6 - Common Neurological Disorders 3 Flashcards
What is the pathophysiology of MS?
Chronic autoimmune inflammatory disease of CNS
Demyelination of neurones in CNS (oligodendrocytes damaged) by immune cells. Leads to inflammation and production of plaques (scars).
Plaques are axonal loss so irreversible neurological damage. The deficits depend on where the plaques are
Lesions are disseminated in time and place
What is the epidemiology of MS and some risk factors?
More common in women, up north and middle aged
Risk Factors
- Genetic
- Viral infections (EBV)
- High geographic latitude
- Lack of sun exposure/Vit D
Where are the common sites for plaques in MS?
- Optic nerves: affects 40% during course of disease. Presenting demyelinating event in 20%.
- Spinal cord: affects 50-75% during course of disease
- Brainstem: intranuclear ophthalmoplegia
- Cerebellum: ataxia and gait disturbance
- Juxtacortical white matter (near the cerebral cortex)
- Periventricular white matter (near the ventricular system)
What are the different classifications of MS?
Relapsing-remitting (RRMS):
- 90% of cases
- Exacerbations then remission. May remit to normal level in early disease but then residual damage with each relapse
Primary progressive (PPMS):
- 10-15%
- Sustained progression of disease severity from onset
- No remission but can be times where disease not active
Secondary progressive (SPMS):
- 50% of RRMS will develop this in 15 years
- Gradual sustained progression with periods of relapse but no remission
Clinically Isolated Syndrome
- First episode of suspected MS
- No previous episode of demyelination
- Some never go on to have another episode
What are some clinical manifestations of MS?
Depends on site of plaques, usually monosymptomatic at a time
Visual: optic neuritis, INO, abducens palsy
Motor & coordination: transverse myelitis, cerebellar syndrome, Bell’s, Horner’s, Limb weakness, Incontinence
Sensory & autonomic: LHermitte’s Phenomenon (flexion of neck), Paraesthesia, Pain, Heat sensitivity (Uhthoff phenomenon), Sexual dysfunction, Bladder & bowel dysfunction, Trigeminal neuralgia
Cognitive & psychological: depression and fatigue
What is internuclear opthalmoplegia?
- Disorder of conjugate lateral gaze due to demyelination of the medial longitudinal fasciculus
- MLF connects abducens nucleus complex with contralateral oculomotor nucleus
- If left INO, when looking to the right, the right eye will abduct but the left will remain central (failure in adduction). There is also nystagmus
Patients may present with double vision due to lesions with the sixth cranial nerve (abducens nerve). There are two key phrases to remember to describe a sixth cranial nerve palsy: internuclear ophthalmoplegia and conjugate lateral gaze disorder.
Unilateral lesions in the sixth nerve causes a condition called internuclear ophthalmoplegia. Internuclear refers to the nerve fibres that connect between the cranial nerve nuclei that control eye movements (3rd, 4th and 6th cranial nerve nuclei). The internuclear nerve fibres are responsible for coordinating the eye movements to ensure the eyes move together. Ophthalmoplegia means a problem with the muscles around the eye.
Lesions in the sixth cranial nerve cause a conjugate lateral gaze disorder. Conjugate means connected. Lateral gaze is where both eyes move together to look laterally to the left or right. It is disordered in a sixth cranial nerve palsy. When looking laterally in the direction of the affected eye, the affected eye will not be able to abduct. For example, in a lesion affecting the left eye, when looking to the left, the right eye will adduct (move towards the nose) and the left eye will remain in the middle as the muscle responsible for making it move laterally is not functioning.
What is transverse myelitis and cerebellar syndrome that can be a manifestation of MS?
Transverse myelitis: focal inflammation within the spine. Characterised by sensory and motor symptoms below the level of the lesion (e.g. paraesthesia, weakness). Bladder/bowel involvement may be present and usually there is a sensory level that corresponds to the level of the lesion.
Must exclude compressive pathology in first instance (i.e. metastatic cord compression).
Cerebellar syndrome: disease of the cerebellum, which manifests with ataxia, slurred speech, intension tremor, nystagmus, vertigo and clumsiness.
What are 6 MS eponyms?
How is the diagnosis of MS made?
Clincal + MRI for lesion dessiminated in time and space
Revised Mcdonald Criteria
Early treatment reduces relapses and disability so refer to neurology ASAP
What is the definition of a single MS attack and why is an MRI used to aid diagnosis?
