Drug-induced acute interstitial nephritis with granulomas

A framework for exclusion of alternative diagnoses in sarcoidosis

Sarcoidosis is a multisystem granulomatous syndrome that arises from a persistent immune response to a triggering antigen(s). There is no "gold standard" test or algorithm for the diagnosis of sarcoidosis, making the diagnosis one of exclusion. The presentation of the disease varies substantially between individuals, in both the number of organs involved, and the manifestations seen in individual organs. These qualities dictate that health care providers diagnosing sarcoidosis must consider a wide range of possible alternative diagnoses, from across a range of presentations and medical specialties (infectious, inflammatory, cardiac, neurologic). Current guideline-based diagnosis of sarcoidosis recommends fulfillment of three criteria: 1) compatible clinical presentation and/or imaging 2) demonstration of granulomatous inflammation by biopsy (when possible) and, 3) exclusion of alternative causes, but do not provide guidance on standardized strategies for exclusion of alternative diagnoses. In this review, we provide a summary of the most common differential diagnoses for sarcoidosis involvement of lung, eye, skin, central nervous system, heart, liver, and kidney. We then propose a framework for testing to exclude alternative diagnoses based on pretest probability of sarcoidosis, defined as high (typical findings with sarcoidosis involvement confirmed in another organ), moderate (typical findings in a single organ), or low (atypical/findings suggesting of an alternative diagnosis). This work highlights the need for informed and careful exclusion of alternative diagnoses in sarcoidosis.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Study of Acute Kidney Injury on 309 Hypertensive Inpatients with ACEI/ARB - Diuretic Treatment

BACKGROUND

The present study investigated risk factors for acute kidney injury (AKI) in patients found to be hypertensive during hospitalization who were prescribed angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor antagonists (ARB) + diuretic combinations, in order to determine which type of diuretic or combination of diuretics used in ACE/ARB-treated patients leads to a higher risk of acute kidney injury.

METHOD

Data on basic information, medical history, diagnostic information and medications prescribed were obtained from the patients' medical records. Retrospective analysis of potential risk factors and ACEI/ARB + diuretic use with AKI was performed.

RESULTS

Multivariate analysis showed initial risk factors for AKI to be chronic kidney disease and poor cardiac function. In univariate analysis, patients whose baseline serum creatinine was between 115 and 265 μmol/L also had a higher risk of AKI. The combination of furosemide and spironolactone produced only approximately a third of the risk of AKI as the combination of hydrochlorothiazide and spironolactone.

CONCLUSIONS

Chronic kidney disease and poor cardiac function are major risk factors for AKI in hypertensive inpatients using ACEI/ARB + diuretic therapy. The combination of thiazide diuretic and aldosterone antagonist had a higher risk of AKI than other single diuretics or diuretic combinations.

Medication-Induced Interstitial Nephritis in the 21st Century

Interstitial nephritis is an immune mediated form of tubulointerstitial kidney injury that may occur secondary to drugs, autoimmune disease, infections, and hematologic disorders or as a reactive process. Drug-induced acute interstitial nephritis (DI-AIN) occurs in 0.5%-3% of all kidney biopsies and in 5%-27% of biopsies performed for acute kidney injury. Drugs are implicated in 70%-90% of biopsy-proved IN with a prevalence of 50% in less developed to 78% in more developed countries. DI-AIN typically is idiosyncratic because of a delayed hypersensitivity reaction, although some chemotherapeutic agents are permissive for immune upregulation and injure the kidney in a dose-related manner. Antibiotics are the most implicated class of medication in DI-AIN, followed by proton pump inhibitors, nonsteroidal anti-inflammatory agents, and 5-aminosalicylates. Diuretics, allopurinol, phenytoin and other anti-seizure medications, and H2 receptor antagonists are known offenders while chemotherapeutic agents are an under-recognized cause. The symptoms of DI-AIN are variable and often not specific; thus, kidney biopsy is required to make a firm diagnosis. The incidence of DI-AIN appears to be increasing, particularly in the elderly in whom kidney biopsy is underused, and identification of the offending agent may be complicated by polypharmacy. As rapid drug discontinuation may improve prognosis, the possibility of DI-AIN should always be considered in a patient with acute kidney injury.

