From the Guidelines
For a patient with joint pain who hunts, cleans, and eats his own game, I recommend a comprehensive lab panel including rheumatoid factor, anti-CCP antibodies, ESR, CRP, complete blood count, comprehensive metabolic panel, uric acid level, and importantly, testing for zoonotic infections such as Lyme disease (Borrelia burgdorferi antibodies), Brucellosis, and Leptospirosis. These tests are crucial because hunters have increased exposure to tick-borne and animal-transmitted diseases that can cause joint pain, as suggested by the need to consider autoimmune blood panels and inflammatory markers in patients with persistent symptoms 1. The diagnostic work-up should include a complete rheumatologic history and examination of all peripheral joints for tenderness, swelling, and range of motion, as well as examination of the spine 1. Key considerations in the diagnostic workup include:
- Complete history and examination as above; laboratory tests as above
- Consider plain x-ray/imaging to exclude metastases and evaluate joint damage (erosions), if appropriate
- Consider autoimmune blood panel, including ANA, rheumatoid factor (RF), and anti–citrullinated protein antibody (anti-CCP), and inflammatory markers (ESR and CRP) if symptoms persist
- Consider HLA B27 testing if symptoms are suggestive of reactive arthritis or affect the spine
- Consider early referral to a rheumatologist if there is joint swelling (synovitis) or if symptoms of arthralgia persist > 4 weeks 1. Additionally, testing for Lyme disease is particularly important in endemic areas, where it can be a common cause of facial paralysis and other symptoms, and can be diagnosed using a 2-step process involving ELISA and Western blot 1. Overall, a comprehensive approach to diagnosis is necessary to identify the underlying cause of joint pain in this patient population.
From the Research
Lab Tests for Joint Pain
The patient's joint pain, combined with their activities of hunting, cleaning, and eating game, may suggest several potential causes.
- Osteoarthritis (OA) is a common joint disease that could be a possible cause of joint pain, as it affects an estimated more than 240 million people worldwide 2.
- Tick-borne infections such as Lyme disease, human granulocytic anaplasmosis (HGA), and babesiosis are also potential causes, given the patient's outdoor activities 3.
- Inflammatory and degenerative diseases of joints are major causes of chronic pain, and joint pain can be caused by mechanical hyperalgesia, which is the major pain problem in both inflammatory and degenerative joint diseases 4.
Diagnostic Tests
To diagnose the cause of joint pain, several lab tests can be performed:
- For OA, radiographic indicators such as marginal osteophytes and joint space narrowing can be used for diagnosis 2.
- For tick-borne infections, US Food and Drug Administration-approved serologic tests such as enzyme immunoassay (EIA) and Western blot testing can be used to diagnose Lyme disease, while microscopy and polymerase chain reaction assay of blood specimens can be used to diagnose HGA and babesiosis 3.
- For chronic musculoskeletal pain, a comprehensive assessment of the patient's pain and functional limitations is necessary, and treatment should address the patient's pain, education, empowerment, and support to enable patients to set and achieve meaningful functional goals 5, 6.
Treatment
Treatment for joint pain will depend on the underlying cause:
- For OA, exercises, weight loss, and education, complemented by topical or oral nonsteroidal anti-inflammatory drugs (NSAIDs) and intra-articular steroid injections, can be effective 2.
- For tick-borne infections, oral doxycycline, amoxicillin, and cefuroxime axetil can be used to treat Lyme disease, while a 10-day course of oral doxycycline is effective for HGA and a 7- to 10-day course of azithromycin plus atovaquone is effective for mild babesiosis 3.
- For chronic musculoskeletal pain, a multidisciplinary approach that addresses the patient's pain, education, empowerment, and support is necessary to improve patient outcomes 5, 6.