There are four well defined stages of lower limb ischaemia (Table 3.30).
Fig. 3.37 Coronary angiography in an RAO projection. The arrow indicates a severe discreet stenosis in the circumflex coronary artery. LM = left main. LAD = left anterior descending, Cx = circumflex.
TABLE 3.30 Classification ol lower limb ischaemia
ÍI Intermittent claudication
III Rest pain
IV Tissue loss (ulceration/gangrene)
Asymptomatic ischaemia. Lower limb ischaemia as defined by a reduced ankle : bracliia! pressure index (ABPI) is very common in Ihe middle-aged and elderly. Tliey may be asymptomatic either because they choose nol lo walk very far, or because their exercise tolerance is limited by other pathology. Such patients are at as high a risk from 'vascular" complications as those with symptoms and should be managed as if they have claudication.
Intermittent claudication f/CJ. This term refers to pain on walking due to arterial insufficiency. It is the commonest symptom of PAD. The pain typically occurs in the calf but may be felt in the thigh and/or buttock if Ihe obstruction to flow is sufficiently proximal. It is often described as a tightness or 'cramp-like'. Characteristically, the pain develops after a relatively constant distance, which will be shorter if walking uphill. On resting, the pain disappears completely within a few minutes but recurs on walking. The claudication distance described by the patient is often misleading with many patients underestimating their walking abilities. Rather than focusing upon absolute distances, it may be more useful to ask patients specific questions. Can they walk to the clinic from the bus stop or car park without slopping? Can they do their own shopping? The impact that claudication has on patients is clearly related to their age and lifestyle. The inability to walk 400 m would be a serious problem for a postman but perhaps not for an elderly man who simply wants to get across the road to the shops and the pub! It is also important to assess claudication in the context of the patient's other medical conditions. There is little point in subjecting patients with intermittent claudication to the risk of vascular surgery, only to find that they are now limited by osteoarthritis of the hip. angina or severe breathlessness.
Male patients wiLh gluteal claudication, due lo internal iliac disease, are almost invariably impotent. Enquiry into sexual activity (p. 11) should be made if not volunteered by such patients.
The term claudication is also used to denote pain in the leg on walking due to neurological and musculoskeletal disorders of the lumbar spine (neurogenic claudication) and due So venous outflow obstruction from the leg (venous claudication). However, these arc much less common than arterial claudication and can usually be distinguished on history and examination (see Table 3.32. p. 108).
Night/rest pain. Typically this lirst manifests itself as night pain. The patient goes to bed and falls asleep only to be woken 1-2 hours later by pain in the foot, usually in the instep. This is due to the loss on recumbency of the beneficial effects of gravity on lower limb perfusion. Sleep is also associated with a reduction in heart rate, blood pressure and cardiac output. Patients usually find that they only obtain relief by hanging their leg out of bed or by getting up and walking around. When the patient returns to bed. symptoms recur. The pain and sleep disturbance may be so debilitating that the patient lakes to sleeping in a chair, This leads to dependent oedema and the increased interstitial tissue pressure causes further reduction in tissue perfusion, and more pain. Rest pain usually indicates the presence of multi-level disease.
Tissue loss (ulceration and/or gangrene). Patients with rest pain caused by arterial insufficiency are frequently termed as having critical limb ischaemia. In such patients trivial injuries will fail to heal and provide a portal of entry for bacteria leading to gangrene and/or ulceration. Without revascularisation the ischaemia will rapidly progress
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.