Chapter 33: Disorders of Renal Function

The comprehensive overview of kidney function disorders begins by detailing developmental and genetic abnormalities such as renal agenesis, hypoplasia, and dysplasia, including the various forms of inherited cystic kidney diseases like Autosomal Dominant and Recessive Polycystic Kidney Disease (ADPKD and ARPKD). The chapter then pivots to obstructive uropathies, focusing on the destructive effects of urine stasis and progressive dilation, particularly hydronephrosis, and thoroughly examining the common etiology of renal calculi (kidney stones), including the roles of urine supersaturation, crystal nucleation, and specific stone compositions such as calcium, struvite, uric acid, and cystine. A significant section addresses Urinary Tract Infections (UTIs), examining host defense mechanisms like the washout phenomenon against pathogen virulence factors, noting the critical role of obstruction and vesicoureteral reflux, and highlighting unique risks and clinical manifestations in special populations, including pregnant women, children, and older adults. Moving inward to the filtering structures, glomerular diseases are categorized into clinical syndromes—the nephritic syndromes (characterized by inflammation, hematuria, and decreased GFR) and the nephrotic syndrome (marked by massive proteinuria and generalized edema)—as well as complications arising from systemic conditions such as Systemic Lupus Erythematosus (SLE), diabetes mellitus (diabetic glomerulosclerosis), and hypertension (nephrosclerosis). Finally, the chapter concludes by covering tubulointerstitial diseases, specifically Proximal and Distal Renal Tubular Acidosis (RTA), acute and chronic pyelonephritis, drug-related nephropathies, and a review of malignant tumors, including Wilms tumor in children and adult renal cell carcinoma, discussing their respective etiologies and treatment modalities.