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GENERAL SURGERY
Dr. S. Gallinger
Gordon Buduhan and Sam Minor, editors
Dana McKay, associate editor
PREOPERATIVE PREPARATION............. 2
SURGICAL COMPLICATIONS................. 2
Wound Complications Urinary and Renal Respiratory Cardiac Paralytic Ileus Post-Operative Delirium Post-Operative Fever Intra-abdominal Abscess ACUTE ABDOMEN........................... 6 Specific “Signs” on Physical Examination Evaluation ESOPHAGUS................................ 9 Hiatus Hernia Structural Lesions Motility Disorders Other Disorders Esophageal Perforation Esophageal Carcinoma STOMACH AND DUODENUM................ 12 Gastric Ulcers Duodenal Ulcers Gastric Carcinoma Complications of Gastric Surgery BOWEL OBSTRUCTION...................... 15 Small Bowel Obstruction Large Bowel Obstruction SMALL INTESTINE.......................... 18 Tumours of Small Intestine Meckel’s Diverticulum APPENDIX................................. 19 Appendicitis Tumours of the Appendix INFLAMMATORY BOWEL DISEASE........... 20 Crohn’s Disease Ulcerative Colitis LARGE INTESTINE......................... 21 Diverticular Disease Angiodysplasia Volvulus Colorectal Polyps Colorectal Carcinoma Ileostomies and Colostomies ANORECTUM............................... 26 Hemorrhoids Anal Fissures Anorectal Abscess Perirectal Suppuration Fistula-in-ano Pilonidal Disease Rectal Prolapse Anal Neoplasms HERNIA.................................... 28
MCCQE 2000 Review Notes and Lecture Series General Surgery 1
LIVER.................................. 30
Liver Cysts Liver Abscesses Neoplasms Portal Hypertension Liver Transplantation BILIARY TRACT......................... 34 Cholelithiasis Biliary Colic Acute Cholecystitis Complications of Cholecystectomy Acalculous Cholecystitis Gallstone Pancreatitis Gallstone Ileus Diagnostic Evaluation of Biliary Tree Choledocholithiasis Acute Cholangitis Carcinoma of the Bile Duct Jaundice
PANCREAS............................. 39 Acute Pancreatitis Chronic Pancreatitis Pancreatic Cancer SPLEEN................................ 41 Hypersplenism Splenectomy FISTULA................................ 42 BREAST................................ 42 Fibrocystic Disease Fibroadenoma Fat Necrosis Papilloma Differential Diagnosis of Nipple Discharge Mastitis Breast Cancer Male Breast Lumps THYROID............................... 47 VASCULAR - ARTERIAL DISEASES....... 47 Arterial Insufficiency Chronic Ischemia Critical Ischemia Acute Limb Ischemia Abdominal Aortic Aneurysm Ruptured Abdominal Aortic Aneurysm Aortic Dissection VASCULAR - VENOUS DISEASES......... 51 Deep Vein Thrombosis Varicose Veins Superficial Thrombophlebitis Chronic Deep Vein Insufficiency HIV AND GENERAL SURGERY........... 54 Susceptible Organs in GI Tract Unusual Malignancies Indications for Surgery in HIV Positive Patients Nosocomial Transmission CANCER GENETICS...................... 56
General Surgery 2 MCCQE 2000 Review Notes and Lecture Series
PREOPERATIVE PREPARATION Notes
o consent
o consults - anesthesia, medicine, cardiology, etc...
