MTB 3 - Renal Flashcards
You can differentiate chronic renal failure from acute renal failure by what 3 things?
Chronic renal failure will have:
- Small kidneys
- Drop in hematocrit from loss of erythropoietin
- Low calcium from loss of Vitamin D hydroxylation
What are 6 things that can cause prerenal azotemia?
Anything that causes hypoperfusion:
- Hypotension
- Hypovolemia
- Low oncotic pressure (low albumin)
- CHF
- Constrictive pericarditis (can’t perfuse kidney)
- Renal artery stenosis
What are the characteristics of prerenal azotemia?
- BUN:Cr > 20:1
- Urinary sodium 500
- Possible hyaline casts on urinalysis
Why does BUN increase with prerenal azotemia?
Low volume –> Increase in ADH –> increase urea absorption
Name causes of postrenal azotemia:
- Stones in bladder or ureters
- Strictures
- Cancer of bladder, prostate, cervix
- Neurogenic bladder (think DM or MS)
What are some clues to obstruction of the urinary system?
Distended bladder
Large volume diuresis with catheter placement
Bilateral hydronephrosis on ultrasound
What’s the BUN:Cr ratio for postrenal azotemia?
> 15:1
What are 3 characteristics of intrinsic kidney failure?
BUN:Cr ~ 10:1
Urine sodium >40
Urine osmolality
What are some common agents that induce renal insufficiency?
- Aminoglycosides (-mycin)
- Amphotericin
- Contrast (extremely rapid in onset)
- Chemotherapy (Cisplatin)
What is allergic interstitial nephritis?
Hypersensitivity to penicillin, sulfa, phenytoin, allopurinol, rifampin, quinolones.
Rash and fever with a rise in BUN and Creatinine
How do you diagnose interstitial nephritis?
Wright Stain or Hansel stain in urine to show eosinophils
Urinalysis shows white cells, but can’t distinguish neutrophils from eosinophils
What does rhabdomyolysis do to the potassium level?
Hyperkalemia from cellular destruction
Best initial test for rhabdo? Most accurate?
Initial: Urinalysis showing large amounts of blood with no cells seen (remember this is myoglobin)
Accuate: Urine myoglobin
What to order in pts with possible rhabdo?
Potassium level
Calcium level (low)
Chemistries looking for low bicarb
Why does rhabdo cause hypocalcemia?
Damaged muscle binds calcium
Tx of rhabdo?
- Bolus of NS
- Mannitol and diuresis to decrease contact time
- Alkalinization of urine to decrease precipitation of myoglobin at the tubule
Most urgent step in an acute case of rhabdomyolysis?
EKG b/c hyperkalemia can lead to arrhythmia with peaked T-waves
What types of crystals can cause crystal-induced renal failure?
Oxalate and uric acid
Oxalate crystals can form if someone ingests ____
Antifreeze (ethylene glycol)
What will be the acid-base disturbance with antifreeze intoxication?
Metabolic acidosis with elevated anion gap
Best test for oxalate crystals? Best treatment?
Test: Urinalysis showing envelope-shaped oxalate crystals
Treatment: Ethanol or fomepizole w/immediate dialysis
Uric acid crystals most commonly occur after what?
Chemotherapy for lymphoma (tumor lysis syndrome)
How to treat uric acid crystals?
Hydration, allopurinol, and rasburicase (breaks down uric acid)
What’s the best method to prevent contrast induced renal failure?
Hydration with normal saline and possible bicarb, NAC, or both
A slight elevation of creatinine means the loss of ___ to ___% of renal function at minimum
60-70
How do NSAIDs affect the kidney
Afferent vasoconstriction which decreases glomerular perfusion
What are 3 problems NSAIDs can cause to the kidneys?
Direct toxicity w/papillary necrosis
Allergic interstitial nephritis
Nephrotic syndrome
All forms of glomerulonephritis have what 6 characteristics?
- RBCs in urine
- RBC casts in urine
- Mild proteinuria (
Goodpasture’s sxs:
Cough
Hemoptysis
SOB
Lung findings
Best initial and most accurate tests for Goodpastures?
Initial: Anti-basement membrane antibodies
Accurate: Renal biopsy showing Linear deposits
Tx of Goodpastures?
