Approach to Articular and Musculoskeletal Disorders (Disorders of the Joints and Adjacent Tissues) (Rheumatology) Part 1

Musculoskeletal complaints account for >315 million outpatient visits per year. Recent surveys by the Centers for Disease Control and Prevention suggest that 33% (69.9 million) of the U.S. population is affected by arthritis or joint disorders. Many of these are self-limited conditions requiring minimal evaluation and only symptomatic therapy and reassurance. However, in some patients, specific musculoskeletal symptoms or their persistence may herald a more serious condition that requires further evaluation or laboratory testing to establish a diagnosis or document the extent and nature of the pathologic process. The goal of the musculoskeletal evaluation is to formulate a differential diagnosis that leads to an accurate diagnosis and timely therapy, while avoiding excessive diagnostic testing and unnecessary treatment (Table 17-1). There are several urgent conditions that must be diagnosed promptly to avoid significant morbid or mortal sequelae. These “red flag” diagnoses include septic arthritis, acute crystal-induced arthritis (e.g., gout), and fracture. Each may be suspected by its acute onset and monarticular or focal presentation (see below).

Individuals with musculoskeletal complaints should be evaluated with a thorough history, a comprehensive physical examination, and, if appropriate, laboratory testing. The initial encounter should determine whether the musculoskeletal complaint is (1) articular or nonarticular in origin, (2) inflammatory or noninflammatory in nature, (3) acute or chronic in duration, and (4) localized or widespread (systemic) in distribution.


With such an approach and an understanding of the pathophysiologic processes that underlie musculoskeletal complaints, a diagnosis can be made in the vast majority of individuals. However, some patients will not fit immediately into an established diagnostic category. Many musculoskeletal disorders resemble each other at the outset, and some may take weeks or months to evolve into a readily recognizable diagnostic entity. This consideration should temper the desire to establish a definitive diagnosis at the first encounter.

Articular Versus Nonarticular

The musculoskeletal evaluation must discriminate the anatomic origin(s) of the patient’s complaint. For example, ankle pain can result from a variety of pathologic conditions involving disparate anatomic structures, including gonococcal arthritis, calcaneal fracture, Achilles tendinitis, cellulitis, and peripheral neuropathy. Distinguishing between articular and nonarticular conditions requires a careful and detailed examination.

TABLE 17-1

EVALUATION OF PATIENTS WITH MUSCULOSKELETAL COMPLAINTS

Goals

Accurate diagnosis

Timely provision of therapy

Avoidance of unnecessary diagnostic testing

Approach

Anatomic localization of complaint (articular vs

nonarticular)

Determination of the nature of the pathologic process

(inflammatory vs. noninflammatory)

Determination of the extent of involvement (monarticular,

polyarticular, focal, widespread)

Determination of chronology (acute vs chronic)

Consider the most common disorders first

Formulation of a differential diagnosis

Articular structures include the synovium, synovial fluid, articular cartilage, intraarticular ligaments, joint capsule, and juxtaarticular bone. Nonarticular (or periarticular) structures, such as supportive extraarticular ligaments, tendons, bursae, muscle, fascia, bone, nerve, and overlying skin, may be involved in the pathologic process. Although musculoskeletal complaints are often ascribed to the joints, nonarticular disorders (rather than articular) more frequently underlie such complaints. Distinguishing between these potential sources of pain may be challenging to the unskilled examiner. Articular disorders may be characterized by deep or diffuse pain, pain or limited range of motion on active and passive movement, and swelling (caused by synovial proliferation, effusion, or bony enlargement), crepitation, instability, “locking,” or deformity. By contrast, nonarticular disorders tend to be painful on active, but not passive (or assisted), range of motion; demonstrate point or focal tenderness in regions adjacent to articular structures; and have physical findings remote from the joint capsule. Moreover, nonarticular disorders seldom demonstrate swelling, crepitus, instability, or deformity.