- Attack must last >24h with or without recovery and >30d between attacks
- MRI used to look for plaques to prove dissemination in time
- MRI can also prove dissemination in time by gadolinium-enhancing and nonenhancing lesions at any time, or by a new gadolinium-enhancing lesion(s) on follow-up MRI
What are some differentials for MS?
Depends on site of plaque
What is Neuromyelitis optica (Devic’s disease)?
MS variant with transverse myelitis (loss of motor, sensory, autonomic, reflex and sphincters below level of lesion), and bilateral optic neuritis
Associated with Anti-Aquaporin 4 antibodies
What investigations should you do if you suspect MS?
- MRI
- LP (Immunoelectrophoresis of CSF): CSF-specific IgG oligoclonal bands present in CSF but not in serum
- Visual evoked response (VER): measuring electrical activity via transducer over occipital cortex in response to light stimulus. Not for acute but can show previous asymptomatic optic neuritis
- Antibody levels: AQP4 and myelin oligodendrocyte glycoprotein (MOG) associated Neuromyelitis Optica not MS
What bloods should you take if you suspect MS and why?
What are the principles of management in MS?
- General Care
- Managing acute relapses
- Disease modifying therapies
What general care measures are put in place for people with MS?
- Avoid stress
- Spasticity: baclofen or gabapentin, physio
- Tremor: botuline A toxin
- Bladder dysfunction: self catheterisation if residual >100ml, tolterodine if residual <100ml
- Depression: SSRI, CBT
- Fatigue: exercise, CBT
- Neuropathic Pain: amitriptyline, gabapentin or pregabalin.
How is an acute relapse in MS managed?
- PO methylprednisolone 0.5 g daily for five days, OR Intravenous methylprednisolone 1 g daily for 3-5 days
- PPI
- Only use steroids twice a year as don’t alter course of disease just help symptoms
What are some disease modifying treatments used in MS?
Aim to decrease the number of relapses and slow disease progression
RRMS (1ST Line):
- Natalizumab
- Interferon beta
- Teriflunomide
- Alemtuzumab
When should people with MS be offered disease modifying drugs?
What is the prognosis with MS?
Highly variable
- Disease type: RRMS better prognosis than PPMS. Most patients with RRMS eventually develop SPMS.
- Recovery following first attack: incomplete recovery worse prognosis
- Clinical manifestations at onset: motor symptoms (poor prognosis). sensory symptoms, optic neuritis (favourable prognosis).
- Pregnancy: protective during pregnancy. Increased risk of relapse in postpartum period.
- Imaging: lesion load and cerebral atrophy linked to prognosis
How can a relapse of MS be recognised?
What is the main finding on examination with optic neuritis?
- Pain on eye movement
- RAPD
How may pregnancy affect MS?
- Progression halts and no relapses whilst pregnant
- High rate of relapse 3-6months after birth
What are the clinical features of an essential tremor?
Autosomal dominant movement disorder: younger age of onset if inherited
- Postural or kinetic: made worse on arms outstretched
- Usually affects upper limbs, head, lower limbs, face, trunk
- Tremor amplitude increases with time, and patients experience difficulty in writing, eating, holding objects and doing fine motor tasks, dressing, and speaking
What factors can make a benign essential tremor worse and better?
Worse: tired, stress, caffeine, anxiety
Better: alcohol, sleep
What are some differentials for a benign essential tremor?
- Parkinson’s disease (no bradykinesia in BET)
- Multiple sclerosis
- Huntington’s Chorea
- Hyperthyroidism
- Fever
- Medications (e.g. antipsychotics)
How is a benign essential tremor managed?
No cure just symptomatic treatment if affecting functionality:
- Behavioural techniques and physical therapy
- Medical: propranolol, primidone (barbiturate AED)
- Surgical: deep brain stimulation, focused ultrasound thalamotomy
What is a radiculopathy?
Compression of the nerve roots as they exit the spinal cord, leading to motor and sensory symptoms
Dermatome and Myotome loss
How may a radiculopathy (nerve root compression) present and what are some causes of a radiculopathy?
