Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Chronic leg swelling
There are various conditions that can cause chronic lower limb swelling ( Box 18.1 ). The three most common are chronic venous insufficiency (CVI), lymphoedema and dependent oedema, which may be associated with inactivity and obesity. This chapter explores these three conditions further.
Box 18.1
Differential diagnosis of chronic leg swelling
Venous disease
-
Primary varicose veins
-
Primary deep venous incompetence
-
Post-thrombotic syndrome
-
Arteriovenous malformations
Lymphoedema
-
Primary
-
Secondary
General disease
-
Lipidema
-
Congestive cardiac failure
-
Pre-tibial myxoedema
-
Nephrotic syndrome
-
Hepatic failure
Tumours
-
Pelvic tumours causing extrinsic compression
Drugs
-
Dependency
Chronic venous insufficiency
CVI encompasses disease of the lower limb veins in which venous return is impaired over a number of years, by reflux, obstruction or calf muscle pump failure. This leads to sustained venous hypertension and ultimately clinical complications including oedema, eczema, lipodermatosclerosis and when severe, ulceration.
Clinical features
The clinical features of CVI include skin changes, varicose veins, swelling, pain and ulceration and pain.
Skin changes
Varicose eczema presents as dry, scaly and itchy skin. The skin becomes friable and may become infected following scratching. Pigmentation, caused by the deposition of haemosiderin in the tissues, produces a brown discoloration characteristic of CVI, which together with fibrosis leads to the clinical picture of lipodermatosclerosis around the ankle ( Fig. 18.1 ). There may also be loss of pigmentation resulting in pale skin changes called atrophie blanche .
Varicose veins
Varicose veins may be present and a history of previous varicose vein treatment should be sought. The absence of visible varicose veins does not exclude the presence of significant superficial reflux. Varicose veins on the lower anterior abdominal wall are a sign of inferior vena cava or iliac vein obstruction and the patient should be examined standing to identify these.
Pain
The patient may complain of a general ache and heaviness in the leg after long periods of standing. This is worse towards the end of the day but improves with elevation or bed rest.
A history of deep vein thrombosis (DVT) should be sought. Venous claudication is an uncommon symptom that is usually caused by iliofemoral vein occlusion or a significant stenosis. The symptoms differ from arterial claudication because the increase in arterial inflow during exercise combined with decreased outflow results in distension of the limb, giving rise to generalised pain and a severe bursting sensation in the leg. The pain often requires elevation for 10–20 minutes for relief after cessation of exercise.
Swelling
Swelling is caused by an accumulation of oedematous fluid, which is initially pitting, but as the disease progresses subcutaneous fibrosis and induration occur. If there is any break in the skin, this can lead to copious exudation of fluid.
Ulceration
Ulceration is often precipitated by minor trauma and venous ulcers occur predominantly on the lower leg, more commonly around the medial aspect of the ankle. There may be surrounding eczema or pigmentation and frequently exudation of fluid can cause maceration of the surrounding skin. In patients presenting with lower limb ulceration, approximately 80% , will have evidence of venous disease and 10–25% of limbs will have Doppler-verified arterial disease. Approximately 12% will have co-existing diabetes or rheumatoid arthritis. Immobility is often a contributory cause and can also cause stasis ulceration in isolation. As with pain a history of DVT should be sought as ulcers are a common feature of post-thrombotic syndrome (PTS).
Epidemiology
The prevalence of CVI in the adult population lies between 2% and 9% and may be higher in males than females. , The most serious feature of CVI is ulceration, which is a distressing and debilitating condition. Leg ulcers affect approximately 1% of the adult population in developed countries, with 50% of ulcers having been present for more than 12 months, and 72% are recurrent. Within the UK, Australia, Sweden and Italy, overall rates for active ulceration range from 0.15–0.5% and increase with age. In the UK, the current total cost to the National Health Service is estimated to be around £1 billion a year.
Aetiology
To understand CVI, the changes that occur in both the larger veins (macrocirculation) and the capillary bed (microcirculation) must be considered.
Macrocirculation
During exercise in the normal individual, effective contraction of the calf muscles combined with vein patency and valvular competence aids venous return and reduces venous pressure in the lower leg from about 90 mmHg to 30 mmHg. Failure of any of these mechanisms can result in post-ambulatory venous hypertension, which is accepted as the underlying haemodynamic abnormality in CVI. The recognised causes are outlined in Box 18.2 .
Box 18.2
Causes of venous hypertension
Deep and superficial reflux
Most venous ulcers were thought to be secondary to a previous DVT but duplex scanning has demonstrated that some patients have primary deep venous reflux. Isolated superficial venous incompetence without deep venous incompetence occurs in between 31% and 57% of patients with venous ulceration.
