Dr. Augustus Roi Felty first described Felty’s syndrome in 1924. This autoimmune disease is characterized by a triad of rheumatoid arthritis, splenomegaly (abnormally enlarged spleen) and neutropenia (deficiency of neutrophils = reduced number of white blood cells). The syndrome has a wide range of symptoms that are never all present at the same time. Patients with this syndrome are at risk for infections because they have low white blood cell counts. The syndrome is rare, which means that almost no scientifically substantiated information can be found and few case reports are available. This makes Felty’s syndrome difficult to treat.
- What is Felty’s Syndrome?
- Epidemiology Felty syndrome
- Causes and heredity of the condition
- Symptoms: Joints (rheumatoid arthritis), blood (neutropenia) and spleen (splenomegaly)
- Diagnosis and examinations
- Treatment of condition
- Prevention Felty Syndrome
- Prognosis
What is Felty’s Syndrome?
The production of white blood cells takes place in the bone marrow. Bone marrow function is not affected in patients with Felty’s syndrome. However, excessive storage of white blood cells occurs in the patient’s spleen. This mainly occurs in patients who have antibodies against a certain type of white blood cells that are usually affected (granulocytes and neutrophils). The Arthritis Organization of Canada claims that white blood cell development is sometimes abnormal in the bone marrow. A third possibility is that the immune system destroys the white blood cells. Patients with this syndrome are at risk of infections because they have a reduced number of white blood cells.
Epidemiology Felty syndrome
Felty Syndrome affects approximately 1-3% of all patients with rheumatoid arthritis (chronic autoimmune disease involving inflammation of joints and other organs) and rheumatoid arthritis occurs in approximately 1% of the population. It is more common in patients who have had rheumatoid arthritis for more than ten years. Felty’s syndrome is associated with the HLA-DR4 genotype. This genotype is a marker for more aggressive rheumatoid arthritis with more extra-articular symptoms. The syndrome is rare in children. In addition, patients with black skin color are rarely affected. The true prevalence of Felty Syndrome is difficult to determine because many affected patients are asymptomatic. The incidence is likely to decrease when more powerful antirheumatic agents come onto the market. The Felty Syndrome is also most common in people in their thirties to seventies. Felty Syndrome is approximately three times more common in women, but under-reporting and asymptomatic cases make the exact ratio difficult to determine.
Causes and heredity of the condition
Etiology
The cause of Felty’s syndrome is unknown. It is more common in people with extra-articular symptoms of rheumatoid arthritis. Although this group is at greater risk of developing the syndrome, it is not the cause of the condition. Some patients have Human Leucocytic Antigen (HLA-DR4) in their serum.
Heredity
Some cases of Felty Syndrome may be genetic. Further scientific research is still required.
Symptoms: Joints (rheumatoid arthritis), blood (neutropenia) and spleen (splenomegaly)
Felty’s syndrome is diagnosed by the presence of three primary symptoms: rheumatoid arthritis, splenomegaly (enlarged spleen), and neutropenia (medical term for “abnormally low white blood cell count”).
Blood
Neutropenia (decreased neutrophil (white blood cell) counts), the main symptom of Felty Syndrome, results in a higher incidence of bacterial infections (usually occurring on the skin, in the mouth, and in the upper and lower respiratory tract). In rare cases, the doctor discovers Felty Syndrome due to neutropenia in an RA patient.
Joints
Felty Syndrome differs from rheumatoid arthritis by having more severe arthritis and extra-articular symptoms.
Spleen
The patient suffers from splenomegaly; in other words, the spleen is enlarged (larger than normal).
