Differential diagnosis of pseudogout of the lumbar spine.

This case report details a rare instance of calcium pyrophosphate dihydrate crystal deposition disease (CPPD), commonly known as pseudogout, affecting the lumbar spine. A man in his mid-50s of age presented with severe low-back pain and fever, initially suspected as a spinal infection. Elevated erythrocyte sedimentation rate and leucocytosis were observed, while the initial imaging showed only lumbar spondylosis with arthritic changes in the right L4-L5 facet joint. However, an MRI revealed a cystic lesion at the right L5-S1 facet joint without signs of spondylodiscitis. Ultrasound-guided needle aspiration and synovial fluid analysis, including polarised light microscopy, identified calcium pyrophosphate crystals. Treatment with intravenous pain management was initially ineffective. Confirmation of CPPD led to successful treatment with oral colchicine, resulting in rapid pain alleviation and fever reduction. The patient reported significant improvement at a 2-week follow-up. This case emphasises the importance of thorough investigation in differentiating common symptoms and avoiding unnecessary treatments, highlighting the role of histological examination in diagnosing rare conditions like spinal CPPD.

Calcium Pyrophosphate Crystal Formation and Deposition: Where Do we Stand and What Does the Future hold?

PURPOSE OF THE REVIEW: Although calcium pyrophosphate deposition (CPPD) has been known since the 1960s, our understanding of its pathogenesis remains rudimentary. This review aims to illustrate the known mechanisms underlying calcium pyrophosphate (CPP) crystal formation and deposition and explore future directions in research. By examining various perspectives, from basic research to clinical and imaging assessments, as well as new emerging methodologies, we can establish a starting point for a deeper understanding of CPPD pathogenesis. RECENT FINDINGS: Recent years have seen significant advances in CPPD research, particularly in the clinical field with the development of the 2023 ACR/EULAR classification criteria for CPPD disease, and in imaging with the introduction of the OMERACT ultrasonographic definitions and scoring system. However, progress in basic research has been slower. New laboratory approaches, such as Raman spectroscopy and omics sciences, offer promising insights that may help piece together the puzzle of CPPD. CPPD is a common yet understudied condition. As the population ages and CPPD becomes more prevalent, there is an urgent need to better understand the disease and the mechanisms involved in crystal formation and deposition, in order to improve diagnosis and therapeutic approaches.

Acute Neck Pain from Crowned Dens Syndrome: A Case Report and Clinical Insights.

BACKGROUND Crowned dens syndrome (CDS) is a rare condition characterized by deposition of calcium pyrophosphate crystals on the odontoid process of the second cervical vertebra, forming a calcified 'crown', with neck pain being a common symptom. The disorder exhibits unique clinical and radiological features, resembling manifestations of meningitis, such as acute headaches and cervical stiffness. There are few case reports and case series related to CDS. Patients generally respond well to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), although there is a certain rate of recurrence. Since there are few reports of CDS, we sought to publish this case report, aiming of increasing clinicians' awareness and reducing misdiagnosis rates. CASE REPORT A 62-year-old man presented to the Emergency Department with "cutting-like" headaches and neck pain for 2 days, and was subsequently diagnosed with CDS by cervical computed tomography (CT) scan, and hematological tests revealed inflammatory manifestations. He was advised to take oral nonsteroidal anti-inflammatory drugs and to rest; his symptoms improved after 3 days and his neck pain had almost resolved after 2 months. CONCLUSIONS In older patients experiencing new headaches and neck pain, along with increased inflammatory markers, particularly those with a history of pseudogout, the possibility of CDS should be considered. Case reports suggest that oral NSAIDs and short courses of corticosteroids can generally alleviate symptoms. Further research is needed on CDS diagnosis and treatment.

Crowned Dens Syndrome-Pseudogout of the Neck.

This is a case report of a patient who presented with neck pain and intermittent pyrexia as a manifestation of pseudogout of the neck.

Diastolic Dysfunction of the Left and Right Ventricles in Patients with Calcium Pyrophosphate Crystal Storage Disease and Osteoarthritis.

