Neuropathies Flashcards
Know:
CRPs
GB
Diabetic neuropathy
Bells and oculomotor neuropathy
Carpal tunnel syndrome
-CRPs
-GB
-DM neuropathy
-bells palsy
-oculomotor palsy
TEST
-MCC- camp jejuni
-budapest criteria dont need to know
-polyneuropathy- ignore hereditary
-lumbar sacral chart- dont need to know
-never assume neck pain radiating down to arm is MSK
complex regional pain syndrome (CRPS): definition and pathophysiology
Definition: Disorder of a body region characterized by pain and inflammation s/p injury, surgery, trauma, stroke, MI
-Occurs after fractures (MC), surgery
-Pain experienced is disproportionate to the degree of tissue injury and persists beyond the normal expected time for tissue healing
-Pain is more REGIONAL rather than dermatomal or peripheral nerve distribution (ex: just hands and not up dermatome)
Pathophysiology = multifactorial: pain dysregulation in the sympathetic and central nervous systems, with likely genetic, inflammatory, and psychological contributions
- Exact mechanism is unclear
CRPS symptoms: sensory, motor/trophic, autonomic
SENSORY:
-allodynia: non-painful stimuli cause pain
-hyperalgesia: painful stimuli cause exaggerated pain
MOTOR/Trophic
- weakness
- reduced range of motion
- tremor
- dystonia
- trophic: changes in hair, skin, nails
AUTONOMIC:
-skin color and temp changes (vasomotor dysfunction): hyper/hypopigmentation; hyper/hypothermia
-swelling and sweating changes (sudomotor dysfunction): hyperhidrosis/hypohidrosis, edema
CRPS dx and tx
Dx = clinical, uses the budapest criteria (dont memorize)
Tx:
- PT/OT
-Behavioral therapy
Pharmacotherapy:
-Anti-inflammatories, anticonvulsants, antidepressants, transdermal lidocaine, bisphosphonates
Interventions if refractory:
-Nerve blocks
-Spinal cord stimulation
A 27-year-old female with no significant medical history presents with complaint of weakness. Symptoms have been present for the past three days. She describes initial onset of bilateral leg tingling and weakness that has progressed since onset. She awoke today and had difficulty walking so presented to the emergency department (ED). She has never had these symptoms before. She recovered from a severe diarrheal illness 2 weeks ago but denies any current gastrointestinal symptoms.
Vital signs: Temperature (T) 99.0°F, heart rate (HR) 92, blood pressure (BP) 106/78, respiratory rate (RR) 18, oxygen saturation O2sat 97% on room air.
Physical exam: The patient appears fatigued but is not in any distress. Heart is regular. Breath sounds slightly diminished but otherwise clear. Lower extremity strength is 3/5 bilaterally and patellar reflexes are absent
Vital signs: Temperature (T) 99.0°F, heart rate (HR) 92, blood pressure (BP) 106/78, respiratory rate (RR) 18, oxygen saturation O2sat 97% on room air.
