Weakness

Question 0

Neuromuscular junction disorders – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 0

Fluctuating weakness (may change from hour to hour)

Some autonomic dysfunction but no sensory signs

#EMG/NCS
#Specific serum markers if indicated (antibodies)

#Myasthenia gravis
#Lambert-Eaton syndrome

Question 1

Primary muscle disorders – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 1

Symmetric Weakness in the proximal muscles and NECK (neck not affected in most nerves or brain lesions)

#Muscle pain if inflammatory (polymyositis)
#Reflexes preserved (unless those paralyzed)

#Creatinine kinase
#EMG

Acquired (myopathies from inflammation or toxins) versus congenital (muscular dystrophy)

Question 2

Peripheral nerve disorders – patterns of weakness? Associated Signs and symptoms? What labs to order?

Answer 2

#Mononeuropathy – affects single peripheral nerve
#Mononeuropathy multiplex – multiple peripheral nerves in succession
#Polyneuropathy – all peripheral nerves

Numbness, tingling, pain, absent reflexes

EMG/NCS

Question 3

Types of peripheral nerve disorders and examples?

Answer 3

Mononeuropathy – entrapment (carpal tunnel syndrome)

Polyneuropathies – multiple causes

Question 4

Nerve root disorders – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 4

Radiculopathy or polyradiculopathy

Tingling, radiating pain

#MRI/NCS
#if single radiculopathy MRI to rule out structural lesion
#If polyradiculopathy , LP to rule out infection/inflammatory condition

#if single radiculopathy herniated disc or shingles
#If polyradiculopathy , infectious/inflammatory etiology

Question 5

Plexus disorder – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 5

Multiple muscles in a limb are weak and lesions do not conform to pattern of particular nerve root

Associated sensory findings or trapped reflexes

#EMG/NCS
#MRI of brachioplexus/pelvis

#Eupeptic information
#Radiation
#Metastases
#Hemorrhage/trauma
#Diabetic amyotrophy (lumbosacral plexopathy)

Question 6

Spinal cord disorders – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 6

#Weakness of muscles affecting anterior horn cells (mimics radiculopathy)
#Weakness below level of lesion (affects corticospinal tracks)

#Sensory findings (interruption of ascending tracks)
#Babinski signs
#bowel/bladder incontinence

#MRI
#LP

#Transverse myelitis
#Infarction
#Compression
#Amyotrophic lateral sclerosis

Question 7

Cerebral hemispheres and brainstem disorder – pattern of weakness? Associated Signs and symptoms? What labs to order? Differential?

Answer 7

#Motor strip
#Internal capsule if arm/leg/face all affected

#Associated cognitive signs
#Left hemispheric – Aphasia or apraxia
#Right hemispheric – neglect Visiospatial dysfunction
#Brainstem – cranial nerve problems

MRI/CT

#Stroke
#Demyelinating disease
#Brain tumor
#Infection