1 chapter 18 renal failure. 2 section i. introduction
TRANSCRIPT
1
Chapter 18
Renal Failure
2
Section I .
Introduction
3
But also regulate a variety of material in plasma to maintain the homeostasis of internal environment (osmolality and acid-base balance)
Kidneys are the principal excretive organs
Not only excrete waste metabolic products
to remove various harmful substances,
Besides, kidneys also produce some bioactive substances
renin, prostaglandins (regulation of blood pressure) erythropoietin (formation of matured RBCs) active vitamin D (metabolism of calcium and phosphorus)
4
But also regulate a variety of material in plasma to maintain the homeostasis of internal environment (osmolality and acid-base balance)
Kidneys are the principal excretive organs
Not only excrete waste metabolic products
to remove various harmful substances,
Besides, kidneys also produce some bioactive substances
renin, prostaglandins (regulation of blood pressure) erythropoietin (formation of matured RBCs) active vitamin D (metabolism of calcium and phosphorus)
5
The following pathologic process is termed ''renal failure'':
Glomerular filteration rate↓ Retention of metabolic wastes, Disturbanc of internal environment
Uremia
Renal Failure Acute renal failure (ARF) (CRF) Cronic renal failure
a serial of clinical manifestations
Various causes
Severely impair renal function
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1. Causes of renal dysfunction
(1) Primary renal disease (2) Renal injury secondary to systemic diseases.
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1. Causes of renal dysfunction
(1) Primary renal disease (2) Renal injury secondary to systemic diseases.
1) Glomerular disease
2) Renal tubular disease
3) Interstitial nephritis 4) Others:
glomerulonephritis; nephrotic syndrome renal glucosuria; aminoaciduria, renal tubular acidosis
acute or chronic interstitial inflammationrenal injury, tumor, calculus; obstructive nephropathy; vascular nephropathy
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1. Causes of renal dysfunction
(1) Primary renal disease (2) Renal injury secondary to systemic diseases .
1) Circulatory system diseases:
2) Auto-immune and connective tissue diseases:
3) Metabolic diseases:
4) Hematological diseases:
5) Others:
Shock, AS, thrombosis, etc.
Lupus nephritis, renal injury by rheumatoid arthritis, etc
Nephropathy caused by amyloidosis, diabetic or hyperuricemia
Renal injury by plasmacyte disease, multiple myeloma or leukemia
Heart failure, hepatic disease, endocrine disease and malignant tumors
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The anatomic and functional unit of kidney is nephron, which consists of glomerulus and renal tubule. Each human kidney has approximately 1 million nephrons. The glomerular function is to form original urine by filtration, while the tubule perform reabsorption and secretion. The basic presentation of RF include:
2. The basic manifestation of RF
(l) Dysfunction of glomerule
(2) Dysfunction of renal tubules
(3) Dysfunction of renal endocrine
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Renal blood flow Effective filtration pressure of the glomerule Kf (LPA, permeability and total filtration area)
125ml/min180L/day
1.5L/day
99%
20% of CI
Abnormality of urinary quality
Alteration of urinary quantity
(l) Dysfunction of glomerule
Permeability (of glomerular filtration membrane)
GFR
(hematuria & proteinuria)
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(2) Dysfunction of renal tubules
The secretion and reabsorption function are very important for maintain the homeostasis of internal environment
l ) Principal influencing factors
① Renal tubular EC (may impaired by ischemia,
hypoxia, infection and toxins)
② Neuro-humoral factors (Aldosterone, ADH, ANP, PTH etc.)
③ Concentration and flow rate of the initial urine
(ANP: atrium natriuretic peptide; PTH: parathyroid hormone)
180L/d
99%
1.5L/d
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① Dysfunction of reabsorption
Proximal convoluted tubule: glucosuria, phosphuria,
aminoaciduria, Na+ and H2O retention, renal tubular acidosis
③ Acid-base Disturbances
Proximal tubule (secrete H+, NH4+, NH3 ; reabsorb HCO3
–);
Medullary loop (reabsorb b HCO3– and NH3)
Distal tubule (secrete H+)
② Dysfunction of concentration and dilution
Henle’s (medullary) loop and collecting tubule: polyuria, Isosthenuria (isotonic), Hyposthenuria (hypotonic)
2) Types of renal tubular dysfunction
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Renal Hypertension
(3) Dysfunction of renal endocrine
① Increased secretion of rennin Renin
③ Increased secretion of endothelin ET
② Declined Kallikrein-kinin system (KKS) Kinin
④ Inadequate synthesis of prostaglandins from arachidonic acid PGE2 , I2
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EPO
HCI
1,25-(OH)2- D3 PTH
Renal aneamia
Ulceration
Renal osteodystrophy
⑤ Decreased eryhropoietin
⑥ Decreased 1-hydroxylase ⑦Weakened inactivation to PTH
⑧Weakened inactivation to gastrin
(90% formed in kidney)
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Section 2.
