High frequency of BCP, but less CPP crystal-mediated calcification in cartilage and synovial membrane of osteoarthritis patients.

OBJECTIVE: Ectopic articular calcification is a common phenomenon of osteoarthritic joints, and closely related to disease progression. Identification of the involved calcium crystal types represents an important topic in research and clinical practice. Difficulties in accurate detection and crystal type identification have led to inconsistent data on the prevalence and spatial distribution of Basic calcium phosphate (BCP) and calcium pyrophosphate (CPP) deposition. METHOD: Combining multiple imaging methods including conventional radiography, histology and Raman spectroscopy, this study provides a comprehensive analysis of BCP and CPP-based calcification, its frequency and distribution in cartilage and synovial membrane samples of 92 osteoarthritis patients undergoing knee replacement surgery. RESULTS: Conventional radiography showed calcifications in 35% of patients. Von Kossa staining detected calcified deposits in 88% and 57% of cartilage and synovial samples, respectively. BCP crystals presented as brittle deposits on top of the cartilage surface or embedded in synovial tissue. CPP deposits appeared as larger granular needle-shaped clusters or dense circular pockets below the cartilage surface or within synovial tissue. Spectroscopic analysis detected BCP crystals in 75% of cartilage and 43% of synovial samples. CPP deposition was only detected in 18% of cartilage and 15% of synovial samples, often coinciding with BCP deposits. CONCLUSION: BCP is the predominant crystal type in calcified cartilage and synovium while CPP deposition is rare, often coinciding with BCP. Distinct and qualitative information on BCP and CPP deposits in joint tissues gives rise to the speculation that different disease entities are involved that might need different treatment strategies.

Calcium pyrophosphate crystal deposition with rotator cuff tear-A case report.

Calcium pyrophosphate dihydrate (CPPD) deposition disease is an inflammatory arthritis induced by calcium pyrophosphate (CPP) crystals and clinically it is called pseudogout. It usually deposits in articular cartilage and in periarticular soft tissues. But no cases of pseudogout in the rotator cuff without cartilage deposition or destruction have been reported so far. We present a case of a 57-year-old woman who was diagnosed as pseudogout with rotator cuff tear.

Chondrocalcinosis does not affect functional outcome and prosthesis survival in patients after total or unicompartmental knee arthroplasty: a systematic review.

PURPOSE: There are contentious data about the role calcium pyrophosphate (CPP) crystals and chondrocalcinosis (CC) play in the progression of osteoarthritis (OA), as well as in the outcomes after knee arthroplasty. Hence, the purpose of this systematic review was to analyse the clinical and functional outcome, progression of OA and prosthesis survivorship after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in patients with CC compared to patients without CC. METHODS: A systematic review of the literature in PubMed, Medline, Embase and Web of Science was performed using the "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" (PRISMA) guidelines. Articles which reported the outcome and survival rates of prosthesis after TKA or UKA in patients with CC were included. RESULTS: A total of 3718 patient knees were included in eight selected publications, with a median sample sizes of 234 knees (range 78-1000) and 954 knees (range 408-1500) for publications including UKA and TKA, respectively. At time of surgery, the mean age was 69 years and the prevalence for CC ranged from 12.6 to 36%. Chondrocalcinosis did not significantly influence the functional and clinical outcome, the implant survival as well as the radiologic progression of OA disease after UKA and TKA. CONCLUSION: The presence of CPP crystals in tissue samples, synovial fluid or evidence of calcifications on preoperative radiographs did not significantly influence the postoperative functional and activity scores. It also had no significant influence on prosthesis survival rate, whether it was a UKA or a TKA. This study shows that the impact of a subclinical form of chondrocalcinosis may not be of clinical relevance in the context of arthroplasty. LEVEL OF EVIDENCE: IV.

Magnetic resonance imaging of rheumatological diseases.

Magnetic resonance imaging (MRI) is extremely useful in the early diagnosis of rheumatologic diseases, as well as in the monitoring of treatment response and disease progression to optimize long-term clinical outcomes. MRI is highly sensitive and specific in detecting the common findings in rheumatologic diseases, such as bone marrow oedema, cartilage disruption, articular erosions, joint effusions, bursal effusions, tendon sheath effusions, and synovitis. This imaging modality can demonstrate structural changes of cartilage and bone destruction years earlier than radiographs. Rheumatoid arthritis, crystal deposition diseases (including gouty arthropathy and calcium pyrophosphate deposition disease), seronegative spondyloarthropathies (including psoriatic arthritis, reactive arthritis, ankylosing spondylitis), and osteoarthritis have characteristic appearances on MRI. Contrast-enhanced MRI and diffusion-weighted imaging can provide additional evaluation of active synovitis. This article describes the MRI findings of normal joints, as well as the pathophysiological mechanisms and typical MRI findings of rheumatoid arthritis, gouty arthritis, calcium pyrophosphate deposition disease, psoriatic arthritis, reactive arthritis, ankylosing spondylitis, and osteoarthritis.

