see also: [[Numbness]], [[peripheral nerve disorders]], [[Cranial nerve palsies]] see: [Cameron - Weakness](x-devonthink-item://36213A49-C74D-4AAE-8F1C-3F10C2D3D9D9?page=429), [Rosen - spinal cord disorders](x-devonthink-item://E503214B-122B-434B-87D4-F04631F3A011?page=5&start=2352&length=26&search=SPECIFIC%20DISEASE%20PROCESSES), [Rosen Brain and cranial nerve disorders](x-devonthink-item://7CFC3D01-37EB-4CA6-A1E0-847AC54CADD8?page=4), [Rosen Peropheral nerve disorders](x-devonthink-item://86D59A3D-CC1E-49AC-A7E9-F75C6FD27044?page=2) #tables # DDx - neurological - [[Guillain-Barré syndrome]] - [[myasthena gravis]] - [[Multiple Sclerosis]] - myopathies - muscular dystrophy - acquired - metabolic/electrolyte - [[hypokalemia|hypokalaemic]] periodic paralysis - [[thyrotoxicosis]] - [[Adrenal insufficiency|Addison's disease]] - statins - corticosteroids - [[Cushing's disease]] - Intoxications - [[Botulism]] - tetanus - tick paralysis - [[organophosphates]] - [[Cholinergic syndrome|cholinergic crisis]] - [[Marine Envenomation]] - puffer fish - blue-ringed octopus - extrinsic lesions - spinal epidural haematoma -- sudden severe radicular back pain usually present prior to onset of deficits. tx decompressive lainectomy - spinal epidural abscess-- classically febrile with progressive neuroloical deficits - discitis -- children with back pain at level of lesion **Mnemonic**: [[peripheral nerve disorders]]: Toxin-MANIC - Toxins (e.g. tick paralysis, heavy metal) - Metabolic (diabetes) - Autoimmune (GBS, CIDP) - Nutritional (B12) - Infectious (VZV/shingles/lyme) - Compression (CTS) | Cause | reflexes | Sensation | characteristics | Ix | Tx | | ------------------------------------------------------ | ------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------- | | [[Guillain-Barré syndrome\|GBS]] | ↓ or absent deep tendon reflexes | - normal or reduced | - symmetrical ascending flaccid weakness<br>- facial palsy<br>+/- autonomic dysfunction<br> | - LP<br>- CSF ↑ protein, normal/low WCC<br>- do serial resp assessments of [[FVC\|Forced vital capacity]] to predict intubation (<12 mL/kg) | - IVIG 2 g/kg<br>- plasmaphoresis<br>- no steroids | | spinal cord compression /<br>[[cauda equina syndrome]] | ↑ hyperreflexia | ↓ reduced below level of injury | - "Red Flags"<br>- fever, malignancy, IVDU warrant MRI | - MRI | - decompression<br>- abx if infection<br>- radiotherapy if malignancy | | [[myasthena gravis]] | normal | normal | - fluctuating, fatigable weakness of voluntary muscles<br>- especially ocular or proximal limbs<br>- ptosis<br>- improves with rest<br>- improvement of ptosis after edrophonium administration<br>- resp involvement if severe | | - anticholinesterase tx<br>- no steroids (may exacerbate condition)<br>- IVIG 2g/kg<br>- plasmapheresis | | [[Multiple Sclerosis]] | tend to be UMN sigs (hyperreflexia) | | - variable weakness<br>- hypertonicity, spasticity, clonus<br>- altered pain, temp, vibration, and proprioception<br>- Lhermitte sign (electric shock elicited by neck flexion) <br>- optic neuritis with acute central vision loss, afferent pupillary defect<br>- internuclear opthalmoplegia<br>- cerebellar signs | - MRI with white matter lesions or homogeneous periventricular lesions on T2-weighted MRI of brain / spinal cord <br>- CSF - elevated protein and gammaglobulins (oligocloncal bands) and pleuocytosis with mild lymphocytosis | - methylprednisolone for exacerbations<br>- long term DMARDs<br>- vitamin D | | Transverse myelitis | initially absent, then hyperreflexia<br>- clonus<br>- babinski response<br>- anal sphincter dysfunction | ↓ below level of defect | - inflammation of spinal cord