Renal vasculitis associated with ciprofloxacin

Ceftriaxone-induced leukocytoclastic vasculitis: a case report and literature review of antibiotic-induced leukocytoclastic vasculitis

Leukocytoclastic vasculitis (hypersensitivity vasculitis) is defined as small blood vessel inflammation with skin or other systemic manifestations due to infections, drugs, or neoplastic disease. This clinical case report highlights an association between ceftriaxone and leukocytoclastic vasculitis in a 49-year-old female patient with a history of penicillin allergy, on mirtazapine for anxiety disorder. Articles concerning antibiotic-induced leukocytoclastic vasculitis are also reviewed. The patient reported a symptom of upper respiratory tract infection and fever 5 days previously for which she received ceftriaxone for 2 days before presenting to the emergency department with a pruritic skin rash in the upper and lower extremities and swollen lips for 1 day. The rash was erythematous, maculopapular, itchy, and non-tender, with no mucus membrane involvement. Laboratory investigations revealed leukocytosis (white blood cells, 22.3 × 10⁹/L) that was mainly eosinophilic (18.4%). The patient was administered prednisolone and antihistamine after stopping ceftriaxone empirically. A skin biopsy confirmed the diagnosis of leukocytoclastic vasculitis. Significant clinical improvement was observed after treatment initiation. Upon follow-up, the skin rash was resolved entirely with no scars; however, there was skin-peeling over the lower extremities. Recognition of antibiotic-induced leukocytoclastic vasculitis is crucial as many classes of antibiotics can contribute to this condition. Continuation of the offending drug may lead to life-threatening complications.

Acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody following cimetidine treatment: a case report

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis usually induces rapidly progressive glomerulonephritis, including pauci-immune necrotizing crescentic glomerulonephritis. Acute tubulointerstitial nephritis (ATIN), which is often drug-induced, is a frequent cause of kidney injury. However, ATIN associated with ANCA without any glomerular lesions has been rarely reported, and drug-induced ATIN associated with ANCA is not well recognized. Here we present a case of an older woman with ATIN associated with myeloperoxidase-ANCA (MPO-ANCA) following cimetidine treatment.

Case presentation

A 70-year-old woman was admitted to our hospital due to acute kidney injury and mild proteinuria. She had a one-year history of chronic thyroiditis and dyslipidemia, for which she was taking levothyroxine sodium and atorvastatin, respectively. Two weeks before admission she had started cimetidine, methylmethionine sulfonium chloride, and itopride hydrochloride for gastric discomfort persistent since a month. She had experienced fatigue for two weeks and later appetite loss. The patient demonstrated a positive titer for MPO-ANCA (192 IU/mL) and a positive drug-induced lymphocyte stimulation test for cimetidine. She underwent two kidney biopsies that revealed ATIN without any glomerular lesions. Despite discontinuation of cimetidine on admission, renal injury continued with the presence of high MPO-ANCA titer. Oral steroid treatment was closely related with the recovery of her renal function and disappearance of MPO-ANCA.

Conclusions

In this case, ATIN presented as sustained renal insufficiency and high MPO-ANCA titer despite withdrawal of cimetidine. Therefore, we reason that the development of ANCA-associated ATIN was caused by cimetidine. Serologic follow-up with measurement of MPO-ANCA titers and renal biopsy are recommended when the clinical history is inconsistent with the relatively benign course of drug-induced ATIN.

Nephrotoxicity of Ciprofloxacin: Five Cases and a Review of the Literature

Fluoroquinolones are usually well tolerated with a minimum of serious adverse effects; renal toxicity is uncommon. Apart from the renal side effects of ciprofloxacin, we aimed to highlight the renal impact of a ciprofloxacin overdose, and thus conducted a prospective study in the Department of Nephrology at La Rabta Hospital between 2010 and 2015. The cohort database was continually updated until the inclusion of five patients who were subjected to an overdose and who were initially admitted to the medical intensive care unit and then transferred to our department for acute renal failure (ARF) due to ciprofloxacin ingestion requiring urgent hemodialysis. All patients developed ARF after 12–36 h of ingestion. Renal ultrasound was normal in all cases. Twenty-four-hour proteinuria was present but not significant in one case, while microscopic hematuria was present in one case. Treatment consisted of supportive therapy and extrarenal purification by conventional intermittent hemodialysis. Four patients recovered normal renal function within 3 weeks and the remaining patient eventually had chronic kidney failure.

