Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

Chapter 16
Kidney Function and Damage
Jean-Pierre Braun
Department of Physiopathology and Experimental Toxicology
National School of Veterinary Medicine of Toulouse
Toulouse, France
Herve P. Lefebvre
Department of Physiopathology and Experimental Toxicology
National School of Veterinary Medicine of Toulouse
Toulouse, France
I. INTRODUCTION
II. KIDNEY MORPHOLOGY AND FUNCTION
A. General Structure of the Kidneys
B. Glomerulus and Filtration
C. Tubule: Reabsorption and Secretion
III. TESTS OF KIDNEY FUNCTION
A. Indirect Tests of Glomerular Function
B. Direct Tests of Glomerular Function
C. Tests of Tubule Function
IV. TESTS OF KIDNEY DAMAGE
A. Glomerular Damage
B. Tubule Damage
V. BIOCHEMICAL CHANGES IN KIDNEY DISEASE
A. Chronic Renal Failure
B. Acute Renal Failure
C. Nephrotic Syndrome
D. Fanconi-Like Syndromes
REFERENCES
I. INTRODUCTION
Clinical biochemistry in nephrology is mainly used to diagnose
and monitor renal dysfunction or damage. This is of
special importance in human medicine, because of the frequent
observation of renal failure in elderly people, and in
canine and feline medicine, especially for the early detection
of chronic renal failure (CRF), which is frequent. In U.S.
private practice, however, renal disease was not reported
as one of the 29 most common disorders in dogs and was
ranked 17th in cats ( Lund et al. , 1999 ), and in a survey of
Australian practices, the expected frequency of renal failure
ranged from one case per week to one case every 2 weeks
(Watson et al. , 2001 ). A British survey indicated that 0.2%
of dogs were presented with suspected renal disease, which
was confirmed in 25% of the cases with no evidence of
breed or sex predisposition ( MacDougall et al. , 1986 ). The
reported prevalence of CRF in a U.S. university hospital
was three times higher in cats than in dogs ( Polzin et al. ,
1992 ). However, the frequency of renal disease increases
with age, especially in dogs and cats, as in humans ( Cowgill
and Spangler, 1981 ; Gobar et al. , 1998 ; McCall Kaufman,
1984 ). In U.S. veterinary university hospitals, renal disease
was observed in 15% of dogs more than 10 years old, in
33% of cats more than 15 years old ( Polzin et al. , 1989 ), in
3% of cats aged 7 to 10 years, and in 30% of cats more than
15 years old ( Krawiec and Gelberg, 1989 ).
Kidney diseases are uncommon in equids and cattle
( Fetcher, 1985 ). The latter show better resistance to a loss
of kidney function than monogastric animals because of
the filtration function of the rumen epithelium as shown by
bilateral nephrectomy ( Fetcher, 1986 ).
II . KIDNEY MORPHOLOGY AND FUNCTION
A . General Structure of the Kidneys
The mammalian kidney consists of tens of thousands to
millions of nephrons that function as parallel units. The
larger the species, the greater the number of nephrons per
kidney ( Kunkel, 1930 ; Rytand, 1937–1938; Vimtrup, 1928 ).
This ranges from about 10,000 in mice ( Cullen-McEwen
et al. , 2003 ), 175,000 in cats ( Brown et al. , 1993 ), 300 to
700,000 in dogs ( Finco and Duncan, 1972 ), and 7 million
in elephants, as compared to about 1 million in humans.
The number of nephrons progressively increases during
fetal development and is complete at birth (e.g., in sheep
or humans) or during the few days following birth (e.g., in
rat) ( Gimonet et al. , 1998 ). The number of nephrons in the
dog decreases slightly (5%) during the 2 first months of life,
whereas the glomerular volume increases by 33% ( Horster
et al. , 1971 ). However, great interindividual variability is
observed within species. In dogs, the size or the weight has
little influence on the number of glomeruli, but the size of
these latter is larger in larger breeds ( Finco and Duncan,
1972 ; Kunkel, 1930 ). In sheep, the number of nephrons in
twins was about 30% lower than in single lambs ( Mitchell
et al. , 2004 ) or showed no difference ( Bains et al. , 1996 ).
Clinical Biochemistry of Domestic Animals, 6th Edition 485
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