Sulfonamide crystalluria: a forgotten disease

Alkalising agents in urinary tract infections: theoretical contraindications, interactions and synergy

Introduction:

Alkalising agents have the potential to enhance the efficacy of many antimicrobial agents used in the treatment of Urinary Tract Infections; they also have the potential to cause significant patient harm if used incorrectly. This work seeks to illustrate and quantify these risks and synergies by modelling drug solubility and supersaturation against pharmacokinetic data for commonly used antibiotic agents.

Methods:

Solubility-pH relationships are employed to quantify the crystalluria risk for compounds which may be reasonably expected to be co-prescribed—or co-administered—with urinary alkalisers (amoxicillin, nitrofurantoin, trimethoprim, sulfamethoxazole and ciprofloxacin). These results are correlated against reports of crystalluria in the literature and in the EU Adverse Drug Reaction database.

Results and Discussion:

We find a correlation between the maximum theoretical supersaturation attainable and crystalluria reports for sulfamethoxazole, amoxicillin and ciprofloxacin. Shifts in urine pH which can be induced by alkalising agents may produce supersaturated states (and thus induce crystalluria) and may also affect antimicrobial efficacy. The importance of employing biorelevant media to improve predictive capacity of this analysis is also discussed.

Conclusion:

Despite their widespread use, alkalising agents have significant effects on the pharmacokinetics of the most common drugs used to treat UTIs. With self-care set to increase, all OTC products should be critically re-evaluated to ensure patient safety, particularly within contexts where healthcare professionals are not involved in treatment selection. This analysis suggests a need for consistency across patient and healthcare professional documents to improve clarity.

Plain Language Summary

OTC Alkalising agents need additional warning information

Sulfamethoxazole-induced sulfamethoxazole urolithiasis: a case report

BACKGROUND

Drug-induced urolithiasis falls into two categories: drug-induced and metabolically-induced. Certain antimicrobials are associated with each; sulfonamides are associated with drug- or metabolite-containing calculi when taken in large doses over a long period of time. Trimethoprim-sulfamethoxazole, a member of the sulfonamide family, is a rare cause of drug-induced calculi. Cases of sulfonamide urolithiasis occurring in patients with known stone disease have rarely been reported.

CASE PRESENTATION

We report a case of a patient with a brief history of recurrent calcium oxalate nephrolithiasis requiring 2 ureteroscopic procedures whose existing 6 mm lower pole renal stone more than quadrupled in size to form a 4 cm renal staghorn after 4 months of high-dose treatment for Nocardia pneumonia with trimethoprim-sulfamethoxazole. After ureteroscopy with laser lithotripsy and basketing of fragments, the stone was found to be predominantly composed of N4-acetyl-sulfamethoxazole, a metabolite of sulfamethoxazole.

CONCLUSION

Stones composed of sulfamethoxazole or its metabolites are rare but have known associated risk factors that should be considered when prescribing this antibiotic. This case report illustrates additional risk factors for consideration, including pre-existing urinary calculi that may serve as a nidus for sulfamethoxazole deposition, and reviews treatment and prevention methods.

Sulphadiazine-induced obstructive renal failure complicating treatment of HIV-associated toxoplasmosis

A patient with newly-diagnosed HIV infection and biopsy-proven cerebral toxoplasmosis was treated with sulphadiazine and pyrimethamine. Despite adequate hydration and daily examination of urine for sulphadiazine crystals obstructive uropathy due to bilateral ureteric stones with hydronephrosis occurred, resulting in rapid onset renal failure. Sulphadiazine was discontinued and clindamycin was substituted. With intravenous fluid hydration and bilateral nephrostomies the urolithiasis resolved. This case serves to remind clinicians of the need for vigilance when treating cerebral toxoplasmosis with sulphadiazine, in order to avoid this potentially serious complication of treatment.

Approach to the Adult Kidney Stone Former

Nephrolithiasis is a prevalent and costly condition with high recurrence rate. A medical evaluation to identify abnormalities responsible for nephrolithiasis and guide subsequent therapy has been advocated to reduce the risk of stone recurrence. The evaluation of kidney stone formers generally comprises an extensive medical history to identify metabolic, environmental, dietary and/or genetic factors contributing to stone formation. Imaging studies are utilized to evaluate and follow stone burden. Laboratory studies including stone composition analysis and serum and urinary chemistries are commonly obtained to further assess for any underlying systemic disorders, to detect environmental and metabolic processes contributing to stone disease, and to guide initial and follow-up dietary and pharmacological therapy. The nature and extent of such an evaluation is discussed in this review article.

Acute renal failure due to sulphadiazine crystalluria in AIDS patients

We report two AIDS patients who developed acute renal failure while receiving sulphadiazine for cerebral toxoplasmosis. Renal ultrasound revealed diffuse bilateral echogenic shadowing material. 'Sheaves of wheat' crystals, typical of sulphadiazine crystalluria, were present in the urine. One patient required a percutaneous nephrostomy. Hydration and urine alkalinisation resulted in rapid improvement of renal function and ultrasonographic findings. Sulphadiazine-induced crystalluria and acute renal failure is increasingly frequent. Awareness of its existence may lead to prevention and early conservative treatment.

