History
A 33-year-old woman attends the dermatology clinic with a 9-month history of unilateral leg swelling. Although the swelling is a cause of significant cosmetic concern, it is fairly asymptomatic. She is otherwise fit and well. She has travelled within France, Sweden and North America over the last 10 years but never visited the tropics. She is not taking any medication. There is no family history of similar swelling or varicose veins.
Examination
There is unilateral swelling of the entire left leg, including toes and extending to the groin. There is no involvement of the skin above the inguinal ligament. The oedema is non-pitting and non-tender. Over the distal anterior shin, the skin is erythematous, with evidence of early verrucous or cobble-stone change (Fig. 49.1), but there is no crust- ing, oozing or ulceration. There are no palpable lymph nodes. Examination of her cardiorespiratory system, abdo- men and pelvis was normal.
Questions
• What is the diagnosis?
• What are the potential causes?
• How would you investigate this patient further?
Medicine
The diagnosis in this patient is unilateral lymphoedema. Differential diagnoses would include deep venous thrombosis (DVT) (although one would anticipate more symptoms and a degree of pitting were that the case) and lipoedema (usually painful and symmetri-cally bilateral, rarely involving the feet or ankles, but occurring in young adult females).
Lymphatics are essential for clearing extravascular fluid and debris and for the transport of immunocompetent cells during the initiation of an immune response. Lymphoedema is an accumulation of protein-rich (1-5.5 g/mL) interstitial fluid due to impaired function- ing of the lymphatic channels. This high protein concentration favours the accumulation of water within the interstitium. This protein and fluid accumulation initiates a marked inflammatory reaction. Macrophage activity is increased, resulting in destruction of elas-tic fibers and production of fibrosclerotic tissue. Fibroblasts migrate into the interstitium and deposit collagen. The result of this inflammatory reaction is a change from the initial pitting oedema to the brawny non-pitting oedema that is characteristic of lymphoedema. Consequently, local immunologic surveillance is suppressed, and chronic infections, as well as malignant d egeneration to lymphangiosarcoma, may occur. Lymphoedema can be primary or secondary. The primary causes are abnormalities in the lymphatic system that are present at birth, although not always clinically evident until later in life. The causes of secondary lymphoedema include (1) infections, such as recurrent lymphangitis or cellulitis, or worldwide the most common cause, filariasis (the direct infestation of lymph nodes by the parasite Wuchereria bancrofti), (2) malignancy, (3) obesity, and (4) scarring following trauma or surgery. Further investigations should be undertaken to rule out occult malignancy and underlying infection (such as full blood count, CRP and ESR, renal and liver function, tumour mark-ers, abdominal and pelvic imaging studies). Lymphoscintigraphy can be used to assess the lymphatic system: it allows for detailed visualization of the lymphatic channels with minimal risk. The anatomy and the obstructed areas of lymphatic flow can be assessed. Ultrasonography can be used to evaluate the lymphatic and venous systems. Volumetric and structural changes are identified within the lymphatic system. Venous abnormalities such as DVT can be excluded based on ultrasonography findings. Lymphangiography, although once considered the ‘gold standard’ investigation of lymphatic obstruction, is now rarely performed because of potential adverse effects. In this case no evidence of occult malignancy was detected on physical examination or following bloods tests and imaging studies. The diagnosis therefore would be of a primary lymphoedema.
Primary lymphoedema has been subdivided into three entities: congenital lymphoedema, lymphoedema praecox, and lymphoedema tarda, depending on age at presentation. These conditions may be sporadic, with no family history, and usually involve the lower extremity almost exclusively. All are thought to result from a (usually localized) devel-opmental abnormality of the lymphatic system, which may only become apparent after a triggering event in later life. Overall women are more commonly affected than men. The management of lymphoedema is lifelong and is often onerous for the patient; it requires a high degree of compliance to prevent long-term complications. The principles of treatment are to eliminate protein stagnation and restore normal lymphatic circula-tion. Meticulous hygiene is essential as well as the avoidance of trauma, and a pragmatic approach to weight reduction. Long-term prophylactic antimicrobial treatment might be considered for patients with recurrent cellulitis or lymphangitis. A compression garment should be worn during the day with elevation of the affected limb overnight. Intermittent pneumatic pump compression therapy may also be instituted on an out-patient basis or in the home.
KEY POINTS
• Lymphoedema may be primary or secondary. Secondary lymphoedema can result from lymphatic obstruction due to infections, malignancy, obesity, or scarring following trauma or surgery.
• Prevention of complications is a long-term process.
• Surveillance for infection and malignant transformation is part of the long-term follow-up of affected individuals.
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