A 63-year-old man comes to the physician complaining of cough and nocturnal wheezing. The cough is mostly non-productive, but sometimes a small amount of yellow sputum is produced. Past medical history is significant for hospitalization for pneumonia 2 years ago and osteoarthritis of the knees. The patient has a good appetite but has lost 6.8 kg (15 lb) over the last 3 months. He has a 40-pack-year smoking history and drinks 2-3 cans of beer a day on the weekends. His mother has type 2 diabetes mellitus and his father died of a stroke at age 67. His blood pressure is 140/80 mm Hg and pulse is 80/min. Chest hyperinflation and scattered expiratory wheezes are present on auscultation. The patient expires through pursed lips. His fingers demonstrate prominent clubbing that was not present 6 months ago. Which of the following is the most likely explanation for this patient's digital clubbing?

Question

A 63-year-old man comes to the physician complaining of cough and nocturnal wheezing.  The cough is mostly non-productive, but sometimes a small amount of yellow sputum is produced.  Past medical history is significant for hospitalization for pneumonia 2 years ago and osteoarthritis of the knees.  The patient has a good appetite but has lost 6.8 kg (15 lb) over the last 3 months.  He has a 40-pack-year smoking history and drinks 2-3 cans of beer a day on the weekends.  His mother has type 2 diabetes mellitus and his father died of a stroke at age 67.  His blood pressure is 140/80 mm Hg and pulse is 80/min.  Chest hyperinflation and scattered expiratory wheezes are present on auscultation.  The patient expires through pursed lips.  His fingers demonstrate prominent clubbing that was not present 6 months ago.  Which of the following is the most likely explanation for this patient's digital clubbing?

Quizplus · Accepted Answer

11ec25c8_d4ba_2aca_bc81_2b6a683c2abb_MD0003_00 Digital clubbing describes bulbous enlargement and broadening of the fingertips due to connective tissue proliferation at the nail bed and distal phalanx. It is diagnosed when the angle between the nail fold and the nail plate is >180° (Lovibond angle). Clubbing can occur by itself or associated with hypertrophic osteoarthropathy, which presents with painful joint enlargement, periostosis of long bones, and synovial effusions. Clubbing may be hereditary, but is most often due to pulmonary or cardiovascular diseases. The most common causes of secondary clubbing are lung malignancies, cystic fibrosis, and right-to-left cardiac shunts. Digital clubbing Lovibond angle Pathophysiology involves megakaryocytes that skip the normal route of fragmentation within pulmonary circulation (due to circulatory disruption from tumors, chronic lung inflammation) to enter systemic circulation. Megakaryocytes become entrapped in the distal fingertips due to their large size and release platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). PDGF and VEGF have growth-promoting properties that increase connective tissue hypertrophy and capillary permeability and vascularity, ultimately leading to clubbing. (Choices A and C) Lung hyperinflation (emphysema) and airflow obstruction are characteristic of chronic obstructive pulmonary disease (COPD). COPD alone does not cause digital clubbing, and presence of clubbing in patients with COPD should prompt a search for occult malignancy. (Choice B) Hypoxemia can activate local vasodilation and result in increased blood flow to distal portions of the digits. However, the presence of hypoxemia alone in COPD (in the absence of malignancy) is not associated with clubbing. (Choice E) Pulmonary hypertension is often present in patients with underlying advanced pulmonary or cardiovascular disease. However, it is not implicated in the pathogenesis of digital clubbing. Educational objective: Lung malignancies, cystic fibrosis, and right-to-left cardiac shunts are the most common causes of secondary digital clubbing. Chronic obstructive pulmonary disease (with or without hypoxemia) does not cause digital clubbing, and the presence of clubbing should prompt a search for occult malignancy. Hypertrophic osteoarthropathy refers to digital clubbing along with painful joint enlargement, periostosis of long bones, and synovial effusions. References: Clubbing: an update on diagnosis, differential diagnosis, pathophysiology, and clinical relevance. (http://www.ncbi.nlm.nih.gov/pubmed/15928621) Digital clubbing. (http://www.ncbi.nlm.nih.gov/pubmed/23243350)

A 63-Year-Old Man Comes to the Physician Complaining of Cough