Case Presentation: A 44-year-old man previously healthy except sleep apnea syndrome presented with low grade fever and feeling of residual urine, but he returned home because of no evidences of urinary tract infection and incontinence. On the next day, he returned to ER with abdominal bloating and admitted, because abdominal CT showed paralytic ileus without any obvious obstruction. Prior to presentation, mexiletine hydrochloride was prescribed for three months due to atrial premature contraction. Two months later, eczema appeared all over and local dermatologist prescribed 30 mg corticosteroid QD, but two days later stopped immediately due to insomnia and irritability, and 2mg of risperidone QD was added. One week after admission, the amount of drainage from the gastric tube increased, the findings of abdominal X-ray got worsened, and blood tests showed hyponatremia suggesting SIADH. Further detailed medical history revealed ascending numbness from the distal extremities, sensory ataxia, orthostatic hypotension, and anhidrosis, which made a diagnosis of chronic intestinal paralysis due to autoimmune autonomic ganglionopathy. As a result of intravenous immunoglobulin and plasma exchange, self-defecation became possible one month after, and he was fully recovered.
Discussion: He started hospitalization with abdominal fullness, and the clinical course and symptoms seemed to be unusual for paralytic ileus and general constipation. Differential diagnosis of peristalsis depression was considered, including diabetes, amyloidosis, infectious diseases, heavy metals, Sjogren’s syndrome, paraneoplastic neuropathy and drugs, but none of the supporting findings including medical history, physical examination, or laboratory data were found. At the time of recognizing numbness of the extremities and disturbance of deep sense through interviews and examinations, we thought the sensory-autonomic polyneuropathy associated with autoimmune disorders. The patient showed various autonomic symptoms such as constipation, peristalsis disorder, orthostatic hypotension, anhidrosis, bladder rectal disorder, dry mouth, and limb numbness, in a subacute and progressive course. MRI examination confirmed that there was no abnormality in the central nervous system and spinal cord, and the nerve conduction studies showed the disappearance of F-waves in tibial nerve. Analysis of cerebrospinal fluid revealed 3 white cells per cubic millimeter（100％monocytes）, protein 228. Although prior infection was not remarkable, Guillain-Barre syndrome or autoimmune autonomic ganglionopathy(AAG) were suspected. Serum anti-α3gAChR antibody and anti-β4gAchR antibody were negative, however, almost half of AAG patients are reported to be seronegative. Although there are few reported cases of AAG and standard treatment for AAG has not been established, it is certain that some immune disorder might be involved due to remission by intravenous immunoglobulin and plasma exchange.
Conclusions: Although the pathophysiology of CIPO is various including neurogenic, myogenic or mesenchymogenic origins, inflammatory neuropathy like AAG affecting enteric nervous system is reported in some patients. If the patients with unusual clinical features showed seronegative for the diagnosis of AAG, there may still be some benefit from immunomodulatory therapy including plasmapheresis and intravenous gammaglobulin.