Disorders of Kidney and Urinary Tract Function

Urinary Tract

produces, stores, and eliminates urine

Composed of bladder, 2 kidneys, 2 ureters, and the urethra

Kidneys

Responsible for homeostasis via urine production and elimination

Body functions impacted

• BP

• Electrolyte and acid-base balance

• RBC production (makes EPO erythopoeitn that tells Bone marrow to make RBC)

• Bone health (convert vit. D into active form and Ca reabsorption)

in retroperitoneal space

papillae→ minor calyces → major malyc → renal pelvis → ureter → bladder

Flow of urine

Afferent arteriole

small blood vessels in the kidneys that deliver blood directly into the glomerulus for filtration

They are larger in diameter

feed blood into the glomerulus, creating the high pressure needed to filter waste, water, and solutes

By constricting (narrowing) or dilating (widening), they control how much blood enters the capillary bed

Specialized cells in their walls monitor blood pressure and release renin to help regulate systemic blood pressure

Renal artery

Carries oxygen-rich blood from the heart (via the abdominal aorta) into the kidneys

deliver blood for filtration

Renal Vein

Carries filtered, deoxygenated blood away from the kidneys back toward the heart (via the inferior vena cava

Efferent arteriole

a small blood vessel that carries filtered blood away from the glomerulus in the kidney

It transports blood out and away from the glomerular capillaries after filtration has occurred

has a smaller diameter (lumen) which creates resistance and helps maintain high hydrostatic pressure inside the glomerulus for proper filtration.

By constricting or dilating, the efferent arteriole helps regulate the glomerular filtration rate (GFR) despite normal shifts in systemic blood pressure

After leaving the glomerulus, it splits again into a second capillary network—the peritubular capillaries or vasa recta—to supply blood to the renal tubules and aid in reabsorption before returning to general circulation

Acute Kidney Injury AKI

Rapid decrease in kidney function

Chronic kidney disease CKD

loss of kidney function over time, results from failure of the body to remove waste products

Either kidney damage or GFR <60 ml/min/1.73 m2 for 3mths or more

incidence continues to rise in US and world

25% starting dialysis die within the 1st year of treatment

Etiology

• Diabetic nephropahty is MOST FREQUENT CAUSE OF CKD IN ESRD

• hypertensive nephrosclerosis

Complication

• Cardiovascular disease CVD

• metabolic acidosis

• chronic kidney disease- mineral and bone disorder CKD-MBD

• ANemia

• hyperkalemia

• hypervolemia

• uremia

Dignosis

• blood and urine tests

• additional lab tests

  • liver profile

  • thyroid function tests

  • electrolyte panel

  • imaging

    • KUB (kidneys, ureters, and bladder) x ray

    • renal ultrasound, arteriogram, CT, MRI

Treatments

• anti-hypertensives

  • ACE/ARB meds

• Lipid lowering agents

  • Statin therapy

• Hemodialysis

  • removal of toxins and excess fluid from the blood

• Peritoneal dialysis

  • removal of toxins and excess fluid by utilizing the peritoneum

• Renal transplantation

  • encouraged in those who have the potential of a good quality of life after transplantation

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End stage renal disease ESRD

occurs if CKD is not treated

results from failure of body to remove waste products

urine, acidosis, alkalosis

Urinary tract function

Elimination of waste products: without blood flow to kidneys, ____ output decreases

Acid-Base balance

• bicarbonate acts as buffer to maintain acid base balance

• In ___, kidneys reabsorb bicarbonate

• In ___, kidneys excrete more bicarbonate

muscle detrusor, transitional

Urinary bladder composed of ____ and ___ epithelium

UTI

infection of lower urinary tract of bladder, upper urinary tract, or the kidney

Cystitis

Infection of the bladder

most common bacterial infection

Risk factors

• diabetes mellitus

• familial predisposition

• obstruction

• neurogenic bladder

• use of spermicides and diaphragms

Pyelonephritis

infection of the renal pelvis (pyelum) and parenchyma (essential functional tissue) of the kidney

Risk factors

• female

• sexually active

• use of spermicides or diaphragm

• pregnancy

• genitourinary tract abnormalities

• neurogenic bladder (loss of bladder control caused by nerve damage that disrupts signals between the brain and the urinary system)

• immunosuppression

• diabetes

Ascedning bacterial colonization from urethra to bladder

• most caused by E coli

• classifified as complicated or uncomplicated

• Other causes

  • obstruction in flow of urine

  • stones

  • papillary necrosis

• residual urine retention

• bacteremia (____)

• instrumentation

• back flow of urine

  • vesicoureteral reflux (VUR) (a condition where urine flows backward from the bladder up into the ureters and toward the kidneys)

Glomerulonephritis (GN)

inflammation of the glomeruli and capillaries

characterized by mild proteinuria, hematuria, and edema

Etiology and pathogenesis

• postinfectious

• systemic disease

• toxin exposure

• thrombosis

• genetic

Nephrotic syndrome

defined by heavy protein loss in the urine (>3.5 g/day) resulting in low blood blood protein and severe fluid retention/edema

Ex: post streptococcal glomerulonephrisits (immune complex)

Clinical Manifesations

• hyperlipidemia

• PROTEINURIA

• hypoalbuminemia

• edema

• urinary fatty casts

Nephritic Syndrome

Involves inflammation of the kidney’s filters (glomeruli) which leads to blood in the urine (hematuria), high BP, and decreased kidney function

