36.1 Abdomen I: Esophagus (Hiatal Hernia, GERD, Achalasia, Caustic Injury, Barrett, Boerhaave, Mallory-Weiss, Cancer), Stomach and Duodenum (Peptic Ulcer Complications, Upper GI Bleeding, Gastric Cancer, GIST), Small Bowel (Obstruction, Ileus, Tumors, Typhoid and TB), Retroperitoneum and Abdominal Wall

Why this area matters

The TOS asks you to:

• identify risk factors;
• relate history and examination to the diagnosis;
• choose tests;
• list treatment options and operations of choice;
• prepare the patient and plan postoperative care;
• predict the prognosis and complications.

Peptic ulcer complications, upper GI bleeding, gastric cancer, bowel obstruction, typhoid perforation and abdominal TB are common surgical problems in Philippine hospitals.

Esophagus

• Hiatal hernia:
  • type I (sliding, the most common): the GE junction moves into the chest and is linked to GERD, so management is medical;
  • types II to IV (paraesophageal): the stomach herniates beside the esophagus and risks volvulus, strangulation and bleeding, so it is repaired surgically.
• GERD:
  • PPIs first;
  • laparoscopic Nissen fundoplication for refractory symptoms, regurgitation, large hiatal hernias or intolerance of drugs, after manometry and pH studies.
• Achalasia:
  • loss of inhibitory neurons in the myenteric plexus;
  • progressive dysphagia to solids and liquids, regurgitation and weight loss;
  • "bird's beak" on barium swallow;
  • manometry shows absent peristalsis and incomplete relaxation of the LES;
  • endoscopy is done to exclude cancer (pseudoachalasia);
  • treatment is laparoscopic Heller myotomy with partial fundoplication, POEM or pneumatic dilation, with botulinum toxin for frail patients;
  • achalasia slightly raises the risk of squamous cancer.
• Diffuse esophageal spasm: chest pain and dysphagia with a "corkscrew" esophagus.
• Caustic injury:
  • alkali (lye) causes deep liquefactive necrosis, and acids cause coagulative necrosis;
  • do not induce vomiting, neutralize or pass blind tubes;
  • protect the airway;
  • do endoscopy within 24 hours to grade the injury (not between days 5 and 15, when the wall is weakest);
  • perforation needs surgery;
  • late complications are strictures (dilation or replacement) and a raised squamous cancer risk decades later.
• Barrett esophagus:
  • intestinal metaplasia (columnar epithelium with goblet cells) from chronic GERD;
  • endoscopic surveillance, with ablation or resection of dysplasia;
  • a precursor of adenocarcinoma.
• Mallory-Weiss tear: a mucosal laceration at the GE junction after retching, typically with alcohol. It causes hematemesis, usually stops spontaneously, and can be treated endoscopically.
• Boerhaave syndrome:
  • full-thickness rupture, usually of the left posterolateral distal esophagus, after forceful vomiting;
  • Mackler triad: vomiting, chest pain and subcutaneous emphysema;
  • pneumomediastinum (Hamman crunch), left pleural effusion and sepsis;
  • diagnose with water-soluble contrast esophagram or CT;
  • treat with NPO, broad-spectrum antibiotics and early surgical repair with drainage (best within 24 hours); mortality rises steeply with delay.
• Esophageal cancer:

• Presentation: progressive dysphagia (solids, then liquids) and weight loss.
• Workup: endoscopy and biopsy, then staging with CT, endoscopic ultrasound and PET.
• Treatment: neoadjuvant chemoradiation followed by esophagectomy for locally advanced resectable disease; stenting for palliation of dysphagia.
• Benign tumors: the leiomyoma is the most common; it is submucosal and is enucleated if symptomatic.

Stomach and duodenum

• Peptic ulcer disease: caused by H. pylori and NSAIDs, and rarely Zollinger-Ellison syndrome (gastrinoma). Medical therapy heals most ulcers; surgery is for complications.

• Upper GI bleeding:
  • assess with a Glasgow-Blatchford score;
  • resuscitate (restrictive transfusion);
  • give IV PPI;
  • do endoscopy within 24 hours. The Forrest classification of ulcer stigmata predicts rebleeding: active spurting, visible vessel and adherent clot are high risk.
  • Variceal bleeding is managed differently.
• Gastric adenocarcinoma:
  • risk factors: H. pylori, smoked and salted foods, smoking, pernicious anemia, previous gastrectomy, family history (CDH1);
  • types: intestinal (distal, older men) and diffuse (signet-ring cells, linitis plastica, younger patients);
  • signs of spread: Virchow node (left supraclavicular), Sister Mary Joseph nodule (umbilicus), Krukenberg tumor (ovary) and Blumer shelf (rectal shelf);
  • treatment: gastrectomy with D2 lymphadenectomy with perioperative chemotherapy.
• Gastrointestinal stromal tumor (GIST):
  • arises from interstitial cells of Cajal and is c-KIT (CD117) positive;
  • treated by resection and imatinib.
• Gastric MALT lymphoma often regresses after H. pylori eradication.

