ICD-10-CM Book 2026 Edition

Chapters  /  Chapter 11  /  K55-K64

Other diseases of intestines (K55-K64)

K55 Vascular disorders of intestine
Excludes1 necrotizing enterocolitis of newborn (P77.-)
Excludes2 angioectasia (angiodysplasia) duodenum (K31.81-)
K55.0 Acute vascular disorders of intestine
Infarction of appendices epiploicae
Mesenteric (artery) (vein) embolism
Mesenteric (artery) (vein) infarction
Mesenteric (artery) (vein) thrombosis
K55.01 Acute (reversible) ischemia of small intestine
K55.011 Focal (segmental) acute (reversible) ischemia of small intestine
K55.012 Diffuse acute (reversible) ischemia of small intestine
K55.019 Acute (reversible) ischemia of small intestine, extent unspecified
K55.02 Acute infarction of small intestine
Gangrene of small intestine
Necrosis of small intestine
K55.021 Focal (segmental) acute infarction of small intestine
K55.022 Diffuse acute infarction of small intestine
K55.029 Acute infarction of small intestine, extent unspecified
K55.03 Acute (reversible) ischemia of large intestine
Acute fulminant ischemic colitis
Subacute ischemic colitis
K55.031 Focal (segmental) acute (reversible) ischemia of large intestine
K55.032 Diffuse acute (reversible) ischemia of large intestine
K55.039 Acute (reversible) ischemia of large intestine, extent unspecified
K55.04 Acute infarction of large intestine
Gangrene of large intestine
Necrosis of large intestine
K55.041 Focal (segmental) acute infarction of large intestine
K55.042 Diffuse acute infarction of large intestine
K55.049 Acute infarction of large intestine, extent unspecified
K55.05 Acute (reversible) ischemia of intestine, part unspecified
K55.051 Focal (segmental) acute (reversible) ischemia of intestine, part unspecified
K55.052 Diffuse acute (reversible) ischemia of intestine, part unspecified
K55.059 Acute (reversible) ischemia of intestine, part and extent unspecified
K55.06 Acute infarction of intestine, part unspecified
Acute intestinal infarction
Gangrene of intestine
Necrosis of intestine
K55.061 Focal (segmental) acute infarction of intestine, part unspecified
K55.062 Diffuse acute infarction of intestine, part unspecified
K55.069 Acute infarction of intestine, part and extent unspecified
K55.1 Chronic vascular disorders of intestine
Chronic ischemic colitis
Chronic ischemic enteritis
Chronic ischemic enterocolitis
Ischemic stricture of intestine
Mesenteric atherosclerosis
Mesenteric vascular insufficiency
K55.2 Angiodysplasia of colon
K55.20 Angiodysplasia of colon without hemorrhage
K55.21 Angiodysplasia of colon with hemorrhage
K55.3 Necrotizing enterocolitis
Excludes1 necrotizing enterocolitis of newborn (P77.-)
Excludes2 necrotizing enterocolitis due to Clostridium difficile (A04.7-)
K55.30 Necrotizing enterocolitis, unspecified
Necrotizing enterocolitis, NOS
K55.31 Stage 1 necrotizing enterocolitis
Necrotizing enterocolitis without pneumatosis, without perforation
K55.32 Stage 2 necrotizing enterocolitis
Necrotizing enterocolitis with pneumatosis, without perforation
K55.33 Stage 3 necrotizing enterocolitis
Necrotizing enterocolitis with perforation
Necrotizing enterocolitis with pneumatosis and perforation
K55.8 Other vascular disorders of intestine
K55.9 Vascular disorder of intestine, unspecified
Ischemic colitis
Ischemic enteritis
Ischemic enterocolitis
K56 Paralytic ileus and intestinal obstruction without hernia
Excludes1 congenital stricture or stenosis of intestine (Q41-Q42)
cystic fibrosis with meconium ileus (E84.11)
ischemic stricture of intestine (K55.1)
