EMQs in Clinical Medicine.pdf - Peshawar Medical College

Drugs and immunity – answers 247
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of time elapsing between transfer of infection and onset of symptoms.
The classic form of rabies is known as ‘furious rabies’.
Symptoms in the prodromal period include fever, malaise, headache and
itching at the site of the bite. The patient may become agitated, hallucinate
and exhibit bizarre behaviour. The patient should be nursed in a
quiet, darkened room because the hallmark of furious rabies is hyperexcitability
to auditory and visual stimulation. Hydrophobia is present as
a result of severe pharyngeal spasm when the patient attempts to eat or
drink. Death is inevitable once the classic signs appear.
A 21-year-old man returning from a camping holiday presenting with
diplopia and photophobia develops cardiorespiratory failure.
This is the presentation of botulism. It should be remembered that the
symptoms occur with no gastrointestinal signs. There is marked
cholinergic blockade. Respiratory insufficiency can be considerable and
therefore there should be no delay in intubating patients if it is deemed
necessary.
A 40-year-old woman with multiple sclerosis (MS) is prescribed
medication to reduce the number of relapses.
Interferon- has been shown to reduce the number of plaques/lesions
seen on magnetic resonance imaging (MRI) over time in patients with
MS. Patients should be referred to a neurologist to establish whether
treatment is indicated.
Interferon- is indicated in chronic hepatitis C infection.
A 30-year-old woman presents with a laceration on her hand sustained
while gardening. She has not had any injections in the last 15 years.
Post-exposure prophylaxis with tetanus immunization is indicated.
Tetanus vaccine stimulates the production of protective antitoxin.
The infective agent responsible is Clostridium tetani, the spores of which
are often found in soil. Pathology results from the release of an exotoxin.
The neurotoxin responsible (tetanospasmin) causes disinhibition at motor
synapses and promotes neuromuscular blockade, giving rise to the characteristic
skeletal muscle spasm. The most obvious sign of generalized
tetanus is the appearance of ‘lockjaw’ (trismus caused by masseter
muscle spasm). Facial muscle spasm gives rise to the characteristic risus
sardonicus (grinning expression). Progressive muscle spasm causes
arching of the neck and back muscles (opisthotonus). Laryngeal spasm
impairs ventilation and can be life threatening.
The patient usually presents with non-specific symptoms of fever, headache
and general malaise before the onset of the classic pathognomonic signs.
Active immunization with tetanus toxoid is given along with pertussis
and diphtheria vaccine during the first year of life. Boosters are given
before school/nursery school entry and in early adulthood. In this
scenario tetanus immunization should be administered because more
than 10 years have elapsed since the previous booster.