In people with diabetes mellitus, mononeuritis multiplex typically is encountered as acute, unilateral, and severe thigh pain followed by anterior muscle weakness and loss of knee reflex.Electrodiagnostic medicine studies will show multifocal sensory motor axonal neuropathy.It is caused by, or associated with, several medical conditions:

Autonomic neuropathy
Autonomic neuropathy is a form of polyneuropathy that affects the non-voluntary, non-sensory nervous system (i.e., the autonomic nervous system), affecting mostly the internal organs such as the bladder muscles, the cardiovascular system, the digestive tract, and the genital organs. These nerves are not under a persons conscious control and function automatically. Autonomic nerve fibers form large collections in the thorax, abdomen, and pelvis outside the spinal cord. They have connections with the spinal cord and ultimately the brain, however. Most commonly autonomic neuropathy is seen in persons with long-standing diabetes mellitus type 1 and 2.
Studies were small, had potential risks of bias and apparent benefits increased with risk of bias. Overall the evidence was of low or very low quality and the authors state that it "does not provide a reliable indication of the likely effect". For oxycodone the authors found very low quality evidence showing its usefulness in treating diabetic neuropathy and postherpetic neuralgia only. One of the four authors declared receiving payments from pharmaceutical companies.More generally, a 2013 review examining the overall efficacy of opioid therapy for the treatment of neuropathic pain found studies were often subject to bias and that their efficacy and safety was not deducible with the evidence available. A 2017 Cochrane review examining opioid therapy as a treatment for many non-cancer pain syndromes (including neuropathic pain) concluded, "There was no evidence from randomised controlled trials to support or refute the use of opioids to treat chronic non-cancer pain in children and adolescents." Others
A 2016 Cochrane review of paracetamol for the treatment of neuropathic pain concluded that its benefit alone or in combination with codeine or dihydrocodeine is unknown.Few studies have examined whether nonsteroidal anti-inflammatory drugs are effective in treating peripheral neuropathy.There is some evidence that symptomatic relief from the pain of peripheral neuropathy may be obtained by application of topical capsaicin. Capsaicin is the factor that causes heat in chili peppers.