Renal Flashcards
Most sensitive screen for diabetic nephropathy
Urine Microalbumin:Creatinine ratio
Small bilateral kidneys
Chronic HTN
Prevention of contrast induced nephropathy (CIN)
Pre-CT IVF
(+ acetylcysteine)
Post-cardiac cath AKI
Cholesterol emboli vs. CIN (contrast-induced nephropathy)
- CIN resolves within 3-7d
- Cholesterol emboli can be immediate or delayed >30d
Causes of primary adrenal insufficiency
Autoimmune vs. TB
TB is a common cause of
Primary adrenal insufficiency
Na+, K+, and H+ in primary adrenal insufficiency
Hyponatremia, hyperkalemia, and NAGMA (decreased aldosterone)
Painless gross hematuria
Bladder cancer
Red urine negative for RBCs
Myoglobinuria vs. Beet ingestion vs. Rifampin
Lithium polyuria
Nephrogenic DI
(renal ADH resistance)
Tx: Discontinue Lithium + Salt restriction
Common complications of ADPKD
IC berry aneurysms, hepatic cysts
Potassium citrate
Alkalinization of urine
Uric acid stones diet
Low-protein diet
(low-purine diet)
Cause of refractory hypokalemia
Hypomagnesemia
Tamsulosin
α-1 blocker
(tx of ureteral kidney stone)
C3 dense deposits in glomerular BM due to persistent activation of the alternative complement pathway
MPGN
(persistently low C3)
Causes of Papillary Necrosis
NSAID:
NSAIDs, SCD, Analgesic abuse, Infection (pyelo), DM
Acute hypercalcemia Tx
Aggressive NS hydration + Calcitonin
Bisphosphonates in acute hypercalcemia
NEVER choose this. Effect is 2-4d delayed.
Increased bleeding in CKD
Uremic coagulopathy
(platelet dysfunction —> Increased BT)
Cocaine abuse + elevated CPK & K+
Renal failure
(myoglobin-induced ATN in setting of rhabdomyolysis)
Tx:
- Aggressive hydration
- Mannitol
- Urine Alkalinization (potassium citrate)
Kidney biopsy w/ increased extracellular matrix, basement membrane thickening, mesangial expansion, and fibrosis
Diabetes Mellitus
Kidney biopsy w/ intimal thickening, luminal narrowing of renal arterioles, and e/o sclerosis
Hypertension
(arteriosclerosis + capillary tufts)
Most common cause of death in dialysis patients
Cardiovascular disease
(SCD then acute MI)
Needle-shaped crystals on CT
Uric acid stones
- Rhomboid or Rosette on microscopy (uRhomboid acid)
- Acidic pH
- Radiolucent (transparent) on XR
- Tx: Urine Alkalinization + Allopurinol
Tx of Hypercalcemia:
- NS hydration (first step)
- Calcitonin (inhibit bone resorption)
- Bisphosphonates
Euvolemic hyponatremia + HIGH urine Osm + HIGH urine sodium
SIADH
Tx of post-operative urinary retention (PUR)
Urgent bladder scan & catheterization!
Nodular glomerulosclerosis
Pathognomonic change in diabetic nephropathy
(Diabetic GN)
Cervical motion tenderness
PID
Metformin should be discontinued in pts w/ renal failure, liver failure, or sepsis as it can cause ____
Lactic acidosis
IBD predisposes to this type of nephrotic syndrome
Amyloidosis (AA)
RA predisposes to
Amyloidosis (AA)—abnormal proteins
Hyalinosis of afferent and efferent glomerular arterioles on LM
Diabetic nephropathy
Incontinence in uncontrolled diabetes
Diabetic autonomic neuropathy
(DAN)
Congo Red staining and Apple Green birefringence in polarized light
Amyloidosis
(staining of glomerular deposits)
Earliest renal abnormality in diabetic nephropathy
Glomerular hyperfiltration, followed by:
- Glomerular basement thickening
- Mesangial expansion (creating broad casts)
- Nodular glomerulosclerosis (pathognomonic for DM [Kimmelsteil-Wilson nodules])
Associated with HBV
PAN
(Polyarteritis Nodosa: small- to medium-sized vasculitis)
Associated with HCV
Cryoglobulinemia
(HSP-like adult syndrome w/o GI)
Associated with Cryoglobulinemia
HCV
Test all pts with mixed cryoglobulinemia for ____
HCV
HSP-like renal disease in adults w/ HCV
Mixed cryoglobulinemia
GFR when uremic symptoms may occur
GFR <60
Tx for symptomatic uremia
Dialysis!