Clinical Manifestations and Outcomes of Fluoroquinolone-Related Acute Interstitial Nephritis

OBJECTIVE

To describe the clinical presentation, diagnosis, and outcomes of patients with biopsy-proven acute interstitial nephritis (AIN) related to fluoroquinolone (FQ) therapy.

PATIENT AND METHODS

We conducted a retrospective review of biopsy-proven AIN attributed to FQ use at Mayo Clinic's campus in Rochester, Minnesota, from January 1, 1993, through December 31, 2016. Cases were reviewed by a renal pathologist and attributed to FQ use by an expert nephrologist. We also reviewed and summarized all published case reports of biopsy-proven AIN that were attributed to FQ use.

RESULTS

We identified 24 patients with FQ-related biopsy-proven AIN at our institution. The most commonly prescribed FQ was ciprofloxacin in 17 patients (71%), and the median antibiotic treatment duration was 7 days (interquartile range [IQR], 5-12 days). The median time from the initiation of FQ to the diagnosis of AIN was 8.5 days (IQR, 3.75-20.75 days). Common clinical manifestations included fever (12; 50%), skin rash (5; 21%), and flank pain (2; 8%), and 9 (38%) had peripheral eosinophilia. However, 4 (17%) of the patients were asymptomatic at the time of diagnosis and AIN was suspected on the basis of routine laboratory monitoring. Most patients (17; 71%) recovered after the discontinuation of antibiotic therapy, and renal function returned to baseline at a median of 20.5 days (IQR, 11.75-27.25 days). Six patients (25%) required temporary hemodialysis, and 14 patients (58%) received corticosteroid therapy.

CONCLUSION

The onset of FQ-related AIN can be delayed, and a high index of suspicion is needed by physicians evaluating these patients. Overall outcomes are favorable, with recovery to baseline renal function within 3 weeks of discontinuing the offending drug.

Pauci-immune crescentic glomerulonephritis associated with use of trimethoprim-sulfamethoxazole

Drug-induced pauci-immune crescentic glomerulonephritis has been described with several agents, including propylthiouracil, minocycline, D-penicillamine, and hydralazine. We present the case of a 60-year-old man who presented with rapidly progressive glomerulonephritis in the setting of recent use of trimethoprim-sulfamethoxazole complicated by the development of the Stevens-Johnson syndrome, and was found to have biopsy-proven pauci-immune crescentic glomerulonephritis and undetectable anti-neutrophilic cytoplasmic antibodies. We review the existing literature on the potential association between sulfonamides and hypersensitivity polyangiitis.

Resolution of anti-neutrophil cytoplasmic antibody-associated vasculitis after resection of gastric cancer

We report a case of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis in a 62-year-old patient with gastric cancer. The myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) level was threefold above normal preoperatively. Vasculitis was seen on renal biopsy. Gastric resection revealed well-differentiated adenocarcinoma and vasculitis. The MPO-ANCA level returned to normal post-operatively. Although ANCA-associated vasculitis occasionally accompanies malignant tumors, this is the first documented case of concurrent gastric cancer-associated and ANCA-associated vasculitis, with post-operative resolution of the vasculitis.

Cutaneous vasculitis associated with fluoroquinolones

Cutaneous vasculitis is a clinical entity with a broad differential diagnosis, including an adverse drug reaction. It is defined as inflammation of skin blood vessel walls. During a 7-year-period, we observed three patients who developed isolated cutaneous vasculitis during antibiotic therapy of bacterial infection. All were treated with a fluoroquinolone (ciprofloxacin or levofloxacin) combined with rifampin (two cases) or flucloxacillin (three cases), respectively. In all three cases the lesions gradually resolved after treatment with the inciting fluoroquinolone had been stopped. In one patient, leukocytoclastic small-vessel vasculitis was histologically confirmed. Fluoroquinolone-associated cutaneous vasculitis consists of an isolated self-limiting disorder that is part of a systemic vasculitis, or even life-threatening disease. Clinicians should be aware of this serious adverse event because any continuation of treatment may be fatal.

