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(DISEASES OF THE SMALL INTESTINE (Crohn’s Disease of the Small Intestine…
DISEASES OF THE SMALL INTESTINE
Mesenteric Ischemia
AMI
pain rapid in onset and severe
classic “pain out of proportion to physical exam,”
RFs: AF or severe atherosclerotic disease in other organ systems.
physical findings of peritonitis--> small bowel infarction has u already occurred and mortality high.
SMV thrombosis
more insidious onset
pain can be
diffuse and nonspecific
NOMI
minimal abdominal pain and frequently
overshadowed
by other complex medical problems resulting in nonocclusive ischemia.
predominant clinical feature of NOMI:
hemodynamic instability
(primary cause of this)
Congenital Abnormalities
Meckel’s Diverticulum
most common presenting illnesses:
obstruction, hemorrhage, inflammation
, and
umbilical fistula.
Hemorrhage presents w/
bright red or maroon blood per rectum, u painless, and is most common in infants under 2
Intestinal obstruction
volvulus
of small bowel around diverticulum
constrictive effect of a
mesodiverticular band
Intussusception
(diverticulum acting as a lead point): may present w/ a
palpable right-sided mass and passage of “currant jelly” stool.
closely mimics acute appendicitis
Less common complications: iron deficiency anemia, malabsorption, foreign body impaction, perforation, and incarceration in a hernia (Littre’s hernia), including inguinal, femoral, and umbilical herniae.
**Malrotation
surgical emergency: small bowel volvulus
Early symptoms include bilious emesis, with progression to distention, tenderness and shock being late findings due to irreversible necrosis**
Crohn’s Disease of the Small Intestine
common presenting
triad of Crohn’s: abdominal pain, diarrhea, and weight loss.
Waxing and waning severity common.
edema + fibrosis-->
partial obstruction
--> pain, nausea and vomiting, incr symptoms when higher residue foods consumed.
Bleeding uncommon
, in contradistinction to UC
Perianal involvement,
partic irregular and multiple anal fistulae
; Fissures and abscesses also occur; Perianal manifests most common in
colonic
involvement, although they can be seen in all
Extraintestinal manifestations: more common when colonic; Often respond to control of the underlying bowel disease.
Ocular
Skin (pyoderma gangrenosum, erythema nodosum)
joint (AS, hypertrophic osteoarthropathy, arthritis)
biliary (sclerosing cholangitis, pericholangitis, granulomatous hepatitis)
Vasculitis
- Aphthous stomatitis.
Nutritional losses
due to diminished oral intake and impaired
absorption,
partic w/ terminal ileal
disease.
Hypoalbuminemia, fat-soluble vitamins (A, D, E, and K), B12
gallstones frequent
in long-standing disease, due to
lithogenic bile
brought on by loss of terminal ileal bile salt reabsorption.
Growth retardation & developmental delays
common in younger patients.
some present with urgent issues such as acute bowel obstruction or abscess,
majority more indolent
RLQ
pain frequent (frequency of
ileocecal
involvement)
Small Bowel Obstruction
History
typical onset of acute SBO: colicky abdominal pain in periumbilical region; may become steadier as peristaltic activity lessens and generalized bowel distension progresses
begining to localize in a more somatic pattern: concern for bowel ischemia and peritonitis; Nausea and vomiting prominent in many, onset may be delayed in more distal obstructions
Abdominal distension also more prominent w/ distal obstruction
Constipation & (obstipation) may not be immediate given the potential for passage of air and stool already in the colon at the onset of illness.
Examination
typically present after a period of pain, often associated with nausea and vomiting, and
attendant fluid and electrolyte disturbance.
Auscultation: high-pitched sounds and rushes early in the illness; dearth of bowel activity is characteristic as distension progresses or peritonitis ensues.
In obese: areas of focal contour change, erythema, or tenderness near a surgical scar may be the only clue to bowel incarceration within an otherwise occult hernia.
Diffuse mild tenderness frequent
and often will improve after acute
decompression
via NG
impressive persistent tenderness
or more advanced peritoneal signs: prompt more urgent
surgical
intervention.
COLON, RECTUM, AND ANUS
Polyps and Carcinoma of the Colon and Rectum
Colorectal Polyp
u asymptomatic, but occasionally bleed enough; Most commonly detected during routine endoscopic surveillance.
Carcinoma of the Colon and Rectum
signs and symptoms determined largely by anatomic location
R colon
u exophytic lesions a. w/ occult blood loss--> iron deficiency anemia
May have a palpable right lower abdominal mass
1/3 of all new cases seen, most diagnosed at a late stage.
left and sigmoid colon: More frequently annular and invasive--> obstruction and macroscopic rectal bleeding
rectum: Rectal bleeding, obstruction, and, occasionally, alternating diarrhea and constipation. Tenesmus w/ far advanced disease.
Any >30 w/ a change in bowel habits, iron deficiency anemia, or rectal bleeding--> colonoscopy
If rectal bleeding occurs--> workup for a possible malignancy, even if apparent source a benign lesion (e.g., hemorrhoid) unless the patient is younger and rapidly responds to treatment.
Bright red rectal bleeding--> always be evaluated by an examination of perianal region and digital rectal exam.
ANUS AND RECTUM
Rectal Prolapse (Procidentia)
rectal pain or pressure, mild bleeding, incontinence, mucous discharge, and a wet anus
Rare: prolapse irreducible, ischemia results
prolapse commonly occurs after each bowel movement, must be manually reduced.
