Neuropathies Flashcards
What is syringomyelia(syrinx)
Syringomyelia (‘syrinx’ for short) describes a collection of cerebrospinal fluid within the spinal cord.
Causes of syringomyelia
A chiari malformation(strong association)
Trauma
Tumours
Idiopathic
Classical presentation of a syrinx
‘Cape-like’(neck and arms) loss of sensation to temperature but preservation of light touch, proprioception and vibration.
Other symptoms and signs include spastic weakness (predominantly of the upper limbs), paraesthesia, neuropathic pain, upgoing plantars and bowel and bladder dysfunction
What might a syrinx cause if untreated
Scoliosis over a matter of years
May cause hornet’s syndrome due to compression of sympathetic chain but this is rare
Function of CNIII
Eye movement (MR, IO, SR, IR)
Pupil constriction
Accomodation
Eyelid opening
Presentation of CNIII palsy
ptosis
‘down and out’ eye
dilated, fixed pupil
Function of CNIV
Eye movement (SO)
Presentation of CNIV palsy
Palsy results in defective downward gaze → vertical diplopia
Function of CNV
Facial sensation
Mastication
Presentation of trigeminal nerve lesions
trigeminal neuralgia loss of corneal reflex (afferent) loss of facial sensation paralysis of mastication muscles deviation of jaw to weak side
Function of CNVI
Eye movement (LR)
Presentation of CNVI palsy
Palsy results in defective abduction → horizontal diplopia
Function of CNVII
Facial movement
Taste (anterior 2/3rds of tongue)
Lacrimation
Salivation
Presentation of CNVII lesions
flaccid paralysis of upper + lower face
loss of corneal reflex (efferent)
loss of taste
hyperacusis
Function of CNVIII
Hearing
Balance
Presentation of CNVIII palsy
Hearing loss
Vertigo, nystagmus
Acoustic neuromas are Schwann cell tumours of the cochlear nerve
Function of CNIX
Taste (posterior 1/3rd of tongue)
Salivation
Swallowing
Mediates input from carotid body & sinus
Presentation of CNIX lesions
Lesions may result in;
hypersensitive carotid sinus reflex
loss of gag reflex (afferent)
Function of CNX
Phonation
Swallowing
Innervates viscera
Presentation of CNX lesions
Lesions may result in;
uvula deviates away from site of lesion
loss of gag reflex (efferent)
Function of CNXI
Head and shoulder movement
Presentation of CNXI lesions
Lesions may result in;
weakness turning head to contralateral side
Function of CNXII
Tongue movement
Presentation of CNXII palsy
Tongue deviates towards side of lesion
Corneal reflex - afferent and efferent limb
Aff - Ophthalmic(v1)
Eff - Facial
Jaw jerk reflex - aff and eff limb
Aff - Mandibular nerve(V3)
Eff - Mandibular nerve(V3)
Gag reflex - nerve limbs
Aff - IX
Eff - X
Carotid sinus reflex - nerve limbs
Aff - IX
Eff - X
Pupillary light reflex - nerve limbs
Aff - II
Eff - III
Lacrimation - nerve limbs
Aff - V1
Eff - VII
What is a benign essential tremor
Associated with older age
Characterised by fine tremor affecting all voluntary muscles(most notable in hands)
Features of benign essential tremor
Fine tremor Symmetrical More prominent on voluntary movement Worse when tired, stressed or after caffeine Improved by alcohol Absent during sleep
Causes of tremor
Parkinson’s disease Multiple sclerosis Huntington’s Chorea Hyperthyroidism Fever Medications (e.g. antipsychotics)
Mx of benign essential tremor
Does not need treatment if not causing functional or psychological problems
Propranolol (a non-selective beta blocker)
Primidone (a barbiturate anti-epileptic medication)
Typical features of neuropathic pain
Burning Tingling Pins and needles Electric shocks Loss of sensation to touch of the affected area
Questionnaire used to assess neuropathic pain
DN4 questionnaire
They are then scored out of 10 for their pain. A score of 4 or more indicates neuropathic pain.
Mx of neuropathic pain
Amitriptyline
Duloxetine
Gabapentin
Pregabalin
1st line mx of neuropathic pain in trigeminal neuralgia
Carbamazepine
Other options for mx of neuropathic pain
Tramadol ONLY as a rescue for short term control of flares
Capsaicin cream (chilli pepper cream) for localised areas of pain
Physiotherapy
Psychological input
What is complex regional pain syndrome
Areas are affected by abnormal nerve functioning causing neuropathic pain and abnormal sensations. It is usually isolated to one limb.
Often it is triggered by an injury to the area.
Presentation of complex regional pain syndrome
The area can become very painful and hypersensitive even to simple inputs such as wearing clothing. It can also intermittently swell, change colour, change temperature, flush with blood and have abnormal sweating.
Mx of complex regional pain syndrome
Treatment is often guided by a pain specialist and is similar to other neuropathic pain.
Effects of radial nerve damage
Wrist drop
Sensory loss to small area between dorsal aspect of the 1st and 2nd metacarpals
paralysis of triceps
Effects of median nerve damage
paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand deformity)
sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
unable to pronate forearm
weak wrist flexion
ulnar deviation of wrist
Median nerve root
median nerve is formed by the union of a lateral and medial root respectively from the lateral (C5,6,7) and medial (C8 and T1)
Radial nerve root
C5-T1
Common peroneal nerve root
L4-S2
Features of common perineal nerve lesion
Foot drop
weakness of foot dorsiflexion
weakness of foot eversion
weakness of extensor hallucis longus
sensory loss over the dorsum of the foot and the lower lateral part of the leg
wasting of the anterior tibial and peroneal muscles
