Week 12 Neuro Part 2 Flashcards
Restless leg syndrome - what is it? When does it occur?
-common sensorimotor disorder associated with unpleasant sensations (prickling, tingling, crawling) and undesired periodic leg movements
-occur at rest and worse in the evening or at night
-powerful urge to move legs for relief-can significantly affect sleep/QOL
Are periodic limb movements always a part of restless leg syndrome?
No, can just be uncomfortable sensations that make you want to move your legs… periodic limb movements during sleep is considered its own disorder
What populations experience restless leg syndrome more commonly?
more common in women, during pregnancy, older persons and individuals who are iron deficient
When are the uncomfortable sensations of restless leg syndrome worse? (2)
- During rest/inactivity
- At night
How common is it for those with restless leg syndrome to also have periodic movements of sleep (PLMS)?
Approximately 85% of patients with RLS have periodic movements of sleep, usually involving the legs (periodic leg movements of sleep [PLMS]). PLMS is characterized by involuntary, forceful dorsiflexion of the foot lasting 0.5-5 seconds and occurring every 20-40 seconds throughout sleep.
Are sleep disturbances, daytime fatigue, and involuntary jerking movements (either while asleep or awake) part of the diagnostic criteria for RLS?
No, but they are features commonly associated with restless leg syndrome
What do you need to test for in all patients with RLS?
Iron deficiency
Do we routinely do sleep studies for people with RLS?
NO, but Polysomnography may be necessary to quantify PLMS or to characterize sleep architecture, especially in children and in patients who continue to have significant sleep disturbances despite relief of RLS symptoms with treatment
**Sleep disturbances may be associated with RLS but are not part of the diagnostic crtieria
What are some non-pharmacologic treatments of RLS?
Sleep hygiene measures
Avoidance of caffeine, alcohol, and nicotine in patients with mild RLS who are sensitive to these substances
Discontinuation, when possible, of medications that cause or exacerbate RLS, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinepherine reuptake inhibitors (SNRIs), diphenhydramine, and dopamine antagonists
Exercise
Physical modalities before bedtime, such as a hot or cold bath, whirlpool bath, limb massage, and vibratory or electrical stimulation of the feet and toes
What is Periodic Limb Movements Disorder? (PLMD)
Is sleep disorder
Often co-exists with restless leg syndrome, but is a distinct and mutually exclusive diagnosis
Movements occur AFTER You fall asleep (RLS is more about what leg discomfort BEFORE sleep)
characterized by a clinical sleep disturbance attributed to an increased number of PLMS (periodic limb movements of sleep), in the absence of alternative causes of the sleep complaints.
Cause of PLMS?
Causes largely not understood, but seems to be associated with many of same conditions as RLS: low ferritin levels, medications,
According to Wikipedia…PLMS seems to have an origin in the spinal cord. In fact, PLMS was suggested to be associated with increased spinal reflexes. Manifestations of PLMS seem to occur mostly in disorders associated with dopaminergic dysfunctions
Do periodic limb movements of sleep occur during REM or NREM sleep?
Occurs during non-REM sleep stages (do not occur during REM due to muscle atonia)
S&S of periodic limb movement disorder?
Usually manifests as daytime somnolence
Wake up with cramps or “Charlie horse” In legs
Often not aware of these movements at all, unless someone else points them out (bed partner may complain of person kicking them during sleep)
During night, leg twitching or jerking (usually flexion) movements during sleep occurring every 15 to 40 seconds.
Do you need to do a sleep study to diagnose perioid limb movement disorder? What is included in the diagnostic criteria?
Yes! (unlike RLS)
diagnosed based on a clinical history of sleep disturbance or daytime fatigue, combined with polysomnography (PSG) showing an excessive number of periodic limb movements of sleep (PLMS), and exclusion of alternative causes of the sleep complaints.
Diagnostic criteria = more than 15 periodic limb movements per hour of sleep time in adults (more than 5 in children), causing clinically significant sleep disturbance or impairment in function or wellbeing not explained by some other entity
PLMD is a diagnosis of exclusion and cannot be diagnosed in the context of other sleep disorders that have already been diagnosed, such as RLS, OSA, and narcolepsy (because these present with very similar movements)
What areas of muscle does the ulnar nerve innvervate?
some forearm and most hand muscles
- Flexor carpi ulnaris muscle
- The ulnar half of the flexor digitorum profundus muscle in the anterior forearm
- Most of the intrinsic hand muscles: hypothenar muscles, two lumbricals, adductor pollicis muscle, all the interossei muscles (palmar and dorsal)
What is happening when you feel like you “hit your funny bone”?