Renal allograft granulomatous interstitial nephritis: observations of an uncommon injury pattern in 22 transplant recipients

Background: Granulomatous interstitial nephritis (GIN) is uncommon in native kidneys, and descriptions in allografts are few. We report clinical and pathologic findings in 22 allograft recipients with GIN identified in renal allograft biopsies and nephrectomies.

Methods: Renal allografts with GIN were retrieved from the pathology files of two academic medical centers. Available clinical and pathologic data were compiled retrospectively for a 23-year period.

Results: GIN was present in 23 specimens from 22 patients (15 males and 7 females) with allograft dysfunction [serum creatinine averaged 3.3 mg/dL (range 1.4–7.8)], at a mean age of 48 years (range 22–77). GIN was identified in 0.3% of biopsies at a mean of 552 days post transplantation (range 10–5898). GIN was due to viral (5), bacterial (5) and fungal (2) infections in 12 (54.5%), and drug exposure was the likely cause in 5 cases (22.7%). One had recurrent granulomatosis with polyangiitis. In 4 cases, no firm etiology of GIN was established. Of 18 patients with follow up data, 33.3% had a complete response to therapy, 44.5% had a partial response and 22.2% developed graft loss due to fungal and E. coli infections. All responders had graft survival for more than 1 year after diagnosis of GIN.

Conclusions: Allograft GIN is associated with a spectrum of etiologic agents and was identified in 0.3% of biopsies. Graft failure occurred in 22% of this series, due to fungal and bacterial GIN; however, most had complete or partial dysfunction reversal and long–term graft survival after appropriate therapy.

Granulomatous interstitial nephritis

Granulomatous interstitial nephritis (GIN) is a rare entity detected in ∼0.5-0.9% of all renal biopsies. GIN has been linked to several antibiotics such as cephalosporins, vancomycin, nitrofurantoin and ciprofloxacin. It is also associated with NSAIDs and granulomatous disorders such as sarcoidosis, tuberculosis, fungal infections, and granulomatosis with polyangiitis. Renal biopsy is critical in establishing this diagnosis, and the extent of tubular atrophy and interstitial fibrosis may aid in determining prognosis. Retrospective data and clinical experience suggest that removal of the offending agent in conjunction with corticosteroid therapy often results in improvement in renal function. We describe a patient with a history of multiple spinal surgeries complicated by wound infection who presented with confusion and rash with subsequent development of acute kidney injury. Urinalysis demonstrated pyuria and eosinophiluria, and renal biopsy revealed acute interstitial nephritis with granulomas. These findings were attributed to doxycycline treatment of his wound infection. This review explores the clinical associations, presentation, diagnosis, and treatment of this uncommon cause of acute kidney injury.

Autopsy Renal Pathology

We provide an overview of assessment of the kidneys at autopsy, with special considerations for pediatric versus adult kidneys. We describe the approach to gross examination, tissue allocation when needed for additional studies of potential medical renal disease, the spectrum of congenital abnormalities of the kidneys and urinary tract, and approach to cystic diseases of the kidney. We also discuss common lesions seen at autopsy, including acute tubular injury, ischemic versus toxic contributions to this injury, interstitial nephritis, and common vascular diseases. Infections commonly involve the kidney at autopsy, and the key features and differential diagnoses are also discussed.

