Leg swelling must never be assumed to be due to peripheral oedema. A definite diagnosis of the underlying cause must be made and a careful history and examination, along with appropriate confirmatory tests, are essential. Swelling of the legs may be either unilateral or bilateral:
- Bilateral swelling is usually due to systemic conditions, eg cardiac failure, and unilateral is often due to local trauma, venous disease or lymphatic disease.
- Unilateral leg swelling is more often due to local causes, eg deep vein thrombosis but bilateral swelling from systemic causes may be much more obvious on one side than the other and therefore appears to be unilateral swelling.
- Venous: varicose veins, obstruction of venous return, eg pregnancy, pelvic tumours, inferior vena cava obstruction, post-phlebitis.
- Lymphoedema: lymphatic obstruction due to malignancy, post-irradiation, surgery, recurrent infection, lymphatic hypoplasia, filariasis.
- Congenital malformations, eg arteriovenous fistula.
- Stasis: paralysis, poor mobility and dependency, obesity.
The nature of the presentation will give essential clues in establishing the diagnosis in terms of whether unilateral or bilateral, speed of onset (see list under 'Causes', above) and associated symptoms - for example:
- Orthopnoea, paroxysmal nocturnal dyspnoea: heart failure.
- Diarrhoea or other bowel dysfunction: protein-losing enteropathy.
- Painful swollen calf: deep vein thrombosis or inflammation, eg cellulitis, osteomyelitis.
- Pigmentation: venous insufficiency.
- Periorbital oedema: renal failure.
- Pelvic mass or pregnancy.
- Urinalysis: proteinuria suggests renal cause.
- FBC: high white cell count in infection; anaemia.
- Biochemistry: renal function and electrolytes (raised creatinine in renal failure); LFTs (impaired liver function and associated low albumin); glucose (infection associated with diabetes); TFTs (hypothyroidism).
- Clotting screen: abnormal clotting associated with spontaneous haematoma.
- CXR: pulmonary oedema.
- D-dimer blood test: D-dimers are products of fibrin degradation and are raised in patients with venous thromboembolism. Sensitivity of the test is high but specificity is poor.
- ECG: heart failure.
- Ultrasound, CT scan: haematoma, tumour, abdominal or pelvic mass.
- Duplex Doppler, venography: deep vein thrombosis, arteriovenous fistula.
- Lymphangiography: demonstrates cause of lymphoedema and whether due to hypoplasia or obstruction.
- Lymph node biopsy: infection, tumour.
- Other investigations may include renal biopsy, echocardiogram.
Management is directed at identification and treatment of the underlying cause.
Further reading & references
- Diskin CJ, Stokes TJ, Dansby LM, et al; Towards an understanding of oedema. BMJ. 1999 Jun 12;318(7198):1610-3.
- Turpie A, Chronic Venous Insufficiency and Postphlebitic Syndrome, The Merck Manual, 2008
- Gorman WP, Davis KR, Donnelly R; ABC of arterial and venous disease. Swollen lower limb-1: general assessment and BMJ. 2000 May 27;320(7247):1453-6.
- Ely JW, Osheroff JA, Chambliss ML, et al; Approach to leg edema of unclear etiology. J Am Board Fam Med. 2006 Mar-Apr;19(2):148-60.
- O'Brien JG, Chennubhotla SA, Chennubhotla RV; O'Brien JG, Chennubhotla SA, Chennubhotla RV; Treatment of edema. Am Fam Physician. 2005 Jun 1;71(11):2111-7.
|Original Author: Dr Colin Tidy||Current Version: Dr Laurence Knott||Peer Reviewer: Dr Hannah Gronow|
|Last Checked: 19/04/2012||Document ID: 2826 Version: 22||© EMIS|
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