61- year-old female school teacher, experiencing pain and early morning stiffness for the past 6 years

Discussion of the case

The 61-year-old, female patient had long-standing RA of 6 years duration and was on alternative therapy for the past 5 years and intermittent NSAIDs. She had severe dry mouth/eyes, significant weight loss, reduced appetite, and back pain. She had persistent dry cough, but chest X-ray was normal.  The patient was immobile with minimal swelling and pain. History wise patient can be considered to have Rheumatoid arthritis, Systemic lupus erythematosus, Sjogren’s syndrome, malignancy associated rheumatic disease. But to considered the malignancy associated rheumatic disease duration of 6 months is too long. The weight loss though may be an indicator towards it, but duration is too long to consider the diagnosis.   Her investigation revealed normal Hb%, significant leukopenia with absolute granulocyte count (AGC) less than 600 cell/ cu mm.  Her platelet count and the levels of alkaline phosphatase, liver enzymes, vitamin B12 and folic acid were normal. She had significantly elevated ESR and CRP levels. Serum albumin and vit D3 were below normal. Her ANA was negative.

The possible differential diagnoses are: Felty syndrome (a variant of RA), SLE, Sjogren's syndrome, large granulocyte lymphocyte (LGL) syndrome, and isolated autoimmune neutropenia. Comparison of the clinical features of possible differential diagnoses is listed in table 1.

Table 1: Comparison of the clinical features of possible differential diagnoses

The patient was initially treated for deforming polyarthritis. She was on alternative treatment, but not on any of the DMARDs. Negative ANA, elevated CRP, and deforming arthritis rule out the possibility of SLE. The patient had severe dry mouth, suggestive of Sjogren's syndrome. The patient's RF titres were high and ANA was negative. There were erosions in hand X-ray and clinical features suggestive of RA. These findings indicate the probability of developing Sjogren's syndrome, secondary to RA. The peripheral smear was not suggestive of large granular lymphocyte. In view of these observations, the diagnosis could be concluded as Felty syndrome.

The patient had vit D deficiency, but no other nutritional deficiency to explain marrow dyserythropoesis. She had no splenomegaly, but it is not essential to conclude the diagnosis of Felty syndrome. Felty syndrome was described in 1924.¹ The incidence of Felty syndrome in RA is lesser in patients using DMARDs earlier in the course of RA. Previous literature shows that the disease occurs at a frequency of 1-3% in RA patients. Such patients need to be managed meticulously and the neutropenic prophylaxis is essential. The patient can be gradually shifted to regular DMARD treatment after the improvement of neutrophil count.

Final diagnosis

Felty syndrome (RA with secondary Sjogren's syndrome)

Follow-up

Patient was initially started with HCQ and low-dose steroid as fungal prophylaxis. Steroid was subsequently reduced and the MTX was escalated to best-tolerated dose. Patient is doing well.

Learning points

• Felty syndrome is a possibility to be considered in RA patients presenting with isolated neutropenia.
• Work-up to exclude other possibilities is required.

Reference

Felty AR. Chronic arthritis in the adult, associated withsplenomegaly and leukopenia: a report of five cases of an-MRF unusual clinical syndrome. Johns Hopkins Med J 1924; 35:16-20.