Hemorrhoids
Hemorrhoidal protrusion or bleeding.
Grades:
First-degree internal hemorrhoids do not prolapse;
anoscope must be used to visualize
Second-degree internal hemorrhoids prolapse w/ defecation and return spontaneously
Third-degree internal hemorrhoids prolapse w/ defecation and require manual reduction
Fourth-degree hemorrhoids non reducible
external hemorrhoids; Mixed hemorrhoids
Bleeding may be minimal, appearing only on toilet paper, or occasionally severe enough to cause anemia; u bright red, coats stool (rather than being mixed with it), and painless, unless there is thrombosis, ulceration, or gangrene.
Perianal Infections: Abscess and Fistula-in-Ano
Abscess
Except for early intersphincteric abscesses and supralevator abscesses, perianal pain and swelling readily apparent in perirectal abscesses. Spontaneous drainage of pus may occur.
cardinal signs of infection (pain, fever, redness, swelling, and loss of function) u present.
Fistula-in-Ano: manifest as chronic drainage of pus and sometimes stool from skin opening; rarely heal spontaneously, surgical correction indicated
Anal Fissures
secondary to local trauma, either from constipation or excessive diarrhea.
Pain typically starts w/ defecation, may persist from minutes to hours; disproportionate to size of lesion.
If bleeding present, u minimal and bright red.
gentle retraction of buttocks will reveal tear at anal verge
Rectal examination unnecessary & u a. w/ severe pain and significant sphincter spasm.
chronic recurrent anal fissures: classic triad of an external skin tag, a fissure exposing internal sphincter fibers, and a hypertrophied anal papilla at level of the dentate line is pathognomonic.
Anal Malignancy
Either type of malignancy may cause pain, bleeding, or a lump.
In cases of malignant melanoma, lymph node involvement and widespread metastases common at presentation. dx often delayed bc of lack of pigmentation of these lesions (amelanotic melanoma).
Examination should include palpation of inguinal lymph nodes, a site of potential metastasis.
Anorectal Sexually Transmitted Diseases
Benign Colonic Disorders
Diverticular Disease
Diverticulosis
Recurrent
abdominal
pain
, often localized to the
LLQ
, and
functional changes in bowel habits,
P/E unremarkable; fever & leukocytosis absent.
diverticulitis
depends on the progression of infection after the perforation
If perforation small, may spontaneously regress
If large, may be confined to pericolic tissues and abate after treatment with antibiotics.
may enlarge to form an extensive abscess, eventually requiring drainage.
may--> fistula formation.
Occasionally, diverticulum freely ruptures into peritoneal cavity--> peritonitis
1/6 of diverticulosis have diverticulitis.
hallmark symptoms: LLQ pain (subacute onset), alteration in bowel habits (constipation or diarrhea), occasionally a palpable mass, and fever.
Occasionally, free perforation w/ generalized peritonitis occurs, but
most common: localized
obstruction
secondary to repeated bouts of infl
Fistula formation may be a. w/ diarrhea
,
stool per vagina (colovaginal fi stula), pneumaturia and recurrent UTI (colovesical fi stula), or skin erythema with a furuncle rupturing and associated stool drainage (colocutaneous fistula).
life-threatening complications from diverticulitis:
44% involve perforation or abscess
, 8% involve fistula, and 4% involve obstruction
Diverticular Bleeding
profuse bright or dark red rectal bleeding
and
hypotension
.
Pxs w/ cancer unlikely to bleed as severely as pxs w/ diverticulosis, but carcinomas bleed more frequently
Colonic Obstruction and Volvulus
abdominal distension; cramping abdominal pain, u in hypogastrium; nausea and vomiting; and obstipation.
P/E: abdominal distension, tympany, high-pitched metallic rushes, and gurgles;
ileocecal valve
If incompetent--> signs and symptoms produced indistinguishable from those of routine small bowel obstruction.
If competent (75%)--> “closed loop” obstruction betw ileocecal valve & obstructing point distally--> Massive colonic distension, cecum may reach a diameter of 12 cm, incr possibility of perforation
complete large bowel obstruction: obstipation for 8-12; undergo emergent operation
partial large bowel obstruction: passage of some gas or stool; often NG decompression & IV fluids w/ resolution of acute obstruction. pxs can then be prepared for surgery by cleaning out large intestine, thus avoiding a colostomy.
Volvulus
Abdominal distension often massive; vomiting; abdominal pain; obstipation; and tachypnea.
P/E: distension, tympany, high-pitched tinkling sounds, and rushes
Ulcerative Colitis and Crohn’s Disease of the Colon
often have watery diarrhea that contains blood, pus, and mucus, accompanied by cramping, abdominal pain, tenesmus, and urgency.
Weight loss, dehydration, pain, and fever.
Fever u indicative of multiple microabscesses or endotoxemia secondary to transmural bacteremia.
55%: mild, indolent course;
30%: moderately severe that requires large doses of prednisone or sulfasalazine (Azulfidine) or other 5-ASA compounds;
15%: fulminant, life-threatening
fulminant presentation
often a. w/ massive colonic dilation secondary to transmural progression of disease & destruction of myenteric plexus (toxic megacolon).
severe constitutional symptoms related to sepsis, malnutrition, anemia, acid-base disturbances, and electrolyte abnormalities.
Extraintestinal manifestations occur in a small %: AS, peripheral arthritis, uveitis, pyoderma gangrenosum, sclerosing cholangitis, pericholangitis, and pericarditis.
P/E in quiescent phase: few or no findings; acute phase: acute abdomen