Disorders of the Small Intestines and Colon Flashcards
Normal digestion and absorption has 3 phases. What are they?
Intraluminal phase
Mucosal phase
Absorptive phase
Classified as a disruption of digestion and/or nutrient absorption
Malabsorption Disorders
Immune disorder caused by exposure to gliadin; abnormal immune
response to gluten
Loss of absorptive surface results in malabsorption
Antigenic stimulus from gluten causes formation of IgA antibodies directed against gliadin and tissue transglutaminase
More common in females (2:1)
Can present in infancy, but commonly ages 40-50
History of European ancestry
Often mistaken for IBS in adults
Also often mistaken for lactose intolerance
Celiac Disease
Consider what disease in any patient presenting with unexplained
deficiencies of iron, folate, Vitamin B12, non-specific GI complaints
celiac disease
What characteristic skin rash suggests Celiac Sprue?
Dermatitis herpetaformis
How is celiac disease diagnosed?
IgA endomysial ab, IgA tissue transglutaminase
Small bowel biopsy (confirmatory)
Clinical improvement on gluten-free diet
Congenital deficiency or absence of enzymes that border the lining of the stomach (lactase)
Appears in childhood and adulthood: Age of onset – typically age 6
Lactase Deficiency
Brush border enzyme, produced in the small intestines
Hydrolyzes lactose to glucose and galactose
Lactase
How is lactase deficiency diagnosed?
Lactose breast test
Lactose load test
Empirical trial of lactose elimination x 2 weeks
Refer to GI for confirmation: Hydrogen breath test, Stool acidity test
Literal dumping of stomach contents into proximal small intestine
Malabsorption due to surgery
Gastric emptying of liquids is more rapid – dilution of pancreatic
enzymes and bile acid in duodenum leads to mismatch of chyme
delivery and absorptive capacity
Decrease in pepsin secretion leads to bacterial overgrowth
Dumping Syndrome
There are minimal number of bacteria in small intestine
An overgrowth of the bacteria leads to malabsorption
Bacterial deconjugation of bile salts
Bacterial Overgrowth
Causative agent Tropheryma whippeli
Source unknown
Common in white men ages 40-60s
Fatal if not treated
Whipple Disease
What is the causative agent in Whipple Disease?
Tropheryma whippeli
How is Whipple disease diagnosed?
Duodenal biopsy - reveals infiltration of lamina propria with periodi acid-Schiff positive macrophages containing gram-positive bacilli
What is the treatment and monitoring for Whipple disease?
antibiotics - Ceftriaxone 1g IV BID or Meropenem 1g IV TID x 2 weeks followed by Bactrim DS BID x 12 months
Duodenal biopsy along with CSF PCR should be done every 6 months for at least a year
Most common causes of acute abdomen and abdominal surgical
emergency (most common operation in the US)
Peak incidence >20 years old
Should be considered in anyone with acute abdominal pain
Appendicitis
What is the cause of appendicitis?
Caused by obstruction of the appendix by:
Fecalith/appendicolith
Infectious process
Foreign body (calculi)
Parasitic worms
What are we concerned about with appendicitis?
Inflammation of the veriform appendix leads to necrosis and abscess
formation, and eventually peritonitis
Gangrene and perforation develop within 36 hours if untreated
What is the most common cause of appendicitis in children?
Hyperplasia
What is the most common cause of appendicitis in adults?
Fecalith
In appendicitis, what is the most common symptom and first to appear?
Anorexia
Which sign is described below that helps to diagnose appendicitis?
Pain on extension of right hip
+Psoas sign
Which sign is described below that helps to diagnose appendicitis?
Pain with internal rotation of right hip
+obturator sign
Which sign is described below that helps to diagnose appendicitis?
Pain in RLQ elicited with palpation of LLQ
+ Rovsing’s sign
What imaging is the gold standard for appendicitis?
CT – gold standard
What is the mortality rate for appendicitis?
Mortality <1% overall
Mortality can be as high as 20% in elderly patients
What is typically the cause of mortality in appendicitis cases?
Mortality comes from the complications, rare the actual appendicitis
Neurogenic failure or loss of peristalsis in the intestine without
mechanical obstruction
Acute Paralytic Ileus
What are some causes of acute paralytic ileus?
Post-surgical
Respiratory failure requiring intubation
Sepsis
Severe infections
DKA
Electrolyte disorders
What are some methods to diagnose acute paralytic ileus?
