The majority of women on cyclic COCPs have regularly scheduled withdrawal bleeding, which is vaginal bleeding mimicking users menstrual cycles with the exception of lighter menstrual bleeding compared to bleeding patterns prior to COCP commencement. As such, a recent study reported that out of 1003 women taking COCPs approximately 90% reported regularly scheduled withdrawal bleeds over a 90-day standard reference period. Withdrawal bleeding usually occurs during the placebo, hormone-free days. Therefore, avoiding placebo days can diminish withdrawal bleeding among other placebo effects. Effectiveness
If used exactly as instructed, the estimated risk of getting pregnant is 0.3% which means that about 3 in 1000 women on COCPs will become pregnant within one year. However, typical use of COCPs by users often consists of timing errors, forgotten pills, or unwanted side effects. With typical use, the estimated risk of getting pregnant is about 9% which means that about 9 in 100 women on COCPs will become pregnant in one year.
Radiology
Chest radiographs of patients with PAM usually reveal bilateral diffuse micronodular calcifications, producing a "sandstorm” appearance that first involves the inferior portions and then the middle and upper portions of the lungs. High-resolution computed tomography
The most common findings on HRCT are diffuse hyperdense ground-glass attenuation and subpleural linear calcifications, often most predominant in the inferior and posterior portions of the lungs. Additionally, the medial aspects of the lungs appear to be more heavily involved than the lateral aspects. Ground-glass opacities, probably due to small calculi in the air space, are the most common finding in children and in patients with early-stage PAM. Magnetic resonance imaging
On magnetic resonance imaging (MRI), the calcific lesions usually show hypointensity or a signal void on T1- and T2-weighted images. Pulmonary function studies
Pulmonary function tests, arterial blood gases, ventilation perfusion relationships, and O2 diffusing capacity are normal in the initial stages of PAM. As the disease progresses, pulmonary function tests reveal typical features of a restrictive defect with reduced forced vital capacity (FVC) and elevated forced expiratory volume in FEV1/FVC. Treatment
To date, no treatment has been proven to effectively reverse or prevent the progression of PAM. Lung transplantation is an option for end stage disease, but is typically only recommended as a last resort when quality of life is significantly impaired.Etidronate is a bisphosphonate and can reduce the formation of calcium hydroxyapatite crystals. It has led to clinical and radiological improvements in few cases. Epidemiology
Since the disease was first described in 1918, over 500 case reports have appeared in the literature.