Pathophysiology Exam 3: Renal

What are the primary functions of the kidney?

Homeostasis Balance solutes and water Excrete metabolic wastes Conserve nutrients Regulate acid-base balance Helps to control pH (regulates bicarb)

Kidney structural abnormalities in children

Horseshoe kidney Hypospadias Epispadias Exstrophy of bladder

A nurse is assessing a client for early manifestations of chronic kidney disease (CKD). What would the nurse expect the client to display?

Hypertension

Nephrotic syndrome findings

Hypoalbuminemia (Serum albumen decreases—< 3 g/dl) Edema Hyperlipidemia and lipiduria (Cholesterol, phospholipids, and cholesterol increase) Vitamin D deficiency

Chronic pyelonephritis

In interstitium 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 Can progress to kidney failure Diabetes and obstructive neuropathy puts you at risk

Chronic kidney disease CM

Increased creatinine then BUN Acidosis, hyperkalemia Hypertension Anemia Bleeding GI problems Hyperphosphatemia Decreased Vitamin D activation Impotence Terry nails

Upper urinary tract obstruction: Potential consequences of dilation of the renal tubules

Increased pressure inside the renal capsule, compartment syndrome compressing blood vessels inside the kidney, renal ischemia Stasis of urine - risk of infection and stones

Glomerulonephritis

Inflammation of the glomerulus due to: Immunologic abnormalities (most common) Drugs or toxins Vascular disorders Systemic diseases (secondary: diabetes, HTN, bacterial toxins, CHF, lupus, and HIV related kidney diseases) Viral causes

Chronic kidney disease: Calcium, phosphate, bone

Reduced renal phosphate excretion, decreased renal synthesis of 1,25-(OH)2 vitamin D3 and hypocalcemia Fractures

Renal tumors

Renal adenomas (benign, encapsulated) Renal cell carcinoma (most common) Risk: Higher rate in men, smokers, obese, and uncontrolled HTN Appear healthy, just find a mass CM: Hematuria, dull-aching flank pain, weight loss (only in 10% pt have all these symptoms) Neuroblastoma: Wilms Tumor (rare embryonic tumor, 5% childhood cancers presents age 2-3)

Kidney stone CM

Renal colic (boring or burning pain, mild discomfort to extreme pain, characteristic to placement and movement of stone) (ureter-pelvic junction is flank pain) (down ureter is downward and anterior pain)

The GFR is considered to be the best measure of renal function. What is used to estimate the GFR?

Serum creatinine

An 86-year-old female has been admitted to the hospital for the treatment of dehydration and hyponatremia after she decreased her fluid intake to minimize urinary incontinence. The client's admitting laboratory results are suggestive of prerenal failure. The nurse should be assessing this client for which of the following early signs of prerenal injury?

Sharp decrease in urine output

Chronic kidney disease: Sodium and water balance

Sodium excretion increases with obligatory water excretion leading to sodium deficit and volume loss Concentration and dilution ability diminishes

Kidney stone pathophysiology

Supersaturation of one or more salts Precipitation of a salt from liquid to solid state or aggregation into crystals A deficiency of substances that inhibit stone formation

A young woman presents with signs and symptoms of urinary tract infection (UTI). The nurse notes that this is the fifth UTI in as many months. What would this information lead the nurse to believe?

There is possible obstruction in the urinary tract.

Bladder tumors

Transitional cell carcinoma (most common) Gross, painless hematuria (blood in urine) Most common in males older than 60 years and smokers

Chronic kidney disease: Potassium balance

Tubular secretion increases early Once oliguria sets in, potassium retained

Mixed incontinence

stress and urge

Acute kidney injury

sudden decrease of GFR with decreased urine output and elevated nitrogenous waste

Direct visualization tests

using scope to evaluate bladder and ureters Cystoscopy Ureteroscopy

Pediatric Renal function

↓ ability to remove excess water and solutes ↓ concentrating ability Narrow margin for fluid and electrolyte balance increased risk of drug toxicity

Elderly renal function

↓ renal blood flow and GFR (Altered sodium and water balance) Number of nephrons ↓ due to renal vascular and perfusion changes Response to acid-base changes delayed increased risk for drug toxicity Alterations in thirst and water intake

Female normal creatinine

0.6-1.1 mg/dl

Male normal creatinine

0.6-1.2 mg/dl

How much blood do the kidneys process each day?

1700L

How much urine do the kidneys produce each day?

