Understanding Acute Abdomen

• Acute abdomen is sudden, severe abdominal pain needing quick diagnosis and treatment.
• Conditions include peptic ulcer disease, gastroenteritis, diverticulitis, acute cholelithiasis, and acute cholangitis.
• Also includes ruptured ectopic pregnancy, ovarian torsion, pelvic inflammatory disease, acute urinary infection, and nephrolithiasis.
• Further conditions are acute pyelonephritis, acute coronary disease, acute mesenteric ischemia, and ruptured abdominal aortic aneurysm (AAA).
• Additional acute abdominal conditions include acute appendicitis, acute pancreatitis, gastrointestinal perforation, mechanical intestinal obstruction, and acute urinary retention.
• Diagnosis uses physical examination to assess the patient.
• Choose a main diagnosis and two differential diagnoses based on assessment.
• Select and justify appropriate lab and imaging studies to support the main diagnosis.
• Interpret study results to confirm diagnosis and guide treatment.

Peptic Ulcer Disease

• Painful sores or ulcers in the lining of the stomach or duodenum

Gastroenteritis

• An intestinal infection marked by diarrhea, cramps, nausea, vomiting, and fever

Diverticulitis

• An infection or inflammation of pouches that can form in intestines.

Acute Cholelithiasis

• Sudden inflammation of the gallbladder, typically caused by gallstones

Acute Cholangitis

• A severe infection of the bile duct

Ruptured Ectopic Pregnancy

• A fertilized egg implants outside the uterus, usually in a fallopian tube, and ruptures

Ovarian Torsion

• Twisting of an ovary and sometimes the fallopian tube, cutting off blood supply

Pelvic Inflammatory Disease

• An infection of the female reproductive organs

Acute Urinary Infection

• A sudden infection in any part of the urinary system

Nephrolithiasis

• The presence of kidney stones in the kidney

Acute Pyelonephritis

• A sudden and severe kidney infection

Acute Coronary Disease

• Characterized by a sudden reduction of blood flow to the heart

Acute Mesenteric Ischemia

• A condition where blood supply to the small intestine is suddenly blocked

Ruptured Abdominal Aortic Aneurysm (AAA)

• A bulge in the wall of the aorta within the abdomen ruptures

Acute Appendicitis

• Inflammation of the vermiform appendix, a small, finger-like pouch attached to the cecum
• Typically caused by obstruction of the appendiceal lumen
• Obstruction can be caused by a fecalith, lymphoid hyperplasia, or, rarely, tumors
• Presents with periumbilical pain that migrates to the right lower quadrant (McBurney's point)
• Other symptoms include anorexia, nausea, vomiting, and low-grade fever
• Physical examination findings include right lower quadrant tenderness, guarding, and rebound tenderness
• Rovsing's sign (pain in the right lower quadrant with palpation of the left lower quadrant) may be present
• Psoas sign (pain with right hip extension) and obturator sign (pain with internal rotation of the right hip) may also be present
• Diagnosis is primarily clinical, but imaging studies such as CT scans or ultrasound may be used, especially in atypical cases or in women of childbearing age
• Elevated white blood cell count is a common laboratory finding
• Treatment involves surgical removal of the appendix (appendectomy)
• Appendectomy can be performed via open surgery or laparoscopically
• In some cases of uncomplicated appendicitis, antibiotic therapy may be considered as an alternative to surgery
• Complications of untreated appendicitis include perforation, peritonitis, abscess formation, and sepsis

