++
The older the patient, the more likely it is that arterial disease with intermittent claudication and neurogenic claudication due to spinal canal stenosis will develop. Other important problems of the elderly include degenerative joint disease, such as osteoarthritis of the hips and knees, muscle cramps, herpes zoster, Paget disease, polymyalgia rheumatica (affecting the upper thighs) and sciatica.
+++
Spinal causes of leg pain
++
Problems originating from the spine are an important, yet at times complex, cause of pain in the leg.
++
++
++
Various pain patterns are presented in FIGURES 66.3 and 66.4.
++
Nerve root pain from a prolapsed disc is a common cause of leg pain. A knowledge of the dermatomes of the lower limb (see FIG. 66.1) provides a pointer to the involved nerve root, which is usually L5 or S1 or both. The L5 root is invariably caused by an L4–5 disc prolapse and the S1 root by an L5–S1 disc prolapse. The nerve root syndromes are summarised in TABLE 66.3.
++
++
A summary of the physical examination findings for the most commonly involved nerve roots is presented in TABLE 66.3.
++
See CHAPTER 38. Sciatica is defined as pain in the distribution of the sciatic nerve or its branches (L4, L5, S1, S2, S3) caused by nerve pressure or irritation. Most problems are due to entrapment neuropathy of a nerve root, in either the spinal canal (as outlined above) or the intervertebral foramen.
++
It should be noted that back pain may be absent and peripheral symptoms only will be present.
++
A protracted course can be anticipated, in the order of 12 weeks (see CHAPTER 38). The patient should be reassured that spontaneous recovery can be expected. A trial of conservative treatment would be recommended thus:
++
back care education
relative bed rest if very painful only (2 days is optimal)—a firm base is ideal
return to activities of daily living ASAP
analgesics (avoid narcotic analgesics if possible)
NSAIDs (2 weeks is recommended)
basic exercise program, including swimming
traction can help, even intermittent manual
++
Referral to a therapist of your choice (e.g. physiotherapist) may be advisable. Conventional spinal manipulation is usually contraindicated for radicular sciatica. If the patient is not responding or the circumstances demand more active treatment, an epidural anaesthetic injection is appropriate. Surgical consultation is indicated for a severe or progressive neurological deficit.
++
If a trial of NSAIDs, rest and physiotherapy has not brought significant relief, an epidural anaesthetic (lumbar or caudal) using half-strength local anaesthetic (e.g. 0.25% bupivacaine HCl) and a depot corticosteroid (e.g. triamcinolone) is advisable. The lumbar route under image intensification is preferred.
+++
Lumbar spinal canal stenosis (LSS)3
++
LSS is narrowing of the spinal canal resulting in pressure on the sciatic nerve roots and possibly the spinal canal and cord. It typically occurs in people aged over 50 years with a history of spinal degenerative changes, including osteoarthritis (see FIG. 38.9), but LSS may be congenital.
++
The symptoms are as outlined for neurogenic claudication in TABLE 66.2. Pain, which is usually bilateral, is in the proximal-leg buttocks, thighs and legs, radiating distally. Some 50% remain clinically stable, 25% deteriorate and about 25% improve with time. Conservative treatment includes relative rest, specific exercises, analgesics and agents for neuropathic pain. There is no evidence of the value of epidural corticosteroid injections or oral corticosteroids. Surgical consultation is indicated for severe or progressive neurological deficit or progressive pain,. The risk of surgical complications increases with age.
++
Referred pain in the leg can arise from disorders of the SIJs or from spondylogenic disorders. It is typically dull, heavy and diffuse. The patient uses the hand to describe its distribution compared with the use of fingers to point to radicular pain.
++
Non-radicular or spondylogenic pain originates from any of the components of the vertebrae (spondyles), including joints, the intervertebral discs, ligaments and muscle attachments. An important example is distal referred pain from disorders of the apophyseal joints, where the pain can be referred to any part of the limb as far as the calf and ankle but most commonly to the gluteal region and proximal thigh (see FIG. 66.4).
++
Another source of referred pain is that caused by compression of a bulging disc against the posterior longitudinal ligament and dura. The pain is typically dull, deep and poorly localised. The dura has no specific dermatomal localisation, so the pain is usually experienced in the low back, sacroiliac area and buttocks. Less commonly, it can be referred to the coccyx, groin and both legs down to the calves. It is not referred to the ankle or the foot.
+++
Sacroiliac dysfunction
++
This typically causes a dull ache in the buttock, but it can be referred to the iliac fossa, groin or posterior aspects of the thighs (see CHAPTER 65). It rarely radiates to or below the knee. It may be caused by inflammation (sacroiliitis) or mechanical dysfunction. The latter must be considered in a postpartum woman presenting with severe aching pain present in both buttocks and thighs.