Plain abdominal xray: Gas-filled loops of small and large bowel
Air-fluid levels
Abdominal CT scan
Serum electrolytes
Note: may be difficult to distinguish ileus from partial small bowel obstruction on xray alone, need history and physical as well
What is the treatment for acute paralytic ileus?
Treat underlying cause
IV fluids 🡪 NPO
NG tube - Low suction, typically will resolve in several days
Avoid opioids and anticholinergics
What are some causes of small bowel obstructions?
Adhesions s/p surgery (most common)
Hernia
Intussuseption
Lymphoma
stricture
What is the most common cause of small bowel obstructions?
Adhesions s/p surgery
What xray finding would you see in a case of a small bowel obstruction?
Upright shows multiple air fluid levels and “step ladder” or “stack of coins” appearance
What is the treatment for small bowel obstruction?
True mechanical obstructions require surgery
In ED, attempt to remove excess air and bowel contents with nasogastric tube
IV fluid replacement and bowel rest
All require broad spectrum antibiotics prior to intervention - worry about perforation and contamination
Pouch in the wall of the lower part of the bowel
Most common congenital GI tract abnormality
Males = females
Complications more likely in males (50% of complications occur by age 2)
Meckel’s Diverticulum
What are some signs/symptoms of Meckel’s Diverticulum?
Bleeding (hematochezia) - painless
Intestinal obstruction
Intestinal volvulus
What testing is used to diagnose Meckel’s Diverticulum?
Technitium scan - Radio-opaque dye
Telescoping or invagination of a proximal portion of the bowel into a distal portion
Peristalsis acts to pull in more bowel, leading to constriction and edema
Hemorrhage may occur
Most commonly in the 3-12 month olds
Intussusception
Most frequent cause of intestinal obstruction in the infant
Intussusception
What are some signs/symptoms of Intussusception?
Currant jelly stools – 50% (Bloodly bowel movements with mucous
appear)
Severe, colicky pain
Tender, distended abdomen
Sausage-like abdominal mass in upper mid abdomen
Kids look sick, failure to thrive appearance
What percentage of adenocarcinomas are metastasized at the time of diagnosis?
80% are metastasized at the time of diagnosis
What is used to diagnose Intussusception and what would you expect to see?
Abdominal ultrasound - Target sign
What are some risk factors for Adenocarcinoma?
History of colorectal cancer
Hereditary nonpolyposis colorectal cancer
Peutz-jeghers syndrome
Familial adenomatous polyposis
Crohns disease
What are some risk factors/causes of Intussusception?
Meckel diverticulum
Intestinal polyps
Lymphomas
Cystic fibrosis
This tumor of the small intestine is aggressive and most commonly occurs in duodenum
Adenocarcinoma
How is small bowel adenocarcinoma diagnosed?
Can be seen with UGI with small bowel follow through
CT scan
Capsule endoscopy
Diagnosis confirmed by biopsy
What is the treatment for small bowel adenocarcinoma?
Surgical resection of early lesions cure 40%
Resection is also recommended for control of symptoms
Chemo may be used
Primary or secondary to disseminated disease
Most common site: Stomach and small intestines
Lymphoma
What is the most common type of lymphoma to disseminate to the stomach and small intestines?
Non-Hodgkins B cell lymphoma
What is the treatment for lymphoma of the small bowel?
Surgical resection
Surgical debulking
Chemo +/- radiation
A type of neuroendocrine tumor
Most frequent in the small intestines (ileum)
5 year survival rate is 50%
Usually found incidentally
Invasive growth or distant metastasis best indicator of prognosis
Carcinoid Tumors
What is the treatment for carcinoid tumors?
If confined to the small intestine – local excision (85% cure rate)
Palliative treatment for late disease
What are the signs/symptoms of carcinoid tumors?
Carcinoid syndrome (tumors secrete serotonin):
Flushing
Diarrhea
Hypotension
Most common cause of lower GI bleed
Diverticulosis
Saccular outpouchings of the colon – bulge at point of weakness from pressure
Commonly sigmoid and descending colon
Among the most common diseases in the US
Diverticulosis
What location is diverticulosis most common and why?
More common in sigmoid colon where intraluminal pressures are greatest
What is the etiology of diverticulosis?