Acute Pancreatitis

• An inflammatory condition of the pancreas
• Most common causes are gallstones and alcohol abuse
• Other causes include hypertriglyceridemia, medications, infections, trauma, and structural abnormalities of the pancreas or biliary tract
• Presents with severe, persistent epigastric pain that may radiate to the back
• Nausea, vomiting, abdominal distension, and fever are also common symptoms
• On physical examination, patients may have epigastric tenderness, decreased bowel sounds, and signs of dehydration
• In severe cases, signs of shock (tachycardia, hypotension) may be present
• Cullen's sign (periumbilical ecchymosis) and Grey Turner's sign (flank ecchymosis) are rare signs of retroperitoneal hemorrhage
• Diagnosis is based on clinical presentation, elevated serum amylase and lipase levels, and imaging studies
• CT scan is the preferred imaging modality for evaluating the severity of pancreatitis and identifying complications
• Management involves supportive care, including intravenous fluids, pain control, and nutritional support
• Most patients with mild to moderate pancreatitis improve with conservative management
• Severe pancreatitis may require intensive care unit admission and interventions such as endoscopic retrograde cholangiopancreatography (ERCP) to remove gallstones or drain pancreatic pseudocysts
• Complications include pancreatic pseudocyst, pancreatic necrosis, infection, acute respiratory distress syndrome (ARDS), and multi-organ failure

Gastrointestinal Perforation

• A full-thickness defect in the wall of the gastrointestinal tract, allowing leakage of intestinal contents into the peritoneal cavity
• Common causes include peptic ulcer disease, diverticulitis, appendicitis, bowel obstruction, trauma, and iatrogenic injury (e.g., during endoscopy or surgery)
• Presents with sudden onset of severe abdominal pain
• Other symptoms include abdominal tenderness, rigidity, guarding, rebound tenderness, fever, tachycardia, and hypotension
• Free air under the diaphragm on abdominal X-ray is a classic finding
• CT scan is more sensitive for detecting perforation and identifying the site of leakage
• Management involves resuscitation with intravenous fluids and antibiotics, followed by surgical repair of the perforation
• The specific surgical approach depends on the location and cause of the perforation
• Complications include peritonitis, sepsis, abscess formation, and death

Mechanical Intestinal Obstruction

• A blockage of the flow of intestinal contents through the small or large bowel
• Common causes include adhesions (scar tissue from previous surgery), hernias, tumors, volvulus (twisting of the bowel), intussusception (telescoping of one segment of bowel into another), and inflammatory bowel disease
• Obstruction can be partial or complete, and can occur at any level of the small or large intestine
• Small bowel obstruction typically presents with colicky abdominal pain, distension, nausea, vomiting, and inability to pass flatus or stool
• Large bowel obstruction may present with similar symptoms, but vomiting may be less prominent
• Physical examination findings include abdominal distension, high-pitched bowel sounds, and tenderness to palpation
• In late stages, bowel sounds may be absent
• Abdominal X-rays show dilated loops of bowel with air-fluid levels
• CT scan can help identify the site and cause of the obstruction
• Management includes nasogastric decompression, intravenous fluids, and correction of electrolyte imbalances
• Complete obstructions or obstructions with signs of strangulation (compromised blood supply) typically require surgical intervention
• Complications include bowel ischemia, perforation, peritonitis, sepsis, and death

Acute Urinary Retention

• The sudden inability to pass urine
• Can be caused by mechanical obstruction of the urethra, neurologic dysfunction, medications, or prostatic enlargement
• In men, the most common cause is benign prostatic hyperplasia (BPH)
• Other causes include urethral stricture, bladder stones, prostate cancer, and medications with anticholinergic effects
• Presents with suprapubic pain, urgency, and inability to void
• Physical examination reveals a palpable, distended bladder
• Diagnosis is based on clinical presentation and confirmed by bladder catheterization
• Post-void residual urine volume can be measured to assess the degree of retention
• Management involves bladder catheterization to relieve the obstruction
• A Foley catheter may be placed for continuous drainage, or intermittent catheterization may be performed
• The underlying cause of the retention should be investigated and treated
• In men with BPH, alpha-blockers or 5-alpha-reductase inhibitors may be prescribed to improve urinary flow
• Surgical options such as transurethral resection of the prostate (TURP) may be considered for refractory cases
• Complications include bladder overdistension, hydronephrosis, urinary tract infection, and bladder damage