Lesion type	Causes
Autonomic or peripheral nerve	Autonomic neuropathy, diabetes mellitus, Guillain-Barré syndrome, herpes zoster virus, Lyme disease, pelvic fracture, pernicious anemia, poliomyelitis, radical pelvic surgery, sacral agenesis, spinal cord trauma, tabes dorsalis
Brain	Cerebrovascular disease, concussion, multiple sclerosis, neoplasm or tumor, normal pressure hydrocephalus, Parkinson disease, Shy-Drager syndrome
Spinal cord	Dysraphic lesions, intervertebral disk disease, meningomyelocele, multiple sclerosis, spina bifida occulta, spinal cord hematoma or abscess, spinal cord trauma, spinal stenosis, spinovascular disease, transverse myelitis, tumors or masses of conus medullaris or cauda equina