Tutorial 3 Flashcards
A 52 year-old man was referred for evaluation of weakness and difficulty walking. He first noticed gait difficulties six months prior to the appointment. He has experienced progressive weakness of his legs, making it difficult for him to walk downstairs. In addition, his arms and hands have become weak, making work as a carpenter very challenging. He has noticed constant twitching of his arm and leg muscles and experiences painful cramps in his legs.
Findings:
Observations:
• Nearly continuous fasciculations in all four extremities
• Atrophy is present in the left hand interosseous muscles and bilateral foot intrinsic muscles.
Sensation: intact for light touch, pinprick, and joint position sense.
Motor Function:
Muscle tone: hypertonia and spasticity bilaterally in the lower extremities
Deep tendon reflexes: Hyperreflexia bilaterally for biceps, triceps, brachioradialis, quadriceps and achilles reflexes.
Babinski’s sign present.
Muscle strength testing: There is muscle weakness bilaterally, affecting the legs more than the arms, and the right side slightly more than the left.
Questions:What is the most likely diagnosis?
Amyotrophic Lateral Sclerosis (ALS)
What are fasciculations?
fasciculations (visible twitching) – spontaneous twitches from denervated motor units (ex: tongue muscles)
What are the signs for lower motor neuron lesions? Name 6
muscle weakness, atrophy, fasciculations, reflexes, tone
muscle weakness
hyporeflexia (decreased deep tendon reflexes)
hypotonia (decreased muscle tone)
muscle atrophy – occurs as a result of denervation
and disuse
fibrillations (twitching detected by EMG) – spontaneous twitches characteristic of single denervated muscle fibres
fasciculations (visible twitching) – spontaneous twitches from denervated motor units (ex: tongue muscles)
Explain the concept of tone
Degree of muscle tension or resistance during rest or in response to stretching.
What are signs for upper motor neuron lesions?
muscle weakness, atrophy, fasciculations, reflexes, tone
muscle weakness increased no atrophy (may develop due to disuse) No fasciculations Hyperreflexia- increased reflexes Hypertonic- Spastic (increased tone) UMNL signs positive: eg. babinski, clonus
A 24-year old man was drag racing while unrestrained on a country road when he lost control of his car. The car rolled several times and he was thrown approximately 20 metres from the vehicle. When he was brought to emergency, radiographs revealed a C5-C6 fracture / subluxation; a skull fracture was ruled out. On physical examination by the physician in emergency, the man had absent deep tendon reflexes below the C6 level.
At this stage in the injury, what do the findings above indicate?
Spinal Shock
What is spinal shock?
Spinal shock is a combination of areflexia/hyporeflexia and autonomic dysfunction that accompanies spinal cord injury. The initial hyporeflexia presents as a loss of both cutaneous and deep tendon reflexes below the level of injury accompanied by loss of sympathetic outflow, resulting in hypotension and bradycardia.
What is clonus?
muscular spasm involving repeated, often rhythmic, contractions.
While in the gym one day for a rehabilitation session, the man experienced sudden, excessive sweating, flushing and a pounding headache. His therapist determined that his blood pressure was extremely high.
What is the name for this sudden response?
What was the likely mechanism behind this abrupt blood pressure spike?
Autonomic dysreflexia
Mechanism can vary…
may be due to exercise, tight clothing, bowel/bladder distention, noxious stimuli etc.
What is Autonomic dysreflexia?
Autonomic dysreflexia is a syndrome in which there is a sudden onset of excessively high blood pressure. It is more common in people with spinal cord injuries that involve the thoracic nerves of the spine or above (T6 or above).
