Bowel obstruction Flashcards
What parts make up the small intestine
Duodenum
Jejunum (40%)
Ileum (60%)
What supplies the small intestine
Vascular: SMA
Innervation: ANS
What is the sequence of the large bowel
Cecum Ascending colon (hepatic flexure) Transverse colon (splenic flexure) Descending colon Sigmoid Rectum
What supplies the large bowel
Vascular: SMA and IMA
Innervation: ANS
What is the physiologic role of the small intestine
Digestion with absorption of water, electrolytes, and nutrients
- intestinal motility mixes, propels, and stores enteric contents
- reabsorbs 80% of fluids
- affected by hormones, drugs, toxins, and disease
- transit time is 4 hours
What is the physiologic role of the large bowel
Absorbs water and electrolytes from liquid stools, mostly right colon
- stores feces in the left colon
- transit time is 18-48 hours
- affected by emotions, diet, disease, infection, and bleeding
What studies help you visualize bowel obstruction
KUB (3 way abd xr)- A/P supine, upright, PA chest
CT abdomen (use water soluble contrast)
Small bowel follow through w/o UGI
US not as helpful as CT
KUB allows you to visualize
Gas patterns; SBO vs LBO vs Ileus
What causes a SBO
Normal flow of intestinal contents is interrupted (adhesions, volvulus, intussusception, tumors, FB, gallstones)
MCC worldwide is hernias, but MCC in US is adhesions!
What are adhesions
Fibrous bands of scar tissue that bind tissue or organs
Occur 2/2 inflammatory process or injury )diverticulitis, appendicitis, PID, endometriosis)
Cause obstruction by extrinsic compression
What is intestinal volvulus
Bowel twists on itself causing a closed loop obstruction
What is intussusception
Telescoping of the bowel on itself
What happens to the intestine after obstruction
Proximal to obstruction: bowel dilates
Swallowed air and gas from bacteria worsen dilation
Bowel walls become edematous 2/2 loss of absorptive fxn
Fluid can extravasate into abdomen (fluid loss)
What does strangulation of bowel cause
pressure inside the bowel= compromised perfusion, ischemia, necrosis, sepsis
Fluid loss is 2/2
vomiting
decreased absorption
third space loss
-all lead to dehydration!
What history points you to different Dx
Abdominal distention: distal obstruction
Vomiting: proximal obstruction
Feculent smelling emesis: bacterial overgrowth
What is the difference between constipation and obstipation
Constipation: passing flatus but not stool
Obstipation: Can’t pass flatus or stool
Exam findings that indicate SBO are
Patient in distress 2/2 abd pain and dehydration
Tachycardia
DMM
inspect for surgical scars and hernias
Abdominal distention (tympanic w/ increased air, dull w/ ascites)
Diffuse abd ttp (rebound and pt still? think strangulation)
What are bowel sounds like in SBO
Early dz: high pitched rushes
Late: abdomen silent
Plain films can show you
Dilated bowel proximal to obstruction with collapse distally Air fluid levels Closed loop obstructions (high risk strangulation) Free air (perforation)
How do you manage SBO initially
IVF
Correct metabolic abnormalities
Assess need for surgery
How do you manage a partial SBO
IVF, decompression of stomach with NG tube (take air OUT)
follow labs (CBC, electrolytes, UA) and UO
Monitor for signs of strangulation
-Most resolve w/ conservative management
How do you manage complete SBO or SBO w/ hernia
OR! need laparotomy to mobilize adhesions/repair hernia; resect ischemic bowel
Complications of SBO are
wound infection anastomosis leak abscess peritonitis fistula formation short bowel syndrome w/ extensive resection
What is paralytic ileus
decreased bowel motility 2/2 systemic or inflammatory process
bowel becomes distended w/o mechanical obstruction
Caused by: narcotics, bedrest, trauma, hypothyroid, electrolyte abnormalities, anesthesia, sepsis
Biggest differences between SBP and paralytic ileus
SBO: crampy abdominal pain, gas on small intestine only
PI: minimal abdominal pain, gas in small and large bowel
How do you diagnose paralytic ileus
Plain films: diffuse bowel dilation involving small and large bowel
How do you treat paralytic ileus
NPO
NG tube
IVF
most resolve in 4 days
What are the MCC of LBO
Adenocarcinoma* Scarring Volvulus -also, IBD, FB, fecal impaction -RARE to see adhesions causing LBO!
Where do LBO occur most often
Sigmoid colon
How do LBO present
Crampy abdominal pain
abdominal distention
nausea, vomiting
obstipation
On PE for LBO you may find
Abdominal distention w/ tympany
high pitched rushes and gurgles (BS)
Localized, tender palpable mass (if strangulated closed loop)
What will diagnostics of LBO show
Plain films: distended proximal colon, air fluid levels, NO air in rectum
What is a distinguishing factor in diagnosing LBO
competence of ileocecal valve!