Physical exam: The patient appears fatigued but is not in any distress. Heart is regular. Breath sounds slightly diminished but otherwise clear. Lower extremity strength is 3/5 bilaterally and patellar reflexes are absent
guillane-barre syndrome: definition and causes
Definition: Autoimmune disorder causing destruction of PERIPHERAL nervous system MYELIN sheath/axons (somatic and autonomic) and cranial nerves causing an acute polyneuropathy
-Incidence of 1-2 per 100,000 per year
-All age groups, but changes increase with age
-Male > Female
- Infection → Abx against Postsynaptic ACh receptors
Preceding infection / trigger: ~5 days to 4 weeks before the onset of neurologic symptoms
-Idiopathic 40%
-Infections – EBV, CMV, mycoplasma, CAMPYLOBACTER JEJUNI (MC)*
-Immunizations 17%
-Surgery
-Immune response to preceding infection –> molecular mimicry of peripheral nerves –> body attacks our own nerves -> cross reaction in immune response –> demyelination that progressively gets worse
guillain barre syndrome sx
2-4 weeks after a preceding illness:
- 1st sx: Sensory disturbance: paresthesia/pain in back and limbs (54%, mild compared to weakness); stocking glove distribution
- Progressive ascending SYMMETRIC FLACCID weakness (+/- diaphragm once its C4) and loss of DTRs (94%)
-Cranial nerve involvement: fascial weakness, dysphagia, dysarthria, ophthalmoplegia - (46%)
-Autonomic dysfunction: tachycardia/bradycardia, dysrhythmias, wide variations in blood pressure, postural hypotension, urinary retention, constipation, facial flushing, anhydrosis, hypersalivation) may be present
-Severe respiratory weakness requiring mechanical ventilation: 30%**
-no brain localizing findings or fever at onset
-Symptoms peak in ~2-4 weeks, and recovery varies from weeks to a year
guillain barre syndrome dx and tests to run/workup
Dx:
-Clinical evaluation: bilateral limb paresis, hyporeflexia, sensory involvement
-LP/CSF: Albumino-cytologic dissociation: (HIGH protein (after 1 week) but normal WBC count), non-emergent
-EMG/NCS: acute polyneuropathy with either demyelinating or axonal features
-Neuroimaging: rule out spinal cord compression / cauda equina (mimic)
Negative inspiratory force (NIF) testing used to predict impending respiratory failure
-Normal NIF is >60cm of water
-Abnormal NIF <30cm (or dropping from baseline); consider PPV or intubation
what makes dx of guillian barre doubtful
-Sensory level (decrease or loss of sensation below a spinal cord root level as determined by neurologic examination) -> Points to spinal cord injury
-Marked, persistent ASYMMETRY of weakness
-Severe and persistent bowel and bladder dysfunction: conus medularis
-More than 50 white cells in the CSF: should have normal WBC
guillain barre syndrome ddx not important
-Other acute polyneuropathies: severe vitamin B1 deficiency, acute arsenic poisoning, n-hexane (glue sniffing neuropathy), vasculitis, Lyme disease, tick paralysis (mostly in children), porphyria, sarcoidosis, leptomeningeal disease, paraneoplastic disease, and critical illness.
-Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
-Continues to progress or has relapses for greater than eight weeks.
-Diseases of the spinal cord, neuromuscular junction, and muscle.
-Distinguish from cauda equina syndrome, which is often associated with bowel/bladder disturbance, and confirmed with MRI L/S spine
guillain barre syndrome tx
-Primarily supportive
-Monitor respiratory status, prevent immobility consequences, pain management
Tx indication: IVIG or Plasmapharesis
-non-ambulatory within 4 weeks of onset
- ambulatory patients not improving within 4 weeks of sx onset
peripheral neuropathy: definitioin and mononeuropathy vs polyneuropathy vs radiculopathy
Definition: Any disorder of the PNS including radiculopathies, mononeuropathies, polyneuropathy
Mononeuropathy:
- damage to a single nerve, usually due to a local cause such as trauma, compression, or entrapment.
-Example: Carpal tunnel syndrome
Polyneuropathy:
- damage to terminal branches of multiple nerves
- result: symmetrical and distal distribution
Radiculopathy:
- damage to a nerve root; distribution corresponds to the dermatome
polyneuropathy: causes and main categories
Categories: Divided into axonal and demyelinating types.
-MC = Diabetic polyneuropathy (axonal)
-Other common: alcohol abuse, and HIV infection
Systemic causes, predominantly axonal neuropathy:
-Critical Illness Polyneuropathy: a/w prolonged intubation and poor nutritional status
-Vitamin deficiencies
-Amyloidosis
-Hypothyroidism
-Lyme disease
-Toxic (predominantly axonal): Alcohol, Chemotherapy, heavy metals
Hereditary (demyelinating): Charcot-Marie-Tooth types 1A, 1B, and X-linked (ignore)
Idiopathic: 25%
polyneuropathy sx
-Symmetric distal sensory loss, burning, or weakness.
