Diabetes mellitus

Insulin is required for many of the metabolic steps in glucose utilization, and diabetes is characterized by insufficient insulin action at the cellular level. In type I DM, there is an absolute decrease in the amount of insulin. In type II DM, peripheral resistance to insulin prevents its proper functioning. Hyperglycaemia results, associated with osmotic diuresis when the degree of hyperglycaemia exceeds the kidney's capacity for tubular reabsorption of glucose.

The clinical triad of symptoms at presentation involves: polydipsia, polyphagia and polyuria. An acute crisis can be precipitated by ketoacidosis or a hyperosmolar state. Chronic complications include diabetic nephropathy, neuropathy and retinopathy. Chronic hyperglycaemia also results in impaired immune response and predisposes the patient to infections. Vascular insufficiency further prevents proper healing and repair in the presence of infection. Treatment consists of insulin, oral hypoglycaemic agents, and dietary and weight control.

The manifestations of diabetes in the genitourinary system are diverse, and most of them can be diagnosed through radiological imaging. The chronic effects include: diabetic nephropathy, papillary necrosis, renal artery stenosis, diabetic cystopathy and vas deferens calcification. Infectious complications include renal and perirenal abscesses, gas-forming infections such as emphysematous pyelonephritis and emphysematous cystitis, fungal infections and xanthogranulomatous pyelonephritis. Genital infections are also encountered with a higher frequency than in the non-diabetic general population, and these include Fourniers gangrene and tubo ovarian abscess.

Please see specific entries for specific imaging features. In general, CT serves as a useful starting point for imaging manifestions of diabetes in the genitourinary tract. In everyday clinical work, one should keep in mind the risk of contrast-induced nephropathy in the diabetic patient.

HH