The ulnar nerve is vulnerable as it passes posterior to the medial epicondyle of the humerus
This causes the “I hit my funny bone” tingling sensation
What spinal nerves does the ulnar nerve originate from?
From the brachial plexus: spinal nerves C7, C8 and T1
The ulnar nerve is a terminal branch of the medial cord of the brachial plexus. It contains mainly fibers from the anterior rami of spinal nerves C8 and T1, but may sometimes carry C7 fibers as well.
Is the ulnar nerve motor or sensory or both?
Why is it considered one of the most clinically relevant nerves of the upper limb?
From its origin, the ulnar nerve courses distally through the axilla, arm and forearm into the hand. It is a mixed nerve and provides motor innervation to various muscles of the forearm and hand as well as sensory supply to the skin of the hand.
The ulnar nerve can broadly be described as the nerve of the hand, as it innervates the vast majority of the intrinsic hand muscles. It is one of the most clinically relevant nerves of the upper limb, due to its superficial course and clinically apparent role in hand function.
S&S of diabetes-associated peripheral neuropathy?
Distal symmetrical sensorimotor polyneuropathy with glove and stocking loss of sensations such as: pain, vibration, temperature, proprioception.
Loss of motor function with clawed toes and small muscle wasting in hands and flexor muscles
Charcot joints: loss of sensation results in joint and ligament degeneration, particularly of the foot
Numbness
Loss of balance
Tingling
Pain
Clinical tests to screen for diabetes associated peripheral neuropathy
Careful history
Assessment of small nerve fibre function by testing thermal or pin prick sensation and light touch perception with a 10 g monofilament on the dorsal aspect of the distal great toe
Assessment of large nerve fibre function by testing vibration sensation with a 128 Hz tuning fork, proprioception (joint position sensation), and deep tendon reflexes at the ankle as compared with more proximal locations
Ankle and patellar deep tendon reflexes
Extension of the big toe, ankle dorsiflexion, and walking on heels to test motor strength
Romberg test, normal gait, and tandem gait to assess balance and fall risk. Pt stands with feet together (a soldier at attention) then they close their eyes.
Clinical assessment of the lower legs and feet to look for any ulceration or deformity
Causes of upper motor neuron lesions? What areas would the lesions be in to cause upper motor neuron issues?
Any injury to brain (stroke, infection, tumors), brainstem, or white matter of spinal cord.
What is a lower motor neuron lesion? Where is it occuring?
- Any damage to the lower motor neuron axon, which goes from the spinal cord to the muscle.
- Any injury to the ventral grey matter of the spinal cord (because this is where the lower motor neuron starts)
What effect does an upper motor neuron lesion have on deep tendon reflexes? Superficial reflexes?
Deep tendon are HYPERFLEXIC –> reflex becomes amplified because upper motor neurons are not able to regulate reflex at that level.
Superficial reflexes - diminished or absent
(Babinski reflex is positive)
Do you see muscle atrophy more in upper or lower motor neuron lesions?
Lower, because lower is what would normally deliver impulse to muscles directly. (may see weakness but not so much atrophy in upper motor neuron lesions)
Would you see a plantar response (babinski) if lower motor neuros lesions?
No
What is the effect of lower motor neuron lesions on deep tendon reflexes?
Absent
Would you see fasciculations in muscles with upper or lower motor neuron lesions?
Lower…. in this case, muscle may be affected but are still some single muscle fibres that are still stimulated (still some transmission from lower motor neurons that are not injured)
How common is huntington’s disease? How likely are you to inherit it if parents have it?
~ 1 in 7000 people affected in Canada
Hereditary
If one parent has HD 50 % chance, it’s passed on –> Is autosomal DOMINANT trait
Patho of huntington’s disease (HD). What chromosome is affected?
