Editing Peripheral neuropathy (section)

==Diagnosis==
Peripheral neuropathy may first be considered when an individual reports symptoms of numbness, tingling, and pain in feet. After ruling out a lesion in the central nervous system as a cause, a diagnosis may be made on the basis of symptoms, laboratory and additional testing, clinical history, and a detailed examination.

During [[physical examination]], specifically a [[neurological examination]], those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, although those with a [[pathology]] (problem) of the nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies, such as [[Guillain–Barré syndrome]]; or may show focal sensory disturbance or weakness, such as in mononeuropathies. Classically, [[ankle jerk reflex]] is absent in peripheral neuropathy.

A physical examination will involve testing the [[Neurological examination#List of tests|deep ankle reflex]] as well as examining the feet for any [[ulceration]]. For large fiber neuropathy, an exam will usually show an abnormally decreased sensation to vibration, which is tested with a 128-Hz [[tuning fork]], and diminished sensation of light touch when touched by a nylon monofilament.<ref name="WatsonDyck2015"/>

Diagnostic tests include [[electromyography]] (EMG) and [[nerve conduction studies]] (NCSs), which assess large myelinated nerve fibers.<ref name="WatsonDyck2015"/> Testing for small-fiber peripheral neuropathies often relates to the [[autonomic nervous system]] function of small thinly- and unmyelinated fibers. These tests include a sweat test and a tilt table test. Diagnosis of small fiber involvement in peripheral neuropathy may also involve a skin biopsy in which a 3&nbsp;mm-thick section of skin is removed from the calf by a [[Skin biopsy#Punch biopsy|punch biopsy]], and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the skin.<ref name="CioroiuBrannagan2014"/> Reduced density of the small nerves in the epidermis supports a diagnosis of small-fiber peripheral neuropathy.

In EMG testing, demyelinating neuropathy characteristically shows a reduction in conduction velocity and prolongation of distal and F-wave latencies, whereas axonal neuropathy shows a reduction in amplitude.<ref>{{cite journal |last1=Chung |first1=Tae |last2=Prasad |first2=Kalpana |last3=Lloyd |first3=Thomas E. |title=Peripheral Neuropathy – Clinical and Electrophysiological Considerations |journal=Neuroimaging Clinics of North America |date=February 2014 |volume=24 |issue=1 |pages=49–65 |doi=10.1016/j.nic.2013.03.023 |pmid=24210312 |pmc=4329247 }}</ref>

Laboratory tests include blood tests for [[vitamin B12|vitamin B<sub>12</sub>]] levels, a [[complete blood count]], measurement of [[thyroid stimulating hormone]] levels, a [[comprehensive metabolic panel]] screening for diabetes and pre-diabetes, and a [[serum immunofixation test]], which tests for antibodies in the blood.<ref name="Azhary2010">{{cite journal | vauthors = Azhary H, Farooq MU, Bhanushali M, Majid A, Kassab MY | title = Peripheral neuropathy: differential diagnosis and management | journal = American Family Physician | volume = 81 | issue = 7 | pages = 887–92 | date = April 2010 | pmid = 20353146 }}</ref>