Nail Clubbing.

Happy November! Hope you are all functioning well despite last night's sugar high. I saw lots of cute kiddos in their costumes last night. Such a fun holiday.




In my Physical and Clinical Diagnosis (PCD) class (basically my physical exam class) we keep learning how no matter what physical complaint the patient has, that the skin, hair, and nails of the patient most definitely should be examined. It is unbelievable how many unassociated conditions can affect these areas of the body. For instance, nail clubbing is a phenomenon in which the fingers on the nails start to swell and balloon out. It almost looks as if marbles have been inserted in the ends of the fingers as they start to appear round and swollen. Clubbing is painless and will subside once the underlying condition is treated. Now what is odd is that nail clubbing is usually a side effect of a LUNG or HEART condition. Crazy how a chest condition shows up in the most distal part of our upper extremities! Unfortunately the reason WHY these conditions are associated with nail clubbing is still unknown... sometimes the body works in mighty mysterious ways.

However, there are four main theories behind the etiology of clubbing: including the production excess vasodilators, tissue hypoxia (i.e. lack of oxygen in the finger tissue), a neurocirculatory reflex, or due to some abdnormal genetic factors.

Here is how I'm making sense of the condition: when the lung and heart are distressed and thus lower in oxygen (hypoxia), they secrete vascular endothelial growth factors. These growth factors then act on the distal ends of the fingers, causing excess growth and swelling. Another hypothesis is that the capillaries in the nail are altered by the lung and heart condition. These vessels may lead to edema of the connective tissue in the nails, causing the enlargement.



To diagnose nail clubbing, an easy test can be preformed: place your two index finger nails on to of each other, such that the two fingers face each other and the nails touch. In between the two nails, there should be a teeny-tiny diamond-shaped space. If this "diamond" of space is present, then the nails are of normal shape and no clubbing is present.

Image sources here.