(encephalopathy, pericarditis, or bleeding)
Indications for urgent dialysis
AEIOU
- Acidosis <7.1 refractory to medical therapy
- Electrolyte abnormalities (severe hyperkalemia, >6.5 refractory to medical therapy)
- Intoxication (ASA, methanol/ethylene glycol, lithium, valproic acid/carbamazepine)
- Overload (e.g. CKD; refractory to diuretics)
- Uremia (Symptomatic [encephalopathy, pericarditis, bleeding; usually will have GFR <60)
Chlorthalidone is a _____
thiazide diuretic
Thiazide diuretic effects →
- Decreased K+ (hypokalemia)
- Decreased Mg2+ (hypomagnesemia)
- Decreased Na+ (hyponatremia)
- Increased Ca2+ reabsorption (hypercalcemia)
- Increased glucose (hyperglycemia)
- Increased uric acid (hyperuricemia; predisposed to gout)
- Increased LDL & TGs
Contrast is required/not required to visualize ureteral stones (abd CT)
Not required
Lower abd pain that radiates to groin
Obstructive ureterolithiasis
(kidney stone)
Winter’s Formula is used to
calculate respiratory compensation for metabolic acidosis
(pCO2 = 1.5(HCO3) + 8 ± 2)
ASA causes mixed respiratory alkalosis & metabolic acidosis by directly stimulating the ____ and decreasing ____ respectively
- medullary respiratory center (tachypnea)
- renal elimination of lactic acid & ketoacids (& increased production)
Low C3, Normal C4
PSGN
Persistently Low C3, Normal C4
MPGN
Low C3 & C4
SLE
Higher Ca2+ concentrations required to suppress PTH release due to AD mutation of Ca2+-sensing receptor (CaSR)
FHH
(Familial Hypocalciuric Hypercalcemia)
Drug that causes red to orange discoloration of body fluids (urine, saliva, sweat, tears)
Rifampin
(also causes AIN)
High-dose TMP-SMX requires serial monitoring of ____
K+ levels
MOA of ADH stimulation from hypovolemia
Stretch receptors in LA
MOA of ADH stimulation from decreased renal perfusion
Angiotensin II
MOA of ADH stimulation from hypotension
Baroreceptor stimulation in carotid arteries
____ stimulates thirst
Angiotensin II
Decreased skin turgor
Hypovolemia
“Red Urine”
Rifampin
Elevated urinary sodium AND potassium
Diuretic use/abuse
Pre-renal causes:
- Decreased EABV (HF, Cirrhosis)
- Displaced intravascular fluid (sepsis, pancreatitis)
- Decreased afferent flow (RAS, NSAIDs)
Small bowel disease malabsorption of fatty acids and bile salts can predispose to ____ kidney stones
calcium oxalate
(Unabsorbed fatty acids chelate with calcium, freeing up oxalic acid for absorption)
Coffin-lid
(stud-shaped) kidney stone
Struvite
Kidney stone caused by infection w/ urease+ bugs
(Proteus mirabilis, Klebsiella, Staph saprophyticus)
Staghorn calculi
(struvite—ammonium magnesium phosphate stone)
caused by bacterial conversion of urea to ammonia
Tx: Abx + Surgery
Tx of calcium oxalate kidney stones
- IVF
- Low sodium diet
- Thiazides (prevent hypercalciuria)
- Citrate (lowers insoluble calcium oxalate formation)
Dumbell-shaped crystals
Calcium oxalate
(alternatively “envelope-shaped”)
Rhomboid or rosette-shaped stones
Uric acid stones
Radiolucent (transparent) on XR and CT
- Uric acid stones (visible on US)
- Cystine stones
Hexagonal kidney stones
Cystine stones
(AR cystinuria; +sodium cyanide nitroprusside test)
Acidic urine predisposes to ____ kidney stones
- Uric acid stones
- Cystine stones (AR cystinuria—sodium cyanide nitroprusside test+)
- Tx for both: Alkalinization of urine
- +allopurinol for UA stones and low Na+ diet for cystine stones
Kidney stones are radioopaque on CT and XR
- Calcium oxalate
- Calcium phosphate
- Struvite (ammonium magnesium phosphate)
___ kidney stones occur in dehydration and acidic urine
Uric acid stones
____ kidney stones are common in primary hyperparathyroidism
Calcium phosphate
75-90% of kidney stones are composed of ____
Calcium oxalate
Renal stones measuring less than ___ in diameter typically pass spontaneously w/ conservative management (IVF >2L/day & analgesia)
5mm
Acyclovir can cause ____ if adequate hydration/IVF is not also provided
Crystalline nephropathy w/ renal tubular damage
Chronic diarrhea leads to metabolic ____
alkalosis
(due to loss of bicarbonate)
Contraction alkalosis
when aldosterone increases to restore intravascular volume, which leads to urinary H+ loss in the process
- Aldosterone functions to retain water by pulling in bicarb at the expense of excreting both potassium and acid in the urine.