HD defect is on chromosome 4
Short version: abnormal DNA sequencing –> abnormal protein formation –> altered motor & mental functions
Repeated sequence of DNA (CAG nucleotides) causes formation of abnormal Protein leading to altered motor and mental functions
People with HD have 36 or more CAG (Glutamine) repeats on Huntingtin (HTT) gene (also referred to Polyglutamine disease) Normal: 10-35 times in a row
Chains of glutamine stick together and contribute to neuronal loss
Progression leads to tissue loss in basal ganglia
Recap Basal Ganglia Function: involved in motor function by providing feedback mechanism to motor cortex for initiation & control of voluntary movements
Regions affected by HD have decrease GABA and Acetylcholine and increased Dopamine levels
When does huntington’s usually present? Is it fatal? Fast or slow to progress?
Progressive, slow, fatal
Onset is usually around 40 years of age
The more repeats of CAG the earlier the onset of symptoms
Neuroradiological abnormalities can occur up to 15 years before clinical symptoms
What are the motor symptoms of huntington’s disease
Movement inhibition
Excessive involuntary movements
Hypotonia with hyperreflexia (early symptom), chorea (ex. Face, head, neck, tongue, trunk, extremities), athetosis, dystonia, eye movement slows, gait abnormalities (unsteady, irregular -> bradykinesia, rigidity late in disease)
What are the psychiatric, cognitive, and physical appearance symptoms of huntington’s disease
Apathy, irritability, depression, delusions, aggressions, disinhibition, paranoia
Cognitive: Progressive dementia, inflexibility of thought, decreased insight and concentration, memory loss
Weight loss, cachexia
How to diagnose Huntington’s disease?
MRI shows atrophy of head of caudate nuclei
Genetic testing for CAG repeats in HTT gene. Normal = 10-35 repeats. >36 repeats = HD
Other: History, physical examination
neurological: motor and mental status exams
Common causes of peripheral neuropathy?
commonly from diabetes mellitus, alcohol abuse, HIV infection
Other systemic causes of neuropathy (mostly axonal polyneuropathies) include chronic HIV infection, critical illness, end stage kidney disease, amyloidosis, hypothyroidism, vitamin deficiencies, lyme disease
Autoimmune polyneuropathies (most notably Guillain-Barre syndrome) are mostly demyelinating neuropathies
Toxic polyneuropathies are mostly from toxins including alcohol, chemotherapy exposure, heavy metals (causes a predominantly axonal polyneuropathy that could be acute, subacute or chronic
How do we describe the typical distribution of onset of peripheral neuropathy? What symptom is characteristic of acute polyneuropathies?
Weakness of lower legs and hands start as the syndrome progresses (the classic “stocking and glove” distribution of sensory loss)
Some polyneuropathies are acute (mainly caused by toxins), and those are characterized by pain
In peripheral neuropathies, do you typically see onset of sensory symptoms or motor symptoms first? What cause is a relatively common exception to this?
Sensory
Guillain Barre syndrome mostly affects motor neurons, and is an acute demyelinating polyneuropathy, and tends to first present with weakness instead of sensory loss
Diagnostic testing for peripheral neuropathies?
Clinical exam, extensive diagnostic testing usually unnecessary if mild symptoms with a known underlying cause (ie. Diabetes, alcohol abuse or chemotherapy)
Full diagnostic testing is warranted for those with no clear cause, or if symptoms are severe and rapidly progressive
Electrodiagnostic testing (with electromyography- EMG- and/or nerve conduction studies are initial testing when there is no clear etiology, or symptoms are rapidly progressive or severe
What are some s/s of Obstructive Sleep Apnea Syndrome (OSAS)?
Excessive loud snoring
Gasping
Multiple apneic episodes (temporary pause of breathing) that lasts 10 seconds or longer
What are some related progressions/manifestations that may be seen/associated in a patient with OSAS?
Obesity hypoventilation syndrome: may be r/t leptin resistance (leptin is a resp stimulant).
OSAS leads to hypercapnia and decreased O2 sats -> eventually leads to polycythemia, pulmonary hypertension, systemic hypertension, stroke, right-sided heart failure, dysrhythmias, liver congestion, cyanosis, and peripheral edema.
Hypersomnia (excessive daytime sleepiness) – can be so severe that people may fall asleep while talking, working, driving.
Impaired mood and cognitive function; symptoms include impairment of attention, episodic memory, working memory, and executive functions.
What are some treatment options for a person with OSAS?
CPAP, dental devices, surgery of upper airway and jaw if indicated, and obesity management