Acute Renal Failure
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Oliguria or anuria Retention of nitrogenous wastes (azotemia)
water/electrolyte acid-base disturbance
Rapidly and severely decline of GFR Kidneys fail to excretion and regulation in hours to days
Various causes
Oliguria is usually emphasized in the past, but in some cases, patients have high level BUN (azotemia) while urine volume does not change. It is called non-oliguria ARF
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l. Causes and classification
Acute renal failure (ARF) may result from a wide variety of
diseases (shock, heart failure, severe infection, hepatic diseases),
trauma, surgical procedures, drugs, renal toxins and urinary
tract obstruction.
According to causes, ARF may be divided into three main
categories: Prerenal
Intrarenal acute renal failure
Postrenal
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caused by any disorder external to the kidneys that rapidly and severely decreases the blood supply to the nephron.
caused by disease of the renal tissue itself, affecting the blood vessels, glomeruli or tubules.
caused by obstructive disorders (uretal or urethral) that canblock or partially block urine flow, while the kidney's blood supply and other functions are initially normal.
( l ) Prerenal failure (functional RF or prerenal azotemia)
(2) Intrarenal failure (parenchymal RF)
(3) Postrenal failure (Obstructive RF, Postrenal azotemia)
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Sudden decrease of renal perfusion
Hypovolemia, Acute heart failure
Expanded vascular bed volume (Hepatorenal syndrome
Anaphylactic shock, etc. )
Renal vascular blockage or auto-regulation disturbances
( l ) Prerenal failure
Azotemia(urinary Cr/plasma Cr > 40 ) Oliguna (<400ml/day) Urinary Na+<20 mmol/L Urine gravity > 1.020 No RBC, WBC or cast in urine
GFR↓Na+, H2O reabsorption↑
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(2) Intrarenal failure
Causes: intrinsic (parenchymal) renal diseases
1. Renal tubular diseases
2. Glomerular diseases
3. Renal interstitial diseases
4. Renal blood vessel diseases
Acute Tubular Necrosis (most common)
Acute renal ischemia Acute renal poisoningRenal tubule blocked by Hb or Mb
Glomerulonephritis, pye1onephritis, etc
Severe infection, drug allergy, etc
Thrombosis, DIC, etc
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Clinical features:
1. Oliguria or Non-oliguria
2. Isothenuria
the specific gravity of urine become fixed at 1.010 or 0.285 mOsm / L (equal to the osmotic concentration of plasma), implying an inability of the kidney to concentration or dilute the urine.
3. Urinary Na+ >40mmo l/L (ability to reabsorb Na + )
4. Hematuria.
5. Azotemia(urinary Cr/plasma Cr < 20)
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increased intracapsular pressure →GFR↓↓
Renal pelvises hydropsy
increased renal interstitial pressure
suddenly anuria and azotemia
Stone or tumor →Bilateral Obstruction
(3) Postrenal failure
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There are three major factors may account for the development of ARF(ATN):
1. Renal hemodynamic factors
2. Nephronal factors
3. Filtration area and permeability
2. Pathogenesis
1. Alteration of renal hemodynamics
2. Renal tubule injury
3. Decreased ultrafiltration coefficient (Kf) of glomeruli
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2. Pathogenesis
1. Alteration of renal hemodynamics
2. Renal tubule injury
3. Decreased ultrafiltration coefficient (Kf) of glomeruli
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Oliguria or anuriaGFR
(l ) Alteration of renal hemodynamics
The decreased renal perfusion caused by renal vaso
constriction is the principal pathogenesis of ARF.
Effective filtration pressure, FF & Kf
There are many factors may associated with renal vasoconstriction:.
