💊370: Renal Flashcards
What is Uremia?
Renal function declines to 10% of normal
Uremic toxins accumulate
What is Acute Kidney Injury (AKI)?
Abrupt loss of renal function
⬆️SCr ⬆️BUN >10-15% baseline
Can progress to CKD
What are life threatening complications of AKI?
- Hyperkalemia
- Pulmonary edema
- Heart failure
What are supportive management measures for AKI?
- Correct intravascular volume status with pRBCs, plasma expanders, or diuretics
- Treat precipitating condition
- Withdraw nephrotoxic drugs
What is the cause of Hyperkalemia?
Kidney unable to excrete K+
➡️ redistributed our of cells during metabolic acidosis
Drugs (ACEIs)
Can cause arrhythmia and cardiac arrest
What lab values indicate hyperkalemia?
Severe: >= 7.0 mmol/L
K+ = 6.0-6.9 with ECG changes
What are the interventions for hyperkalemia?
- Reduce risk of arrhythmias
➡️ IV Calcium - Shift K+ into cells
➡️ Insulin (+glucose)
➡️ Sodium bicarbonate
➡️ Inhaled salbutamol - Remove K+
➡️Cationic exchange resins
➡️ Dialysis
➡️ Diuresis
What are erythropoiesis stimulating agents (ESA) used for?
Anemia of CKD
Structurally identical to endogenous EPO
Release reticulocytes from bone marrow
What is a prototype of erythropoiesis stimulating agents (ESA)?
Epoetin alfa (Eprex)
What are side effects of erythropoiesis stimulating agents (ESA)?
- Hypertension
- Risk of CV events
- Pure red-cell aplasia (PRCA)
What are non-pharmacological therapies for Hyperphosphatemia?
- Dietary restrictions (no dairy, beans, beer, meats)
- Dialysis
- Subtotal or Total parathyroidectomy
What are examples of Phosphate binders?
- Calcium
2. Sevelamer (Renagel)
What are pharmacological treatments of Hypocalcemia and Hyperparathyroidism?
- Vitamin D ⬆️ Ca absorption and suppresses PTH synthesis
What are common nephrotoxic drugs?
- NSAIDs
- Aminoglycosides
- Vancomycin
- Sulfonamides
- Amphotericin B
- Cyclosporine
- Radio-contrast media
- Cisplatin
What are the 3 major functions of the nephron?
- Filtration
- Reabsorption
- Secretion
What is the function of the Glomerulus/Bowman’s Capsule?
Filtration
Allows passage of small molecules (H2O, NaCl, glucose, amino acids, urea)
Stops cells, platelets, and proteins
What is the major functions of the Proximal Tubule?
Reabsorbs:
- NaCl
- Glucose
- K+
- H2O/water
- Protein
- Urea
- Amino acids
- HCO3
- PO4
Secretes:
- H+
- Foreign substances
- Anions + cations
What is the major functions of the Loop of Henle?
Concentration of urine
Descending:
- Water reabsorption
- NaCl diffuses in
Ascending:
- Na+ reabsorption
- Water stays in
Urea secretion in thin segment
What are the major functions of the Distal Tubule?
Reabsorbs:
- NaCl
- Water (ADH required)
- HCO3
Secretes:
- K+
- Urea
- H+
- NH3+
- Some drugs
What are the functions of the Collecting Duct?
Reabsorbs:
1. Water (ADH required)
Absorbs/secretes:
- Na+
- K+
- H+
- NH3+
Urea secretes in medulla
What are signs associated with kidney disease or injury?
- Albuminuria
- Hematuria
- Reduced GFR
- Low blood protein
- Edema
What is the average urinary output in healthy patients?
180 L/day
GFR > 90mL/min
What are the forces that influence glomerular filtration rate (GFR)?
- Glomerular blood hydrostatic pressure
- Plasma colloid osmotic pressure
- Capsular hydrostatic pressure
What is the most common cause of AKI?
Dehydration (hypovolemia) leading to poor perdición to kidneys
What is Acute Tubular Necrosis (ATN)?
Damage to tubules from toxins or ischemia
What is Glomerulonephritis?
Inflammation of the glomeruli caused by immune response
What is the pathophysiology of Glomerulonephritis?
- Antigen-antibody complexes produced in response to infection become trapped in glomerulus
- Causes inflammatory damage, reducing capacity for selective permeability
- Allow larger molecules to enter filter ➡️ proteinuria + hematuria
What are signs of Glomerulonephritis?
- Hematuria
- Proteinuria
- Hypertension
- Edema (hypoalbuminemia ➡️ third spacing)
What is the pathophysiology of Pyelonephritis?
- Fibrosis and scar tissue formation of kidney pelvis and parenchyma after infection
- Interferes with tubular absorption and secretions
Recurrent infections increase scar tissue
What are signs and symptoms of Pyelonephritis?
- Fever
- Abdominal pain
- Dysuria
- Cloudy urine
- Polyuria or urgency
- Urinary odour
What is Nephrotic Syndrome?
Manifestation of kidney failure
Caused by group of diseases that damage kidneys filtering system
What are signs and symptoms of Nephrotic Syndrome?
- Proteinuria >3g protein/ day
- Edema
- Foamy urine
- Weight gain
- Hypoalbunemia
- Hematuria
What is Nephritic Syndrome?
Nephron inflammation
Acute onset
Azotemia
Nephrotoxicity that involves excess nitrogen compounds (urea, creatinine, etc)
⬆️ BUN + SCr
Crystallized urea deposits
Can occur in all types of AKI
What is the normal pH of urine?
4.8-8.0
Diabetes and starvation ⬇️pH
Infections ⬆️pH
What is the normal range of urinary Specific gravity?
1.025-1.032
⬆️dehydration, UTI, glucosuria, renal artery stenosis, decreased perfusion
⬇️ renal failure, pyelonephritis, Acute tubular necrosis, excess fluid
Casts in urinary microscopic analysis
Precipitate from cells lining the renal tubules
Crystals in urinary microscopic analysis
- Infection
- Inflammation
- Stones
Epithelial cells in urinary microscopic analysis
Degeneration, necrosis of tubule cells
What is the normal range for BUN?
3.6-7.1 mmol/L
10-20mg/dL
What is the normal range of serum creatinine?
Women: 45-90
Men: 60-110 micromol/L
What is the best estimation of functioning renal tissue?
GFR
Creatinine is primarily excreted by the GF after being constantly released by which tissue?
Muscle
What conditions result in prerenal injury?
- Renal Artery vasoconstriction
- Renal Artery thrombosis
- Hemorrhage
- Hypotension
What hormone is synthesized and secreted by the kidneys?
Erythropoietin to produce RBC in bone marrow
What are causes of infra-renal AKI?
- Acute Tubular Necrosis
2. Glomerular, tubular or interstitial damage
What are causes of postrenal AKI?
- Renal calculi
- Ureteral stricture
- Benign prostatic hyperplasia (BPH)
- Tumor
- Blood clots in ureters/urethra
What are causes of prerenal AKI?
- Hypovolemia
- Decreased cardiac output
- Thrombo-embolitic obstruction of renal vasculature
What are signs of Azotemia?
- ⬆️ BUN + SCr
- Uremic frost
Can occur in all types of AKI