NEURO: Part 8 Flashcards
What is Uhtoff’s phenomenon
A worsening of symptoms due to exposure to higher the n normal temperature - MS
What is Lhermitte’s sign
In MS, an electrical sensation that runs down the back when bending the neck - CHARACTERISTIC of MS
What factors increase risks of relapses in MS
COLD
Influenza
Gastroenteritis
Biomarkers for MS
- Oligoclonal bands (found in lumbar puncture - proteins present in the CNS but not the blood)
Signs of Myasthenia Gravis in the eyes
MUSCLES OF EYES AFFECTED INITIALLY:
- ptosis - levator palpeerde superioris
- diplopia - due to weakness of extra ocular muscles
- Symptoms worsen when watching television, reading or driving in bright conditions
Isolated symptoms to eye is called ocular myasthenia graves
Signs of Myasthenia Gravis when eating
- DYSPHAGIA (weakness of oesophageal muscles)
- Weakness of muscles of mastication
- Velopharyngeal insufficiency (regurgitation of food and liquids into nose than down the throat)
Signs of myasthenia graves when speaking
- Dysarthria
2. Hypophonia and nasal quality
Signs of myasthenia graves in the fcae
Weakness of facial expression muscles: Can’t keep mouth closed, dropping eye lids
THEY LOOK SAD
What is a dangerous red sign of myasthenia graves
Muscles that control breathing - dyspnea and limb movement is affected = takes years to occur
Results in myasthenic crisis
What is myasthenic crisis
When paralysis of res muscles occur
Pathophysiology of myasthenia graves
- Antibodies produced against nicotinic cholingeric receptor or muscle-specific kinase
- Deposition of complex anti-ACHr IgG and complement at post-synaptic membranes = destruction of receptors
What condition is MG in females associated with
THYMIC HYPERPLASIA
RA
SLE
pernicious anaemia
What conditions are associated in males with MG
THYMIC ATROPHY?TUMOUR
RA
SLE
What causes transient MG
D-PENICILLAMINE TREATMENT
WILSON’S DISEASE
Differential diagnosis of MG
- MS
- Hyperthyroidism
- Acute Guillain-Barre syndrome
- Lambert-Eaton myasthenic syndrome
What is Lambert-Eaton syndrome
- Causes defective ACh release at neuromuscular junction but weakness IMPROVES after exercise compared to MG
Physical examination done in MG
- Ask patient o do repetitive movements (allows us to see ptosis)
- Curtain sign : Holds a patient’s eye open which will lead to the other eye closing
FBC in MG
- autoantibody for AChR (not very sensitive in ocular myasthenia gravis)
- If negative, look for MUSK protein antibodies
Diagnostics for MG
- Electromyography
- ICE Test
- Edrophonium test
- CXR / CT/MRI
- Pulmonary function test
What do we look for in EMG for MG
- Repetitive nerve stimulation as muscle fibres are easily fatigued in MG
What do we look for in the ice test
- Apply ice for 4-5 mins to eyelids: ACh esterase is inhibited at lower temperatures
Positive if there is greater than 2mm rise in the eye lid after ice is removed
Role of CXR in myasthenia graves
- Mediastinum widening (thymoma or hyperplasia of thymus)
Role of MR in myasthenia graves
Eliminates lesions of cranial nerves and ocular muscles
Mediastinal widening
How are symptoms of MG controlled
ACh esterase inhibitor
Immunosuppression treatment for MG
- ORAL PREDNISOLONE (increase dose per week)
- Bosphosphonates to stop osteoporosis
- METHOTREXATE or ORAL AZATHIOPRINE if disease becomes more general
Surgical intervention for MG
Thymectomy
When is a thymectomy done
If onset is less than 50 years or poorly controlled with AChesterases
How to treat myasthenic crisis
- PLASMAPHERESIS (antibody removal) and IV immunoglobulin to stop trigger of relapses
Define apraxia
Disorder of consciously organised pattern of movement or impaired ability to recall acquired motor skill
How is movement fine-tuned
- First we think about the idea of movement
- Activate upper motor neurones in pre-central gyrus
- Impulses travel down LMB and motor units via corticospinal tract
- Modulating activity of cerebellum and basal ganglia
- Further modification of movement depending on sensory feedback
What type of motor neurone are LMNs
Alpha motor neurone
