Afferent arteriolar C3 disease--a distinct pathological entity

Treatment and Management of Loin Pain Hematuria Syndrome

PURPOSE OF REVIEW

Loin pain hematuria syndrome (LPHS) is rare and seldom diagnosed, yet it has a particularly significant impact on those affected. This is a review of the latest and seminal evidence of the pathophysiology and diagnosis of LPHS and presents the typical clinical presentation and treatment options available.

RECENT FINDINGS

LPHS is typically found in young women with characteristic symptoms, including severe recurrent flank pain and gross or microscopic hematuria. The majority of patients will experience crippling pain for many years without effective therapy, often requiring frequent use of narcotic medication. However, the lack of conclusive pathophysiology, in conjunction with the rarity of LPHS, has prohibited the development and trial of definitive treatment options. Nevertheless, in order to combat this rare but severe disease, management strategies have continued to evolve, ranging from conservative measures to invasive procedures. This review presents an overview of the current hypotheses on the pathophysiology of LPHS in addition to summarizing the management strategies that have been utilized. Only 30% of LPHS patients will experience spontaneous resolution, whereas the majority will continue to face chronic, crippling pain. Several methods of treatment, including invasive and non-invasive, may provide an improved outcome to these patients. Treatment should be individually tailored and multi-disciplinary in nature. Further research is required to further elucidate the pathophysiology and develop new, specific, treatment options.

Clinical and safety outcomes of laparoscopic nephrectomy with renal autotransplantation for the loin pain-hematuria syndrome: a 14-year longitudinal cohort study

OBJECTIVE

The objective of this study is to assess clinical and safety outcomes after laparoscopic nephrectomy with autotransplantation for loin pain-hematuria syndrome (LPHS).

METHODS

We conducted telephone interviews using structured questionnaires and retrospectively reviewed data on all patients who underwent laparoscopic nephrectomy with autotransplantation for LPHS between January 2000 and May 2014.

RESULTS

A total of 24 laparoscopic nephrectomies with renal autotransplantation of 21 patients with LPHS were reviewed. Eighty-three per cent were female with a mean age of 31 years. Postoperatively, graft loss resulting in subsequent nephrectomy occurred in two patients; However, no patients died (median follow-up = 22 months, range 5 to 78 months) or required dialysis (median follow-up = 10 months, range 0.2 to 178 months). There was no significant difference in estimated glomerular filtration rate (eGFR) before and after surgery (100 ± 22 vs. 97 ± 23 mL/min/1.73 m² ; P = 0.37). Among 14 patients (16 autotransplantation) with telephone follow-up, 14 (88%) resulted in pain relief and no operation resulted in worsening pain. All procedures resulted in immediate pain relief; pain recurrence was reported after two procedures. However, those patients had pain-free period up to 36 months. The quality of life was better after 15 (94%) autotransplantation with higher employment rate (44% vs. 69%; P = 0.04). Two patients with graft loss reported better pain control and quality of life.

CONCLUSIONS

Renal autotransplantation is a possible treatment option for LPHS refractory to conservative medical treatment. It can offer pain relief and better quality of life. Despite postoperative risk, it seems to be safe for survival and renal outcomes.

Loin pain hematuria syndrome

Loin pain hematuria syndrome (LPHS), first described in 1967, is a rare pain syndrome, which is not well understood. The syndrome is characterized by severe intermittent or persistent flank pain, either unilateral or bilateral, associated with gross or microscopic hematuria. LPHS is a diagnosis of exclusion as there still is not a consensus of validated diagnostic criteria, though several criteria have been proposed. The wide differential diagnosis would suggest a meticulous yet specific diagnostic work-up depending on the individual clinical features and natural history. Several mechanisms regarding the pathophysiology of LPHS have been proposed but without pinpointing the actual causative etiology, the treatment remains symptomatic. Treatment modalities for LPHS are diverse including simple analgesia, opioid analgesic and kidney autotransplantation. This review article summarizes the current understanding regarding the pathophysiology of LPHS along with the steps required for proper diagnosis and a discussion of the different therapeutic approaches for LPHS.

