Answer for BIR CoW 29 Jan 2023
Chronic gouty arthritis
Findings
Well-defined “punched-out” erosions with sclerotic margins in a marginal and juxta-articular distribution, with overhanging edges, noted involving right first metatarsophalangeal joint with surrounding soft tissue swelling and calcification adjacent to the joint. Bone density appears normal with absence of periarticular osteopenia.
Discussion
Gout is an inflammatory arthritis due to the deposition of monosodium urate crystals in and around the joints and any joint can be involved in gout, but the first MTP joint is the most common.The crystals are needle-shaped and are negatively birefringent in plane-polarized light . There are five recognized stages of gout: Asymptomatic hyperuricemia ,acute gouty arthritis ,intercritical gout , chronic tophaceous gout and gouty nephropathy . The primary risk factor is hyperuricemia which can be due to underexcretion of uric acid ( 90%) by kidneys like chronic kidney disease,hypertension, hyperparathyroidism ,alcoholism ,drugs and overproduction of uric acid (10%) like myeloproliferative disorders ,hemolysis ,extreme exercise and Lesch-Nyhan syndrome . Imaging features: Classic x-ray findings is the presence of well-defined “punched-out” erosions with sclerotic margins in a marginal and juxta-articular distribution, with overhanging edges, also known as rat bite erosions. Earliest sign is joint effusion with preservation of joint space until late stages of the disease. Bone density is normal with absence of periarticular osteopenia . Tophi is a characteristic radiologic changes ,seen as soft-tissue dense masses adjacent to the joints in chronic stages of the disease which may be hyperdense due to the crystals, and the tophi can calcify . Ultrasound have a diagnostic role in assessing gouty joints. Joint inflammation, synovitis, hypertrophy and bony erosions can be seen on ultrasound scans. Features specific to gout include double contour cartilage line, visualizing urate crystal deposition and tophaceous material . CT : Findings generally reflect those on the plain radiograph.Dual-energy CT can distinguish between urate mineralization and calcification, which may be useful for cases where the clinical and biochemical presentation is atypical . Allowing for not only visualization and characterization, but also quantification of monosodium urate crystal deposits, it can be used for treatment monitoring as well . MRI : Signal characteristics of gouty tophi are usually T1 isointense ,T2 variable but the majority of lesions are characteristically heterogeneously hypointense.Tophus often enhances on contrast. Management: Acutely, gout can be managed with non-steroidal anti-inflammatory drugs , colchicine, prednisolone, or newer cytokine blocking agents (e.g. IL-1 blockers such as anakinra or canakinumab) . In the long-term, xanthine oxidase inhibitors (e.g. Allopurinol or febuxostat), uricosuric drugs (e.g. Probenecid), or uricase agents may be used to reduce urate levels. Tophaceous gout can also be managed with surgical excision of symptomatic lesions
Findings
Well-defined “punched-out” erosions with sclerotic margins in a marginal and juxta-articular distribution, with overhanging edges, noted involving right first metatarsophalangeal joint with surrounding soft tissue swelling and calcification adjacent to the joint. Bone density appears normal with absence of periarticular osteopenia.
Discussion
Gout is an inflammatory arthritis due to the deposition of monosodium urate crystals in and around the joints and any joint can be involved in gout, but the first MTP joint is the most common.The crystals are needle-shaped and are negatively birefringent in plane-polarized light . There are five recognized stages of gout: Asymptomatic hyperuricemia ,acute gouty arthritis ,intercritical gout , chronic tophaceous gout and gouty nephropathy . The primary risk factor is hyperuricemia which can be due to underexcretion of uric acid ( 90%) by kidneys like chronic kidney disease,hypertension, hyperparathyroidism ,alcoholism ,drugs and overproduction of uric acid (10%) like myeloproliferative disorders ,hemolysis ,extreme exercise and Lesch-Nyhan syndrome . Imaging features: Classic x-ray findings is the presence of well-defined “punched-out” erosions with sclerotic margins in a marginal and juxta-articular distribution, with overhanging edges, also known as rat bite erosions. Earliest sign is joint effusion with preservation of joint space until late stages of the disease. Bone density is normal with absence of periarticular osteopenia . Tophi is a characteristic radiologic changes ,seen as soft-tissue dense masses adjacent to the joints in chronic stages of the disease which may be hyperdense due to the crystals, and the tophi can calcify . Ultrasound have a diagnostic role in assessing gouty joints. Joint inflammation, synovitis, hypertrophy and bony erosions can be seen on ultrasound scans. Features specific to gout include double contour cartilage line, visualizing urate crystal deposition and tophaceous material . CT : Findings generally reflect those on the plain radiograph.Dual-energy CT can distinguish between urate mineralization and calcification, which may be useful for cases where the clinical and biochemical presentation is atypical . Allowing for not only visualization and characterization, but also quantification of monosodium urate crystal deposits, it can be used for treatment monitoring as well . MRI : Signal characteristics of gouty tophi are usually T1 isointense ,T2 variable but the majority of lesions are characteristically heterogeneously hypointense.Tophus often enhances on contrast. Management: Acutely, gout can be managed with non-steroidal anti-inflammatory drugs , colchicine, prednisolone, or newer cytokine blocking agents (e.g. IL-1 blockers such as anakinra or canakinumab) . In the long-term, xanthine oxidase inhibitors (e.g. Allopurinol or febuxostat), uricosuric drugs (e.g. Probenecid), or uricase agents may be used to reduce urate levels. Tophaceous gout can also be managed with surgical excision of symptomatic lesions
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!