<unk>  (AFM) is a serious condition of the spinal cord. Symptoms include rapid onset of arm or leg weakness and decreased reflexes. Difficulty moving the eyes, speaking, or swallowing may also occur. Occasionally, numbness or pain may be present. Complications can include trouble breathing. The cause of most cases is unclear as of 2018. More than 90% of recent cases have followed a mild viral infection such as from enteroviruses. While polio can cause AFM, since 2014, it has not been involved in cases in the United States. The underlying mechanism involves damage to the spinal cord's grey matter. Diagnosis may be supported by medical imaging of the spine, nerve conduction studies, and cerebrospinal fluid testing. Treatment involves supportive care. Physical therapy may be recommended. Occasionally, mechanical ventilation is required to support breathing. Outcomes are variable. The condition is rare and occurs most commonly in children. Fewer than one in 500,000 children is affected per year in the United States. Although the illness is not new, an increase in cases has been seen since 2014 in the United States. In 2018, 233 cases were confirmed in the United States.
Acute flaccid myelitis
Vascular myelopathy
CMV polyradiculomyelopathy
Guillain–Barré syndrome
Subacute combined degeneration of spinal cord
Paraneoplastic cerebellar degeneration
Transverse myelitis
Amyotrophic lateral sclerosis