Giant Cell Tubulitis with Tubular Basement Membrane Immune Deposits: A Report of Two Cases after Cardiac Valve Replacement Surgery

This paper presents two elderly patients who had normal baseline renal function and had stenotic valvular lesions secondary to rheumatic fever and underwent aortic valve replacements with mechanical valves. Both patients developed acute renal failure after cardiac valve replacement procedures. The renal biopsies revealed acute granulomatous tubulointerstitial nephritis. The unique histologic features were tubular basement membrane (TBM) immune complex deposition detected by both immunofluorescence and electron microscopy and prominent multinucleated giant cells surrounding intact TBM. The temporal relationship to the surgical procedure and the subsequent recovery of the patients' renal functions upon therapy suggested that the renal failure may have been due to an allergic drug reaction from the perioperative exposure to unknown agents, such as prophylactic antibiotics and furosemide. The literature on TBM immune complex deposition was reviewed, and the pathophysiologic mechanisms that may account for the similarities between the clinicopathologic features of these two cases were examined. These two cases expand the histopathologic spectrum of previously described cases of putative drug-induced acute tubulointerstitial nephritis.

Risk Factors for Acute Renal Insufficiency Induced by Diuretics in Patients With Congestive Heart Failure

BACKGROUND

In patients with congestive heart failure (CHF), continuous diuretic therapy may result in acute renal insufficiency (ARI). This study examines factors contributing to this complication.

METHODS

We analyzed clinical data from 318 consecutive patients who were hospitalized for CHF. All were treated with diuretics and had echocardiography performed within 4 days of hospitalization. Systolic left ventricular (LV) dysfunction is defined as an ejection fraction less than 50%, and diastolic LV dysfunction, as an ejection fraction of 50% or greater in the presence of LV hypertrophy and a reversed E/A ratio.

RESULTS

ARI, defined as a 25% increase in serum creatinine level, occurred in 110 patients (35%) after diuretic therapy. Risk factors for ARI on univariate analyses were older age, higher baseline serum creatinine level, lower baseline serum sodium level, lower mean arterial pressure (MAP) during diuretic therapy, and greater doses and longer duration of diuretic therapy. In multivariate analyses, ARI occurred more frequently in patients with systolic (40%) than diastolic dysfunction (28%). The use of digoxin in patients with systolic LV dysfunction was observed to decrease the risk for ARI by 61%, independent of other agents used for the treatment of patients with CHF.

CONCLUSION

Age, baseline renal function and serum sodium concentration, MAP, and intensity of diuretic therapy can identify individuals at risk for ARI while receiving diuretic therapy for CHF. This complication is observed more often in individuals with systolic dysfunction, and its risk may be decreased with the use of digoxin.

Acute granulomatous interstitial nephritis secondary to bisphosphonate alendronate sodium

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world and is characterized by a progressive accumulation of functionally incompetent monoclonal lymphocytes. Renal involvement has been described in CLL but is uncommon. Granulomatous interstitial nephritis is a rare but characteristic hallmark of certain diseases such as sarcoidosis and tuberculosis. These epithelial reactions have also been reported with medications, infections, inflammation, Wegener's granulomatosis, and jejunoileal bypass. We present a 74-year-old woman with a stage 0 chronic lymphocytic leukemia who developed acute renal failure following the initiation of alendronate. The renal biopsy revealed an acute granulomatous interstitial nephritis. Infectious and inflammatory etiologies were ruled out. Hemodialysis was required despite discontinuation of all medications. Partial recovery of renal function occurred after 6 weeks of prednisone therapy and cyclophosphamide. This report describes a unique case of acute granulomatous interstitial nephritis and leukemic cell kidney infiltration by CLL.

Drug-induced tubulo-interstitial nephritis secondary to proton pump inhibitors: experience from a single UK renal unit

BACKGROUND

Acute tubulo-interstitial nephritis (TIN) is an important cause of acute renal failure, and is often caused by hypersensitivity to drugs. The aim of this study was to determine the aetiology of interstitial nephritis among an unselected cohort of patients, and to identify those drugs commonly implicated.

METHODS

A single-centre retrospective analysis was carried out of renal biopsy results from 296 consecutive patients between 1995 and 1999.

RESULTS

Acute TIN was identified in 24 (8.1%) biopsies. Eight out of 14 cases with presumed drug-related TIN could be attributed to the proton pump inhibitors omeprazole and lansoprazole. The two cases of lansoprazole-associated TIN are the first to be reported with this drug. The presentation and favourable response to treatment of these patients are described.