The frequency and risk factors for the development of diastolic dysfunction (DD) in patients with CPPD and OA have not been studied. The objective of this study was to determine the frequency and identify risk factors (RF) for the development of DD of the left and right ventricles (LV and RV) in patients with calcium pyrophosphate crystal deposition disease (CPPD) and osteoarthritis (OA). The study included 26 patients with CPPD and with knee OA 18-65 years old, matched in age and gender, without cardiovascular disease (CVD), type 2 diabetes mellitus (DM2), and rheumatic diseases. Conventional risk factors (TRF) of CVD were assessed, and echocardiography was performed. The frequency of DD in patients with CPPD and OA was quite high and almost did not differ in both groups: it was detected in 19 patients, of which 11 (42%) had CPPD and 8 (31%) had OA (p = 0.39). Type 1 LV DD was detected in 10 (39%) patients with CPPD and in 8 (31%) with OA (p = 0.11); type 1RV DD was detected in 8 (31%) patients with CPPD and in 7 (27%) patients with OA (p = 0.17); and type 1 LV DD and RV DD was detected in 7 (27%) patients with both CPPD and with OA. DD types 2 and 3 were not detected in both groups. There were no differences in both groups in CV risk factors, except for the level of CRP (it was higher in CPPD) (p = 0.03). In the CPPD group, mean values of LV E/E' (p = 0.02), LVDT (p = 0.03), LVMI (p = 0.04) were significantly higher than in patients with OA. On the contrary, in patients with OA, indices EDV (p = 0.004) and TVC (p = 0.02) were higher. There were direct correlations between diastolic function indices and the following factors in CPPD: LVL, PWLV and PTH level (r = 0.7, p <0.005), LV E' and PTH level (r = 0.7, p < 0.005). Inverse correlations were found between the level of PTH and IS (r = -0.5, p < 0.005), LVMI (r = -0.5, p < 0.005), and the level of vitamin D and VDDT (r = -0.6, p < 0.005). Direct correlations in OA were found between the level of CRP and PVAdiast (r = 0.6, p < 0.005), and the level of sUA (r = 0.7, p < 0.005), and the level of vitamin D and E/E'LV (r = 0.6, p < 0.005). A high prevalence of LV and RV DD was found in patients with CPPD and OA. The presence of DD in CPPD was associated with lower vitamin D levels, and in OA with a higher level of sUA and a lower level of PTH.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice.

OBJECTIVE: To summarise current data regarding the use of imaging in crystal-induced arthropathies (CiAs) informing a European Alliance of Associations for Rheumatology task force. METHODS: We performed four systematic searches in Embase, Medline and Central on imaging for diagnosis, monitoring, prediction of disease severity/treatment response, guiding procedures and patient education in gout, calcium pyrophosphate dihydrate deposition (CPPD) and basic calcium phosphate deposition (BCPD). Records were screened, manuscripts reviewed and data of the included studies extracted. The risk of bias was assessed by validated instruments. RESULTS: For gout, 88 studies were included. Diagnostic studies reported good to excellent sensitivity and specificity of dual-energy CT (DECT) and ultrasound (US), high specificity and lower sensitivity for conventional radiographs (CR) and CT. Longitudinal studies demonstrated sensitivity to change with regard to crystal deposition by US and DECT and inflammation by US and structural progression by CR and CT. For CPPD, 50 studies were included. Diagnostic studies on CR and US showed high specificity and variable sensitivity. There was a single study on monitoring, while nine assessed the prediction in CPPD. For BCPD, 56 studies were included. There were two diagnostic studies, while monitoring by CR and US was assessed in 43 studies, showing a reduction in crystal deposition. A total of 12 studies with inconsistent results assessed the prediction of treatment response. The search on patient education retrieved two studies, suggesting a potential role of DECT. CONCLUSION: This SLR confirmed a relevant and increasing role of imaging in the field of CiAs.

Acute coronary syndrome in calcium pyrophosphate deposition disease patients: A US inpatient care cohort study.

