Digital Clubbing: Tests, Pathogenesis, Grades, Causes and Differential DiagnosisAugust 26, 2012 | 9:38 pm | Medicine | One Comment
Clubbing is defined as the bulbous enlargement of the terminal phalanges due to proliferation of connective tissue between the fingernail and the bone. It is characterized by increase in anteroposterior as well as transverse diameter of nails and obliteration of onychodermal or lovibond’s angle (angle between the nail base and the adjacent skin fold).
Other names for Clubbing:
b. Hippocratic fingers
c. Lovibond’s sign
PATHOGENESIS OF CLUBBING
There is increase in pulp tissue due to proliferation of subungual connective tissue, interstitial edema and dilation of arterioles and capillaries.
DETECTING THE PRESENCE OF CLUBBING
1. Observe Lovibond’s angle: Bring the patient’s fingertip at the level of your eye and look tangentially for the onychodermal or lovibond’s angle (> or = 180 degrees in clubbing).
2. Fluctuation test: The patients fingertip is placed on the pulp of examiner’s two thumbs and held in this position by gentle pressure with the tips of examiner’s middle fingers applied on the patient’s proximal interphalangeal joint. The patient’s finger is then palpated over the base of the nail by the tips of examiner’s index fingers. There is increased fluctuation of the nail bed in clubbing due to softening of the nail-bed.
3. Schamroth’s window test: The sign is elicited by placing the dorsal surfaces of terminal phalanges on opposing fingers together. The normally formed diamond shaped window is obliterated in the presence of clubbing.
4. Digital index: Ratio of circumference of finger at nail-bed (NB) to distal interphalangeal joint (DIP) i.e. NB:DIP is calculated for all the 10 fingers and summed up. The final value is divided by 10 and the resulting value is digital index (>1 in clubbing).
5. Phalangeal depth ratio: Ratio of distal phalangeal depth (DPD) to interphalangeal joint depth (IPD) i.e. DPD:IPD of index finger measured using calipers (should touch the skin but not compress it) if >1 indicates clubbing.
Other conditions to look for while examining nails
- Pachyonychia (Thick nails): Pachyonychia congenita
- Onycholysis (Separation of nail from bed): Psoriasis, Tetracycline
- Destruction of nails: Severe lichen planus, Epidemolysis bullosa
- Missing nails: Inherited nail-patella syndrome
- Splinter hemorrhages: Trauma, Psoriasis, Rheumatoid arthritis, Bacterial endocarditis, Trichinosis
- Koilonychia (Brittle spoon-shaped nails): Iron Deficiency Anemia
- Half & Half nail (White proximal half and red or brown distal half of nails): Chronic renal failure
- Leukonychia (Whitening of nail plates): Hypoalbuminemia eg. Liver cirrhosis
- Nail-fold telangiectasia or erythema: Dermatomyositis, Systemic sclerosis, SLE
- Thinning and longitudinal ridging of nail plate: Raynaud’s phenomenon
- Curved, yellow nails: Bronchiectasis
GRADES OF CLUBBING
- I: Softening of the nail-beds and fluctuation
- II: I + Obliteration of onychodermal angle
- III: II + Increased anteroposterior and transverse diameter
- IV: III + Increased in pulp tissue (drumstick or parrot-beak)
- V: IV + Wrist and ankle swelling due to Hypertrophic osteoarthropathy
Hypertrophic Osteoarthropathy (HOA)
- Triad of digital clubbing, proliferative periostitis of long bones and arthritis
- Commonly seen in bronchiogenic carcinoma, mesothelioma, bronchiectasis and cirrhosis
- Typically seen as a long metaphyseal and diaphyseal smooth periosteal reaction involving the long bones
CAUSES OF CLUBBING
A) Bilateral Clubbing
- Cardiovascular: Cyanotic congenital heart disease (Fallot’s tetralogy), Subacute Bacterial Endocarditis (SABE), Atrial myxoma, Eisenmenger’s syndrome
- Lung and pleural: Bronchiectasis, Lung abscess, Bronchiogenic carcinoma, Empyema thoracis, Chronic interstitial lung disease, Pleural mesothelioma, Pulmonary arteriovenous fistula, Cystic fibrosis
- Liver: Portal cirrhosis, Amoebic liver abscess, Hepatocellular failure
- Ulcerative colitis
- Biliary cirrhosis
- Intestinal: Malabsorption, Crohn’s disease, Polyposis coli, Celiac disease
- Normal: Idiopathic
- Genetic: Pachydermoperiostitis (a syndrome that combines hyper-trophic osteoarthropathy and acromegalic features)
- Other: Thyrotoxicosis (Thyroid acropathy), Occupational (Jackhammer operators)
Note: Clubbing is not found in pure emphysema but may be found in chronic bronchitis. The presence of clubbing in a patient with COPD should prompt a search for an underlying (lung) cancer.
B) Unilateral Clubbing
Asymmetrical clubbing usually indicates impaired regional blood flow caused by localized vascular disease.
- Presubclavian coarctation of aorta (left sided clubbing)
- Pancoast tumor
- Aneurysm of subclavian artery
- Erythromelalgia (a rare neurovascular peripheral pain disorder commonly associated with myeloproliferative disorders in which blood vessels, usually in the lower extremities, are episodically blocked, then become hyperemic and inflamed)
- AV fistula of brachial vessels
Treatment for clubbing: There is no specific treatment for clubbing. The treatment is for the underlying primary condition.
ADDITIONAL AIDS FOR DIFFERENTIAL DIAGNOSIS OF CLUBBING
- Drumstick type clubbing:Bronchiectasis, Congenital cyanotic heart disease (Mnemonic: BCD)
- Parrot-beak type clubbing: Bronchiogenic carcinoma
- Painful clubbing: Bronchiogenic carcinoma, SABE, Lung abscess
- Reversible clubbing: Lung abscess, Empyema thoracis
- Unidigital clubbing: Hereditary, Repeated local trauma, Median nerve injury, Sarcoidosis
- Clubbing with cyanosis: Cyanotic heart disease, Pulmonary AV shunt, Pulmonary disease like lung abscess, bronchiectasis, cystic fibrosis
- Acute clubbing (Clubbing within 2 weeks after onset of illness): Lung abscess, Empyema thoracis
- Recurrent clubbing: May occur in pregnancy in otherwise healthy females
Clubbing limited to upper or lower limbs alone is called differential clubbing.
- Clubbing limited to upper extremity: Chronic obstruction of veins of the upper extremity (i.v drug users)
- Clubbing limited to lower extremity: PDA With reversal of shunt (Eisenmenger PDA), Infected abdominal aortic aneurysm
a. Subungual tumor or cyst
b. Subperiosteal bone resorption :
- People working with vinyl choride (acrosteolysis)
- Bedside Clinics in Medicine Part I by Arup Kumar Kundu
- Hutchison’s Clinical Methods
- Digital Clubbing: A sign of underlying disease by Bernard Karnath, MD
- Clubbing: An update on diagnosis, differential diagnosis, pathophysiology, and clinical relevance by Kerith E. Spicknall, BA, Matthew J. Zirwas, MD, and Joseph C. English III, MD
Tags: clubbing, hypertrophic osteoarthropathy, schamroths sign
Last updated: September 2, 2012