Neurology 4 Flashcards
What scan should you do for an acute neuro presentation (except for spine)? Why?
CT head. Takes 2-3 mins whereas an MRI takes about 40 mins and has more safety issues.
What scan should you do for anything to do with the spine or anything to do with MS?
MRI, even in acute presentations involving the spine e.g. cauda equina
Why is a CT of the spine not very useful?
Doesn’t show discs/nerves/nerve roots etc.
Where does the spinal cord end?
L1/2
What is at the bottom of the spinal cord?
Cauda equina - bundle of nerve roots from the lumbar/sacral levels that branch off the bottom of the spinal cord
What causes cauda equina?
Lumbar disc herniation = most common
Spinal stenosis e.g. degeneration from ankylosing spondylitis
Trauma, tumours, abscesses
How is cauda equina treated?
Surgical decompression ASAP
Treat underlying cause - antibiotics for abscess, chemo for malignancy etc.
How is cauda equina investigated?
MRI spine
How does cauda equina present?
Bowel + bladder dysfunction (incontinence/loss of sphincter control)
Saddle paraesthesia - feels strange sitting/wiping
Bilateral leg weakness/loss of reflexes
Aching back pain with sciatica (radiates down leg)
Sexual dysfunction
What are the 3 cardinal symptoms of brain tumours?
Signs of raised ICP
Progressive focal neurological deficits
Epileptic seizures
What are the less common symptoms of brain tumours?
Constant headache
N+V
Drowsiness
Change in personality/behaviour
Describe the headache seen in a brain tumour.
Often nocturnal, worse on waking, coughing, straining, bending forward and lying down
What are primary brain tumours?
Brain is original site of tumour
Where do primary tumours metastasise to?
Don’t metastasise outside of CNS
What are the types of primary brain tumours?
Gliomas
Meningiomas
Others - pituitary, CN, haematopoietic (lymph cells)
What is the most common primary brain tumour?
Glioma
What is a glioma?
Tumour of the glial cells in the brain/spinal cord e.g. astrocytoma, oligodendroglioma
What is a meningioma?
Tumour growing from cells of the meninges, usually benign
What are secondary brain tumours?
Sites the cancer has spread to i.e. metastases?
What are the most common cancers to metastasise to the brain?
Lung, breast, kidney, GI tract and skin
How do you investigate a brain tumour?
Brain imaging - CT/MRI
Brain biopsy/surgery
How is a brain tumour treated?
Often non-curative
Radio/chemotherapy - limited use
Consider palliative care
What can a glioma progress to?
Glioblastoma when it gets to grade 4 = really bad
When should you suspect a brain tumour when a patient presents with a headache?
New onset headache + history of cancer Cluster headache Seizure Significantly altered consciousness, memory, confusion Papilloedema Other abnormal neuro exam
What are the signs of raised ICP?
Papilloedema
Focal neurological signs
Loss of consciousness
New onset seizures
What are the symptoms of raised ICP?
Headache
Drowsiness
Vomiting
What nerves are affected in a polyneuropathy?
Lots of nerves affected all over body
What nerves are affected in a mononeuropathy?
Just one nerve
How does polyneuropathy present?
Slowly progressive
Sensory symptoms
Motor symptoms e.g. weakness
Trophic changes
What are the sensory symptoms of a polyneuropathy?
Loss of touch/proprioception/pain/temp, paraesthesia
What are the trophic changes in a polyneuropathy?
Dry scaly pigmented skin with ulcers/callouses
What causes polyneuropathy?
Diabetes and CMT disease
How does mononeuropathy present?
Upper limb nerves mostly affected at compression points
Sensory/motor symptoms in dermatome and myotome supplied by nerve
What causes mononeuropathy?
Most common = median nerve entrapment at wrist (CTS)
What are the other peripheral nerve causes of weakness?
Metabolic - B12 deficiency Uraemia Thyroid Alcohol Toxins Drugs Paraneoplastic Guillain Barre
What pattern of neuropathy does vasculitis normally present with?
