Joint Pain

Joint Pain By Dr. Ahmad Shaheen

The differential diagnosis of joint pain Narrowing the differential diagnosis When evaluating the patient with joint pain, you may consider six key concepts during the history and physical examination that may help to narrow the differential diagnosis.

The six key concepts are: ØIs the joint pain really an arthritis? ØIs the condition acute or chronic? ØIs the problem inflammatory or noninflammatory? ØWhat is the pattern of joint involvement? ØAre there associated systemic features? ØWhat are the demographics of the patient that might make one diagnosis more tenable?

The differential diagnosis of joint pain Articular, periarticular, or nonarticular? There are a variety of structures that can become painful and might be interpreted as an arthritis by patients. Causes of joint pain from outside the joint (structures outside the joint capsule) can be from periarticular structures. The following is a list of structures around a joint that might present to you as joint pain.

Periarticular causes of joint pain ØBursitis ØFaciitis ØTendonitis ØLigament Injury ØEpicondylitis ØMyofacial Pain/Fibromyalgia

The differential diagnosis of joint pain There are also a variety of nonarticular abnormalities affecting bone, nerve, or blood vessels that may present as joint pain. Below is a list of such causes.

Nonarticular causes of joint pain ØTumors of Bone ØRadiculopathy ØOsteomyelitis ØNeuroma ØNerve Entrapment ØVasculopathy

The differential diagnosis of joint pain Differentiation of these problems from an arthritis requires careful physical examination which should include: ØInspection of the joint area for evidence of swelling or redness ØPassive range of motion of the joint(s) in the area noting pain, reduction of motion, or instability ØActive range of motion of the joint(s) in the area noting pain that was not there when the joint(s) were passively moved ØResisted range of motion of the joint(s) in the area again noting pain ØPalpation of the joint line(s) and surrounding structures noting tenderness, joint effusion(s), and boney changes. ØMost soft tissue problems do not hurt with passive motion while most forms of arthritis do. ØTendonitis is typically painful with active or resisted motion. ØA bursitis is usually painful only with palpation.

The differential diagnosis of joint pain Acute vs. chronic Acute refers to conditions lasting less than 8 weeks while chronic signifies conditions that persist for a longer period of time. Acute also suggests a rapid onset. Many acute disorders are also self-limited. This division of acute and chronic can help focus the evaluation especially for conditions that have been present for more than 8 weeks.

Inflammatory vs. noninflammatory This is a very helpful point in limiting your differential diagnosis. Inflammatory disorders usually present with morning stiffness that lasts longer than 30-40 minutes, stiffness that increases with rest, relief of symptoms with exercise, some degree of swelling, and a synovial fluid WBC that is above 2000/mm3. Most of the 2000 cells should also

The differential diagnosis of joint pain Inflammatory vs. noninflammatory (cont.) Noninflammatory disorders usually present with only limited morning stiffness (< 15 minutes), pain with use, relief of pain with rest, swelling may or may not be present, and synovial fluid WBC is typically less than 2000/mm3. An initial determination of the character of the synovial fluid at the bed side can be made by looking at the fluid in a glass tube against newsprint. The print can still be read through noninflammatory fluid while inflammatory fluid will obscure the print. The intensity of the synovial inflammation is only relatively helpful in the differential diagnosis. Below is a chart of synovial fluid differentiated by cell count. An important point to remember is that an infected joint may not have septic range WBC. If you at all suspect infection send the fluid for gram stain and culture

The differential diagnosis of joint pain Synovial fluid analysis

Fibromyalgia typically presents with marked AM stiffness, pain with use and pain and stiffness at night so that it is not clearly inflammatory or noninflammatory

Pattern recognition and the differential diagnosis 3 different classes Rheumatologists spend a good deal of their training learning to recognize various forms of arthritis by their pattern of joint involvement. They divide the conditions into monoarticular (one joint only), pauciarticular (2-5 joints), and polyarticular (more than 6 joints).. The following lists are not all inclusive. They include the most common entities someone in the primary care setting would encounter. The purpose of this differentiation is to focus the initial evaluation and help the "splitters" among us.

Pattern recognition and the differential diagnosis Monoarticular arthritis Causes of monoarthritis

Monoarticular Arthritis Nongonococcal septic arthritis is the most serious cause of monoarthritis. The presentation is that of an acute or subacute onset of mono- or rarely pauciarthritis. Large joints are usually affected especially knees. Patients most often look systemically ill and will have fever, chills, and will have an elevated WBC and ESR. Patients with underlying arthritis especially rheumatoid arthritis are at increased risk of septic arthritis and may not have the usual symptoms due to antiinflammatory medications. The most common organisms are Staphylococcus aureus, Streptococcus sp. and much less common are gram negatives but think of the latter in the immunosuppressed or in IV drug users. The initial evaluation should include arthrocentesis for gram stain and culture and WBC, blood cultures, as well as an ESR. The patient should be admitted and IV antibiotics started while

Monoarticular Arthritis Gonococcal arthritis is seen in sexually active young adults and only 25% have local genitourinary symptoms. Patients are usually systemically ill and have dermatitis, tenosynovitis, and migratory arthritis. Blood cultures are positive in only 5%, GU cultures in 80%, and synovial fluid cultures in 30%. Luckily, most strains that cause gonococcal arthritis are penicillin sensitive although , resistant strains are emerging. Initial evaluation should include the above cultures plus consideration of pharyngeal and rectal cultures. Patients often need a few days of hospitalization then can be treated as an outpatient.

