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Chapter 25
Disorders of Renal Function
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cystic and Obstructive Disorders
• Cystic disease of the kidney
– Simple and acquired renal cysts
– Medullary cystic disease
– Autosomal dominant polycystic kidney
disease
• Obstructive disorders
– Hydronephrosis
– Renal calculi
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Consequences of Dilatation of 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 © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false:
Hydronephrosis is categorized as a disorder of glomerular
function.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
False
Hydronephritis is caused by a urinary obstruction, so it is
considered an obstructive disorder. The glomerulus is
not involved.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
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
• Four types of kidney stones:
– Calcium stones (i.e., oxalate or phosphate)
– Magnesium ammonium phosphate stones
– Uric acid stones
– Cystine stones
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Urinary Tract Infections
• Bacteria usually enter through the urethra
• Host defenses include:
– Washout phenomenon
– Protective mucus
– Local immune responses and IgA
– Normal bacterial flora
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Scenario
Mr. K is paraplegic…
• When in the hospital, he had a catheter
• Now he has a high fever and complains of joint and back
pain
• He has pyuria and reports urgency
• BUN is 78 mg/dL
• PCR is 4.7 mg/dL
Question:
• What complication are you most worried about? Why?
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false:
UTIs are usually caused by a virus.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
False
UTIs are most often caused by bacteria that enter through
the urethra (most common) or the bloodstream.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
• Glomerular capillaries and
Bowman’s 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
Bowman’s capsule stand up
from the basement
membrane on foot
processes, leaving pores
between the feet for filtration
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Glomerular Damage
• Proliferative: number of cells increase
• Sclerotic: amount of extracellular matrix
increases
• Membranous: thickness of glomerular
capillary wall increases
• All can decrease the efficiency of filtration
• Allow blood cells, lipids, or proteins to pass
into the urine
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Disorders of Glomerular Function
• Nephritic syndromes
– Proliferative inflammatory response
• Nephrotic syndrome
– Increased permeability of glomerulus
• Mixed nephritic and nephrotic responses
• Chronic glomerulonephritis
• Glomerular lesions associated with systemic
disease
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Nephritic Syndromes
• Proliferative inflammatory response
– RAA pathway activated; hypertension
• Inflammatory process damages the capillary wall
– Red blood cells escape into the urine
• Hematuria with red cell casts
– Hemodynamic changes decrease the GFR
• Azotemia (presence of nitrogenous wastes in the
blood), oliguria
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Nephrotic Syndrome
• Other proteins lost in urine:
Immunoglobulins and
complement  immune
suppression
Clotting and anticlotting
proteins  thrombosis
Proteins that carry other
blood components 
imbalances in blood
components; altered drug
dosages
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Tell whether the following statement is true or false:
Nephritic syndromes are characterized by blood in the
urine.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
True
Nephritic syndromes decrease the permeability of the
glomerular capillary membrane, which results in
hematuria, HTN, oliguria, and ↓ GFR.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Scenario
A woman has diabetes mellitus…
• She has severe edema and frothy, cola-colored
urine
• She has difficulty breathing, with crackles in both
lungs
• She just finished a course of antibiotics for strep
throat
• She is also taking corticosteroids for lupus-related
arthritis
Question:
• What are three reasons for her renal problems?
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Scenario (cont.)
A woman has diabetes mellitus and lupus and
recently had strep throat…
• She has severe edema and frothy, colacolored urine
Question:
• The doctor says the only way to determine
what has caused her glomerular disease is a
renal biopsy. Why?
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Scenario (cont.)
• Urinalysis show that she is producing:
– Urine with 500 mg protein/ day
– Contains blood and RBC casts
– High level of K+
• Blood tests show:
– Hypoalbuminemia
– Slightly decreased K+
• She has borderline hypertension
Question:
• Does she have nephritic syndrome or nephrotic
syndrome?
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Tubulointerstitial Disorders
• Acute tubular necrosis
• Pyelonephritis
– Acute pyelonephritis
– Acute hypersensitivity to drugs
– Chronic pyelonephritis
• Drug-related nephropathies
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Malignant Tumors of the Kidney
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins