Loin Pain Hematuria Syndrome



Loin Pain Hematuria Syndrome


Xin Gu, MD





Key Facts


Etiology/Pathogenesis



  • Unknown or tubular obstruction from intranephron hemorrhage


Clinical Issues



  • LPHS is a diagnosis of exclusion


Microscopic Pathology



  • Normal or nonspecific



    • Arteriolar sclerosis and isolated glomerulosclerosis


    • Focal interstitial fibrosis or edema


    • RBCs and RBC casts in tubules


  • Immunofluorescence



    • Mesangial IgM/C3 reaction, arteriolar C3


  • Electron microscopy



    • Segmental thinning of GBM


Top Differential Diagnoses



  • Urologic causes



    • Neoplasms


    • Occult renal lithiasis


    • Kidney or bladder infection


    • Cystic renal disease


  • Glomerular diseases



    • IgA nephropathy


    • Thin basement membrane nephropathy


    • Glomerular diseases with nephritic presentation


  • Renal vascular diseases



    • Isolated polyarteritis nodosa


    • Vascular malformations


Diagnostic Checklist



  • Biopsy important to exclude specific causes







In general, kidney biopsies from LPHS patients do not reveal specific pathology. This image shows a normal glomerulus with patent capillary loops and delicate walls. The mesangium is inconspicuous.






This biopsy from an LPHS patient shows a histologically normal cortical tubulointerstitium. The proximal tubules show preserved brush borders. The tubules are back-to-back, and the interstitium is inconspicuous.


TERMINOLOGY


Abbreviations



  • Loin pain hematuria syndrome (LPHS)


Definitions



  • Recurrent pain in lower flanks and intermittent hematuria without identifiable cause


ETIOLOGY/PATHOGENESIS


Unclear



  • Proposed classification: Idiopathic disease vs. clinical mimics


  • LPHS: Idiopathic disease



    • Possible etiology: Glomerular capillary hemorrhage



      • RBC and RBC casts obstruct tubules, leading to backleak of glomerular filtration


      • Tubular injury and interstitial edema lead to capsular distension and pain


  • Clinical mimics of LPHS



    • IgA nephropathy


    • Thin basement membrane nephropathy


    • Occult nephrolithiasis


    • Vascular malformation


    • Inflammatory renal vascular diseases


    • Vascular spasm


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Diagnosis of exclusion, so incidence cannot be estimated from population-based studies


  • Age



    • Children and adults from 1st to 6th decade


    • Median age: Mid 30s


  • Gender



    • More common in females (70%) than in males (30%)


Presentation



  • Severe recurrent lower flank pain and hematuria



    • Pain is unilateral at initial presentation



      • Radiates to abdomen, inguinal and inner thigh


    • Eventually may develop bilateral flank pain


    • Hematuria may be gross or microscopic



      • Pain may not always be associated with hematuria


  • Physical examination is unremarkable and nonspecific



    • Costovertebral angle tenderness


    • Low-grade fever may be present


    • No hypertension, except preexisting


Laboratory Tests



  • Urine analysis may show RBCs and RBC casts


Treatment



  • Options, risks, complications



    • Multidisciplinary pain management



      • Analgesia: NSAIDs and opioids


      • Intraureteric capsaicin


      • Nerve blockade


      • Antidepressants


      • Nephrectomy with autotransplantation


Prognosis



  • Long-term prognosis is excellent



    • Renal function is well preserved


    • Spontaneous resolution in 30% after conservative treatment


IMAGE FINDINGS


Radiographic Findings



  • Normal or nonspecific


  • Minor vascular alterations may present


Tags:
Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Loin Pain Hematuria Syndrome

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