meconium ileus NOS (P76.0)
neonatal intestinal obstructions classifiable to P76.-
obstruction of duodenum (K31.5)
postprocedural intestinal obstruction (K91.3-)
Excludes2 stenosis of anus or rectum (K62.4)
K56.0 Paralytic ileus
Paralysis of bowel
Paralysis of colon
Paralysis of intestine
Excludes1 gallstone ileus (K56.3)
ileus NOS (K56.7)
obstructive ileus NOS (K56.69-)
K56.1 Intussusception
Intussusception or invagination of bowel
Intussusception or invagination of colon
Intussusception or invagination of intestine
Intussusception or invagination of rectum
Excludes2 intussusception of appendix (K38.8)
K56.2 Volvulus
Strangulation of colon or intestine
Torsion of colon or intestine
Twist of colon or intestine
Excludes2 volvulus of duodenum (K31.5)
K56.3 Gallstone ileus
Obstruction of intestine by gallstone
K56.4 Other impaction of intestine
K56.41 Fecal impaction
Excludes2 incomplete defecation (R15.0)
K56.49 Other impaction of intestine
K56.5 Intestinal adhesions [bands] with obstruction (postinfection)
Abdominal hernia due to adhesions with obstruction
Peritoneal adhesions [bands] with intestinal obstruction (postinfection)
K56.50 Intestinal adhesions [bands], unspecified as to partial versus complete obstruction
Intestinal adhesions with obstruction NOS
K56.51 Intestinal adhesions [bands], with partial obstruction
Intestinal adhesions with incomplete obstruction
K56.52 Intestinal adhesions [bands] with complete obstruction
K56.6 Other and unspecified intestinal obstruction
K56.60 Unspecified intestinal obstruction
K56.600 Partial intestinal obstruction, unspecified as to cause
Incomplete intestinal obstruction, NOS
K56.601 Complete intestinal obstruction, unspecified as to cause
K56.609 Unspecified intestinal obstruction, unspecified as to partial versus complete obstruction
Intestinal obstruction NOS
K56.69 Other intestinal obstruction
Enterostenosis NOS
Obstructive ileus NOS
Occlusion of colon or intestine NOS
Stenosis of colon or intestine NOS
Stricture of colon or intestine NOS
K56.690 Other partial intestinal obstruction
Other incomplete intestinal obstruction
K56.691 Other complete intestinal obstruction
K56.699 Other intestinal obstruction unspecified as to partial versus complete obstruction
Other intestinal obstruction, NEC
K56.7 Ileus, unspecified
Excludes1 obstructive ileus (K56.69-)
Excludes2 intestinal obstruction with hernia (K40-K46)
K57 Diverticular disease of intestine
CodeAlso if applicable peritonitis K65.-
Excludes1 congenital diverticulum of intestine (Q43.8)
Meckel's diverticulum (Q43.0)
Excludes2 diverticulum of appendix (K38.2)
K57.0 Diverticulitis of small intestine with perforation and abscess
Excludes1 diverticulitis of both small and large intestine with perforation and abscess (K57.4-)
K57.00 Diverticulitis of small intestine with perforation and abscess without bleeding
K57.01 Diverticulitis of small intestine with perforation and abscess with bleeding
K57.1 Diverticular disease of small intestine without perforation or abscess
Excludes1 diverticular disease of both small and large intestine without perforation or abscess (K57.5-)
K57.10 Diverticulosis of small intestine without perforation or abscess without bleeding
Diverticular disease of small intestine NOS
K57.11 Diverticulosis of small intestine without perforation or abscess with bleeding
K57.12 Diverticulitis of small intestine without perforation or abscess without bleeding
K57.13 Diverticulitis of small intestine without perforation or abscess with bleeding
