Abdominal Surgery- Intestines Part B Flashcards
Diverticular Disease
- encompasses a set of colonic pathologies that result from abnormal outpouchings of the colonic mucosa (diverticula).
Diverticula
blind pouches that protrude from the gastrointestinal wall and communicate with the lumen
Diverticulosis
the presence of multiple colonic diverticula without evidence of infection
Diverticulitis
inflammation or infection of colonic diverticula
Diverticular Disease
Epidimeology
∼ 50% of individuals > 60 years have diverticulosis
Diverticular Disease Etiology
Caused mainly by lifestyle and environmental factors
- Diet (low-fiber, rich in fat and red meat)
- Obesity
- Low physical activity
- Increasing age
Diverticulitis Pathophysiology
Most commonly:
- chronic inflammation and increased intraluminal pressure →
- erosion of diverticula wall →
- inflammation and bacterial translocation
Rarely:
- stool becomes lodged in diverticula →
- obstruction of intestinal lumen → inflammation
Diverticulosis Clinical Features
- Usually asymptomatic
- may have abdomincal discomfort
- chronic constipation
Diverticulitis Clinical Features
- Low-grade fever
- Sigmoid colon most commonly affected → left lower quadrant pain
- Possibly tender, palpable mass (pericolonic inflammation)
- Change in bowel habits
- (constipation in ∼ 50% of cases and diarrhea in 25–35% of cases)
- Nausea and vomiting
Elderly or immunocompromised milder symptoms
Symptomatic Diverticulosis Diagnosis
Colonoscopy- modality of choice
Diverticulitis Diagnotics
Laboratory studies
- leukocytosis; possible anemia
Imaging
-
CT abdomen and pelvis with IV contrast
- Preferred initial imaging modality
- Bowel wall thickening > 3 mm
- Screening colonoscopy
- 6–8 weeks after acute episode to assess and rule out malignancy
- Contraindicated during an acute episode because of the increased risk of perforation.
Diverticulitis Tx Aproach
Uncomplicated diverticulitis
- Conservative management
- Consider broad-spectrum oral antibiotics (e.g., ciprofloxacin PLUS metronidazole)
Complicated diverticulitis
- broad-spectrum IV antibiotics
- CT-guided percutaneous drainage for abscesses > 4 cm
- Emergency colectomy in patients with generalized peritonitis
Uncomplicated vs Complicated Diverticulitis
Uncomplicated diverticulitis: localized inflammation of a colonic diverticulum with no evidence of complications
Complicated diverticulitis: inflammation of a colonic diverticulum associated with
- perforation,
- abscess,
- fecal peritonitis,
- bowel obstruction,
- fistula formation
Uncomplicated DIverticulitis Tx
Mild diverticulitis is more likely to be an inflammatory process rather than an infectious one. The selective administration of antibiotics is a conditional recommendation.
- MetronidazolePLUS one of the following
- Ciprofloxacin
- Levofloxacin
Complicated Diverticulitis Tx
Antibiotic therapy: broad-spectrum IV antibiotics
- Metronidazole PLUS one of the following
- Ciprofloxacin
- Levofloxacin
Management of complications
- Abscess Size ≥ 4 cm
- Ultrasound- or CT-guided percutaneous drainage
- Perforation with generalized peritonitis;
- emergency surgery
Elective colectomy
- Routinely recommended 6–8 weeks after resolution of complicated diverticulitis
Prevention of Diverticulitis
- High-fiber diet
- Fluid hydration
- Vigorous physical activity
Complications of Diverticular Disease
- GI Bleeding
- Fistulas
- Inflammtions (diverticulitis)
- Abscess
- Perforation
- Intestinal Obstruction
Diverticular Disease Fistulas
Colovesical (most common)
Symptoms : Pneumaturia and fecaluria
Volvulus
twisting of a loop of bowel on its mesentery
Volvulus Epidimiology
Incidence
- Volvulus: 3rd most common cause (∼ 10–15%) of intestinal obstruction in the United States
- Sigmoid volvulus (most common, 80%)
Age and sex
- Sigmoid volvulus: ∼ 70 years
- Cecal volvulus: 40–60 years
- Intestinal malrotation and midgut volvulus: neonates and infants
Vovulus Risk Factors
- Long mesentery
- Acquired (sigmoid volvulus): chronic constipation
- Congenital (cecal volvulus): abnormally mobile cecum
- Intestinal malrotation
- Megacolon
- Intestinal bands/adhesions
Sigmoid Volvulus Clinical Features
- abdominal pain, which decreased after explosive passage of stool/gas
- Slowly (most common) or rapidly progressive symptoms of bowel obstruction
- peritonitis
Sigmoid Volvulus Tx
- IV fluids; NPO; placement of a nasogastric tube
- Evaluation
- No signs of peritonitis: rigid/flexible sigmoidoscopic detorsion of the volvulus
- Signs of peritonitis→ broad-spectrum IV antibiotics and emergency surgery
- Surgery
Sigmoid Vovlus Surgery
Sigmoid colectomy and primary anastomosis :
- indicated in hemodynamically stable patients with viable bowel
Hartmann procedure:
- resection of the rectosigmoid colon followed by creation of an end colostomy with closure of the rectal stump
- indicated in hemodynamically unstable patients (faster)
- those with ischemic/gangrenous bowel (risk of anastomosis leak)
Cecal Volvus Clinical Features
- Acute presentation: features of small bowel obstruction
- Insidious onset: recurrent episodes of right lower abdominal pain
Cecal Volvus Tx
- IV fluids; NPO; placement of a nasogastric tube
- Surgery
- Stable patients: ileocecal resection or right colectomy with ileocolic anastomosis
- Hemodynamically unstable patients
- Cecostomy
- Detorsion with cecopexy
Midgut Volvulus
torsion of a malrotated midgut causing mechanical bowel obstruction, mostly in neonates and infants
Midgut Volvulous Clinical Presentation
- Bilious vomiting with abdominal distension in a neonate/infant
- Signs of bowel ischemia: hematochezia
- older children/adults: recurrent episodes of abdominal pain and vomiting; failure to gain weight; malabsorption
MIdgut Volvulus Tx
- Initial resuscitation: NPO; nasogastric tube insertion; IV fluids
- broad-spectrum IV antibiotics
- Emergency surgery- Ladd Proceddure
Incidentally detected/asymptomatic intestinal malrotation: elective surgery
Volvulus Diagnostics
Abdominal x-ray (erect and supine)
- Sigmoid volvulus: coffee bean sign
- Cecal volvulus: kidney bean sign
- Bowel perforation: air under diaphragm
CT scan
- Whirl sign/ Whrilpool sign: pathognomonic for volvulus
Barium enema
- bird’s beak sign
Whril Sign
- characterized by a whorled appearance created by the twisting of one structure around another
- Twisted loops of bowel are seen on the axial plane of the CT scan.
- Twisted mesentry and vascular pedicle lies at the center of the whirl.
Megacolon
Loss of intestinal peristalsis and subsequent dilation of the colon in the abscence of a mechanical obstruction
- Acute megacolon
- Chronic megacolon
- Toxic megacolon
Acute Mega Colon
(Acute Colonic Pseudo-Obstruction/Olgivie’s Syndrome)
Acute dilation of the colon in the absence of a mechanical obstruction; characteristically seen in severely ill or postoperative patients
Acute Mega Colon
Etiology
- Occurs in seriously ill patients or those who have undergone a major surgical procedure
- Idiopathic; possible factors include:
- Electrolyte imbalance
- Drugs (anticholinergic drugs, opioid analgesics, antipsychotics, calcium channel blockers)
Acute Mega Colon
Pathophysiology
- Etiological factors →
- impairment/destruction of the autonomic nervous system →
- imbalance between sympathetic and parasympathetic control of intestinal motility
Acute Mega Colon
Clinical Features
- Gradual abdominal distention
- Abdominal pain
- Constipation/diarrhea
- Tympanitic abdominal percussion
- Decreased frequency of bowel sounds
- Signs of colonic ischemia or impending perforation: Fever, tachycardia, and peritoneal signs
Acute Megacolon
Treatment
Conservative management
- IV fluids and bowel rest (NPO)
- Bowel decompression
- Nasogastric tube
- Rectal tube
- Pharmacologic management: NeostigmineIndications
- No improvement > 24–48 hours
Surgery
- Signs of impending or actual colonic ischemia/perforation or peritonitis
- Failure of conservative therapy
Acute Megacolon
Diagnostics
- Abdominal x-ray: dilation of the cecum and right colon (occasionally up to the rectum) with/without multiple air-fluid levels; haustrae are preserved
- Contrast enhanced CT scan (oral and IV contrast)
- Confirms x-ray findings
Chronic Megacolon
Chronic colonic pseudo-obstruction
Permanent dilation of the colon caused by congenital/acquired colonic dysmotility in the absence of a mechanical obstruction
Chronic Megacolon
Etiology
- Congenital
- Hirschsprung disease
- Acquired
- Neuropathies (diabetic)
- Myopathies (Duchenne’s muscular dystrophy)
- Chronic Chagas disease
Chronic Megacolon
Clinical Features
Recurrent episodes of:
- Constipation
- Abdominal pain and distention
- Anorexia, early satiety, and nausea
Examination findings:
- Abdominal distention; mild abdominal tenderness
Chronic Megacolon
Diagnostics
- Abdominal x-ray: dilation of the cecum and right colon (occasionally up to the rectum) with/without multiple air-fluid levels; haustrae are preserved
- The cecum, ascending, and transverse colonare the first to dilate, followed by the splenic flexure, descending, and sigmoid colon.
