Diagnóstico de síndrome de Gitelman en paciente con condrocalcinosis / Diagnosis of gitelman syndrome in patient with condrocalcinosis

RESUMEN Introducción: El síndrome de Gitelman es una tubulopatía caracterizada por alcalosis metabólica hipopotasémica, hipomagnesemia e hipocalciuria. Sus efectos musculoesqueléticos son comunes, pudiendo provocar desarrollo de condrocalcinosis. Caso clínico: Paciente con condrocalcinosis de larga data asociada a hipomagnesemia crónica en tratamiento con calcio y magnesio. Tras la suspensión del tratamiento debido a una intervención quirúrgica presentó debilidad generalizada, alcalosis metabólica, hipopotasemia, hipomagnesemia e hipocalciuria con diagnóstico final de síndrome de Gitelman. Tras la instauración de tratamiento, mejoró clínica y analíticamente manteniendo cifras iónicas estables. Discusión y conclusiones: Resulta fundamental un adecuado diagnóstico de este tipo de tubulopatías, ya que un tratamiento adecuado evita complicaciones asociadas.

ABSTRACT Introduction: Gitelman syndrome is a renal tubule disease that involves hypokalaemic metabolic alkalosis, hypomagnesaemia and hypocalciuria. The musculoskeletal effects of Gitelman syndrome are common, including the development of chondrocalcinosis. Clinical case: A female patient with long-standing chondrocalcinosis associated with chronic hypomagnesaemia on treatment with calcium and magnesium. After the suspension of the treatment due to surgery, she presented with a generalised weakness, metabolic alkalosis, hypokalaemia, hypomagnesaemia and hypocalciuria, with final diagnosis of Gitelman syndrome. After re-introducing the treatment, she improved clinically, with electrolytes remaining stable. Discussion and conclusions: A proper diagnosis of this type of tubular diseases is essential because an adequate treatment avoids associated complications.

The Role of Calcium Pyrophosphate Dihydrate Deposition in the Postoperative Outcome of Lumbar Spinal Stenosis Patients

STUDY DESIGN: Retrospective study.PURPOSE: This study aimed to investigate the association of surgical intervention with clinical and quality of life (QoL) outcomes in patients who underwent posterior spinal surgery for lumbar spinal stenosis (LSS) with spinal calcium pyrophosphate dihydrate deposition (SCPPD) versus that in those who underwent the surgery for LSS without SCPPD.OVERVIEW OF LITERATURE: Calcium pyrophosphate (CPP)-associated arthritis is one of the most common types of arthritis. The clinical outcomes are well studied in CPP-associated arthritis of the appendicular joints. However, few studies have investigated SCPPD.METHODS: A single-institution database was reviewed. LSS patients were categorized as those who did and did not have SCPPD, based on histologic identification. Clinical presentations and postoperative results were analyzed. Disability and QoL were assessed using the Oswestry Disability Index (ODI) and the 36-item Short-Form Health Survey.RESULTS: Thirty-four patients were enrolled, with 18 patients being allocated to the SCPPD group and 16 being allocated to the non- SCPPD group. Preoperative and postoperative pain scores were not significantly different between the groups (p=0.33 and p=0.48, respectively). The average preoperative ODI score in the SCPPD group was slightly higher than that in the non-SCPPD group (57 vs. 51, p=0.33); however, the postoperative ODI score was significantly lower (15 vs. 43, p=0.01). The postoperative physical function, vitality, and mental health of the SCPPD patients were also significantly improved (p=0.03, p=0.022, and p=0.022, respectively).CONCLUSIONS: Surgical intervention resulted in good clinical outcomes in SCPPD patients. As per our findings, total removal of CPPinvolved tissue is unnecessary. As such, surgery should be performed as indicated according to clinical presentation without considering the presence of CPPD.

Carpal Tunnel Syndrome Caused by Pseudogout / 대한정형외과학회잡지

Carpal tunnel syndrome (CTS) caused by pseudogout is an uncommon disease. The authors report a 65-year-old female who complained of sudden pain and neurological symptoms on her left hand. Surgical decompression was performed. In the histologic study, a calcium pyrophosphate dihydrate crystal deposit was confirmed. Her pain and neurological symptoms were relieved. Because CTS caused by pseudogout is rare, it is difficult to differentiate it from other diseases. This paper reports an uncommon case of CTS caused by pseudogout.