Renin-Angiotensin System
Catecholamine Prostaglandins, etc.
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Impairing proximal convoluted tube and ascending limb of medullary lope
stimulating juxtaglomerular cells in afferent arteriole
1) Renin-angiotension system
Toxin , Ischemia
Activating RAS
Renal perfusion pressure
Stimulating macula densa of juxtaglomerular apparatus
Reabsorption of Na+ vasoconstriction
(T-G feedback)
Na+ in distal convoluted tube
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2) Catecholamine (CA)
3) Prostaglandins (PG)
4) Endothelin (ET)
5) Others:
NO synthesis↓, ADH, PAF and TNF↑and ischemia- reperfusion injury → promote ATN
Renal diseases may stimulate blood vessel EC to secrete ET. During ARF the level of plasma ET and the ability of ET-R to combine ET are all increased, which will directly or indirectly lead to renal vasoconstriction
All these go into a vicious circle and cause increasingly severe damage
Decreased synthesis of PG → PGI2/TXA2↓
→ renal vasoconstriction
Effective circulating blood flow↓ or toxin → excitation of sympathetic-adrenomedullary system → CA↑→vasoconstriction of renal cortex especially of afferent arteriole
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(2) Renal tubule injury
Cast formation
1) Renal tubule obstruction
2) Renal tubule backflow of original urine
Loss of tubule integrity
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Renal tubule EC necrosis Basement membrane broken down
Oliguria
Oppressing Oppression renal tubule renal capillary
Interstitial edema formation
Backleak of original urine into renal interstitium
Loss of tubule integrity
Dead and detached ECs
Filtered protein (HB or MB)
Cast formation
Tubule obstruction
Intracapsular pressure
GFR
Renal tubule injury
Effective filtration p Aggravate Aggravate
tubule obstruction renal ischemia
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(3) Decreased ultrafiltration coefficient (Kf) of renal glomeruli
Decreased filter area↓
structural destruction of filter membrane
Ultrafiltration Coefficient↓
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3. Clinical course and manifestation
(l) Oliguria type of ARF
(2) Nonoliguria type of ARF
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When various diseases lead to destruction of the tubular cells of the nephron (as typically occurs in cases of ATN), a characteristic response pattern is noted.
It usually develops in three stages:
diuresis phase recovery phaseOliguria phase
(l) Oliguria type of ARF
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Oliguria:
Urine volume < 400 ml / day, or <50ml / day (anuria)
It usually occurs in one day after renal damage and lasting l-2 weeks. The longer the time last, the worse the prognosis is
A duration more than one month indicates that the necrosis of tubule is very severe.
l) Oliguria phase
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As the urine formation rapidly diminished, the wastes of protein metabolism and water, electrolytes accumulate in extracellular fluid, which is often characterized by:
4. Retention of water and sodium Edema, hyponatremia and even water intoxication would occur if there is water and salts overload
3. Metabolic acidosis
May depress CNS and heart, aggravate hyperkalemia
2. Hyperkalemia May lead to ventricular fibrillation and cardiac arrest (No.1 cause of death)
1. Azotemia Progressive elevation of NPN (Urea, creatinine, etc.)
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4. Edema, hyponatremia and Water intoxication
3. Metabolic acidosis
2. Hyperkalemia
Death Triangle
2. Hyperkalemia
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urine Na+ urine Na+ /serum Na+
urine Cr/plasma Cr; urine Cr/plasma Cr
Differences between functional and parenchymal ARF
RFI = FENa =
INDEXES F - ARF P - ARF Urine specific gravity > l .020 < l .0l 5 Urine osmolality > 500 mmol / L < 350 mmol / L Urine Na+ < 20 mmol / L > 40 mmol / L Urine Cr / Plasma Cr > 40 < 20 Renal failure index (RFI) < l > 2 FENa < l >2 Urinary sediment Normal Proteins, cells, casts
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2) Diuresis phase
If the patient pass through the oliguria phase safely, the tubular
EC may regenerate and the renal function would recover gradually.
An increasing urine volume is a signal of renal EC healing, and
suggests the start-up of diuresis phase if it is more than 400 ml per
day. After then, the urine volume increasing doubly up to 3-5L/da
y
and may last about one month.