1L

Acute kidney injury mortality rate

25-80%

Normal urinalysis pH

4.6-8.0

Normal BUN

7.0-18.0

Normal GFR

90-120 ml/min

Acute pyelonephritis

Acute infection of the ureter, renal pelvis, interstitium Caused by vesicoureteral reflux (backflow), E. coli, Proteus, Pseudomonas Fever, chills, flank or groin pain and other symptoms of UTI Older adults may have low-grade fever and non-specific symptoms Use cultures, s/s, targeted antimicrobial therapy, imaging study if complicated

Normal urinalysis color

Amber-straw

Acute cystitis TX

Antimicrobial therapy Increased fluid intake Avoidance of bladder irritants (bubble baths) Urinary analgesics

Acute kidney injury: Prerenal

Blood supply decreased (Shock, dehydration, vasoconstriction (anything that decreases blood supply)) Due to dehydration

Kidney stone primary mineral salt composition

Calcium (i.e., oxalate or phosphate): 70-80% Struvite (Magnesium ammonium phosphate): 10-15% Uric acid: 7-9% Cystine, ammonia acid urate or drug related: <1%

Chronic kidney disease

Chronic if lasts more than 3 months Destruction ranges from months to years and it is often undetected Kidneys can compensate Progressive loss of renal function that affects nearly all organ systems Associated with HTN, diabetes, intrinsic kidney disease

Tests for renal function?

Clearance and glomerular filtration rate (24 hour urine) Blood tests Urodynamic tests Direct visualization tests

Chronic kidney disease TX

Conservative Medical Management Dietary Management (low protein) Medication Management Dialysis and Transplant

Acute cystitis

Cystitis is an inflammation of the bladder

Urodynamic tests

Cystometry (measures water pressure) Uroflowmetry (measures time it takes to empty full bladder of urine) Postvoid residual (residual urine in bladder after voiding) Electromyography (measures nerve impulses and muscle activity in urethral sphincter) Video urodynamics (using ultrasound to look at size and shape of bladder)

Severe glomerulonephritis symptoms

Hematuria with red blood cell casts Proteinuria exceeding 3-5 g/day with albumin (macroalbuminuria) as the major protein

Exstrophy of the bladder

Herniation of the bladder through the abdominal wall

Children and incontinence

Daytime incontinence Primary enuresis (nighttime bedwetting, has never been continent) Secondary enuresis (had been continent for at least 6 months, due to stress) Have to rule out things like diabetes or anything that impairs the kidneys

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, and infection with direct injury)

Dysynergia

Detrusor hyperreflexia→ overactive bladder (failure to relax and store urine) Detrusor areflexia→ underactive bladder (failure to contract and empty) Spinal cord injury, etc. are at risk for this

Neurogenic bladder

Dsynergia Overactive bladder syndrome (OBS) Obstruction

Chronic kidney disease: Proteinuria and uremia

Due to glomerular hyperfiltration Damages interstitial tissue of kidney via inflammation

Maintenance phase of acute kidney injury

Established kidney injury and dysfunction Urine output is lowest during this phase, and serum creatinine and blood urea nitrogen both increase

Nephrotic syndrome

Excretion of 3.5 g or more of protein in the urine per day The protein excretion is caused by glomerular injury Membranous glomerulonephritis Focal segmental glomerulosclerosis Minimal change nephropathy (not much changes in pathology of nephron) (lipoid nephrosis)

Acute cystitis CM

Frequency of urination Dysuria Urgency Lower abdominal and/or suprapubic pain, low back pain

Overactive bladder syndrome (OBS)

Frequency, urgency, nocturia

Horseshoe kidney

Fused kidneys causing a single U-shape

Creatinine is elevated with ___

GFR

Chronic kidney disease: Creatinine and urea clearance

GFR falls Plasma creatinine increases

Glomerular Damage

Glomerular capillaries and the Bowman 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 Proliferative: number of cells increase Membranous: glomerular basement membrane thickens Sclerotic: amount of extracellular matrix increases All can decrease the efficiency of filtration (causes creatinine to increase) Allow blood cells, lipids, or proteins to pass into the urine

What are the components of a nephron?

Glomerulus Proximal tubule Loop of Henle Distal tubule Collecting duct

Kidney stone TX

High fluid intake, decreased dietary intake of stone-forming substances, stone removal

Nephritic syndrome

Inflammatory process damages the capillary wall Hematuria with red cell casts, mild proteinuria, immune mediated, decreased GFR Acute post-infectious glomerulonephritis Proliferative inflammatory response Azotemia (presence of nitrogenous wastes in the blood), oliguria, cola-colored urine Rapidly progressive glomerulonephritis Goodpasture syndrome (anti-glomerular basement membrane disease)

Phases of acute kidney injury

Initiation phase Maintenance (oliguric) phase Recovery (polyuric) phase

Recovery phase of acute kidney injury

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

Clearance and glomerular filtration rate (24 hour urine)

