loin pain hematuria syndrome (LPHS)

Last edited 10/2021 and last reviewed 11/2021

Loin pain hematuria syndrome (LPHS)

  • was first described in 1967, is a rare pain syndrome (1,2,3,4) - but is not well understood

  • syndrome is characterized by severe intermittent or persistent flank pain, either unilateral or bilateral, associated with gross or microscopic hematuria
    • majority of patients affected are young females, in some series up to 70% - often white (1)
    • prevalence of about 0.012% (1)
    • majority of patients with LPHS show symptoms by the third decade of life (ranging from the first to sixth decades)
    • loin pain varies in duration and frequency; the duration can range from minutes to a constant ache and the frequency can vary from once or twice a year to incessant
      • the pain has also been described to radiate, in some cases, to the iliac fossa, anterior thigh or groin
      • loin pain is described as burning or throbbing, localized at the costovertebral angles, and made worse by a gentle punch or even slight bumps such as when riding in a car (4)
        • pain is mostly unilateral but can be bilateral either from the beginning or become bilateral over time
    • LPHS is not known to cause secondary kidney injury or increase mortality (1)
    • evidence from a series of 51 patients with LPHS (2)
      • LPHS resolved spontaneously in half the patients after several years (mean 3-5); the remainder of patients continued to have pain with the longest suffering for 17 years

  • LPHS is a diagnosis of exclusion as there is not a consensus of validated diagnostic criteria

  • several mechanisms regarding the pathophysiology of LPHS have been proposed but without pinpointing the actual causative etiology, the treatment remains symptomatic
    • many patients have a history of urinary obstruction
      • is theorized that this initial insult creates a cascade of chronic pain that can persist after the obstruction is resolved (3)
    • LPHS are postulated to be linked to vascular disease of the kidney, coagulopathy, renal vasospasm with microinfarction, hypersensitivity, complement activation on arterioles, venocalyceal fistula, abnormal ureteral peristalsis, and intratubular deposition of calcium or uric acid microcrystals (5)

  • treatment modalities for LPHS are diverse including simple analgesia, opioid analgesic and kidney autotransplantation
    • medical therapies, such as anticoagulation, beta-blockers, angiotensin inhibitors, and chronic pain control, have been proposed and are largely ineffective (3)