonged hospitalization.
Secondary infections, which may include
sepsis from indwelling catheters, hospitalacquired pneumonias, and decubitus ulcers.
 Pulmonary embolism is particularly a
problem in drug users and elderly patients.
 Aspiration pneumonia is a common late
complication of tetanus, found in 50%-70%
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of autopsied cases.
COMPLICATIONS
 J Neurol Neurosurg Psychiatry. 2003
Oct;74(10):1432-4 :Brain
lesions in
the course of generalised
tetanus.
MRI on the 82nd hospital day revealed cortical
and subcortical lesions predominantly in the right
frontal and parietal lobes in addition to marked
brain atrophy.
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COMPLICATIONS
 J Anesth. 2000;14(4):204-6. Ruptured
superior mesenteric artery
aneurysms during
treatment of tetanus: a
case report.
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COMPLICATIONS
 Mov Disord. 2003 Oct;18(10):1204-6.
Brainstem myoclonus in
generalised tetanus.
Electrophysiological studies of stimulus
sensitive myoclonus in a man with
generalized tetanus revealed features
characteristic of hyperekplexia or brainstem
myoclonus.
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COMPLICATIONS
 Acta Orthop Belg. 2003 Jun;69(3):285-8. A
case of myositis ossificans
as a complication of tetanus
treated by surgical excision
We report a case of myositis ossificans
following tetanus in a female adult patient
presenting with ankylosis of both elbows in
extension.
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Diagnostic tests
1) Spatula test: Apte and Karnad described a
simple bedside test to diagnose tetanus:
The posterior pharyngeal wall is touched
with a spatula and a reflex spasm of the
masseters indicates a positive test. This
occurred in 349 of the 350 patients with
tetanus (sensitivity 94% and in no patient
without tetanus (specificity 100%)
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Diagnostic tests
2. The altered whistle in tetanus: Eric R
Dunn MJA 2002 177 (11/12): 687
The alteration of a person's
whistle in tetanus can be
explained as an early effect of the
increased tone in facial muscles,
which causes the classic risus
sardonicus.
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Differerential diagnosis
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Strychnine poisoning
Dental infections
Local infections
Hysteria
Neoplasms
Encephalitis
dystonia
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