Tubulointerstitial nephritis without glomerular lesions in three patients with myeloperoxidase-ANCA-associated vasculitis

BACKGROUND

Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis frequently induces crescentic glomerulonephritis. However, a few cases have so far been reported to have only tubulointerstitial (TI) nephritis without any apparent glomerular lesions. We recently treated three similar cases. Therefore, their pathological features as well as clinical manifestations were studied in detail.

METHODS

The pathological study was performed with immunohistochemical staining using various antibodies to the vascular endothelial cell surface markers, von Willebrand factor, type IV collagen, cytokeratin, E-cadherin, and MPO in addition to the routine histochemical examination.

RESULTS

The study disclosed the loss of CD34 endothelial cell surface markers with and without the destruction of type IV collagen (capillary basement membrane) in the peritubular capillaries, even though the glomeruli showed good staining of these factors. Electron microscopy showed breaks in the capillary basement membrane. The loss of CD34 staining was associated with the infiltration of a few mononuclear cells and neutrophils in the lumen of peritubular capillaries and the surrounding interstitial tissues. The cytokeratin staining in the tubular epithelial cells was also diminished around these areas. Tubulitis was demonstrated with or without the destruction of the tubular basement membrane. The clinical manifestations of these three cases were only a few red blood cells and granular casts in the urinary sediment as well as slightly increased beta2-microglobulin in the urine, but no proteinuria.

CONCLUSION

Based on these findings, the loss of CD34 vascular endothelial markers occurs in the early phase of the disease because of the MPO, which is presumed to have burst out from the infiltrated, activated neutrophils. This MPO, which releases proteolytic enzymes and radical oxygen species, acts on tissue destruction, namely the lysis of endothelial cell membranes as well as vascular basement membranes in the peritubular capillary. This mechanism eventually proceeds to the destruction of the peritubular capillary walls (vasculitis). This pathogenesis is thought to play an important role in the pathogenesis of TI nephritis, which is associated with MPO-ANCA vasculitis.

Drug-induced Kidney Disease – Pathology and Current Concepts

The kidneys can be damaged by a large number of therapeutic agents. The aim of this article is to discuss the pathological features of drug-induced renal disease as diagnosed by kidney biopsy. The literature is reviewed and cases seen by the authors that have a known drug association are analysed. Mechanisms of injury are varied and all renal structures may be affected. The tubulointerstitial compartment is most frequently involved, but glomerular and vascular lesions are seen in a significant proportion of cases. Key words: Drug, Kidney, Nephrotoxicity, Pathology

Cimetidine-induced tubulointerstitial nephritis with both MPO-ANCA and PR3-ANCA

We describe a 75-year-old man with tubulointerstitial nephritis (TIN) with myeloperoxidase (MPO)-antineutrophil antibody (ANCA) and proteinase-3 (PR3)-ANCA. He had a slight fever and eruption with itching after taking cimetidine (prescribed after gastrectomy for gastric cancer) and he was admitted to a nearby hospital. There, he showed proteinuria, serum creatinine (sCr) of 2.9 mg/dl, and creatinine clearance (Ccr) of 44 ml/min per 1.73 m2. His MPO-ANCA titer was 267 EU, and PR3-ANCA titer was 112 EU. Abnormal concentrations in bilateral kidneys were found by gallium scintigraphy. For these reasons, he was transferred to our hospital. Percutaneous renal biopsy was performed after admission. Severe tubular atrophy, mild interstitial fibrosis, and severe mononuclear cell infiltration of the interstitium were noted. Drug-induced renal impairment was suspected, and cimetidine administration was withdrawn. Lymphocyte stimulation tests (DLSTs) were performed. The cimetidine titer was positive, at 2,537 cpm. After the withdrawal of cimetidine, the PR3-ANCA titer was reduced gradually, and, next, the MPO-ANCA titer was also reduced. The sCr level was reduced to 1.2 mg/dl. In summary, we report herein the first case of cimetidine-induced TIN associated with both MPO-ANCA and PR3-ANCA.

Les insuffisances rénales aiguës aux quinolones. Revue générale à propos d'une observation avec cristallisation liée à la ciprofloxacine

A 58 year-old woman developed an acute renal failure very quickly after ingestion of two 500 mg tablets of ciprofloxacin, without any other identifiable risk factor. Renal biopsy was performed. No sign of acute interstitial nephritis was observed but tubular lesions were found, accompanied by deposits of a brown-yellowish substance identified by infrared microscopy as a ciprofloxacin salt. The outcome was favourable. This observation gives the opportunity to remind the different forms of quinolone-induced renal injury and to discuss the possible ways for preventing renal side-effects related to the quinolone use.