o components - blood components: group and screen or
crossmatch depending on procedure
o diet - NPO after midnight
o AAT, vital signs routine
o IV - balanced crystalloid at maintenance rate (4:2:1 rule)
- Ringer's lactate or normal saline
o investigations
- CBC, U/A, lytes, BUN, creatinine
- INR/PT, PTT with history of bleeding disorder
- ABGs if predisposed to respiratory insufficiency
- CXR (PA and lateral) unless < 35 years old or previously abnormal within past 6 months
- ECG > 35 years old or as indicated by past cardiac history
o drugs (including oxygen)
- patient's regular meds including prednisone - consider pre-op boost
- prophylactic antibiotics (e.g. cefazolin) if
- clean/contaminated cases (i.e. GI/GU/respiratory tracts are entered)
- contaminated cases - trauma
- insertion of foreign material (e.g. vascular grafts)
- high risk patients (e.g. prosthetic heart valves, rheumatic heart disease)
- bowel prep (decreases bacterial population e.g. Ancef, Cipro, Flagyl)
o drains
- nasogastric tube
- indications: gastric decompression, analysis of gastric contents, irrigation/dilution of gastric contents, feeding (only if necessary ––> due to risk of aspiration, naso-jejunal tube preferable)
- contraindications: absolute - obstruction of nasal passages due to trauma, suspected basilar skull fracture, relative - maxillofacial fractures; for these may use oral-gastric tube
- Foley catheter
- indications: to accurately monitor urine output, decompression of bladder, relieve obstruction
- contraindications: suspected disruption of the urethra, difficult insertion of catheter
SURGICAL COMPLICATIONS
WOUND COMPLICATIONS
Wound Infection
o wounds become infected in the OR while open
o risk of infection depends on type of procedure
- clean (excisional biopsy) - 3%
- clean-contaminated (GI, biliary) - 5-15%
- contaminated (surgery on unprepped bowel, emergency surgery for GI bleeds/perforation) - 15-40%
- dirty (penetrating trauma) - 40%
o most common etiologic agent = S. aureus
o bowel operations - consider enteric organisms
o predisposing factors
- patient characteristics: age, diabetes, steroids, immunosuppression, malnutrition, patient with other infections, traumatic wound, radiation
- other factors: prolonged preoperative hospitalization, duration of surgery, break in sterile technique, use of drains, multiple antibiotics
o clinical presentation
- typically fever POD 3-
- pain, wound erythema, induration, frank pus or purulosanguinous discharge
o treatment
- re-open affected part of incision, culture wound, pack, heal by secondary intention
General Surgery 4 MCCQE 2000 Review Notes and Lecture Series
SURGICAL COMPLICATIONS... CONT. Notes
o treatment
- immediate removal of debris and fluid from airway
- consider endotracheal intubation and flexible bronchoscopic aspiration
- IV antibiotics to cover oral aerobes and anaerobes
Pulmonary Edema
o occurs during or immediately after operation
o results from circulatory overload
- overzealous volume replacement
- left ventricular failure
- shift of fluid from peripheral to pulmonary vascular bed
- negative airway pressure
- alveolar injury due to toxins
o treatment
• O
- remove obstructing fluid
- correct circulatory overload
- diuretics, PEEP in intubated patient
Respiratory Failure
o clinical manifestations - dyspnea, cyanosis, evidence of
obstructive lung disease, pulmonary edema, unexplained decrease in PaO
o earliest manifestations - tachypnea and hypoxemia
- NB: hypoxemia may initially present with confusion/delerium
o treatment
- O2 by mask
- pulmonary toilet
- bronchodilators
- treatment of acute respiratory insufficiency - mechanical ventilation
o if these measures fail to keep PaO2 > 60, consider ARDS
o control of post-operative pain can decrease pulmonary complications
- problematic with thoracic and upper abdominal operations
CARDIAC COMPLICATIONS
o abnormal ECGs common in post-operative period
o compare with pre-op ECG
o common arrhythmia - SVT
Myocardial Infarction
o surgery increases risk of MI
o majority of cases on operative day or within first 3 postoperative days
o incidence
- 0.5% in previously asymptomatic men > 50 years old
- 40-fold increase in men > 50 years old with previous MI
o risk factors
- pre-operative hypertension
- pre-operative CHF
- operations > 3 hours
- intra-operative hypotension
- angina pectoris
- MI in 6 months preceding surgery
PARALYTIC ILEUS
o normal bowel sounds disappear following abdominal surgery
o also follows peritonitis, abdominal trauma, and immobilization