Results from pressure that is exerted on the intestinal wall, leads to a bulge at a point of weakness, usually near to where an artery penetrates the muscular layer
May be associated with fiber-poor diets and people with connective tissue disorders
What is a complication of diverticulosis?
Diverticular hemorrhage develops in 5-15% of patients with diverticulosis
Diverticulitis
Inflammation of one or more diverticula
Occurs in 15-20% of patients with diverticulosis
Diverticulitis
What is the etiology of diverticulitis?
Fecalith or nuts/seeds in food: theory – feces/seed goes into pouch, sits and becomes infected
high intraluminal pressure 🡪 can lead to rupture or infection
What are some complications of diverticulitis?
Abscess
Perforation
Peritonitis
Intestinal obstruction
Fistula
Chronic stricture
What is the treatment for diverticulitis?
Most require hospitalization, especially elderly
Clear liquid diet (bowel rest), slow advance of bland diet
IV fluids – rehydration
Antibiotics: Cipro BID & Flagyl TID for 7 to 10 days – gold standard
Pain control
Surgical resection of the infected area
Antibiotic associated diarrhea – current or prior use within 3 months
Significant clinic problem almost always caused by C. difficile
Hospitalized patients and those in chronic care facilities are the most susceptible
Transmitted easily from patient to patient by hospital personnel
Toxin-mediated disease
Pseudomembranous Colitis
What are some causative antibiotics for Pseudomembranous Colitis?
Aminopenicillins
Clindaymycin
Cephalosporins (2nd and 3rd generation)
Fluroquinolones
What is the treatment for Pseudomembranous Colitis?
d/c broad spectrum antibiotic therapy - Diarrhea will resolve in 15-20% of patients
Drug of choice – Flagyl (500mg PO TID x 14 days)
Vancomycin – severe disease (Severe = WBC >15000, Cr >1.5 times
baseline)
Avoid antimotility agents and narcotics (May delay the clearance of the toxins)
+/- enema if underlying ileus, megacolon, or shock
Approximately what percentage of pseudomembranous colitis patients
relapse?
Approximately 20% of patients
What is the reason/cause for the pseudomembranous colitis patients
relapse?
Recurrence is from germination of spores persisting in the colon or
reinfection
Why is PO Vancyomycin used in pseudomembranous colitis instead of IV Vancyomycin?
IV vancomycin does NOT penetrate the bowel
Idiopathic, chronic inflammatory disease
Diffuse mucosal inflammation
Involves the rectum
May extend proximally in a continuous fashion to involve part or all of the colon
Ulcerative Colitis
Describe the peak incidence of ulcerative colitis?
Bimodal incidence: first peak 20-30 year olds, second peak 50-70 year
olds
Most commonly diagnosed in late adolescence and early adulthood
Mean age: 43-55 year old
Disease is less severe in UC patients who also do what?
Smoking protects against UC
Disease less severe in smokers
What is the pathophysiology of ulcerative colitis?
Inflammation begins in the distal rectum and spread proximally –
continuous lesion
Crypt architecture is distorted
Mucosal vascular congestion with edema and focal hemorrhage may
be present
Neutrophils invade the epithelium, usually in crypts 🡪 cryptitis and
ultimately, crypt abscess
Results in a diffuse friability and erosions with bleeding
In ulcerative colitis, what is always involved?
the rectum
What is the hallmark finding of ulcerative colitis?
Bloody diarrhea with mucous – HALLMARK finding
What is the key to diagnosing ulcerative colitis?
Colonoscopy – key to diagnosis
What is the mainstay of medical management of ulcerative colitis?
Sulfasalazine – mainstay of Rx
Antibacterial and anti-inflammatory therapy
In patients taking Sulfasalazine, what supplement is needed?
Impairs folate absorption – need folate replacement
Which medication is added on to Sulfasalazine in moderate to severe cases of ulcerative colitis?
Glucocorticoids
In ulcerative colitis patients, approximately what percentage will have surgery within 10 years of diagnosis?
50%
What is the surgery of choice in ulcerative colitis?
Operation of choice - Single stage total proctocolectomy with ileostomy
Why is surgical management used in treating ulcerative colitis?
Surgery is CURATIVE
What are some complications of ulcerative colitis?
Toxic megacolon <2% (50% mortality)
Perforation
Cancer (34% risk of colon cancer after 30 years of disease)
Extreme dilation and immobility of the colon
Surgical emergency
Toxic Megacolon
What is the mortality rate of a toxic megacolon?