Antineutrophil cytoplasmic antibody positive alveolar haemorrhage during propylthiouracil therapy for hyperthyroidism

Recently, propylthiouracil (PTU) has been thought to be one of the possible causes of antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis syndrome, resulting in glomerulonephritis and, infrequently, diffuse alveolar haemorrhage (DAH). The mechanism of ANCA-positive vasculitis during PTU therapy is still unknown. Herein, we describe the case of a 59-year-old woman who developed myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA positive DAH, without any other organ system involvement, during PTU therapy. Diminution and discontinuation of PTU resulted in a positive response. To our knowledge, this is the first documentation of both MPO- and PR3-ANCA-positive DAH, without systemic manifestations, developing during PTU therapy.

Quinolone hypersensitivity

PURPOSE OF REVIEW

Quinolones are potent antibacterial agents that can cause drug hypersensitivity reactions affecting different organs. A better understanding of the underlying mechanism and the level of crossreactivity within different quinolones is needed to handle and prevent these diseases.

RECENT FINDINGS

The adverse side-effects caused by quinolones are the result of different immunological mechanisms and cause quite different diseases. The development of an assay detecting quinolone-specific IgE revealed specific antibodies in more than 50% of patients with immediate-type reactions, and the majority of sera also reacted with related compounds. In maculopapular drug exanthemas caused by ciprofloxacin, specific T cells could be detected and cloned. They reacted with ciprofloxacin directly, and crossreactivity to related compounds was detected in approximately 50% of the clones.

SUMMARY

Quinolones can cause drug hypersensitivity reactions by different immunological mechanisms. In-vitro analysis suggests that crossreactivity is common.

Nephrotoxicity and purpura associated with levofloxacin

OBJECTIVE

To report a patient with lung cancer and idiopathic myelofibrosis with myeloid metaplasia who developed purpura and acute renal failure while receiving levofloxacin, and review the existing literature on quinolone nephrotoxicity.

CASE SUMMARY

A 73-year-old white man, with a medical history of non-small-cell lung cancer and idiopathic myelofibrosis with myeloid metaplasia, was prescribed levofloxacin because of a lower urinary tract infection. Three days later, he presented with palpable purpura and erythematous skin lesions over the lower limbs and trunk, with a markedly reduced urinary output. Serum creatinine and urea nitrogen were 6.4 and 190 mg/dL, respectively. Levofloxacin was discontinued, and prednisone, furosemide, and intravenous fluids were given. The patient fully recovered over the ensuing 4 weeks.

CONCLUSIONS

Nephrotoxicity associated with levofloxacin is uncommon. Allergic interstitial nephritis or vasculitis is believed to be the underlying pathologic process. Definitive diagnosis requires performance of renal biopsy, although this is not always feasible. In this case, a return of renal function to normal, with the disappearance of purpura following the discontinuation of levofloxacin and corticosteroid treatment, supports the presumptive diagnosis of a hypersensitivity reaction to levofloxacin.

Cutaneous and systemic manifestations of drug-induced vasculitis

OBJECTIVE

To evaluate the literature for published cases of drug-induced vasculitis with cutaneous and/or systemic manifestations.

DATA SOURCES

The MEDLINE database was searched from 1965 to December 1999 for articles focusing on drugs and vasculitis, using various search terminologies (e.g., Churg-Strauss syndrome, Goodpasture's syndrome, Henoch-Schönlein purpura, various drugs suspected to induce vasculitis). Cases were included when they met the established criteria as described in the methodology.

DATA SYNTHESIS

Drugs found to be most frequently associated with vasculitis were propylthiouracil, hydralazine, colony-stimulating factors, allopurinol, cefaclor, minocycline, D-penicillamine, phenytoin, isotretinoin, and methotrexate. The interval between the first exposure and appearance of symptoms was reported to be extremely variable (hours to years). Vasculitis has occurred after drug dosage increases and after rechallenge with the suspected drug. In the majority of cases, vasculitis has resolved after discontinuing the drug. Patients with more severe, often life-threatening, manifestations have required treatment with corticosteroids, plasmapheresis, hemodialysis, or cyclophosphamide. Death was the result in 10% of all published cases, with a predominance in patients in whom multiple organ systems were involved.