K57.2 Diverticulitis of large intestine with perforation and abscess
Excludes1 diverticulitis of both small and large intestine with perforation and abscess (K57.4-)
K57.20 Diverticulitis of large intestine with perforation and abscess without bleeding
K57.21 Diverticulitis of large intestine with perforation and abscess with bleeding
K57.3 Diverticular disease of large intestine without perforation or abscess
Excludes1 diverticular disease of both small and large intestine without perforation or abscess (K57.5-)
K57.30 Diverticulosis of large intestine without perforation or abscess without bleeding
Diverticular disease of colon NOS
K57.31 Diverticulosis of large intestine without perforation or abscess with bleeding
K57.32 Diverticulitis of large intestine without perforation or abscess without bleeding
K57.33 Diverticulitis of large intestine without perforation or abscess with bleeding
K57.4 Diverticulitis of both small and large intestine with perforation and abscess
K57.40 Diverticulitis of both small and large intestine with perforation and abscess without bleeding
K57.41 Diverticulitis of both small and large intestine with perforation and abscess with bleeding
K57.5 Diverticular disease of both small and large intestine without perforation or abscess
K57.50 Diverticulosis of both small and large intestine without perforation or abscess without bleeding
Diverticular disease of both small and large intestine NOS
K57.51 Diverticulosis of both small and large intestine without perforation or abscess with bleeding
K57.52 Diverticulitis of both small and large intestine without perforation or abscess without bleeding
K57.53 Diverticulitis of both small and large intestine without perforation or abscess with bleeding
K57.8 Diverticulitis of intestine, part unspecified, with perforation and abscess
K57.80 Diverticulitis of intestine, part unspecified, with perforation and abscess without bleeding
K57.81 Diverticulitis of intestine, part unspecified, with perforation and abscess with bleeding
K57.9 Diverticular disease of intestine, part unspecified, without perforation or abscess
K57.90 Diverticulosis of intestine, part unspecified, without perforation or abscess without bleeding
Diverticular disease of intestine NOS
K57.91 Diverticulosis of intestine, part unspecified, without perforation or abscess with bleeding
K57.92 Diverticulitis of intestine, part unspecified, without perforation or abscess without bleeding
K57.93 Diverticulitis of intestine, part unspecified, without perforation or abscess with bleeding
K58 Irritable bowel syndrome
Includes irritable colon
spastic colon
K58.0 Irritable bowel syndrome with diarrhea
K58.1 Irritable bowel syndrome with constipation
K58.2 Mixed irritable bowel syndrome
K58.8 Other irritable bowel syndrome
K58.9 Irritable bowel syndrome, unspecified
Irritable bowel syndrome NOS
K59 Other functional intestinal disorders
Excludes1 change in bowel habit NOS (R19.4)
intestinal malabsorption (K90.-)
psychogenic intestinal disorders (F45.8)
Excludes2 functional disorders of stomach (K31.-)
K59.0 Constipation
Excludes1 fecal impaction (K56.41)
Excludes2 incomplete defecation (R15.0)
K59.00 Constipation, unspecified
K59.01 Slow transit constipation
K59.02 Outlet dysfunction constipation
K59.03 Drug induced constipation
UseAdditionalCode code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
K59.04 Chronic idiopathic constipation
Functional constipation
K59.09 Other constipation
Chronic constipation
K59.1 Functional diarrhea