Inflammatory Versus Noninflammatory Disorders

In the course of a musculoskeletal evaluation, the examiner should determine the nature of the underlying pathologic process and whether inflammatory or noninflammatory findings exist. Inflammatory disorders may be infectious (infection with Neisseria gonor-rhoeae or Mycobacterium tuberculosis), crystal induced (gout, pseudogout), immune related [rheumatoid arthritis (RA), systemic lupus erythematosus (SLE)], reactive (rheumatic fever, Reiter’s syndrome), or idiopathic. Inflammatory disorders may be identified by any of the four cardinal signs of inflammation (erythema, warmth, pain, or swelling), systemic symptoms (fatigue, fever, rash, weight loss), or laboratory evidence of inflammation [elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP),thrombocyto-sis, anemia of chronic disease, or hypoalbuminemia]. Articular stiffness commonly accompanies chronic musculoskeletal disorders. However, the severity and duration of stiffness may be diagnostically important. Morning stiffness related to inflammatory disorders (such as RA or polymyalgia rheumatica) is precipitated by prolonged rest, is described as severe, lasts for hours, and may improve with activity and anti-inflammatory medications. By contrast, intermittent stiffness (also known as gel phenomenon), associated with noninflammatory conditions [such as osteoarthritis (OA)], is precipitated by brief periods of rest, usually lasts <60 min, and is exacerbated by activity. Fatigue may accompany inflammation (as seen in RA and polymyalgia rheumatica) but may also be prominent in fibromyalgia (a noninflammatory disorder), anemia, cardiac failure, endocrinopathy, poor nutrition, poor sleep, or depression. Noninflammatory disorders may be related to trauma (rotator cuff tear), repetitive use (bursitis, tendonitis), degeneration or ineffective repair (OA), neoplasm (pigmented villonodular synovitis), or pain amplification (fibromyalgia). Noninflammatory disorders are often characterized by pain without synovial swelling or warmth, absence of inflammatory or systemic features, daytime gel phenomena rather than morning stiffness, and normal (for age) or negative laboratory investigations.

Identification of the nature of the underlying process and the site of the complaint will enable the examiner to narrow the diagnostic considerations and to assess the need for immediate diagnostic or therapeutic intervention, or for continued observation. Figure 17-1 presents a logical approach to the evaluation of patients with musculoskeletal complaints.

In the formulation of a differential diagnosis, the examiner should be mindful of the most common causes of musculoskeletal complaints (Fig. 17-2). Thus, the prevalence of these disorders in the general population may facilitate an early diagnosis. As trauma, fracture, and fibromyalgia are among the most common causes of presentation, these should be considered during the initial encounter. The frequency of these disorders is best clarified by dividing patients according to their age. Hence, those >60 years are commonly affected by repetitive use/strain disorders, gout (men only), RA, spondyloarthritis, and infectious arthritis. Patients >60 years are frequently affected by OA, crystal (gout and pseudogout) arthritis, polymyalgia rheumatica, osteoporotic fracture, and septic arthritis.

Algorithm for the diagnosis of musculoskeletal complaints. An approach to formulating a differential diagnosis (shown in italics). (ESR, erythrocyte sedimentation rate; CRP C-reactive protein; DIP, distal inter-phalangeal; CMC, carpometacarpal; PIP, proximal interphalangeal; MCP metacarpophalangeal; MTP, metatarsophalangeal; PMR, polymyalgia rheumatica; SLE, systemic lupus erythematosus; JA, juvenile arthritis.)

FIGURE 17-1

Algorithm for the diagnosis of musculoskeletal complaints. An approach to formulating a differential diagnosis (shown in italics). (ESR, erythrocyte sedimentation rate; CRP C-reactive protein; DIP, distal inter-phalangeal; CMC, carpometacarpal; PIP, proximal interphalangeal; MCP metacarpophalangeal; MTP, metatarsophalangeal; PMR, polymyalgia rheumatica; SLE, systemic lupus erythematosus; JA, juvenile arthritis.)

Clinical History

Additional historic features may reveal important clues to the diagnosis. Aspects of the patient profile, complaint chronology, extent of joint involvement, and precipitating factors can provide important information. Certain diagnoses are more frequent in different age groups (Fig. 17-2). SLE and reactive arthritis occur more frequently in the young, whereas fibromyalgia and

RA are frequent in middle age, and OA and polymyalgia rheumatica are more prevalent among the elderly. Diagnostic clustering is also evident when sex and race are considered. Gout and the spondyloarthropathies (e.g., ankylosing spondylitis) are more common in men, whereas RA, fibromyalgia, and lupus are more frequent in women. Racial predilections may be influential. Thus, polymyalgia rheumatica, giant cell arteritis, and Wegener’s granulomatosis commonly affect whites, whereas sarcoidosis and SLE more commonly affect African Americans. Familial aggregation may be seen in disorders such as ankylosing spondylitis, gout, and Heberden’s nodes of OA.

Algorithm for consideration of the most common musculoskeletal conditions. (IBD, inflammatory bowel disease; GC, gonococcal.)

FIGURE 17-2

Algorithm for consideration of the most common musculoskeletal conditions. (IBD, inflammatory bowel disease; GC, gonococcal.)

The chronology of the complaint is an important diagnostic feature and can be divided into onset, evolution, and duration.The onset of disorders such as septic arthritis or gout tends to be abrupt, whereas OA, RA, and fibromyalgia may have more indolent presentations. The patients’ complaints may evolve differently and be classified as chronic (OA), intermittent (crystal or Lyme arthritis), migratory (rheumatic fever, gonococcal or viral arthritis), or additive (RA, psoriatic arthritis). Musculoskeletal disorders are typically classified as acute or chronic based upon a symptom duration that is either less than or greater than 6 weeks, respectively. Acute arthropathies tend to be infectious, crystal induced, or reactive. Chronic conditions include noninflammatory or immunologic arthritides (e.g., OA, RA) and nonar-ticular disorders (e.g.,fibromyalgia).