Chronic Megacolon
Tx
Conservative management
- Dietary modifications
- Osmotic laxatives and enemas
- Prokinetic drugs
Surgery:
- patients who do not improve/worsen on conservative therapy
- colectomy with ileorectal anastomosis
- partia colectomy high chance of recurrance
Toxic Megacolon
A life-threatening, acute dilation of the colon associated with systemic toxicity
Toxic Megacolon
Etiology
Infectious colitis
- Bacterial: C. difficile (pseudomembranous colitis), Salmonella, Shigella, Campylobacterinfections
Inflammatory colitis:
- Ulcerative colitis, Crohn’s disease
Toxic Megacolon
Clinical Features
- (Bloody) diarrhea and vomiting
- Abdominal distention and pain
- Signs of sepsis (fever, tachycardia, hypotension) and dehydration
Toxic Megacolon
Diagnostics
Labs:
- neutrophilic leukocytosis, anemia, ↑ ESR/CRP, hypokalemia
Abdominal x-ray findings
- Dilation of the colon (transverse colon diameter > 6 cm)
- Loss of haustration
- Multiple air-fluid levels
Toxic Megacolon
Treatment
Conservative treatment
- Admission to intensive care unit
- Complete bowel rest: NPO
- Nasogastric tube insertion
- IV fluids
- Correction of fluid and electrolyte imbalances
Surgery
- No response to medical management within 24–72 hours; development of complications
- Subtotal colectomy and end ileostomy
- anastamosis contraindicated due to inflamed and friable bowel wall
Colonic Polyps
Abnormal colonic mucosal overgrowths.
- Pendunculated
- Sessile
Colonic Polyps
Epidemiology
∼ 30% of individuals > 50 years
Male> female
∼ 70% are adenomatous polyps
Colonic Polyp
Highest Malignancy Potential
Adenomatous polyps. Villous adenoma Histology: finger-like projections lined by dysplastic epithelium. Risk of malignancy: ∼ 50%. Frequency: 5–15%
Colonic Polyps
Clinical Features
Mostly asymptomatic
If symptomatic
- Blood in stool (hematochezia) is the most common symptom
- Change in bowel habits (constipation/diarrhea)
- Mucus in stool
Hereditary Polyposis Syndrome
- Adenomatous Polyposis Syndromes (Familial Adenomatous Polyposis)
- Hamartomatous Polyposis Syndromes
Familial Adenomatous Polyposis
Inheritance
- Mutation of the tumor suppressor gene APC (adenomatous polyposis coli)
- Autosomal dominant;
- positive family history
Familial Adenomatous Polyposis
Epidemiology
Develops during 3rd dacade of life
FAP
Clinical Features
- initially asymptomatic until progressing to colon cancer
- Altered bowel habits (constipation/diarrhea), blood in stool, and abdominal pain
- Congenital hypertrophy of the retinal pigment epithelium
FAP
Diagnosis
Colonoscopy: >100 polyps
gentic testing: APC mutations
FAP
Treatment
- Screening beginning at 10 years of age
- Prophylactic proctocolectomy + ileoanal anastomosis; diagnosis
- Screening upper endoscopy beginning at 25 years of age
- Celecoxib; sulindac
Gardner Syndrome
- FAP + extracolonic bony and/or soft tissue tumors (e.g., osteomas, desmoid tumors, sebaceous cysts, lipomas, fibromas)
Turcot Syndrome
Adenomatous colonic polyps + brain tumors
Hamartomatous Polyposis Syndromes
- Peutz-Jeghers Syndrome
- Juvenile Polyposis Syndrome
- Cowden Syndrome
- Cronkhite- Canada Syndrome
Peutz-Jeghers Syndrome
- 95% of patients have mucocutaneous hyperpigmentation
- Autosomal Dominant
- Enteroscopy: hamartomatous polyps throughout the gastrointerstinal tract
-
Prognosis
- The lifetime risk of colorectal cancer is ∼40%.
- Increased risk of ovarian, breast, and pancreatic cancer
Juvenile Polyposis Syndrome
Etiology: autosomal dominant with incomplete penetrance
Clinical features: Onset is within the first decade of life, often with gastrointestinal bleedingand anemia
Cronkhite- Canada Syndrome
- Etiology: probably immune-mediated (rare, nonfamilial disorder)
- Clinical features: GI polyposis with alopecia and cutaneous hyperpigmentation
Colorectal Rectal