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The mechanisms for diuresis including:
a) The RBF & GFR recovered gradually while the reabsorption function of regenerating immature tubules keep on abnormal.
b) The high level of metabolic products retained during the oliguria phase resulted in a hyperosmolarity diuretic effect.
c) The tubular integrity recovered, interstitial edema subsided, the casts to be washed out and the tubular obstruction relieved.
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During this stage, the excretion of urea and other nitrogenous
compounds lags behind that of salt and water as reflected by the
continual rise in the concentrations of these substances for
several days after the onset of the diuresis.
The reason is the incomplete recovery of GFR. Nevertheless,
the tubular function also not well recovered, the kidney still
work as a simple filter. Salt and water loss could occur and lead
to dehydration, hypokalemia and hyponatremia.
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Therefore, this stage is also considered to be a critical phase,
and it has been pointed out that approximately 25 percent of the
deaths in ARF occurred following the onset of the diuresis.
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The improvement of renal function leads to a gradual reduction of BUN and correction of water, electrolytes and acid-base imbalance. The full recovery is depends on the healing of tubular ECs.
This process may take up three months to one year. Unfortunately, not all individuals are restored to health and may become chronic renal failure due to serious damage of the renal tubular EC and the fibrosis of renal tissue.
3) Recovery phase
42
While oliguria is a hallmark of ARF, some patients will develop an acute lose of renal function without oliguria. The common cause of this type is renal toxic substances, especially the aminoglycoside antibiotics and radiography contrast agents.
(2) Nonoliguric type of ARF
It is suggested that in such cases, GFR has not been reduced
severely and might remain partial tubule function, but its ability of concentration is impaired. The urine volume may be more (about 400-1000ml / day) and the concentration of Na+ in urine may be lower, while azotemia is still existed.
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The prognosis of which is better than that of oliguria type. It might be related to either a milder renal injury or fewer complications because of better water/ electrolyte and acid-base balance. However, both types may transform each other, the nonoliguria type will become oliguria type if having not pay attention and treat properly.
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4. Principles of prevention and treatment
(l) Etiologic treatment (shock, infection, DIC, kidney disease,
recover renal perfusion, eliminate tubule obstruction, etc.)
(2) Diuresis (osmolar diuretic: improving perfusion,
excreting toxin and alleviating tubular obstruction)
(3) Maintaining water and electrolytes balance,
correcting hyperkalemia.
(4) Dialysis (peritoneal dialysis or hemodialysis)
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Rapidly and severely decline of GFR Kidneys fail to excretion and regulation in hours to days
Various causes
Oliguria or anuria Retention of nitrogenous wastes (azotemia)
water/electrolyte acid-base disturbance
Prerenal failure
(functional RF) Intrarenal failure (parenchymal RF)
Postrenal failure (Obstructive RF)
Acute Tubular Necrosis
Acute Renal Failure
Summary for ARF
Oliguria or anuria Retention of nitrogenous wastes (azotemia)
water/electrolyte acid-base disturbance
Acute Renal Failure
Acute Renal FailureIntrarenal failure (parenchymal RF)
Acute Tubular Necrosis
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renal tubule injury Renal hemodynamic alteration
Oliguria GFR
renal perfusion Tubule obstruction
Toxin , Ischemia
Summary for ARF
Pathogenesis
glomerular Kf
renal vasoconstrictionBackleak of original urine
into renal interstitium
effective filtration pressure
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Clinical course and manifestation
(l) Oliguria type of ARF
phase phase phase
hyperkalemia Metabolic acidosis water intoxication
Differences between functional and parenchymal ARF ( )
(2) Nonoliguric type of ARF
Summary for ARF
GFR has not been reduced severely and might remain partial tubule function, but its ability of concentration is impaired
Oliguria diuresis recovery
Urine specific gravity, osmolality, Na+, Cr , sediment
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(l) What are the primary causes of death in oliguria type of ARF?
Hyperkalemia; metabolic acidosis; water intoxication (2) How to differentiate the functional and parenchymal ARF
INDEXES F - ARF P - ARFUrine specific gravity Urine Na+
Urine Cr / Plasma CrUrinary sediment
Today’s question
Normal Proteins, cells, casts> 40 < 20
< 20 mmol / L > 40 mmol / L
> l .020 < l .0l5
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Section 3.