How is muscle tone regulated
- Stretch receptor sin the muscle are innervated by gamma motor neurones
- Muscle stretched -> afferent impulse from muscle spindles -> reflex partial contraction of muscle
What are stretch receptors in the muscle called
MUSCLE SPINDLES
Potential sites of damage along motor pathway
- Motor nuclei of cranial nerves
- Motor neurones in spinal cord
- Spinal ventral roots
- Peripheral nerves
- NMJ
- Muscle
Physical examination of UMN signs
- EVERYTHING GOES UP
Brisk reflexes - tension + jaw reflexes
Babinski sign
Limb muscle weakness
What is babinski’s sign
Planters are upturned on stimulation
Physical examination of LMN signs
EVERYTHING GOES DOWN
- Flaccidity
- Muscle wasting
- Fasciculations (needs weakness to diagnose LMN)
- Reflexes absent
What is motor neurone disease
- Cluster of major degenerative diseases characterises by selective loss of neurones in motor cortex, cranial nerve nuclei and anterior horn cells
What is MND called in other countries
ALS
In what gender is MND common in
Males
Age onset of MND
60 years
How can all eyes of MND be differentiated
- Is disease sporadic or inherited
2. Involvement of UMN, LN or both
What is the Hoffmann’s reflex
Loosely hold middle finger and flick fingernail downward allowing middle finger to flick upwards reflexively
(upper limb equivalent to babinski’s sign)
What genetic mutation causes MND
- Mutation in free radical scavenging enzyme superoxide disumtase
Pathophysiology of NMD
Relentless and unexplained destruction of UMN and anterior horn cells in CNS
What distinguishes MND from MS and polyneuropathies
NO SENSORY LOSS OR SPHINCTER DISTURBANCES seen
NO EYE MOVEMENTS AFFECTED (MG differentiated)
What causes MND
Oxygen species which damage lipids, DNA and proteins
How do patients with NMD die
3 years from res failure due to bulbar palsy and pneumonias
What is ALS
Death of neurones of voluntary muscles
Clinical presentation of ALS
UMN and LMN
- Weakness and UMN signs (upping planters + LMN wasting in ONE LIMB)
- Split hand sign - thumb side of the hand is adrift due to excessive wasting around int but less than hypothenar
- Cramps
- Brisk reflexes in wasted muscles, extensor plantar response and spasticity
- Foot drop and wrist drop
Clinical presentation of progressive muscular atrophy
LMN ONLY:
- Weakness
- Muscle wasting
- Fasciculations in one limb that spread to other spinal segment s
- Affects distal muscle groups before proximal
Clinical presentation of progressive bulbar palsy
LMN ONLY:
- CN 9,10,11,12 affected initially
- Dysarthria, dysphagia, nasal regurgitation of fluids and choking
- LMN lesions affecting tongue and talking/swallowing muscles
- Flaccid, fasciculation tongue
- Jaw jerk absent
- Speech quiet, horse or nasal
Clinical presentation of primary lateral sclerosis
UMN ONLY:
- Loss of Betz cells in motor cortex
- Main UMN signs in legs
- Causes pseudo bulbar palsy
Complications of MND
- FORNTOTEMPORAL DEMENTIA
What patients will have MND
Over 40 Stumbling spastic gait Foot drop Proximal myopathy Weak grip (door handles don't turn) Hair-washing is hard (poor shoulder abduction) Aspiration pneumonia
Differential diagnosis of MND
- MS
- MG
- Diabetic amyotrophy
- Guillain-Barre syndrome
- Spinal cord tumours
How is MND diagnosed
- LMN + UMN in 3 regions - definite
- LMN + UMN in 2 regions - probable
- LMN + UMN in 1 region + EMG shows acute denervation in more than 2 limbs
- LMN + UMN signs in 1 legion
- MRI of CNS: exclude structural causes
- Lumbar puncture (exclude inflammatory causes
- NCS + EMG: Denervation of muscles due to degeneration of LMN confirmed by EMG
Treatment of MND
- Antiglutamatergic drugs
- ORAL AMITRYPTYLINE for muscles of mastication
- Dysphagia (Nasogastric tube)
- Spasms: ORAL BACLOFEN
- Ventilation for res failure
- DICLOFENAC
- Speech, language therapists and physic
Define Guillain-Barre syndrome
Acute inflammatory demyelinating ascending polyneuropathy affecting PNS Schwann cells following upper res infection or GI infection
What gender is affected din GBS
MALES
Peka age for GBS
15-35 and 50-75