Asymmetrical sensorimotor, often patchy distribution
How do you investigate neuropathy?
Mostly clinical
Bloods - FBC, U+Es, ESR, glucose, TFTs, LFTs, B12, folate
Vasculitic antibodies if vasculitis suspected e.g. ANA, ANCA, anti-dsDNA, RhF etc.
Nerve conduction studies
How is neuropathy managed?
Neuropathic analgesia options = gabapentin, pregablin, amitriptyline
Treat underlying cause e.g. diabetes control, steroids if vasculitis/inflammatory
How does CTS present?
Pain and parasthesia in thumb, index and middle finger
Wakes people from sleep in morning
Can’t open jars
What nerve is affected in CTS?
Median nerve = C6-T1
What causes CTS?
Entrapped at wrist e.g. sleeping position
How does an ulnar nerve mononeuropathy present?
Pain and parasthesia in little and ring fingers and forearm
What are the nerve roots of the ulnar nerve?
C8-T1
What causes an ulnar nerve mononeuropathy?
Entrapped at cubital tunnel at elbow - elbow fracture/arthritis
How does a common peroneal nerve mononeuropathy present?
Foot drop
Sensory deficit over dorsum of foot
What are the nerve roots of the common peroneal nerve?
L4-S2
What causes a common peroneal nerve mononeuropathy?
Compressed against head of fibula
How does a radial nerve mononeuropathy present?
Can’t extend fingers or wrist > wrist drop
What causes a radial nerve mononeuropathy?
Falls - spiral fracture of humerus
Sitting/sleeping with arm on chair/underneath someone = ‘Saturday night palsy’
What are the nerve roots of the radial nerve?
C5-T1
What is Guillain Barre Syndrome (GBS)?
Demyelinating disease of the PNS
What causes GBS?
Unknown
What triggers GBS?
Usually triggered by infections - bacteria, viruses
What bacteria commonly cause GBS?
Campylobacter jejuni, mycoplasma pneumoniae
What viruses commonly cause GBS?
Cytomegalovirus, EBV
What are the features of GBS?
Progressive onset limb weakness/paralysis (LMN signs)
Numbness/tingling
CN and autonomic nerves may be involved
How does GBS present?
Ascending pattern - starts distally and spreads proximally
Usually symmetrical
How are the CN involved in GBS?
Diplopia, difficulty speaking, bulbar palsy
How are the autonomic nerves involved in GBS?
Constipation, urinary incontinence etc.
How is GBS diagnosed?
Clinical - tests can be normal in early disease
LP
Nerve conduction tests and EMG studies - shows slowing of motor conduction
What does a LP show for GBS?
CSF shows increase in protein or albumin without raised white cells, normal glucose
What is a key complication of GBS?
Involvement of respiratory muscles > respiratory depression > risk of death
What must be monitored in GBS?
FVC serially (spirometry)
How is GBS treated?
Aimed at reducing symptoms
Supportive therapy - physio, feeding tubes, heparin to prevent DVT
Immunosuppressants - IV IG reduces duration and severity of paralysis
Plasmapheresis
What is plasmapheresis?
Plasma filtered to eliminate bad antibodies
What is the prognosis for GBS?
Slowly recover over weeks-months as there is regrowth of myelin
20% have permanent neurological damage
What happens in a CNIII palsy?
Loss of motor function to extraocular muscles (except superior oblique and lateral rectus) + parasympathetic supply responsible for pupillary constriction
How does CNIII palsy present?
Down and out appearance
Ptosis
Mydriasis
What is Horner’s syndrome?
Damage to sympathetic nerves of face
How does Horner’s syndrome present?
Unilateral
Miosis - constricted pupil
Anhidrosis - loss of sweating
Partial ptosis - dropping upper eyelid
How does Bell’s palsy present?
