Chronic Polyarticular Gout at Unusual Sites: A Rare Case
TJ01-TJ02
Correspondence
Dr. Senthil Kumar Aiyappan,
Professor and Head, Department of Radiodiagnosis, SRM Medical College Hospital and Research Centre, SRMIST, Kattankulathur, Chengalpet-603203, Tamil Nadu, India.
E-mail: asenthilkumarpgi@gmail.com
A 59-year-old male presented to the orthopaedics department with complaints of pain and swelling in the right knee for one week. The pain was insidious in onset with gradual progression, dull aching, non-radiating, and aggravated on weight bearing and knee movements with no relieving factors. The patient also had a similar history of pain and swelling in both knee joints on and off for the past three years. The patient also gave a history of pain in the neck region radiating to both upper limbs for the past two months. The patient was not a known hypertensive, diabetic, not a smoker or alcoholic. The patient consumed a vegetarian diet. The medical history of the patient revealed chronic gout for four years, diagnosed elsewhere and the patient was on intermittent treatment with allopurinol. The general examination of the patient was unremarkable.
On local examination, the right knee showed diffuse swelling and tenderness on the medial aspect of the knee with no evidence of redness or warmth. Blood investigations revealed haemoglobin of 13.2 mg/dL (13-17 mg/dL), elevated blood urea of 49 mg/dL (17-43 mg/dL), uric acid of 9.3 mg/dL (3.5 to 7.2 mg/dL), reduced calcium of 8.1 mg/dL (8.8-10.6 mg/dL) and serum creatinine of 1.2 mg/dL (0.7 to 1.3 mg/dL). X-rays of both knees including both anteroposterior and lateral projections were taken which showed small marginal osteophytes involving medial femoral and tibial condyles on both sides with multiple subchondral cysts involving the lower end of the bilateral femur and upper end of the bilateral tibia. Subtle increased density was noted within the bilateral knee joint. The imaging findings on X-ray suggested chronic gout with associated osteoarthritis (Table/Fig 1)a-d. Computed Tomography (CT) of both knees was taken to confirm the X-ray findings and to demonstrate hyperdense soft-tissue which reaffirmed chronic tophaceous gout. CT showed small marginal osteophytes involving medial femoral, and tibial condyles and multiple large subchondral cysts. Hyperdense soft-tissue was demonstrated within the bilateral knee joint (Table/Fig 2)a-d which was suggestive of chronic tophaceous gout/gouty arthritis. The patient had also given a history of cervical radiculopathy for which an MRI and CT of the cervical spine were done. CT showed evidence of hyperdense soft-tissue along the atlantoaxial joint and bilateral Sternoclavicular Joint (SCJ) - suggestive of chronic gout involving the atlantoaxial joint and bilateral SCJ (Table/Fig 3)a-d. MRI of the right knee joint was done to evaluate synovial thickening and cartilage assessment. MRI showed T2 hypointense areas in the knee joint corresponding to hyperdense soft-tissue on CT predominantly involving Hoffa’s fat pad and suprapatellar bursa with mild synovial thickening. These features were suggestive of chronic gout (Table/Fig 4)a. MRI of the cervical spine showed evidence of cervical spondylosis with hypointense areas in the regions of the atlantoaxial joint corresponding to hyperdense soft-tissue on CT- suggestive of tophaceous gout (Table/Fig 4)b. Synovial fluid analysis of the knee joint was not done since there was no significant joint effusion. The overall laboratory and radiological findings were confirmatory for chronic tophaceous gout involving the bilateral knee joint (Right > Left), sternoclavicular, and atlantoaxial joint. The patient was managed conservatively with allopurinol 100 mg twice a day and discharged as he was not willing for further management.
Gout is a form of inflammatory arthritis characterised by elevated levels of uric acid in the blood, known as hyperuricaemia. This excess uric acid can lead to the formation of urate crystals in joints and surrounding tissues, causing pain (1). Risk factors for developing gout include increasing age, male sex, postmenopausal state, African American race, and certain comorbidities such as insulin resistance, obesity, hypertension, congestive heart failure, and organ transplantation (1). Impaired renal excretion of uric acid is one of the major contributing factors to hyperuricaemia which is defined as a serum uric acid level of more than 7 mg/dL in males and 6 mg/dL in females (2),(3). Gout typically presents as sudden and severe pain, swelling, redness, and tenderness in a single joint, most commonly the big toe (first metatarsophalangeal joint). However, in the present case, it was polyarticular involvement (3). Tophi are collections of Monosodium Urate (MSU) crystals that are deposited in soft-tissues or within the tendons and joints. Typical locations of the tophaceous deposits are the first metatarsophalangeal joint, the Achilles tendon, the olecranon bursa, and the ear and finger pulps (4). In this case, there was the involvement of the bilateral knee joints, atlantoaxial joint, and SCJ. These deposits can also occur in atypical locations which include second metacarpal, patellar tendon, spinal cord, and clavicle (4),(5). Tophi occurring in the SCJ and atlanto-axial joint is an extremely rare condition (6),(7), both of which were involved in the present case. In a case report described by Romero AB et al., there was the involvement of atlantoaxial joint by tophaceous gout in an 82-year-old male who had a 40-year history of proven gout (6). In the present case, the patient is a 59-year-old male with a 4-year history of gout. According to the case report described by Romero AB et al., there were only seven described cases of atlantoaxial joint involvement including his case till 2021(6). To the best of our knowledge after 2021, there were no case reports of gout involving the atlantoaxial joint. Sahdev N et al., described a case of tophaceous gout involving the left SCJ. In that case, the SCJ involvement mimicked a bony tumour (7), however, in this case, there was no swelling and only joint involvement was noted on CT imaging with characteristic high-density soft-tissue deposits. According to the case report described by Sahdev N et al., there were only three reported cases of true gout involving the SCJ including his case till 2021(7). Patients with gout need to manage their condition through lifestyle modifications, such as dietary changes to reduce purine intake (which can contribute to uric acid formation), weight management, and avoiding triggers like alcohol consumption (8). To conclude, this case is unique in the form that tophaeous deposits in the atlantoaxial joint and SCJ are rarely reported in the literature and should be looked for, in cases of chronic gout.