Plasmapheresis and steroids
Churg-Strauss sxs:
Asthma
Cough
Eosinophilia
Renal abnormalities
Best initial test and most accurate test for Churg-STrauss?
Initial: CBC for eosinophil count
Accurate: Biopsy
Tx for Churg-Strauss?
Glucocorticoids (prednisone)
-Add cyclophosphamide if there’s no response
Wegener’s granulomatosis sxs?
Upper and lower respiratory problems (sinusitis, otitis)
Lung (cough, hemoptysis, abnormal CXR)
Systemic vasculitis (joint, skin, eye, brain, GI problems)
upper and lower respiratory involvement + renal involvement Often misdiagnosed as pneumonia
Best initial test for Wegener’s? Most accurate?
Initial: c-ANCA
Accurate: Biopsy of kidney
Best treatment for Wegener’s?
Cyclophosphamide and steroids
What is PAN?
Systemic vasculitis affecting every organ EXCEPT the lungs.
- Renal
- Myalgias
- GI bleeding and abdominal pain
- Purpuric skin lesions
- Strokes
- Uveitis
- Neuropathy
Key to diagnosis of PAN?
Multiple motor and sensory neuropathy with pain
Best initial test and most accurate test for PAN?
Initial: ESR and markers of inflammation
Accurate: Biopsy of sural nerve or the kidney
What to always additionally test for with PAN?
Hep B and C
Best therapy for PAN?
Cyclophosphamide and steroids
How does IgA nephropathy present?
Painless recurrent hematuria in an Asian pt usually after a viral URI.
Best test for IgA nephropathy?
Renal biopsy is essential
Tx of IgA nephropathy?
No proven effective therapy that reverses it
- Steroids in boluses for sudden worsening of proteinuria
- ACE-i for all pts with proteinuria
In whom does Henoch-Schonlein purpura present? What are the sxs?
Adolescent or child
- Raised, nontender, purpuric skin lesions (buttocks usually)
- Abdominal pain
- Joint pain
- Renal involvement
- Bleeding
Diagnostic testing for HSP?
Almost always a clinical diagnosis (GI, joint, skin, and renal involvement is best indicator)
Biopsy is the most accurate test showing IgA deposition but this isn’t a test you need to do.
Tx of HSP?
Resolves spontaneously
Sxs of PSGN?
Dark urine (tea or cola colored)
Periorbital edema
HTN
What leads to PSGN?
Throat and skin infections
Best initial and most accurate test for PSGN?
Initial: Antistreptolysin O, anti-DNase, antihyaluronidase in blood
AccuratE: Biopsy (don’t do this routinely)
Treatment of PSGN?
Penicillin and other antibiotics
Diuretics for fluid overload
PResentation of cryoglobulinemia:
Renal involvement, joint pain and purpuric skin lesions in pts with a hx of Hep C
Best initial and most accurate test for cryoglobulinemia?
Initial: Serum cryoglobulinemia component levels (immunoglobulins and light chains, IgM)
Accurate: Biopsy
Tx of cryoglobulinemia?
Ledipasvir and sofosbuvir for type 1
Drug induced lupus spares what 2 organ systems?
Brain
Kidneys
For lupus nephritis, what’s the best initial test and most accurate test?
Initial: ANA and anti-double stranded DNA
Accurate: Renal biopsy (very important b/c it determines extent of disease which guides therapy)
Tx of lupus nephritis?
Sclerosis only: No tx
Mild disease: Steroids
Severe: Mycophenolate mofetil and steroids
Alport syndrome presentation? Tx?
Congenital eye and ear problems like deafness
Renal failure in 2nd or 3rd decade of life
No therapy
HUS triad:
Intravascular hemolysis (fragmented cells on smear)
High creatinine
Thrombocytopenia
TTP pentad?
HUS + Fever + Neuro abnormalities
Tx of TTP and HUS?
Plasmapheresis
Nephrotic syndrome labs:
> 3.5 g of protein lost in urine everyday
Low albumin (causes edema)
Hyperlipidemia
Thrombosis b/c loss of antithrombin III, Protein C and S
Best initial diagnostic test for nephrotic syndrome?
Urinalysis showing high protein level
Next best test for nephrotic syndrome?
