Diagnosing a rare disease early is important, as it allows for prompt intervention and treatment. Recently, researchers took large steps forward in the diagnostics of pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE). While this comorbidity is rare within the SLE patient population, when it does appear, it is severe and possibly even fatal.
SLE, which is more commonly known as lupus, is an autoimmune disease in which the immune system attacks the body’s own tissue. Lupus causes inflammation, pain, and in severe cases, tissue damage to the joints, kidney, skin, heart, lungs, and brain. People who have SLE can experience flare-ups, in which the symptoms are at their worst, and periods of remission, where they have little to no pain. Every case is different, and people experience various levels of severity. This disease also disproportionately affects females and people of African American, Asian, and American Indian descent. It is also an invisible illness, meaning that there are no external factors that are noticeable to others. Because of this, many people go without a diagnosis. In fact, an average of six years passes between the onset of symptoms and the medical diagnosis for lupus, according to The Lupus Foundation of America. While there is no cure for SLE, treatment does exist. It is a lifelong process, and it can help to reduce flare-ups and pain.
PAH is a progressive form of high blood pressure that is characterized by the thickening of the pulmonary arteries. These arteries become blocked, which forces the heart to work harder to push blood through, which then leaves less oxygen-rich blood for the rest of the body. Additionally, the heart gets weaker as it has to work harder and harder to do its job. These issues lead to symptoms such as chest pain, fatigue, fainting, dizziness, shortness of breath, and swelling in the legs and ankles.
A mutated BMPR2 gene can cause this condition, although the use of street drugs or other diseases – such as SLE – can also result in PAH. If the cause is genetic, the mutation is passed down in an autosomal dominant pattern. In terms of treatment, there is no cure; it focuses on slowing progression and addressing symptoms. Options include vasodilators, guanylate cyclase stimulators, sildenafil, endothelin receptor agonists, tadalafil, warfarin, high-dose calcium channel blockers, diuretics, oxygen therapy, digoxin, atrial septostomy, and a lung or heart transplant.
Diagnosing PAH in SLE Patients
408 patients participated in this study, all of whom had SLE. Researchers wanted to find information that could be useful for diagnosing PAH in lupus patients, as it is a severe complication that results in two-year mortality in up to 50% of cases. Additionally, a better diagnostic process would lead to earlier diagnoses, which improves outcomes and prevents further organ damage.
While methods currently exist to diagnose PAH, such as right heart catheterization and echocardiology, they are either costly, invasive, or just not feasible. Instead, the researchers wanted to identify a method to see which patients are at a heightened risk of PAH.
In order to do so, they performed a chart review of all 408 patients, finding that 34 (8.3%) of them also had PAH. Within this group, there was a higher likelihood of myocardial damage, interstitial pneumonitis, and polyserositis. These patients also had lower rates of anti-ribosomal RNA protein antibodies and anti-double-stranded DNA.
On the other hand, the researchers also identified criteria that did not help to differentiate between PAH-negative and -positive patients. For one, neither group had differences in SLE disease activity or ejection fraction. Lupus nephritis was not found to be a risk factor for PAH either.
In the end, these data will help medical professionals to better recognize, screen, and diagnose PAH within lupus patients earlier.
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