L3 Kidney disease Patho

What are the vital functions of the kidneys?

• Maintain fluid + acid-base balance

• Regulating electrolyte concentration

• Detoxifying the blood and eliminating wastes (med processing)

• Regulating BP

• Aiding RBC production (erythropoiesis)

• Regulating vitamin D + calcium formation

What are the components of the renal system?

• Kidneys

• Ureters

• Bladder

• Urethra

What are the 3 primary sections of the renal system? What does each consist of?

• Cortex (outer layer)

  • Glomeruli

  • Proximal tubules

  • Renal corpuscles

• Medulla

  • Pyramids

  • Distal tubules

  • Collecting ducts

• Pelvis

  • Urine collection starts

  • Start of ureter

What is a nephron? Role?

• Functional unit of the kidney

  • Million

• Role:

  • Filters substances from blood

  • Reabsorb filtered nutrients + water

  • Secrete waste

What are the components of a nephron? What is the role of each?

• Glomerulus

  • First filtering stage

  • Enter under high pressure → Protein + blood + large molecules stay in vessels → Filtrate continues on → Creatinine pulled out here + Never goes back in

• Bowman’s capsule

  • Contains glomerulus

  • Holding reservoir for filtrate

• Proximal tubule

  • Site of reabsorption of glucose, amino acids, metabolites, electrolytes, and water back into blood

  • Regulates how much sugar/electrolytes

• Loop of Henle

  • Further reabsorption of water + electrolytes

  • Descending → High permeability to water, NOT electrolytes

  • Ascending → High permeability to electrolytes NOT water

• Distal tubule

  • Fine tuning how much water/electrolytes we need to keep/excrete

• Collecting tubule/duct

  • Last piece before leaving

How is urine removed?

• Urine first enters the ureters via renal pelvis

• Then propelled by ureters into bladder via peristalsis

• Bladder activates stretch receptors

• Signal stimulates contraction of detrusor muscle via parasympathetic cholinergic motor fibers

• Relaxation of internal and external urethral sphincters = micturition (peeing)

Urine characteristics: Color, Total volume, Hourly volume

• Yellow → Dark amber can = dehydration, renal/liver disease

• Clear → Cloudy may = infection

• Total volume = 750 - 2000 mL/day

• Kidneys create at least 30mL/hr

What hormones are involved in fluid balance? What are they produced by? What does it do?

• Antidiuretic hormone (ADH)

  • Produced by pituitary gland

  • Alters the collecting tubules permeability to water

• Aldosterone

  • Produced + released by adrenal cortex

  • Regulates water reabsorption by the distal tubules + Changes urine concentration by increasing sodium reabsorption + Helps control secretion of potassium by the distal tubules

What are some other key hormones of the kidneys? What do they do?

• Calcitriol

  • Assists with converting vitamin D to its active form

• Erythropoietin

  • Stimulates RBC production

• Renalase

  • Affects heart function and BP by metabolizing catecholamines

• Renin

  • Helps regulate BP through angiotensin conversion

What factors influence renal laboratory values?

• Age

• Gender

• Muscle mass

• Capillary wall permeability

• Vascular and filtration pressure

• Hydration status.

What does eGFR measure and what is a normal value?

• How much the glomerulus is filtering

• Normal is greater than 90.

What is creatinine and how does it relate to GFR?

• Creatinine is an indirect marker of GFR

• When filtration drops, creatinine rises.

What does BUN measure and how is it affected by filtration?

• BUN measures how well the kidneys remove waste

• When filtration drops, BUN rises and depends on water reabsorption capacity.

How do we perserve renal function?

• Control of BP + glucose levels

• Adequate hydration status

• Smoking cessation (causes vasoconstriction)

• Limit alcohol, caffeine

• Limit sodium intake

• Caution with nephrotoxic drugs

• Renally dose meds based on kidney function (with help from pharmacist!)

What is glomerulonephritis? Pathophysiology? Causes?

• Inflammation of the glomerulus

• Patho: Injury to glomerulus → Triggers inflammatory reaction at the glomerulus → Causes glomerular filtration membrane to be more permeable → Allows passage of larger particles such as protein / blood through

• Causes: Immune relates (SLE lupus), DM, HTN, Infections

Symptoms of glomerulonephritis?

