Leg Pain Physical examination – The initial encounter
The initial encounter with the patient suffering from leg pain is a critical departure point. The physician must develop a diagnostic impression by working through the history and physical findings in a systematic fashion. In the process he must reach a conclusion about the level of severity and danger to life and limb that is present and judge whether or not the patient requires expeditious referral, definitive testing or direct therapy. During the interview and exam differential diagnosis must of necessity be the foremost concern guiding questioning and probing, but with simultaneous assessment of the impact of the more generic issues of pain, functional disability, and danger as the evaluation proceeds.
As the disease process becomes clearer, a series of thresholds for diagnostic referrals or therapeutic action will be approached, with decisions at each turn. This diagnostic analysis and emergence of a problem-orientated plan are the essence of the initial assessment.
Questioning of the patient begins with a series of inquiries which results in a description of the duration, pattern, quality, and character of the pain syndrome. Concurrent and past illnesses should be documented. Appropriate details of occupational and daily activity should be established to illuminate the true functional impact of the leg pain. A complete history should result in a nearly diagnostic picture, leaving the physical examination and laboratory analysis to validate and prioritize a short list of diagnostic options developed on the basis of the patient’s story. The general line of questioning should follow the elements outlined in Table 1, emphasizing the differential points noted.
Severity is inferred from the duration, intensity, and constancy of the pain, all of which translate into some degree of functional impairment not only with ambulation but in severe cases with other aspects of function such as social life, emotional health, and sleep. Most times, the presence of danger is inferred from the initial history, brief as it may be on occasions when there is an air of urgency. For example, a frantic telephone call describing abrupt onset of a painful cold foot in a patient who recently had undergone peripheral arterial bypass surgery would clearly be placed at top priority. A more subtle element of danger may be introduced when pain or pain medications disturb fundamental functions like eating and sleeping. For example, an elderly frail patient with sciatica preventing sleep and requiring narcotic analgesics to the point of nausea and somnolence may be in a precarious position.
Detailed description of the pain pattern and character may be difficult to obtain in some instances when the patient is confused, upset or unable to communicate easily. In other instances a very clear description may be given, but with a complicated overlap in the story since more than one entity is in fact at play. Finally, the presentation may be atypical and fail to fit the diagnostic preconceptions of the examiner. The examiner must beware of the temptation to ‘put words into the patient’s mouth’ under these more difficult circumstances.
In general, the patient will volunteer a description of the character of the pain and its location at the outset as the chief complaint. For example, it is quite typical for a patient to answer ‘I have an ache in my knee’ or ‘my sole is on fire’ in response to an open-ended question at the outset. To the extent possible, the patient should be encouraged to locate the pain precisely to an anatomic structure of the leg such as a specific muscle or joint. The inquirer must keep in mind the fact that pain often radiates to areas adjacent to its source and that sometimes the source is not in the leg. In addition, pathology in one place may give rise to secondary symptoms elsewhere, as, for example, a sprained ankle on the right resulting in left hip and low back pain due to imbalanced limping. Many conditions, such as arthritis and vascular disease, are multifocal, with variable patterns of prominence among individuals and in the same patient at different times. For example, the location of claudication pain due to iliac artery disease may be limited to the calf muscle on a short walk but also involve the thigh and buttock muscles over longer stretches.
Stabbing pain is commonly used to describe an intense and focal sharp pain ‘like a knife’ which may ebb to a throbbing pain when less severe. An ache is generally a dull, less localized, and deep sensation. Patients may differentiate between ache and pain, as in ‘I don’t have any pain, just an ache’, at times closely associated with descriptions of stiffness. Cramps may be as intense as stabs, but are associated with a feeling of muscular tightness or rigidity. Shooting pain often comes through as an ‘electric shock’ down the leg. Burning is a superficial sensation once graphically described when severe as a ‘flamethrower’. Dysesthesia, often described as ‘pins and needles’, usually describes a deeper loss of normal sensation which shades into numbness. Weakness and heaviness are not truly painful, but are common complaints which may surface as part of a pain syndrome.
Temporality is of great diagnostic value but will usually require more elaborate probing by the questioner. The story of the onset of the symptoms fixes the perceived problem in time. The patient may be able to pinpoint an event or moment when the pain began, often with a distinct explanatory cause attributable by the patient. In many instances, on the other hand, the trouble may have started subtly and inexplicably with gradually increasing awareness to the point of sufficient concern to prompt a doctor visit. Circumstances such as trauma, unusual activity, travel, change in medications, and other illnesses are relevant details.
It is useful early in the inquiry to differentiate between constant or nearly constant pain and intermittent pain. Closer questioning will establish the behavior of the symptoms with various activities during the course of the day.
Many symptoms are always present, but at varying intensity depending on factors such as limb use, posture, and dependency as well as time of day, medications, and level of preoccupation by the patient. An important measure of severity is the degree to which the pain interferes with sleep. For example, sciatica and gout are notorious causes of constant misery both by night and by day. Arterial ischemia is also a prominent cause of sleeplessness with relief only by leg dependency which leads persevering patients to sleep sitting up in a chair. Other syndromes respond favorably to some extent to other modifications of posture or activity, with reciprocal modifications which exacerbate the pain. Intermittent pain syndromes usually involve the moving muscular and skeletal parts of the leg and follow a reasonably predictable pat-tern corresponding to activity. For example, intermittent claudication from arterial disease is brought on by muscular exercise and relieved by cessation of the exercise. Degenerative arthritis is aggravated predictably by weight bearing and mobility, and improved with recumbency and rest. Other forms of intermittent pain follow a more frustrating sporadic spontaneous pattern most typical of various forms of peripheral neuropathy.
