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Alterations of Renal and Urinary Tract Function

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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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Urinary Tract Obstruction (cont’d)

Severity based on: Location Completeness Involvement of one or both upper urinary tracts Duration Cause

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Upper Urinary Tract Obstruction

Hydroureter Hydronephrosis

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Urinary Tract Obstruction

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Upper Urinary Tract Obstruction

Compensatory hypertrophy and hyperfunction Obligatory growth Compensatory growth

Postobstructive diuresis (nephrogenic diabetes insipidus)

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Upper Urinary Tract Obstruction (cont’d)

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• 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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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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Kidney Stone Formation (cont’d)

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 History Stone and urine analysis Intravenous pyelogram (IVP) or kidney, ureter,

bladder x-ray (KUB) Spiral abdominal CT

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Kidney Stones (cont’d)

Treatment: High fluid intake Decreasing dietary intake of stone-forming

substances Stone removal

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Lower Urinary Tract Obstruction

Neurogenic bladder Dyssynergia

• Detrusor hyperreflexia-overactive• Detrusor areflex-underactive

Overactive bladder syndrome (OBS)• Frequency, urgency, nocturia

Obstruction• Urethal stricture, prostate enlargement, pelvic organ

prolapse• Partial obstruction of bladder outlet or urethra

Low bladder wall compliance

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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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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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Urinary Tract Infection (UTI) (cont’d)

Most common pathogens Escherichia coli

Virulence of uropathogens Host defense mechanisms

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Urinary Tract Infection (UTI) (cont’d)

Acute cystitis Cystitis is an inflammation of the bladder Manifestations:

• Frequency• Dysuria• Urgency• Lower abdominal and/or suprapubic pain

Treatment:• Antimicrobial therapy• Increased fluid intake• Avoidance of bladder irritants• Urinary analgesics

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Urinary Tract Infection (UTI) (cont’d)

Interstitial cystitis Nonbacterial infectious cystitis 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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Urinary Tract Infection (UTI) (cont’d)

Pyelonephritis Acute pyelonephritis

• Acute infection of the 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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Chronic Pyelonephritis

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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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Glomerulonephritis (cont’d)

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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Glomerulonephritis (cont’d)

Types: Membranous nephropathy/glomerulonephritis Rapidly progressing glomerulonephritis

• Antiglomerular basement membrane disease (Goodpasture syndrome)

Chronic glomerulonephritis

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Glomerulonephritis (cont’d)

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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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Nephrotic Syndrome (cont’d)

Membranous glomerulonephritis Focal glomerulosclerosis Minimal change disease (lipoid nephrosis) Nephritic syndrome

Hematuria Mild proteinuria Immune injury

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Acute Kidney Injury (AKI)

Renal insufficiency Renal failure End stage renal failure (ESRF)

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Acute Kidney Injury (AKI) (cont’d)

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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Acute Kidney Injury (AKI) (cont’d)

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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Acute Kidney Injury (AKI) (cont’d)

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Acute Kidney Injury (AKI) (cont’d)

Initiation phase Kidney injury is evolving Prevention of injury is possible

Maintenance phase Established kidney injury and dysfunction Urine output is lowest during this phase and serum

creatinine and blood urea nitrogen both increase Recovery phase

Injury repaired and normal renal function reestablished Diuresis common Decline in serum creatinine and urea Increase in creatinine clearance

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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 >90mL/min) Mild (GFR 60-89mL/min) Moderate (GFR 30-59mL/min) Severe (GFR 15-29mL/min) End stage (GFR less than 15)

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Chronic Kidney Disease (CKD) (cont’d)

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Chronic Kidney Disease (CKD) (cont’d)

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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Chronic Kidney Disease (CKD) (cont’d)

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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Chronic Kidney Disease (CKD) (cont’d)

Fluid and electrolyte balance 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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Chronic Kidney Disease (CKD) (cont’d)

Alterations seen in following systems: Cardiovascular Pulmonary Hematologic Immune Neurologic

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Chronic Kidney Disease (CKD) (cont’d)

Gastrointestinal Endocrine and reproduction Integumentary

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Signs and Symptoms of Kidney Failure