Constipation in Parkinson's disease.

Introduction

Constipation is a common problem in Parkinson's disease (PD), occurring in about 50–60% of patients and may occur even before the motor symptoms appear.[1] Various mechanisms causing it are degeneration of neurons in myenteric plexus of colon with presence of Lewy bodies, weakness and incoordinated contraction of muscles of pelvic floor and abdominal muscles which is unable to straighten, anorectal angle preventing passage of stool, dystonic contractions of muscles, megacolon and volvulus.[23]

Principles of management are the following. In early stages, simple measures may be tried, but later on, combinations may be needed.

Dietary modifications include increased intake of fluids (6–8 glasses of water/day), high fiber diet, and plenty of raw vegetables/salads, and bran can be added to increase the bulk.

Exercise should be increased.

Medicines that can be helpful include milk of magnesia, Cisapride, Mosapride (5HT4 agonist/partial 5HT3 antagonist), enemas, suppositories, stool softeners such as lactulose.

Pain/Dysesthesia in PD

Pain is a common problem in PD and occurs in about 50% of patients. It occurs both in early phase and in advanced stage of disease – more often in off period, but also in on period.[45]

The exact mechanism of pain and dysesthesia is not known, but several mechanisms are proposed. These are:[67] abnormal firing in afferent nerves in dystonic muscles, impaired ability of basal ganglia to modulate sensory information, alteration in serotonergic pathways, decreased activity of dopaminergic fibers on dorsal horn and intermediolateral column of spinal cord and reduced pain threshold due to dopamine deficiency by action on frontal, insular and cingulated gyrus (limbic system) and reduced nociceptive flexion reflex threshold by the same mechanism.

The presentation of pain/dysesthesia includes: painful “frozen shoulder” usually on the side of first symptom, especially before treatment is started (usually early in the disease), off-period limb pain, off-period painful foot dystonia, pain and dysesthesia on chest or abdomen. Some patients may have mechanical nerve root distribution pain/paresthesia coldness/numbness, arthritis and pain due to bursitis.

The management of these symptoms[8] is by introduction of dopaminergic therapy with dopamine agonist or levodopa, passive and active exercise and DBS (in advanced stages).