+++
Nerve entrapment syndromes
++
Entrapment neuropathy can result from direct axonal compression or can be secondary to vascular problems, but the main common factor is a nerve passing through a narrow rigid compartment where movement or stretching of that nerve occurs under pressure.
++
Pain at rest (often worse at night)
Variable effect with activity
Sharp, burning pain
Radiating and retrograde pain
Clearly demarcated distribution of pain
Paraesthesia may be present
Tenderness over nerve
May be positive Tinel sign
+++
Meralgia paraesthetica
++
This is the commonest lower limb entrapment and is due to the lateral femoral cutaneous nerve of the thigh being trapped under the lateral end of the inguinal ligament, 1 cm medial to the ASIS.4
++
The nerve is a sensory nerve from L2 and L3. It occurs mostly in middle-aged people, due mainly to thickening of the fibrous tunnel beneath the inguinal ligament, and is associated with obesity, pregnancy, ascites or local trauma such as belts, trusses and corsets. Its entrapment causes a burning pain with associated numbness and tingling (see FIG. 66.3).
++
The distribution of pain is confined to a localised area of the lateral thigh and does not cross the midline of the thigh.
+++
Differential diagnosis
++
++
Injection of corticosteroid medial to the ASIS, under the inguinal ligament
Surgical release (neurolysis) if refractory
Treat the cause (e.g. weight reduction, constricting belt, corset)
++
Note: Meralgia paraesthetica often resolves spontaneously.
+++
Peroneal nerve entrapment
++
The common peroneal (lateral popliteal) nerve can be entrapped where it winds around the neck of the fibula or as it divides and passes through the origin of the peroneus longus muscle 2.5 cm below the neck of the fibula. It is usually injured, however, by trauma or pressure at the neck of the fibula.
++
Pain in the lateral shin area and dorsum of the foot
Sensory symptoms in the same area
Weakness of eversion and dorsiflexion of the foot (described by patients as ‘a weak ankle’)
+++
Differential diagnosis
++
++
+++
Tarsal tunnel syndrome
++
This is an entrapment neuropathy of the posterior tibial nerve in the tarsal tunnel beneath the flexor retinaculum on the medial side of the ankle. The condition is due to dislocation or fracture around the ankle or tenosynovitis of tendons in the tunnel from injury, or rheumatoid arthritis and other inflammations.
++
A burning or tingling pain in the toes and sole of the foot, occasionally the heel
Retrograde radiation to the calf, perhaps as high as the buttock
Numbness is a late symptom
Discomfort often in bed at night and worse after standing
Removal of shoe may give relief
Sensory nerve loss variable, may be no loss
Tinel test (finger or reflex hammer tap over nerve below and behind medial malleolus) may be positive
Tourniquet applied above ankle may reproduce symptoms
++
The diagnosis is confirmed by electrodiagnosis.
++
Relief of abnormal foot posture with orthotics
Corticosteroid injection into tunnel
Decompression surgery if other measures fail
+++
Vascular causes of leg pain
+++
Occlusive arterial disease
++
Risk factors for peripheral vascular disease (for development and deterioration):
++
++
++
beta-blocking drugs
anaemia
+++
Acute lower limb ischaemia
++
Sudden occlusion is a dramatic event that requires immediate diagnosis and management to save the limb.
++
Embolism—peripheral arteries
Thrombosis: major artery, popliteal aneurysm
Traumatic contusion (e.g. postarterial puncture)
++
The symptoms and signs of acute embolism and thrombosis are similar, although thrombosis of an area of atherosclerosis is often preceded by symptoms of chronic disease (e.g. claudication). The commonest site of acute occlusion is the common femoral artery (see FIG. 66.5).
++
+++
Signs and symptoms—the 6 Ps
++
Pain
Pallor
Paraesthesia or numbness
Pulselessness
Paralysis
‘Perishing’ cold
++
The pain is usually sudden and severe and any improvement may be misleading. Sensory changes initially affect light touch, not pinprick. Paralysis (paresis or weakness) and muscle compartment pain or tenderness are most important and ominous signs.
++
Other signs include mottling of the legs, collapsed superficial veins, and no capillary return. If the foot becomes dusky purple and fails to blanch on pressure, irreversible necrosis has occurred.
++
Note: Look for evidence of atrial fibrillation.
+++
Examination of arterial circulation
++
This applies to chronic ischaemia and also to acute ischaemia.
