1. Alterations of Renal and Urinary Tract Function
Chapter 30
Alterations of Renal and Urinary Tract Function
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2. Urinary Tract Obstruction
Urinary tract obstruction is an interference with the flow of urine at any site along the urinary tract
The obstruction can be caused by an anatomic or functional defect
Obstructive uropathy
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3. Urinary Tract Obstruction (Cont.)
Severity based on:
Location
Completeness
Involvement of ureters and/or kidneys
Duration
Cause
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4. Upper Urinary Tract Obstruction
Hydroureter
Accumulation of urine in the ureter
Hydronephrosis
Enlargement of the renal pelvis and calyces
Ureterohydronephrosis
Dilation of both the ureter and the pelvicaliceal system
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5. Urinary Tract Obstruction
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6. Upper Urinary Tract Obstruction
Compensatory hypertrophy and hyperfunction
Obligatory growth
Compensatory growth
Postobstructive diuresis
Nephrogenic diabetes insipidus
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7. Upper Urinary Tract Obstruction (Cont.)
Kidney stones
Calculi or urinary stones
Masses of crystals, protein, or other substances that form within and may obstruct the urinary tract
Risk factors
Gender and age
Race
Geographic location
Seasonal factors
Fluid intake
Diet
Occupation
Kidney stones are classified according to the minerals that make up the stone
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8. Kidney Stone Formation
Supersaturation of one or more salts
Presence of a salt in a higher concentration than the volume able to dissolve the salt
Precipitation of a salt from liquid to solid state
Temperature and pH
Growth into a stone via crystallization or aggregation
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9. Kidney Stone Formation (Cont.)
Other factors affecting stone formation
Crystal growth-inhibiting substances
Particle retention
Matrix
Stones
Calcium oxalate or calcium phosphate
Struvite stones
Uric acid stones
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Kidney Stones
Manifestation
Renal colic
Evaluation
Imaging studies
24-hour urinalysis
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Kidney Stones (Cont.)
Treatment
High fluid intake
Decreasing dietary intake of stone-forming substances
Stone removal
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12. Lower Urinary Tract Obstruction
Neurogenic bladder
Dyssynergia
Detrusor hyperreflexiad---overactive
Detrusor areflexia---underactive
Overactive bladder syndrome (OBS)
Frequency, urgency, nocturia
Obstruction
Urethral stricture, prostate enlargement, pelvic organ prolapse
Partial obstruction of bladder outlet or urethra
Low bladder wall compliance
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Which of the following is a risk factor for postobstructive diuresis?
Dehydration
Hypertension
Unilateral obstruction
Neurogenic diabetes insipidus
Correct Answer: B
Postobstructive diuresis is the rapid elimination of fluid after an obstruction is removed. The risk factors include bilateral obstruction, nephrogenic diabetes insipidus, hypertension, edema, congestive heart failure, and uremic encephalopathy. Neurogenic diabetes insipidus is caused by insufficient amounts of antidiuretic hormone (ADH). Rapid postobstructive diuresis causes dehydration and fluid and electrolyte imbalances.
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Tumors
Renal tumors
Renal adenomas
Renal cell carcinoma (RCC)
Bladder tumors
Transitional cell carcinoma (most common)
Gross, painless hematuria
Most common in males older than 60 years and smokers
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15. Urinary Tract Infection (UTI)
UTI is inflammation of the urinary epithelium caused by bacteria
Acute cystitis
Painful bladder syndrome/interstitial cystitis
Acute and chronic pyelonephritis
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16. Urinary Tract Infection (UTI) (Cont.)
Most common pathogens
Escherichia coli
Virulence of uropathogens
Host defense mechanisms
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17. Urinary Tract Infection (UTI) (Cont.)
Acute cystitis
Cystitis is an inflammation of the bladder
Manifestations
Frequency
Dysuria
Urgency
Lower abdominal and/or suprapubic pain, low back pain
Treatment
Antimicrobial therapy
Increased fluid intake
Avoidance of bladder irritants
Urinary analgesics
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18. Urinary Tract Infection (UTI) (Cont.)
Painful bladder syndrome/Interstitial cystitis
Nonbacterial infectious cystitis; noninfectious
Manifestations
Most common in women 20 to 30 years old
Bladder fullness, frequency, small urine volume, chronic pelvic pain
Treatment
No single treatment effective, symptom relief
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19. Urinary Tract Infection (UTI) (Cont.)
Pyelonephritis
Acute pyelonephritis
Acute infection of the ureter, renal pelvis, interstitium
Vesicoureteral reflux, E. coli, Proteus, Pseudomonas
Chronic pyelonephritis
Persistent or recurring episodes of acute pyelonephritis that lead to scarring
Risk of chronic pyelonephritis increases in individuals with renal infections and some type of obstructive pathologic condition
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Glomerular Disorders
Glomerulonephritis
Inflammation of the glomerulus
Immunologic abnormalities (most common)
Drugs or toxins
Vascular disorders
Systemic diseases (secondary)
Viral causes
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Glomerulonephritis
Mechanisms of injury
Deposition of circulating soluble antigen-antibody complexes, often with complement fragments (type III hypersensitivity)
Antibodies reacting in situ against planted antigens within the glomerulus (type II hypersensitivity–cytotoxic)
Nonimmune (drugs, toxins, ischemia)
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22. Glomerulonephritis (Cont.)
