Antisynthetase Syndrome

What is antisynthetase syndrome?

It is an inflammatory muscle disease that is autoimmune in nature. It is characterized by myositis (inflammation of the muscles), polyarthritis (inflammation of various joints), and Raynaud phenomenon (vasospasm of the fingers and toes secondary to extreme cold).

To correctly diagnose antisynthetase syndrome, there should be serum autoantibodies directed against aminoacyl-tRNA synthetases. These are enzymes which have something to do with protein synthesis. Examples of antisynthetase antibodies are Jo-1, YRS, and Zo. What is anti Jo 1? It is the commonly detected antibody in antisynthetase syndrome. ^{(1, 2)}

What are the causes?

The exact cause of antisynthetase syndrome is still unknown up to this time. From a medical standpoint, it is considered an autoimmune disorder. By definition, autoimmune disease is when the immune system of the body attacks healthy tissues. ⁽²⁾

Image 1: An image of patients with mechanics hands, which is one of the clinical manifestations of antisynthetase syndrome.
Picture Source: www.researchgate.net

Photo 2: A film x-ray of a patient with antisynthetase syndrome
Image Source: www.elsevier.es

Antisynthetase Syndrome Symptoms

What are the clinical manifestations of antisynthetase syndrome? The typical manifestations are fever, myositis (inflammation of the muscles), polyarthritis (inflammation of the joints), interstitial lung disease, and Raynaud phenomenon. About 20% of patients has fever, which usually occur at the onset of the disease. Approximately 90% of patients experience myositis, which is associated with anti Jo 1 antibodies.

There is noticeable muscle weakness, which makes it extremely difficult for you to climb stairs or even get up from a chair. Because of interstitial lung disease, the patient could experience shortness of breath and difficulty swallowing. About 50% of patient experienced inflammatory arthritis.

Reynaud’s phenomenon is also one of the clinical manifestations of antisynthetase syndrome. About 40% of patients experienced Reynaud’s phenomenon. The patient also has thick, cracked skin, usually on the palms or so-called mechanics hands. ^{(1, 2, 3)}

How to diagnose antisynthetase syndrome?

What are the bases for diagnosing antisynthetase antibody syndrome? The doctor will thoroughly assess the condition of the patient paying particular attention to the clinical manifestations. Other similar features should be ruled out too. The doctor will order various laboratory testing and diagnosis to thoroughly assess the condition of the patient. Diagnostic procedures include the following:

• Blood test – This is to evaluate the level of muscle enxymes like aldolase and creatine kinase.
• Other lab test should be performed to check for the presence of autoantibodies such as Electromyography (EMG) and high resolution computed tomography of the lungs (HRCT).
• MRI (magnetic resonance imaging) of the muscles, muscle biopsy, pulmonary function test, and lung biopsy.
• The patient will be evaluated for swallowing difficulty and risk for aspiration. ^{(3, 4, 5)}

Antisynthetase Syndrome Treatment

How to treat antisynthetase syndrome? The drug of choice for symptomatic management of antisynthetase syndrome is glucocorticosteroid. It is for long term used, usually months to years. Initially, a high dose of prednisone is given to the patient for straight six weeks to effectively manage the disease.

After some time, the dosage is tapered slowly over the next few months. This is to prevent remission of the disease. If the antisynthetase syndrome is severe, a methylprednisolone is given via intravenous route for three to five days. ⁽⁵⁾

How long will it take for you to see a significant improvement? When it comes to muscle strength improvement, it usually takes weeks and even months. When a patient is taking steroids, a prophylactic treatment is given in order to avoid steroid-induced osteoporosis and fungal infections. Prior to starting a steroid therapy, the patient should be screened whether or not he needs immunization as a prophylactic treatment.

Aside from corticosteroid, other drugs can also be given to effectively manage the disease. These include Rituximab, Azathioprine, Cyclophosphamide, and Methotrexate. The patient is strongly advised to have physical therapy and rehabilitation. In fact, they should start as soon as the disease is diagnosed in order to prevent muscle weakness and muscle deconditioning. ^{(5, 6, 7)}

Prognosis and Life expectancy

What is the clinical outcome of patients with antisynthetase syndrome? What is antisynthetase syndrome life expectancy and how was it living with antisynthetase syndrome? Fortunately, patients suffering from antisynthetase syndrome respond well to steroids and immunosuppressive agents. Generally speaking, antisynthetase syndrome is a chronic disease that require long term treatment. Who are responsive to treatment? Those patients with antisynthetase syndrome with muscle involvement only. ^{(7, 8)}

However, if the lungs are affected, the patient could have moderately poor prognosis. The overall prognosis primarily depends on the type and severity of lung injury. Usually, those who have poor prognosis are older patients (60 years old and above), those with negative ANA antibody test, and those positive for malignancy. How soon the disease is diagnose can also affect the prognosis. Those patients treated early have a very good prognosis. ^{(8, 10)}

How will it be like living with antisynthetase syndrome?

• You should use protective material when moving – having an antisynthetase syndrome can surely affect your lifestyle. You will be slower than before. It seems like you are being a child again. You might need a cane, walker, splints, and health aides when walking.
• Decreased activity level – You can’t easily move like before, which leads to the decrease of activity level. However, you need to keep moving little by little. There should be alternate period of rest. Learn how to budget your energy. The goal is for you to live comfortably within your illness.
• Participate in therapeutic activities – Do things that help recharge and rejuvenate your body. You might want to consider attending yoga, swimming therapy, or any activities that will make you feel calm and relax. In fact, even laughing and singing can help improve your condition little by little. ⁽⁸⁾
• Do not over strain your body – While you are encouraged to move around, still you have to keep in mind that there is a thin line between exercise and abuse. You might get frustrated because you can’t seem to do the things you usually do. In an attempt to regain your strength, you could probably push yourself too much. You need to understand that if you have antisynthetase syndrome, you are not like everyone else. You need to set a pace in everything you do. Working too hard can further damage your muscles. You can do what you want to, but make sure you are not causing damage to your body. ^{(8, 9, 10)}

References:

1. https://rarediseases.info.nih.gov
2. www.dermnetnz.org
3. https://en.wikipedia.org
4. www.orpha.net
5. www.mdedge.com
6. www.sciencedirect.com
7. www.raregenomics.org
8. www.malacards.org
9. https://understandingmyositis.org
10. www.the-rheumatologist.org