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Abdominal Swelling and Ascites

Chapter 53 | Part 2: Cardinal Manifestations and Presentation of Diseases · Part 2 – Cardinal Manifestations & Presentation · Chapter 53

Key Clinical Points

  1. Abdominal swelling causes are categorized by the 'Six Fs': Flatus, Fat, Fluid, Fetus, Feces, and Fatal Growth.
  2. Ascites is graded by visibility: Grade 1 (ultrasound only), Grade 2 (physical exam), Grade 3 (marked distention).
  3. SAAG ≥ 1.1 g/dL indicates portal hypertension; SAAG < 1.1 g/dL indicates non-portal hypertensive causes.
  4. Spontaneous Bacterial Peritonitis (SBP) is defined by an ascitic fluid polymorphonuclear neutrophil (PMN) count ≥ 250/μL.
  5. Diuretic therapy for ascites typically uses a spironolactone to furosemide ratio of 40:100 (e.g., 400 mg to 160 mg).
  6. Paracentesis is safe even in coagulopathy; complications are infrequent.
  7. Chylous ascites is characterized by milky fluid with triglyceride levels >200 mg/dL.
  8. Secondary peritonitis is suggested by ascitic fluid with multiple pathogens and low glucose.
  9. Tuberculous peritonitis typically shows lymphocytosis and ADA >30–45 U/L.
  10. Refractory ascites is defined by persistence despite sodium restriction and maximum diuretics, or by diuretic intolerance.

DEFINITION & CLASSIFICATION

• Abdominal Swelling: Manifestation of various diseases; patients may report bloating or increased girth. • Clinical Presentation: Pain is less frequent than discomfort; when present, often suggests infection, peritonitis, or pancreatitis. • Associated Symptoms: Distention from ascites may cause new-onset inguinal/umbilical hernias or dyspnea due to diaphragmatic pressure. • The Six Fs (Causes of Swelling): 1. Flatus 2. Fat 3. Fluid 4. Fetus 5. Feces 6. Fatal Growth (e.g., neoplasm) • Ascites Definition: Accumulation of fluid in the abdominal cavity. • Grading of Ascites: 1. Grade 1: Detectable only by ultrasonography. 2. Grade 2: Detectable by physical examination. 3. Grade 3: Results in marked abdominal distention.

EPIDEMIOLOGY

• Global Context: In developing countries, infections are the leading cause of liver involvement and jaundice (e.g., malaria, babesiosis, leptospirosis, M. tuberculosis, hepatitis A–E, various viral hemorrhagic fevers). • Clinical Indicators: Fever or abdominal pain suggests concurrent infection, sepsis, or gallstones. • Acute Liver Failure: Development of encephalopathy and coagulopathy in a jaundiced patient without prior liver disease requires urgent transplant evaluation. • AIDS Cholangiopathy: Incidence has dropped significantly since the 1990s due to potent antiretrovirals.

ETIOLOGY & PATHOPHYYSICOLOGY

• Cirrhotic Ascites Mechanism: Result of portal hypertension and renal salt/water retention. • Portal Hypertension Pathophysiology: 1. Increased hepatic resistance due to fibrosis (disrupted architecture) → impaired blood flow. 2. Activation of hepatic stellate cells → smooth-muscle contraction and fibrogenesis. 3. Decreased intrahepatic eNOS → decreased nitric oxide → increased intrahepatic vasoconstriction. • Systemic Response: 1. Increased systemic nitric oxide, VEGF, and TNF → splanchnic arterial vasodilation. 2. Splanchnic blood pooling → perceived hypovolemia by kidneys. 3. Activation of ADH, sympathetic nervous system, and RAAS → renal sodium and water retention. • Non-Cirrhotic Ascites Mechanisms: 1. Peritoneal carcinomatosis (tumor cells produce protein-rich fluid; fluid drawn from extracellular space). 2. Tuberculous peritonitis (tubercles on peritoneum exude proteinaceous fluid). 3. Pancreatic ascites (leakage of pancreatic enzymes). 4. Hypoalbumminemia (nephrotic syndrome, protein-losing enteropathy, or malnutrition). • Prevalence: 1. Cirrhosis: 84% of cases. 2. Cardiac, Peritoneal carcinomatosis, and 'Mixed': 10–15% of cases. 3. Other (Massive metastasis, infection, pancreatitis, renal disease): Less common.