o return of GI motility following abdominal surgery varies
- small bowel motility returns by 24-48 hours
- gastric motility returns by 48 hours
- colonic motility - up to 3-5 days
o due to paralysis of myenteric plexus
o two forms
- intestinal ileus
- gastric dilatation
o symptoms
- abdominal distension and vomiting
- absent or tinkly bowel sounds
MCCQE 2000 Review Notes and Lecture Series General Surgery 5
SURGICAL COMPLICATIONS... CONT. Notes
o treatment
- NG tube and fluid resuscitation
- for prolonged ileus, consider TPN
POST-OPERATIVE DELIRIUM
o disturbance of sleep-wake cycle
o disturbance of attention
o fluctuating course throughout day
o incidence: 40% (likely an underestimate)
o under-recognized (28% missed)
o no correlation with type of anesthetic agent
o risk factors
50 years old
- pre-existing cognitive dysfunction
- depression
- peri-operative biochemical derangements
5 prescribed medications post-operatively
- use of anticholinergic medications preoperatively
- cardiopulmonary bypass
- ICU setting
POST-OPERATIVE FEVER
o fever does not necessarily imply infection
o timing of fever may help identify cause
o "6W's" - CLINCAL PEARL
- Wind (pulmonary)
- Water (urine-UTI)
- Wound
- Walk (DVT-PE)
- Wonder drugs (drug fever)
- Wanes (rhymes with veins: IV sites)
o 0-48 hours
- usually atelectasis
- consider early wound infection (especially Clostridia , Group A Strep)
- leakage of bowel anastomosis (tachycardia, hypotension, oliguria, abdominal pain)
- aspiration pneumonia
o POD ≥ 3
- after day 3 infections more likely
- UTI- patient instrumented? e.g. foley
- wound infection (usually POD 3-5)
- IV site - especially IVs in place > 3 days
- septic thrombophlebitis
- intra-abdominal abscess (usually POD 5-10)
- DVT (POD 7-10)
o also consider - cholecystitis, PE, sinusitis, prostatitis,
peri-rectal abscess, drug fever, URTI, factitious fever
INTRA-ABDOMINAL ABSCESS
o localized intra-abdominal infection
o a collection of pus walled-off from rest of peritoneal cavity by
inflammatory adhesions and viscera
o number of bacteria exceed host's ability to terminate infection
o danger: may perforate secondarily —> diffuse bacterial peritonitis
o usually polymicrobial
o clinical manifestations
- persistent, spiking fever, dull pain, weight loss, leukocytosis
- impaired function of adjacent organs e.g. ileus or diarrhea (with rectal abscess)
- co-existing effusion e.g. pleural effusion with subphrenic abscess
o diagnosis
- usually by U/S or CT
- don't forget to perform DRE (boggy mass in pelvis)
o treatment
- drainage is essential
- antibiotics to cover aerobes and anaerobes
Notes
MCCQE 2000 Review Notes and Lecture Series General Surgery 7
ACUTE ABDOMEN... CONT.
Physical Exam and Work-Up
o steps in physical exam
- general observation: patient position (i.e. lying still vs. writhing)
- vitals: postural changes, fever
- status of hydration
- cardiovascular/respiratory examination
- abdominal examination observation: distention, scars, visible peristalsis auscultation: absent, decreased, normal, increased bowel sounds percussion: hypertympanic sounds in bowel obstruction, percussion tenderness indicative of peritonitis palpation: tenderness, abdominal masses
- CVA tenderness
- specific signs
- hernias, male genitalia
- rectal/pelvic exam
o labs
- CBC and differential
- electrolytes, BUN, creatinine
- amylase levels
- liver function tests
- urinalysis
- stool for occult blood
- others as indicated
- ECG, ß-hCG, ABG, septic workup, lactate (ischemic bowel)
o radiology
- 3 views abdomen
- CXR
- others as indicated
- U/S, CT, endoscopy, IVP, peritoneal lavage, laparoscopy
o indications for urgent operation
- physical findings
- peritonitis
- severe or increasing localized tenderness
- progressive distension
- tender mass with fever or hypotension (abscess)
- septicemia and abdominal findings
- bleeding and abdominal findings
- suspected bowel ischemia (acidosis, fever, tachycardia)
- deterioration on conservative treatment
- radiologic
- free air
- massive bowel distention (colon > 12 cm)
- space occupying lesion with fever
- endoscopic
- perforation
- uncontrollable bleeding
- paracentesis
- blood, pus, bile, feces, urine
Approach to the Critically Ill Surgical Patient
ABC, I’M FINE ABC - see Emergency Medicine Notes I - IV: two large bore IV’s with normal saline, wide open M - Monitors: O2 sat, EKG, BP F - Foley catheter to measure urine output I - Investigations: see above N - +/– NG tube E - Ex rays
Notes
General Surgery 8 MCCQE 2000 Review Notes and Lecture Series
ACUTE ABDOMEN... CONT.