CONCLUSIONS

Clinicians need to be suspect of drug-induced vasculitis to enable prompt diagnosis and treatment. This should improve patient outcomes based on the data referenced for this article.

Drug-induced vasculitis

DIV is a relatively common cause of inflammatory vasculitis. Drugs from almost every pharmacologic class have been implicated in causing vasculitis in sporadic cases. The level of certainty and quality of evidence for these associations between specific agents and vasculitis vary greatly. The clinical manifestations of DIV range from single organ involvement (most commonly, skin) to life-threatening multiorgan disease. The recently described subset of cases of DIV associated with positive tests for ANCA are an interesting subset of DIV. The diagnosis of DIV is usually one of exclusion. The treatment of DIV is dependent on the severity of disease activity but should always include withdrawal of the suspected drug. If no agent can be implicated, as many drugs as feasible should be discontinued. The necessity of prescribing glucocorticoids or immunosuppressive agents depends on the disease severity and other case-specific information. Increasing understanding of the pathophysiologic characteristics of all inflammatory vasculitides should lead to better diagnostic and therapeutic approaches to DIV.

Renal Vasculitis Associated with Doxycycline

Objective:

To report a case of renal small-vessel vasculitis related to doxycycline administration.

Case Summary:

A 42-year-old healthy woman was given doxycycline 100 mg/d because of a fever and a cough. Two days later, she developed a fever and rash. In addition, she deveoped acute renal failure with a creatinine concentration of 2.2 mg/dL and a glomerular filtration rate of 25 mL/min, as well as an increase in liver enzymes. No evidence was found for infectious or autoimmune etiologies. Renal biopsy showed renal small-vessel vasculitis. The patient was treated with prednisone 60 mg/d for one month. All of her symptoms resolved after three months.

Conclusions:

This is a unique case of isolated renal vasculitis associated with doxycycline.

Nephrotoxicity and hepatotoxicity of histamine H2 receptor antagonists

The extensive use of selective histamine H2 receptor antagonists provides a unique opportunity to describe very rare adverse drug reactions. Although mild elevation of serum creatinine level following the administration of cimetidine is relatively common, acute interstitial nephritis (AIN) is a rare hypersensitivity reaction. There have been 25 published reports of AIN associated with H2 antagonist therapy and we also identified 16 cases from the Australian Adverse Drug Reaction Advisory Committee (ADRAC) database. AIN was reported most commonly following cimetidine administration. AIN was supported by renal biopsy in 28 patients and by rechallenge in 6. H2 antagonist-induced AIN was more commonly reported in men older than 50 years. In the majority of cases the onset was within 2 weeks of initiation of therapy (1 day to 11 months). The clinical manifestations were nonspecific including sterile pyuria, elevated erythrocyte sedimentation rate, fatigue, proteinuria and leucocytosis whereas rash, arthralgia and flank pain were rarely reported. There were 170 cases of hepatotoxicity following H2 antagonist administration reported to ADRAC. These were more common following ranitidine and included cholestatic, hepatocellular and mixed reactions. Hepatotoxicity was proven following liver biopsy in several cases published in the literature and in 15 cases reported to ADRAC. Hepatotoxicity recurred upon rechallenge in 6 cases. Generally, renal and hepatic adverse effects resolved quickly after cessation of H2 antagonist therapy and did not require specific treatment. Nephrotoxicity and hepatotoxicity following administration of an H2 antagonist is rare and a high index of suspicion is necessary for early detection. Now that many H2 antagonists are available over the counter, awareness of these conditions and early detection with cessation of H2 antagonist therapy would appear paramount.

Evaluation of antineutrophil cytoplasmic antibody seroconversion induced by minocycline, sulfasalazine, or penicillamine

OBJECTIVE

Case reports have suggested that minocycline, sulfasalazine, and penicillamine are associated with antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. This study evaluated ANCA seroconversion due to these agents in serum samples prospectively collected in randomized, double-blind, controlled trials.

