II. Causes: Cardiovascular Disorders
- Bacterial Endocarditis
- Cyanotic Congenital Heart Disease
- Cardiac tumors
- Aortic aneurysm
- Infected aortic graft
- Secondary Polycythemia
III. Causes: Pulmonary Disorders
- Lung tumors (primary or metastases, esp. in comorbid COPD)
- Pleural tumors (particularly Mesothelioma)
- Mediastinal tumors
- Lung Abscess or empyema
- Bronchiectasis (rare cause)
- Pulmonary Tuberculosis
- Sarcoidosis
- Bronchogenic cyst
- Cystic Fibrosis
-
Chronic Obstructive Pulmonary Disease (Emphysema)
- Not typically associated with Clubbing, but when present associated with a four fold increase in Lung Cancer risk
IV. Causes: Gastrointestinal Disorders
- Neoplasms of liver, Esophagus, or bowel
- Inflammatory Bowel Disease (e.g. Ulcerative Colitis)
- Hepatic Cirrhosis
- Chronic Obstructive Jaundice or biliary Cirrhosis
- Amebiasis
- Intestinal Tuberculosis
- Subphrenic or Liver Abscess
- Celiac Sprue (Gluten Sensitive Enteropathy)
V. Causes: Miscellaneous Disorders
- Myxedema or Thyrotoxicosis
- Hematologic malignancies
- Polyarteritis Nodosa
- Idiopathic (Primary or familial)