Síndrome de la apófisis odontoides coronada, una manifestación inusual de dolor cervical: presentación de un caso / Crowned Dens Syndrome, An Unusual Manifestation of Cervical Pain: A Case Report

Las enfermedades por depósito de cristales de pirofosfato dihidratado de calcio o hidroxiapatita se pueden manifestar en cualquier articulación y cuando se acumulan en la columna cervical pueden causar dolor. El síndrome de la apófisis odontoides coronada es una rara condición clínica que consiste en la calcificación en forma de corona de los ligamentos que rodean a la apófisis odontoides. Se describe el caso de un hombre de 70 años de edad con una semana de cervicalgia, cefalea y fiebre, que ingresa por sospecha de patología neurológica. Se realiza TC de cráneo que documenta calcificaciones lentiformes del ligamento transverso del atlas. Se instaura manejo con corticosteroides y antiinflamatorios no esteroideos, con mejoría. Una adecuada anamnesis, junto con estudio por imagen, evita procedimientos innecesarios y permite incluir esta entidad en el diagnóstico diferencial del dolor cervical agudo.

The calcium pyrophosphate dehydrate (CPPD) or hydroxyapatite (HA) crystal deposition disease can manifest in any joint and when it comprises the cervical spine can lead to pain. Crowned dens syndrome is a rare clinical condition that is featured by crown-like calcification of ligaments around the odontoid process. We describe the case of a 70-year-old man with cervical pain, headache and fever for over a week in whom a neurological condition was suspected. A CT scan revealed lentiform calcifications of the transverse ligament of the atlas. Treatment with steroids and non-steroidal anti-inflammatory improve the symptoms. A proper clinical history and imaging studies avoid unnecessary procedures and can let this entity to be included as a differential diagnosis in acute cervical pain.

Una causa infrecuente de dolor de cuello. Síndrome de la apófisis odontoides coronada / An infrequent cause of neck pain. Crowned dens síndrome

Resumen En la práctica clínica habitual existe un crecimiento en la demanda asistencial de servicios de urgencias. El dolor cervical es una patología muy frecuente que compete a diversos profesionales sanitarios. El síndrome de apófisis odontoides coronada, es una patología muy poco frecuente, que hace parte del espectro de las enfermedades por microcristales de pirofosfato cálcico, ocasionando una calcificación de ligamentos del proceso de odontoides cervical, llevando a una clínica de cervicalgia, fiebre y rigidez de nuca. Esta patología entra en el diagnóstico diferencial con patologías potencialmente graves. En muchas ocasiones lleva a procedimientos y gastos farmacológicos innecesarios, principalmente por el desconocimiento que la transforma en una patología infradiag-nosticada. (Acta Med Colomb 2018; 43: 230-232).

Abstract In the usual clinical practice there is a growth in the demand for emergency services. Cervical pain is a very common pathology that concerns various health professionals. The crowned den syndrome is a very rare pathology, which is part of the spectrum of microcrystalline diseases of calcium pyrophosphate, causing a calcification of ligaments of the cervical odontoid process, leading to clinical signs of neck pain, fever and neck stiffness. This pathology enters into the differential diagnosis with potentially serious pathologies. In many cases it leads to unnecessary pharmacological procedures and expenses, mainly due to the ignorance that turns it into an infra diagnosed pathology. (Acta Med Colomb 2018; 43: 230-232).

Age-Related Prevalence of Periodontoid Calcification and Its Associations with Acute Cervical Pain

STUDY DESIGN: Prospective study. PURPOSE: To assess the prevalence of periodontoid calcification and its associations with acute cervical pain. OVERVIEW OF LITERATURE: Calcium pyrophosphate dihydrate (CPPD) deposition disease is a common rheumatological disorder that occurs especially in elderly patients. Although CPPD crystals induce acute arthritis, these crystals are not usually symptomatic. Calcification surrounding the odontoid process (periodontoid calcification) has been reported to induce inflammation, resulting in acute neck pain. This disease is called crowned dens syndrome. Whether calcification induces inflammation or whether the crystals are symptomatic remains unclear. METHODS: The prevalence of periodontoid calcification at the atlas transverse ligament was examined by computed tomography of the upper cervical spine in patients suspected of brain disease but no cervical pain (control group, n=296), patients with pseudogout of the peripheral joints but no cervical pain (arthritis group, n=41), and patients with acute neck pain (neck pain group, n=22). Next, the correlation between the prevalence of periodontoid calcification and symptoms was analyzed. RESULTS: In the control group, 40 patients (13.5%) showed periodontoid calcification with no significant difference in the prevalence with gender. The prevalence of calcification increased significantly with age (p=0.002). In the arthritis group, 26 patients (63.4%) reported periodontoid calcification. In the neck pain group, 14 patients (63.6%) reported periodontoid calcification. Multiple logistic regression analysis by age and group revealed that higher age, inclusion in the arthritis group, and inclusion in the neck pain group significantly affected the prevalence of calcification. CONCLUSIONS: Our results cumulatively suggest that periodontoid calcification is an aging-related reaction and that calcification per se does not always cause neck pain. Periodontoid calcification was observed more frequently in patients with pseudogout of the peripheral joints and in those with acute neck pain than in asymptomatic control patients.