Rare presentation of intradural calcium pyrophosphate dihydrate crystal deposition.

Calcium pyrophosphate dihydrate crystal deposition (CPPD), also known as pseudogout, can have spinal manifestations in roughly one quarter of patients. We present a rare, intradural manifestation of CPPD requiring surgical intervention, with a review of pertinent differential diagnoses on imaging. A 48-year-old male presented with urinary retention, and was found to have an intradural lesion with peripheral enhancement on gadolinium T1-weighted magnetic resonance imaging. Due to the patient's progressive neurological deterioration, he was taken for a minimally invasive approach for resection of the lesion. Histopathological analysis revealed crystal deposits with rhomboidal birefringence consistent with CPPD. The imaging features of this lesion were atypical for any of the traditional intradural extramedullary lesions. Typically seen extradurally, recognizing CPPD as a potential culprit for intradural compression is helpful to recognize for providers.

Multilevel calcium pyrophosphate dihydrate deposition in cervical ligamentum flavum: clinical characteristics and imaging features.

BACKGROUND: Involvement in cervical ligamentum flavum is a rare manifestation of the calcium pyrophosphate dihydrate deposition disease. Only few cases of this condition have been reported. We revealed eighteen cases of CPPD in cervical ligamentum flavum that diagnosed at a single medical center. In our case series, clinical characteristics and magnetic resonance imaging findings of patients are described. METHODS: We retrospectively reviewed the medical charts and imaging studies of the eighteen patients with pseudogout attack of the cervical ligamentum flavum. In addition, we discussed the differences between this disease and ossification of ligamentum flavum in image manifestations. RESULTS: There were fourteen men and four women aged between 59 and 87 years. Diabetes mellitus and hypertension were the most common comorbidities. Myelopathy and neck pain were presented in most patients. C4-5 and C5-6 were attacked most frequently, and multiple- rather than single-level involvement could be observed in our series. "Acute on chronic phenomenon" was a specific magnetic resonance image finding in patients whose symptom durations were between 2 to 5 months. Compared to ossification of ligamentum flavum, calcium pyrophosphate dihydrate crystal deposition had different image signs, including morphology, side of the involved ligament, no continuity with the lamina, acute on chronic phenomenon, and presence of retro-odontoid mass. CONCLUSIONS: Nodular calcifications in cervical ligamentum flavum raise highly suspicion for calcium pyrophosphate dihydrate deposition and must be diagnosed by histological examination and polarized light microscopy. This disease is different from ossification of ligamentum flavum, and it could be recognized by specific image features.

There is no difference in postoperative pain, function and complications in patients with chondrocalcinosis in the outcome of total knee arthroplasty for end-stage osteoarthritis.

PURPOSE: Chondrocalcinosis is the radiographic appearance of calcium crystals in cartilage and other soft tissue. It is suggested that preoperative chondrocalcinosis predicts a worse outcome after total knee arthroplasty and it is unclear if chondrocalcinosis leads to more postoperative complications. This study aimed to compare function, pain, postoperative complications, postoperative signs of acute arthritis and revision rates between patients with and without chondrocalcinosis undergoing total knee arthroplasty for osteoarthritis. METHODS: In this retrospective cohort study performed in 2017, 408 knees in 392 patients (16 bilateral total knee arthroplasties) were included. None of the patients received additional synovectomy. PROMs were evaluated after 1 year (n = 294) and 5 years (n = 308). The follow-up for clinical data was 5 years (n = 408). The range of final follow-up was 57-84 months. All preoperative radiographs were scored for chondrocalcinosis and Oxford Knee Score, Knee Society Score and Algofunctional Index were used to assess outcome. All clinical records were screened for postoperative complications (excessive wound discharge, infection, loosening, PAO, stiffness), arthritis after surgery and reoperation or revision for any reason. RESULTS: Sixty-three knees (15.4%) showed signs of chondrocalcinosis. Male gender, higher age and lower BMI were risk factors for chondrocalcinosis. No difference was found in Oxford Knee Score, Knee Society Score and Algofunctional Index, nor in postoperative complications, postoperative signs of acute arthritis and revision rate. CONCLUSION: Patients with and without chondrocalcinosis have the same outcome after total knee arthroplasty related to pain, functionality, complications, arthritis and revision after surgery for end-stage osteoarthritis. Chondrocalcinosis is not a contraindication for total knee arthroplasty and additional synovectomy is unnecessary. LEVEL OF EVIDENCE: III.

