Thoracic Abnormalities Associated With Acute/Chronic Liver Disease

Jud W. Gurney, MD, FACR

DIFFERENTIAL DIAGNOSIS

Common

Varices
Alpha-1 Antiprotease Deficiency
Hepatic Hydrothorax
Noncardiac Pulmonary Edema

Less Common

Hepatopulmonary Syndrome
Portopulmonary Hypertension
Cystic Fibrosis
Hepatocellular Carcinoma Metastases
Sarcoidosis

Rare but Important

Lymphocytic Interstitial Pneumonia
Amiodarone Pulmonary Toxicity
Heterotaxy Syndrome

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Elevated right hemidiaphragm may be secondary to underlying liver disease

Helpful Clues for Common Diagnoses

Varices
- Most common complication of portal hypertension
- Radiographic clues: Small liver, splenomegaly, lower paraspinal widening
- CT: Serpiginous vessels surrounding thickened distal esophageal wall
  - Vessels may be unopacified on arterial phase imaging
- Rarely, portal veins may decompress into pulmonary veins across pleural adhesions or inferior pulmonary ligament leading to right-to-left shunt
  - Splenopneumopexy: Obsolete surgical procedure of left hemidiaphragm with abrasion of spleen and left lower lobe allowing collaterals to develop
Alpha-1 Antiprotease Deficiency
- Inherited (autosomal dominant) deficiency of alpha-1 antitrypsin (A1AT)
  - Hepatic A1AT expressed in liver, released into circulation
  - In deficiency, A1AT accumulates in liver leading to cirrhosis
  - 5-10% of patients > 50 years old with A1AT have cirrhosis
- CT: Panlobular emphysema, primarily in lower lung zones
  - Mild cylindrical bronchiectasis also common (40%)
- Pulmonary function preserved until 5-6th decade in nonsmokers (3rd decade in smokers)
- Emphysema major cause of death in smokers
- Liver disease major cause of death in nonsmokers
Hepatic Hydrothorax
- Definition: Pleural effusion in cirrhosis in absence of cardiopulmonary disease
- Prevalence in cirrhotic patients (5-10%)
- Right pleural effusion (85%), left (13%), bilateral (2%)
- May occur in absence of ascites
Noncardiac Pulmonary Edema
- Seen in up to 40% with fulminant hepatic failure
- High mortality rate

Helpful Clues for Less Common Diagnoses

Hepatopulmonary Syndrome
- Triad of chronic liver disease (usually cirrhosis), increased alveolar-arterial oxygen gradient on room air, intrapulmonary vascular dilatation
- May be related to liver’s inability to break down circulating vasodilators (thought to be nitric oxide)
- Prevalence 20% in those awaiting orthotopic liver transplantation
- CT: Dilated peripheral arteries (2x larger than adjacent bronchi), primarily in lower lobes
- V/Q scan: Macroaggregated albumin bypasses lungs and results in systemic activity in brain and kidneys
- Reversible after orthotopic liver transplantation
Portopulmonary Hypertension
- May be related to liver’s inability to break down circulating vasoconstrictive agents
- Not related to severity of liver disease
- Prevalence: 2-5% in patients with cirrhosis
- CT findings identical to other causes of pulmonary hypertension: Enlarged central pulmonary arteries, attenuation of peripheral pulmonary arteries, mosaic attenuation
- Mean survival 15 months
- Relative contraindication to orthotopic liver transplantation
Cystic Fibrosis
- Hereditary disorder (autosomal recessive) that affects chloride transport
- Airways primarily affected
  - Bronchiectasis usually predominant in upper lobes
- Up to 40% have focal biliary cirrhosis, 10% go on to develop biliary cirrhosis
Hepatocellular Carcinoma Metastases
- Typical manifestation is multiple variable-sized pulmonary nodules
- Proclivity of hepatocellular carcinoma to invade veins may give rise to intravascular metastases
Sarcoidosis
- Drug complication of interferon therapy in patients with hepatitis C infection
- Sarcoid primarily affects chest (75%) or skin
- Radiographic findings identical to typical sarcoidosis, ranging from symmetric hilar adenopathy to perilymphatic nodularity

Helpful Clues for Rare Diagnoses

Lymphocytic Interstitial Pneumonia
- Part of a spectrum of lymphoproliferative disorders
- Association between primary biliary cirrhosis and Sjögren syndrome
- CT: Ground-glass opacities (100%), poorly defined centrilobular nodules
  - Thin-walled cysts most distinctive finding (80%), involve < 10% of total lung, may be only finding
Amiodarone Pulmonary Toxicity
- Antiarrhythmic agent with 3 iodine molecules
- Toxicity is dose related and accumulates in liver and lung
  - Acute presentation: High-opacity areas of lung consolidation
  - Chronic presentation: Diffuse interstitial thickening
Heterotaxy Syndrome
- Situs describes position of cardiac atria and viscera
- Atrial situs best determined by location of liver
- Situs ambiguous or heterotaxy syndrome
  - Asplenia: Right-sided symmetry
  - Polysplenia: Left-sided symmetry
- If discordant location of stomach bubble and cardiac apex, then consider asplenia or polysplenia