CLINICAL FEATURES

• History: 1. Timing/onset of bloating and distention. 2. Relationship to food or bowel movements. 3. Prior surgery, dietary habits, medications. 4. Malignancy signs: weight loss, night sweats, anorexia. 5. Obstruction signs: inability to pass stool/flatus, nausea, vomiting. 6. Risk factors for liver disease (alcohol use) and heart failure or TB. • Physical Examination: 1. Systemic Signs: Lymphadenopathy (Virchow's node → malignancy); JVP elevation; Kussmaul's sign; pericardial knock; tricuspid regurgitation murmur. 2. Liver/Spleen signs: Spider angiomas, palmar erythema, caput medusae, gynecomastia. 3. Abdominal Exam: • Inspection: Uneven distention or mass. • Auscultation: Absence of bowel sounds (obstruction/ileus); high-pitched localized sounds; umbilical venous hum (portal hypertension). • Percussion: Tympanic (gas) vs. Dull (mass/fluid). Note: ≥ 1500 mL fluid required for detection by physical exam. • Palpation: Tenderness, mass, splenomegaly, nodular liver; palpation of liver may show pulsations in right-sided heart failure.

DIFFERENTIAL DIAGNOSIS

• General Causes (The Six Fs): Flatus, Fat, Fluid, Fetus, Feces, Fatal Growth. • Ascites Specific Etiologies: 1. Cirrhosis (84%). 2. Cardiac ascites. 3. Peritoneal carcinomatosis. 4. Mixed ascites. 5. Massive hepatic metastasis. 6. Infection (Tuberculosis, Chlamydia). 7. Pancreatitis. 8. Renal disease (Nephrotic syndrome).

DIAGNOSTIC APPROACH

  1. Imaging Studies: • X-ray: Detect dilated loops (obstruction/ileus). • Ultrasound: Detect ≥ 100 mL fluid, hepatosplenomegaly, nodular liver, or mass. • CT: Used if malignancy or pancreatic disease is suspected; detects advanced cirrhosis and portal hypertension.
  2. Laboratory Evaluation: • Liver function (biochemistry), serum albumin, PT/INR. • CBC (check for cytopenias from portal HTN or leukocytosis/anemia from infection). • Amylase/Lipase (pancreatitis). • Urinalysis (nephrotic syndrome).
  3. Paracentesis: • Procedure: Safe even in coagulopathy; preferred site is LLQ (deeper fluid, thinner wall). • Analysis: Gross appearance, albumin/protein levels, cell count/differential, Gram stain, culture (in blood culture bottles).
  4. SAAG Calculation & Interpretation: • Formula: Serum Albumin - Ascitic Albumin = SAAG. • SAAG ≥ 1.1 g/dL → Portal Hypertension (Cirrhosis, Heart failure, Budd-Chiari, SNS, Massive metastasis). • SAAG < 1.1 g/dL → Non-portal hypertensive causes (Tuberculosis, Peritoneal carcinomatosis, Nephrotic syndrome, Pancreatitis, IVC obstruction).
  5. Ascitic Protein Differentiation: • Protein ≥ 2.5 g/dL + SAAG ≥ 1.1 → Heart failure, early Budd-Chiari, SNS. • Protein < 2.5 g/dL + SAAG ≥ 1.1 → Cirrhosis, late Budd-Chiari, massive liver metastases.
  6. Specialized Tests: • Adenosine Deaminase (ADA): >30–45 U/L (sensitivity >90% for TB). • Culture: Sensitivity 35–50% for TB. • Gold Standard: Laparotomy or laparoscopy with peritoneal biopsies.