Inulin (has to be given by IV infusion, glycosaccharide, not metabolized elsewhere) Cystatin C Creatinine (secreted at steady state by muscles, can be affected by exercise and dehydration and BUN levels)

Chronic kidney disease stages

I—Normal (GFR >90 mL/min) II—Mild (GFR 60-89 mL/min) III—Moderate (GFR 30-59 mL/min) IV—Severe (GFR 15-29 mL/min) V—End stage (GFR less than 15)

Normal urinalysis normally negative

Ketones Glucose Bacteria RBC WBC Crystals Fat Casts Leukocyte esterase Nitrites

Initiation phase of acute kidney injury

Kidney injury is evolving Prevention of injury is possible

Acute kidney injury: Intrarenal (intrinsic)

Kidney tubule function decreased (Ischemia, toxins, intra-tubular obstruction (tubule function decreases)) Due to antibiotics Acute Tubular Necrosis

When kidneys fail

Less waste is removed; more waste remains in blood Unable to regulate fluid, electrolyte, and pH balance

Kidney stones

Masses of crystals, protein, and other substances Classified by their primary mineral salt composition

Chronic kidney disease: Acid-base balance

Metabolic acidosis when GFR 30%-40%

Painful bladder syndrome/Interstitial cystitis CM

Most common in women 20 to 30 years old Bladder fullness, frequency, small urine volume, chronic pelvic pain

What is the functional unit of the kidney?

Nephron

Kidney failure findings

Nitrogenous compounds build up in the blood (look at trends for pt) BUN: Blood urea nitrogen (increase) Creatinine (increase)

Painful bladder syndrome/Interstitial cystitis TX

No single treatment effective, symptom relief

Painful bladder syndrome/Interstitial cystitis

Nonbacterial infectious cystitis; noninfectious

Upper urinary tract obstruction: Compensatory hypertrophy and hyperfunction

Obligatory growth Compensatory growth

Glomerulonephritis CM

Oliguria (<400 ml/ 24 hours, < 30 ml/hr) Hypertension Edema Nephritic syndrome (associated with NSAIDs, more serious when presenting as a complication, loss of protein, hematuria and RBC casts in urine, more common in children) Nephrotic syndrome Sudden or insidious onset Loss of nephrons before symptoms develop Acute can be silent, moderate or severe

Blood tests for renal function

Plasma creatinine concentration Blood urea nitrogen (BUN)

The nurse is reviewing the lab results of a patient with suspected nephrotic syndrome. The nurse anticipates that the results to include

Protein in the urine

Urinary tract infection (UTI)

UTI is inflammation of the urinary epithelium caused by bacteria Acute cystitis (painful bladder syndrome) Painful bladder syndrome/interstitial cystitis Acute and chronic pyelonephritis Most common pathogens (Escherichia coli) Virulence of uropathogens (Host defense mechanisms)

Hypospadias

Urethral meatus is located on the ventral side or undersurface of the penis Chordee: Penile bowing

Epispadias

Urethral opening is on the dorsal surface of the penis

Bladder obstruction

Urethral stricture, prostate enlargement, pelvic organ prolapse Partial obstruction of bladder outlet or urethra Low bladder wall compliance

Urge incontinence

Urge: most common in adults, sudden urge to go or involuntary loss of urine, caused from involuntary contraction of tresser muscle associated with neurogenic disorders

Acute kidney injury: Postrenal

Urine flow blocked (Stones, tumors, enlarged prostate (obstructions)) Due to enlarged prostate

Upper urinary tract obstruction: Postobstructive diuresis

Usually mild physiologic response to correct Nephrogenic diabetes insipidus

Kidney stone risk factors

age (common < 50), sex, gender, geographic, seasonal, fluid intake, and occupation

Normal urinalysis turbidity

clear

Stress incontinence

common in women; men with prostate surgery, sneeze or cough involuntary

Renal insufficiency

decline in renal function to about 25% of normal or GFR of 25-30ml/min, increased BUN and creatinine

Urinalysis ketones

diabetic ketoacidosis, causes kidney problems

Functional incontinence

if pt has Alzheimer's or pt is immobile

Urinalysis leukocyte esterase

infection

Urinalysis nitrates

infection

Overflow incontinence

involuntary loss with overextended bladder, urethral obstruction

Normal urinalysis blood

negative

Normal urinalysis protein

negative to trace

End-stage kidney disease (ESKD)

only 10% remaining kidney function

Kidney stone evaluation

physical exam, Imaging studies, 24 hour urine

Renal failure

sig loss of renal function