Extraglomerular C3 deposition and metabolic impacts in patients with IgA nephropathy

BACKGROUND

The aim of the present study was to explore the significance of extraglomerular (Bowman's capsule and/or arteriole) C3 (ex-C3) deposits in IgA nephropathy (IgAN).

METHODS

One hundred and seventy patients with IgAN were divided into two groups: Group A (n=79), patients who did not have ex-C3 deposits, and Group B (n=91), patients who had ex-C3 deposits.

RESULTS

At the time of renal biopsy, Group B was characterized by a marked increase in diastolic blood pressure, total cholesterol, triglyceride and low-density lipoprotein-cholesterol compared with those of Group A. After 4 years, the estimated glomerular filtration rate (eGFR) in Group B was significantly worse than that of Group A. Upon examination by electron microscopy, the arteriolar dense deposits in Group B were found to occur in significantly higher amounts than in Group A. One hundred and thirty-four patients underwent a 3-year follow-up study after intervention and were re-divided by therapeutic factors as follows: 'conventional therapy', treatment with anti-hypertensive drugs and/or anti-platelet drugs, and 'aggressive therapy', additional treatment with either tonsillectomy or corticosteroid. Patients treated with conventional therapy in Group B had significantly higher body mass index and levels of C3 and CH50 compared with other Groups. Aggressive therapy was significantly effective in urinary protein reduction in both Group A and Group B. Except for the patients who received aggressive therapy in Group A, the levels of the eGFR gradually declined.

CONCLUSIONS

It appears that IgAN patients who have ex-C3 deposits have worse clinical outcomes.

Proposed pathogenesis of idiopathic loin pain-hematuria syndrome

BACKGROUND

To study loin pain-hematuria syndrome (LPHS) pathogenesis, we evaluated 43 consecutive patients for whom urological evaluation failed to disclose the cause of their recurrent flank pain and hematuria. Each underwent percutaneous kidney biopsy. In 9 patients, the biopsy specimen showed immunoglobulin A nephritis, an established cause of LPHS. We suggest these cases be designated secondary LPHS. They are not included in this analysis. The remaining patients (N = 34) are designated idiopathic (primary) LPHS. They are the basis of this report.

METHODS

Demographics of patients with primary LPHS are mean age of 30.8 +/- 10.3 years; 74% women; 94% white; and history of kidney stones, 47%, although none was obstructing.

RESULTS

Primary LPHS kidney biopsy specimens showed red blood cells (RBCs) in multiple tubules, consistent with glomerular hematuria. Glomeruli were normal by means of light and immunofluorescent microscopy; however, more than 50% of biopsy specimens showed unusually thin or thick glomerular basement membranes. To assess whether the biopsy itself caused RBCs in tubules, we compared RBCs in renal tubular cross-sections from primary LPHS biopsies with those of normal kidneys (donors, n = 10). The mean percentage of tubular cross-sections containing RBCs was greater in primary LPHS than normal specimens (7.2% +/- 6.5% versus 1.6% +/- 1.0% [SD]; P < 0.0001), confirming glomerular hematuria in patients with primary LPHS.

CONCLUSION

Primary LPHS pathogenesis includes glomerular hematuria, apparently from structurally abnormal glomerular basement membrane. Primary LPHS pain may be initiated by obstructing RBC casts and perhaps microcrystals in those with a history of urolithiasis. Nevertheless, other factors are needed to explain the severe pain in patients with primary LPHS.