Increased:

• Protein

• Hematuria

• Casts on urine analysis

Labs:

• Elevated Creatinine + BUN

• Low GFR + Protein in serum

Other:

• Oliguria (less than 30mL/hr) or Anuria

• HTN

• Swelling

• Renal failure

Treatment for glomerulonephritis?

• Treat cause if possible!

• Supportive care

  • Low salt / phosphorous diet

  • Limit nephrotoxic drugs

  • Maintain hydration

What is urolithiasis? Causes? Risk of?

• Calculi (kidney stones) form when substances that normally dissolve in the urine precipitate.

  • Commonly comprised of calcium oxalate / calcium phosphate

• Causes:

  • Urinary stasis

  • Dehydration

  • Infection

  • Elevated urinary levels of salt and minerals

    • pH changes + Metabolic factors

    • Diet (high animal protein intake, Na, low fluid)

• Risk of renal tubule obstruction

Risk factors of urolithiasis?

• Genetics

• UTI

• Cystic kidney disease

• DM

• Obesity

• Gout

• Hyperparathyroidism

• Gastric bypass

What does Urolithiasis look like (colic VS noncolic)?

Pain = severe + shooting ; Flank / Costovertebral angle (CVA)

• Colic

  • Distension of collecting system or ureter

  • Acute, Intermittent, Radiating, Excruciating

• Non Colic

  • Distention of renal calices or pelvis

  • Dull, Deep w/ varying intensity

How is Urolithiasis diagnosed?

• Subjective findings → Hx pain

• Xray, CT

• Urinalysis / Analysis of calculi composition

Treatment of urolithiasis: Pharmacologic VS Calculi removal

• Pharm:

  • Analgesics

  • Antimicrobials

  • Diuretics (prevent urinary stasis)

• Removal

  • Increased fluid intake → If small will pass through micturition

  • Reduction of calculi size

  • Surgical removal

  • Urethral stents

How to prevent urolithiasis?

• Diet with foods low in calcium oxalate

• Fluids

• Management of gout, hyperparathyroidism

What is acute kidney injury (AKI)? What is classification based on?

• Sudden decline in kidney function related to decreased blood flow, toxins, or sepsis

• Based on location

Progression of AKI?

• Initiating event → Prevention still possible

• Maintenance (oliguric) phase

• Recovery (polyuric) phase

  • 3-12 months

  • A lot of urine output to catch up from oliguric phase

Types of AKI?

• Prerenal

• Intrarenal

• Postrenal

Prerenal: Cause, Urine output, Urine osmolality, Urine sodium

• Most common!

• Caused by hypovolemia

• Low urine output

• High urine osmolality

• Low urine sodium

Intrarenal: Cause, Urine output, Urine osmolality, Urine sodium

• Typically caused by tubular necrosis

  • Can also be caused by toxins, Contrast media, heavy metals, myoglobin from crush injuries

• Low urine output

• Low urine osmolality

• High urine sodium

Postrenal: Cause, Urine output, Pain

• Rare!

• Caused by obstruction in urinary tract

• No urine output

• Hours of flank pain

RIFLE criteria for acute kidney dysfunction/failure

• Risk

  • Increased creatinine x 1.5 / GFR decreased by 25%

  • Urine output <0.5mL/kg/hr → 6hr

• Injury

  • Increased creatinine x 2 / GFR decreased by 50%

  • Urine output <0.5mL/kg/hr → 12hr

• Failure

  • Increased creatinine x 3 / GFR decreased by 75%

  • Urine output <0.5mL/kg/hr → 24hr / anuria x 12hr

• Loss

  • Persistent acute renal failure >4 weeks

  • Some sort of intervention done to keep pt. alive

• ESKD

  • End stage kidney disease

  • > 3 months

  • Less than 10% kidney function

Supportive treatment of AKI?

• Manage potassium / electrolyte levels

• Limit sodium / phosphorous intake

• Balance fluid intake

• Avoid / reduce nephrotoxic drugs

• Short term dialysis in severe cases

What is chronic kidney disease? What does it specifically damage? How does it try to cope? What does coping result in?