Calcium pyrophosphate dihydrate deposition disease in the temporomandibular joint: diagnosis and treatment / 대한악안면성형재건외과학회지

BACKGROUND: Calcium pyrophosphate dihydrate deposition disease (CPDD) is a rare disease in the temporomandibular joint (TMJ) space. It forms a calcified crystal mass and induces a limitation of joint movement. CASE PRESENTATION: The calcified mass in our case was occupied in the left TMJ area and extended to the infratemporal and middle cranial fossa. For a complete excision of this mass, we performed a vertical ramus osteotomy and resected the mass around the mandibular condyle. The calcified mass in the infratemporal fossa was carefully excised, and the segmented mandible was anatomically repositioned. Scanning electronic microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) microanalysis was performed to evaluate the calcified mass. The result of SEM/EDS showed that the crystal mass was completely composed of calcium pyrophosphate dihydrate. This result strongly suggested that the calcified mass was CPDD in the TMJ area. CONCLUSIONS: CPDD in the TMJ is a rare disease and is difficult to differentially diagnose from other neoplasms. A histological examination and quantitative microanalysis are required to confirm the diagnosis. In our patient, CPDD in the TMJ was successfully removed via the extracorporeal approach. SEM/EDS microanalysis was used for the differential diagnosis.

Revisión sistemática de la literatura sobre el tratamiento con colchicina en pacientes adultos con osteoartritis de rodilla / Colchicine treatment in adult patients with knee osteoarthritis: Systematic review of the literature

Resumen Contexto: En la práctica clínica de muchos reumatólogos y en algunos ensayos clínicos se ha usado colchicina en pacientes con osteoartritis primaria. A pesar de ello, su papel en el tratamiento de la misma no está claro y las guías no establecen recomendaciones al respecto. Objetivos: Evaluar la eficacia y la seguridad del tratamiento con colchicina en pacientes adultos con osteoartritis de rodilla, tanto primaria como asociada al depósito de cristales de pirofosfato cálcico. Métodos: Se llevó a cabo una búsqueda estructurada de la literatura utilizando las bases de datos Pubmed, Embase, Cochrane Controlled Trials Register y LILACS. Se incluyeron ensayos clínicos controlados, aleatorizados, en donde se haya usado colchicina como intervención en pacientes adultos con osteoartritis de rodilla, primaria o relacionada con pirofosfato de calcio. Resultados: Se incluyeron 5 ensayos clínicos controlados. Se observó una tendencia común en todos los estimados puntuales de los artículos a favorecer el uso de la colchicina para la mejoría del dolor y de la funcionalidad. Se observó una mayor tendencia de efectos adversos gastrointestinales con el uso de la colchicina, sin embargo, el efecto no fue estadísticamente significativo en los estudios individuales. Ninguno de los estudios evaluó calidad de vida. Conclusiones: La colchicina parece ser una alternativa eficaz y segura para el tratamiento de pacientes adultos con osteoartritis de rodilla, tanto primaria como asociada al depósito de cristales de pirofosfato de calcio. Su uso reduce el dolor y mejora la funcionalidad, aunque puede producir síntomas gastrointestinales en algunos pacientes.