Figure 1. Abdominal Incisions Drawing by Jackie Robers
Layers of the Abdominal Wall
o skin
o superficial fascia
- Camper's fascia ––> dartos muscle
- Scarpa's fascia ––> Colles' fascia
o muscle
- external oblique ––> inguinal ligament, external spermatic fascia, fascia lata
- internal oblique ––> cremasteric muscle
- transversalis abdominus ––> posterior inguinal wall
o transversalis fascia ––> internal spermatic fascia
o peritoneum ––> tunica vaginalis
o at midline
- rectus abdominus muscle: in rectus sheath, divided by linea alba
- above semicircular line of Douglas (midway between symphysis pubis and umbilicus): - anterior rectus sheath = external oblique aponeurosis and anterior leaf of internal oblique aponeurosis posterior rectus sheath = posterior leaf of internal oblique aponeurosis and transversus
- below semicircular line of Douglas:
- anterior rectus sheath = aponeurosis of external, internal oblique, transversus
o arteries: superior epigastric (branch of internal thoracic), inferior
epigastric (branch of external iliac), both arteries anastomose and lie behind the rectus muscle
General Surgery 10 MCCQE 2000 Review Notes and Lecture Series
ESOPHAGUS... CONT. Notes
- 90% success rate
- indications for surgery
- complications of sliding hernia or gastroesophageal reflux (especially stricture, severe ulceration, fibrosis)
- symptoms refractory to conservative and medical treatment
- complete mechanical failure of lower esophageal sphincter (LES)
Paraesophageal Hiatus Hernia (Type II)
o gastroesophageal junction undisplaced and stomach fundus
herniates into chest (other bowel loops, spleen may also herniate with fundus)
o 10% of esophageal hernias
o clinical presentation
- asymptomatic
- heartburn/reflux uncommon
- pressure sensation in lower chest, dysphagia
o complications
- hemorrhage
- incarceration, obstruction, and strangulation
- palpitations rarely
o treatment
- surgery in almost every case to prevent severe complications
- procedure: reduce hernia, suture to posterior rectus sheath (gastropexy), close defect in hiatus
- excellent results
Mixed Hiatus Hernia (Type III)
o a combination of Types I and II
STRUCTURAL LESIONS (see Gastroenterology Notes)
MOTILITY DISORDERS (see Gastroenterology Notes)
OTHER DISORDERS
o esophageal varices (see Liver Section)
Mallory Weiss Tear (see Gastroenterology Notes)
ESOPHAGEAL PERFORATION
o etiology: esophagus at risk of rupture due to lack of serosa
- instrumental: endoscopy, dilation, biopsy, intubation, placement of NG tubes
- spontaneous (Boerhaave's syndrome) due to frequent and forceful vomiting, common in alcoholics and bulimics
- trauma
- corrosive injury
- carcinoma
o clinical presentation: neck, chest or upper abdominal pain,
dyspnea, subcutaneous emphysema, pneumothorax, fever
o differential diagnosis: MI, dissecting aortic aneurysm, pulmonary embolus
o diagnosis
- CXR shows pneumothorax, pneumomediastinum, pleural effusion, subdiaphragmatic air
- swallowing study with water soluble contrast (hypaque)
o treatment: NPO, fluid resuscitation, IV antibiotics, early surgical repair
(less than 24 hours to prevent infection and subsequent repair failure)
ESOPHAGEAL CARCINOMA
o epidemiology
- 1% of all malignant lesions
Notes
MCCQE 2000 Review Notes and Lecture Series General Surgery 11
ESOPHAGUS... CONT.