CONCLUSION

Drugs are the most common cause of interstitial nephritis in the population studied. Those drugs most commonly associated with interstitial nephritis were the proton pump inhibitors omeprazole and lansoprazole.

Granulomatous tubulointerstitial nephritis induced by all-trans retinoic acid

We report the first case of granulomatous tubulointerstitial nephritis induced by all-trans retinoic acid (ATRA) in a patient with acute promyelocytic leukemia (APL). Acute renal failure during treatment with ATRA has been previously reported as a part of an ATRA syndrome or a thrombotic complication of a hypercoagulable state. This case indicates an alternative mechanism of acute renal failure occurring during ATRA therapy.

The clinical and pathologic implications of plasmacytic infiltrates in percutaneous renal allograft biopsies

Plasmacytic infiltrates in renal allograft biopsies are uncommon and morphologically distinctive lesions that may represent variants of acute rejection. This study sought significant clinical and pathologic determinants that might have influenced development of these lesions and assessed their prognostic significance. Renal allograft biopsies (n = 19), from 19 patients, with tubulointerstitial inflammatory infiltrates containing abundant plasma cells, composing 32 +/- 8% of the infiltrating mononuclear cells, were classified using Banff '97 criteria. Clonality of the infiltrates was determined by immunoperoxidase staining for kappa and lambda light chains and polymerase chain reaction for immunoglobulin heavy-chain gene rearrangements, using V(H) gene framework 3 and JH consensus primers. In situ hybridization for Epstein-Barr virus encoded RNA (EBER) was performed in 17 cases. The clinical features, histology, and outcome of these cases were compared with kidney allograft biopsies (n = 17) matched for time posttransplantation and type of rejection by Banff '97 criteria, with few plasma cells (7 +/- 5%). Sixteen of 19 biopsies (84%) with plasmacytic infiltrates had EBER-negative (in 14 cases tested) polyclonal plasma cell infiltrates that were classifiable as acute rejection (types 1A [4], 1B [10], and 2A [2]). These biopsies were obtained between 10 and 112 months posttransplantation. Graft loss from acute and/or chronic rejection was 50% at 1 year and 63% at 3 years, and the median time to graft failure was 4.5 months after biopsy. There was no significant difference in overall survival or time to graft failure compared with the controls. Three of 19 biopsies (16%) had EBER-negative polyclonal plasmacytic hyperplasia, mixed monoclonal and polyclonal polymorphous B cell hyperplasia, and monoclonal plasmacytoma-like posttransplantation lymphoproliferative disease (PTLD) and were obtained at 17 months, 12 weeks, and 7 years after transplantation, respectively. Graft nephrectomies were performed at 1, 19, and 5 months after biopsy, respectively. Plasmacytic infiltrates in renal allografts comprise a spectrum of lesions from acute rejection to PTLD, with a generally poor prognosis for long-term graft survival.

Acute granulomatous interstitial nephritis and colitis in anticonvulsant hypersensitivity syndrome associated with lamotrigine treatment

We present the case of a 17-year-old woman with a history of bipolar disorder, who developed a clinical syndrome manifested by fever, lymphadenopathy, skin rash, diarrhea, and acute renal failure requiring dialysis after the use of lamotrigine. Renal biopsy showed acute interstitial nephritis (AIN) with focal granulomas. Similarly, colonic biopsy specimens showed colitis and ileitis with non-necrotizing epithelioid granulomas. The patient had a complete recovery after withdrawal of the medication and steroid treatment. Although lamotrigine has been previously implicated in the development of anticonvulsant hypersensitivity syndrome, there have been no previous reports of acute granulomatous interstitial nephritis or colitis associated with the use of this drug.

End-stage renal disease in sarcoidosis of the kidney

We describe two cases of black women with biopsy-proven sarcoidosis of the kidney who developed end-stage renal disease. Treatment with high-dose glucocorticoids resulted in a good initial response, followed by progressive deterioration of renal function requiring hemodialysis.