Chest pain occurs in Felty’s syndrome / Source: Pexels, Pixabay
Additional symptoms
Other extra-articular symptoms of Felty Syndrome include:
- anorexia,
- leg ulcers,
- pallor
- anemia,
- upper left abdominal pain (due to splenomegaly or splenic infarctions),
- weight loss,
- hepatomegaly (enlargement of the liver)
- skin hyperpigmentation (usually on the extensor part of the lower leg),
- ischemia of the extremities (lack of blood flow)
- pulmonary fibrosis (scarring of lungs with shortness of breath),
- lymphadenopathy (swollen lymph nodes),
- neuropathy,
- eye symptoms:
- dry eyes and irritation due to Sjögren’s syndrome,
- red eyes and sore eyes (eye pain) due to episcleritis: inflammation of the connective tissue between sclera (hard sclera) and conjunctiva (eye conjunctiva)
- peripheral neuropathy (damage to peripheral nerves with pain, weakness, numbness and tingling especially in the hands and feet),
- pleurisy (pleurisy with chest pain),
- symptoms related to rheumatoid arthritis, including swelling, pain, stiffness, lumps and deformities,
- recurrent infections due to neutropenia (lung infections and skin infections are most common),
- vasculitis (blood vessel inflammation) and
- fatigue.
Felty Syndrome is linked to other autoimmune diseases such as Sjögren’s syndrome, Systemic lupus erythematosus (SLE) and vasculitis.
Diagnosis and examinations
There are no specific diagnostic criteria for Felty’s syndrome. The diagnosis is made clinically in patients with rheumatoid arthritis with unexplained neutropenia and splenomegaly. The doctor also looks at the patient’s history in detail. The doctor usually first performs a physical examination. He identifies a swollen liver (hepatomegaly), spleen (splenomegaly) or lymph nodes (lymphadenopathy). The patient’s joints may also show symptoms of rheumatoid arthritis such as swelling, redness and warmth.
Differential diagnosis
The differential diagnoses include cirrhosis, a myeloproliferative disease, non-Hodgkin lymphoma (cancer in lymphocytes of the immune system with enlarged lymph nodes and general symptoms), sarcoidosis, Sjögren’s syndrome, Systemic lupus erythematosus (SLE) and tuberculosis.
Diagnostic tests
Relevant tests are:
Blood tests
An extensive blood test is necessary.
- Autoantibodies – rheumatoid factor and anti-CCP antibody.
- Possible increased liver values if the liver is affected.
- Possibly increased inflammatory markers (ESR and CRP) (*).
- Complete blood test for determining neutropenia ± anemia of chronic diseases.
For your information (*)
- ESR: Red blood cell sedimentation rate: rate at which red blood cells settle in a glass bowl filled with non-clotted blood (the higher the sedimentation rate; the more inflammation is present in the body)
- CRP: C-Reactive Protein: a protein that the liver produces in response to inflammation; this increases with an infection.
Radiology
Abdominal ultrasound (ultrasound examination) or CT scan to evaluate splenomegaly.
Bone marrow biopsy
A bone marrow biopsy is necessary to rule out hematological disorders such as non-Hodgkin lymphoma.
Treatment of condition
Felty’s syndrome is an immune disease. The treatment of the syndrome is symptomatic and supportive. The doctor treats the underlying rheumatoid arthritis. Immunosuppressive therapy for RA often improves granulocytopenia and splenomegaly; Most of the traditional medications that the doctor uses to treat RA are also used to treat Felty’s syndrome. Good randomized, controlled trials of other drugs have not yet been conducted in Felty’s syndrome. Most reports on treatments concern small numbers of patients.
Patients with serious infections receive weekly injections of a stimulating factor (granulocyte stimulating factor / GSF) to increase the number of white blood cells.
In critically ill patients, splenectomy (surgical removal of the spleen) improves neutropenia. But little information has been found in the medical literature about the long-term effects of this procedure.
Prevention Felty Syndrome
Maintaining good health is important to prevent complications and infections. This is reflected in wearing protective clothing, washing hands thoroughly, not coming into contact with patients who have (recently) had a cold or the flu, …
Prognosis
In general, patients with Felty’s syndrome have a worse prognosis than those with uncomplicated rheumatoid arthritis. They have increased morbidity and mortality from infections and complications. Since Felty Syndrome is rare, scientifically sound information is based on small studies and only few research reports are available.
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