Monoarticular Arthritis Endocarditis causes musculoskeletal symptoms in up to 40% of affected patients. Inflammatory low back pain is common as is mono- or pauciarthritis. It is interesting to note that the fluid while inflammatory is usually sterile. This is thought to be due to immune complex deposition in the synovium. Look for peripheral signs of immune complex deposition such as cutaneous vasculitis, painful nodules, listen for a murmur, check an ESR, blood cultures, CBC, cultures of synovial fluid, and if endocarditis is likely, admit the patient and begin antibiotics. Of note, rheumatoid factor is frequently positive in these

Monoarticular Arthritis Crystals causing arthritis include urate, calcium pyrophosphate, and appatite. Urate gout is probably the most common cause of acute inflammatory monoarthritis. Inflammation is usually intense and the patient will relate a history of previous self-limited attacks. First MTP is a common site for urate gout and knee for calcium pyrophosphate. Young women can have so called hydroxyappatite pseudopodagra affecting the 1st MTP. Patients can have a pauciarticular presentation with urate and pyrophosphate. For urate gout, a history of ETOH use, history of kidney stones, or a family history of urate gout is helpful. There are some distinctive X-ray findings for calcium pyrophosphate and appatite arthritis (chondrocalcinosis and fluffy calcification respectively) On examination, look for tophi and synovial fluid analysis is very helpful in the definitive diagnosis of all but hydroxyappatite. A useful hint to remember is that bugs, blood, and crystals

Monoarticular Arthritis Palindromic rheumatism is an episodic condition usually affecting one joint at a time. The attacks can be fairly intense and the fluid can be quite inflammatory. Attacks usually last several days and resolve. With time, many individuals progress on to frank rheumatoid arthritis. TB and fungi are relatively rare but any chronic monoarthritis without a diagnosis should be considered for synovial biopsy and granulomatous synovitis considered. Osteoarthritis is probably the overall most common cause of monoarthritis and trauma/internal derangement of the knee is not far behind. Meniscal tears can cause chronic noninflammatory type pain and may give symptoms of knee locking or giveway. Avascular necrosis is caused by trauma, alcohol abuse, steroid use, divers, and in patients with hemaglobinopathies. Pain is initially out of proportion to X-rays. Hips, knees and shoulders are usually involved. Early diagnosis is by MRI scan. Synovial neoplasm to remember and is pigmented

Pattern recognition and the differential diagnosis Pauciarticular arthritis Causes of pauciarthritis

Pauciarticular Arthritis Rheumatic fever - In many of these conditions systemic features play an important role in the differential diagnosis. Rheumatic fever is certainly one of these although most adults with rheumatic fever present with only arthritis. The pain is usually out of proportion to the swelling and the symptoms tend to be migratory. Other Jones criteria include carditis, erythema marginatum, chorea, and subcutaneous nodules. Be sure to listen for a murmur and check ASO/streptozyme. The ASO should be followed serially and remember that a positive test still does not prove rheumatic fever. Throat cultures are usually negative by the time rheumatic fever occurs. One often spends time ruling out other diseases even with a suspicion for rheumatic fever due to the lack of definitive diagnostic testing. The presence of carditis though,

Pauciarticular Arthritis Lyme arthritis is a late manifestation of lyme disease and usually presents with recurrent attacks of mono- or pauciarthritis especially including the knee. In this condition, the swelling is often out of proportion to the pain!. A history of exposure and the characteristic rash of Lyme disease are important. By time the arthritis is present, the vast majority of patients have a positive Lyme antibody test. One may have to treat presumptively for at least one course of antibiotics in some marginal cases. Spondyloarthropathies are characterized by their association with the HLA-B27 gene (except the peripheral arthritis of psoriatic arthritis). Features of these illness that are helpful in the diagnosis include inflammatory low back pain, history of inflammatory eye disease (uveitis, iritis, conjunctivitis), urethritis, cervicitis, diarrhea, a variety of hyperkeratotic rashes, and diffuse swelling of digits called sausage digits. Joints most often affected are the large joints of the lower extremities. the most common cause of inflammatory pauciarthritis is a spondyloarthropathy,

Pauciarticular Arthritis Sarcoidosis frequently presents with pauciarthritis. One typical presentation is called Lofgren syndrome and consists of erythema nodosum, hilar adenopathy, and pauciarthritis usually affecting the large joints of the lower extremities. A chronic destructive form also exists and is often seen along with extensive bone cysts on X-ray. Other important features include uveitis and skin lesions. Polymyalgia rheumatica will be discussed below.

