Essentials of Pathophysiology
CHAPTER 25
DISORDERS OF RENAL FUNCTION
PRE LECTURE QUIZ TRUE/FALSE
F

F

T

T

T
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The kidneys do not begin to develop until the 12th
week of gestation and start to function
approximately 6 weeks later.
There is just a single theory that applies to kidney
stone formation.
Most uncomplicated urinary tract infections (UTIs)
are caused by Escherichia coli.
Upper urinary tract infections differ from those of
lower urinary tract infections in that they incite an
acute inflammatory response with marked systemic
manifestations of infection.
Catheter-associated bacteriuria remains the most
frequent cause of gram-negative septicemia in
hospitalized patients.
PRE LECTURE QUIZ
calcium

Autosomal dominant polycystic kidney disease
(ADPKD) is a systemic disorder that primarily affects
the kidneys, resulting in the formation of fluid-filled
__________ in both kidneys with the threat of
progression to chronic renal failure.

____________ refers to urine-filled dilatation of the
renal pelvis and calices associated with progressive
atrophy of the kidney due to obstruction of the outflow
of urine.

Most kidney stones are composed of __________.

Nephrotic syndrome is associated with increased
glomerular permeability to the plasma __________,
resulting in generalized edema.

The __________ phenomenon, the process by which
the urine released from the bladder washes out the
bacteria out of the urethra, aids in maintaining the
sterility of the urine formed in the kidneys and found in
the bladder.
Hydronephrosis
protein
sacs
washout
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
CONSEQUENCES OF DILATION 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
HYDRONEPHROSIS
QUESTION
Tell whether the following statement is true or
false.
Hydronephrosis is categorized as a disorder of
glomerular function.
ANSWER
False
Rationale: Hydronephrosis is caused by a urinary
obstruction, so it is considered an obstructive
disorder. The glomerulus is not involved.
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
URINARY TRACT INFECTIONS


Bacteria usually enter through the urethra
Host defenses include:
 Washout phenomenon
 Protective mucus
 Local immune responses and IgA
 Normal bacterial flora
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 (Normal 8-20 mg/dL)
 PCR is 4.7 mg/dL (Normal 0.6-1.2 mg/dL)
Question:
 What complication are you most worried about?
Why?
QUESTION
Tell whether the following statement is true or
false:
Urinary tract infections (UTIs) are usually caused
by a virus.
ANSWER
False
Rationale: UTIs are most often caused by
bacteria that enter through the urethra (most
common) or the bloodstream.
STRUCTURE OF THE GLOMERULUS



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
Urine
Epithelial
cell
Foot processes
Basement membrane
Blood in
capillary
IMMUNE DAMAGE TO THE GLOMERULUS
Antibodies to glomerular
proteins
Circulating immune complexes
lodge in glomerulus
GLOMERULAR DAMAGE




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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
DISORDERS OF GLOMERULAR FUNCTION

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Nephritic syndromes Glomerular Problems
 Proliferative inflammatory response
Nephrotic syndrome Tubular Problems
 Increased permeability of glomerulus
Mixed nephritic and nephrotic responses
Chronic glomerulonephritis
Glomerular lesions associated with systemic
disease
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
 Azotemia
oliguria
changes decrease the GFR
(presence of nitrogenous wastes in the blood),
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
QUESTION
Tell whether the following statement is true or
false:
Nephritic syndromes are characterized by blood
in the urine.
ANSWER
True
Nephritic syndromes decrease the permeability of
the glomerular capillary membrane, which
results in hematuria, HTN, oliguria, and ↓ GFR.
SCENARIO:
A woman has diabetes mellitus
She has severe edema and frothy, colacolored 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 lupusrelated arthritis
Question:
 What are three reasons for her renal
problems?

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?
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?
TUBULOINTERSTITIAL DISORDERS



Acute tubular necrosis
Pyelonephritis
 Acute pyelonephritis
 Acute hypersensitivity to drugs
 Chronic pyelonephritis
Drug-related nephropathies
MALIGNANT TUMORS OF THE KIDNEY
MIKE’S KIDNEYS