Abstract Background: Colchicine is often used in patients with osteoarthritis in which calcium pyrophosphate crystal deposition disease is suspected. Colchicine has also been used by many rheumatologists in clinical practice, and in some trials, on patients with primary osteoarthritis (apparently unrelated to calcium pyrophosphate). However, its role in the treatment of primary osteoarthritis is not clear, and international guidelines have not established recommendations. Objective: To evaluate the efficacy and safety of colchicine for the treatment of adult patients with primary knee osteoarthritis as well as the form associated with calcium pyrophosphate. Methods: A structured literature search was conducted using the PubMed, Embase, Cochrane Controlled Trials Register, and LILACS databases. Randomised controlled trials were included in which colchicine was used as intervention in patients with primary or pyrophosphate calcium-associated knee osteoarthritis. Results: The study included 5 randomised controlled trials, all of which showed a common trend in all estimated points of the joint, favouring the use of colchicine for improvement in pain and functionality. Although the effect was not statistically significant in individual studies, there was a greater tendency of gastrointestinal adverse effects with the use of colchicine. None of the studies assessed quality of life. Conclusions: Colchicine appears to be an effective and safe alternative for treatment of adult patients with knee osteoarthritis, either primary or associated with the deposit of calcium pyrophosphate crystals. Its use reduces pain and improves functionality, but it can cause gastrointestinal symptoms in some patients.

Condrocalcinosis axial: reporte de un caso / Axial chondrocalcinosis: a case report

La artropatía por pirofosfato de calcio (CPPD) se caracteriza por la acumulación de cristales de pirofosfato de calcio en el tejido articular y periarticular. La localización más frecuente son rodillas, muñecas y pelvis. Sin embargo, también existen reportes aislados de compromiso de columna. Se presenta el caso de un paciente varón de 52 años, con antecedentes de doble prótesis de caderas por coxartrosis diagnosticada a los 20 años de edad. Es evaluado en reumatología en febrero de 2017, por cuadro de poliartralgias de grandes articula-ciones, asociada a dolor de columna cervical, dorsal y lumbar. Se realizan exámenes imagenológicos que demuestran la presencia de calcificaciones interdiscales con sobrecrecimiento óseo, secundario a artrosis severa y discreta este-nosis raquídea solo en segmentos lumbares bajos.

The Calcium pyrophosphate dihydrate (CPPD) deposition disease is characterised by the deposition of crystals of CPPD in the articular as well as in periarticular structures. The most frequent location are knees, wrist and pelvis. However, also there are iso-lated cases involving the spine. It presents the case of a 52 years male patient, with history of bone arthrosis dou-ble hips prosthesis by bone arthrosis diagnosed 30 years ago. He is evaluated in feb-ruary 2017 by pain of large joints associated cervical spine pain dorsal and lumbar. Imagenological tests are prerfomed and confirms the presence of intervertebral discs calcifications and bone overgrowth secundary to severe osteoarthrosis and spinal ste-nosis in lower lumbar segments.

Acute Pseudogout of the Neck: "Crowned Dens" Revisited

Calcium pyrophosphate dihydrate crystal deposition disease is associated with an acute mono- or pauciarthritis, termed "pseudogout" in elderly patients, involving a large joint (including the knees, ankles) or a chronic arthropathy manifesting as mild joint pain and stiffness. Pseudogout is a crystal-deposition disease of peripheral joints, usually encountered in elderly patients. However, acute presentation of pseudogout around the odontoid process comprises a "crowned-dens" appearance, and requires contemplation of differential diagnoses. We recently experienced a case of pseudogout in the cervical spine presenting with fever and acute neck pain that was successfully treated with a colchicine and low-dose oral steroid. We reported this case with a review of the relevant literature.

A Case of Acute Calcium Pyrophosphate Crystal Arthritis in the Lumbar Facet Joint

Calcium pyrophosphate dihydrate deposition disease most commonly presents with acute arthritis of the peripheral joints. Infrequently, a mass effect of this disease can cause axial symptoms, such as spinal stenosis, radiculopathy, or myelopathy. Herein, we report on the first Korean case of acute arthritis in the lumbar facet joint due to calcium pyrophosphate dihydrate crystal deposition disease. A 73-year-old female presented with acute fever, severe lumbago, and knee arthralgia, 11 days after partial parathyroidectomy. Plain radiographs showed multiple chondrocalcinosis, while a bone scan, computed tomography, and magnetic resonance imaging showed right L5-S1 facet arthritis. In synovial fluid from the facet and knee joints, positively birefringent calcium pyrophosphate dihydrate crystals were observed under polarized light microscopy. Under the diagnosis of acute calcium pyrophosphate dihydrate crystal arthritis (formerly known as 'pseudogout') in the facet joint, an intra-articular triamcinolone injection was administered, which resulted in dramatic improvement of the symptoms within 24 hours.