-MC: Chronic axonal polyneuropathies (eg, DM or uremia)
-Axon Length Injury: longer axons are affected first, resulting in symptoms that begin in the LOWER extremities
-Sensory symptoms precede motor symptoms
-Slowly progressive sensory loss and dysesthesias such as numbness, a burning sensation and pain in the feet, and mild gait abnormalities.
-As the syndrome progresses, mild weakness of the lower legs and hand symptoms may begin, resulting in the classic “stocking and glove” distribution of sensory loss.
advanced:
- proximal numbness: affecting the intercostal nerves (the next longest nerve fibers after the arms), sensory loss over the STERNUM
-The top of the head may be affected with further progression
- Damage in distal vessels -> reduced blood flow in the distal arteries which feed the nerves -> nerve damage
Stocking glove loss of sensation
polyneuropathy: axonal neuropathy exam
-Wasting of the intrinsic muscles of the feet or lower leg (late: hands)
-Distal loss of sensation to pin prick, light touch, vibration, cold, and proprioception may also occur.
-Reflexes become hypoactive or absent distally, usually at the ankles initially.
-Early on can be identified w/ detailed sensory examination of the lower extremities
diabetic neuropathy types
Distal symmetric polyneuropathy (MC)
-Classic “glove-stocking” pattern of distal sensory loss
Autonomic neuropathy:
-Diagnosis of exclusion
- sx: postural hypotension, gastroparesis, enteropathy (Diarrhea or Constipation)
Polyradiculopathies: multiple nerve roots damaged, distribution along dermatomes
-Diabetes frequently injures the NERVE ROOTS at thoracic or high lumbar regions -> axonal degeneration
- common features: older, have coexisting peripheral polyneuropathy, and have WEAKNESS and ATROPHY in the distribution of one or more contiguous nerve roots with frequent territorial expansion
Focal mononeuropathies:
-Cranial mononeuropathies: MC is CN III (oculomotor palsy)
-Peripheral mononeuropathies: MC is carpal tunnel syndrome
mononeuropathy multiplex:
- Asymmetric involvement of multiple peripheral nerves
oculomotor nerve palsy
-Oculomotor nerve palsies often present with ptosis and a “down and out eye”
-Is it an “ischemic” or “medical” 3rd nerve palsy (3NP)?
-Dilated and nonreactive: indicates a space-occupying lesion/posterior communicating artery aneurysm compressing CNIII (due to compression of external parasympathetic fibers)
-Spared pupil indicates ischemic/inflammatory VASCULOPATHY: pupillary fibers run externally on nerve and have more collateral blood supply, making them less susceptible to ischemia than central nerve fibers
-Consider microvascular vasculopathy from DM (this will usually be painful)
test for nerve entrapment neuropathy
-Test sensation of the nerves:
-INDEX FINGERPAD = Median nerve
-DORSAL WEBSPACE OF THUMB/INDEX = Radial nerve
-PINKY FINGERPAD = Ulnar nerve
tinel’s test
+ if shooting, aching, worsening numbness with repeated tapping
Try to reproduce numbness and tingling -> 60% sensitive, still used test
cubital tunnel: def, sx, test
Ulnar nerve mononeuropathy - fingerpad of pinky
Symptoms:
- numbness and tingling of the ulnar side of the hand, decreased grip strength
-SEVERE: Clawing deformity of 4th and 5th digits
Tinel test: Tap the ulnar nerve over the medial epicondylar groove to reproduce symptoms of paresthesias
saturday night palsy findings
Radial nerve palsy from compression in the axilla from sleeping on a chair (alcohol), crutch use, or “honeymoon” palsy
EXAM:
- Weakness causing WRIST DROP (inability to extend the finger, thumb, wrist) and numbness over the 1st dorsal interosseous
phalen maneuver
