Neurology
Question 92 of 180
You have been asked to give a teaching session to a group of medical students attached to the Emergency Department. The title of the session is "Neurological Conditions in the ED". You are discussing multiple sclerosis (MS). Which of the following best describes the MRI findings in MS?
Answer:
Longitudinally extensive transverse myelitis is unusual in multiple sclerosis (MS). Whilst grey matter is affected in MS, and there is some evidence that overall grey matter volume decreases in MS and correlates with disability, focal grey matter inflammatory lesions would not be expected, and the focal lesions are in fact found in the white matter. The cerebellum and brainstem are affected in multiple sclerosis, however, not exclusively. White matter lesions are classically described as “periventricular”, and the lesions found do not always correlate with a clinical focus of disease. This is because the central nervous system (CNS) inflammation does not always cause demyelination or axonal damage of clinical significance, and the CNS can recover from these foci of inflammation.Multiple Sclerosis
Neurology
Last Updated: 12th February 2021
Multiple sclerosis (MS) is an acquired, chronic, immune-mediated, inflammatory condition of the central nervous system (CNS) that can affect the brain, brainstem, and spinal cord. The inflammatory process causes areas of demyelination (damage to white matter), gliosis (scarring), and neuronal damage throughout the CNS.
Patterns of disease
Onset of MS is typically in young adulthood — neurological symptoms and signs vary widely and include visual and sensory disturbances, limb weakness, gait problems, and bladder and bowel symptoms. Although it is impossible to predict when a relapse will occur, known possible triggers include infection, stress, and the postpartum period.
There are three main patterns of the disease:
- Relapsing-remitting MS (RRMS).
- RRMS is the most common pattern of disease — about 85% of people with MS have RRMS at onset. Episodes or exacerbations of symptoms (relapses) are followed by recovery (remissions) and periods of stability.
- Secondary progressive MS (SPMS).
- SPMS occurs when there is a gradual accumulation of disability unrelated to relapses, which become less frequent or stop completely. About two thirds of people with RRMS progress to SPMS.
- Primary progressive MS (PPMS).
- In PPMS there is a steady progression and worsening of the disease from the onset, without remissions. PPMS occurs in about 10–15% of people with MS.
Risk factors
The cause of multiple sclerosis (MS) is unknown — it is thought that acute then chronic immune-mediated inflammation is precipitated by an abnormal response to environmental triggers in people who are genetically predisposed. A combination of risk factors may contribute to triggering an autoimmune response and development of multiple sclerosis (MS), these include:
- Genetics
- Vitamin D deficiency
- Cigarette smoking
- Diet and obesity in early life
- Latitude — in general, the prevalence of MS increases the greater the distance north or south from the equator.
- The Epstein–Barr virus (EBV)
- Female gender – MS is 2–3 times more common in women than in men.
Clinical features
Multiple sclerosis (MS) typically presents between 20–50 years of age.
MS can affect nearly any part of the central nervous system. Presenting symptoms and signs can vary greatly and may include:
- Loss or reduction of vision in one eye with painful eye movements.
- Diplopia.
- Ascending sensory disturbance and/or weakness.
- Balance problems, unsteadiness, or clumsiness.
- Altered sensation radiating down the back and sometimes into the limbs on neck flexion (Lhermitte's symptom).
The most common initial presentations are:
- Optic neuritis — inflammation of the optic nerve.
- Optic neuritis is the initial presentation in about 20–30% of people with MS.
- The person may describe partial or total unilateral visual loss developing over a few days, pain behind the eye (in particular on eye movement) and/or loss of colour discrimination (particularly reds).
- Fundoscopy is often normal but the disc may appear pale or swollen. There may be paradoxical dilation of the pupil when light is rapidly shifted from the unaffected eye to the affected eye (relative afferent pupillary defect).
- Optic neuritis may be bilateral, but if this occurs extra vigilance is needed to rule out neuromyelitis optica which is often confused with MS and needs urgent treatment.
- Transverse myelitis — focal inflammation within the spinal cord.
- May present with sensory symptoms (such as paraesthesia) or motor symptoms (such as weakness) below the level of the inflammation that typically develop over hours or days.
- Some people describe a tight band sensation around the trunk at the level of the inflammation, or a shock-like sensation radiating down the spine induced by neck flexion (Lhermitte’s phenomena).
