What cells release erythropoietin?
Interstitial cells in the peritubular capillary bed
What cells activate 25-OH-vitamin D?
Proximal tubule cells
What enzyme is used to convert 25-OH-vitamin D to active form?
1-alpha-hydroxylase
What cells release renin?
JG cells (afferent arteriole)
What is the action of prostaglandins in the glomerulus?
vasodilate afferent arteriole to increase RBF
What is the action of ang II at the glomerulus?
vasoconstrict efferent arteriole to increase GFR and FF (and to reabsorb Na from the proximal and distal nephron)
What is the role of ANP at the glomerulus?
Increase GFR and increase Na filtration with NO compensatory Na reabsorption (volume loss and Na loss)
What is the overall effect of aldosterone on the glomerulus?
Increases Na reabsorption
Increases K secretion
Increases H secretion
What things lead to K+ shift OUT of cells?
Digitalis hyperOsmolarity Lysis of cells Acidosis Beta-blockers Insulin deficiency
(DO LAB for insulin deficiency)
What things cause K+ shift IN to cells?
hypoosmolarity
Insulin (increase Na/K ATPase)
Alkalosis
Beta-agonists (increase Na/K ATPase)
Electrolyte deficiency: nausea, malaise, stupor, coma
Na
Electrolyte deficiency: tetany, torsades de pointes
Mg
Electrolyte deficiency: bone loss, osteomalacia
PO4
Electrolyte deficiency: U waves on ECG, flattened T waves, arrhythmias, muscle weakness
K
Electrolyte deficiency: Tetany, seizures, QT prolongation
Ca
Electrolyte surplus: low DTRs, lethargy, bradycardia, hypotension, cardiac arrest, hypocalcemia
Mg
Electrolyte surplus: Renal stones, metastatic calcifications, hypocalcemia
PO4
Electrolyte surplus: irritability, stupor, coma
Na
Electrolyte surplus: kidney stones, bone pains, abdominal pain, anxiety, alteredmential status
Ca
Electrolyte surplus: Wide QRS, peaked T waves on ECG, arrhythmias, muscle weakness
K
Causes of Respiratory Acidosis (Pco2 > 40)
Hypoventilation (airway obstruction, acute lung disease, chronic lung disease, opioids, weak respiratory muscles)
Causes of metabolic acidosis (high anion gap > 8-12)
MUDPILES: Methanol Uremia DKA Propylene glycol Iron tablets; INH Lactic acidosis Ethylene glycol (oxalic acid) Salicylates (late)
Cuases of non-anion gap metabolic acidosis (8-12)
HARD-ASS Hyperalimentation Addison disease Renal tubular acidosis Diarrhea Acetazolamide Spironolactone Saline infusion
Causes of Respiratory Alkalosis (Pco2 < 40)
Hyperventilation (hysteria, hypoxemia, salicylates (early), tumor, pulmonary embolism)
Causes of metabolic alkalosis
Loop diuretics
Vomiting
Antacid use
Hyperaldosteronism
Type of renal tubular acidosis with:
- pH>5.5
- Hypokalemia
- High urine pH
Type 1
Type of renal tubular acidosis with:
- pH <5.5
- Hyperkalemia
- High urine pH
Type 4
Type of renal tubular acidosis with:
- pH <5.5
- Hypokalemia
- Low/normal urine pH
Type 2
Problem in type 1 RTA
DISTAL defect in alpha intercalated cells to secrete H+ (no HCO3- is generated)
Problem in type 2 RTA
Defect in PROXIMAL tubule HCO3- reabsorption results in increase excretion of HCO3- in urine
Problem in type 3 RTA
Hyperkalemia from hypoaldosteronism or K+ sparing diuretics impairs ammoniagenesis in the PT which decreases buffering capacity and decreases H+ secretion into urine
Causes of type 1 RTA
Ampho B toxicity
Analgesic nephropathy
Congenital anomalies (obstruction) or urinary tract
Causes of type 2 RTA
Fanconi syndrome (ex. Wilson disease)
Lead/aminoglycoside toxicity
Carbonic anhydrase inhibitors
Multiple myeloma (light chains)
Hyaline casts
can be normal finding (concentrated urine)
Waxy casts
Advanced (chronic) renal disease
Granular casts (muddy brown)
Acute tubular necrosis
Fatty casts (oval fat bodies)
Nephrotic syndrome
WBC casts
Tubulointerstitial inflammation
Acute pyelonephritis
Transplant rejection
RBC casts
glomerulonephritis
ischemia
malignant HTN
Pyuria no casts
Acute cystitis
Hematuria no casts
Bladder cancer
Kidney stone
Nephritic or nephrotic: Acute PSGN
Nephritic
Nephritic or nephrotic: FSGS
Nephrotic
Nephritic or nephrotic: amyloidosis
Nephrotic
Nephritic or nephrotic: MPGN
both
Nephritic or nephrotic: Alport syndrome
Nephritic
Nephritic or nephrotic: Diffuse Proliferative GN
both
Nephritic or nephrotic: RPGN
nephritic
Nephritic or nephrotic: minimal change disease
Nephrotic
Nephritic or nephrotic: IgA glomerulonephropathy
Nephritic
Nephritic or nephrotic: Membranous nephropathy
Nephrotic
Nephritic or nephrotic: Diabetic glomerulonephropathy
Nephrotic
Proteniuria level in nephrotic syndrome
> 3.5 g/day
Most common kidney stone presentation
patient with normocalcemia and hypercalciuria (calcium oxalate stone)
Which kidney stone is radiolucent?
uric acid
Enveloped shaped crystals
Calcium stones
Coffin lid crystals
Ammonium magnesium phosphate stone
Hexagonal crystals
Cystine stone
Rhomboid or rosette crystals
uric acid
Stones that precipitate at high pH
Calcium PHOSPHATE
Ammonium magnesium phosphate
Stones that precipitate at low pH
Calcium OXALATE
Uric acid
Cystine
Cause of ammonium magnesium phosphate (struvite) stones
Urease positive bug infection (proteus, staphylococcus, klebsiella, etc)
Treatment for calcium stones
thiazides
citrate
Treatment for struvite stones
eradicate infection
remove stone
Treatment for uric acid stone
alkalinizaiton of urine
Treatment of cystine stones
alkalinizaiton of urine
hydration
Causes of uric acid stones
leukemia
hyperuricemia (gout)
Causes of cystine stones
Cystinuria
Test for cystine stones
sodium nitroprusside test positive
Cystitis with ammonia smelling urine
Proteus mirabilis
Viral cause of acute infectious cystitis
Adenovirus (hemorrhagic cystitis)
What is positive in labs for acute infectious cystitis?
leukocyte esterase
Thyroidization of kidney
chronic pyelonephritis
What parts of glomerulus are most sensitive to ischemia?
proximal tubule
thick ascending limb
Type of ARF with:
Urine osmolality >500
Urine Na 20
Prerenal azotemia
Type of ARF with:
Urine osmolality 40
FENa >2%
Serum BUN/Cr <15
Intrinsic renal failure
Type of ARF with:
Urine osmolality 40
FENa >1% (mild) or >2% (severe)
Serum BUN/Cr >15 (varies)
Postrenal azotemia
Causes of prerenal azotemia
Low RBF (hypotension) so urea is retained by kidney to conserve volume
Causes of postrenal azotemia
Outflow obstruction (bilateral due to stones, BPH, neoplasia, etc)
Causes of Intrinsic renal failure
ATN or ischemia/toxins (patchy necrosis leads to debris obstructing tubule and fluid backflow across necrotic tubule which impairs BUN reabsorption)