METHODS

The sources of study sera were 3 clinical trials: 1) a 48-week trial of minocycline for early rheumatoid arthritis, with 64 patients receiving minocycline compared with 68 receiving placebo; 2) a 37-week trial of sulfasalazine for rheumatoid arthritis, with 51 receiving sulfasalazine compared with 38 receiving placebo; and 3) a 104-week trial of penicillamine for early systemic sclerosis, with 15 undergoing high-dose penicillamine treatment versus 12 receiving low-dose penicillamine. ANCA were measured in the baseline and study-end serum samples by indirect immunofluorescence (IIF) for perinuclear ANCA (pANCA) and cytoplasmic ANCA (cANCA) patterns, and by antigen-specific enzyme-linked immunosorbent assay (ELISA) for antibodies to myeloperoxidase (anti-MPO) and proteinase 3 (anti-PR3). Laboratory personnel were blinded to the group identity of the samples. ANCA results were interpreted using an ANCA scoring system that combines the results of IIF and ELISA testing.

RESULTS

No patient in any of the active study drug groups demonstrated ANCA seroconversion according to the final interpretation of the combined IIF and ELISA results. Twelve of the 248 patients (5%) were positive for anti-MPO with pANCA at baseline. No subject was positive for anti-PR3 with cANCA. There were no findings suggestive of vasculitis in any of these patients.

CONCLUSION

From our study results, there was no suggestion of ANCA seroconversion induced by minocycline, sulfasalazine, or penicillamine. However, these findings do not rule out the possibility of rare, sporadic cases of either ANCA seroconversion or true drug-induced vasculitis with these drugs.

Fluoroquinolone-induced renal failure

Fluoroquinolones are generally well tolerated, clinically useful antimicrobials. This paper highlights rare, but potentially serious, adverse effects involving the kidney. Other antimicrobials have long been known to cause various forms of nephrotoxicity occurring as allergic interstitial nephritis, granulomatous interstitial nephritis, necrotising vasculitis, allergic tubular nephritis or a tubular necrosis. A Medline search (1985 to May 1999) of ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, trovafloxacin, enoxacin, sparfloxacin, grepafloxacin, gatifloxacin, clinafloxacin and moxifloxacin was conducted to ascertain the incidence and features of fluoroquinolone nephrotoxicity. Unfortunately, the data primarily consist of case reports and temporally related events. The incidence of these adverse effects is hard to estimate, and the cause may be multifactorial. While the use of ciprofloxacin appears to increase the risk, this may be due to its longer and more widespread use when compared with the newer agents.

Cephotaxime-associated allergic interstitial nephritis and MPO-ANCA positive vasculitis

We report a case of reversible acute renal failure after cefotaxime treatment in a patient affected by non-Hodgkin lymphoma. Renal biopsy showed necrotizing vasculitis associated with eosinophil-rich interstitial inflammatory infiltrates and patchy infiltrates of CD20+ lymphoid cells. High serum p-ANCA titers were also detected. Drug withdrawal was closely related with recovery of renal function and disappearance of ANCA. Acute renal failure therefore represented a consequence of ANCA-mediated renal vasculitis and acute interstitial nephritis related to cefotaxime treatment.

A case of cimetidine-induced acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody

We present a case of acute tubulointerstitial nephritis (ATIN) that developed in a 63-year-old man who had been taking cimetidine for treatment of a gastric ulcer. The constellation of clinical, laboratory, and histopathologic findings suggested drug-induced ATIN. Of interest, the patient had antineutrophil cytoplasmic antibody (ANCA) in his sera, reactive with myeloperoxidase, elastase, and lactoferrin. Prominent renal histological features included marked plasmacyte infiltration into the renal interstitium. Withdrawal of cimetidine resulted in complete resolution of renal findings, and the titers of ANCA concomitantly declined. Thus, cimetidine may have played a causative role in the development of ANCA-associated ATIN.

Wegener's granulomatosis in a patient with apparent drug-induced acute interstitial nephritis

We describe a patient whose clinical presentation was suggestive of drug-induced acute interstitial nephritis (AIN). A renal biopsy and serologic testing led instead to the diagnosis of Wegener's granulomatosis (WG) with necrotizing crescentic glomerulonephritis. Treatment with corticosteroids and cyclophosphamide resulted initially in complete recovery of renal function, and an exacerbation of acute renal failure after doses of these agents had been tapered responded to resumption of the original regimen. We report this case to emphasize the potentially identical presentations of AIN and WG. Since the two conditions are treated differently, we suggest that the diagnosis of AIN should be accepted only after biopsy confirmation.