Sulfadiazine-associated nephrotoxicity in patients with the acquired immunodeficiency syndrome

We performed a computerized search on sulfadiazine-associated nephrotoxicity reported in human immunodefiency virus (HIV)-infected patients in the international literature. Including an original case report, we summarized 35 acquired immunodefiency syndrome (AIDS) patients from 1987 to 1995 in an analysis comparing their features to historical HIV-negative controls from the 1940s and 1950s. Likely due to a high prevalence of potential risk factors, incidence of sulfadiazine-associated renal impairment was 1.9%-7.5% in AIDS patients and 1%-4% in HIV-negative controls. Its occurrence appeared to be delayed in HIV-infected patients with a median of about 3 weeks of medication compared with about 10 days in HIV-negative subjects. Correspondingly, the cumulative sulfadiazine dose at manifestation doubled in AIDS patients with a median of 84 g versus 40 g in controls. Patients usually presented with flank or lumbar pain, oliguria, and (macro) hematuria. Urinalysis showed typical "sheaves of wheat" crystalluria, erythrozyturia, and, less commonly, leukozyturia and proteinuria. Echogenic (mostly peripelvic) densities, renal stones, and hydronephrosis are frequent findings on ultrasound examination, whereas X-ray examination possesses a low diagnostic sensitivity. The principle aim of therapy in these patients is to (re)institute the physicochemical urinary solubility of sulfadiazine and its metabolites. For this purpose, forced rehydration and, most importantly, urine alkalinization proved to be effective measures without an absolute need to withhold the drug. Provided prophylactic and therapeutic recommendations are complied with, outcome of this drug-related side effect is usually excellent, and rare relapses will similarly respond well.

Current recommendations and future prospects in the treatment of toxoplasmosis

Toxoplasma infection is highly prevalent throughout the world and causes disease in diverse populations. Effective treatment regimens are available for each clinical entity of toxoplasma, but problems of incomplete clinical efficacy, drug potency, drug safety, and length of treatment remain. No well-controlled clinical trials in humans have been performed to evaluate the efficacy and safety of treatment. Primary treatment of toxoplasmosis is with the synergistic combination of pyrimethamine and sulphonamide. This is considered the treatment of choice for severe disease, disease in immunocompromised patients, and congenital toxoplasmosis. Spiramycin, a macrolide antibiotic, is frequently used alone or alternately with pyrimethamine and sulphonamide for pregnant women with the acute acquired infection to prevent congenital toxoplasmosis. Clindamycin is used frequently to treat acute flares of toxoplasmic chorioretinitis and as second-line therapy for toxoplasmic encephalitis in patients with the acquired immunodeficiency syndrome (AIDS). Inadequacies in the treatment of toxoplasmosis in immunosuppressed patients, exemplified by experience with AIDS patients, should provide the impetus for well-designed trials to find and evaluate more potent and better-tolerated agents. Classes of new drugs that have been investigated and show some promise include: (a) macrolides (roxithromycin, azithromycin); (b) folic acid antagonists (piritrexim and trimetrexate), and (c) purine analogues (arprinocid). Immunomodulators have attracted interest, and interferon-gamma alone and in combination with roxithromycin is effective in murine models. Interleukin-2 is also effective in the murine model.

Sulfadiazine-associated obstructive nephropathy occurring in a patient with the acquired immunodeficiency syndrome

A 45-year-old man with the Acquired Immunodeficiency Syndrome (AIDS) and CNS toxoplasmosis presented with acute renal failure, hematuria, and renal colic shortly after starting treatment with sulfadiazine. Ultrasound examination of his kidneys was suggestive of intraparenchymal crystallization of sulfadiazine. His renal failure and ultrasound findings rapidly resolved with alkaline hydration. On rechallenge with sulfadiazine, he again developed renal insufficiency and ultrasonic findings consistent with stones. The use of sulfadiazine in the treatment of CNS toxoplasmosis in AIDS patients should be monitored carefully with the recognition that this form of crystalline-induced acute renal failure can occur in a dehydrated patient.

Acyclovir-induced renal failure. Clinical course and histology

Four patients with a chronic fatigue syndrome experienced five episodes of acute renal insufficiency associated with high-dose (500 mg/m2) intravenous acyclovir administered intravenously as one-hour infusions. Nephrotoxicity developed despite precautions to avoid volume contraction. Examination of the urinary sediment of three patients by polarizing microscopy showed birefringent needle-shaped crystals within leukocytes. In the most severely affected patient, a serum creatinine concentration of 8.6 mg/dl developed and the patient underwent percutaneous renal biopsy that revealed foci of interstitial inflammation without tubular necrosis. Urine, blood, and renal tissue levels of acyclovir were high. One patient was rechallenged with low-dose intravenous acyclovir and the four patients later received oral acyclovir, all without adverse effect. The combined data from these patients support crystalluria and obstructive nephropathy as a mechanism of acyclovir-induced renal failure in humans. This experience emphasizes the importance of maintaining adequate hydration during high-dose acyclovir therapy.

Crystalluria during flucytosine therapy

A case of urinary crystalluria occurring in a patient during treatment with flucytosine (5-fluorocytosine) is presented. A reduction in the dosage of the 5-fluorocytosine resulted in a marked decrease in the excretion of urinary gravel which was shown to be a coprecipitate of 5-fluorocytosine and uric acid.

Acute renal failure and hypoglycaemia due to sulphadiazine poisoning

A 3-year-old girl is described who became oliguric and hypoglycaemic whilst receiving an excessive dose of sulphadiazine. The mechanism of the hypoglycaemia is discussed.

Anuria due to sulphadiazine

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