Perforating vein reflux
The contribution of incompetent perforators to the development of CVI remains controversial. Isolated perforator incompetence occurs in only 2–4% of limbs with skin changes, and perforator incompetence is usually associated with reflux in the superficial or deep systems. However, the prevalence of incompetent perforators increases linearly with the clinical severity of CVI. There has been a recent trend towards treatment of incompetent perforating veins with laser or radiofrequency ablation (RFA), but the indications for this remain uncertain. In those cases where superficial and perforator reflux coincide, treating only the former results in healing rates of 95%.
Microcirculation
The pathophysiology is still not fully understood but the following two hypotheses exist:
- 1.
White cell trapping hypothesis. Increased venous pressures lead to white blood cell plugging of capillaries, adherence of white cells to the endothelium and release of proteolytic enzymes. This leads to increased capillary permeability and tissue damage causing ulceration.
- 2.
Fibrin cuff hypothesis. A rise in venous pressure causes widening of the pores between endothelial cells. This results in leakage of fibrinogen out of the intravascular compartment into the tissues, which polymerises to form fibrin. A defective interstitial fibrinolytic system may also contribute to the build-up of fibrin. Fibrin ‘cuffs’ form around the capillaries, which acts as a barrier to oxygen, resulting in local tissue ischaemia and cell death, producing ulceration.
Matrix metalloproteinases help remodel the extracellular matrix by protein degradation, and enhanced matrix metalloproteinase activity has been demonstrated in lipodermatosclerosis. This may also contribute to the development of ulceration.
Classification
CVI involves a variety of anatomical and physiological abnormalities and so a standardised system is required to allow uniformity of reporting.
A classification was developed in 1994 by an international consensus conference under the auspices of the American Venous Forum and recommendations for change were made in 2004 and updated again in 2020.
This includes clinical signs (C), aetiology (E), anatomical distribution (A) and pathophysiological condition (P) and is therefore known by the acronym CEAP. This system is helpful in comparing limbs for the purposes of research, although it is rather unwieldy for everyday use ( Box 18.3 ).
Box 18.3
CEAP classification
Clinical signs (C 0–6 )
-
Limbs are placed into one of seven clinical classes according to objective signs as follows:
-
Class 0: no visible or palpable signs of venous disease
-
Class 1: telangiectases, reticular veins, malleolar flare
-
Class 2: varicose veins
-
Class 3: oedema without skin changes
-
Class 4a: pigmentation or eczema class 4b, lipodermatosclerosis or atrophie blanche
-
Class 5: skin changes as aforementioned with healed ulceration
-
Class 6: skin changes as aforementioned with active ulceration
-
-
Each limb is further classified as asymptomatic (A) or symptomatic (S)
Aetiology (E C,P,S,N )
-
This classification refers to congenital (C), primary (P; unknown cause but not congenital), secondary (S; acquired) and no aetiology identified (N). These groups are mutually exclusive
Anatomical distribution (A S,D,P,N )
-
This refers to superficial (S), deep (D), perforating (P) veins and no venous location identified (N). More than one system may be involved
Pathophysiological condition (P R,O,N )
-
This refers to reflux (R) or obstruction (O), or both may be present. P N implies no venous pathophysiology identified
Investigation
Patients often present with mixed arterial and venous disease and so ankle–brachial pressure indices must be recorded if foot pulses are weak or absent and when compression therapy is being considered. The investigation of the venous disease is discussed later.
Hand-held Doppler
Continuous-wave hand-held Doppler using an 8-MHz probe is a useful outpatient tool in screening for arterial and venous disease. Its limitations are that the exact vein being insonated is unknown, it is operator dependent and the significance of reflux of short duration may be uncertain.
Duplex scanning
Duplex is an important investigation of lower limb venous disease and is now first line. Modern equipment allows easy identification of normal and abnormal venous anatomy, along with the presence of venous reflux. It is also extensively used for the diagnosis of DVT.
An international consensus document recommends duplex scanning as an essential investigation for patients with CVI.
Venography
Venography is invasive and to a large extent has been superseded by duplex scanning for the investigation of venous disease of the lower limb. Venography still has a place in the diagnosis of upper limb DVT when ultrasound is inconclusive and clinical suspicion persists and in patients with post-thrombotic limb where an obstruction in the iliac veins and inferior vena cava, is not readily visualised by ultrasound. With the increased use of deep endovenous therapy, however, to treat such lesions, axial imaging with either computed tomography (CT) or magnetic resonance (MR) venography is often used for pre-operative planning.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here