OBJECTIVE: Recent studies have shown that CPPD might be associated with a higher risk of cardiovascular events related to inflammation. Thus, we aim to examine the outcomes of patients admitted for acute coronary syndrome (ACS) with and without CPPD. METHODS: We used data from the US National Inpatient Sample (NIS) Database to identify patients who were admitted for ACS between 2006 and 2019. The ICD-9 and -10 codes were used to determine the patients with ACS related hospitalizations and of those, we classified two groups of patients: those with and those without any CPPD code. Data collection included demographics and comorbidities. Outcomes were in-hospital mortality, length of stay, hospital charges, and in-hospital complications. Associations between CPPD and specific morbidity were evaluated with chi-square tests. T-tests were used for continuous variables. We have also presented odds ratio (OR) along with 95 % confidence intervals (CI) for the outcomes of interest. RESULTS: A total of 17,322,362 patients were admitted for ACS. Among them, 7,458 had CPPD, with a mean age of 75 years and 48 % were females. CPPD patients were more likely to be older (75 vs 68 years; p < 0.001) compared to non-CPPD patients. Among the comorbidities, chronic kidney disease was more frequently observed in CPPD patients. Regarding the inpatient complications, acute ischemic stroke and post-procedural hemorrhage were more frequently seen in CPPD patients. Interestingly, the in-hospital mortality was lower in the CPPD patients than the non-CPPD patients (OR: 0.77; CI 95 % 0.70-0.85). ACS in CPPD patients was associated with a longer mean length of stay than those without CPPD (OR: 3.35; 95 % CI 3.17-3.53). In addition, mean total charges were higher in the CPPD group (OR: 1.04; 95 % CI 1.01-1.10). CONCLUSION: ACS in CPPD patients is associated with higher healthcare utilization, including cost and length of hospital stay, and lower in-hospital mortality than non-CPPD patients.

Diagnostic Accuracy of Raman Spectroscopy Integrated With Polarized Light Microscopy for Calcium Pyrophosphate-Associated Arthritis.

OBJECTIVE: We studied the performance of integrated Raman polarized light microscopy (iRPolM) for the identification of calcium pyrophosphate (CPP)-associated arthritis (CPPD). METHODS: This is a diagnostic accuracy study including 400 consecutive synovial fluid samples from a single hospital in the Netherlands. Accuracy measures were calculated against polarized light microscopy (PLM) and the 2023 American College of Rheumatology (ACR)/EULAR criteria set for CPPD. RESULTS: The interrater reliability between iRPolM and the 2023 ACR/EULAR criteria set for CPPD was strong (κ = 0.88). The diagnostic performance of iRPolM compared to the 2023 ACR/EULAR criteria set was sensitivity 86.0% (95% confidence interval [CI] 73.3-94.2), specificity 99.1% (95% CI 97.5-99.8), positive likelihood ratio 100.33 (95% CI 32.3-311.3), negative likelihood ratio 0.14 (95% CI 0.07-0.28), positive predictive value 93.5% (95% CI 82.2-97.8), negative predictive value 98.0% (95% CI 82.2-97.8), and accuracy 97.5% (95% CI 95.5-98.8). We allowed rheumatologists to rate the certainty of their microscopic identification of CPP and found a large correspondence between iRPolM and a certain identification (κ = 0.87), whereas only 10% of the uncertain CPP identifications could be confirmed with iRPolM. We identified several novel particle types in synovial fluid analysis, including calcium carbonate crystals, deposited carotenoids, microplastics, and three types of Maltese cross birefringent objects. CONCLUSION: iRPolM can easily identify CPP crystals with a strong diagnostic performance. PLM alone is not specific enough to reliably resolve complicated cases, and the implementation of Raman spectroscopy in rheumatology practice can be of benefit to patients with suspected CPPD.

Full endoscopic surgery for calcium pyrophosphate deposition disease (CPPD) in the cervical ligamentum flavum: report of two cervical myelopathy cases.

Calcium pyrophosphate deposition disease (CPPD), known as pseudogout, is characterized by the accumulation of calcium pyrophosphate crystals in musculoskeletal structures, primarily joints. While CPPD commonly affects various joints, involvement in the cervical spine leading to myelopathy is rare. Surgical intervention becomes necessary when conservative measures fail, but reports on full endoscopic surgeries are extremely rare. We present two successful cases where full endoscopic systems were used for CPPD removal in the cervical spine. The surgical technique involved a full endoscopic approach, adapting the previously reported technique for unilateral laminotomy bilateral decompression. Full-endoscopic removal of cervical CPPD inducing myelopathy were successfully removed with good clinical and radiologic outcomes. The scarcity of endoscopic cases for cervical ligamentum flavum CPPD is attributed to the condition's rarity. However, our successful cases advocate for endoscopic surgery as a potential primary treatment option for CPPD-induced cervical myelopathy, especially in elderly patients or those with previous cervical operation histories. This experience encourages the consideration of endoscopic surgery for managing cervical ligamentum flavum CPPD as a viable alternative.

Describing calcium pyrophosphate deposition: undoing the tower of Babel!

