Neurology: MS and Neuromuscular Weakness Flashcards
1
Q
What is the typical patient groups for patients with multiple sclerosis?
A
- MS is the most common disease of the central nervous system affecting young adults commonly between 25 to 35
- Typical patient is a white women in her 20s. Onset before puberty or after 50 years of age is rare
- Female to male ratio is 2:1
2
Q
What is Multiple sclerosis?
A
Multiple sclerosis is an inflammatory demyelinating conditions which eventually leads to axonal loss. This can lead to neurodegeneration.
- May present with non-specific features (e.g. 75% of patients have significant lethargy)
- Diagnosis can be made on the basis of two or more relapses and either objective clinical evidence of two or more lesions or objective clinical evidence of one lesion together with reasonable historical evidence of a previous relapse.
3
Q
What are symptoms and signs of Multiple Sclerosis?
A
-
Visual
- Optic neuritis: common presenting feature
- Optic atrophy
- Uhthoff’s phenomenon: worsening of vision following rise in body temperature
- Internuclear ophthalmoplegia
-
Sensory
- Pins/needles
- Numbness
- Trigeminal neuralgia
- Lhermitte’s syndrome: paraesthesia in limbs on neck flexion
-
Motor
- Spastic weakness: most commonly seen in the legs
-
Cerebellar
- Ataxia: more often seen during an acute relapse than as a presenting symptom
- Tremor
-
Others
- Urinary incontinence
- Sexual dysfunction
- Intellectual deterioration
4
Q
What are the areas affected by Multiple Sclerosis?
A
- Brain hemisphere (supra-tentorium)
- Brainstem
- Cerebellum (infra-tentorium)
- Spinal Cord
- Optic Nerves
5
Q
What are causes of MS?
A
- Genetics
- MS susceptibility appears to correlate most strong with mutations in the human leukocyte antigen Major Histocompatibility Complex (MHC) human leukocyte antigen (HLA) gene regions
- Environmental factors
- Sunlight - vitamin D deficiency may increase susceptibility
- Diet
- Smoking
- Infections
- Saturated fat
- Autoimmune disease: Inflammation secondary to autoimmune processes drives MS and give rises to neuronal loss and neurodegeneration which eventually causes disability
6
Q
How do infections lead to multiple sclerosis?
A
-
Molecular Mimicry
- Genetically susceptible patient exposed to a viral agent, the immune response to the virus cross-reacts to an epitope of a myelin autoantigen, a concept known as molecular mimicry.
- Activated myelin-reactive lymphocytes then migrate into the CNS where they recognize myelin autoantigen and elicit inflammation.
- Human herpes virus type 6
- more recent data implicate Epstein-Barr virus infection (mononucleosis)
-
Bystander theory
- Viruses may also incite immune responses in ways other than molecular mimicry, such as by causing bystander damage. Such damage exposes previously secluded epitopes to immune responses, resulting in a self-perpetuating autoimmune response.
7
Q
What is the management for multiple sclerosis?
A
MS
8
Q
What is the pathophysiology of Gullian-Barre Syndrome?
A
Post-infectious but aetiology unknown.
- Frequently preceded by infection, trauma, surgery, vaccination, pregnancy or other immune system stimulation
- Cross-reaction with schwann cell/ (axolemma) antigens. T-cell sensitization leads to damge to Myelin and Axons.
- Impaired neurotransmission to the periphery
- It is rapidly progressive and potentially fatal
- Commonest western acute flaccid paralysis with a bimodal peak (commonest in elderly).
- Affects the pripheral nervous system leading to peripheral neuropathy
9
Q
What are clinical manifestations of Gullian Barre syndrome?
A
- Usually develops 1 to 3 weeks after UTI or GI infection (Campylobacter common)
- Complaints of backache often
- Pain in the form of muscles cramps or hyperesthesias (worse at night)
- Respiratory Muscle Weakness
- Cranial nerve involvement e.g. diplopia
- Autonomic Involvement e.g. urinary retention, diarrhoea
- Brief plateau – recover over weeks to months
- Sensory symptoms tend to be mild (e.g. distal paraesthesia) with very few sensory signs
- Papilledema: thought to be secondary to reduced CSF resorption although less common
- Around 65% of patients experience back/leg pain in the initial stages of the illness
- Symptoms peak by 4 weeks – can be recurrent
10
Q
What are diagnositic criteria for Gullian Barre syndrome?
A
-
Required features:
- Progressive weakness in both arms and legs which classically ascends
- Areflexia (or hyporeflexia)
-
Features supportive of diagnosis:
- Progression of symptoms over days to 4 weeks
- Relatively symmetric
- Mild sensory signs or symptoms
- CN involvement, especially bilateral facial weakness
- Recovery begins 2-4 weeks after progression ceases
- Autonomic dysfunction
- Absence of fever at onset
- Typical CSF and EMG/NCS features
11
Q
What are diagnostic studies for Gullian Barre Syndrome?
A
- Based on history and physical examination
-
EMG/NCS
- Nerve conduction studies may be performed
-
Lumbar Puncture
- CSF: Rise in protein with a normal white blood cell count (albuminocytologic dissociation) - found in 66%
- Increased in protein takes 1-2 weeks to develop
- CSF: Rise in protein with a normal white blood cell count (albuminocytologic dissociation) - found in 66%
-
Campylobacter serology if GI upset
- AMAN – anti GM1, C jejuni
- MF – anti GQ1B
-
Anti-ganglioside antibodies
- Stool cultures
- Throat Swab
12
Q
What ae complications of Gullian Barre Syndrome?
A
- Autonomic nervous system dysfunction results from alterations in sympathetic and parasympathetic nervous systems.
- Cardiac arrhythmias (sinus tachy-, brady-, tachyarrhythmias), Postural hypotension, Hypertension, Urinary retention, Ileus
- Respiratory failure (25%) - most serious
- Pain
- DVT/ PE
- SIADH
- Renal failure – secondary to IV Ig
- Hypercalcaemia (immobility)
13
Q
How is respiratory failure resulting from GBS managed?
A
Bedside spirometry
- FVC
- If falling rapidly or FVC< 20ml/kg revue as as may need respiratory support
- Blood gases ↑CO2 ↓O2 acidosis – late manifestations of type II respiratory failure
14
Q
How is Gullian Barre syndrome therapeutically managed?
A
- General
- Close observation as weakness is progressive
- Bedside spirometry
- Ventilatory support
- ECG +/- cardiac monitoring
- Nutritional support +/- NG tube
- DVT prophylaxis
- May need urinary catheter
- Laxatives and bowel care
- Pain control – usually opiates
- Specific
- IV immunoglobin
- Plasmapheresis used within the first 2 weeks of onset. After three weeks, plasmapharesis no benefit
- NB steroids not effective
15
Q
What is the pathology of Myasthenia Gravis?
A
- Autoimmune disease with antibodies (IgG) blocking the binding site for AcH at the neuromuscular junction. Ach rarely binds as a result and Ach-esterase begins to break it down