Respiratory alkalosis induced by mechanical hyperventilation is compensated by _____
the kidney preferentially excreting bicarbonate in the urine
(high urine pH)
Decreased renal perfusion in hepatorenal syndrome is due to ____
afferent vasoconstriction 2/2 splanchnic vasodilation
· Tx for prevention of recurrent calcium oxalate kidney stones
- Diet recs: Increased fluid intake, decreased sodium intake, and normal calcium intake
- Sodium-restricted diet (low sodium promotes sodium & calcium reabsorption thru effect on medullary concentration gradient)
- HCTZ (reduces Ca2+ excretion; use in pts w/ hypercalciuria)
Anticholinergic treatment for detrusor instability in uninhibited detrusor contractions (urge incontinence)
Oxybutynin
Stress incontinence Tx
Kegels, Duloxetine, Pseudoephedrine
Neurogenic bladder Tx
Bethanechol
(cholinergic agonist)
or Intermittent urethral catheterization
Normal PVR (Post-Void Residual)
<150mL in women, <50mL in men
(rules out urinary retention)
Crystal-induced AKI w/ renal tubular injury/obstruction
- Acyclovir
- Sulfonamides
- MTX
- Ethylene glycol (rectangular envelope-shaped)
- Protease inhibitors
Acyclovir renal complication
Crystal-induced AKI w/ intratubular obstruction (Always give w/ IVF!)
Drug-reaction AKI
AIN
(Pee, Pain-free, PCN, PPI, rifamPin)
- +Cephalosporins
- +TMP-SMX
- +Pyuria, +Azotemia
Benign recurrent hematuria
Thin basement membrane nephropathy
(familial isolated microscopic hematuria, aka Benign Familial Hematuria)
Anti-GBM antibodies
Pulmonary renal syndrome
(Goodpasture’s)
XL defect in collagen IV formation w/ ocular abnormalities & hematuria
Alport syndrome
(+hearing loss, +progressive renal insufficiency)
Post-infectious hematuria 10-21d post-pharyngitis
PSGN
(low C3, elevated ASO ± anti-DNAse B)
Post-URI hematuria (within 5 days)
IgA Nephropathy
(normal complement levels)
Rectangular envelope-shaped crystals w/ AGMA
Calcium oxalate crystals
(ethylene glycol poisoning [antifreeze] in setting of AGMA)
Diarrhea effect on serum potassium
Hypokalemia
Decreased mineralocorticoid activity effect on serum potassium
Hyperkalemia
(Hyperaldosteronism excretes K)
Acidosis effect on serum potassium
Hyperkalemia
Insulin effect on serum potassium
Hypokalemia
(C BIG K)
Albuterol effect on serum potassium
Hypokalemia
(part of C BIG K DD tx for hyperK+)
BBs effect on serum potassium
Hyperkalemia
Very nephrotoxic antibiotics
Aminoglycosides
(STANKG)
Tx for cyanide toxicity
Sodium thiosulfate
Prolonged hypovolemic shock renal injury
ATN
(muddy brown casts)
Muddy brown granular cast
ATN
pathognomonic)
RBC casts
Glomerulonephritis, Malignant HTN
WBC casts
Interstitial nephritis, Pyelonephritis, Transplant rejection
Fatty casts
(“oval fat bodies”)
Nephrotic syndrome
(assoc. w/ “Maltese cross” sign)
Broad & waxy casts
Chronic renal failure
Hyaline casts
Normal or ASx prerenal azotemia
Renal vein thrombosis presentation
Abd pain + hematuria
MPGN
HCV infection
Bland urine sediment
no red cells, casts, or protein
(no intrinsic renal pathology)
Very low urine sodium level
Prerenal: FENa <1% or <10mEq/L —> Hepatorenal syndrome renal failure
(renal hypoperfusion), dehydration, etc.
