Reactive arthritis: Clinical sciences

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Introduction0:00–0:48

Reactive arthritis, formally known as Reiter syndrome, belongs to a group of conditions called seronegative spondyloarthropathies.
Seronegative means that the autoantibody called rheumatoid factor or RF is absent. Reactive arthritis is associated with autoimmune inflammation of joints that usually develops after genitourinary infections, most commonly chlamydia and gonorrhea; or intestinal infections, usually salmonella or shigella.
Keep in mind that in most cases, this inciting infection is asymptomatic! Okay, if your patient presents with chief concerns suggesting reactive arthritis, first, you should perform a focused history and physical.

History and Physical0:48–3:39

Reactive arthritis doesn't just affect the joints, so don’t let the name fool you! Your patient will typically report pain in the large joints of the lower extremities, including knees, ankles, and feet.
Keep in mind that the pain is usually asymmetric! Additionally, they will report systemic symptoms like fatigue, malaise, and low-grade fever; with possible ocular symptoms, such as burning of the eyes.
Additionally, this condition can affect almost any genitourinary structure, including the urethra, bladder, cervix, and prostate.
They might also report recent genitourinary symptoms, like dysuria and urethral discharge; or gastrointestinal symptoms, such as diarrhea.
Typically, symptoms of reactive arthritis occur several days to weeks after the inciting infection. Additionally, the physical examination may reveal a tender lower extremity joint with effusion; and tenderness in the sacroiliac joint.
You may also observe several extra-articular manifestations, such as enthesitis, or inflammation of the attachment sites of tendons to bones; as well as dactylitis, also known as sausage fingers.
Look out for common dermatologic findings, like nail pitting and onycholysis, where the nail separates from the nail bed.
You may also notice keratoderma blennorrhagicum, which causes psoriatic nodules on the palms and soles; or oral ulcers. They may also present with other ophthalmologic findings, including simple conjunctivitis as well as anterior uveitis, which involves inflammation of the front eye chamber with the iris and ciliary body.
In rare cases, your patient may have cardiac involvement with conduction disturbances and valvular dysfunction. Now, here’s a high-yield fact!
To help recall the classic triad of conjunctivitis, urethritis, and arthritis commonly observed in reactive arthritis, remember the phrase CAN’T SEE, CAN’T PEE, and CAN’T CLIMB A TREE!
Note that this triad is only present in about one third of cases, so be on the lookout for other manifestations too! With these findings, you should suspect inflammatory or infectious arthritis.

Suspect inflammatory/infectious arthritis3:39–5:16

Your next step is to obtain labs, such as CBC, inflammatory markers, like ESR and CRP, rheumatoid factor, ANA, and HLA-B27.
Additionally, you might want to order an X-ray of the affected joints. Laboratory results will typically show a CBC with leukocytosis and anemia.
You will also see marked elevation of ESR and CRP, as well as a negative ANA and rheumatoid factor. Finally, some individuals might present with positive HLA-B27.
If you did order imaging, X-rays of affected joints may reveal linear or fluffy periostitis of the distal tibia or fibula, as well as calcaneal enthesitis and spurring.
At this point, you should suspect reactive arthritis.Now, here’s a clinical pearl to keep in mind! The laboratory workup for reactive arthritis can be quite extensive.
You may need additional labs, such as HIV, parvovirus B19, and hepatitis B and C. These tests can help you rule out other conditions because they are typically negative in individuals with reactive arthritis.
Okay, once you suspect reactive arthritis, your next step should be to assess for evidence of previous infection. Order nucleic acid amplification tests, or NAATs, for Gonorrhea and Chlamydia, as well as stool cultures to rule out Shigella, Campylobacter, and Salmonella.

Diagnosis5:16–6:08

Also, don’t forget to aspirate synovial fluid and send it for culture. Now, if the NAAT results and stool cultures are negative, but the synovial fluid culture is positive, consider an alternative diagnosis, like septic arthritis.
On the other hand, if the NAAT results are positive or the stool culture is positive, and the synovial fluid culture is negative, diagnose reactive arthritis!
Your next step is to initiate medical therapy by treating the underlying infection. For example, if your patient is positive for gonorrhea or chlamydia, treat with an appropriate antibiotic.

Treatment6:08–8:40

For symptoms of arthritis, give nonsteroidal anti-inflammatory drugs, or NSAIDs. Finally, if your patient has conjunctivitis or uveitis, start a topical steroid.Here’s a clinical pearl to keep in mind!
Antibiotics don't benefit an enteric source of infection, but can help with genitourinary infections caused by Chlamydia.
With Chlamydial infections, early initiation of combination antibiotics during the active phase of infection, like doxycycline plus rifampicin, or azithromycin plus rifampicin, can prevent progression to reactive arthritis.
Still, even when introduced later in the disease process, combination antibiotics can shorten the time frame of active symptoms.Alright, once you initiate the therapy, wait 2 to 4 weeks and assess the patient’s response to treatment.
If symptoms resolve, wean off medical therapy. On the flip side, if symptoms persist or worsen, consider intra-articular glucocorticoid injections or even systemic glucocorticoids, if multiple joints are affected.
In cases where arthritis persists for 6 months or more, start treatment with a disease-modifying antirheumatic agent or DMARD, such as methotrexate or sulfasalazine, and if joint manifestations still persist, consider starting a tumor necrosis factor inhibitor, or TNFI, such as Etanercept.
Finally, if needed, don’t forget to consult your rheumatology and ophthalmology teams! Here’s a final clinical pearl to keep in mind!
While most cases of reactive arthritis are self-limiting, you should schedule periodic follow-ups to ensure your patient’s condition is improving.
Long-term complications include recurrent arthritis, chronic arthritis or sacroiliitis, urethral strictures, cataracts, and even aortic root necrosis.
This is especially common in patients who are HLA-B27 positive. All right, as a quick recap… Reactive arthritis is an autoimmune inflammation of joints that usually occurs after genitourinary or gastrointestinal infections.

Review8:40–9:29

The typical presentation includes a classic triad of joint, ocular, and urinary involvement. The diagnosis is based on laboratory studies, primarily gonococcal and chlamydial NAATs, as well as stool and synovial fluid cultures.
Once you confirm the diagnosis, treat the underlying infection, manage arthritis with NSAIDs, and if there’s ocular involvement, give topical steroids.
If your patient fails to improve, consider intra-articular or systemic steroids, as well as DMARDs and