Brief overview...

1. Rapid review…
Daniel Vela, MD
Department of Neurology
Loyola University Medical Center
February, 2013

2. Tetanus
• Clostridium tetani
• Tetanospasmin: Toxin that
interferes with the release of
inhibitory neurotransmitter causing
excessive excitation of spinal and
bulbar motor neurons.
• Sustained muscular rigidity and, in
severe cases, reflex spasms.
– Early manifestations of "The contracted"
generalized tetanus are rigidity
of the masseter muscles Opisthotonus, By Sir Charles Bell (1809)
(lockjaw) and facial muscles, Contracted body of a soldier suffering from tetanus.
with straightening of the upper
lip or risus sardonicus.
• Autonomic instability, mostly
hypersympathetic state, may occur
in severe cases.

4. Management
• Metronidazole (500 mg intravenously every 6
hours for 7 to 10 days)
• Neutralization of circulating (unbound) toxin
by antitoxin will shorten the course of disease
and lower mortality.
• Human tetanus immune globulin should be
administered promptly before manipulating
the wound.
• The recommended dose is 500 U
intramuscularly.
• Combined intrathecal (1000 U) and
intramuscular antitetanus immunoglobulin
administration gives better clinical outcomes
than intramuscular administration alone

5. Clinical Vignette
• A 32-year-old previously healthy male was brought to the emergency room because of difficulty in
swallowing and chewing. He reported having been stabbed with a nail at his right foot 7 days
previously. He did not receive any antitetanus antiserum or tetanus toxoid. His immunization record
showed that he completed primary immunization program during childhood with no booster. The
physical examination revealed trismus and rigidity involving facial and trunk muscles. The wound at
the right sole was infected. He was diagnosed as having tetanus and was admitted to the hospital.
• Human tetanus immune globulin was given intramuscularly. The wound was cleansed thoroughly.
Amoxicillin-clavulanate (1.2 g every 8 hours intravenously) and metronidazole (500 mg every 6 hours
intravenously) were given and continued for 10 days. Nasogastric tube was inserted. Diazepam was
administered intravenously to control muscle rigidity.
• Despite such treatments, his condition deteriorated in the following days. Rigidity spread to the
limbs and torso. Spasm occurred spontaneously and in response to external stimuli. Rigidity and
spasm were severe enough to compromise respiration. Endotracheal tube was inserted while the
patient remained relaxed with pancuronium. Tracheostomy was performed thereafter, and
respiration was assisted by mechanical ventilator. Pancuronium was given intravenously every 2 to 3
hours and was continued for 4 weeks. Substantial improvement was evident at the end of the fourth
week. Rigidity improved, requiring fewer doses of pancuronium. In the sixth week, rigidity was
controlled by diazepam alone. He recovered uneventfully and was discharged after 8 weeks.

6. Rabies

7. • There are two main “phenotypes”:
• Encephalitic (furious) 80%
– Agitation, delirium, seizures, nuchal rigidity, severe pharyngeal
spasms, stridor, autonomic instability, and sometimes hydrophobia
or aerophobia.
– Symptoms occur approximately 2–10 days after the prodromal
period.
• Paralytic (Dumb) rabies. 20%
– progressive paralysis until death. The clinical course is
more indolent, with a clear sensorium sometimes
preserved until late in the course.

8. Management
• Immediate and thorough
wound cleansing with
soap and water
• Human rabies immune
globulin around the
wound. (20 U / Kg)
• Rabies vaccine
intramuscularly on Days
0, 3, 7, 14, and 28.

9. Strychnine (Nonanticoagulant Rodenticide)
Mechanism
• Antagonizes glycine, an inhibitory neurotransmitter released by postsynaptic inhibitory neurons in
the spinal cord. Binds to the chloride ion channel, causing increased neuronal excitability and
exaggerated reflex arcs.
Clinical features
• Muscular stiffness and painful cramps precede generalized muscle contractions, extensor muscle
spasms, and opisthotonus. The face may be drawn into a forced grimace (risus sardonicus,
"sardonic grin").
• Muscle contractions are intermittent and easily triggered by emotional, auditory, or minimal
physical stimuli. Repeated and prolonged muscle contractions often result in hypoxia,
hypoventilation, hyperthermia, rhabdomyolysis, myoglobinuria, and renal failure.
• Muscle spasms may resemble the tonic phase of a grand mal seizure, but strychnine does not
cause true convulsions, as its target area is the spinal cord, not the brain. The patient is usually
awake and painfully aware of the contractions, described as "conscious seizures." Profound
metabolic acidosis from increased lactic acid production is common.
Management
• Airway control, quiet environment (minimize sensory stimulation), and activated charcoal. Avoid
lavage (may precipitate seizures). Benzodiazepines, barbiturates, analgesia. Neuromuscular
blockage if necessary.

10. Strychnine (Nonanticoagulant Rodenticide)
Mechanism
• Antagonizes glycine, an inhibitory neurotransmitter released by postsynaptic inhibitory neurons in
the spinal cord. Binds to the chloride ion channel, causing increased neuronal excitability and
exaggerated reflex arcs.
Clinical features
• Muscular stiffness and painful cramps precede generalized muscle contractions, extensor muscle
spasms, and opisthotonus. The face may be drawn into a forced grimace (risus sardonicus,
"sardonic grin").
• Muscle contractions are intermittent and easily triggered by emotional, auditory, or minimal
physical stimuli. Repeated and prolonged muscle contractions often result in hypoxia,
hypoventilation, hyperthermia, rhabdomyolysis, myoglobinuria, and renal failure.
• Muscle spasms may resemble the tonic phase of a grand mal seizure, but strychnine does not
cause true convulsions, as its target area is the spinal cord, not the brain. The patient is usually
awake and painfully aware of the contractions, described as "conscious seizures." Profound
metabolic acidosis from increased lactic acid production is common.
Management
• Airway control, quiet environment (minimize sensory stimulation), and activated charcoal. Avoid
lavage (may precipitate seizures). Benzodiazepines, barbiturates, analgesia. Neuromuscular
blockage if necessary.