Speculation about cause of GCA
Numerous theories have been proposed in literature – some remain viable but unproven. Observations from various medical journal publications are listed chronologically by medical journal publication date. A bibliography of these articles is provided in Appendix 1:
- Since all of five patients studied had serologic findings indicating Chlamydia pneumoniae infection and all required corticosteroid treatment for symptomatic recovery we suggest that reinfection with Chlamydia pneumoniae may induce isolated and systemic vasculitis in virtually any organ of the body [1];
- Pronounced quarterly and annual variations of the incidence rate of histologically proven temporal arteritis in two counties were found, with a clustering in five peaks. These cyclic fluctuations were seen simultaneously in several regions. Two periods with an increased incidence of temporal arteritis and polymyalgia rheumatica occurred in close relation to epidemics of Mycoplasma pneumoniae infection. Two peak incidence rates were partly related to epidemics of Parvovirus B19 and one peak to an epidemic of Chlamydia pneumoniae. The synchronous variations in the incidences of temporal arteritis and polymyalgia rheumatica recorded in several regions of Denmark strongly indicate that an environmental infectious factor influences the frequencies. The close concurrence with the above-mentioned epidemics suggests that temporal arteritis and polymyalgia rheumatica may be triggered by certain viral and/or bacterial agents [2];
- Parvovirus B19 may play a role in the pathogenesis of giant cell arteritis [3];
- C. pneumoniae was found in temporal artery specimens of 8 of 9 GCA patients studied, in 1 specimen from a PMR patient, and in no other control specimens [4];
- Familial giant cell arteritis – a possible role of genetic traits [5];
- A complex interaction of multiple factors, such as age, sex, ethnic background, immunogenetic mechanisms and environmental influences, is probably involved [6];
- The immunologic features suggest the possible presence of a microorganism [7];
- Mercury-containing amalgam (dental fillings) may be an important risk factor for patients with autoimmune diseases [8];
- High prevalence of herpes simplex virus DNA were found in temporal arteritis biopsy specimens [9];
- Chlamydia pneumoniae has recently been implicated in the pathogenesis of several neurological diseases. As an intracellular parasite with its unusual life cycle it is able to circumvent the immune system and to persist in the organism. It has the ability to modify the function of the infected cell and supposedly induce autoimmune reactions. These properties can make it pathogenic in several chronic neurological diseases including multiple sclerosis, atherosclerosis, stroke, Alzheimer dementia and giant cell arteritis [10];
- Exposure to Chlamydia pneumoniae is extremely common, and its incidence increases with age. C pneumoniae infection is strongly associated with coronary artery disease, as well as with atherosclerosis of the carotid artery, aorta, and peripheral arteries [11];
- Solid malignancies (cancers) and hematological disorders, especially myelodysplastic syndromes (inability of bones to produce good cells), may represent precipitating factors for development of TA [12];
- Age related changes in the neuroendocrine system could represent a pathogenic factor in genetically disposed individuals [13];
- The respiratory pathogen Chlamydia (Chlamydophila) pneumoniae is associated with chronic diseases including atherosclerosis and giant cell arteritis, which are accompanied with occurrence of these obligate intracellular bacteria in blood vessels. There, C. pneumoniae seems to be present in a persistent state [14];
Pearl had eruptions of herpes simplex most of her adult life but this wasn’t pursued for special analysis or treatment during her illness. She had several amalgam dental fillings – these weren’t removed for GCA reasons but some were replaced with non-metallic fillings during maintenance procedures. The effects of herpes and amalgam on Pearl’s health, if any, were not identified. Mold exposure is another candidate that some patients believe may contribute to autoimmune problems though it is not widely publicized in medical journal articles. Pearl was exposed to household mold over a several year period due to an unobserved drain pipe leak. I believe each of these conditions could have contributed to an immune system overload.
Chlamydia is commonly thought of as a bacterial disease infecting the sexual organs – that form of Chlamydia is Chlamydia trachomatis. It is unlike Chlamydia pneumoniae that plays a role in vasculitis. Because Pearl had persistent involvement of her leg arteries I suspected that C. pneumoniae might be a likely candidate for medication therapy and proposed consideration of treatment to the Vascular Surgeon, Cardiologist, Clinic Rheumatologist, local Rheumatologist and Internist. Long-term treatment with antibiotics doxycycline or tetracycline would be needed. None of her specialists supported testing or pursuing treatment for C.pneumoniae for Pearl.
