Abstract
Introduction
Spirulina platensis is a nutrient rich blue-green algae regarded as having health benefits including boosting the immune system, lowering cholesterol and providing anti-oxidant and anti-inflammatory properties. We present a case of dermatomyositis in a young lady who used spirulina following a sore throat who then developed myalgia and mild proximal myopathy with a significant rise in creatine kinase, with positive ANA, Ro and EJ antibodies. Occurrence of autoimmune rheumatic disease including dermatomyositis has been reported elsewhere in relation to the use of spirulina.
Case description
A 29 year old lady presented with myalgia, lethargy, fever and night sweats over 3 weeks. One month prior she had a sore throat and started taking spirulina believing this could support her immune system. There was no photosensitivity, sicca symptoms or Raynaud’s phenomenon reported. There was periorbital oedema, but no heliotrope rash or Gottron’s papules. Muscle power was MRC grade 4+/5 in arms and legs, proximally.
Creatine kinase was 13,523 U/L (normal 25-200); ALT 279 (normal <35). MRI showed quadriceps, hamstrings, abductors and gluteus maximus oedema bilaterally. Muscle biopsy was declined.
ANA was strongly positive (1:1280) with anti-Ro and anti-EJ antibodies also positive.
Troponin T was 728 ng/L (<14). ECG showed no ischaemic change, but small QRS complexes. Echocardiography and pulmonary function tests were normal. Cardiac MRI showed subtle pericardial gadolinium enhancement and normal myocardium.
CT thorax, abdomen and pelvis showed mediastinal and abdominal small volume lymphadenopathy. EBV IgG was positive but EBV IgM negative.
After IV methylprednisolone pulses, prednisolone 60 mg daily and IV immunoglobulins, the patient improved. However, due to patient concern about skin cancer risk, azathioprine was delayed leading to myositis relapse with a CK of 11,786 U/L. Troponin T was 3610 ng/L, and Troponin I was 46ng/L (0-16). Repeat echo was normal. Her TPMT levels were low but she agreed to start azathioprine, titrated to 75 mg daily.
Intravenous immunoglobulins were given again; afterwards developed right sided pleuritic chest pain. Chest X-ray showed right upper zone subpleural consolidation. CT pulmonary angiogram showed right lower lobe subsegmental artery filling defect suggesting pulmonary embolism. Prior to enoxaparin, lupus anticoagulant returned positive but anti-cardiolipin and B2GP1 antibodies negative. After starting warfarin, she developed widespread erythema, settling on withdrawal of warfarin and enoxaparin continued. Six months later she remained on azathioprine and CK now 58 U/L.
Discussion
Anti-EJ is a myositis specific antibody against the aminoacyl tRNA synthetases, and its target antigen is cytoplasmic. Clinically, anti-EJ antibodies are associated with anti-synthetase syndrome and interstitial lung disease, and is seen in around 1% of cases of idiopathic inflammatory myopathy (IIM). Anti-Ro52 is most often associated with Sjogren’s syndrome but is also a myositis associated antibody with an association with interstitial lung disease (ILD) and can also be found in patients with SLE, systemic sclerosis and mixed connective tissue disease. A review of 51 EJ positive interstitial lung disease patients has shown concurrent Ro52 positivity in 92.2%.
A review of cases of autoimmune disease associated with spirulina consumption has identified four articles with five cases: 3 patients with dermatomyositis and 2 with pemphigus. One of the three dermatomyositis cases was associated with positive Mi-2 antibodies. Animal studies have demonstrated spirulina induced enhancement of macrophage function in chicks. A human study has shown increased natural killer cell activity and release of interferon gamma following oral administration of an extract of spirulina. Spirulina stimulates Interferon beta, IFN gamma and TNFalpha production and this may play a role in triggering autoantibody production.
Epstein Barr virus has been implicated in the development of IIM in childhood. Our patient had positive EBV IgG suggestive of previous exposure.
Regular screening for ILD is important for patients with anti-synthetase syndrome related autoantibodies. Pregnancy planning will also be relevant in the coming years given her positive Ro52 antibody and lupus anticoagulant.
Confirmation of a persistent lupus anticoagulant is required since her thrombosis could have been provoked by IV immunoglobulin therapy. Repeat full antiphospholipid screen off anticoagulation is planned after 6 months of enoxaparin.
Vigilance for malignancy, including lymphoma is also relevant. Escalation to rituximab may be considered if there is disease progression or organ-threatening disease.
Key learning points
There is increasing awareness of a possible association between spirulina platensis consumption and development of idiopathic inflammatory myopathy.
History taking in patients presenting with symptoms suggestive of idiopathic inflammatory myopathy and other autoimmune disorders should include enquiry about consumption of spirulina and other supplements.
Patients with existing idiopathic inflammatory myopathy should be cautioned regarding taking dietary supplements containing spirulina since this may lead to flare or progression of their disease.
Further reporting of cases is required to better understand this association, and also study the effects of spirulina on the human immune system.
Testing for myositis specific antibodies is helpful in determining prognosis, can prompt further investigation for malignancy and informs planning of treatment.
Anti-EJ antibody is rare among cases of IIM and anti-synthetase syndrome but is associated with interstitial lung disease.
Screening for antiphospholipid syndrome at diagnosis of an autoimmune connective tissue disease is helpful.
Shared decision making and careful communication with patients around risks and benefits of rheumatological treatments remains important, as well as informed discussions around use of over the counter supplements.