Mortality rates of 15-50%
What other conditions is toxic megacolon associated with?
Associated with ulcerative colitis (may be the presenting sx of UC,
usually presents early in the disease)
Crohns disease
Amoebic colitis
Pseudomembranous colitis
Infections (shigella, C. diff, Clostridium)
What is the treatment for toxic megacolon?
Emergent surgery (resection)
Initial therapy is medical, patients at risk for perforation
IV fluids
Colon decompression
Also called Acute Colonic Pseudo-obstruction or acute megacolon
Type of megacolon
Significant cecal dilatation
At risk for spontaneous perforation
Post-surgical or medical patients who are severely ill or have malignancy
Must rule out ischemia or obstruction
Ogilvie Syndrome
Sudden, twisting of the bowel on itself leading to obstruction and ischemia
Small bowel twists around the superior mesenteric artery, leads to kinking of the duodenum –> Results in reduced blood supply to the midgut 🡪 ischemia and necrosis of the bowel
Gangrene, necrosis, and perforation can occur
Increased incidence in elderly and patients with other comorbidities
Volvulus
What are the two most common sites for Volvulus?
Cecum
Sigmoid colon
What percentage of cases of Volvulus present less than one month of age?
> 50% present less than one month of age
What are some causes of volvulus?
Idiopathic
Anomaly of rotation
ingested foreign body
Adhesions
If you see a “double bubble” sign on an Xray, what should you suspect?
Volvulus
What is the treatment for a volvulus?
Endoscopic reduction if stable
Surgical repair: If patient has peritonitis – exploratory laparotomy and
resection with diverting colostomy
Congenital absence of autonomic smooth muscle ganglia
Aganglionic bowel segment contracts but needed relaxation does not occur which leads to stasis of stool and constipation
Hirschsprung Disease
In Hirschsprung Disease, what location is most commonly affected?
90% occur in rectosigmoid area
Can affect the entire colon
Most common cause of lower GI obstruction in neonates (blockage due to improper nerve impulses to muscle movement)
Hirschsprung Disease
Hirschsprung Disease coexists with what other anomalies?
Down Syndrome
What is the typical initial presentation of Hirschsprung Disease?
No first bowel movement (meconium) within 24-48 hours of birth
Stool: small, ribbon-like
Appearance: chronically ill
Anal tone: tight
Rectum: empty
Soiling: rare
What is the gold standard for diagnosing Hirschsprung Disease?
Rectal biopsy
What is the treatment for Hirschsprung Disease?
Mild - fiber
More severe - May involve 1 or 2 surgeries
A chronic, recurrent disease; lifelong illness
Patchy, transmural inflammation (skip lesions) involving any segment of the GI tract from
mouth to anus
Incidence: 5 per 100,000 in the US
In 10% of cases, it may be impossible to distinguish from UC – much overlap exists
Crohn’s Disease
What is the incidence of Crohn’s Disease?
Bimodal incidence: first peak 20-30 year olds, second peak 50-70 year olds
Most commonly diagnosed in late adolescence and early adulthood
Mean age: 33-45 year old
What can exacerbate Crohn’s Disease?
Cigarette smoking increases the risk of Crohns
NSAIDs exacerbate
What is the involvement of Crohn’s Disease?
Can involve anywhere along the entire GI tract (mouth to anus)
Rectum is often spared
Involvement with UGI tract is rare
What is the pathophysiology of Crohn’s Disease?
Initial lesions are aphthoid ulcers and focal crypt abscess – stellate ulcerations fuse longitudinally and transversely, demarcating normal islands of mucosa
Form noncaseating granulomas from mucosa to serosa
Submucosal or subseroal lymphoid aggregates
Transmural inflammation is accompanied by fissures – may form fistulous tracts or abscesses
“skip lesions”
What are some extraintestinal complications of Crohn’s Disease?
Oral aphthous ulcers (earliest manifestation)
Increased prevalence of gallstones due to malabsorption of bile salts from the terminal ileum
Acute arthropathy
Ocular manifestations (uveitis)
Nephrolithiasis
Erythema nodosum
Pyoderma gangrenosum
Uncommon inflammatory ulcerative skin disease
Affects less than 10% of IBD patients
Occurs more often with UC than Crohns
Seriousness of skin ulcer does not correlation to seriousness of IBD
Pyoderma Gangrenosum
A classic skin condition associated with Crohns
Presents as tender red nodules (usually on the shins)
Causes fever and joint pain
Usually resolves in 3-6 weeks
Erythema Nodosum
What two labs can help differentiate between Crohns and UC?