a/w prior viral infection<br>- paraplegia and defined sensory level impairment<br>- sphincter disturbance<br>- autonomic dysfunction (hyper/hypotension, tachycardia or bradycardia)<br>- DDx is MS, spinal epidural abscess or haematoma, neoplasm, spinal cord infarct, surfer's myelopathy, B4 def | MRI | +/- glucocorticoids | | Spinal cord infarction | Usually ↓ deep tendon reflexes | - usually reduced; but may have only posterior (proprioception and vibration) or anterior (more common; motor, pain, and temperature) deficits | - Distribution of affected artery may follow classical [[Cervical spine trauma radiology#Spinal cord syndromes\|spinal cord syndromes]]<br>- Usually presents with pain<br>- Anterior spinal artery syndrome is most common: loss of motor function and pain/temperature sensation, with relative sparing of proprioception and vibratory sense below the level of lesion<br>- usually presents with flacid paralysis<br>- Posterior spinal artery syndrome: loss of proprioception and vibratory sense below the level of the injury and total anesthesia at the level of injury; weakness usually mild/transient<br>- look for evidence of [[Aortic dissection]] or thoracic aneurysm, embolic risks | MRI | See [wikipedia - spinal stroke](https://en.m.wikipedia.org/wiki/Spinal_cord_stroke) | - hypo-K - myopathies (inflammatory myositis/dermatomyositis - pain, ↑CK - exam: rash, painful, proximal > distal | feature | GBS | Myasthena Gravis | motor neuron disease | | ------------------------ | ----------------------------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------- | | distribution of weakness | ascending and symmetrical flacid weakness | eyes and cranial nerves<br>proximal limbs, ptosis | asymmetrical<br>distal limbs; usually starts in fingers | | progression | acute then recovery | relapsing | gradual progression distal → proximal | | fatigue | no | worsens with fatigue and repetition<br>can be worse in afternoon and better in morning | not fatigable | | fasiculation | no | no | yes | # weakness ddx table | area | ddx | | --------------------- | -------------------------------------------------------------------------------- | | muscle | - polymyositis<br>- dermatomyositis<br>- statin myopathy<br>- [[rhabdomyolysis]] | | myelopathy | - transverse myelitis<br>- cord compression | | metabolic | - [[hypokalemia]] (eg periodic paralysis) | | NMJ | - myasthenia gravis<br>- toxin: snake, tick<br>- eaton lambert<br>- botulism | | peripheral neuropathy | - [[Guillain-Barré syndrome\|GBS]] | # Patterns of peripheral neuropathies table | pattern of distribution | prototypical disease | | ------------------------------------------------------------------------------ | -------------------------------- | | proximal and distal, symmetrical, sensormotor polyneuropathy. Motor > sensory | [[Guillain-Barré syndrome\|GBS]] | | distal, symmetrical, sensorimotor polyneuropathy. sensory > motor | diabetic sensory polyneuropathy | | distal, asymmetrical, pure motor neuronopathy | ALS | # unilateral facial weakness ddx | aeteology | differentials | | ---------- | -------------------------------------------------------------------------------------------------------------------------------------- | | cerebral | CVA, GBS, MS, CVST. +/- carotid dissection | | ear | acute or chronic otitis media, necrotising otitis externa, cholesteatoma, schwannoma | | infectious | HZV ([[Herpes zoster#Ramsey Hunt syndrome\|Ramsay Hunt Syndrome]], mumps, rubella, EBV. bell's palsy | | neoplastic | primary cerebral malignancy (GBM or astrocytoma), cutaneous malignancy of the face or neck, parotid tumour, lymphoma of cervical chain |