Loin pain-hematuria syndrome associated with thin glomerular basement membrane disease and hemorrhage into renal tubules

Loin pain-hematuria (LPH) syndrome is a poorly understood disorder in which the patients, mainly young women, experience unexplained severe chronic unilateral or bilateral flank pain associated with gross and/or microscopic hematuria. By contrast, thin glomerular basement membrane (GBM) disease is generally thought to be a benign disorder, affecting males and females equally, in which the major manifestation is asymptomatic microscopic hematuria. Herein we describe seven patients (6 females, 1 male) in whom thin GBM appeared to be the cause of the LPH syndrome. The gross hematuria in these patients could be attributed to thin GBM disease because the renal biopsy demonstrated red cells in renal tubules (indicating glomerular hematuria) and the only glomerular abnormality present with thin GBM. In addition, the other causes of gross hematuria were excluded by appropriate testing. The flank pain in these patients might also have been the result of their thin GBM disease. This is suggested by renal biopsy findings of multiple renal tubules filled with red cells, apparently occluding the tubules. We suggest that occlusion of a relatively small fraction of renal tubules could cause renal pain if back-leak of glomerular filtrate occurred that was of sufficient magnitude to expand renal parenchymal volume and stretch the renal capsule. Preliminary observations suggest that treatment with the angiotensin converting enzyme (ACE) inhibitor enalapril importantly reduces the frequency and severity of the episodes of gross hematuria and flank pain in most patients. ACE inhibition might decrease glomerular hemorrhage in patients with think GBM by decreasing glomerular hydrostatic pressure. We conclude that (1) Thin GBM disease can be the cause of gross hematuria, apparently as a result of rupture of thin GBM. (2) Rupture of thin GBM resulting in hemorrhage into renal tubules may be the cause of the flank pain and gross hematuria in some patients with the LPH syndrome.

Renal extraglomerular vascular immune deposits in IgA glomerulonephritis

Kidney biopsies of 425 patients with IgA glomerulonephritis were studied to reveal the incidence, composition and possible clinical significance of extraglomerular vascular immune deposits. IgA deposits were detected in 20 cases, IgM in 28 (in 5 together with IgA), C3 in 317 and no vascular deposits in 60 cases. C3 and IgA deposits were granular, resembling mesangial deposits, while IgM deposits were lumpy, similar to IgM deposits in sclerotic and hyalinized glomeruli. The incidence of vascular lesions in patients with IgA (30%) and C3 deposits (24%) was not significantly higher as compared to those without vascular deposits (20%), but was significantly higher in patients with IgM deposits (68%, P < 0.00004). Only the presence of vascular IgM deposits correlated significantly with severe glomerulosclerosis, arterial hypertension and elevated serum creatinine levels (all P < 0.001). We conclude that neither C3 nor IgA deposits, in spite of their suggested immune complex nature, contribute significantly to the development of vascular lesions. Lumpy IgM deposits, probably the result of insudation of plasma proteins into the blood vessel walls, were associated with advanced vascular lesions and glomerulosclerosis and are probably a part of non-immune mediated progression of IgA glomerulonephritis.

Renal autotransplantation in the loin pain-hematuria syndrome: a cautionary note

The current literature suggests that renal autotransplantation is nearly uniformly effective in controlling the severe and debilitating pain of the loin pain-hematuria syndrome (LPHS). However, we report two patients thought to have this syndrome in whom renal autotransplantation did not result in long-term control of pain. In case 1, autotransplantation resulted in immediate cessation of pain; however, the flank pain recurred 7 1/2 months later. The recurrent pain was also severe and debilitating, requiring narcotic medications for control. In case 2, autotransplantation of the left kidney resulted in chronic pain in the left pelvic area, the site of the autotransplanted kidney. In addition, the patient continued to experience chronic discomfort in the left flank and along the flank incision. One year after autotransplantation, the patient still requires multiple daily doses of narcotic medications for pain control. Our two patients represent the 13th and 14th reported patients subjected to renal autotransplantation for management of LPHS. They represent only the third and fourth reported patients with recurrence of pain after renal autotransplantation. Because studies with negative results are less likely to be reported in the literature than studies with positive results, it is possible that the literature overestimates the effectiveness of renal autotransplantation in the LPHS. To assess the true effectiveness of renal autotransplantation in LPHS, a survey of patients with LPHS who have undergone renal autotransplantation needs to be performed.