- Pain/Electrical sensation in arms or fingers at level of compression
- LMN weakness, dull reflexes, wasting of the muscles innervated by nerve root
- Causes: disc herniation, cervical spondylosis
Fill out this table for cervical radiculopathies C4 to T1?
ddd
Fill out this table for the lumbar radiculopathies L3 to S1.
What are the nerve roots, symptoms and causes of the following mononeuropathies?
- Radial Nerve
- Brachial Plexus
- Phrenic Nerve
What are the nerve roots, symptoms and causes of the following mononeuropathies?
- Lateral Cutaneous Nerve of the Thigh
- Sciatic nerve
- Common Peroneal Nerve
- Tibial Nerve
What is mononeuritis multiplex and what are the causes of this?
Type of peripheral neuropathy that causes sequential peripheral nerves to become involved both sensory and motor
Hard to distinguish from polyneuropathy as it progresses as becomes symmetrical
Can cause deep pain at night
DM mononeuritis multiplex: acute, unilateral, severe thigh pain followed by anterior muscle weakness and loss of knee reflex
How may an ulnar mononeuropathy present and what are some of the causes of this?
- Weakness of the intrinsic muscles of the hand: ‘claw hand’, flexion of 4th and 5th DIP
- Finger weakness in both abduction and adduction
- Sensory loss over fifth digit
- Froment’s sign positive: flexion of thumb when due to weak adductor pollicis
- Unable to cross their fingers in a ‘good luck’ sign
- Hypothenar and Interossei wasting
Causes (Cubital Tunnel and Guyon’s Canal): fracture, dislocations, laceration, diabetes
What is the ulnar paradox?
Greater clawing in the hand when lesion at the wrist compared to the elbow.
Higher lesions will cause weakness of flexor digitorum profundus, hence an inability to flex the digits
How are ulnar nerve mononeuropathies treated?
- Rest and avoid pressure on the nerve
- Soft elbow splinting at night
- Splint hand to prevent permanent clawing
- Surgery: decompression, medial epicondylectomy, nerve re-routing
What are some causes of carpal tunnel syndrome?
Anything causing swelling or compression in wrists
- Pregnancy
- Diabetes
- Hypothyroidism
- Radial fracture
- Acromegaly
- Ganglion or Lipoma
- RA
- Pregnancy
- Sarcoidosis
What is carpal tunnel syndrome and what are the clinical features of this?
Compression of the median nerve in carpal tunnel
- Tingling/pain in the first three digits, worse at night and relieved by shaking/ hanging out the hand at night
- Wasting of thenar eminence
What are the functions and path of the facial nerve?
Nucleus in the pons, cerebellopontine angle. Passes through internal acoustic canal within the temporal bone in close proximity to the inner ear. Then enters the facial canal then exits the skull via the stylomastoid foramen. It terminates into five terminal motor branches within the parotid gland
Motor: Nerve to stapedius, Posterior auricular nerve, nerve to the posterior belly of the digastric muscle, nerve to the stylohyoid muscle, TZBMC
Sensory: Taste to anterior ⅔ third
Parasympathetic: greater petrosal nerve (lacrimal gland), chordates tympani (sublingual/submandibular glands)
What are some causes of facial nerve palsy?
- Bell’s
- Inner ear disease (Otitis media, cholesteatoma)
- Parotid disease (Parotid tumour, parotitis)
- Sarcoidosis
- Guillain-Barré syndrome
- Trauma
- Stroke
- Tumours
- Encephalitis
- Meningitis
- Multiple sclerosis
- Diabetes mellitus related neuropathy
What are the signs and symptoms of Bell’s palsy?
Rapid onset (< 72 hours) of unilateral facial weakness
Idiopathic facial nerve palsy thought to be linked to autoimmunity or viral causes
How can we grade acute facial paralysis?
House-Brackmann system
How is Bell’s palsy diagnosed?
Clinical diagnosis based on unilateral facial weakness, of rapid onset, without forehead sparing
May want to do routine blood tests, lyme serology, HIV test!!!
How is Bell’s Palsy managed?
Supportive: Reassure prognosis good but may take few months to recover, use straw to drink
Medical: if present within first 72 hours PO Prednisolone and consider PO Aciclovir in case Ramsey Hunt syndrome
Eye care: Lubricating drops, wear sunglasses outdoors, tape eye when sleeping, House Brackmann 4 or more refer to Optho
ALWAYS LOOK IN THE EARS
What are some complications with Bell’s Palsy?