- There may be urinary symptoms such as urgency, frequency, or retention.
- Examination may reveal focal muscle weakness and reduced sensation below the affected spinal level.
- Symptoms and signs may be symmetrical or asymmetrical, and tend to reflect a partial myelitis that only affects a part of the spinal cord — symptoms and signs similar to a full spinal cord transection are rare.
- Cerebellar-related symptoms.
- These may include ataxia, vertigo, clumsiness, and dysmetria (as demonstrated by abnormalities with finger-to-nose testing and walking heel to toe).
- Brainstem syndromes — these may result in:
- Ataxia.
- Eye movement abnormalities that can cause diplopia, oscillopsia (a sensation of movement of the vision), nystagmus, and internuclear ophthalmoplegia (inability to adduct one eye and nystagmus in the abducting eye on oculomotor examination).
- Bulbar muscle problems resulting in dysarthria or dysphagia.
Differential diagnosis
- Other demyelinating diseases:
- Neuromyelitis optica
- Idiopathic transverse myelitis
- Acute disseminated encephalomyelitis
- Metabolic disorders:
- Vitamin B12 deficiency
- Diabetic peripheral neuropathy
- Hypocalcaemia
- Hypothyroidism
- Copper deficiency
- Adult-onset leukodystrophies
- Infections:
- Lyme disease
- Tertiary syphilis
- HIV
- Tropical spastic paraparesis
- Vascular disorders:
- Primary CNS vasculitis
- Ischaemic stroke
- Systemic inflammatory disorders:
- Systemic lupus erythematosus
- Behcet's syndrome
- Sarcoidosis
- Neoplasia:
- Primary or metastatic neoplastic brain lesions
- Paraneoplastic syndromes
Diagnosis and management
- If a person has symptoms and signs suggestive of multiple sclerosis (MS) refer promptly to a consultant neurologist — early diagnosis and treatment may improve prognosis. Only a consultant neurologist should make a diagnosis of MS.
- Arrange blood tests to help exclude alternative diagnoses, including:
- Full blood count.
- Inflammatory markers, for example, erythrocyte sedimentation rate or C-reactive protein.
- Liver function tests.
- Renal function tests.
- Calcium.
- Glucose/HbA1c.
- Thyroid function tests.
- Vitamin B12.
- HIV serology.
- Specialist investigations:
- MRI brain/spinal cord
- 95% of patients have periventricular lesions and over 90% show discrete white matter abnormalities. Areas of focal demyelination can also be seen as plaques in the optic nerve, brainstem and spinal cord. By using a contrast agent, active inflammatory plaques can be distinguished from inactive ones. The number and size of lesions do not correlate well with disease activity or progress. It also excludes other lesions producing the symptoms.
- Lumbar puncture
- CSF analysis may show rise in total protein with increase in immunoglobulin concentration with presence of oligoclonal bands.
- Evoked potential test
- Can detect demyelination in apparently unaffected pathways with characteristic delays. Visual evoked potential studies should be the first choice.
- MRI brain/spinal cord
- A consultant neurologist will normally confirm the diagnosis of multiple sclerosis (MS) based on established up-to-date criteria such as the revised McDonald criteria after:
- Confirming that episodes are consistent with an inflammatory process.
- Excluding alternative diagnoses.
- Establishing that lesions have developed at different times and are in different anatomical locations for a diagnosis of relapsing-remitting MS.
- Establishing progressive neurological deterioration over at least 1 year for a diagnosis of primary progressive MS.
- If the diagnosis is confirmed, the specialist team will:
- Consider whether treatment with disease-modifying therapy (DMT) is appropriate.
- Organise multidisciplinary management and follow up of the person, as appropriate to their needs and severity of the disease.
- Advise if prescription of short course high-dose steroids is recommended for relapse. The standard treatment is oral methylprednisolone 0.5 g daily for 5 days. This should be offered as early as possible and within 14 days of onset of symptoms.
Complications
As lesions can develop almost anywhere in the brain or spinal cord of a person with multiple sclerosis (MS), a large range of complications may develop including:
- Fatigue
- Spasticity
- Ataxia and tremor
- Visual problems
- Reduced mobility
- Pain
- Bladder problems
- Sexual dysfunction
- Mental health problems
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