Manifestations
Two major symptoms if severe
Hematuria with red blood cell casts
Proteinuria exceeding 3 to 5 g/day with albumin (macroalbuminuria) as the major protein
Oliguria
Hypertension
Edema
Nephrotic sediment
Nephritic sediment
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23. Glomerulonephritis (Cont.)
Types
Membranous nephropathy/glomerulonephritis
Rapidly progressing glomerulonephritis
Antiglomerular basement membrane disease (Goodpasture syndrome)
Chronic glomerulonephritis
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Nephrotic Syndrome
Excretion of 3.5 g or more of protein in the urine per day
The protein excretion is caused by glomerular injury
Findings
Hypoalbuminemia
Edema
Hyperlipidemia and lipiduria
Vitamin D deficiency
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25. Nephrotic Syndrome (Cont.)
Membranous glomerulonephritis
Focal segmental glomerulosclerosis
Minimal change nephropathy (lipoid nephrosis)
Nephritic syndrome
Hematuria with RBC casts
Mild proteinuria
Immune injury
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26. Acute Kidney Injury (AKI)
Renal insufficiency
Renal failure
End-stage renal failure (ESRF)
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27. Acute Kidney Injury (AKI) (Cont.)
Prerenal
Most common cause of ARF
Caused by impaired renal blood flow
GFR declines because of the decrease in filtration pressure
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28. Acute Kidney Injury (AKI) (Cont.)
Intrarenal
Acute tubular necrosis (ATN) is the most common cause of intrarenal renal failure
Postischemic or nephrotoxic
Oliguria
Postrenal
Occurs with urinary tract obstructions that affect the kidneys bilaterally
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29. Acute Kidney Injury (AKI) (Cont.)
Initiation phase
Kidney injury is evolving
Prevention of injury is possible
Maintenance (oliguric) phase
Established kidney injury and dysfunction
Urine output is lowest during this phase, and serum creatinine and blood urea nitrogen both increase
Recovery (polyuric) phase
Injury repaired and normal renal function reestablished
Diuresis common
Decline in serum creatinine and urea
Increase in creatinine clearance
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30. Chronic Kidney Disease (CKD)
Progressive loss of renal function that affects nearly all organ systems
Associated with HTN, diabetes, intrinsic kidney disease
Stages:
Normal (GFR >90 mL/min)
Mild (GFR mL/min)
Moderate (GFR mL/min)
Severe (GFR mL/min)
End stage (GFR less than 15)
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31. Chronic Kidney Disease (CKD) (Cont.)
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32. Chronic Kidney Disease (CKD) (Cont.)
Proteinuria and uremia
Due to glomerular hyperfiltration
Damages interstitial tissue of kidney via inflammation
Creatinine and urea clearance
GFR falls
Plasma creatinine increases
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33. Chronic Kidney Disease (CKD) (Cont.)
Fluid and electrolyte balance
Sodium and water balance
Sodium excretion increases with obligatory water excretion leading to sodium deficit and volume loss
Concentration and dilution ability diminishes
Potassium balance
Tubular secretion increases early
Once oliguria sets in, potassium retained
Acid-base balance
Metabolic acidosis when GFR 30%-40%
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34. Chronic Kidney Disease (CKD) (Cont.)
Fluid and electrolyte balance (Cont.)
Calcium, phosphate, bone
Reduced renal phosphate excretion, decreased renal synthesis of 1,25-(OH)2 vitamin D3 and hypocalcemia
Fractures
Protein, carbohydrate, fat metabolism
Anemia
Lethargy, dizziness, and low hematocrit are common
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35. Chronic Kidney Disease (CKD) (Cont.)
Alterations seen in following systems
Cardiovascular
Pulmonary
Hematologic
Immune
Neurologic
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36. Chronic Kidney Disease (CKD) (Cont.)
Alterations seen in following systems (Cont.)
Gastrointestinal
Endocrine and reproduction
Integumentary
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37. Signs and Symptoms of Kidney Failure
From Goldman L, Schafer AI: Goldman’s Cecil medicine, ed 24, Philadelphia, 2012, Saunders; redrawn from Forbes CD, Jackson WF: Color atlas and text of clinical medicine, ed 3, London, 2003, Mosby.
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A patient presents with flank pain and anuria followed by polyuria after undergoing catheterization of the ureters. What is the most likely cause of this condition?
Acute tubular necrosis
Prerenal acute renal failure
Postrenal acute renal failure
Intrarenal acute renal failure
Correct Answer: C
Postrenal acute renal failure occurs with urinary tract obstruction caused by diagnostic catheterization of the ureters. Prerenal acute renal failure is caused by impaired blood flow. Intrarenal acute renal failure results from acute tubular necrosis that is caused by ischemia, usually after surgery.
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Which of the following is a symptom of chronic renal failure?
Hypotension
Hypokalemia
Hypocalcemia
Hypernatremia
Correct Answer: C
Chronic renal failure produces hypocalcemia secondary to impaired renal synthesis of vitamin D. Hypertension occurs in chronic renal failure, not hypotension. In chronic renal failure sodium is lost in the urine, producing hyponatremia and potassium is retained, producing hyperkalemia.
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