Clinical Features and Investigations
Clinical features of UTI in patients with diabetes are essentially the same as in people without diabetes. Occasionally the fever may be less apparent, particularly in individuals with diabetic metabolic decompensation. Haematuria or flank pain secondary to sloughing papillae may be noted in patients with papillary necrosis. Occasionally patients may experience pneumaturia if gas has been produced within the urinary tract, or rarely gas in tissues may be palpated in flank or groin.
The investigation of possible UTIs in patients with diabetes requires urinalysis and urine culture, by catheterisation if necessary, prior to initiation of antimicrobial treatment. A blood culture should be routine in patients with presumed pyelonephritis. Due to increased incidence of local complications imaging is essential in patients with diabetes and acute pyelonephritis. An abdominal X-ray may help exclude renal emphysema. Ultrasound or CT should be considered for all septic patients. Although intravenous and retrograde pyelograms, ultrasonography and nuclear imaging techniques all have played a role, CT scanning has become the preferred modality.[41,42,43]
Helical CT scan provides an excellent view of the organs and can identify inflamed renal parenchyma, exclude obstruction and identify renal calculi. Contrast enables a more accurate recognition of acutely inflamed renal tissue and identifies air or pus in tissue with increased sensitivity and specificity. It also characterises renal infection as focal or diffuse. However, the use of radio-contrast may lead to concerns in patients with diabetes due to risks of transient or occasionally permanent loss of renal function. Extra care should be exercised in type 2 diabetic patients on metformin receiving contrast media, due to risks of lactic acidosis consequent to reduced clearance of the drug. According to the Royal College of Radiologists no special precaution is needed if the serum creatinine is normal, and low volume contrast agent is to be administered. If more than 100 ml of contrast agent or an intra-arterial route is to be used, metformin should be withheld for 48 h after the procedure. If serum creatinine is raised, the need for contrast should be assessed and if it is deemed necessary, metformin should be withheld for 48 h before and after the contrast study. However, with careful fluid management, most patients with diabetes would be able to tolerate low ionic contrast media.[4,41–43]
British Journal of Diabetes and Vascular Disease. 2009;9(3):119-125. © 2009 Sage Publications, Inc.
Cite this: Diversity and Complexity of Urinary Tract Infection in Diabetes Mellitus - Medscape - May 01, 2009.