Autonomic Nervous System Flashcards
On arrival at Holyoke Hospital , Jimmy Chin, a 10 year old boy, is immobilised on a rigid stretcher so that he is unable to move his head or trunk. The paramedics report that when they found him some 50 feet from the bus, he was awake and alert, but crying and complaining that he couldn’t “ get up to find his mom” and he had a “ wicked headache”. He has severe bruises on his upper back and head, and lacerations of his back and scalp. His blood pressure is low, he is insensitive to painful stimuli below the nipples. Although still alert on arrival, Jimmy soon begins to drift in and out of unconsciousness.
Jimmy is immediately scheduled for a CT scan, and an operating room is reserved.
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Why were his head and torso immobilised for transport to the hospital?
The location of Jimmy’s lacerations and bruises and his inability to rise led paramedics to suspect a head, neck, or back injury. They immobilised his head and torso to prevent any further damage to the brain and spinal cord.
What do his worsening neurological signs ( drowsiness, incoherence, etc) probably indicate? Relate this to the type of surgery that will be performed.
The worsening neurological signs indicate a probable intracranial haemorrhage. The blood escaping from the ruptured blood vessel(s) will begin to compress Jimmy’s brain and increase his intracranial pressure. Jimmy surgery will involve repair of the damaged vessel(s) and removal of the mass of clotted blood pressing on his brain.
Assuming that Jimmy’s sensory and motor deficits are due to a spinal cord injury, at what level do you expect to find a spinal cord lesion?
Loss of motor and sensory function below the level of nipples indicates a lesion on T4
Two days after his surgery, Jimmy is alert and his MRI scan shows no residual brain injury, but pronounced swelling and damage to the spinal cord at T4. On physical examination, Jimmy shows no reflex activity below the level of the spinal cord injury. His blood pressure is still low. Why are there no reflexes in his lower limbs and abdomen?
Jimmy is suffering from spinal shock, which occurs as a result of injury to the spinal cord. Spinal shock is a temporary condition which all reflex and motor activities caudal to the level spinal chord injury are lost, so Jimmy’s muscles are paralysed. His blood pressure is low due to the loss of sympathetic tone in his vasculature.
Over the next few days, his reflexes return in his lower limbs and become exaggerated. He is continent. Why is Jimmy hyperreflexive and incontienent?
Jimmy’s exaggerated reflexes are caused by damaged upper motor neurons axons in the spinal cord. These upper motor neurons normally inhibit spinal reflexes. He is incontinent because there are no longer pathways to support voluntary control of bowel and bladder emptying.
On one occasion, Jimmy complains of a massive headache and his blood pressure is way above normal. On examination, he is sweating intensely above the nipples but has cold, clammy skin below the nipples and his heart rate is very slow.
What is this condition called and what precipitates it?
This condition is called autonomic dysreflexia ( or autonomic hyper reflexia). This condition in which a normal stimulus triggers a massive activation of autonomic neurons.
How does Jimmy’s excessively high blood pressure put him at risk?
Extremely high arterial blood pressure can cause a rupture of the cerebral blood vessels ( as well as other blood vessels in the body) and put Jimmy’s life at risk.