Ipsilateral LMN facial weakness e.g. inability to wrinkle brow, close eye, asymmetrical smile, drooping mouth
Hyperacusis (hypersensitivity to sound)
What nerve is affected in Bell’s palsy?
CN VII
What does CNVII innervate?
Muscles of facial expression and stapedius muscle + taste to anterior 2/3 of tongue
How does a LMN facial nerve lesion present?
E.g. Bell’s palsy
Upper and lower facial paralysis
How does a UMN facial nerve lesion present?
E.g. stroke
Lower facial paralysis only - forehead is spared
What does CNIV do?
Innervates superior oblique
Medial rotation, depression and abduction
What does CNVI do?
Lateral rectus
Abducts the eye (ABducens ABducts)
Why is the eye down and out in CNIII palsy?
Unopposed action of superior oblique and lateral rectus muscles
Why is there ptosis in CNIII palsy?
Loss of innervation to levator palpebrae superioris
Why is there mydriasis in in CNIII palsy?
Loss of parasympathetic fibres that innervate the sphincter pupillae muscle
What is the pathophysiology of myasthenia gravis?
Disorder of neuromuscular transmission due to binding of autoantibodies (anti-AChR and anti-MuSK) to the Ach receptor at NMJs.
What does myasthenia gravis have a strong link with?
Thymus is abnormal in majority - strong link with thymoma
How is myasthenia gravis investigated?
Bloods - serum anti-AChR/anti-MuSK
CT thymus
Crushed ice test
EMG
What is the crushed ice test?
Ice applied to ptosis for few mins > if ptosis improves = indicative of MG
What does an EMG show for MG?
Decremental muscle response to repetitive stimulation
How does MG present?
Muscle weakness that get worse with use and improve with rest = fatigueability, especially with repetitive movements
No sensory symptoms
What muscles are most affected in MG?
Proximal muscles + muscles of head/neck/eyes most affected
What are the symptoms of MG?
Diplopia Ptosis Myasthenic snarl on smiling (outer corners of lips don't elevate) Weakness in facial movements Difficulty swallowing Dysarthria
How is MG managed?
Acetylcholinesterase inhibitors e.g. pyridostigmine = 1st line
Steroids/immunosuppressants
Consider thymectomy
What is the main complication of MG?
Myasthenic crisis
What is myasthenic crisis?
Acute worsening of symptoms often triggered by another illness
What can myasthenic crisis lead to?
Can lead to respiratory failure due to weakness of respiratory muscles > do an FVC
How is myasthenic crisis treated?
May require ventilation/intubation
Treat with immunomodulatory therapies (IV Ig) and plasma exchange
What causes Lambert-Eaton syndrome?
Paraneoplastic - especially small cell lung cancer
Autoimmune - antibodies against voltage gated calcium channels in presynaptic membranes > defective Ach release
How does Lambert-Eaton syndrome present?
Weakness
Autonomic involvement e.g. dry mouth, incontinence
How do you investigate Lambert-Eaton syndrome?
Serum auto-antibodies
EMG - incremental muscle response to repetitive stimulation (differentiates from MG)
How is Lambert-Eaton syndrome treated?
Treat cancer if present
IV Ig or immunosuppressants
Symptomatic treatment - pyridostigmine
Where does weakness affect in LES?
Proximal muscles around pelvic girdle +/- shoulder
What does weakness in LES improve with?
Sustained/repeated exercise
What is LES similar to?
MG
Give examples of focal neurological deficit symptoms seen in brain tumours.
Sensory loss, ataxia, speech disturbances
What is pyridostigmine?
Acetylcholinesterase inhibitor
What improves pain in CTS?
Hanging arm over side of bed
Why do people with CTS struggle to open jars?
Wasting of thenar muscles
What part of the hand is not affected in CTS?
Palm
Where do polyneuropathies present?
‘Glove and stocking’ distribution
Often symmetrical, starts in legs
What is the non-medicated treatment for HD?
MDT - physio, OT, SALT