PURPOSE OF REVIEW: In 1977, McCarty astutely observed, 'The variety of names suggested for the condition associated with deposits of calcium pyrophosphate dihydrate crystals is exceeded only by the variations of its clinical presentation'. Fast forward to 2024, a standardized nomenclature for calcium pyrophosphate deposition (CPPD) is still lacking. This review aims to delineate the challenges in characterizing CPPD through nomenclature and imaging. RECENT FINDINGS: Despite the effort of nomenclature standardization in 2011 by the EULAR, confusion persists in the literature and clinical practice, with pseudo-forms and obscure abbreviations. The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) has launched a project to redefine CPPD nomenclature and formulate a user-friendly language for effective communication with patients and other stakeholders. Additionally, recent advancements in imaging, have shed light on various aspects of the disorder. SUMMARY: Almost 60 years from the first description of a clinical manifestation related to calcium pyrophosphate crystals, a common language describing the disorder is still lacking. A redefined CPPD nomenclature, together with lay-friendly terminology, would significantly contribute to the uniformity of CPPD research, enhance public understanding and awareness and improve doctor-patient communication and therefore disease outcomes. Imaging can provide deep insights into CPPD elements, promoting comprehension of this disorder.

Middle Ear Tophi: A Case Series of Two Unusual Lesions and a Report of Facial Weakness and Review of the Literature.

OBJECTIVE: Tophaceous lesions of the middle ear from calcium pyrophosphate deposition disease (CPPD, or pseudogout) and gout are infrequently reported. Recognizing its characteristic findings will allow clinicians to accurately narrow the differential diagnosis of bony-appearing middle ear lesions and improve management. PATIENTS: Two consecutive cases of tophaceous middle ear lesions presenting to a tertiary care center between January 2021 and December 2021. Neither with previous rheumatologic history. INTERVENTIONS: Surgical excision of tophaceous middle ear lesions. MAIN OUTCOME MEASURE: Improvements in facial weakness and conductive hearing loss. RESULTS: The first case was a 66-year-old gentleman with progressive conductive loss, ipsilateral progressive facial weakness over years, and an opaque, irregular-appearing tympanic membrane anterior to the malleus found to have CPPD on surgical pathology, with immediate postoperative improvement of facial function. The second was a 75-year-old gentleman with progressive conductive loss and similar appearing tympanic membrane as case 1, previously diagnosed with tympanosclerosis, found to have gout on surgical pathology. In both cases, the CT showed a heterogenous, bony-appearing lesion in the middle ear, and both tophaceous lesions were a of gritty, chalky consistency intraoperatively. CONCLUSION: Tophaceous lesions of the middle ear are rare but have similar findings. Notably, the tympanic membrane can appear opaque and irregular, and the CT demonstrates a radiopaque, heterogeneous appearance. Facial weakness is an unusual finding. Specimens of suspected tophi must be sent to pathology without formalin for accurate diagnosis.

Crystal induced arthropathies-a comparative study of 40 patients with apatite rheumatism, chondrocalcinosis and primary synovial chondromatosis.

Introduction: Apatite rheumatism (AR), chondrocalcinosis (Ch-C), and primary synovial chondromatosis (prSynCh) are regarded as distinct clinical entities. The introduction of the non-staining technique by Bély and Apáthy (2013) opened a new era in the microscopic diagnosis of crystal induced diseases, allowing the analysis of MSU (monosodium urate monohydrate) HA (calcium hydroxyapatite), CPPD (calcium pyrophosphate dihydrate) crystals, cholesterol, crystalline liquid lipid droplets, and other crystals in unstained sections of conventionally proceeded (aqueous formaldehyde fixed, paraffin-embedded) tissue samples. The aim of this study was to describe the characteristic histology of crystal deposits in AR, Ch-C, and prSynCh with traditional stains and histochemical reactions comparing with unstained tissue sections according to Bély and Apáthy (2013). Patients and methods: Tissue samples of 4 with apatite rheumatism (Milwaukee syndrome), 16 with chondrocalcinosis, and 20 with clinically diagnosed primary synovial chondromatosis were analyzed. Results and conclusion: Apatite rheumatism, chondrocalcinosis, and primary synovial chondromatosis are related metabolic disorders with HA and CPPD depositions. The authors assume that AR and Ch-C are different stages of the same metabolic disorder, which differ from prSynCh in amorphous mineral production, furthermore in the production of chondroid, osteoid and/or bone. prSynCh is a defective variant of HA and CPPD induced metabolic disorders with reduced mineralization capabilities, where the deficient mineralization is replaced by chondroid and/or bone formation. The non-staining technique of Bély and Apáthy proved to be a much more effective method for the demonstration of crystals in metabolic diseases than conventional stains and histochemical reactions.

