Chapter 25 Disorders of Renal Function Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of Kidney Development • Renal agenesis • Renal hypoplasia • Renal dysplasia Copyright © 2015 Wolters Kluwer • All Rights Reserved Cystic Disorders • Genetic – Autosomal dominant polycystic kidney disease – Autosomal recessive polycystic kidney disease – Nephronophthisis – Medullary cystic kidney disease • Acquired – Simple cysts – Acquired form of renal cystic disease Copyright © 2015 Wolters Kluwer • All Rights Reserved Glomerulus • Glomerular capillaries and the Bowman capsule are both made of epithelial cells sitting on a basement membrane. • They are so tightly attached to each other that they share one basement membrane. • The epithelial cells of the Bowman capsule stand up from the basement membrane on foot processes, leaving pores between the feet for filtration. Copyright © 2015 Wolters Kluwer • All Rights Reserved Immune Mechanisms: Glomerular Disease Copyright © 2015 Wolters Kluwer • All Rights Reserved Glomerular Damage • Proliferative: number of cells increase. • Membranous: glomerular basement membrane thickens. • Sclerotic: amount of extracellular matrix increases. • All can decrease the efficiency of filtration. • Allow blood cells, lipids, or proteins to pass into the urine. Copyright © 2015 Wolters Kluwer • All Rights Reserved Question • True or false? • Nephritic syndromes are characterized by blood in the urine. Copyright © 2015 Wolters Kluwer • All Rights Reserved Answer • True • Rationale: Nephritic syndromes decrease the permeability of the glomerular capillary membrane, which results in hematuria, HTN, oliguria, and ↓ GFR. Copyright © 2015 Wolters Kluwer • All Rights Reserved Disorders of Glomerular Function • Acute nephritic syndromes • Rapidly progressive glomerulonephritis • Nephrotic syndrome • IgA nephropathy • Hereditary nephritis • Chronic glomerulonephritis Copyright © 2015 Wolters Kluwer • All Rights Reserved Nephritic Syndromes • Inflammatory process damages the capillary wall. – Hematuria with red cell casts, decreased GFR • Acute postinfectious glomerulonephritis. – Proliferative inflammatory response – Azotemia (presence of nitrogenous wastes in the blood), oliguria, cola-colored urine • Rapidly progressive glomerulonephritis. • Goodpasture syndrome. Copyright © 2015 Wolters Kluwer • All Rights Reserved Nephrotic Syndrome Copyright © 2015 Wolters Kluwer • All Rights Reserved Nephrotic Syndrome: Proteins in Urine • Albumin edema and increased free drug • Immunoglobulins and complement immune suppression • Binding proteins low ions and hormones • Clotting and anticlotting factors thrombosis Copyright © 2015 Wolters Kluwer • All Rights Reserved Scenario A woman with diabetes mellitus: • Has severe edema and frothy, cola-colored urine • Has difficulty breathing, with crackles in both lungs • Just finished a course of antibiotics for strep throat • Is taking corticosteroids for lupus-related arthritis Question: • What are three reasons for her renal problems? Copyright © 2015 Wolters Kluwer • All Rights Reserved Scenario (cont.) A woman: • Has diabetes mellitus and lupus • Recently had strep throat • Has severe edema and frothy, cola-colored urine Question: • The doctor says the only way to determine what has caused her glomerular disease is a renal biopsy. Why? Copyright © 2015 Wolters Kluwer • All Rights Reserved Scenario (cont.) • Urinalysis show that she is producing urine – With 500 mg protein/day – Containing blood and RBC casts – With high level of K+ • Blood tests show – Hypoalbuminemia and slightly decreased K+ • She has borderline hypertension Question: • Does she have nephritic syndrome or nephrotic syndrome? Copyright © 2015 Wolters Kluwer • All Rights Reserved Tubular and Interstitial Disorders • Acute tubular necrosis • Tubulointerstitial nephritis • Pyelonephritis – Acute pyelonephritis – Chronic pyelonephritis • Drug-related nephropathies Copyright © 2015 Wolters Kluwer • All Rights Reserved Chronic Pyelonephritis Copyright © 2015 Wolters Kluwer • All Rights Reserved Obstructive Disorders • Hydronephrosis • Renal calculi Copyright © 2015 Wolters Kluwer • All Rights Reserved Consequences of Dilation of the Renal Tubules or Tract • Expansion of the kidney with urine (hydronephrosis) – Increased pressure inside the renal capsule – Compartment syndrome compresses blood vessels inside kidney – Renal ischemia • Stasis of urine – Risk of infection – Stones Copyright © 2015 Wolters Kluwer • All Rights Reserved Question • True or false? • Hydronephrosis is categorized as a disorder of glomerular function. Copyright © 2015 Wolters Kluwer • All Rights Reserved Answer • False • Rationale: Hydronephritis is caused by a urinary obstruction, so it is considered an obstructive disorder. The glomerulus is not involved. Copyright © 2015 Wolters Kluwer • All Rights Reserved Renal Calculi • Saturation theory: Urine is supersaturated with stone components. • Matrix theory: Organic materials act as a nidus for stone formation. • Inhibitor theory: A deficiency of substances that inhibit stone formation. Copyright © 2015 Wolters Kluwer • All Rights Reserved Four Types of Renal Calculi • Calcium stones (i.e., oxalate or phosphate) • Magnesium ammonium phosphate stones • Uric acid stones • Cystine stones Copyright © 2015 Wolters Kluwer • All Rights Reserved Renal Calculi (cont.) Copyright © 2015 Wolters Kluwer • All Rights Reserved Malignant Kidney Tumors • Embryonic kidney tumors – That is, Wilms tumor, nephroblastoma – Childhood • Renal cell carcinoma – Adulthood Copyright © 2015 Wolters Kluwer • All Rights Reserved Wilms Tumor of the Kidney Copyright © 2015 Wolters Kluwer • All Rights Reserved Renal Cell Carcinoma of the Kidney Copyright © 2015 Wolters Kluwer • All Rights Reserved