Calcium Pyrophosphate Dihydrate Crystals Increase the Granulocyte/Monocyte Progenitor (GMP) and Enhance Granulocyte and Monocyte Differentiation In Vivo.

Calcium pyrophosphate dihydrate (CPPD) crystals are formed locally within the joints, leading to pseudogout. Although the mobilization of local granulocytes can be observed in joints where pseudogout has manifested, the mechanism of this activity remains poorly understood. In this study, CPPD crystals were administered to mice, and the dynamics of splenic and peripheral blood myeloid cells were analyzed. As a result, levels of both granulocytes and monocytes were found to increase following CPPD crystal administration in a concentration-dependent manner, with a concomitant decrease in lymphocytes in the peripheral blood. In contrast, the levels of other cells, such as dendritic cell subsets, T-cells, and B-cells, remained unchanged in the spleen, following CPPD crystal administration. Furthermore, an increase in granulocytes/monocyte progenitors (GMPs) and a decrease in megakaryocyte/erythrocyte progenitors (MEPs) were also observed in the bone marrow. In addition, CPPD administration induced production of IL-1ß, which acts on hematopoietic stem cells and hematopoietic progenitors and promotes myeloid cell differentiation and expansion. These results suggest that CPPD crystals act as a "danger signal" to induce IL-1ß production, resulting in changes in course of hematopoietic progenitor cell differentiation and in increased granulocyte/monocyte levels, and contributing to the development of gout.

Identification of adenine-N9-(methoxy)ethyl-ß-bisphosphonate as NPP1 inhibitor attenuates NPPase activity in human osteoarthritic chondrocytes.

Overproduction of extracellular diphosphate due to hydrolysis of ATP by NPP1 leads to pathological calcium diphosphate (pyrophosphate) dihydrate deposition (CPPD) in cartilage, resulting in a degenerative joint disease that today lacks a cure. Here, we targeted the identification of novel NPP1 inhibitors as potential therapeutic agents for CPPD deposition disease. Specifically, we synthesized novel analogs of AMP (NPP1 reaction product) and ADP (NPP1 inhibitor). These derivatives incorporate several chemical modifications of the natural nucleotides including (1) a methylene group replacing the Pα,ß-bridging oxygen atom to provide metabolic resistance, (2) sulfonate group(s) replacing phosphonate(s) to improve binding to NPP1's catalytic zinc ions, (3) an acyclic nucleotide analog to allow flexible binding in the NPP1 catalytic site, and (4) a benzimidazole base replacing adenine. Among the investigated compounds, adenine-N9-(methoxy)ethyl-ß-bisphosphonate, 10, was identified as an NPP1 inhibitor (Ki 16.3 µM vs. the artificial substrate p-nitrophenyl thymidine-5'-monophosphate (p-Nph-5'-TMP), and 9.60 µM vs. the natural substrate, ATP). Compound 10 was selective for NPP1 vs. human NPP3, human CD39, and tissue non-specific alkaline phosphatase (TNAP), but also inhibited human CD73 (Ki 12.6 µM). Thus, 10 is a dual NPP1/CD73 inhibitor, which could not only be of interest for treating CPPD deposition disease and calcific aortic valve disease but may also be considered for the immunotherapy of cancer. Compound 10 proved to be a promising inhibitor, which almost completely reduces NPPase activity in human osteoarthritic chondrocytes at a concentration of 100 µM.

An investigation of the independent risk factors that differentiate gout from pseudogout in patients with crystal-induced acute arthritis: a cross-sectional study.

