Spinal Pathology Flashcards
What is the difference between nerve regrowth in the PNS and CNS?
The PNS can regenerate following injury, while the CNS does not regenerate after injury in adults.
PNS growth is guided by growth cones and the environment, while CNS neurons are inhibited by factors in the adult CNS.
Define Bell’s Palsy.
Acute unilateral facial nerve weakness or paralysis of rapid onset (less than 72 hrs) and unknown cause.
It primarily affects the muscles of facial expression.
What are some potential causes of Bell’s Palsy?
- HSV
- Varicella zoster virus
- Autoimmunity
- Birth trauma
- Inflammation and edema of the facial nerve
- Compression of the facial nerve
List some risk factors for Bell’s Palsy.
- Pregnancy
- Obesity
- Diabetes
- Hypertension
- Immunocompromised states
- Upper respiratory conditions
These risk factors can increase the likelihood of developing Bell’s Palsy.
What are the signs and symptoms of Bell’s Palsy?
- Rapid onset facial muscle weakness
- Drooping of the eyebrow and corner of the mouth
- Incomplete eye closure
- Ear/postauricular pain
- Changes in taste
- Speech problems
- Hyperacusis
Symptoms can vary in presentation and severity.
What is diabetic neuropathy?
A common complication of T1 and T2 diabetes resulting in progressive distal sensorimotor polyneuropathy.
It can manifest as symmetrical sensory loss and motor weakness.
What are the main risk factors for diabetic neuropathy?
- Prolonged exposure to high blood glucose levels
- Poor glycemic control
- Age
- Hypertension - microvascular disease
- Dyslipidemia - nerve damage
- Smoking - vasoconstriction
- Alcohol use - toxic on nerves
These factors contribute to nerve damage and dysfunction.
Describe the typical presentation of diabetic neuropathy.
- Symmetrical stocking and glove distribution
- Bilateral numbness
- Tingling or burning sensation
- Muscle weakness and atrophy
- Autonomic symptoms (gastroparesis, erectile dysfunction, orthostatic hypotension, neurogenic bladder)
- pain - persistent and worse at night
Symptoms progress proximally and can lead to increased risk of falls.
What is the prognosis for diabetic neuropathy?
Usually unable to reverse, but treatment can help slow progression and decrease symptoms.
Patients often have a reduced life expectancy by three years compared to those without the condition.
What is motor neuron disease?
A group of neurological disorders that progressively damage parts of the motor nervous system, eventually resulting in death.
ALS (Amyotrophic lateral sclerosis) is the most common form.
Progressive bulbar palsy is the second most common - muscles of talking and swallowing.
What is the prognosis for ALS?
Survival from diagnosis is around 3 to 5 years.
Prognosis can vary based on the patient’s age and symptom onset.
Define multiple sclerosis.
Chronic degeneration of the myelin sheath surrounding neurons in the CNS with an autoimmune component.
It involves inflammation, demyelination, and axonal degeneration.
What are the types of multiple sclerosis?
- Relapsing and remitting
- Secondary progressive
- Primary progressive
These types differ in their progression and recovery patterns.
What is the hallmark of multiple sclerosis symptoms?
Symptoms appear at different times and locations, typically acute/sub-acute with periods of variable remission.
This variability can complicate diagnosis.
What is myasthenia gravis?
An autoimmune disease that targets the neuromuscular junction (NMJ).
What are the signs and symptoms of myasthenia gravis?
- Progressive muscle weakness
- Bulbar muscle weakness
- Ocular symptoms (ptosis, diplopia)
Symptoms typically improve with rest. Worse at night, worse on exertion
What is the role of acetylcholine in myasthenia gravis?
Autoantibodies block acetylcholine from binding to receptors at the NMJ, preventing muscle contraction.
This leads to the characteristic weakness seen in the condition.
What are the main autoantibodies associated with myasthenia gravis?
Anti-AChR (85%), Anti-MUSK (up to 15%), Anti-LRP4 (small percentage)
These autoantibodies interfere with neuromuscular transmission.
What imaging studies are used to rule out thymoma in myasthenia gravis patients?
Chest CT or MRI
Thymoma is a tumor of the thymus gland, which can be associated with myasthenia gravis.
What is the purpose of the Edrophonium test?
To assess for rapid and transient improvement in muscle strength after IV administration of edrophonium
Positive can indicate myasthenia gravis
Edrophonium is a short-acting acetylcholinesterase inhibitor.
What is the mechanism of action of Neostigmine/Pyridostigmine in myasthenia gravis treatment?
They are acetylcholinesterase inhibitors that increase the concentration of acetylcholine in the neuromuscular junction
This helps to outcompete autoantibodies.
What is the role of Prednisolone in managing myasthenia gravis?
It is a glucocorticoid = immunosuppressant = reduces inflammation hence autoantibody production and muscle degeneration
Administered at low doses to suppress the immune response.
What is the treatment for severe acute exacerbations of myasthenia gravis?
IV immunoglobulins
They neutralize autoreactive antibodies and cytokines.
What are common complications of myasthenia gravis?
Disability, impaired vision, poor speech, compromised swallow, myasthenic crisis
Myasthenic crisis is life-threatening and affects respiratory muscles causing potentially fatal difficult breathing