Chronic Renal failure
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CRF is characterized by progressive and irreversible lossof large numbers of functioning nephrons, which lead to a very significant reduction in GFR. The remnant nephron fail to excrete waste metabolic product and keep the constancy of internal environment.
Retention of waste metabolic productsWater/electrolyte and acid-base imbalance Disturbance of renal endocrine
progressive irreversible destruction of nephron
Various diseases (kidney or kidney-related diseases)
CRF
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A wide variety of renal disorders, including disorders of the blood vessels, glomeruli, tubules, renal interstitium and lower urinary tract, can cause CRF.
Common causes: Primary--Chronic glomerulonephritis, interstitial nephritis; Secondary--diabetic or hypertensive nephropathy (The incidence of secondary CRF is increasing recently, about 36% and
30% of CRF caused by diabetes and hypertension respectively in USA.)
CRF is the ultimate common outcome of various kidney or kidney-related diseases and have been called:
End-stage renal disease (ESRD).
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1. Process of disease
The general course of progressive renal failure may be divided into 4 stages
GFR BUN BCr Stages (ml/min) (mmol/L) (umol/L)
Compensatory Stage >50 <9 <178
Decompensatory Stage 25~50 9~20 178~445 (renal insufficiency)
Renal failure <25 20~28 451~707
Uremia <10 >28.6 >707
BCr = blood level of creatinine
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Decompensatory stage
Compensatory stage
Renal failure stage
Uremic stage
Clinical
manifestation
Asym
ptomatic
% of normal clearance rate of Cr
Clinical
Asymptomatic
CCr GFR BUN BCr (%) (ml/min) (mmol/L) (umol/L)
>30 >50 <9 <178
CompensatoryStage
(1)
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Decompensatory stage
Compensatory stage
Renal failure stage
Uremic stage
Clinical
manifestation
Asym
ptomatic
% of normal clearance rate of Cr
Clinical
Lassitude, Mild anemia, Nocturia, Alimental tract discomfort
CCr GFR BUN BCr (%) (ml/min) (mmol/L) (umol/L)
25~30 25~50 9~20 178~445
DecompensatoryStage
(2)
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Decompensatory stage
Compensatory stage
Renal failure stage
Uremic stage
Clinical
manifestation
Asym
ptomatic
% of normal clearance rate of Cr
Clinical
Anemia, Acidosis, Cl -↑ , Na+↓ Hypocalcemia, Hyperphosphatemia
CCr GFR BUN BCr (%) (ml/min) (mmol/L) (umol/L)
20~25 <25 20~28 451~707
Renal failure Stage
(3)
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Decompensatory stage
Compensatory stage
Renal failure stage
Uremic stage
Clinical
manifestation
Asym
ptomatic
% of normal clearance rate of Cr
Clinical
Various uremic symptoms
CCr GFR BUN BCr (%) (ml/min) (mmol/L) (umol/L)
<20 <10 >28.6 >707
Uremic Stage
(4)
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2. Pathogenesis
Despite primary causes, the pathogenesis of CRF is a process in which the nephrons to be damaged continually the renal function to be declined progressively until failed.
The degree of renal dysfunction depends on the number of intact nephron
The remnant nephrons (so called intact nephrons) are compensatory hypertrophy, but their number decreasing day by day and finally become decompensatory.
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Injuries → basement membrane permeability↑ Mesangial cells overload and damaged Proteinuria Mesangial cells proliferation and increased Cast formation production of extracellular matrix Tubule blocked Glomerulosclerosis
There are two principal types of nephron injury:
(1) Glomerulosclerosis
(2) Tubulointerstitial injury
1) Alteration of glomerular basement membrane permeability
2) Hemodynamic alterations of intact nephrone 2) Hemodynamic alterations of intact nephrone
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There are two principal types of nephron injury:
(1) Glomerulosclerosis
(2) Tubulointerstitial injury
The number of nephron decreasing day by day
→ glomerular hyperfiltration
→ further glomerular injury
→ pressure and flow in glomerular capillary of remnant nephron↑
1) Alteration of glomerular basement membrane permeability
2) Hemodynamic alterations of intact nephrone
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There are two principal types of nephron injury:
(1) Glomerulosclerosis
(2) Tubulointerstitial injury
Compensatory hypertrophy in remnant nephron
metabolism
oxygen consumption
free radical production Tubulointerstitial injury
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There are two principal types of nephron injury:
(1) Glomerulosclerosis
(2) Tubulointerstitial injury
Compensatory hypertrophy in remnant nephron
metabolism
oxygen consumption
free radical production Tubulointerstitial injury
Inflammatory response
fibrin deposition in tubules and
surrounding interstitium
62
There are two principal types of nephron injury:
(1) Glomerulosclerosis
(2) Tubulointerstitial injury
Loss of some nephrons leads to compensatory
hyperfunction of others, increasing their vulnerability
to damage and going to a vicious cycle—the nephrons
to be continuously lost and the GFR progressively
decreased until the renal function failed.
