Clubbing

By: Wendwesen Alemu C-1 , 22-01-08 E.C

Clubbing can be defined as the selective bullous enlargement of the distal segments of the fingers and toes due to proliferation of connective tissue, particularly on the dorsal surfaceThere is increased sponginess of the soft tissue at the nail bed. It is also called

HIPPOCRATIC FINGERS, DRUMSTICK FINGERS or WATCH GLASS NAILS

Degrees of clubbing:

Grade 1 – Fluctuation of the nail bed. Grade 2 – Obliteration of the Lovibond angle.Grade 3 – Parrot beak appearance or drum stick appearanceGrade 4 – Hypertrophic Osteo Arthropathy (HOA)

Why is there clubbing?

Causes:Clubbing is associated with diseases of the lung, heart, GIT, endocrine system and miscellaneous diseasessimple way of remembering few causes of clubbing are:

C – Congenital Cyanotic Heart Disease, Cystic fibrosis, Crohn’s disease, Cholangiolitic cirrhosis,

L – Lung abscess, Lipoid pneumonia,U – Ulcerative colitis,B – Bronchiectasis, Bronchogenic carcinoma,B – Biliary cirrhosis,I – Infective endocarditis, idiopathic pulmonary

fibrosisN – Neoplasms of lung, liver, esophagus, small &

large bowel.G – Grave’s disease (thyroid acropachy)

Theories on ClubbingNeurogenic theory

a vagotomy causes a symptomatic improvement in the HOA, thus allowing us to infer that a vagal stimulus(from a tumour site) via neural reflexes can lead to proliferation of connective tissue at the distal extremitiesThis theory was unable to explain why conditions like CCHD and aneurysms cause clubbing.

Humoral theory Normally the lung throws out all the soluble substances by inactivation But in case of lung problems, these substances reach the systemic circulation in the active state and they stimulate the changes seen in HOA (Prostaglandins, ferritin, bradykinin and growth hormone) However this theory suffered a setback because normal levels of thee metabolites were found in HOA cases

Role of platelets Normally megakaryocytes and large platelets get destroyed in the lungIn cases where these is a lung pathology or CCHD or right to left shunts, these platelets escape and reach distal extremities interact with the endothelial cells and release platelet derived growth factor (PDGF) post activation.

PDGF and other mediators then activate the fibroblasts and transforming growth factor β (TGF-β) which lead to collagen production and connective tissue laying down ultimately giving rise to clubbing and HOAThis theory is supported by the evidence that plasma levels of von Willebrand factor were elevated in HOA cases. Further platelet clumps were demonstrated in infected heart valves, walls of aneurysms and valve grafts

Hypoxia Hypoxia is suggested to be a stimulus for HOA Hypoxia leads to opening of deep arterio-venous shunts and fistulae which increase blood flow to the extremities and leads to hypertrophy

Assessment of clubbingClinical methods to assess clubbing is done by

The obliteration of Lovibond angle can be assessed clinically by looking tangentially to observe for the angle between the cuticle and the proximal nail. (Normal angle = 15o from the skin or 160-165o from the nail)

The nail bed fluctuation is elicited by stabilising the finger between the index finger of both the hands such that the nail can be balloted between the two fingers. Now, either by using the thumb at the distal margin of the nail or by using one index finger the nail is balloted to check for fluctuation

Schamroth’s sign:

Normally when the two fingers are held together with the nails facing each other, a diamond shaped space is seen at the level of the proximal nail fold. Obliteration of this space indicates clubbing and is called as Schamroth’s +

SourceGeneral Medicine Clubbing.htm