MANAGEMENT & TREATMENT

  1. Initial Management: • Sodium restriction: 2 g/d. • Fluid restriction: If serum sodium <125 mEq/L.
  2. Pharmacologic Therapy (Diuretics): • Combination: Spironolactone and Furosemide. • Spironolactone: Aldosterone antagonist; max dose 400 mg/day. • Furosemide: Loop diuretic; max dose 160 mg/day. • Ratio: 40:100 (Spironolactone to Furosemide). • Substitution: Amiloride (5–40 mg/d) if gynecomastia is distressing.
  3. SBP Treatment: • First-line: Cefotaxime, 2 g every 12 hours for 5 days. • Monitoring: Repeat paracentesis after 48 hours; confirm PMN count decreased by ≥ 25%.
  4. Non-Pharmacologic Management: • Large-Volume Paracentesis (LVP): Use IV albumin (6–8 g/L of fluid removed) to reduce risk of postparacentesis circulatory dysfunction.
  5. Advanced Interventions: • TIPS: Superior to LVP for reducing reaccumulation; increases risk of hepatic encephalopathy. • Alfapump: For refractory ascites (high frequency of technical difficulties/renal dysfunction).
  6. Specific Conditions: • Tuberculous peritonitis → Standard antituberculosis therapy. • Malignant ascites → Serial LVPs, transcutaneous drainage, or rarely peritoneovenous shunt/Alfapump.

COMPLICATIONS & PROGNOSIS

• Spontaneous Bacterial Peritonitis (SBP): 1. Definition: Ascitic fluid PMN count ≥ 250/μL. 2. Clinical Presentation: Increased girth, fever, nausea, vomiting; abdominal tenderness in only 40% of cases. 3. Pathogens: Gram-negative rods (E. coli, Klebsiella), streptococci, enterococci. 4. Diagnostic Clues: • Multiple pathogens + high PMN → Secondary peritonitis (ruptured viscus/abscess). • Multiple pathogens + low PMN → Bowel perforation from paracentesis needle. 5. Prevention: Paracentesis within 12 hours of admission reduces mortality. • Refractory Ascites: 1. Diuretic resistant: Persistence despite sodium restriction and max diuretics. 2. Diuretic intractable: Development of side effects (e.g., hyperkalemia) preventing max doses.

SPECIAL POPULATIONS

• Pregnancy: 1. Increased abdominal girth typically noted at 12–14 weeks gestation. 2. Transition of uterus from pelvis to abdomen causes noticeable expansion.

KEY PEARLS & HIGH-YIELD POINTS

• SAAG Rule: ≥ 1.1 g/dL is the threshold for portal hypertension. • Diuretic Ratio: Remember the 40:100 ratio (Spironolactone:Furosemide). • SBP Threshold: PMN count ≥ 250/μL defines SBP. • Tuberculosis: High ADA (>30–45 U/L) is highly sensitive for tuberculous ascites in non-cirrhotic patients. • Chylous Ascites: Look for milky fluid and triglycerides >200 mg/dL.

FLOWCHARTS

SAAG Algorithm for Diagnosis of Ascites

  1. Assess Ascitic Protein Level:
  2. If Ascitic protein < 2.5 g/dL:
  3. Indicates high probability of portal hypertension.
  4. Potential Diagnoses: Cirrhosis, Late Budd-Chiari syndrome, Massive liver metastases.
  5. If Ascitic protein ≥ 2.5 g/dL:
  6. Branch A (Portal Hypertension related):
  7. Includes: Heart failure / constrictive pericarditis, Early Budd-Chiari syndrome, IVC obstruction, Sinusoidal obstruction syndrome.
  8. Branch B (Non-portal hypertension related):
  9. Includes: Biliary leak, Nephrotic syndrome, Pancreatitis, Peritoneal carcinomatosis, Tuberculosis.