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3. Alteration of function and metabolism
(1) Disturbance of water, electrolyte and acid-base balance
(2) Azotemia
(3) Renal hypertension
(4) Hematologic disorders
1) Renal anemia; 2) Tendency of bleeding
(5) Renal Osteodystrophy
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(1) Disturbance of water, electrolyte and acid-base balance
l) Water disturbance Alteration of urine volume Changes in urine osmotic pressure
2) Electrolyte disturbance Natrium; Potassium; Calcium & Phosphorus
3) Metabolic acidosis
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a) Nocturia (urine volume night > daytime, or > 750 ml)
b) Polyuria (>2000 ml per day in adult)
Mechanisms: Increased blood flow and rapid flow rate of ①primary urine in the remnant nephrons; Hyperosmolarity d②iuretic effect; Decreased ability of urine concentration cau③sed by destruction of osmolar gradient in medulla.
c) Oliguria (< 400 ml per day in adult) when extremely few of f
unctional nephrons (GFR<5~10ml/min).
l) Water disturbance Alteration of urine volume Changes in urine osmotic pressure
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Hyposthenuria:
urine specific gravity < 1.020 (nomal 1.002 ~ 1.035)
Isosthenuria:
urine specific gravity fixed at 1.010 or 0.285 mOsm / L
(equal to the osmotic concentration of plasma, implying
inability of the kidney to concentration or dilute the urine)
l) Water disturbance Alteration of urine volume Changes in urine osmotic pressure
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2) Electrolyte disturbance
Natrium
Regulation ability↓, may maintain normal at compensatory stage but tend to depletion or retention at late stage.
Potassium
May maintain normal as long as the urine volume is not
decreased, although the regulation ability has been impaired.
Hyperkalemia may occur when oliguria, acidosis at late stage.
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Calcium & Phosphorus:
a) Hyperphosphatemia
GFR↓→excretion of P↓① → [P]↑→[Ca]↓→ PTH↑
Late stage (GFR<30ml/min): ② < ① → [P]↑+ → [P]↑↑③
Early stage (GFR>30ml/min): ≥ → [P] remain normal② ①
Inhibiting reabsorption of phosphorus by tubule②
phosphorus release from bone③
20
5
15
L
②
①100
10
40
70
30 30
N E
①
②
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b) Hypocalcemia
① Ingestion and absorption of Ca2+ inadequacy
② [P]↑→[Ca]↓to maintain [Ca][P] constant
↘ phosphorus excreting through intestine
→ interfering absorption of Ca2+
③ 1-hydroxylase↓→ 1,25-(OH)2-D3↓ ↘ intestinal absorption of Ca2+ ↓
↗ ④ Inactivation ↓ → PTH↑
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3) Metabolic acidosis
when GFR<20ml/min, metabolic acidosis will occur
① Decreased ability of tubule to excrete acidic products
(HPO42+, SO4
2+, etc.) AG↑, Cl - normal
② Decreased ability of tubule to
conserve HCO3- AG normal, Cl -↑
③ Decreased ability to secrete H+
interstitial nephritis
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(2) Azotemia
Non-protein nitrogen (NPN) > 28.6 mmol/L (40 mg/dl).
Urea, creatinine, uric acid
1) Blood urea nitrogen (BUN):
BUN is not a ideal index for renal function:
It is just increasing if the decrease of GFR more than 50%.
It may influenced by exogenous urea (protein intake) or endogenous urea (infection, alimentary tract bleeding)
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2) Creatinine (Cr):
Cr is end-product of creatine and phosphocreatine metabolism. Although Cr is rarely influenced by protein intake, it is also not sensitive during early stage of CRF.
