Acute Abdomen: Basic Knowledge and Additional Information

I. Intestinal Obstruction

1. Small Bowel Obstruction

• Description: Fluid levels, air levels located in the mid-abdomen, wide-based, low-arched, extending from the right iliac fossa (RIF) to the left iliac fossa (LIF).

• Note:

• RIF: Right Iliac Fossa

• LIF: Left Iliac Fossa

• Fluid Level: Indicates a severe degree of bowel obstruction.

• Air Level: Indicates a mild degree of bowel obstruction.

• Wide base: A characteristic feature of the fluid level in small bowel obstruction.

2. Large Bowel Obstruction

• Description: Fluid levels, air levels run around the abdomen, narrow-based, high-arched.

• Note:

• Narrow base: A characteristic feature of the fluid level in large bowel obstruction.

• High arched: Fluid levels in large bowel obstruction are usually higher arched compared to small bowel obstruction.

3. High Obstruction (Duodenal)

• Description: May not have fluid levels, air levels.

• Note:

• High obstructions are less common than small bowel and large bowel obstructions.

• Due to the high location of obstruction, fluid levels or air levels may not be clearly visible.

4. Late, Low Obstruction

• Description: Fluid levels, air levels throughout the abdomen.

• Note:

• Late obstruction usually occurs after bowel obstruction has persisted for a while.

• Fluid levels and air levels are distributed throughout the abdomen.

II. Appendicitis

1. Appendiceal SA (Sonography) 3-layer Structure (from outer to inner)

• Appendiceal lumen (1cm): Hyperechoic

• Mucosa, submucosa (<1cm): Hypoechoic

• Serosa and muscle layer (1-1.5cm): Hyperechoic

2. SA Image of Acute Appendicitis

• Appendix size >6cm. There are 3 types:

• Tubular

• Sausage-shaped

• Bead-like

• Appendiceal wall > 1.5cm

• Structural changes

3. Change in Appendiceal Sound Structure from inside out

• Hypoechoic: Inflammatory tissue + mucosa, submucosa

• Hyperechoic: Appendiceal wall (serosa and muscle)

• Hypoechoic: Surrounding inflammatory fluid

4. Note:

• Inflammatory fluid surrounds the appendiceal wall, which is a characteristic feature of acute appendicitis.

• Appendicitis should be differentiated from other pathologies such as mesenteric adenitis, diverticulitis, etc.

III. Intussusception

1. Causes of Intussusception in Children

• Increased bowel motility

• Irritable bowel

• Hirschsprung’s disease

• Chronic diarrhea

2. Causes of Intussusception in Adults

• Tumor

• Scarring due to bowel adhesions

• Post-surgery (PS)

3. Predisposing Factors for Intussusception

• Mesenteric adenitis

• Infants: Increased bowel motility due to the ileocecal valve

• Lymph node inflammation

• Two opposing waves

• Winter (may be related to respiratory viruses)

4. SA Image of Intussusception Mass

• Transverse view: Target-like pattern. Hyperechoic center, hypoechoic periphery (>3cm)

• Longitudinal view: Sandwich-like: The intussusceptum invaginates deeply into the intussuscipiens.

IV. Acute Pancreatitis

1. Causes of Acute Pancreatitis

• Gallstones

• Alcoholism, obesity

• Hyperlipidemia (HLP): Hyperlipidemia, hypercalcemia, diabetes

• Trauma (T) due to accidents or interventions

• Drug or toxin poisoning

2. Edematous Pancreatitis

• SA: Localized hypoechoic or isoechoic

• CT: Decreased attenuation

• Change in pancreatic border. Fat infiltration around the pancreas

• Diagnosis (D) is difficult if there is no fluid around the pancreas

3. Necrotizing Pancreatitis

• Enlarged pancreas, inhomogeneous structure. Fluid around the pancreas/abdomen/left pleura

4. Complications of Acute Pancreatitis

• Pancreatic pseudocyst

• Bowel obstruction

• Gastrointestinal bleeding (due to pancreatic fluid destroying the gastrointestinal tract or increased portal pressure)

• Peritonitis (P), chronic pancreatitis, pancreatic abscess

V. Liver Rupture

1. Grade 1 Liver Rupture

• SA: See rupture line, or area of contusion with hyperechoic, inhomogeneous appearance

• CT: Decreased attenuation, irregular, possible hematoma around

• Differentiate (D) from fissures or blood vessels

2. Grade 2 Liver Rupture

• Intracapsular rupture: When the capsule is not ruptured

• See contusion with localized hematoma within the capsule

• If bleeding continues, it will lead to Grade 2

3. Grade 3 Liver Rupture

• Primary (1st stage): Rupture associated with capsular tear of the liver, spleen causing bleeding outside

• Secondary (2nd stage): Stage 1 blood contained within the capsule, stage 2: increased pressure causing capsular rupture, blood spills into the abdomen —> sign (S) of acute blood loss

4. Grade 4 Liver Rupture: Pedicle Avulsion

• More common in the spleen than the liver

• Image of blood around the liver, spleen, and abdominal hemobilia

5. Grade 5 Liver Rupture

• Pedicle avulsion combined with parenchymal injury

Note:

• Grades of liver rupture are classified based on the degree of injury and bleeding.

• Prompt management of liver rupture is required to avoid mortality.

VI. Additional Information

• CT VRTC: Computed tomography scan

• SA: Ultrasound

• RT: Appendix

• HLP: Hyperlipidemia

• AL: Amylase

• VK: Bacteria

Additionally, please note:

• The above information is for reference only and cannot replace the opinion of a doctor.

• If you experience any abnormal symptoms, please consult a doctor immediately for diagnosis and treatment.