OBJECTIVES: To identify independent risk factors that differentiate gout from pseudogout in patients that present with crystal-induced acute arthritis. METHODS: This cross-sectional study was conducted at Siriraj Hospital (Bangkok, Thailand) during the 25 May 2014-28 November 2014 study period. Patients who presented with crystal-induced acute arthritis were eligible for inclusion. Diagnosis of gout or pseudogout was made by microscopic visualization and analysis of crystals in synovial fluid. Patients with other causes of acute arthritis were excluded. Patients diagnosed with gout were compared with patients diagnosed with pseudogout and factors with a p value less than 0.05 were included in logistic regression analysis. RESULTS: A total of 103 patients were included. Gout and pseudogout were established in 59 (56.7%) and 44 (42.3%) patients, respectively. Gout patients were younger than pseudogout patients (66.9 ± 14.5 vs. 78.9 ± 12.0 years; p = 0.0001); had higher BMI (22.9 ± 2.5 vs. 21.0 ± 2.5 kg/m2; p = 0.001); had history of recurrent arthritis (91.5 vs. 9.1%; p = 0.001); had higher prevalence of below-knee arthritis (66.1 vs. 31.8%; p = 0.001); had less periarticular soft tissue swelling (57.6 vs. 81.8%; p = 0.01); and had hyperuricemia (8.0 ± 2.5 vs. 5.6 ± 2.7; p = 0.001). In adjusted multivariate analysis, hyperuricemia during acute arthritis/gouty attack characterized gout (OR 2.08, 95% CI 1.2-3.6), while monoarticular attack (OR 4.12, 95% CI 1.3-13.0) and periarticular soft tissue swelling (OR 4.03, 95% CI 1.1-14.9) were indications for pseudogout. CONCLUSIONS: The independent risk factors were found to differentiate gout from pseudogout: Gout: hyperuricemia during gouty attack; Pseudogout: monoarticular attack and periarticular soft tissue swelling.

Tumoral pseudogout of the proximal interphalangeal joint of a finger: a case report and literature review.

Tumoral pseudogout is a rare clinical form of calcium pyrophosphate dihydrate crystal deposition disease. Tumoral pseudogout can mimic other diseases such as chondroid tumor, tophaceous gout, or tumoral calcinosis. Its radiological features have been presented in some case reports, but no specific radiographic features have been identified. Here, we report an unusual case of recurrent tumoral pseudogout involving the proximal interphalangeal joint of the right long finger. This case presents with progressive radiological findings of the disease with an enlarging and recurrent calcified mass and secondary bony erosion and remodeling, along with a radiological-pathological correlation. We also review previously reported imaging findings of this disease entity, differential points in comparison to other diseases, and some key points for making the correct diagnosis.

The prevalence of and factors related to calcium pyrophosphate dihydrate crystal deposition in the knee joint.

OBJECTIVES: The purpose of this study was to reveal the accurate prevalence and related factors to the presence of calcium pyrophosphate dihydrate (CPPD) crystal deposition in cadaveric knee joints. DESIGN: Controlled laboratory study. METHODS: Six hundred and eight knees from 304 cadavers (332 male knees and 276 female knees, formalin fixed, Japanese anatomical specimens) were included in this study. The average age of the cadavers was 78.3 ± 10.7 years. Knees were macroscopically evaluated for the existence of CPPD, and the depth of cartilage degeneration of the femoro-tibial joint following the Outerbridge's classification. CPPD crystal was confirmed under Fourier transform infrared spectroscopy (FTIR) analysis using light microscopy. Statistical analysis was performed to reveal the correlation between the occurrence of CPPD deposition in the knee joint and gender, age, and the depth of cartilage degeneration of the femoro-tibial joint. RESULTS: The prevalence of grossly visible CPPD crystal was 13% (79 knees). In all of these knees, CPPD crystal was confirmed under FTIR analysis. Statistical analysis showed significant correlation between the occurrence of CPPD deposition and gender (P < 0.001), and depth of cartilage degeneration in the femoro-tibial joint (P < 0.001). In the cartilage degeneration positive knees (Over grade 3 in Outerbridge's classification), average age of CPPD deposition knee was significantly higher than CPPD negative knees. CONCLUSIONS: In this study, the prevalence of CPPD deposition disease was evaluated in a relatively large sample size of cadaveric knees. The prevalence of CPPD deposition disease was 13%, and was significantly correlated with the subject's age, gender, and severity of cartilage degeneration in the femoro-tibial joint.

Calcium pyrophosphate crystal arthritis associated with immune checkpoint inhibitor successfully treated with intra-articular glucocorticoid: A case report.