Clinical Manifestations

• HEMATURIA

• mild proteinuria

• RBC casts/dysmorphic RBCs

Diabetic Nephropahty

CKD resulting from hyperglycemia

• leading cause of end stage renal disease ESRD

• proteinuria and hyperfiltration

Risk factors

• poor glycemic control

• uncontrolled hypertension

• obesity

• smoking

• genetics

• Race (More prevalant in African American, hispanci, american indian, and asian people)

Progression of disease

hyperglycemia—> polyuria —> increased renal blood flow —> glomerular hypertrophy —> glomerular hypertension —> hyperfiltration

Clinical Manifestations

• Albuminuria

• hyperfiltration

• hypertension

Dignosis

• renal biopsy may not be necessary

• diabetes, HTN, and albuinuria leads to dignosis

Treatment

• maintain BP <140/90

  • ACE inhibitors

  • ARBs

• Blood cholestrol control

  • statins (prescription medications used to lower LDL (“bad”) cholesterol and reduce the risk of heart attacks and strokes)

• Maintain A1C <7%

  • lifestyle modifications

  • Glucose lowering meds

MOST FREQUENT CAUSE OF CKD IN ESRD

moderate albuminuria= early indicator

Basement membrane thickening, mesangial expansion, increased glomerular permeability, decreased GFR

Renal Calculi Nephrolithiasis KIDNEY STONE

Results from formation or urinary crystals into larger stones

• common obstruction (usually affecting white males)

Risk factors

• previous stones

• dehydration

• hypercalcuria

• hyperoxaluria (oxalate- nuts, spinach)

• high sodium diet

Compostion of Calculi

• majority are calcium based

• less common: uric acid, struvite (magnesium ammonium phosphate), cysteine stones (amino acid cystine)

Stone Formation

• damage to lining of urinary tract

• crystal aggregation

• slow urine flow to allow crystallization

• excretion of large amounts of calcium

Clinical Manifestations

• acute, unilateral flank pain

• nausea

• vomiting

• sever pain that comes and goes (renal colic)

Diagnosis based on clinical symptoms, ultrasound, xray

GFR glomerular filtration rate

blood test that measures the level of waste products, primarily creatinine or cystatin C

measures how well your kidneys filter waste from your blood (higher number is better)

Polycystic Kidney Disease PKD

genetic disorder causing numerous fluid filled cysts to grow in kidneys, manifestation 30-50yrs

Cysts enlarge the kidneys and progressively reduce their function, often leading to kidney failure and high BP

Hypertensive Nephrosclerosis

chronic kidney damage caused by long-term high blood pressure that hardens, thickens, and narrows the small blood vessels inside the kidneys. This process reduces blood flow and oxygen to the kidney tissue, which can gradually lead to a loss of kidney function

increased pressure in glomerulus —> damage of glomerular cells —> glomerulosclerosis

Damage of small vessels in kidney —> inadequate blood supply —> dec BP to glomeruli —> glomerulosclerosis

Hyperfiltration —> thickening of glomerular vessels

Cardiovascular Disease CVD

Most common cause of death in CKD

HTN, dyslipidemia, and chronic inflammatory state

a group of conditions that affect the heart and blood vessels

Metabolic acidosis

In CKD, kidneys retain H+ ions

decreased kidney function leads to increased ammonia and retained H+ ions

Decreased kidney function decreases reabsorption of sodium bicarbonate NaHCO₃

Chronic kidney disease mineral and bone disorder CKD-MBD

systemic condition where failing kidneys disrupt the balance of minerals and hormones like calcium, phosphorus, parathyroid hormone (PTH), and vitamin D

bone disease in CKD resulting from mineral and hormonal changes

causes bone pain, deformities, and fractures

Results from abnormal bone turnover, hypocalcaemia, hyperphosphatemia, and hyperparathyoidism

• Phosphorus buildup: Damaged kidneys fail to remove extra phosphorus, causing high blood levels (hyperphosphatemia).

• Vitamin D failure: Kidneys stop converting vitamin D into its active form, which lowers calcium absorption from food.

• High PTH (Secondary Hyperparathyroidism): Low calcium and high phosphorus trigger parathyroid glands to release excess PTH, pulling calcium out of the bones

Anemia

decreased erythropoietin EPO

worsens with worsening CKD

Leads to increased cardiac preload, decreased afterload, and increased cardiac output

Hyperkalemia

Develops as oliguria develops

results from decreased aldosterone secretion and decreased excretion of potassium

Damaged kidneys cannot effectively filter out extra potassium

Excess potassium stops the heart from resetting its electrical charge properly. This can lead to severe arrhythmias (irregular heartbeats) and, in extreme cases, cardiac arrest

Hypervolemia

once GFR fails, renal secretion of Na and H2O decreases

Exacerbates CVD and LVH (left vent. Hyp. thickening of the wall of the heart's main pumping chamber, called the left ventricle)

medical condition where your body holds too much fluid and sodium in the blood, also known as fluid overload

Uremia

Results from waste product acculmulation

serious, life-threatening medical condition that occurs when damaged or failing kidneys can no longer filter waste products properly, causing toxins like urea and creatinine to build up in the blood

Stages of CKD

Name this

Glomerulonephrosis

damage in the glomeruli

characterized by protein uria (hypoproteinemia) and edema

Etiology and pahtogenesis

• diabetic nephropahty

• lupus

• minimal change diseases (kids)

• allergies