Differentials
Myelopathy due to cervical spondylosis
SIGNS / SYMPTOMS
The patient's symptoms and signs are all below the neck (although they may have dizziness and headache).
INVESTIGATIONS
MRI of the cervical spine shows compression of the spinal cord.
Fibromyalgia
SIGNS / SYMPTOMS
Generalised weakness and non-specific fatigue are common.
Neurological examination is normal apart from possible functional overlay.
INVESTIGATIONS
MRI brain may show non-specific white matter changes, but not the characteristic MS findings.
Postural orthostatic tachycardia syndrome with or without cervicogenic migraine
SIGNS / SYMPTOMS
History is significant for headaches and dizziness, particularly with change of head position or standing. Examination is normal.
INVESTIGATIONS
MRI of the cervical spine may show cervical spondylosis.
Tilt table testing may be abnormal.
Sleep disorders
SIGNS / SYMPTOMS
Patient describes non-restful sleep with variable features of snoring, restless legs, and apnoea. Memory changes and mood disturbances may be prominent. Neurological examination is normal.
INVESTIGATIONS
Abnormal sleep study.
Sjogren syndrome
SIGNS / SYMPTOMS
Symptoms of dry eyes and dry mouth as well as joint stiffness and pain. Neurological examination is usually normal.
INVESTIGATIONS
Elevated autoantibodies (anti-Ro/SSA and anti-La/SSB).
MRI brain and spinal cord are normal.
Vitamin B12 deficiency
SIGNS / SYMPTOMS
Numbness, fatigue, and possible memory loss. Posterior column loss of sensation (vibration and proprioception) in the presence of increased reflexes on examination.
INVESTIGATIONS
Low vitamin B12 level, high methylmalonic acid level.
MRI does not show characteristic lesions of MS.
Ischaemic stroke
SIGNS / SYMPTOMS
History indicates sudden onset of symptoms. Signs and symptoms usually explainable on the basis of a single neurological lesion, rather than multiple lesions.
INVESTIGATIONS
CT head shows ischaemic changes.
Diffusion-weighted MRI will be abnormal in the acute setting.
Peripheral neuropathy
SIGNS / SYMPTOMS
Loss of sensation and reflexes in the feet and hands if large nerve fibre, severe pain if small nerve fibre.
INVESTIGATIONS
Abnormal electromyogram if large nerve fibre, abnormal skin biopsy for number of nerve fibres if small fibre.
Blood tests for specific cause (e.g., haemoglobin A1c [HbA1c] or thyroid-stimulating hormone) are abnormal.
Lymphoma
SIGNS / SYMPTOMS
Patient has gradual onset of severe disability.
INVESTIGATIONS
MRI shows persistent enhancing lesion over time, which may worsen despite treatment.
Neoplastic cells seen on cerebrospinal fluid cytology.
Inherited disorders such as mitochondrial diseases and leukodystrophies
SIGNS / SYMPTOMS
Patient has gradual onset of memory or cognitive problems, sometimes in the setting of neuropathy.
INVESTIGATIONS
MRI appearance is quite distinct and includes prominent symmetrical white matter changes and normal spinal cord MRI.
Some blood tests are available for specific disorders.
Sarcoidosis
SIGNS / SYMPTOMS
Patient may have prior history of pulmonary sarcoid and shortness of breath.
INVESTIGATIONS
Highly elevated serum ACE level.
Abnormal chest x-ray and gallium scans.
MRI brain non-specific white matter changes; MRI brain or spinal cord may show meningeal enhancement.
Guillain-Barre syndrome
SIGNS / SYMPTOMS
Loss of reflexes with predominantly motor symptoms. Dangerous respiratory complications are more common.
INVESTIGATIONS
MRI is normal.
Cerebrospinal fluid shows characteristic cytoalbumin dissociation, and the classical MS findings of oligoclonal bands and elevated IgG and IgG synthesis are absent.
Amyotrophic lateral sclerosis (ALS)
SIGNS / SYMPTOMS
Mixed upper and lower motor neuron signs are present: increased reflexes (upper motor neuron) with atrophy and fasciculations (lower motor neuron).
Visual changes are absent.
ALS may involve dysphagia and pulmonary function abnormalities, but the dysphagia, unlike in MS, is usually accompanied by tongue fasciculations and dysphonia.
INVESTIGATIONS
Electromyogram is diagnostic of ALS. It is normal in MS unless there is a comorbidity such as diabetes or B12 deficiency.
Compressive lesions may resemble ALS and MRI of the spinal cord is recommended to exclude compressive syndromes; if MS is present, characteristic lesions are usually seen on MRI.
Muscle biopsies are useful to exclude primary muscle pathology.
Systemic lupus erythematosus
SIGNS / SYMPTOMS
Patient may have fevers, joint pain and swelling, muscle tenderness, (malar) rash.
INVESTIGATIONS
Elevated anti-nuclear antibodies (however, it is common to have mild elevation in MS), positive anti-DS DNA.
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