AssessmentsJoint pain: Clinical practice
USMLE® Step 2 style questions USMLE
A 68-year-old woman comes to her primary care physician for evaluation of left knee pain. The symptoms began about half-a-year ago. She works as a supermarket cashier and reports that the pain is worse in the evening. Past medical history is notable for hypertension and atherosclerosis. Temperature is 37.2°C (99.0°F), blood pressure is 137/85 mmHg, and body mass index is 30 kg/m2. Physical examination is notable for crepitus and reduced range of motion in the left knee. No erythema or warmth is noted at the affected joint. Cardiac, pulmonary, and abdominal examinations are noncontributory. Which of the following is the next best step in the management of this patient?
Content Reviewers:Rishi Desai, MD, MPH
Contributors:Antonella Melani, MD
Joint pain is associated with a variety of disorders, so identifying the underlying cause can be hard.
First off, there’s the pain itself and there’s the underlying condition.
The underlying condition causing the joint pain which can either be acute or chronic.
In acute conditions, like a trauma, the joint pain develops right away, whereas in an infection or a bone or soft tissue malignancy the joint pain develop over days to weeks.
Alternatively, in chronic conditions like osteoarthritis, the joint pain happens over weeks to months, and in inflammatory conditions, that typically cause intermittent flares of joint pain, which are acute attacks, but the cause is still chronic.
The first step is to see how many joints are involved.
Generally speaking, joint pain can be monoarticular, meaning only one joint is involved, or polyarticular, meaning two or more joints are involved.
The major causes of monoarticular joint pain are trauma, infection, malignancy, and osteoarthritis.
Now, in the early stages and during flares, some inflammatory diseases can cause monoarticular pain.
So the next step is to figure out if the joint pain is inflammatory or non-inflammatory.
In non-inflammatory disease, the joint pain tends to be acute, worsen with movement and is relieved by rest.
On the other hand, in inflammatory diseases, symptoms tend to be more chronic, and worsen with immobility, leading to morning stiffness.
In addition, with inflammatory conditions, there’s usually swelling, loss of function, redness, and warmth.
Additionally, inflammatory conditions may cause an effusion or synovitis.
In contrast, in non-inflammatory conditions, there might be swelling and loss of function, but there’s usually no redness or warmth.
Finally, inflammatory diseases can cause a wide variety of extra-articular symptoms like fever, fatigue, skin rash, adenopathy, alopecia, oral and nasal ulcers, pleuritic chest pain, Raynaud phenomenon, or dry eyes and mouth.
If an inflammatory condition is suspected, then lab work can help confirm the diagnosis.
A complete blood count might show an increased white blood cell count, an elevated ESR and CRP, and specific antibodies might be elevated, for example, an ANA anti- double stranded DNA antibodies for lupus, rheumatoid factor and anti-citrullinated peptide antibodies for rheumatoid arthritis, anti- Ro and La antibodies for Sjogren’s syndrome, anti-centromere antibodies for scleroderma, and anti-topoisomerase antibodies for systemic sclerosis.