The extent of articular involvement is often diagnostic. Articular disorders are classified based on the number of joints involved, as either monarticular (one joint), oligoarticular or pauciarticular (two or three joints), or polyarticular (more than three joints). Although crystal and infectious arthritides are often mono- or oligoarticular, OA and RA are polyarticular disorders. Nonarticular disorders may be classified as either focal or widespread. Complaints secondary to tendinitis or carpal tunnel syndrome are typically focal, whereas weakness and myalgia, due to polymyositis or fibromyalgia, are more diffuse in their presentation. Joint involvement in RA tends to be symmetric, whereas the spondyloarthropathies and gout are often asymmetric and oligoarticular. The upper extremities are frequently involved in RA and OA, whereas lower extremity arthritis is characteristic of reactive arthritis and gout at their onset. Involvement of the axial skeleton is common in OA and ankylosing spondylitis but is infrequent in RA, with the notable exception of the cervical spine.

The clinical history should also identify precipitating events, such as trauma, drug administration (Table 17-2), or antecedent or intercurrent illnesses, that may have contributed to the patient’s complaint. Certain comorbidities may predispose to musculoskeletal consequences. This is especially so for diabetes mellitus (carpal tunnel syndrome), renal insufficiency (gout), psoriasis (psoriatic arthritis), myeloma (low back pain), cancer (myositis), and osteoporosis (fracture) or when using certain drugs such as glucocorticoids (osteonecrosis, septic arthritis) and diuretics or chemotherapy (gout).

A thorough rheumatic review of systems may disclose useful diagnostic information. A variety of musculoskeletal disorders may be associated with systemic features such as fever (SLE, infection), rash (SLE, psoriatic arthritis), nail abnormalities (psoriatic or reactive arthritis), myalgias (fibromyalgia, myopathy), or weakness (polymyositis, neuropathy). In addition, some conditions are associated with involvement of other organ systems including the eyes (Behfet’s disease, sarcoidosis, spondyloarthritis), gastrointestinal tract (scleroderma, inflammatory bowel disease), genitourinary tract (reactive arthritis, gonococcemia), or the nervous system (Lyme disease,vasculitis).

TABLE 17-2

DRUG-INDUCED MUSCULOSKELETAL CONDITIONS

Arthralgias

Quinidine, cimetidine, quinolones, chronic acyclovir, interferon, IL-2, nicardipine, vaccines, rifabutin, aromatase and HIV protease inhibitors

Myalgias/myopathy

Glucocorticoids, penicillamine, hydroxychloroquine, AZT, lovastatin, simvastatin, pravastatin, clofibrate, interferon, IL-2, alcohol, cocaine, taxol, docetaxel, colchicine, quinolones, cyclosporine

Tendon rupture

Quinolones, glucocorticoids

Gout

Diuretics, aspirin, cytotoxics, cyclosporine, alcohol, moonshine, ethambutol

Drug-induced lupus

Hydralazine, procainamide, quinidine, phenytoin, carba-mazepine, methyldopa, isoniazid, chlorpromazine, lithium, penicillamine, tetracyclines, TNF inhibitors, ACE inhibitors, ticlopidine

Osteonecrosis

Glucocorticoids, alcohol, radiation, bisphosphonates

Osteopenia

Glucocorticoids, chronic heparin, phenytoin, methotrexate

Scleroderma

Vinyl chloride, bleomycin, pentazocine, organic solvents, carbidopa, tryptophan, rapeseed oil

Vasculitis

Allopurinol, amphetamines, cocaine, thiazides, penicillamine, propylthiouracil, montelukast, TNF inhibitors, hepatitis B vaccine, trimethoprim/sulfamethoxazole

Note: IL-2, interleukin 2; TNF, tumor necrosis factor; ACE, angiotensinconverting enzyme.

Modified Health Assessment Questionnaire

Today are you able to

(check box)

No

difficulty

Some

difficulty

Much

difficulty

Cannot

do

Dress yourself; including laces & buttons?

Get in and out of bed?

Lift a full cup or glass to your mouth?

Walk outdoors on flat ground?

Wash and dry your entire body?

Bend down & pick up clothing from floor?

Turn regular faucets on and off?

Get in and out of a car?

FIGURE 17-3

Modified Health Assessment Questionnaire.

Lastly, the examiner should assess the level of pain and physical limitation that accompanies the complaint. The intensity of the patient’s pain, stiffness, or weakness can be quantified (0-10) verbally or with the use of a 10-cm visual analogue scale (0 = no pain and 10 = the worst possible pain). Functional limitation and disability should be identified and recorded for future comparisons. There are several validated functional measures that are easily incorporated into the musculoskeletal evaluation, such as the modified Health Assessment Questionnaire (Fig. 17-3).

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