Correspondence: Knee Effusion with Peripheral Eosinophilia: A Need to Rule out Idiopathic Eosinophilic Synovitis RL01-RL02
Dr. Sharat Agarwal,
B-10A, Faculty Quarters, NEIGRIHMS, Mawdiangdiang, Shillong, Meghalaya, India.
At the outset, I would like to congratulate the authors of the article entitled-‘Knee Effusion with Peripheral Eosinophilia: A Need to Rule out Idiopathic Eosinophilic Synovitis’ published in JCDR (1). However, I regret to mention that the workup mentioned in this article is highly inadequate, before one can come to a definitive diagnosis of eosinophilic synovitis.
I would like to highlight that it is very crucial to rule out history of ‘milk allergy’, which has been ascertained by finding increased IgG anti milk levels, IgG milk-circulating immune complexes and in vitro T-cell sensitivity to milk as mentioned in the literature (2).
It is must to undertake skin testing for commonly available allergens related to eosinophilia (house dust, Acaridae, feathers, kapok upholstery, ragweed, trees, grasses, pollens, weeds, dog and cat hair, Alternaria, Horrnodendrum). Laboratory testing has to include, in addition to what was undertaken by the author, blood chemistry profile; circulating IgG, IgA, IgM, and IgE; VDRL; antistreptolysin 0 (ASO); with subspecificity assays for antibodies to native DNA (anti-nDNA), Sm, RNP, SS-Pi, SS-B, Scl-70, PM-1, centromere, nucleole; and organ-specific autoantibodies (3).
Also, nephelometric assays of C3 and C4; microbiology studies of blood and stool samples for parasites especially Taenia solium as Indian subcontinent is endemic for this infection; serology for HBV and HCV should be included (4).
Minor eosinophilia, in the range of 1-10%, can occasionally be found in haemorrhagic fluids and in the presence of systemic diseases, such as rheumatoid arthritis, rheumatic fever, hypereosinophilic syndrome, parasitic disease and probably many others.
Eosinophilic synovitis has been found in patients with systemic and local parasitic infections, in cancer patients with articular and extraarticular cancerous involvement who received previous radiotherapy and/or chemotherapy, and in patients submitted to air or contrast knee arthrography.
In the existing clinical scenario, it is must to rule out low grade septic (pyogenic) arthritis, tubercular arthritis and Juvenile Monoarticular Synovitis (JRA) before finally labelling this condition; so, this essentially warrants the synovial histopathological confirmation (6).
Moreover, it is very important to rule out ‘gout’, the incidence of which is increasing even though we may agree that the patient was a teenager as various hereditary enzyme linked hyperuricaemic conditions can cause early age hyperuricemia (6).
Finally, it is must to document ‘eosinophilic infiltration of synovium”, which has to be confirmed with Fine Needle Aspiration Cytology (FNAC) or arthroscopic and open biopsy, before coming to a conclusion. Besides, the elevated levels and assessment of IgE in synovial fluid has not been undertaken in this particular case (7).
As far as management of this condition is concerned, it is better to avoid the use of ‘Aspirin’ as it causes ‘Widal Syndrome’ (8) and also Ibuprofen (9). They have the potential to cause eosinophilia; the author has managed the condition with ‘Ibuprofen’.
Last is the issue regarding the follow-up of such patients. It is well mentioned in the literature and an established dictum that “Eosinophilic disorders are chronic conditions that require long term treatment for the prevention of clinical manifestations. Morbidity and mortality for many eosinophilic disorders remain high, so they need constant regular monitoring even after initial remission” (10).