Gitelman's Syndrome Associated with Chondrocalcinosis

Gitelman's syndrome (GS), a hereditary disease characterized by hypokalemia, hypomagnesemia, and hypocalciuria, is a salt-losing renal tubulopathy. Herein, we describe a case of a 28-year-old woman diagnosed with atypical GS accompanying chondrocalcinosis. One year ago, she presented with vomiting, hypokalemic metabolic alkalosis, and hypocalciuria, and was tested by diuretic challenge test. As a result, she was diagnosed with atypical GS with normomagnesemia and treated with spironolactone and potassium supplementation. Meanwhile, acute arthritis of the right 1st metatarsophalangeal joint occurred. On the radiographies of the knees, chondrocalcinosis was observed. To the best of our knowledge, this is the first report in Korea of GS with chondrocalcinosis. Antialdosterone therapy or magnesium supplementation is effective in preventing the progression of chondrocalcinosis; thus, early diagnosis and treatment of GS are important.

Enfermedad por depósito de cristales de pirofosfato de calcio como ejemplo de forma de manifestación de la enfermedad en el adulto mayor / Calcium pyrophosphate dihydrate crystal deposition disease as an example of illness presentation in the elderly

Illness presentation in the elderly may be entirely non-specific, with fatigue, loss of function or the presence of geriatric syndromes. We report a 90 years old male consulting in the emergency room for delirium that persisted throughout hospitalization without finding a cause. During the course of hospitalization mild fever appeared and a left knee swelling became apparent. A synovial fluid aspiration showed a leukocyte count of 360 per field with 60% polymorphonuclear cells. The culture was negative. With a presumptive diagnosis of pseudogout, cochicine and celecoxib were started with remission of the confusional state. The patient was discharged 13 days after admission in good conditions.

Pseudogout: A Rare Cause of Acute Arthritis Following Arthroscopic Anterior Cruciate Ligament Reconstruction

We report a case of an acute pseudogout attack following single-bundle anterior cruciate ligament (ACL) reconstruction in a 35-year-old man. At the initial reconstruction surgery, he was found to have early degenerative changes mainly in the lateral compartment. He presented with acute onset pain and swelling following reconstruction of the ACL. Arthroscopic irrigation was performed and the synovial fluid was positive for calcium pyrophosphate crystals. A pseudogout attack must be considered in the differential diagnosis in cases of acute onset pain and swelling after arthroscopic surgery, especially with the background of degenerative knee changes, and this may signify a poorer long-term outcome.

Ultrasonographic Assessment in Crystal-induced Arthritis / 대한내과학회지

The latest recommendations for the diagnosis and management of crystal-induced arthritis, such as gout and calcium pyrophosphate dihydrate (CPPD) deposition disease, recognize the diagnostic potential of musculoskeletal ultrasonography (MSUS). MSUS allows rapid, highly sensitive, non-invasive detection of microcrystal aggregates in multiple anatomic areas, and can be used as a safe, reliable guide for aspiration of articular and periarticular specimens suitable for microscopic analysis. MSUS can also be used to monitor disease after treatment. Ultrasonographic differentiation between gout and CPPD deposition disease is based on the characteristics of crystal aggregates and their preferential localization in different anatomical areas. This rapid assessment may profoundly affect the clinical process, avoiding expensive, time-consuming diagnostic procedures. This article reviews the current status of and recent advances in MSUS imaging in crystal-induced arthritis.

Gammapatía monoclonal de significado incierto A propósito de un caso de nefropatía por depósito de cadenas ligeras lambda / Monoclonal gammopathy of undetermined significance Apropos of a case of lambda light chain deposition nephropathy

La nefropatía asociada a las gammapatías monoclonales es debida principalmente al depósito de cadenas ligeras. Las enfermedades renales paraproteinémicas son lesiones asociadas con depósito de inmunoglobulinas intactas o fragmentos de inmunoglobulinas (cadenas pesadas y cadenas ligeras). La enfermedad por depósito de cadenas ligeras es una condición rara, caracterizada por el depósito de cadenas ligeras monoclonales en muchos órganos y a nivel renal predominantemente en glomérulos y membranas basales tubulares. La enfermedad está frecuentemente asociada con desórdenes linfoproliferativos, y la mayoría de casos son causados por depósito de cadenas ligeras kappa. Aunque se presenta sobre todo en cuadros malignos, en ocasiones no se detecta patología hematológica y se denomina idiopática o "primaria". Suele manifestarse como una insuficiencia renal severa con proteinuria nefrótica, no tiene tratamiento claramente establecido y el pronóstico es malo. Se describen las características clínicas e histológicas del segundo caso informado en Colombia de nefropatía por depósito de cadenas ligeras diagnosticado en el contexto de una enfermedad renal paraproteinémica sin datos de malignidad. (Acta Med Colomb 2014; 39: 196-201).

