ICD-10-CM > K00-K95 > K55-K64 > K59 K59 Other functional intestinal disorders Non-Billable/Non-Specific Type 1 Excludes change in bowel habit NOS (R19.4)intestinal malabsorption (K90.-)psychogenic intestinal disorders (F45.8) Type 2 Excludes functional disorders of stomach (K31.-) Codes K59.0ConstipationK59.00Constipation, unspecifiedK59.01Slow transit constipationK59.02Outlet dysfunction constipationK59.03Drug induced constipationK59.04Chronic idiopathic constipationK59.09Other constipationK59.1Functional diarrheaK59.2Neurogenic bowel, not elsewhere classifiedK59.3Megacolon, not elsewhere classifiedK59.31Toxic megacolonK59.39Other megacolonK59.4Anal spasmK59.8Other specified functional intestinal disordersK59.81Ogilvie syndromeK59.89Other specified functional intestinal disordersK59.9Functional intestinal disorder, unspecified