If competent, can create a closed loop obstruction causing massive dilation of cecum (>12 cm) w/ increased risk of perforation
Where does volvulus occur most
Sigmoid colon!
Can also be seen in cecum
Will note massive abdominal distention w/ abdominal pain, vomiting, and obstipation
What shows you the exact location of volvulus
barium enema!
Will see “birds beak”
How do you manage volvulus
Partial LBO: trial conservative therapy (NG tube, IVF, prep colon for surgery)
Complete: laparotomy
May be reduced w/ sigmoidoscopy!**
Complications of sigmoidoscopy are
perforation
peritonitis
sepsis
-If perforation occurs, immediate laparotomy w/ resection of bowel and diverting colostomy
What are the primary Sx of rectal disease
pain
bleeding
discharge
What is the dentate line
Anorectal junction;
Above: columnar epithelium, no sensation just pressure
Below: squamous epithelium, VERY sensitive
What are hemorrhoids
normal vascular structures in the anal canal arising from a plexus of dilated superior and inferior veins
What causes hemorrhoids
Prolonged sitting, straining
Pregnancy, advanced age, increased pelvic pressure, portal HTN, diarrhea, constipation
How do you classify hemorrhoids
Internal: above dentate line
External: below dentate line
Primary Sx of hemorrhoids are
Bleeding (bright red)
Pruritis
Prolapse
Pain 2/2 thrombosis
What are first degree hemorrhoids and how do you treat them
Bulge in anal canal, do not protrude
ASx so just treat w/ bulking agents (fiber) and increase water intake to avoid constipation
If Sx, infrared coagulation* or rubber band ligation work
What are second degree hemorrhoids
Protrusion w/ defecation, reduce spontaneously
Treat like 1st degree! ASx fiber and fluids, Sx coagulate ot ligate
What are third degree hemorrhoids and how do you treat them
Protrude with defecation, need to be reduced manually
Rubber band ligation or surgical hemorrhoidectomy bc non-surgical Tx are not really effective
What are fourth degree hemorrhoids and how do you treat them
Protrude permanently, incarcerated
Surgical hemorrhoidectomy
How do you manage external hemorrhoids
Symptomatic management, unless thrombosed
What are thrombosed hemorrhoids
blood clot in a hemorrhoid, cause severe perianal pain
Usually self limited and resolve in 7-10 days
How do you treat thrombosed hemorrhoids
Sitz bath
mild analgesics
Hydrocortisone suppository or foam
If seen in first 24-48 hrs, evacuate under local anesthesia
How do you visualize anal polyps and anal cancer
Use an anoscope! Like a speculum for your anus
Where do you refer patients if you are concerned about anorectal problems
a colorectal specialist
GI will just refer them there anyways
What is an abscess
infected pocket 2/2 obstruction of perianal glands (between external and internal sphincter)
Intersphenteric and Supralevator are not palpable on PE
Perianal and Ischiorectal are palpable on PE
How do abscesses present
perianal pain and swelling
Spontaneous drainage of pus
Fever, redness, swelling
How do you treat an abscess
Drain (I&D best in OR to avoid damaging the anal sphincter)
Antibiotics
this is a serious infection!!
What is a fistula-in-ano
Chronic perianal infection occurring after drainage of a perirectal abscess Abnormal connection between anus at dentate line and perianal skin
Causes pus drainage +/- stool drainage
they do NOT heal spontaneously
What must you r/o if you see an anal fistula
Crohn’s disease!
How do you treat anal fistulas
Fistulotomy: unroofing of fistula and allowing it to heal by secondary intention
Avoid damaging the large portion of the sphincter muscle and prevent incontinence
What are anal fissures
Linear tears in the lining of the anal canal below the dentate line
MC posteriorly
MCC of severe anorectal pain
Caused by trauma: constipation or severe diarrhea
How do anal fissures present
pain worse during BM and associated with bright red streaking blood in stool
Pain disproportionate to size of fissure
With anal fissures, what may you note on PE
External skin tags
sphincter spasm 2/2 pain
How do you manage anal fissures
Avoid constipation or diarrhea
Bulk laxatives (fiber helps constipation and diarrhea)
Mild analgesics
Sitz bath
Nitroglycerin or Diltiazem cream (small amt to minimize ADE)
Chronic: surgery, lateral internal sphincterotomy
What is rectal prolapse
Mass protruding through anus occurring initially w/ BM then retracting (can make dx based on hx too)
Associated with chronic constipation, chronic straining, pregnancy, Hx of surgery
How do you manage rectal prolapse
Prevent constipation
Refer to colorectal surgeon
What is a rectocele
Fascia weakens allowing rectum to bulge into vagina