However, the clearance rate of Cr (CCr ) is closely related to GFR, as it can be filtrated through glomerulus freely but can not be reabsorbed by tubule, and only small amount may be secreted by proximal tubule.
CCr = UV/ P (U = urinary level of Cr, V = urine volume per min, P= plasma level of Cr)
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(3) Renal hypertension
1) Sodium and H2O retention (sodium-dependent hypertension)2) Increased activity of renin-angiotensin system (renin-dependent hypertension)3) Decreased anti-hypertension agents secreted by kidney (Kallikrein-kinin system and PG system)
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1) Sodium and H2O retention (sodium-dependent hypertension)2) Increased activity of renin-angiotensin system (renin-dependent hypertension)3) Decreased anti-hypertension agents secreted by kidney (Kallikrein-kinin system and PG system)
Ability of excreting Na+, H2O↓→ Na+, H2O retention
→ blood volume↑→ cardiac output↑→ hypertension
↘more sensitive of blood wall → vasoconstriction ↗
(3) Renal hypertension
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(3) Renal hypertension
1) Sodium and H2O retention (sodium-dependent hypertension)2) Increased activity of renin-angiotensin system (renin-dependent hypertension)3) Decreased anti-hypertension agents secreted by kidney (Kallikrein-kinin system and PG system)
Disorder of renal circulation → hypoxia → activating RAA →AII↑→ vasoconstriction → peripheral resistance↑ ↘ ↘ Aldosterone ↑→ Na+, H2O retention → hypertension
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(3) Renal hypertension
1) Sodium and H2O retention (sodium-dependent hypertension)2) Increased activity of renin-angiotensin system (renin-dependent hypertension)3) Decreased anti-hypertension agents secreted by kidney (Kallikrein-kinin system and PG system)
Renal dysfunction Renal hypertension
(vicious circle)
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(4) Hematologic disorders
1) Renal anemia (97%) Decreased production of RBC ① Synthesis of erythropoietin↓; ② Deficiency of hematopoietic material (iron, folic acid) ③ RBC-inhibiting factors inhibit RBC production;
④ Aluminium toxication (inhibiting synthesis of hematin, interfering iron transfer and stem cells proliferation) Increased destroy or loss of RBC ⑤ Hemolysis, Hypersplenism ⑥ Bleeding
(Toxic substances: Guanidines, Amines, Phenols, PTH, Al, etc.)
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2) Tendency of bleeding (17-20%)
The main cause is the abnormality of platelet quality rather than its quantity.
Uremia CRF
Uremic toxins TXA2 ,PGI2 (guanidines, phenol) Vasopressin receptor
Platele dysfunction
Decreased adherence, aggregative function and release of PF3
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(5) Renal Osteodystrophy (renal osteopathy)
1) Disorder of Vitamin D metabolism
2) Disorder of Calcium and phosphorus metabolism and
secondly hyperparathyroidism
3) Aluminium accumulation
4) Acidosis
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Renal osteodystrophy
Chronic RF (dysfunction of excretion and endocrine of kidney)
Excretion of P↓
③Aluminium accumulation
↓absorption of Ca2+
②
Secondly hyperparathyroid
PTH↑
hypocalcemia
Hyperphosphatemia
④
Ca2+ in bone↓
bone lysis
Acidosis①
↓1,25-(OH)2-D3
Calcification of bone↓
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Section 4.
Uremia
82
Uremia
Retention of metabolic end-product and endogenous toxin Disturbance of water/electrolyte and acid-base balance
Disorder of endocrine function
End-Stage of ARF or CRF
a series of auto-toxic symptoms
83
1. Pathogenesis
(1) Uremic toxin: (more than 100)
(2) PTH
(3) Aluminium
84
(1) Uremic toxin: (more than 100) Urea; Guanidines; Amine and phenol ; Middle molecular weight toxins
1) Urea -principal end product of protein metabolism
May lead to headache, Anorexia, nausea, vomiting,
glucose tolerance↓ bleeding
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2) Guanidines –second abundant nitrogenous matter
The only confirmed pathway for guanidines synthesis is:
Both with strong toxicity May induce almost symptoms of uremia.