Finally, the history must round out a complete picture of concurrent and past illnesses, habits, current medications, and allergies. As importantly, the history reveals a great deal about the patient’s reaction to the illness, his own explanation for the symptoms and his likely level of compliance with diagnostic and therapeutic alternatives.
The physical examination should seek to prove or disprove the working diagnostic hypothesis developed during the history. The extent of the exam includes the lower back, abdomen, and pelvis and may usefully employ the stethoscope, blood pressure cuff, rubber tourniquet, tape measure, hand-held Doppler ultrasound probe, magnifying glass, lancet and culture swab, tuning fork, and reflex hammer. A complete exam will require the patient to perform certain maneuvers while standing, bending over, and sitting and while reclining supine, lateral decubitus, and prone. In general, it is best to establish a routine approach, progressing from standing to sitting to reclining, covering each aspect of the various systems most favorably observed with each posture. Of course some patients will not be willing or able to cooperate fully or may have such compelling preoccupation with severe symptoms and findings that an abbreviated exam is appropriate. Comparison between the two lower extremities is particularly revealing.
Observation from multiple angles will detect obvious asymmetry in the legs as well as unusual posturing of the patient with upright weight bearing. Side lighting greatly assists in viewing the legs during standing. Twisting and bending at the waist to touch the toes reveals flexibility and uncovers the discomforts of herniated disk, sciatica and arthritis of the lower back and hip. Single leg standing, squatting, Romberg testing, heel-to-toe walking, and pivot-ing supplement the orthopedic and neurological exam. Repetitive toe-up exercise may produce claudication symptoms and corresponding decrease in ankle systolic pressure and pedal pulses confirming the presence of arterial disease. Venous disease involving the superficial veins is best seen while standing. Inguinal hernia is also best characterized with the patient upright and pain related to the cutaneous nerves of the lower abdomen (meralgia paresthetica) can be evaluated.
Sitting with the legs suspended allows a closer view of asymmetries in the calf, ankle, and feet. Dependent rubor is usually obvious, even when bilateral. The ankle and knee joint exams can be completed, along with strength assessment of the thigh and calf muscle groups and knee and ankle reflexes.
Passive straight leg raising, hip flexion, and rotation and hip joint strength are assessed from the supine position. The arterial exam is completed with pulse assessment, ankle pressure measurement in comparison with arm pressure, checking for femoral bruits, femoral and popliteal aneurysm, and distal pathology such as pallor with elevation and tissue threat. Chronic venous and lymphatic disease can be evaluated and comparative circumference at the thigh and calf measured. Skin problems can be scrutinized, examining open wounds and ulcers and sampling drainage or skin scrapings. The abdomen should be examined for masses, tenderness, abnormal pulsations or bruits. The muscle groups should be palpated to exclude tenderness, masses or increased tissue turgor. Popliteal and inguinal lymph nodes should be assessed.
Lateral decubitus positions are necessary to assess hip extension and to elicit psoas muscle spasm or inflammation. The prone position may be helpful in examining patients with buttock, popliteal fossa or heel findings.
The initial visit results in a plan for further diagnostic testing as necessary to confirm the first impression or to clarify the relative importance of each component of a syndrome arising from more than one entity. Some laboratory tests can be performed in the office or adjacent facility at the same visit for the convenience of the patient who, after all, has a hard time moving around. Non-invasive vascular laboratory studies of the arteries and veins, plain X-rays of bones and joints, fluid aspiration, cultures, and blood sampling can usually be done expeditiously with reports returned promptly in many instances. More sophisticated studies such as computed tomography or magnetic resonance imaging scans and angiography require more preparation and may most appropriately be preceded by specialty consultation.
As a result of the initial encounter the physician should have been able to gather enough information from the history, physical and simple laboratory testing to formulate at least a working diagnosis if not a firm diagnosis. At a minimum, the patient’s problems can be categorized by system and by severity to map out an early plan of action based on appropriate priorities.
Table 1 Danger signals.
Pain with pallor, pulselessness, paresthesia, paralysis
Pain with swelling, cyanosis
Painful red, indurated vein with fever
Pain in back radiating to groin
Long bone instability
Joint swelling, redness and fever
Acute arterial occlusion
Acute iliofemoral vein thrombosis Septic superficial thrombophlebitis Ruptured aortic or iliac aneurysm Fracture
Dislocation, severe ligament tear Septic arthritis
Cord, root or nerve compression
Depending on circumstances, such plans may entail further diagnostic study, a trial of therapy with return visit, preliminary therapy with referral to a consultant on an urgent or more casual timetable or hospitalization (Table 1). The posts which follow are designed to provide further background for choosing an accurate working diagnosis and an appropriate early manage-ment plan.