Excludes1 diarrhea NOS (R19.7)
irritable bowel syndrome with diarrhea (K58.0)
K59.2 Neurogenic bowel, not elsewhere classified
K59.3 Megacolon, not elsewhere classified
Dilatation of colon
CodeFirst , if applicable (T51-T65) to identify toxic agent
Excludes1 congenital megacolon (aganglionic) (Q43.1)
megacolon (due to) (in) Chagas' disease (B57.32)
megacolon (due to) (in) Clostridium difficile (A04.7-)
megacolon (due to) (in) Hirschsprung's disease (Q43.1)
K59.31 Toxic megacolon
K59.39 Other megacolon
Megacolon NOS
K59.4 Anal spasm
Proctalgia fugax
K59.8 Other specified functional intestinal disorders
K59.81 Ogilvie syndrome
Acute colonic pseudo-obstruction (ACPO)
K59.89 Other specified functional intestinal disorders
Atony of colon
Pseudo-obstruction (acute) (chronic) of intestine
K59.9 Functional intestinal disorder, unspecified
K60 Fissure and fistula of anal and rectal regions
Excludes1 fissure and fistula of anal and rectal regions with abscess or cellulitis (K61.-)
Excludes2 abscess or cellulitis of anal and rectal regions (K61.-)
anal sphincter tear (healed) (nontraumatic) (old) (K62.81)
K60.0 Acute anal fissure
K60.1 Chronic anal fissure
K60.2 Anal fissure, unspecified
K60.3 Anal fistula
CodeFirst , if applicable:
Crohn's disease (K50.-)
ulcerative colitis (K51.-)
Excludes1 congenital fistula (Q43.6)
K60.30 Anal fistula, unspecified
Anal fistula NOS
K60.31 Anal fistula, simple
Low intersphincteric anal fistula
Superficial anal fistula
K60.311 Anal fistula, simple, initial
Anal fistula, simple, new
K60.312 Anal fistula, simple, persistent
Anal fistula, simple, chronic
K60.313 Anal fistula, simple, recurrent
Anal fistula simple, occurring following complete healing
K60.319 Anal fistula, simple, unspecified
K60.32 Anal fistula, complex
Extrasphincteric anal fistula
High intersphincteric anal fistula
Suprasphincteric anal fistula
Transsphincteric anal fistula
CodeAlso , if applicable:
perianal abscess (K61.0)
rectovaginal fistula (N82.3)
stenosis of anus and rectum (K62.4)
K60.321 Anal fistula, complex, initial
Anal fistula, complex, new
K60.322 Anal fistula, complex, persistent
Anal fistula, complex, chronic
K60.323 Anal fistula, complex, recurrent
Anal fistula complex, occurring following complete healing
K60.329 Anal fistula, complex, unspecified
K60.4 Rectal fistula
Fistula of rectum to skin
CodeFirst , if applicable:
Crohn's disease (K50.-)
ulcerative colitis (K51.-)
Excludes1 congenital fistula (Q43.6)
rectovaginal fistula (N82.3)
vesicorectal fistual (N32.1)
K60.40 Rectal fistula, unspecified
Rectal fistula NOS
K60.41 Rectal fistula, simple
Low intersphincteric rectal fistula
Superficial rectal fistula
K60.411 Rectal fistula, simple, initial
Rectal, fistula, simple, new
K60.412 Rectal fistula, simple, persistent
Rectal fistula, simple, chronic
K60.413 Rectal fistula, simple, recurrent
Rectal fistula simple, occurring following complete healing
K60.419 Rectal fistula, simple, unspecified
K60.42 Rectal fistula, complex
Extrasphincteric rectal fistula
High intersphincteric rectal fistula
Suprasphincteric rectal fistula
Transsphincteric rectal fistula
CodeAlso , if applicable:
perianal abscess (K61.0)
rectovaginal fistula (N82.3)
stenosis of anus and rectum (K62.4)
K60.421 Rectal fistula, complex, initial
Rectal fistula, complex, new
K60.422 Rectal fistula, complex, persistent
Rectal fistula, complex, chronic
K60.423 Rectal fistula, complex, recurrent
Rectal fistula complex occurring following complete healing
K60.429 Rectal fistula, complex, unspecified