Antisaccharomyces cerevisiae antibodies (ASCA) and antineutrophil cytoplasmic antibodies (pANCA)
ANCA +: freq in UC, rare in Crohns
ASCA +: rare in UC and freq in Crohns
*must be interpreted with clinical findings and other diagnostic results
What is the gold standard for diagnosing Crohns disease?
Colonoscopy – gold standard for diagnosis
What are some complications of Crohns disease?
Abscess – 20%
Strictures
Intestinal narrowing
Fistulas – 40%
Malabsorption
Perianal disease
Increased risk for developing colorectal carcinoma – small bowel adenocarcinoma
What is the medical mainstay of treatment for Crohns disease?
Sulfasalazine – mainstay of Rx
Antibacterial and anti-inflammatory therapy
What are the surgical management guidelines for Crohns disease?
Surgery is not CURATIVE - You cannot resect all of the bowel since it is mouth to anus
With small bowel disease, resect as little intestine as possible
Will need surgery for intractability, fulminant or anorectal disease
If more than 50cm of what is resected, patient needs monthly B12
injections
ileum
Condition that is secondary to removal of small intestines:
Crohns resection
Mesenteric infarct
Tumor resection
Short Bowel Syndrome
Chronic (>6months) functional bowel disorder
Symptoms are not explained by structural or biochemical abnormalities
Recurrent abdominal pain, alterations in bowel habits
Associated with history of depression/anxiety – 50%
Irritable Bowel Syndrome
Definition: abdominal pain/discomfort with two of the three features:
Relieved with defecation
Onset associated with change in frequency of stool
Onset associated with change in form of stool
Irritable Bowel Syndrome
What are some causes of Irritable Bowel Syndrome?
Evidence shows physiologic disturbances occur in the majority
of patients - Abnormal visceral perception or extraintestinal motor dysfunction
Bacterial overgrowth
Psychological
Diet
Infection
In potential cases of irritable bowel syndrome, the presence of these symptoms suggest other diagnoses
Acute onset
>40 years of age
Severe constipation or diarrhea
Nocturnal diarrhea (never normal)
Hematochezia
Weight loss
Fevers
Family history of cancer, inflammatory bowel disease, celiac disease
What are the three main branches of abdominal aorta?
celiac artery
superior mesenteric artery
inferior mesenteric artery
Injury ranges from reversible to transmural bowel necrosis
Persistent vasoconstriction causes progression of ischemic injury despite relief measures if not corrected quickly
Intestinal ischemia
Abdominal pain mostly postprandial
Weight loss secondary to above
Results from occlusion of major mesenteric vessel or non-occlusive disease
Usually 2-3 visceral vessels affected before symptoms develop
Visceral artery insufficiency (“intestinal angina)
What are the types of ischemic bowel disease?
Colon ischemia (60%)
Acute mesenteric ischemia (30%)
Focal segment ischemia (5%)
Chronic mesenteric ischemia (5%)
Which type of ischemic bowel disease is described below?
Mainly occurs in IMA distribution
Secondary to reduction in blood flow
Can happen post-op
Non-occlusive
Colonic mucosa will slough secondary to under-perfusion
Abdominal cramping followed by rectal bleed
Ischemic Colitis
Which type of ischemic bowel disease is described below?
Challenging diagnosis
Hypo-perfusion of bowel vasculature
Increasing incidence in western countries parallels atherosclerosis and aging population
> 50 year olds
Think of mesenteric ischemia if an elderly patient presents with an acute abdomen
A high index of suspicion is vital to detect them earlier and minimize morbidity and mortality
Acute Mesenteric Ischemia
What are some risk factors for acute mesenteric ischemia?
Atrial fibrillation
History of MI
Valvular heart disease
Peripheral artery disease
Abdominal pain out of proportion to PE findings – sudden and severe
onset should raise your suspicion for what?
acute mesenteric ischemia
What is the prognosis for acute mesenteric ischemia?
10-15% mortality and morbidity rate from surgical intervention
Without intervention, acute and chronic intestinal ischemia are fatal
