Case 1: Diagnosis & Conclusions

Case Published: May, 2021

Author: Stacy Bagrova, MD

Editor: Lisa Criscione-Schreiber, MD

Case 1 Index

Final diagnosis: Polyarticular gout

Case outcome: Patient was started on steroids due to severity of inflammation, number of joints involved, and the degree of physical dysfunction as a result of his gout flare.  He was also started on allopurinol. After several days in the hospital, his joint swelling and pain improved, fevers resolved, and WBC trended down to normal. He was discharged home on a prednisone taper and with close follow-up.

Case Summary:

Great job! Let’s dissect this case. The patient is presenting with acute joint swelling, redness, and pain in multiple joints in an asymmetric pattern; in other words, he has asymmetric polyarthritis. Referring to our joint pain schema, the differential diagnosis includes infectious, crystalline, and seronegative arthropathies as most likely diagnoses. RA is also a possibility, although somewhat less likely given asymmetry, acuity, and no small joints involved. Our history and physical exam help us arrange the DDx further: he has no preceding URI or GI illness and no risk factors for STDs, which puts reactive arthritis lower on the list. He lacks symptoms of IBD as well, although his age fits in the second incidence peak. He does not use intravenous drugs, has no clear primary infectious source or recent joint surgery as risk factors for polyarticular septic arthritis, but it needs to be ruled out, nonetheless. These considerations bring crystalline arthropathies to the top of the DDx. In terms of his labs, we confirm that he is significantly inflamed (elevated WBC, platelets, inflammatory makers). The next step is arthrocentesis. Joint fluid analysis shows 46,000 WBC, negative gram stain, no growth on culture, and intracellular MSU crystals, consistent with gout.

Gout is a disease affecting 4% of adults in the US [1]. Alcohol consumption, metabolic syndrome, CKD, diabetes, disease with increased cell turn-over (malignancies, inflammatory states), and transplant are risk factors for the development of gout [1]. Disease manifestations range from single joint involvement (classically – 1st MTP joint, also known as podagra) to polyarticular illness with systemic symptoms and signs of inflammation [2],[3]. Tophi, or chalk-like subcutaneous nodules, can also be seen in MTP, Achilles tendon, helix of ear, olecranon bursa, finger pads, etc., since crystals precipitate at lower body temperature [3].

The diagnosis is made by identifying negatively birefringent needle-shaped crystals on arthrocentesis. If a patient has a history of gout and is presenting with their typical flare, aspiration is always not necessary. However, a newly inflamed joint should be aspirated to rule out septic arthritis and help establish or confirm a diagnosis. Of note, uric acid levels are not diagnostic during an acute flare but are very useful for adjustment of urate-lowering therapy. Imaging, such as plain films or joint ultrasound, may also be helpful in confirming the diagnosis [3].

Acute gout flares are treated with NSAIDs, or colchicine, or intra-articular (if only 1-2 joints are involved) or systemic steroids, or if, NSAIDs and steroids are contraindicated, – anakinra (IL-1 receptor antagonist) [4], [5]. 2020 ACR guidelines also recommend urate-lowering therapy (ULT) for patients who have had ≥ 2 flares in 1 year, have tophi on exam or imaging, or have radiographic evidence of gout-related joint damage [4]. Furthermore, patients with their first flare should be initiated on ULT if they have CKD Stage 3 or worse, serum uric acid (UA) level > 9 mg/dL, or a history of urolithiasis. The risk of a second flare is about 60%. Examples of ULT include allopurinol (first-line), febuxostat, probenecid, and pegloticase. The goal of treatment is to decrease UA to below its solubility threshold of 6.8 mg/dL (a goal of < 6 is used clinically) [4]. Contrary to the popular belief, ULT should be started at the time of acute flare treatment, if ULT is indicated. Flare prophylaxis must be continued while titrating ULT to a goal uric acid level to avoid precipitating a flare [4]

Case 1 Index
Case 1 Introduction
Case 1: Review of Systems
Case 1 Physical Exam
Case 1 Diagnostic Testing
Case 1 Additional Diagnostic Testing