Pattern recognition and the differential diagnosis Polyarticular Causes of arthritis polyarthritis

Polyarticular Arthritis Viruses are a common cause of acute self limited arthritis. The ones to remember include hepatitis B, parvovirus B19, and rubella. HIV can cause a variety of rheumatologic syndromes but polyarthritis is unusual. Viral arthridities are usually symmetrical and cause more pain than swelling. They usually are self limited and are associated with rash. The prodrome of hepatitis B can be polyarthritis even before liver function tests are abnormal. Be sure to check for hepatitis B surface antigen. The arthritis usually goes away by the time the patient has clinical hepatitis. Hepatitis C is being recognized as a common infection. It can cause a symmetric polyarthritis that is often accompanied by a positive rheumatoid factor thus being confused with rheumatoid arthritis. There are no nodules with

Polyarticular Arthritis Rheumatoid arthritis is a relatively common disease affecting 1-2% of the US population. Remember that rheumatoid factor is seen in only 70% of patients and may not appear for 1 year. RA is a symmetric arthritis and almost always affects the small joints of the hands and feet. Diagnosis of systemic lupus erythematosus is aided greatly by the ANA testing. A negative ANA plus a negative antiSSA antibody rules out SLE! On the other hand, a positive ANA does not mean SLE! One has to look for other features to go along with the positive ANA not just fatigue and arthralgias. I usually am not impressed with an ANA of less than 1:160 and look for the presence of other autoantibodies as well as objective evidence of inflammation on laboratory testing and examination. Urgent cases of SLE include those

Polyarticular Arthritis Secondary causes of osteoarthrits especially metabolic causes, a symmetric pattern but in places atypical for primary OA. These include the shoulders, elbows, wrists, and MCP joints. The most important cause is idiopathic calcium pyrophosphate disease and less common, but with more significant implications, is hemachromatosis. check a calcium, FE, TIBC, and TSH in a patient with what may be a secondary cause of OA without other explanation (old RA) and or significant chondrocalcinosis on X-ray. Serum sicknesses Symptoms include rash often uriticarial, and inflammatory arthritis affecting large joints. Fever is common and laboratory abnormalities include mild hypocompletemia and normal eosinophil count. The process is self limited resolving in 1-3 weeks after exposure. Typical causes of serum sickness-like reactions are antibiotics especially penicillins

Systemic features and differential diagnosis Systems and related diseases/syndromes There are a variety of systemic features that can help in the differential diagnosis of joint pain/arthritis. Finding these requires a complete review of systems and a good general examination with emphasis on the skin, eyes, heart, lungs, GI, GU, and nervous system. Below is a list of some of the diseases/syndromes for which systemic features are important in the differential diagnosis. Skin ØGout ØSpondyloarthropathy ØSarcoidosis ØLyme disease ØDisseminated gonorrhea ØRheumatic fever ØViral syndromes ØRheumatoid arthritis ØSystemic lupus ØSerum sickness

Systemic features and differential diagnosis Eyes ØSpondyloarthropath y ØSarcoidosis ØRheumatoid arthritis Heart ØSpondyloarthropath y ØLyme disease ØEndocarditis ØSystemic lupus ØRheumatic fever ØRheumatoid arthritis Lungs ØTuberculosis ØFungi

GI/GU ØSpondyloarthropathy ØSystemic lupus ØGout ØEndocarditis CNS/PNS ØSarcoidosis ØLyme disease ØSystemic lupus

Patient demographic and differential diagnosis Demographics and related conditions There are features of the history that can help you focus the differential diagnosis. Knowing which diseases are more common in certain patient groups may move certain conditions to the top of your list. Below is listed some items worthy of note. Age Gender Younger Men Spondyloarthropat Gout hy Spondyloarthropath Disseminated y gonorrhea Women Older Rheumatoid Polymyalgia arthritis rheumatica Gout Osteoathritis

Patient demographic and differential diagnosis Race Africans Sarcoidosis Systemic lupus Europeans Polymyalgia rheumatica Lifestyle Bacteria Gout (ETOH overuse) Endocarditis (IDU) Disseminated gonorrhea Lyme disease (outdoors) Avascular necrosis (ETOH overuse) Other illness Bacteria: immunosuppression, rheumatoid arthritis Gout: renal disease, medications, obesity Tuberculosis & fungi: immunosuppresion Avascular necrosis: steroid use