• Progressive, irreversible loss of renal function

• Specifically damage to nephrons

• Initially nephrons hypertrophy to keep up with demand

  • Urine will have elevated protein, RBC, WBC, but other values normal until reach end stages

  • Ultimately see decreased GFR and tubular function

    • Impaired electrolyte balance and fluid conversion

  • Can maintain normal function until 75% of nephrons destroyed

What does chronic renal injury look like?

• Renal → Dry mouth, Decreased urine, Irregular pulses, Fatigue

• Cardio → Arrhythmias

• Respiratory → Infection, crackles, pleuritic pain

• GI → Sore + Bleeding gums, Hiccups, Metallic taste, Ammonia smell to breathe

• Skin → Pallid, Yellowish bronze color, Dry, Brittle nails/hair, Flaky urea deposits

• Neuro → Altered consciousness, muscle cramps/twitching, Itchy legs + feet

• Hematologic → Eady bruise / bleed

• Musculoskeletal → Fractures, Abnormal gait

How is chronic kidney injury diagnosed?

• Blood studies

  • Decreased → pH, Bicarb, HCT, Hgb

  • Increased → BUN, Creatinine, Sodium, Potassium

• Urine specific gravity

  • Fixed at 1.010

• Urinalysis

• Xray

• Renal biopsy

• EEG

Stages of chronic kidney injury?

• 1

  • Usually no symptoms

  • GFR >90

  • HTN common

• 2 “Mild CKD”

  • Subtle symptoms

  • GFR 60-89

  • HTN more visible

  • Increasing creatinine + urea levels

• 3 “Moderate CKD)

  • GFR a 45-59

  • GFR b 30-40

  • Same as 2

• 4 “Severe CKD”

  • GFR 15-29

  • Erythropoietin deficiency anemia

  • Hyperphosphatemia

  • Increased triglycerides

  • Metabolic acidosis

  • Hyperkalemia

  • Salt/water retention

• 5 “End stage KD”

  • GFR <15

  • As above

  • Waste elimination severely impaired

  • Urea + Creatinine levels build up in blood

CKD prevention / treatment?

• Conservative

  • Low protein diet

  • Reduce sodium / potassium intake

  • Manage fluid balance

• Dialysis

• Transplant

A 35 year old who was severely burned is now demonstrating symptomology associated with acute tubular necrosis (ATN). Which form of renal failure is this patient experiencing?

A) Extrarenal

B) Intrarenal

C) Prerenal

D) Postrenal

B) Intrarenal

A patient is diagnosed with renal calculus that is causing a urinary obstruction. Which symptoms would be most likely experienced?

A) Flank pain

B) Pyuria

C) hematuria

D) Anuria

A) Flank pain

A 42-year-old male is involved in a motor vehicle accident that has resulted in prerenal failure. What is the most likely cause of this patient’s condition?

A) Kidney Stones

B) Obstruction of the proximal tube

C) Inadequate renal blood flow

D) Obstruction of the ureters

C) Inadequate renal blood flow

Which type of acute kidney disease are associated with each cause (prerenal, intrarenal, postrenal)

1) Nephrotoxic antibiotics

2) Massive hemorrhage

3) Renal ischemia during surgery

4) Bilateral renal calculi

5) Untreated enlarged prostate

1. Intra

2. Pre

3. Intra

4. Post

5. Post

What mechanism most directly contributes to neurological symptoms such as confusion and peripheral neuropathy in patients with chronic kidney disease?

a. Accumulation of uremic toxins due to decreased renal clearance

b. Excessive deposition of calcium in neural tissues

c. Increased production of neurotransmitters due to metabolic imbalance

d. Elevated circulating catecholamines from sympathetic overactivity

a. Accumulation of uremic toxins due to decreased renal clearance

In chronic kidney disease, which mechanism is primarily responsible for the development of peripheral edema?

a. Increased capillary permeability from systemic inflammation

b. Reduced renal excretion of sodium and water due to decreased glomerular filtration

c. Excessive protein loss from the kidney causing hypoalbuminemia

d. Elevated hydrostatic pressure from uncontrolled hypertension

b. Reduced renal excretion of sodium and water due to decreased glomerular filtration