Nephropathy associated with monoclonal gammopathies is mainly due to light chain deposition. The paraproteinemic kidney diseases are lesions associated with deposition of intact immunoglobulins or fragments of immunoglobulins (heavy and light chains). The disease due to deposition of light chains is a rare condition characterized by deposition of monoclonal light chains in many organs and as for the kidney, predominantly in glomeruli and tubular basement membranes. The disease is frequently associated with lymphoproliferative disorders and the majority of cases are caused by deposition of kappa light chains. Although presented primarily in clinical pictures of malignancy, sometimes no hematological pathology is detected and is called idiopathic or "primary". It usually manifests as severe renal failure with nephrotic proteinuria, has not a clearly established treatment and the prognosis is poor. The clinical and histological features of the second case reported in Colombia of a light chain deposition nephropathy diagnosed in the context of a kidney paraproteinemic disease without malignancy data, is presented. (Acta Med Colomb 2014; 39: 196-201).

A Case of Calcium Pyrophosphate Dihydrate Deposition Disease Associated with Primary Hyperparathyroidism

Calcium pyrophosphate dihydrate (CPPD) deposition disease is a heterogeneous group of diseases with CPPD crystal deposition. Aging is the most common risk factor for CPPD deposition, followed by osteoarthritis and previous injury. Occasionally, CPPD depositions are associated with familial predisposition and metabolic diseases, including hemochromatosis, primary hyperparathyroidism, hypophosphatasia, and hypomagnesemia. CPPD deposition diseases associated with primary hyperparathyroidism in Koreans have rarely been reported. Thus, we report a case of a relatively young female patient with CPPD deposition disease associated with primary hyperparathyroidism, which was diagnosed through a polarized microscopic examination of the synovial fluid and a subtotal parathyroidectomy.

Pseudogout of the Knee after Intraarticular Injection of Hyaluronic Acid / 대한정형외과학회잡지

An 82-year-old woman underwent surgery for the left intertrochanteric fracture. However, during hospitalization, she complained of pain on the right knee. Radiographs showed moderately degenerative arthritis and intrameniscal calcification. Hyaluronic acid was administered by intraarticular injection. After injection, arthritic symptoms improved. Five days after injection, she complained of severe pain, swelling, and heating sensation in the right knee with chills and fever. Blood test showed elevated white blood cell (WBC) count and C-reactive protein. WBC in synovial fluid increased to 47,250/mm3. Antimicrobial therapy was administered under the impression of acute pyogenic arthritis by adverse reaction of hyaluronic acid injection. Polarization microscope showed calcium pyrophosphate dihydrate crystals. Synovial fluid culture was negative. Finally, she was diagnosed as pseudogout. The symptoms improved within one week. To our knowledge, there has been no report of pseudogout following intraarticular injection of hyaluronic acid in Korea. Therefore, we report this case with a review of the literature.

Laboratory Findings in the Patients with Arthritis / 대한내과학회지

Arthritis is caused by various diseases including rheumatoid arthritis (RA), osteoarthritis, gout and trauma, and joint involvement also occurs in some autoimmune diseases, such as systemic lupus erythematosus and Sjogren's syndrome. Some laboratory tests provide useful information in both diagnosis and prognosis. RF and anti-CCP (cyclic citrullinated peptide) antibody are detected in approximately 70-80% of patients with RA, and often associated with a worse prognosis (e.g., bony erosion and joint deformity). Acute phase reactants, such as erythrocyte sedimentation rate and C-reactive protein, parallel the activity of RA, and their persistent elevation are also associated with a poor prognosis. Crystal examination in synovial fluid is essential to confirm the diagnosis of gout and pseudogout, and the synovial fluid culture is also important in septic arthritis. Anti-nuclear antibody helps to distinguish non-immune arthritis from systemic rheumatic diseases. However, arthritis cannot be diagnosed only with laboratory findings, and physician should consider comprehensive physical examination, clinical findings, and imaging findings as well as laboratory findings. In this topic review, laboratory tests useful for diagnosis of arthritis will be discussed and summarized.