Drug-induced acute interstitial nephritis in renal allografts: histopathologic features and clinical course in six patients

Drug-induced acute interstitial nephritis is a common cause of dysfunction in native kidneys, but is rarely reported in renal allografts. This report describes six renal transplant recipients with acute renal allograft dysfunction or delayed allograft function in whom a renal transplant biopsy showed histopathologic features of drug-induced interstitial nephritis with no diagnostic evidence of acute rejection, cyclosporine or tacrolimus nephrotoxicity, or other lesion that could account for the graft dysfunction. In five of the six patients, interstitial nephritis occurred within 4 weeks of transplantation. All the patients were receiving trimethaprim-sulfamethoxazole and/or other drugs associated with interstitial nephritis. After discontinuation of these drugs and short-term corticosteroid treatment, all patients showed improvement in renal function, although the time course of this improvement varied considerably, with three patients showing a return to baseline serum creatinine level within 2 weeks and two patients showing a gradual improvement over 8 weeks. Four of the five patients followed up for more than 1 year (range, 14 to 33 months) after the episode of interstitial nephritis had good allograft function (serum creatinine level </= 1.6 mg/dL) at most recent follow-up, with one patient who had graft loss because of severe rejection 7.5 months after the development of interstitial nephritis. These findings suggest drug-induced interstitial nephritis may be an infrequent cause of graft dysfunction in kidney transplant recipients. Drug-induced interstitial nephritis is a reversible lesion that should be considered in the differential diagnosis of acute renal allograft dysfunction.

Phenotypic Characterization of Kidney Infiltrating Cell Subsets in Idiopathic Acute Interstitial Nephritis Associated with Uveitis: Evidence for a Cell-Mediated Immune Disease

The association of acute interstitial nephritis (AIN) and anterior uveitis without determined cause is quite rare. This disease entity is manifested by uveitis which may precede, occur concomitantly with, or follow AIN. Renal involvement is characterized by acute renal failure which is usually associated with a diffuse interstitial infiltration mainly by mononuclear cells. We report here the clinicopathological features in two cases of this association showing a different time course evolution of the renal disease. Repeat kidney biopsy allowed to study in different points of the disease process both the histological picture and the phenotypic characterization (by an immunohistochemical method) of cells infiltrating the renal interstitium. Immunohistochemical analysis of renal tissue revealed that interstitial infiltrate was primarily composed of T lymphocytes (mainly helper-inducer T cells) and monocytes/macrophages. A clear predominance of memory T lymphocytes (CD45RO+) in the interstitial infiltration was found. These cells persisted in the renal interstitium of the patient in whom renal function remained persistently impaired. The cellular profile of immunocompetent cells in renal lesions suggests a major role for cell-mediated immunity in the development of idiopathic AIN associated with uveitis.

Granulomatous interstitial nephritis

Granulomatous interstitial nephritis is a rare condition whose pathogenesis is poorly understood. Of 203 renal biopsies performed between 1974 to 1994 in which interstitial nephritis was the predominant change, granulomata occurred in 12. The authors reviewed the records of these patients and performed immunopathologic and immunohistochemical studies in their biopsies to characterize the phenotype of infiltrating cells. The authors used markers for T cells, B cells, and macrophages, and determined whether they were activated through assessment of upregulation of HLA-DR molecules. Additionally, the authors attempted to delineate whether or not tubules contributed to giant cell formation through assessment of intermediate filament for keratins and macrophage markers in epithelioid cells. Drug (aspirin, gentamycin, or combination of drugs), infection (Echerichia coli or various organisms), and sarcoidosis accounted for granulomatous inflammation in three patients each, Wegener's granulomatosis and oxalosis resulting from intestinal bypass in one patient each, and in one patient the possible cause could not be determined. Except for biopsies of granulomatous inflammation resulting from infection, in which neutrophils predominated, in all other biopsies, T cells and macrophages made up most of the inflammatory cell infiltrate. HLA-DR was upregulated in mononuclear cells infiltrating the interstitium and was expressed in proximal tubular cells and endothelial cells in all but biopsies of patients with sarcoidosis. In no instance was there evidence that tubules contributed epithelial cells to giant cell formation. These findings are consistent with the notion that granulomatous interstitial nephritis is a cell-mediated form of tissue injury in which T cell-macrophage seem to play a major role.

Ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis

Ciprofloxacin is known to cause acute interstitial nephritis. We report the first case of ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis. The patient presented with acute renal failure and skin lesions following a 14-day course of ciprofloxacin administered for cellulitis. The patient had symmetric, palm-sized, tender violaceous plaques on both axillae. The renal biopsy revealed granulomatous interstitial disease. A skin biopsy revealed an elastolytic process with histocytic infiltration and calcification. After discontinuing ciprofloxacin and starting a short course of steroid therapy, the skin lesion and renal function improved promptly. The nephritis relapsed after prednisone was discontinued and responded to a second course of steroid therapy. Ciprofloxacin, like penicillin, can cause granulomatous interstitial nephritis and elastolysis. A prolonged course of steroid therapy may be indicated in patients with ciprofloxacin-induced granulomatous interstitial nephritis to avoid early relapse.

Toxicology and carcinogenicity studies of diuretics in F344 rats and B6C3F1 mice. 2. Furosemide

Toxicology and carcinogenesis studies of furosemide, a widely used diuretic, were conducted by administering diets containing the drug to both sexes of F344 rats and B6C3F1 mice in 14-day, 13-week and 2-year studies. Deaths occurred among rats and mice receiving diets containing 46,000 ppm furosemide in 14-day studies, and animals given diets containing lower concentrations lost weight. No deaths were seen in 13-week studies using top concentrations ranging from 10,000 to 20,000 ppm, but animals at higher concentrations had lower weight gains than controls. Nephrosis in rats and mice was the only significant compound-related lesion observed in the prechronic studies. In 2-year studies, rats received diets containing 0, 350 or 700 ppm furosemide and mice received diets containing 0, 700 or 1400 ppm furosemide. Survival of dosed and control rats of both sexes and male mice was similar; survival of high-dose female mice was lower than controls. Nephropathy was increased in male rats and in male and female mice. In female mice, increased malignant tumors of the mammary gland were associated with furosemide administration. In male rats, marginal increases in tubular cell neoplasms of the kidney and in meningiomas of the brain were observed in dosed animals, but these were not considered to be related clearly to exposure to furosemide.

Hypersensitivity angiitis with granulomatous glomerulitis in a patient with preexisting IgA nephropathy

Following a 6-year history of asymptomatic proteinuria and microhematuria, a 51-year-old man suffered from acute systemic eruption, liver dysfunction and acute renal failure immediately after developing a cold and taking drugs including piroxicam, aspirin and bristocycline. Renal biopsy revealed progressive IgA nephropathy associated with acute tubulointerstitial nephritis and granulomatous glomerulitis. Although the drug actually responsible for this condition was not defined, it is likely that drug-induced hypersensitivity angiitis with granulomatous glomerulitis was superimposed on preexisting IgA nephropathy in this patient.

Induction, characterization, and cell transfer of autoimmune tubulointerstitial nephritis

Autoimmune tubulointerstitial nephritis (TIN) was induced in Lewis (LEW) rats by immunization with homologous Brown-Norway (BN) rat renal basement membrane (RBM), complete Freund's adjuvant and Bordetella pertussis vaccine. The BN strain has a tubular basement membrane (TBM) antigen (Ag+) detectable by immunofluorescence which is lacking in unmodified LEW rat TBM. Development of TIN in LEW rats correlated with TBM Ag+ immunogens from homologous and heterologous RBM preparations. By day 14 after immunization TIN developed characterized by elevated serum creatinine levels and by tubular destruction with focal, circumscribed lesions containing epithelioid cells, giant cells and mononuclear cell infiltrates. Approximately 60% of the mononuclear cells bore T cell antigens with most cells expressing Ia markers. Immunofluorescence and elution studies revealed no selective IgG fixation to TBM at day 14 despite high titers of circulating alloantibody reactive with the immunizing TBM. Intravenous transfer of LNC and/or splenic cells (3.5 to 7 X 10(8)) to naive LEW rats resulted in less severe but histologically identical TIN in seven days with T cell subpopulations similar to those seen in the active model. This model strongly suggests an initiating role for cell-mediated immunity in TIN in the rat and may provide a parallel to human TIN.