Small intestine

Bowel Obstruction: Small Bowel versus Large Bowel Pathology

Mechanical intestinal obstruction interrupts normal caudad luminal transit. Differentiating small bowel obstruction (SBO) from large bowel obstruction (LBO) is a core diagnostic skill.

Volvulus of the Colon: Sigmoid versus Cecal Volvulus

• Sigmoid Volvulus ($75\%$ of volvulus): Torsion of redundant sigmoid colon on its elongated mesentery. Prevalent in elderly, bedridden, institutionalized, neuropsychiatric patients with chronic constipation and chronic laxative abuse. Plain radiograph shows an inverted U-shaped dilated loop devoid of haustra pointing toward the Right Upper Quadrant, producing the pathognomonic "coffee-bean sign" or "bent inner tube sign". Management: Emergent rigid or flexible sigmoidoscopy with rectal tube decompression (successful detorsion in $> 80\%$). Elective resection during the same admission is indicated due to high recurrence rates ($> 50\%$). Emergent laparotomy and Hartmann's resection are mandatory if bowel gangrene, perforation, or failure of endoscopic decompression occurs.

• Cecal Volvulus ($25\%$ of volvulus): Torsion of the cecum and ascending colon due to congenital failure of right peritoneal fixation. Prevalent in younger active adults ($30-50\text{ years}$). Abdominal radiograph shows a dilated, kidney- or comma-shaped cecal loop displaced into the Left Upper Quadrant. Endoscopic decompression is rarely successful and carries high perforation risk. Management is emergent exploratory laparotomy and right hemicolectomy with primary ileocolic anastomosis.

• Paralytic ileus:

  • after surgery, or with electrolyte disorders (hypokalemia), opioids, sepsis or retroperitoneal bleeding;
  • diffuse dilation of both small bowel and colon without a transition point;
  • managed with supportive care, correcting electrolytes and minimizing opioids.

• Small bowel tumors:

  • carcinoid (neuroendocrine) tumors, often in the ileum, cause carcinoid syndrome (flushing, diarrhea, right heart valve disease) only after liver metastasis, with raised urinary 5-HIAA;
  • adenocarcinoma (duodenum);
  • lymphoma;
  • GIST.
  • They present with obstruction, intussusception in adults, bleeding or weight loss.

• Typhoid perforation:

  • usually in the third week of typhoid fever;
  • an antimesenteric perforation of the terminal ileum (Peyer patches);
  • sudden worsening pain, peritonitis and pneumoperitoneum;
  • treated with resuscitation, antibiotics (ceftriaxone with metronidazole) and early laparotomy with primary repair or segmental resection;
  • mortality is high with delayed surgery.

• Abdominal tuberculosis:

  • favors the ileocecal region;
  • forms: ulcerative, hypertrophic or ulcerohypertrophic disease, peritoneal TB (ascites with high protein and lymphocytes, raised ADA, "doughy" abdomen), and nodal TB;
  • causes strictures with subacute obstruction, masses, perforation and fistulas;
  • anti-TB treatment, with surgery (stricturoplasty or limited resection) for obstruction or perforation.

• Meckel diverticulum ("rule of 2s"):

  • about 2% of people, about 2 feet from the ileocecal valve, 2 inches long, with 2 types of ectopic tissue (gastric and pancreatic), and often symptomatic by age 2;
  • causes painless rectal bleeding in children (technetium-99m pertechnetate scan), obstruction, intussusception and diverticulitis.

• Acute mesenteric ischemia:

  • pain out of proportion to examination in a patient with atrial fibrillation or vascular disease;
  • raised lactate late;
  • CT angiography;
  • treated with heparin, revascularization and resection of dead bowel.

Retroperitoneum and abdominal wall

• Retroperitoneal hematoma after trauma:
  • zone 1 (central: aorta, IVC, pancreas, duodenum): explore;
  • zone 2 (flank: kidneys, colon): explore after penetrating trauma, and selectively after blunt trauma;
  • zone 3 (pelvic): do not explore in blunt trauma; use a pelvic binder and angioembolization.
• Retroperitoneal tumors: most are malignant, mainly liposarcoma and leiomyosarcoma. They grow large before causing symptoms, and complete en bloc resection is the main treatment.
• Retroperitoneal fibrosis encases the ureters, causing obstruction. It can be idiopathic or IgG4-related, or caused by drugs or aneurysm.
• Abdominal wall:
  • incisional hernias follow wound infection, obesity and poor closure, and are repaired with mesh;
  • umbilical hernias in adults are repaired, because they can incarcerate;
  • diastasis recti is not a true hernia;
  • rectus sheath hematoma occurs with anticoagulation;
  • desmoid tumors are locally aggressive.
• Fascial dehiscence ("burst abdomen"):
  • usually around postoperative days 5 to 8;
  • often heralded by salmon-colored (serosanguinous) discharge;
  • cover the bowel with moist sterile dressings and return to the operating room;
  • risks are infection, malnutrition, steroids, obesity, coughing and poor technique.