K60.5 Anorectal fistula
CodeFirst , if applicable:
Crohn's disease (K50.-)
ulcerative colitis (K51.-)
Excludes1 congenital fistula (Q43.6)
K60.50 Anorectal fistula, unspecified
Anorectal fistula NOS
K60.51 Anorectal fistula, simple
Low intersphincteric anorectal fistula
Superficial anorectal fistula
K60.511 Anorectal fistula, simple, initial
Anorectal fistula, simple, new
K60.512 Anorectal fistula, simple, persistent
Anorectal fistula, simple, chronic
K60.513 Anorectal fistula, simple, recurrent
Anorectal fistula simple, occurring following complete healing
K60.519 Anorectal fistula, simple, unspecified
K60.52 Anorectal fistula, complex
Extrasphincteric anorectal fistula
High intersphincteric anorectal fistula
Suprasphincteric anorectal fistula
Transsphincteric anorectal fistula
CodeAlso , if applicable:
perianal abscess (K61.0)
rectovaginal fistula (N82.3)
stenosis of anus and rectum (K62.4)
K60.521 Anorectal fistula, complex, initial
Anorectal fistula, complex, new
K60.522 Anorectal fistula, complex, persistent
Anorectal fistula, complex, chronic
K60.523 Anorectal fistula, complex, recurrent
Anorectal fistula complex, occurring following complete healing
K60.529 Anorectal fistula, complex, unspecified
K61 Abscess of anal and rectal regions
Includes abscess of anal and rectal regions
cellulitis of anal and rectal regions
K61.0 Anal abscess
Perianal abscess
Excludes2 intrasphincteric abscess (K61.4)
K61.1 Rectal abscess
Perirectal abscess
Excludes1 ischiorectal abscess (K61.39)
K61.2 Anorectal abscess
K61.3 Ischiorectal abscess
K61.31 Horseshoe abscess
K61.39 Other ischiorectal abscess
Abscess of ischiorectal fossa
Ischiorectal abscess, NOS
K61.4 Intrasphincteric abscess
Intersphincteric abscess
K61.5 Supralevator abscess
K62 Other diseases of anus and rectum
Includes anal canal
Excludes2 colostomy and enterostomy malfunction (K94.0-, K94.1-)
fecal incontinence (R15.-)
hemorrhoids (K64.-)
K62.0 Anal polyp
K62.1 Rectal polyp
Excludes1 adenomatous polyp (D12.8)
K62.2 Anal prolapse
Prolapse of anal canal
K62.3 Rectal prolapse
Prolapse of rectal mucosa
K62.4 Stenosis of anus and rectum
Stricture of anus (sphincter)
K62.5 Hemorrhage of anus and rectum
Excludes1 gastrointestinal bleeding NOS (K92.2)
melena (K92.1)
neonatal rectal hemorrhage (P54.2)
K62.6 Ulcer of anus and rectum
Solitary ulcer of anus and rectum
Stercoral ulcer of anus and rectum
Excludes1 fissure and fistula of anus and rectum (K60.-)
ulcerative colitis (K51.-)
K62.7 Radiation proctitis
UseAdditionalCode code to identify the type of radiation (W88.-)
or radiation therapy (Y84.2)
K62.8 Other specified diseases of anus and rectum
Excludes2 ulcerative proctitis (K51.2)
K62.81 Anal sphincter tear (healed) (nontraumatic) (old)
Tear of anus, nontraumatic
UseAdditionalCode code for any associated fecal incontinence (R15.-)
Excludes2 anal fissure (K60.-)
anal sphincter tear (healed) (old) complicating delivery (O34.7-)
traumatic tear of anal sphincter (S31.831)
K62.82 Dysplasia of anus
Anal intraepithelial neoplasia I and II (AIN I and II) (histologically confirmed)
Dysplasia of anus NOS
Mild and moderate dysplasia of anus (histologically confirmed)
Excludes1 abnormal results from anal cytologic examination without histologic confirmation (R85.61-)
anal intraepithelial neoplasia III (D01.3)
carcinoma in situ of anus (D01.3)
HGSIL of anus (R85.613)
severe dysplasia of anus (D01.3)
K62.89 Other specified diseases of anus and rectum
Proctitis NOS
UseAdditionalCode code for any associated fecal incontinence (R15.-)