Dyazide-induced reversible acute renal failure associated with intracellular crystal deposition

Acute interstitial nephritis due to Dyazide therapy, ie, a combination of hydrochlorothiazide (25 mg) and triamterene (50 mg), has been recently reported in the literature. This had been characterized by nonoliguric renal failure after a long latent period (weeks) following exposure to the drug. Pathologic data have indicated a drug-induced hypersensitivity reaction. We report here one case of oliguric acute renal failure after a massive Dyazide intoxication. Based on the results of the renal biopsy and clinical course, we propose that the oliguria was secondary to a direct toxic effect on the tubules, and intrarenal obstruction was secondary to triamterene crystals and crystal-laden cells. In addition, pathologic findings also suggested a moderate hypersensitivity reaction. After hemodialysis and short-term steroid therapy, the patient achieved complete recovery of renal function within 12 days. Recent knowledge of triamterene-induced nephrolithiasis helps to explain the pathogenesis of acute renal failure in this patient, and is briefly reviewed here.

Renal and urinary tract complications following the intravesical instillation of formalin

The case is reported of a 10-yr-old girl who developed intractable hematuria from hemorrhagic cystitis following chemotherapy for a malignant lymphoma. Following the intravesical instillation of formalin, which controlled the hematuria, she developed oliguria attributable to ureteric stenosis and fibrotic contraction of the renal pelves. Bilateral nephrostomies were constructed, but recurrent pyelonephritis and further renal pelvic obstruction developed. A series of renal biopsies and ultimately bilateral nephrectomy revealed severe, chronic interstitial nephritis, massive renal interstitial accumulation of deposits probably containing Tamm-Horsfall protein and, in the left nephrectomy specimen, a florid interstitial chronic granulomatous inflammatory reaction. Although ureterohydronephrosis has been described by others as a complication of the intravesical instillation of formalin, fibrotic contraction of the upper urinary tract and the florid interstitial nephritis with granulomata as described herein have not previously been reported. It is proposed that vesicoureteric reflux of formalin, perhaps accompanied by intrarenal reflux, caused or contributed to these pathological changes.

Renal granulomatous angiitis--a case report

A case of non-necrotizing granulomatous angiitis without significant glomerular pathology is described in a 61 yr-old female. The characteristic lesion consists of periarterial inflammation comprising a mixed population of mononuclear cells with prominent giant cell formation. There is no evidence of immunoglobulin, complement or fibrin deposition. It is concluded that this represents an unusual variant of polyarteritis nodosa which is apparently controlled by steroid therapy.

Effects of triamterene and amiloride on urinary sediment in hypertensive patients taking hydrochlorothiazide

In a crossover study of 26 hypertensive patients, the effects of triamterene (50 mg/day) and amiloride (5 mg/day) on urinary sediment were compared. Each drug was given for one month and all patients also received hydrochlorothiazide (50 mg/day). An abnormal urinary sediment--evident grossly as a reddish-brown precipitate after routine staining procedures and microscopically as characteristic reddish-brown crystals and casts, as previously described--was identified in 14 of 26 (54%) triamterene urine samples but in none of the amiloride samples. Results of renal function tests were similar for both drugs. In a clinic population of more than 1000 hypertensive patients over 4 years, interstitial nephritis was diagnosed in 4, all of whom were taking a triamterene-containing combination diuretic. It is possible that triamterene is a factor in the aetiology of interstitial nephritis.