What microbes cause GNS
- Campylobacter jejune
- Cytomegalovirus
- Mycoplasma
- Zoster
- HIV
- EBV
What does Campylobacter jejune do
Causes diarrhoea
Pathophysiology of Guillain-Barre syndrome
—— Shwann cell attack—-
Immune attack on nerve cells of PNS
2. T cells and macrophages damage myeline sheets
3, Activation of complements
—–Axon attack—-
IgG antibodies and complement against cell membrane covering axon without lymphocyte involvement
How do microbes cause GNS
Share same antigens are Schwann cells leading to autoantibody mediated nerve cell damage formation
Diagnosis of Guillain-Barre syndrome
- Lumbar puncture: Elevated protein (greater than 0.55g/L levels and fewer than 10 WBC/mm^3
- NCS and EMG may show delayed nerve conduction of electrical impulses (not seen until after 2 weeks)
- Spirometry to monitor FVC if there is res involvement
Differential diagnosis of GBS
- Hypokalaemia
- Stroke
- Brianstem compression
- Encephalitis
- Spinal cord compression
- Poliomyelitis
- Vasculitis
- MG
Clinical presentation of GBS
- 1-3 weeks post infection sees BILATERAL ASCENDING MUSCLE WEAKNESS = paralysis
- PROXIMAL MUSCLES more affected (trunk, res and cranial nerve 7)
- Pain
- Paraesthesias
- Reflexes lost
- Systemic symptoms: Sweating, Raised BP , arrhythmias
How is GBS treated
- VENTILATE if FVC < 1.5L/80%
- IV IG for 5 days to reduce paralysis
- Plasma exchange
- LOW MOLECULAR WEIGHT HEPARIN + compression stockings to reduce risk of venous thrombosis
When is IV IMMUNOGLOBULIN contraindicated
IgA deficiency patients
6 ways we can get nerve malfunctions
- DEMYELINATION
- AXONAL DEGENERATION
- COMPRESSION
- INFARCTION
- INFILTRATION
- WALERIEN DEGENERATION
What happens to conduction velocity in axonal degeneration
Normal because axonal continuity is maintained in surviving fibres
Name a condition that causes compression of nerve
CARPAL TUNNEL SYNDROME
How does infarction lead to nerve malfunction
- Micro-infarction of vast nervous occurs in diabetes and arthritis such as polyarteritis nods and eosinophilic granulomatosis and polyangitis
How doe infiltration cause nerve damage
- Inflammatory cells in leprosy and granulomas
What is wallerian degeneration
When nerve fibre is cut or crash, distal part of axon separated from cell body degenerates
Define neuropathy
Pathological process affecting peripheral nerve or nerves
Define mononeuropathy
Process affecting single nerve
Define mononeuritis multiplex
Several individual nerves affected
What causes mononeuropathies
Lesions of individual peripheral or cranial nerves (trauma, entrapment)
What is mono neuritis multiplex
When 2 or more peripheral nerves are affected when causes are systemic
What conditions can cause mono neuritis multiplex
- WARDS PLC
W - Wegener’s grnaulomatosis
- AIDS/AMYLOID
- RA
- Diabetes mellitus
- Sarcoidosis
- POlyarteritis nodosa
- Leprosy
- Carcinoma
Most common mononeuropathy
Carpal tunnel syndrome
What conditions are associated with carpal tunnel d=syndrome
- Hypothyroidism
- Diabetes mellitus
- Pregnancy
- Amyloidosis
- Obesity
- RA
- Acromegaly
Clinical presentation of carpal tunnel syndrome
- Ahcing pain in hand and arm AT NIGHT makes patient wake up
- Paraesthesiae in thumb, index, middle and 1/2 ring fingers and palm (median nerve distribution)
- Relieved by dangling hand over edge of bed
- Sensory loss and weakness of ABUDCTOR POLICES BREVIS and wasting of thenar eminence (muscles at base of thumb)
- Light touch, 2-point discrimination and wearing impaired
Differential diagnosis of CTS
- Peiprheral neurooathy
- MND
- MS
Diagnosis of Carpal tunnel syndrome
- EMG (shows slowing of conduction velocity in median nerve, confirms lesion site and severity)
- PHALEN’s test (patient can only maximally flex wrist for 1 minute)
- TINEL’s test (tapping never on wrist causes tingling)
How is Capral tunnel treated
- Wrist splint at night
- Steroid injetcion
- Decompresison surgery (carpal tunnel ligament cut to reduce pressure)
What are MuSK proteins
Receptor tyrosine kinase
What are MuSK proteins needed for
Formation and maintenance of the NMJ