Investigations
The nature of the investigations undertaken depends on whether the patient is one in whom MS is a new diagnostic possibility or a patient where the diagnosis is already known.
In a patient suspected with MS in the ED, before specialist referral
The priority is to rule out other differentials by the following recommended initial tests10:
| 1. Full blood count | Significant anaemia |
| 2. Inflammatory markers (ESR, CRP) | Alternative infectious or inflammatory process |
| 3. Liver function tests | Baseline function before treatment |
| 4. Renal function tests | Renal function needed for further contrast neuroimaging |
| 5. Calcium | Hypocalcaemia – MS like sensory symptoms
Hypercalcemia in sarcoidosis |
| 6. Glucose | Diabetic peripheral neuropathy, hypoglycaemia |
| 7. Thyroid function tests | Hypothyroidism – MS like sensory symptoms |
| 8. Vitamin B12 | Deficiency related neurologic deficit |
| 9. HIV serology | HIV can mimic MS due to transverse myelitis
HIV may be associated with neurosyphilis |
Further investigations for patients in whom a diagnosis of MS is possible
CT scanning of the brain may be indicated if the differential diagnosis suggests an acute intracerebral pathology.
MRI for the exclusion of a surgically decompressible spinal cord lesion in patients with symptoms consistent with acute transverse myelitis.
CSF analysis may be indicated if the diagnosis is uncertain and the presentation raises suspicion of CNS infection. CSF protein and gamma globulin concentrations are elevated in many MS patients although some patients with MS will have normal or atypical CSF findings.
Serum electrolytes to determine abnormalities associated with neurological or muscular defects – potassium, calcium, phosphate; coagulation screen if lumbar puncture is considered.
Further evaluation may be carried by the specialist/ neurologist based on individual presentation and may include syphilis serology, autoimmune screening etc
Learning bite
There is no single diagnostic test for MS in patients who present with signs consistent with MS, and in whom the diagnosis has not been made previously, urgent discussion with a Neurologist and MRI scanning is required.
Investigations for patients in whom a diagnosis of MS is established already
In patients with known MS who present with a further decline in their neurological function, investigations are required to identify reversible causes. Routine investigations will include:
- Full blood count with differential to look for infection
- Urinalysis to exclude urinary tract infection (UTI) (see Management page)
Learning bite
Investigations in the ED will largely be focussed on management of acute complications of MS such as fever and urinary tract infection and the exclusion of serious reversible alternative diagnoses, especially spinal cord compression