Oedema in obesity; role of structural lymphatic abnormalities

Oedema is a common finding in obesity and its cause is not always clear. Possible causes include impairment of cardiac, respiratory and/or renal function, chronic venous insufficiency and lymphatic problems. Lymphoscintigraphy is the best method to detect structural lymphatic abnormalities that can cause lymphoedema. We reviewed 49 female subjects with pitting oedema who had undergone lymphoscintigraphy, divided in three groups. The first group was comprised of severely obese patients in whom cardiorespiratory causes for oedema had been excluded. The second group consisted of non-obese patients with recognized causes for oedema and the third group was non-obese patients with 'idiopathic' oedema. A standard classification was used to interpret lymphoscintigraphy results. The frequency and severity of lymphoscintigraphic abnormalities was greatest in patients with clinical diagnoses of oedema related to 'recognized causes' (any abnormality in 50% of legs with obstruction in 22%). Obese patients and those with 'idiopathic'oedema had fewer (P=0.02 for both) and milder lymphoscintographic abnormalities (any abnormality 32 and 25%, respectively, obstruction 5 and 3%, respectively), and although the clinical oedema was invariably bilateral, the lymphoscintigraphy abnormalities were usually unilateral. In conclusion, structural lymphoscintigraphic abnormalities are uncommon in obesity and do not closely correlate with the clinical pattern of oedema.