Immune checkpoint inhibitors (ICIs) sometimes induce immune-related adverse events (irAEs), and arthritis is one of the irAE symptoms. Recently, crystal-induced arthritis, such as calcium pyrophosphate (CPP) crystal deposition disease and gout, has been reported to occur after ICI administration. However, the distinction between ICI-associated crystal arthritis and ICI-induced non-crystal arthritis is difficult because their symptoms are similar. Besides, optimal treatment for ICI-associated crystal arthritis has not been established. Here, we report a patient who developed CPP crystal arthritis twice after pembrolizumab (ICI) administration and was successfully treated with intra-articular glucocorticoid injection. He suffered arthritis and acute interstitial nephritis simultaneously after ICI administration. Musculoskeletal ultrasound of his affected joint suggests that his arthritis was crystal-induced arthritis, and arthrocentesis detected CPP crystal in synovial fluid. Thus, we diagnosed his arthritis as ICI-associated cystal arthritis. Therefore, our case encourages the use of musculoskeletal ultrasound in patients with arthritis after treatment with ICI because it may distinguish between ICI-associated crystal arthritis and ICI-induced non-crystal arthritis. Besides, ICI-associated crystal arthritis could be treatable by intra-articular glucocorticoid injection.

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.

Diagnosis and Treatment of Calcium Pyrophosphate Deposition (CPPD) Disease: A Review.

Calcium Pyrophosphate Dihydrate (CPPD) crystal-related arthropathies are a common cause of acute and chronic arthritis caused by the deposition of calcium pyrophosphate crystals in joints and soft tissues, resulting in inflammation and joint damage. They present with a wide spectrum of clinical manifestations and often present challenges to diagnosis and management as they commonly affect older co-morbid patients. The challenges are compounded by a lack of a well-defined description of CPPD. However, an international expert-driven process is underway to develop CPPD classification criteria. Treatment is also problematic as unlike gout, there are no agents available that decrease the crystal burden. Treatment options have often been extrapolated from gout treatment pathways without having extensive trials or a solid evidence base. It is hoped the new CPPD classification guidelines will contribute to large multicentre studies, with well-defined patient cohorts, which will facilitate the production of high-quality evidence to guide the management of this condition. Here, we discuss the barriers and facilitators in diagnosing and treating CPPD-related arthropathy.

Synovium to Myocardium: A Case of Calcium Pyrophosphate Dihydrate Crystal Arthritis Associated With Myocardial Infarction.

Both gout and pseudogout are crystal-induced arthropathies. Here, we report a case of acute calcium pyrophosphate dihydrate (CPPD) arthritis associated with type 1 myocardial infarction (MI). An 83-year-old female presented to our emergency department with generalized weakness and bilateral lower extremity edema. Her left foot was noted to be more inflamed compared to the right, with cardinal signs of pain, swelling, erythema, and warmth. A presumptive diagnosis of cellulitis was made, and antibiotics were initiated. Further investigations revealed elevated troponins with new-onset bundle branch block, ST, and T-wave changes on electrocardiogram, indicating a type 1 MI. After a review of the patient's history, imaging of the extremity, elevated inflammatory markers, and the typical distribution and pattern of inflammation, the diagnosis was changed to pseudogout. Steroids and colchicine were initiated, providing instant relief. This case highlights a possible association between cardiovascular disease and pseudogout, emphasizing the need for further studies regarding this relationship. Despite being rare, physicians should be made aware of this relationship, especially in patients with a history of CPPD arthritis presenting with type 1 MI.

Confusion With Presentations of Calcium Pyrophosphate Dihydrate Disease: A Report of Two Cases Mistaken for Cellulitis.

Both pseudogout and cellulitis are diseases that may mimic one another in clinical practice. We discuss two cases of acute calcium pyrophosphate dihydrate (CPPD) arthritis mistaken for cellulitis in the emergency department. Both patients experienced significant improvement after management was changed to treat CPPD. These cases highlight how it is essential for physicians to consider CPPD as a differential diagnosis for a patient that is presenting with signs of inflammation in any joint.