K62.9 Disease of anus and rectum, unspecified
K63 Other diseases of intestine
K63.0 Abscess of intestine
Excludes1 abscess of intestine with Crohn's disease (K50.014, K50.114, K50.814, K50.914,)
abscess of intestine with diverticular disease (K57.0, K57.2, K57.4, K57.8)
abscess of intestine with ulcerative colitis (K51.014, K51.214, K51.314, K51.414, K51.514, K51.814, K51.914)
Excludes2 abscess of anal and rectal regions (K61.-)
abscess of appendix (K35.3-)
K63.1 Perforation of intestine (nontraumatic)
Perforation (nontraumatic) of rectum
Excludes1 perforation (nontraumatic) of duodenum (K26.-)
perforation (nontraumatic) of intestine with diverticular disease (K57.0, K57.2, K57.4, K57.8)
Excludes2 perforation (nontraumatic) of appendix (K35.2-, K35.3-)
K63.2 Fistula of intestine
CodeAlso , if applicable, disruption of internal operation (surgical) wound (T81.32-)
Excludes1 fistula of duodenum (K31.6)
fistula of intestine with Crohn's disease (K50.013, K50.113, K50.813, K50.913,)
fistula of intestine with ulcerative colitis (K51.013, K51.213, K51.313, K51.413, K51.513, K51.813, K51.913)
Excludes2 fistula of anal and rectal regions (K60.-)
fistula of appendix (K38.3)
intestinal-genital fistula, female (N82.2-N82.4)
vesicointestinal fistula (N32.1)
K63.3 Ulcer of intestine
Primary ulcer of small intestine
Excludes1 duodenal ulcer (K26.-)
gastrointestinal ulcer (K28.-)
gastrojejunal ulcer (K28.-)
jejunal ulcer (K28.-)
peptic ulcer, site unspecified (K27.-)
ulcer of intestine with perforation (K63.1)
ulcer of anus or rectum (K62.6)
ulcerative colitis (K51.-)
K63.4 Enteroptosis
K63.5 Polyp of colon
Excludes2 adenomatous polyp of colon (D12.-)
inflammatory polyp of colon (K51.4-)
polyposis of colon (D12.6)
K63.8 Other specified diseases of intestine
K63.81 Dieulafoy lesion of intestine
Excludes2 Dieulafoy lesion of stomach and duodenum (K31.82)
K63.82 Intestinal microbial overgrowth
K63.821 Small intestinal bacterial overgrowth
K63.8211 Small intestinal bacterial overgrowth, hydrogen-subtype
K63.8212 Small intestinal bacterial overgrowth, hydrogen sulfide-subtype
K63.8219 Small intestinal bacterial overgrowth, unspecified
K63.822 Small intestinal fungal overgrowth
K63.829 Intestinal methanogen overgrowth, unspecified
K63.89 Other specified diseases of intestine
K63.9 Disease of intestine, unspecified
K64 Hemorrhoids and perianal venous thrombosis
Includes piles
Excludes1 hemorrhoids complicating childbirth and the puerperium (O87.2)
hemorrhoids complicating pregnancy (O22.4)
K64.0 First degree hemorrhoids
Grade/stage I hemorrhoids
Hemorrhoids (bleeding) without prolapse outside of anal canal
K64.1 Second degree hemorrhoids
Grade/stage II hemorrhoids
Hemorrhoids (bleeding) that prolapse with straining, but retract spontaneously
K64.2 Third degree hemorrhoids
Grade/stage III hemorrhoids
Hemorrhoids (bleeding) that prolapse with straining and require manual replacement back inside anal canal
K64.3 Fourth degree hemorrhoids
Grade/stage IV hemorrhoids
Hemorrhoids (bleeding) with prolapsed tissue that cannot be manually replaced
K64.4 Residual hemorrhoidal skin tags
External hemorrhoids, NOS
Skin tags of anus
K64.5 Perianal venous thrombosis
External hemorrhoids with thrombosis
Perianal hematoma
Thrombosed hemorrhoids NOS
K64.8 Other hemorrhoids
Internal hemorrhoids, without mention of degree
Prolapsed hemorrhoids, degree not specified
K64.9 Unspecified hemorrhoids
Hemorrhoids (bleeding) NOS
Hemorrhoids (bleeding) without mention of degree