Lymphoedema
Defination
Oedema is due primarily to defective lymphatic drainage in the presence
of (near) normal net capillary filtration.
Fig. 17.1 Acute
Iymphangitis of the arm. Erythematous streaks extend from the site of primary
infection on the volar aspect of the forearm to epicondylar nodes at the elbow
and thence to enlarged and tender axillary lymph nodes.
Pathophysiology
Lymphoedema is the end result of insufficient lymphatic outflow due to
aplasia, hypoplasia, primary decreased lymphatic contractility (with or without
valvular insufficiency) or inflammatory obliteration. Lymphatic hypertension
occurs and leads to distension with secondary impairment of contractility and
valvular competence. Lymphostasis leads to the accumulation of fluid, proteins,
growth factors and other active peptide moieties, glycosaminoglycans and
particulate matter, including bacteria. As a consequence, there is increased
collagen production by fibroblasts, an accumulation of inflammatory cells
(predominantly macrophages and lymphocytes) and activation of keratinocytes. The
end result is protein-rich oedema fluid, increased deposition of ground
substance, subdermal fibrosis, and dermal thickening and proliferation.
Cross-sectional
imaging of the affected limb by means of computerised tomography (CT) or
magnetic resonance imaging clearly indicates that lymphoedema, unlike all other
causes of oedema, is confined to the epifascial space comprising the skin and
subcutaneous tissues. Although muscle compartments may be hypertrophied as a
result of the increased work involved in limb movement, they are
characteristically free of oedema.
Lymphoedema was originally classified by Allen in 1934 who subdivided it
into primary lymphoedema, in which the cause is unknown (or at least unproved),
and secondary lymphoedema, in which there is a clear aetiology (Table
17.1).
Primary lymphoedema is usually further subdivided on the
History
The age of onset of painless swelling, together with the presence or
absence of a family history or coexistent pathology, will allow differentiation
of primary from secondary lymphoedema to be made in most cases. It is
important to remember that in developed countries lymphoedema is a relatively
uncommon cause of limb swelling (Table 17.3).
Signs
Unlike other types of oedema, lymphoedema characteristically involves
the foot (Fig. 17.2). The contour of the ankle is lost through infilling of the
submalleolar depressions, a ‘buffalo hump’ forms on the dorsum of the foot,
the toes appear ‘square’ owing to confinement of footwear and the skin on
the dorsum of the toes cannot be pinched because of subcutaneous fibrosis (Stemmer’s
sign). Lymphoedema usually spreads proximally to knee level and less commonly
affects the whole leg (Fig. 17.3). Lymphoedema will pit easily at first but,
with time, fibrosis and dermal thickening prevent pitting except following
prolonged pressure. Chronic eczema, fungal infection of the skin (dermatophytosis)
and nails (onychomycosis), fissuring, verrucae and papillae are frequently seen
in advanced conditions. Frank ulceration is