Methyl guanidine Guanidino succinic acid
(Normal pathway) (RF)
Guanidino acetic acid
Excretion
Arginine
Creatinine
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3) Amine and phenol
Produced by enteric germs, mainly toxic to nerve system
4) Middle molecular weight toxins (500-5000 Dalton)
Can removed by peritoneal dialysis but not hemodialysis May lead to peripheral or central nerve disorder, RBC and
platelet injury, cellular immune and endocrine dysfunction, etc.
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1) Mechanism:
① hypocalcemia stimulating thyroid proliferation secondly hyperparathyroidism PTH↑
② decreased elimination and degradation of PTH by kidney
(2) PTH
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2) Toxicity of PTH:
① Inducing renal osteodystrophy
② Neural toxicity (decreasing neural transmission)
③ Anemia and bleeding (inhibiting RBC production and Platelet aggregation)
④ Infection (inhibiting WBC migrating, phagocytosis and Ab production)
⑤Myocardium injury, vasodilation and B.P.↓
⑥ Soft tissue necrosis
⑦ Increasing protein catabolism nitrogenous substances↑
⑧ Increasing serum cholesterol and triglyceride
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2) Toxicity
Inhibiting enzymes, toxicity to cell nuclear
May induce dialytic encephalopathy,
osteomalacia and small-cell anemia.
(3) Aluminium
1) Mechanism:
95% of Al combined with transferrin in plasma, thus difficult to remove by dialysis
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2. Functional and metabolic alterations
System Altered function Manifestation
Nerve system Increase in metabolic Uremic encephalopathy products (urea, guanidine) Peripheral neuropathy
Cardiavascular Activation RAS Hypertension; system Excess ECF Congestive heart failure Elevated BUN Uremic pericarditis
Respiratory Acidosis Kussmaul’s respiration system Heart failure, Na+/H2O retention Pulmonary edema Hypoalbuminemia Urea stimulation Uremic pleuritis
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System Altered function Manifestation
Digestive Urea → ammonia Anorexia, nausea, system Vomiting, diarrhea gastrin →HCl↑ Ulceration
Endocrine Ability of hormone Disorder of endocrine system secretion or elimination↓ Sexual function impaired
Skin Ca2+, urea deposition Itch, urea cream
Immune Impaired cellular immunity Infection
Metabolism Glucose tolerance↓ Hypoproteinemia Hypertriglyceridemia
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(1) Preventing further renal injury
(2) Dialysis (hemodialysis or peritoneal dialysis)
(3) Renal transplantation
3. Principles of prevention and treatment
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1. A pathologic process of retention of waste metabolic products,
water/electrolyte and acid-base imbalance, disturbance of renal
endocrine caused by progressive irreversible destruction of
nephrons in kidney or kidney-related diseases is called chronic
renal failure. It usually go through 4 stages: compensatory stage,
decompensatory stage, renal failure stage and uremia stage.
Summary for CRF
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nephrons in kidney or kidney-related diseases is called chronic
renal failure. It usually go through 4 stages: compensatory stage,
decompensatory stage, renal failure stage and uremia stage.
2. The pathogenesis of CRF include 2 types of nephron injury:
glumerulosclerosis and tubulointerstitial injury.
The functional and metabolic alterations in CFR primarily incl
ude , ,
, hematologic disorders ( ,
), and .
Summary for CRF
water, electrolyte and acid-base imbalance azotemia
renal hypertension renal anemia
bleeding tendency renal osteodystrophy
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electrolyte and acid-base imbalance, azotemia, Renal hypertensio
n, hematologic disorders(Renal anemia, bleeding tendency), and r
enal osteodystrophy
3. A series of auto-toxic symptoms at end-stage of RF caused by
retention of metabolic waste and endogenous toxin, disturbance
of water/electrolyte and acid-base balance, disorder of endocrine
function are called uremia. The pathogenesis include uremic
toxins ( , , , .
), and . Besides the symptomes
of CRF, functional and metabolic alterations in most organ
systems may occur.
Summary for CRF
urea guanidines amine and phenol middle molecular
weight toxins PTH aluminium
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The End
Back to cover
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A. Definition of terms ( 15 %)
B. Fill in the blanks with suitable words (20%)
C. Answer questions (40%)
D. Case Presentation (25%)