In these cases there may be minor abnormalities on a kidney biopsy. Angiogram tests to look at the blood vessels in the kidney may show abnormal blood flow, perhaps causing a cramp like pain. The cause is not fully understood. It certainly is [more common] in women than in men, and there may be hormonal influences. Some women find the pain is worse at different times of their menstrual cycle, or comes on during pregnancy, or if they are taking [oral contraceptives].It has also been reported to be caused by microscopic granules of calcium oxylate into the glomerulus itself, causing blood vessels to rupture and increase the distention of the renal capsule.This condition may persist for some years, and can be lifelong. Damage to the kidneys leading to kidney failure does not occur. However, because LPHS is unusual in patients older than 60 years, some clinicians believe that LPHS eventually resolves.At this time no cure has been found for this disease. LPHS is a debilitating disease due to chronic pain and the inability to know how to control the glomerular aspect. The pain of LPHS can be worsened by acts as simple as riding in the car and undertaking daily activities. Many people with this disease are unable to maintain employment due to the debilitating pain. Unpublished research by Dr. Ahmed Ghanem (who has cared for well over 100 women with LPHS found that untreated  Symptomatic Nephroptosis - SN (Hypermobile kidney) can lead to LPHS. Nephropexy can help to relieve symptoms.
Angiotensin converting enzyme inhibitors are thought to be beneficial, as they reduce intraglomerular pressure and, presumably, reduce renal tubular congestion with RBCs.Possible treatment regimens

General
Angiotensin inhibition
Reduce the risk of nephrolithiasis

Pain control
Opioid therapy
Inpatient therapy
Intravenous opioid regimen
Antiemetic drugs
Pruritus management
Maintenance therapy between pain exacerbations

Invasive therapy
Implantable drug delivery system
Surgical renal denervation
Renal autotransplantation
Nephrectomy (NOT recommended)
Other invasive therapies (but not proven effective)
Pulse radio frequency
Celiac plexus block
Intraureteric capsaicin infusionSurgery (autotransplantation) is thought by some to be of benefit in selected individuals and advocated in some centres, but usually considered the last resort.Physicians discourage surgery, as LPHS symptoms often re-occur after autotransplantation. Epidemiology
LPHS is listed as a rare disease in the US National Institute of Health Rare Diseases database. While exact numbers worldwide are not available, the primary LPHS research clinic located in Ohio has over 200 patients. In addition, several hundred other patients have been reported in one study as of 2006. The prevalence of LPHS is estimated  at about 0.012 percent, which qualifies LPHS as a rare disease (prevalence less than 0.07 percent) according to the Rare Diseases Act of 2002. Those affected are usually young, with an average age of 31 years, and 70% to 80% are women. See also
Pelvic pain

References
External links

Loin Pain - Patient UK