- male:female = 3:
- 50-60 years of age
- increased incidence in Blacks, especially squamous cell carcinoma
o risk factors
- physical agents: alcohol, tobacco, nitrosamines, lye, radiation
- structural: diverticula, hiatus hernia, achalasia
- Barrett's epithelium (8-10% risk of adenocarcinoma, monitor every 1-2 years by endoscopy and biopsy)
- chronic iron deficiency (Plummer-Vinson syndrome)
o pathology
- upper 20-33%, middle 33%, lower 33-50%
- squamous cell carcinoma: 80-85% (mid-esophagus)
- adenocarcinoma: 5-10% but incidence rising in U.S.
- up to 40-50% (lower esophagus) - associated with Barrett's esophagus
o clinical presentation
- frequently asymptomatic - late presentation
- often dysphagia, first for solids then liquids
- weight loss, weakness
- regurgitation and aspiration (aspiration pneumonia)
- hematemesis, anemia
- odynophagia then constant pain
- tracheoesophageal, bronchoesophageal fistula
- vocal cord paralysis
- spread directly or via blood and lymphatics - trachea (coughing), recurrent laryngeal nerves (hoarseness), aorta, liver, lung, bone, celiac and mediastinal nodes
o diagnosis and investigations
- barium swallow first - narrowing site of lesion (shelf or annular lesion)
- esophagoscopy - biopsy for tissue diagnosis and extent of tumour
- bronchoscopy - for upper and mid esophageal lesions due to high incidence of spread to tracheobronchial tree
- CT scan: for staging - adrenal, liver, lung, bone metastases
o treatment
- surgery
- lower third
- thoracic esophagectomy, pyloroplasty (or pyloromyotomy) and celiac lymph node resection
- reconstruction of GI continuity with either stomach or colon
- middle or upper third
- esophagectomy extends to cervical esophagus
- anastomosis performed through separate neck incision
- check margins by frozen section during surgery
- contraindications: invasion of tracheobronchial tree or great vessels, lesion > 10 cm
- radiation
- if unresectable, palliation (relief of dysphagia in 2/3 of patients, usually transient)
- chemotherapy
- alone, or pre and post-operatively
- multimodal - combined chemotherapy, radiation and surgery
- palliative or cure, survival rates higher than surgery alone
- palliative treatment
- resection, bypass, dilation and stent placement, laser ablation
- prognosis
- 5-8% operative death rate
- 12% five-year survival (Stage I) post surgery
- prognosis slightly better if squamous cell carcinoma
MCCQE 2000 Review Notes and Lecture Series General Surgery 13
STOMACH AND DUODENUM... CONT. Notes
Figure 3. Billroth I and II Gastrectomies
Drawings by Jackie Robers
GASTRIC CARCINOMA Latif, A. Gastric Cancer Update on Diagnosis, Staging and Therapy. Postraduate Medicine. 1997:102(4):231-6.