Patient-Reported Outcomes in Calcium Pyrophosphate Deposition Disease Compared to Gout and Osteoarthritis.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease prevalence is similar to that of gout and osteoarthritis (OA), yet CPPD outcomes research greatly lags behind research in these other forms of arthritis. We compared validated patient-reported outcome measures in patients with CPPD vs gout and OA. METHODS: Patients with CPPD were recruited from Brigham and Women's Hospital from 2018 to 2022. Presence of CPPD manifestations (acute calcium pyrophosphate [CPP] crystal arthritis, chronic CPP inflammatory arthritis, and/or OA with CPPD) was confirmed by medical record review. Baseline surveys included the Gout Assessment Questionnaire version 2.0, modified to ask about "pseudogout" rather than "gout"; Routine Assessment of Patient Index Data 3 (RAPID-3); and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We compared responses in patients with CPPD against published gout and OA cohort studies. RESULTS: Among 47 patients with CPPD, the mean age was 71.9 years and 51% were female. Sixty-eight percent had at least 1 episode of acute CPP crystal arthritis, 40% had chronic CPP inflammatory arthritis, and 62% had OA with CPPD. Pain visual analog scale scores during a flare were similar in CPPD (mean 6.8 [SD 1.9]) and gout (mean 6.7 [SD 2.6]; P = 0.78). Patients with CPPD reported significantly greater unmet treatment need than patients with gout (P = 0.04). RAPID-3 scores in CPPD (mean 8.1 [SD 5.6]) were lower than in gout (mean 12.1 [SD 6.2]; P < 0.01) and similar in OA (mean 6.8 [SD 6.1]; P = 0.30). Patients with CPPD had significantly worse WOMAC stiffness scores than patients with mild OA, and significantly better WOMAC function scores than patients with severe OA. CONCLUSION: Patients with CPPD may experience pain comparable to that in gout and OA and reported substantial unmet treatment needs.

Orthostatic hypotension as an unusual presentation of spinal calcium pyrophosphate deposition disease: case report and review of literature.

Calcium pyrophosphate crystal deposition disease (CPPD), also known as pseudogout, with spinal involvement, is associated with clinical manifestations of acute nerve compression or chronic spinal stenosis. Precipitation of crystals of calcium pyrophosphate dihydrate in connective tissues can lead to acute inflammatory arthritis, degenerative chronic arthropathies, and radiographic evidence of cartilage calcification. We present a case of an 87-year-old woman, with unstudied chronic polyarthralgia and symptomatic orthostatic hypotension. It were documented acute calcium pyrophosphate deposition wrist arthritis, and cervical CT and MRI was suggestive of spinal involvement of CPPD. Workup excluded other causes of OH. Surgical approach could be indicated to minimize the symptoms, but it was contra-indicated due to the patient's performance status, so histological diagnosis was not possible. Muscle atrophy played an important part in the rapid progression of this insidious chronic disease. Conservative and symptomatic treatment achieve scarce short-term clinical improvement. Spinal involvement of CPPD was thought to be rare but recent studies show a higher prevalence than expected. We call for attention to the extent of structural changes that may occur when not early diagnosed nor treated. High clinical suspicion is required and this is, to our knowledge, the first report of orthostatic hypotension as a presentation of CPPD.

Lumbar Spinal Involvement in Calcium Pyrophosphate Dihydrate Disease: A Systematic Literature Review.

Background: Calcium-pyrophosphate-dihydrate-disease (CPPD) is a crystal-induced arthropathy. The lumbar-spinal involvement is rare and often under-diagnosed. This study aimed to report the case of a lumbar spine CPPD involvement and to perform a systematic review of clinical, imaging features of lumbar involvement in CPPD patients, and treatments that have been implemented. Methods: This systematic review was conducted in accordance with the Preferred-Reporting-Items-for-Systematic-Reviews and Meta-Analyses (PRISMA) guidelines. Results: One hundred and sixty-seven articles met the search criteria using electronic databases searches. We retained 28 articles (20 case reports, 2 case series, 1 family survey, 4 retrospective studies, and 1 prospective study) involving a total of 62 patients. The age ranged between 39 and 89 years old. Among patients with lumbar spine CPPD, 32 were women. The duration of symptoms varied between one day and 8 years. The affection has been discovered during back pain in most cases. In 5 studies, the diagnosis was made on histological specimens of patients operated on for another pathology. X-ray showed calcifications in 2 cases. CT-scan detected calcium deposit in 7 cases. MRI showed lesions going from the increased signal of the disk, to calcified or not-cystic lesion of the facet joints, an intramedullary mass mimicking a schwannoma. Histological examination established the diagnosis of CPPD in 21 patients in all studies. Medical treatment included NSAIDs, Colchicine, Interleukin-1-receptor-antagonist, and antibiotics. Surgery was performed on 13 patients and allowed to establish the histological diagnosis. Conclusion: In the case of inflammatory back pain in elderly subjects, without an infectious gateway, diagnosis of CPPD should be considered, especially for patients with a history of spinal surgery or degenerative radiography changes. CT scan is more sensitive than conventional radiographs. The discovertebral biopsy is the Gold-Standard and should be performed whenever the diagnosis was uncertain. Treatment includes the medical and surgical components.