Defence of doctoral thesis on factors influencing development of temporomandibular joint arthritis in children with juvenile idiopathic arthritis

On 5 March 2018 at 15:00 in an open meeting of the Rīga Stradiņš University (RSU) Medical Promotion Council to be held in the Hippocrates Lecture Theatre (16 Dzirciema Street, Riga) Zane Dāvidsone will defend her doctoral thesis “Temporomandibular joint arthritis development influencing factors, clinical and radiologic symptoms in children with juvenile idiopathic arthritis”.

Children with juvenile idiopathic arthritis (chronic joint inflammation) are frequently also affected by temporomandibular joint (temporal and lower jaw joint) arthritis. Previous studies show that often there are no obvious symptoms of arthritis in these joints, making diagnosis difficult, whereas the potential consequences of untreated arthritis may interfere with normal dentofacial development, expressed as pathologic dental occlusion, micrognathia (undersized jaw), restricted mouth opening or functional problems, at times making it difficult to chew and even speak.

To prevent possible irreversible damage, early diagnosis is vital for establishing further therapy options aimed at the reduction of the inflammation. The gold standard of diagnosis of joint damage is magnetic resonance imaging (MRI) which is not possible for all children with juvenile idiopathic arthritis at different stages of the disease. Therefore, it is necessary to identify the group of patients with higher risk for temporomandibular joint arthritis.

The purpose of the study was to identify the factors affecting occurrence of temporomandibular joint inflammation and the correlation of the different patient’s subjective and objective symptoms with MRI findings. The author has analysed demographic, disease characteristic clinical, laboratory and HLA II allele genotyping data in patient groups with no signs of inflammation and with signs of inflammation on MRI.

The study has revealed that temporomandibular joint arthritis is more frequent in JIA patients with increased level of C-Reactive protein (marker of inflammation in the blood). Certain HLA II class alleles are associated with a higher arthritis risk in the said joints, while others have a protective influence. In the result of the assessment of the subjective and objective temporomandibular joint inflammation symptoms, it has been established that statistically more symptoms are found in the patient group with a combination of active and chronic inflammation detected on MRI. The analysis of logical regression showed that the increase in the number of objective symptoms by 1 increases the probability of positive MRI findings 2, 3 times. In patients without symptoms, MRI is most often without pathological changes.

The outcomes of the study will help decide which patients need MRI investigation to enable possibly early diagnosis of arthritis and start proper treatment. HLA II allele genotyping results provide a major contribution to understanding the pathogenesis of JIA and could be used for diagnosis in the future.