[First classification criteria for diseases caused by calcium pyrophosphate deposition (CPPD)-Translation, explanation and assessment]. / Erste Klassifikationskriterien für durch Kalziumpyrophosphatablagerungen verursachte Erkrankungen ­ Übersetzung, Erläuterung und Bewertung.

AIM: For diseases caused by calcium pyrophosphate deposition (CPPD), validated classification criteria were previously lacking. In this article the recently developed and validated classification criteria are translated, explained, and assessed. METHODS: In recent years a multinational research group developed classification criteria for CPPD disease with the support by the European Alliance of Associations for Rheumatology (EULAR) and the American College of Rheumatology (ACR), following an established method. The developed criteria were finally validated in an independent cohort. The translation and annotation of the new first classification criteria were carried out in an iterative procedure in consensus with the authors. RESULTS: The presence of a crowned dens syndrome or calcium pyrophosphate crystals in the synovial fluid in patients with pain, swelling or sensitivity of the joints (entry criterion) is sufficient for the classification as CPPD disease, where the symptoms cannot be completely explained by another rheumatic disease (exclusion criterion). If these symptoms are not present, a count of more than 56 points based on weighted criteria comprised of clinical features and the results of laboratory and imaging investigations can be included for classification as a CPPD disease. These criteria had a sensitivity of 92.2% and a specificity of 87.9% in the derivation cohorts (190 CPPD cases and 148 mimics), whereas the sensitivity was 99.2% and the specificity 92.5% in the validation cohorts (251 CPPD cases and 162 mimics). CONCLUSION: The ACR/EULAR classification criteria 2023 of a CPPD disease will facilitate clinical research in this field. The use in the clinical routine will show how practical the criteria are.

2023 EULAR recommendations on imaging in diagnosis and management of crystal-induced arthropathies in clinical practice.

OBJECTIVE: To formulate evidence-based recommendations and overarching principles on the use of imaging in the clinical management of crystal-induced arthropathies (CiAs). METHODS: An international task force of 25 rheumatologists, radiologists, methodologists, healthcare professionals and patient research partners from 11 countries was formed according to the EULAR standard operating procedures. Fourteen key questions on the role of imaging in the most common forms of CiA were generated. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease. Imaging modalities included conventional radiography, ultrasound, CT and MRI. Experts applied research evidence obtained from four systematic literature reviews using MEDLINE, EMBASE and CENTRAL. Task force members provided level of agreement (LoA) anonymously by using a Numerical Rating Scale from 0 to 10. RESULTS: Five overarching principles and 10 recommendations were developed encompassing the role of imaging in various aspects of patient management: making a diagnosis of CiA, monitoring inflammation and damage, predicting outcome, response to treatment, guided interventions and patient education. Overall, the LoA for the recommendations was high (8.46-9.92). CONCLUSIONS: These are the first recommendations that encompass the major forms of CiA and guide the use of common imaging modalities in this disease group in clinical practice.

A rare case of intervertebral disc calcification combined with ossification of the posterior longitudinal ligament in a child: a case report and literature review.

BACKGROUND: Intervertebral disc calcification (IDC) combined with calcification in children has been sporadically reported, while ossification of the posterior longitudinal ligament (OPLL) in the cervical spine in pediatric patients is exceedingly rare. The aim of this study is to investigate the potential prognosis and outcomes associated with this condition. CASE PRESENTATION: We present an unusual case involving a 10-year-old Chinese child diagnosed with calcified cervical disc herniation and ossification of the posterior longitudinal ligament. Conservative treatment measures were implemented, and at the 1-month and 6-month follow-up, the patient's pain exhibited significant improvement. Subsequent cervical MRI and CT scans revealed the complete disappearance of OPLL and substantial absorption of the calcified disc. During the three-month follow-up, CT demonstrated slight residual disc calcification, however, the patient remained asymptomatic with no discernible limitation in cervical motion. CONCLUSIONS: We conducted a comprehensive review of several cases presenting with the same diagnosis. It is noteworthy that IDC combined with OPLL in children constitutes a rare clinical entity. Despite imaging indications of potential spinal canal occupation, the majority of such cases demonstrate complete absorption following conservative treatment, with OPLL exhibiting a faster absorption rate than calcified discs.