o epidemiology
- male:female = 2:
- most common age group 50-59 years
- decreased by 2/3 in past 50 years
o risk factors
- smoking
- alcohol
- smoked food, nitrosamines
- H. pylori causing chronic atrophic gastritis
- pernicious anemia associated with achlorhydria and chronic atrophic gastritis
- gastric adenomatous polyps
- previous partial gastrectomy (> 10 years post-gastrectomy)
- hypertrophic gastropathy
- hereditary nonpolyposis colon cancer
o pathology
- histology
- 92% adenocarcinoma (8% lymphoma, leiomyosarcoma)
- morphology - Borrman classification
- polypoid (25%)
- ulcerative (25%)
- superficial spreading (15%)
- linitis plastica (10%) - diffusely infiltrating
- advanced/diffuse (35%) - tumour has outgrown above 4 categories
o clinical presentation
- suspect when ulcer fails to heal or is on greater curvature of stomach and cardia
- usually late onset of symptoms
- insidious onset of: postprandial abdominal fullness, weight loss, anorexia, vague abdominal pain, dysphagia, hematemesis, epigastric mass (25%), hepatomegaly, fecal occult blood, iron-deficiency anemia, melena
- rarely: Virchow's node (left supraclavicular node), Blumer's shelf (palpable mass in pouch of Douglas in pelvis), Krukenberg tumour (mets to ovary), Sister Mary Joseph nodule (umbilical nodule), malignant ascites
- spread: liver, lung, brain
o diagnosis
- EGD and biopsy, upper GI series with air contrast (poor sensitivity if previous gastric surgery)
- CT for distant metastases
o staging (see Table 2)
General Surgery 14 MCCQE 2000 Review Notes and Lecture Series
STOMACH AND DUODENUM... CONT. Notes
Table 2. Staging of Gastric Carcinoma
Stage Criteria Prognosis (5 year survival)
I mucosa and submucosa 70% II extension to muscularis propria 30% III extension to regional nodes 10% IV distant metastases or involvement 0% of continuous structures overall 10%
TNM CLASSIFICATION
Primary Tumour (T)
o T1 limited to mucosa and submucosa
o T2 extends into, but not through, serosa
o T3 through serosa, does not invade other structures
o T4 through serosa and invades contiguous structures
Nodal Involvement (N)
o N0 no lymph nodes involved
o N1 involvement of nodes within 3 cm of the primary tumour
o N2 involvement of nodes more than 3 cm from primary tumour
which are removable at operation, including those along left gastric, splenic, celiac and common hepatic arteries
o N3 involvement of intra-abdominal lymph nodes not removable at
operation including para-aortic, hepatoduodenal, retropancreatic, and mesenteric
Distant Metastasis (M)
o M0 no known distant metastasis
o M1 distant metastasis present
Table 3. American Joint Committee on Cancer’s Stage Grouping of Gastric Cancer
Stage TNM Classification
0 T1S N0 M IA T1 N0 M IB T1 N1 M T2 N0 M II T1 N2 M T2 N1 M T3 N0 M IIIA T2 N2 M T3 N1 M T4 N0 M IIIB T3 N2 M T4 N1 M IV T4 N2 M Any T Any N M
o treatment: surgery for adenocarcinoma
- proximal lesions
- total gastrectomy and esophagojejunostomy (Roux-en-Y)
- include lymph node drainage to clear celiac axis (may require splenectomy)
- distal lesions
- distal radical gastrectomy (wide margins, en bloc removal of omentum and lymph node drainage)
- palliation
- gastric resection to decrease bleeding and to relieve obstruction thus enabling the patient to eat
- overall 5 year survival - 10%
- lymphoma
- chemotherapy ± surgery ± radiation
General Surgery 16 MCCQE 2000 Review Notes and Lecture Series
BOWEL OBSTRUCTION... CONT. Notes
- strangulating - surgical emergency
- impaired blood supply, leads to necrosis
- early shock
- fever + increased WBC count
- cramping pain turns to continuous ache
- vomiting gross or occult blood
- abdominal tenderness or rigidity
o radiological (see Colour Atlas C1)
- CXR, abdominal x-ray (3 views)
- dilated edematous loops of small bowel (ladder pattern - plica circularae)
- air-fluid levels
- colon often devoid of gas unless only partial obstruction
o laboratory
- normal early
- hemoconcentration
- leukocytosis (marked in strangulation)
- increased amylase
- metabolic alkalosis —> proximal SBO
- metabolic acidosis —> bowel infarction
o treatment
- NG tube to relieve vomiting and abdominal distention
