Neuromuscular Disorders Flashcards
What are the sx of NMD?
-Muscle weakness/wasting;
-sensory loss/numbness;
-clumsiness;
-poor balance;
-diplopia;
-dysphagia;
-dyspnoea etc.
Also cramps, burning, stiffness
What is Charcot Marie Tooth disease?
Inherited distal predominant group of disorders.
Genetically determined, chronic, slowly progressive and gradually disabling disorders.
Important Hx features of NMD?
Time: acute or chronic
FHx: any similar presentations in family
Which NMD conditions cause diplopia and ptosis?
Myasthenia Gravis
Ocular nerve palsy
Thyroid eye disease
NOT MND
What are the head and neck sx of NMD?
Diplopia, ptosis
Dysphagia
What are the clinical features of MND?
- Muscle wasting (including tongue)
- Fasiculations
- Tone (increased or decreased)
- Generalised weakness (no pattern)
- Reflexes preserved until late (or exaggerated)
- Plantars may be upgoing
- NO SENSORY LOSS
- Cranial nerves (except bulbar) spared
What is the commonest MND?
Amyotrophic lateral sclerosis
Peak onset ALS?
55 - 70 years
How is ALS diagnosed?
- Clinical; UMN and LMN signs with intact sensation.
- Consistent lab findings - EMG
- Exclusion of other diagnoses
What is the prognosis of MND?
Avg life expectancy
Bulbar onset: 6-12 months
Limb onset: 2 - 5 years
What is the Mx MND?
Supportive: -speech path swallow and communication, peg feeding. -non-invasive ventilation -mobility adis Rx: riluzole 50mg bd
What is hereditery spastic paraplegia?
Spasticity of lower limbs; realtively preserved strength.
Inherited, mutations in spatin gene.
What is adenomyeloneuropathy?
X-linked disorder of excess long chain fatty acids
What is primary lateral sclerosis?
Similar to ALS but no LMN signs.
Better prognosis
What is lamberton eaton myasthenia syndrome?
Presynaptic ABs vs Ca2+ channels
Often associated with neoplasms of small cell lung
What is the Tensilon test?
Short acting acetylcholinesterase antagonist (e.g. edrophonium)
Dx of MG
What bloods for MG Dx?
Autoantibodies for ACh receptor
- pure ocular positive (50%)
- Gnereliased MG positive (90%)
- Seronegative cases approx 70% +ve for anti MuSK Abs
What tests for MG diagnosis?
Tensilon test
Bloods - autoantibodies
CT chest
EMG
How is myasthenia graves treated?
- Immune modulation (plasma exchange, IV Ig, immunosuppression)
- Acetylcholinesterase antagonists
- Thymectomy
What are the common types of focal neuropathy?
Compressive: Ulnar neuropathy Infection: leprosy Inflammatory e.g. Bell's Palsy Infiltrative: cancer, amyloid Ischaemic: e.g. DM
How are compressive neuropathies diagnosed?
History of focal symptoms
EMG/NCS
What are the causes of multifocal neuropathies? (mono neuritis multiplex)
Almost always ischaemic e.g. diabetes, vasculitis
Occasionally infective: AIDS, CMV, sarcoidosis, leprosy
Why is mono neuritis multiplex a medical emergency?
Often due to vasculitis (if not DM). Nerves will progressively infarct - cannot be restored.
What are the acute demyelinating polyneuropathies?
- Guillain-Barre Syndrome
- AIDS seroconversion phase
- Lymphoma
What are the causes of acute axonal neuropathy?
- Glue sniffers neuropathy (N-Hexane toxicity)
- Vasculitis
- Thiamine deficiency
- Porphyria
What do sensory disturbances exclude?
MND, MG and myopathy
What does electrophysiology distinguish between?
Distinguishes:
- neuropathy from myopathy
- axonal from demyelinating
- sensory v motor
- NMJ disorder
What are the causes of chronic axonal polyneuropathy?
- Genetic: HMSN II
- Metabolic: DM, hypothyroidism
- Toxins: EtOH, drugs, prescription Rx, Heavy metals
- Nutritional: thiamine, B12 deficiency, B6 excess
- Paraneoplastic: Anti Hu
- Immune: abnormal paraprotein, Sjogren’s
- Ischaemic: diabetes, vasculitis
What are the causes of chronic demyelinating polyneuropathies?
- Genetic: HMSN Type 1
- Immune: inflammatory (CIDP), non-inflammatory (IgM anti-MAG)
- Paraneoplastic: POEMS