Fractures in Patients With Acute Calcium Pyrophosphate Crystal Arthritis Versus Matched Comparators in a Large Cohort Study.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease was associated with osteopenia in two cross-sectional studies. We compared fracture risks in patients with acute calcium pyrophosphate (CPP) crystal arthritis versus matched comparators. METHODS: We performed a longitudinal cohort study using electronic health record data from a single large academic health system, with data from 1991 to 2023. Patients with one or more episodes of acute CPP crystal arthritis were matched to comparators on the index date (first documentation of "pseudogout" or synovial fluid CPP crystals or matched encounter) and first encounter in the health system. The primary outcome was first fracture at the humerus, wrist, hip, or pelvis. We excluded patients with fracture before the index date. Covariates included demographics, body mass index, smoking, comorbidities, health care use, glucocorticoids, and osteoporosis treatments. We estimated incidence rates and adjusted hazard ratios for fracture. Sensitivity analyses excluded patients prescribed glucocorticoids, patients prescribed osteoporosis treatments, or patients with rheumatoid arthritis and additionally adjusted for chronic kidney disease. RESULTS: We identified 1,148 patients with acute CPP crystal arthritis matched to 3,730 comparators, with a mean age of 73 years. Glucocorticoids and osteoporosis treatments were more frequent in the acute CPP crystal arthritis cohort. Fracture incidence rates were twice as high in the acute CPP crystal arthritis cohort (11.7 per 1,000 person-years) versus comparators (5.5 per 1,000 person-years). After multivariable adjustment, fracture relative risk was twice as high in the acute CPP crystal arthritis cohort (hazard ratio 1.8 [95% confidence interval 1.3-2.3]); results were similar in sensitivity analyses. CONCLUSION: In this first published study of fractures and CPPD, fracture risk was nearly doubled in patients with acute CPP crystal arthritis.

Calcified Chondroid Mesenchymal Neoplasms.

Calcified chondroid mesenchymal neoplasms (CCMN) represent a morphologic spectrum of related tumors. Historically, chondroid matrix or chondroblastoma-like features have been described in soft tissue chondroma, tenosynovial giant cell tumors (especially of the temporomandibular joint (TMJ) region), and in a subset of tophaceous pseudogout. Recently, these tumors have been found to share FN1-receptor tyrosine kinase (RTK) fusions. This review discusses the clinical, morphologic, immunohistochemical, and molecular genetic features of CCMN. The distinction from morphologic mimics is also discussed.

Safety and efficacy of colchicine in crystal-induced arthritis flare in 54 patients with severe chronic kidney disease.

INTRODUCTION: Colchicine, commonly used in gout flare, is contraindicated in severe chronic kidney disease (CKD) (estimated glomerular filtration rate <30 mL/min). However, in this context, there are few alternatives, and colchicine use persists. We evaluated the tolerance of colchicine and its efficacy in patients with severe CKD. PATIENTS AND METHODS: All prescriptions of colchicine for managing crystal-induced arthritis flare (gout or calcium pyrophosphate deposition (CPPD) disease) in a hospitalised patient with severe CKD were screened from September 2020 to September 2021. After patient consent and treatment information, clinical and biological safety and efficacy data were prospectively collected from day 1 (D1) to D11. RESULTS: We included 54 patients (median age 75 years (IQR 67-83)) with 62 colchicine prescriptions (cases). Twelve (22%) patients were on dialysis. The main reason for hospitalisation was heart failure (31.5%), acute renal failure (22.2%), infection (18.5%) or an acute joint episode (9.3%). In total, 59.3% of patients had diabetes. The prescriptions concerned 58 cases of gout flares, 1 case of CPPD and 3 cases of both. Initial colchicine dosages were ≤0.5 mg/day in 47/62 (75.8%) cases; no dosage exceeded 1 mg/day (median duration of 6 days (IQR 3-11)). Colchicine was well tolerated in 47/61 (77%) cases. No serious adverse event was reported. Colchicine was considered completely effective by the medical team in 48/58 (83%) of cases. CONCLUSION: The use of colchicine, at reduced doses, was mostly effective to treat crystal-induced arthritis flare in 54 patients with severe CKD and was well tolerated, without any serious adverse events.