Eosinophils in urine
Interstitial nephritis (AIN)
- Think drug reaction (hapten-like drugs; 5 P’s)
- +pyuria, +azotemia
- Pee (diuretics)
- Pain-free (NSAIDs)
- PCN or cephalosporins
- PPI
- rifamPin
Metabolic alkalosis w/ low urine chloride (<20 mEq/L)
Saline-responsive metabolic alkalosis:
- Surreptitious vomiting
- NG aspiration
- Prior diuretic use
Metabolic Alkalosis w/ high urine chloride (>20mEq/L)
Saline-unresponsive metabolic alkalosis:
Hypovolemic:
- Current diuretic use (this one is saline-responsive)
- Bartter syndrome
- Gitelman syndrome
Hypervolemic = excess mineralocorticoid activity
- Primary hyperaldosteronism
- Cushing disease
- Ectopic ACTH production
Black licorice ingestion
“hyperaldosteronism” presentation
Hyperkalemia-causing drugs:
ACE-I/ARBs, BBs
(nonselective), K-sparing Diuretics, NSAIDs
AGMA
MUDPILES
- Methanol (formic acid)
- Uremia
- DKA
- Propylene glycol
- INH or Iron tablets
- Lactic acidosis
- Ethylene glycol (—> —> oxalic acid)
- Salicylates (late)
NAGMA
HARDASS
Hyperalimentation
Addison disease
RTA
Diarrhea
Acetazolamide
Spironolactone
Saline infusion
Metabolic Alkalosis:
LVAH
Loop diuretics
Vomiting (Tx: NS infusion)
Antacid use
Hyperaldosteronism (Tx: aldosterone antagonists)
Respiratory Alkalosis:
Hyperventilation
- Hysteria
- Hypoxemia (high-altitude)
- Salicylates (early)
- Tumor
- PE
Respiratory Acidosis:
Hypoventilation
- Airway obstruction
- Acute or chronic lung disease
- Opioids, sedatives
- Weakening of respiratory muscles
Urinary protein excretion >3.5g/day
Nephrotic proteinuria
High water channels
SIADH
(too much ADH)
SIADH vs. Diabetes Insipidus
SIADH:
Too much ADH, excessive water retention; DI: Not enough ADH; excessive water loss
Urine osmolality <100
Dilute urine
- Primary polydipsia, or
- Beer potomania (malnutrition–poor dietary solute intake mixed w/ excessive intake of alcohol)
Urine osmolality in increased ADH
Increased
(concentrated)
Urine osmolality > Serum osmolality
Concentrated urine
2/2 dehydration and increased ADH; or hyponatremia
Recurrent stones
- Cystinuria (cystine)
- Klebsiella UTI (Struvite stone formation)
- Parathyroid adenoma
Dipstick+ for leukocyte esterase
Pyuria in urine
Dipstick+ for nitrites
E. Coli
Hexagonal crystals on UA
Cystinuria
(inherited recurrent kidney stones)
- Acidic pH
- Radiolucent (transparent on XR)
- Begins in childhood (usually)
- Dx: Sodium cyanide nitroprusside test
- Purple urine within 2-10 min: Positive test (aminoaciduria)
- Cyanide converts cystine to cysteine; nitroprusside binds w/ cysteine, producing purple color
- Tx: Urine Alkalinization + Low sodium diet
Cyanide nitroprusside test
Cystinuria
(recurrent kidney stones)
- Purple urine = Positive test = Aminoaciduria
Nephrotic syndrome (adults)
Focal Segmental Glomerulosclerosis
(FSGS)
Nephrotic syndrome (kids)
Minimal change disease
Nephrotic syndrome (Hodgkins)
Minimal change disease
Nephrotic syndrome
(lung/breast/prostate/colon malignancy)
Membranous Glomerulonephropathy
Nephrotic syndrome (Multiple Myeloma)
Amyloidosis
Renal disease in HBV or HCV
MPGN
Hyperkalemia Tx
C BIG K DD
- Calcium gluconate (IV)
- Bicarbonate/Beta-agonists (albuterol)
- Insulin
- Glucose
- Kayexalate
- Diuretics
- Dialysis
- Cation Exchange Resins (Polystyrene)
Fever, tinnitus, tachypnea
Salicylate toxicity (ASA)
Tx: Sodium bicarbonate
Kussmaul breathing (deep, rapid)
DKA
(T1DM)
Metabolic acidosis after seizure is due to:
Postictal lactic acidosis
(MUDPILES)
