Laboratory Tests and Ancillaries
Ancillary tests may be conducted to document the presence of a specific underlying neurologic disease or confirm a sensory lesion within the pain distribution.
Laboratory Tests
Laboratory tests are quantitative means to measure objective response. These can help confirm the clinical diagnosis or exclude other diseases that can mimic the health condition causing neuropathic pain and can also help find treatable causes of neuropathic pain syndromes.
Skin Biopsy
Neuropathic Pain_Diagnostics
Skin biopsy is the best tool for assessing neuropathies with distal loss of unmyelinated nerve fibers. This is recommended in patients with painful or burning feet of unknown origin and with a clinical impression of small fiber dysfunction.
Additional Tests to Identify Other Causes of Neuropathies
Additional tests to identify other causes of neuropathies are fasting blood sugar, HbA1c, glucose tolerance test, lipid profiles, kidney, liver, and thyroid function tests, vitamin B12 levels, HIV 1/2 viral load and CD4+ T-lymphocyte counts, and lumbar puncture.
Imaging
Imaging studies are encouraged in patients with neuropathic pain.
Cranial Computed Tomography (CT) Scan
A cranial CT scan facilitates specific diagnosis and helps confirm stroke or other brain space-occupying lesions.
Magnetic Resonance Imaging (MRI)
A magnetic resonance imaging can identify small patches of inflammation in peripheral nerves. This is recommended as part of the initial work-up of patients with trigeminal neuralgia and is the first-line modality for diagnosing secondary TN. MRI plain and with contrast may be done to rule out pathology (eg inflammation, infection, inflammation, demyelination, etc), involving the CNS (brain or spinal cord).
Plain Film Radiography
Plain film radiography is used to rule out spondylosis, disc disease, spondylolisthesis, neuroforaminal stenoses, or compression deformity.
Three-Phase Bone Scan
A three-phase bone scan may help in the diagnosis of complex regional pain syndrome.
Positron Emission Tomography (PET)
A positron emission tomography measures cerebral blood flow or metabolic activity in defined brain regions.
Activation Studies
Activation studies investigate local synaptic changes specifically associated with a given task or a particular stimulus by comparing statistically activated and controlled conditions.