Usually takes 4 months to recover
- Corneal Ulcer
- May not recover if no improvement in three weeks
- Aberrant reinnervation (Marcus-Gun Jaw winking): voluntary muscle contraction leading to involuntary contraction of another muscle
What is cervical spondylosis?
Age related osteo-degeneration of the cervical spine that can range from asymptomatic to myelopathy and spastic quadriparxsis
What is the pathophysiology of cervical spondylosis?
Degeneration of the annulus fibrosis, osteophyte formation and facet joint hypertrophy leads to narrowing of spinal canal and intervertebral foramina
As the neck flexes and extends the spinal cord is dragged along bony spurs and thickened ligamentum flavour posteriorly
What are some of the presenting symptoms of cervical spondylosis?
Symptoms
- Neck pain and stiffness with crepitus and limited movement
- Stabbing or dull arm pain
- Forearm/Wrist pain
- Radiculopathy: due to compression of nerve roots at the site of foraminal exit
- Myelopathy: due to dynamic stretch of spinal cord over impinging spinal osteophytes
What signs may you elicit on examination of a person with cervical spondylosis?
- L’Hermitte’s Phenomenon: Tingling down spine on neck flexion
- Flaccid upper limb paresis: Due to radiculopathy
Bowel and bladder disturbance rare
What are two complications of cervical spondylosis and how will they present?
Radiculopathy (Root Compression): Electrical sensation/pain in arms and fingers at level of compression, LMN weakness, dull reflexes
Spinal Cord Compression: Progressive symptoms (increasing weak clumsy hands, gait disturbance), UMN leg signs, LMN arm signs, incontinence, hesitancy, urgency
How is cervical spondylosis managed?
- Red Flags (Cord Compression): Urgent MRI
- Analgesia
- Encourage gentle activity/physio
- Cervical collars: use for brief periods but prolong symptoms so try to avoid
- MRI: if no improvement in 4-6 weeks
- Neurosurgical referral: interlaminar cervical epidural injections, discectomy, laminectomy
How may lumbar spondylosis present?
- Asymptomatic
- Lower back pain
- Sciatica
Do same investigations and management as cervical spondylosis
What are the different types of diabetic neuropathy?
Peripheral neuropathies due to chronic hyperglycaemia
- Symmetric sensory polyneuropathy
- Mononeuritis multiplex
- Amyotrophy
- Autonomic neuropathy
- Small-fibre Predominant Neuropathy
What is the most common diabetic peripheral neuropathy, how does it present and how is it treated?
Distal Symmetrical Sensory Polyneuropathy
Presentation:
- Glove and stocking numbness/tingling/pain. Pain is worse at night
- Affects touch, vibration, proprioception
- Loss of reflexes
Rx:
- Paracetamol → Amitriptylline → Duloxetine/Pregablin/Gabapentin → Opiates
- Avoid weight bearing
How may Small-fibre Predominant Diabetic Neuropathy present?
- Caused by loss of small sensory fibres.
- Deficits in pain and temperature sensation in a glove and stocking distribution
- Episodes of burning pain.
What is diabetic amyotrophy and how may it present?
- Inflammation of lumbosacral plexus or cervical plexus
- Severe pain around the thighs and hips
- Proximal weakness and wasting of quadriceps
How may diabetic autonomic neuropathy present?
- Postural hypotension
- Gastroparesis (early sateity, nausea, vomiting)
- Urine retention
- Erectile dysfunction
- Gustatory sweating
- Diarrhoea
- Arrhythmias
How can gastroparesis and postural hypotension due to autonomic neuropathy be managed?
Gastroparesis
- Diagnosed by gastric schintigraphy with Te99
- Antiemetic (Metoclopramide), Erythromycin, Gastric Pacing
Postural Hypotension
- Fludrocortisone
- Midocrine (a-agonist)
Apart from diabetes, what are some other causes of autonomic neuropathy?
- Infections (HIV, lyme and chagas)
- Autoimmune disease (SLE)
- Amyloidosis
- GBS
- Drug induced (antihypertensives, anticholinergics)
- Primary autonomic failure
- Paraneoplastic syndromes
What is primary autonomic failure?
Can be autoimmune OR as part of multi system atrophy (MSA) OR with Parkinson’s
Insidious onset