- stabilize vitals, fluid and electrolyte resuscitation
- if partial SBO (i.e. if passage of stool, flatus) ––> conservative management
- if complete SBO (obstipation) ––> surgery (cannot rule out strangulation)
- trial of medical management may be indicated in Crohn's, recurrent small bowel obstruction, carcinomatosis
o prognosis
- mortality: non-strangulating 2%, strangulating 8% (25% if > 36 hours)
o complications
- open perforation
- septicemia
- hypovolemia
Table 4. Small Bowel Obstruction vs. Paralytic Ileus
Small bowel obstruction Paralytic ileus nausea and vomiting + + abdominal distention + + obstipation + + abdominal pain crampy minimal or absent bowel sounds normal, increased absent, decreased AXR ladder pattern, air fluid levels, gas present throughout no gas in colon small and large colon
LARGE BOWEL OBSTRUCTION
o etiology
- colon carcinoma 60%
- diverticulitis 20%
- volvulus 5%
o other causes of large bowel obstruction
• IBD
- benign tumours
- fecal impaction/foreign body
- adhesions
- hernia (especially sliding type)
- intussusception (children)
- endometriosis
MCCQE 2000 Review Notes and Lecture Series General Surgery 17
BOWEL OBSTRUCTION... CONT. Notes
o clinical presentation
- slower in onset, less pain, later onset of vomiting, less fluid/ electrolyte disturbance than small bowel obstruction
- crampy abdominal pain in hypogastrium
- continuous, severe abdominal pain in ischemia, peritonitis
- distension, constipation, obstipation, anorexia
- nausea and late feculent vomiting
- high-pitched (borborygmi) or absent bowel sounds
- may have visible peristaltic waves
- open loop (safe):10-20%
- incompetant ileocecal valve allows relief of colonic pressure as contents reflux into ileum
- closed loop (dangerous): 80-90%
- ileocecal valve competent, allowing build up of colonic pressures to dangerous level
- compromise of lymphatic, venous and arterial circulation —> infarction
- cecum at greatest risk of perforation due to Laplace’s Law (Pressure = wall tension/radius)
- high risk of perforation if cecum diameter
12 cm on AXR - suspect impending perforation in the presence of tenderness over the cecum - if obstruction at ileocecal valve ––> symptoms of SBO
o diagnosis
- x-ray: "picture frame" appearance
- hypaque enema
- do not use contrast - may become inspissated and convert partial to complete LBO
o treatment
- goal: decompression to prevent perforation
- correct fluid and electrolyte imbalance
- surgical correction of obstruction (usually requires temporary colostomy)
- volvulus: sigmoidoscopic decompression or barium enema followed by operative reduction if unsuccessful
o prognosis
- dependent upon age, general medical condition, vascular impairment of bowel, perforation, promptness of surgical management
o mortality
- overall: 20%
- cecal perforation: 40%
o Ogilvie's syndrome: pseudo-obstruction, distention of colon
without mechanical obstruction
- associations: long term debilitation, chronic disease, immobility, narcotic use, polypharmacy, recent orthopedic surgery, post-partum
- diagnosis: cecal dilatation on AXR, if diameter > 12 cm, largely increased risk of perforation
- treatment: decompression with enema, if unsuccessful, decompression with colonoscope, nasogastric tube, rectal tube; if perforation or ischemia, surgery
MCCQE 2000 Review Notes and Lecture Series General Surgery 19
SMALL INTESTINE... CONT. Notes
o lymphoma
- proximal jejunum in patients with celiac disease
- usually distal ileum
- clinically: perforation followed by obstruction or bleeding
- presents as fever, malabsorption, abdominal pain
- treatment
- low grade: chemotherapy with cyclophosphamide
- high grade: surgical resection, radiation
- palliative: somatostatin, doxorubicin
- prognosis: 65-80% overall; 95% if localized
- survival: 40% at 5 years
MECKEL'S DIVERTICULUM
o persistent vitelline duct remnant on antimesenteric border of ileum;
can contain small intestinal, gastric, colonic, pancreatic mucosa
o most common diverticulum of GI tract
o rule of 2's: 2% of the population; symptomatic in 2% of cases;
found within 2 feet (10-90 cm) of the ileocecal valve
o clinical presentation: bleeding, obstruction, inflammation
