###### Created: 2022-09-15 14:52 ###### Areas & Topics: #medicine #pathology ###### Note Type: #permanent ###### Connected to: [[Paediatric History & Examination]] - Clubbing is where swelling of the terminal phalanx (end of the fingers) causes the angle between the nail and nail-bed to change or distort - 1% of all adults admitted to hospital have clubbing, and 40% of those adults will have a serious underlying disease. - The most common cause of clubbing is lung cancer. ### Aetiology - There are several causes of acquired nail clubbing which include infectious, neoplastic, inflammatory, and vascular diseases. - Clubbing can be idiopathic or hereditary as well. ### Pathophysiology - The main finding in areas with clubbing seems to be increased capillary density. - This is thought to be caused by peripheral megakaryocytes releasing mainly platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), alongside other signalling proteins. - These factors and proteins cause increased vascularity and permeability, which overall lead to changes in the connective tissue. - This could suggest that any condition which causes shunting of blood past the lungs or the liver, reducing the metabolism of angiogenic factors, may be involved in causing clubbing, but this is uncertain. ![[18127.jpg]] ![[Dedos_con_acropaquia.jpg]] ### Schamroth's Window - This is a clinical sign used to assess whether a patient has clubbing. - You assess it by getting the patient to put the dorsal side of their fingers together. - In normal patients, you should be able to see a small diamond-shaped gap or window whereas this will not be present in cases of clubbing. ![[Schamroth’s-window-1067800247.png]] ### Resources https://www.ncbi.nlm.nih.gov/books/NBK539713/