Oedema is the accumulation of excessive fluid in the subcutaneous tissue. When oedema results from lymphatic stasis, the term lymphoedema is used. Oedema may be pitting or non-pitting. Subcutaneous oedema is referred to as pitting when, after pressure is applied to a small area, the indentation persists for some time after release of the pressure (Fig. 49). Pitting oedema is caused by either systemic diseases (generalised) or local conditions involving just the affected extremities. The most common systemic diseases involve the heart, liver and kidneys. In these diseases, oedema occurs primarily because of water retention or fluid leaking into the interstitial spaces. The most common local conditions that cause oedema involve venous obstruction, e.g. varicose veins, DVT. Non-pitting oedema is observed when the indentation does not persist, e.g. lymphoedema, myxoedema. Figure 49 (A,B) Pitting oedema in a patient with cardiac failure.
Oedema
A depression (‘pit’) remains in the oedema for some minutes after firm fingertip pressure is applied.