- Transient & self-ltd AGMA, resolves within 90 minutes
Pt w/ nephrotic syndrome is at most risk for:
HypercOagulability 2/2 renal loss of ATIII
(PrOteinuria, HypOalbuminemia, Edema, HLD)
- Renal vein thrombosis (most common complication)
- Pulmonary embolism
- Other thromboses
- Protein malnutrition (hypoalbuminemia 2/2 renal loss)
- Iron-resistant hypochromic microcytic anemia
- Increased susceptibility to infection
- Vitamin D deficiecny (loss of cholecalciferol-binding protein)
- Decreased thyroxin (loss of thyroxin-binding globulin)
Sodium nitroprusside infusion
Cyanide toxicity
- AGMA (MUDPILES) from lactic acidosis 2/2 cellular shift to anaerobic metabolism due to cyanide binding to cytochrome oxidase (inhibiting oxidative phosphorylation in mitochondria)
- Can occur from combustion of carbon-containing compounds (house fires, wool, silk), industrial exposure (metal extraction in mining), or IV infusion of sodium nitroprusside
- p/w:
- Tx: Sodium thiosulfate
WBC casts, pyuria, eosinophiluria
AIN (drug-induced interstitial nephritis)
- 5 P’s
- TMP-SMX (sulfas)
- AlloPurinol
- Loops & thiazides (sulfas, except the loop, ethacrynic acid)
- Tx: Discontinue agent
Only non-sulfa loop diuretic
Ethacrynic Acid
Scrotal varicoceles are almost always left-sided because
- L gonadal vein drains into the L renal vein, which then drains into the IVC
- In contast, R gonadal vein drains directly into the IVC
- Thus, any renal pathology on left side can p/w L varicocele if obstruction is involved (e.g. RCC)
Left-sided varicocele that does not reduce (empty) when pt is recumbent (lying down)
RCC
- Obstruction of venous flow due to L gonadal vein draining into renal vein before IVC
- CT abd
Quickest way to lower potassium levels in hyperkalemia
Insulin + Glucose drip
(creates rapid intracellular shift)
- +beta agonist if no CVD
Diabetic w/ urinary retention & high post-void residual volume (>50 mL)
Neurogenic bladder
(from DAN [Diabetic Autonomic Neuropathy]; Overflow incontinence)
- Pt has decreased ablity to sense full bladder
- Can p/w continuous dribbling (day or night), incomplete emptying, distended bladder, overflow incontinence
Most common cause of AL amyloidosis (Primary)
Multiple Myeloma
- Also seen in Waldenström macroglobulinemia
- Light chain accumulation (Lambda)
Most common cause of AA amyloidosis (2o)
Rheumatoid Arthritis
RA + nephrotic syndrome
AA Amyloidosis (2o)
- Congo Red Apple Amyloid
- Amyloid Apple Green Birefringence under Polarized Light
Pelvic pain exacerbated by a full bladder and relieved by voiding
Interstitial Cystitis
(Painful bladder syndrome)
- Bladder pain w/ no other cause for >6 weeksChronic pelvic pain
- Urinary urgency & frequency
- Dyspareunia
- Normal UA
- Tx = Palliative: Trigger avoidance, amitryptiline, & analgesics for pain flares
Bleeding + very high BUN
Uremic coagulopathy
(Platelet dysfunction 2/2 uremic toxins)
- PT, PTT & platelet count normal
- BT prolonged
- Tx: DDAVP (desmopressin)
- Increases release of Factor VIII:vWF multimers from endothelial storage sites
- Platelet transfusion not indicated b/c transfused platelets become inactive
Facilitates kidney stone passage
Alpha blockers
(tamsulosin)
- Alpha receptors found on distal ureter, base of the detrusor, bladder neck, & urethra
The magnesium gate protects ____ from being excreted by the kidneys
Potassium
- ROMK channels (Renal Outer Medullary Potassium) in collecting tubules inhibit K+ secretion.