(mimic appendicitis), intussusception, perforation
- painless bleeding due to peptic ulceration of heterotropic gastric mucosa (50% of patients < 2 years old)
o investigations
- technetium Tc99 can localize bleeding ectopic gastric mucosa
o treatment: fluid and electrolyte restoration, surgical resection if symptomatic
APPENDIX
APPENDICITIS
o epidemiology
- 6% of population
- 80% between 5-35 years of age
- atypical presentation in very young and very old
o pathogenesis
- luminal obstruction of appendix
- children to young adult: hyperplasia of submucosal lymphoid follicles
- adult: fecolith
- more rarely: tumour, stricture, foreign body
- obstruction —> bacterial overgrowth ––> inflammation/swelling —> ischemia—> gangrene/perforation
o clinical presentation
- only reliable feature is progression of signs and symptoms
- low grade fever
- vague mid abdominal discomfort or crampy pain
- anorexia, nausea and vomiting after pain starts
- migration of pain to RLQ (localized)
- tenderness at McBurney's point, RLQ on rectal exam
- positive Rovsing's sign, rebound tenderness, psoas sign, obturator sign
o diagnosis
- mild leukocytosis with left shift unless perforation
- x-rays: usually nonspecific; free air if perforated, look for calculus
- consider CT scan
- consider pelvic U/S or laparoscopy in female
o treatment
- surgical (possible laparoscopy)
- the decision to operate is acceptable even if only 70-80% are found to have true appendicitis
- need to be aggressive, especially in young females since perforation may cause infertility due to tubal damage
- morbidity/mortality 0.6% (uncomplicated), 5% if perforated
o complications
- perforation
- 25-30%
- more common at extremes of age
- increase in fever and pain
General Surgery 20 MCCQE 2000 Review Notes and Lecture Series
APPENDIX... CONT. Notes
- peritonitis: local (if walled-off by omentum) or generalized
- appendiceal abscess (phlegmon)
- presents as appendicitis plus RLQ mass
- diagnosis by U/S or CT
- interval appendectomy (6 weeks) as needed after optimal preparation (aspiration, antibiotics)
TUMOURS OF THE APPENDIX (rare)
o benign
- most common type
- usually an incidental finding
o malignant
- carcinoid tumours
- appendix is the most common location
- may produce carcinoid syndrome with liver metastases
- treatment: appendectomy if < 2 cm and not extending into serosa; right hemicolectomy if
2 cm or obvious nodal involvement or base of appendix involved
- adenocarcinoma
- 50% present as acute appendicitis
- spreads rapidly to lymph nodes, ovaries, and peritoneal surfaces
- treatment: right hemicolectomy
- malignant mucinous cystadenocarcinoma
- usually present as abdominal distension and pain
- treatment: appendectomy
- prognosis: local recurrence is inevitable, mortality 50% at 5 years
INFLAMMATORY BOWEL DISEASE
CROHN'S DISEASE (see Gastroenterology Notes) (see Colour Atlas C4)
Surgical Management
o intervention required in 70-75% of patients when complications arise
o goal of surgery is to conserve bowel - resect as little as possible
o indications
- SBO due to stricture and inflammation ~ indication in 50% of surgical cases
- fistula: enterocolic, vesicular, vaginal, cutaneous abscess
- less common indications —> perforation, hemorrhage, intractable disease (toxic megacolon), failure to thrive (especially children), perianal disease
o procedures
- palliative, not curative
- ileocecal resection with incidental appendectomy (unless base of appendix involved)
- strictureplasty - widens lumen in chronically scarred bowel
- exclusion bypass - bypass unresectable inflammatory mass, but later risk of cancer in excluded segment
o complications
- short gut syndrome (diarrhea, steatorrhea, malnutrition)
- fistulas
- biliary stones (due to decreased bile salt absorption leading to increased cholesterol precipitation)
- kidney stones (due to loss of Ca++ in diarrhea leading to increased oxalate absorption and hyperoxaluria ––> stones)
o prognosis
- recurrence rate at 10 years: ileocolic (50%), small bowel (50%), colonic (40-50%)
- 80-85% of patients who need surgery lead normal lives
- mortality 15% at 30 years
- re-operation at 5 years: primary resection 20%, bypass 50%