+++
Skin and trophic changes
++
Note colour changes, hair distribution and wasting. Note the temperature of the legs and feet with the backs of your fingers.
++
It is important to assess four pulses carefully (see FIG. 66.6). Note that the popliteal and posterior tibial pulses are difficult to feel, especially in obese subjects.
++
++
Femoral artery. Palpate deeply just below the inguinal ligament, midway between the ASIS and the symphysis pubis. If absent or diminished, palpate over abdomen for aortic aneurysm.
++
Popliteal artery. Flex the leg to relax the hamstrings. Place fingertips of both hands to meet in the midline. Press them deeply into the popliteal fossa to compress artery against the upper end of the tibia (i.e. just below the level of the knee crease). Check for a popliteal aneurysm (very prominent popliteal pulsation).
++
Posterior tibial artery. Palpate, with curved fingers, just behind and below the tip of the medial malleolus of the ankle.
++
Dorsalis pedis artery. Feel at the proximal end of the first metatarsal space just lateral to the extensor tendon of the big toe.
++
Look for evidence of oedema: pitting oedema is tested by pressing firmly with your thumb for at least 5 seconds over the dorsum of each foot, behind each medial malleolus and over the shins.
+++
Postural colour changes (Buerger test)
++
Raise both legs to about 60° for about 1 minute, when maximal pallor of the feet will develop. Then get the patient to sit up on the couch and hang both legs down.4
++
Note: Comparing both feet, check the time required for return of pinkness to the skin (normally less than 10 seconds) and filling of the veins of the feet and ankles (normally about 15 seconds). Look for any unusual rubor (dusky redness) that takes a minute or more in the dependent foot. A positive Buerger test is pallor on elevation and rubor on dependency and indicates severe, chronic ischaemia.
+++
Auscultation for bruits after exercise
++
Listen over abdomen and femoral area for bruits.
++
Note: Neurological examination (motor, sensory, reflexes) is normal unless there is associated diabetic peripheral neuropathy.
++
Golden rules: Occlusion is usually reversible if treated within 4 hours (i.e. limb salvage). It is often irreversible if treated after 6 hours (i.e. limb amputation).
++
Intravenous heparin (immediately) 5000 U
Emergency embolectomy (ideally within 4 hours):
– under general or local anaesthesia
– through an arteriotomy site in the common femoral artery
– embolus extracted with Fogarty balloon or catheter
or
Stenting of vessels (a good modern option)—discuss this with an interventional cardiovascular physician or interventional radiologist (less invasive and less expensive)
Angioplasty
Arterial bypass if acute thrombosis in chronically diseased artery
In selected cases, thrombolysis with streptokinase or urokinase appropriate
Amputation (early) if irreversible ischaemic changes
Lifetime anticoagulation with warfarin will be required
++
Note: An acutely ischaemic limb is rarely life-threatening in the short term. Thus, even in the extremely aged, demented or infirm, a simple embolectomy is not only worthwhile but also is usually the most expedient treatment option.
+++
Chronic lower limb ischaemia
++
Chronic ischaemia caused by gradual arterial occlusion can manifest as intermittent claudication, rest pain in the foot or overt tissue loss—ulceration, gangrene (see FIG. 66.7).
++
++
Intermittent claudication is a pain or tightness in the muscle on exercise (Latin claudicare, to limp), relieved by rest. Rest pain is a constant severe burning-type pain or discomfort in the forefoot at rest, typically occurring at night when the blood flow slows down.
++
The main features are compared in TABLE 66.4.
++
+++
Intermittent claudication
++
The level of obstruction determines which muscle belly is affected (see FIGS 66.2 and 66.6).
+++
Proximal obstruction (e.g. aortoiliac)
++
Pain in the buttock, thigh and calf, especially when walking up hills and stairs
Persistent fatigue over whole lower limb
Impotence is possible (Leriche syndrome)
+++
Obstruction in the thigh
++
Superficial femoral (the commonest) causes pain in the calf (e.g. 200–500 m), depending on collateral circulation
profunda femoris → claudication at about 100 m
multiple segment involvement → claudication at 40–50 m
++
Atherosclerosis (mainly men over 50, smokers)
Embolisation (with recovery)
Buerger disease: affects small arteries, causes rest pain and cyanosis (claudication uncommon)
Popliteal entrapment syndrome (<40 years of age)
++
Note: The presence of rest pain implies an immediate threat to limb viability.
++
FBE: exclude polycythaemia and thrombocytosis
Colour Doppler ultrasound: measure resting ankle systolic BP; determine ankle/brachial index; normal value 0.9–1.1
Angiography: the gold standard, reserved for proposed intervention
Digital subtraction angiography (developing)