Evaluation of etiology, clinical and laboratory data of childhood arthritis

Aim: The aim of the present study was to evaluate the etiologies, diagnostic approach, clinical and laboratory data of patients with arthritis in a Turkish tertiary care hospital in children. Material and Methods: 306 hospitalized children aged between 7 months-18 years, diagnosed with arthritis were included in the study between 2008 – 2013. The medical records of patients were reviewed retrospectively. Results: Of the patients, 51.6% were female, 48.4% were male. The average age was 118 months. Arthritis was symmetrical type in 29.4% of patients and asymmetrical type in 70.6%. The diagnoses of patients were Acute Rheumatic Fever/ Poststreptococcal reactive arthritis (ARF/PSRA) (39.2%), Collagen Tissue Disorders (CTD) (29%), Brucellar arthritis (13.4%), reactive arthritis (12.5%), septic arthritis (5.2%) and arthritis secondary to malignancy (0.7%), respectively. Of the patients with CTD; Juvenil idiopathic arthritis (JIA) was the most common in frequency (66.3%). Patellar joint involvement was the most common in frequency (62.4%). The mean ASO levels was significantly higher in patients with ARF/PSRA group [p=0.000]. Average leucocyte count of ARF/PSRA group was significantly higher than CTD group [p=0.000]. Average neutrophil percentage was significantly higher in ARF/PSRA group than brucellar arthritis group [p=0.000]. The mean duration of diagnosis and therapy was found to be significantly longer in patients with CTD [p=0.000]. All patients were cured except one patient with brucellar arthritis. Conclusion: Arthritis can be a manifestation of multiple disease processes in children. Therefore, the clinician must consider a broad differential diagnosis. Detail history and physical examination with a clinical follow-up in addition to useful laboratory testing may help to establish the cause of arthritis in children.


Introduction
Arthritis is simply defined as inflammation of a joint that may affect one or more joints and often is accompanied by swelling, tenderness and pain with movement. The pathophysiology of this inflammatory process varies depending on the underlying cause [1].
Frequent clinical examination for potential diagnostic clues, timely use and interpretation of laboratory or imaging tools are crucial for the diagnosis and early treatment of patients with arthritis [2]. The aim of the present study was to evaluate the etiologies, diagnostic approach, clinical and laboratory data of patients with arthritis in a Turkish tertiary care teaching hospital in children.

Material and Methods
We reviewed the medical records of children who were admitted to the pediatric clinic with a diagnosis of arthritis. An arthritis which lasts longer than 6 weeks, is defined as chronic arthritis. Monoarthritis is the inflammation which is limited to one joint. Oligoarthritis is defined as the arthritis which includes fewer than five joints. Polyarthritisis is defined as the arthritis includes five or more joints. Active substance growth and bacterial appearance by gram staining in the synovial fluid culture or observing purulent fluid during synovial fluid aspiration was considered as septic arthritis [2,3].
The criteria recommended by Ayoub were used for the diagnosis of post-streptococcal reactive arthritis [PSRA] and reactive post-infectious arthritis was classified as arthritis, which lasts 6 weeks and is not associated with an infection [4] Prevalence for any musculoskeletal problem was known significantly higher in males than females in worldwide. It was also concluded that infectious arthritis was more common in males and toxic synovitis was more common in females [9].
Autoimmune diseases are more common in females, probably for the different hormonal levels, being estrogens strongly implicated in the development of autoimmunity [10]. In our study we found no difference in groups regarding diagnosis distribution according to gender.
The causes of arthritis in our study were ARF, CTD, brucellar arthritis, reactive arthritis and malignancy in descending frequency. In literature, toxic synovitis is stated to be the most common arthritis etiology in outpatients [9,10]. We conducted our study in patients who were hospitalized so that we excluded toxic synovitis patients. ARF may have different clinical manifestations in different countries according to genetic predisposition, prevalence of rheumatogenic strains, social and economic conditions. There are also differences in the prevalence of Jones criteria on different continents which may be explained by epitopes of rheumatogenic streptococcal strains and genetics. The estimated incidence rate of acute rheumatic fever was 7.4/100,000 in the Central Anatolia region [11,12]. PSRA is defined as arthritis in one or more joints in a patient who does not fulfill the Jones criteria for a diagnosis of ARF. Some authors consider PSRA as part of the spectrum of ARF, while other authors consider it as a different entity [13].
The most common cause of arthritis was ARF/PSRA in our study and its frequency was approximately 40%. This frequency is much higher than the values given in the literature. We think that the reason for this finding is the existence of a 3rd level children's cardiology clinic in our hospital which many patients were referred from the surrounding cities.
The second common cause of arthritis in our study was CTDs.
Approximately 70% of this group had JIA and 17% had FMF. Similar studies in the literature also stated that JIA was the most common disease in CTD category [14]. Since FMF is a prevalent disease in our country, its high frequency was an expected result [15].  can be confused with other disorders due to the indefinite complaints like fever, arthritis, back pain, and weakness.
Therefore, especially in the countries where brucellosis is common, fever accompanied by hip and lumbar pain should be important in the differential diagnosis [16,17]. We diagnosed brucella arthritis in 13.4% of the cases in our study and it may be due to high suspicion of infection. of the patients [9]. We think that the microbiological etiology of classical reactive arthritis would get varied with investigations that allow fast and detailed microbiological examination. In our study 3 of the patients were diagnosed with septic arthritis secondary to trauma, 1 was diagnosed with tuberculosis arthritis and 2 were diagnosed with septic arthritis due to S.aureus.
Arthritis affected the large joints mostly the knee joints as in the literature in our study [2,9]. There is overlap between causes of monoarticular and polyarticular pain and swelling.

Conclusion
Arthritis can be a manifestation of systemic disease processes in children. Appropriate diagnosis and management of pediatric arthritis can facilitate prompt recovery and prevent debilitating consequences. Therefore, the clinician must consider a broad differential diagnosis, keeping a high degree of suspicion for diseases that may have serious consequence. Complete and thorough history and physical examination in addition to clinical follow-up and diagnostic clues in laboratory may help to brighten the etiology of arthritis in childhood.