- Hypomagnesemia leads to excessive renal potassium wasting & refractory hypokalemia
- Common in chronic alcoholics
Hypomagnesemia’s effect on potassium & effect on reflexes?
- Potassium loss by kidneys (ROMK channels [potassium gate] are held closed by Mg2+) → Refractory hypokalemia (common in chronic alcoholics)
- Hyperactive reflexes
Infraumbilical fullness
Urinary retention
- Urinary catheterization & d/c amitriptylene
- >50mL
- Usually from Anticholinergics (amitriptylene [TCAs]), BPH, post-anesthesia, etc.
Intermittent episodes of high-volume urination
Post-obstructive diuresis
(2/2 obstructive uropathy due to nephrolithiasis)
- Occurs when urinary obstruction (from renal calculi) is overcome by a large volume of retained urine
- Excessive diuresis may lead to potassium wasting (mild hypokalemia) & dehydration
- Pt p/w flank pain, low-volume voids (w/ or w/o occasional high-volume voids), & renal dysfunction if BL
Psych patient w/ hyponatremia & low uOsm (<100 mOsm)
- Primary Polydipsia (increased thirst 2/2 central defect in thirst regulation)
- Malnutrition (beer potomania–low solute intake 2/2 excessive beer intake)
Nephrotic proteinuria, hematuria, dense deposits stained for C3
MPGN, Type 2
(aka “Dense deposit disease”)
- Caused by IgG Abs against C3 convertase, leading to persistent activation of the alternative complement pathway & kidney damage
Horseshoe kidney
Turner Syndrome (XO)
25M w/ weak urine stream and incomplete emptying of bladder. MCC?
Urethral stricture
(a fibrotic narrowing of the urethra 2/2 trauma, infection, or radiotherapy)
- Dx: Urethrography or cystourethroscopy
- ↑ Postvoid residual volume
- Tx: Urethral dilation or Surgical urethroplasty
Severe LLQ abd pain radiating to the groin, vomiting, and soft nontender abdomen on exam
Ureterolithiasis
- Severe flank pain that radiates to the perineum, penis, scrotum, or inner thigh
- Colicky in nature & poorly localized
- Pts often writhing in pain and unable to sit still, but benign abd exam
- Dx: Abdominal U/S
Presents similarly to nephrolithiasis but w/ enlarged kidney and ↑LDH
Acute Renal Vein Thrombosis
- Dx: CT Angiography (or MR Angiography), Renal venography
- Usually occurs in setting of nephrotic syndrome due to urinary loss of anticoagulant proteins & alteration of hemostatic balance, but can also occur w/ acquired hypercoagulability a/w malignancy or trauma.
(RVT)
When giving pt acyclovir, always give
IVF
due to risk of crystalluria w/ renal tubular obstruction (crystal-induced AKI) due to the drug’s low urine solubility and how it easily precipitates in renal tubules causing intratubular obstruction and direct renal tubular toxicity.
- Note: This is more common specifically w/ High-Dose IV Acyclovir, and occurs only rarely with oral acyclovir.
Muddy brown granular cast
Acute Tubular Necrosis
(ATN)
Red blood cell casts
Glomerulonephritis
White blood cell casts
Interstitial nephritis and pyelonephritis
Fatty Casts
Nephrotic Syndrome
Broad & Waxy Casts
Chronic Renal Failure
When to medically manage ureteral stones (instead of urology consult / lithotripsy)
- <10mm
- No urosepsis (e.g. fever, AMS)
- No acute renal failure
- No complete obstruction
Medical Management:
- Hydration
- Pain control
- Alpha blockers (e.g. tamsulosin)
- Strain urine
Scars/calluses on the dorsum of the hands
Dental erosions
Surreptitious vomiting
- Low urine chloride 2/2 hypochloremia from ↑ vomiting
- In diuretic abuse, Bartter syndrome, & Gitelman’s syndrome, urine chloride will be high
Hematuria following a URI
IgA Nephropathy
(or PSGN)