Spot-urine for protein:creatinine ratio >3.5:1
OR
24-hr urine protein collection showing >3.5 g protein
Most accurate test for nephrotic syndrome?
Renal biopsy
Give the common pts these types of nephrotic syndromes occur in:
- Minimal change
- Membranous
- Membranoproliferative
- Focal segmental
- Minimal change - children
- Membranous - Adults w/cancer like lymphoma
- Membranoproliferative - Hep C
- Focal segmental - HIV, heroin use
Tx of nephrotic syndromes?
Steroids
-Cyclophosphamide if no response
If pt has mild proteinuria, what do you do first?
Repeat urinalysis b/c it often disappears on repeat
What if pt has mild proteinuria on repeat testing?
Make sure they don’t have a reason for transient proteinuria:
- CHF
- Fever
- Exercise
- Infection
What if the above reasons are not present when they have mild proteinuria?
Possible orthostatic proteinuria
-Ppl who stand all day like waiters, teachers, etc
How to diagnose orthostatic proteinuria?
Take morning urine protein and then afternoon protein.
-If present in afternoon and not morning its orthostatic
What if the morning protein is elevated as well?
Do 24-hr urine or spot protein:cr ratio. If elevated do biopsy
Describe the overall steps in the workup of proteinuria:
- Repeat UA
- Evaluate for othostatic proteinuria
- Get protein/cr ratio
- Get renal biopsy
Give 4 manifestations of uremia and their treatment:
- Hyperphosphatemia - calcium acetate/carbonate
- Hypermagnesemia: Mg restriction in diet
- Anemia: erythropoietin replaceent
- Hypocalcemia: Vit D replacement
When do you need dialysis?
- Metabolic acidosis
- Hyperkalemia
- Intoxication with lithium, aspirin, or ethylene glycol (dialyzable drugs)
- Fluid overload
- Uremic encephalopathy
Name the two types of diabetes insipidus
Central: Brain not making ADH
Nephrogenic: Kidney can’t respond to ADH
These both cause hypernatremia
What things can cause nephrogenic DI?
Hypokalemia
Hypercalcemia
Lithium toxicity
Sxs of hypernatremia and hyponatremia:
Confusion
Seizures
Coma
First thing to do in a pt with hyponatremia?
Assess volume status
Causes of hypervolemic hyponatremia?
CHF
Nephrotic syndrome
Cirrhosis
Causes of hypovolemic hyponatremia:
Diuretics - High urine sodium GI loss (vomiting, diarrhea) - Low urine sodium Skin loss (burns, sweating) - Low urine sodium
Causes of euvolemic hyponatremia:
SIADH
Hypothryoidism
Psychogenic polydipsia
Hyperglycemia
How are glucose and sodium levels associated?
Every 100mg of glucose above normal drops the sodium by 1.6
What labs does Addison’s disease give?
It’s low aldosterone, so:
- Hyponatremia
- Hyperkalemia
- Metabolic acidosis
Tx with fludrocortisone
What can cause SIADH?
Any CNS abnormalities
Any Lung disease
Sulfa, SSRI, carbamazepine
Cancer
How to treat mild hyponatremia with no sxs:
Fluid restriction
How to treat moderate to severe hyponatremia (confusion, seizures)
Saline infusion with loop diuretics
Hypertonic (3%) saline
Check Na frequently
ADH blockers (conivaptan, tolvaptan)
How fast to correct hyponatremia?
No more than 10-12 in 1st 24 hours
Central pontine myelinolysis
How to tx chronic SIADH from malignancy?
Demeclocycline to block ADH affect at kidney
What usually causes hyperkalemia?
Rhabdo or hemolysis
Can you get hyperkalemia from diet?
Yes, but only if your kidneys aren’t working well. The kidney excretes it faster than the GI tract can even absorb it
Give 10 other causes of hyperkalemia:
- Hypoaldosteronism (Addison’s disease)
- Metabolic acidosis
- Beta blockers
- Digoxin toxicity
- Insulin deficiency
- Spironolactone, eplerenone
- ACE-I and ARBs
- Prolonged immobility, seizures, rhabdo, crush injury
- Type IV renal tubular acidosis
- Renal failure
EKG of hyperkalemia?
1st come the Peaked T-waves
2nd comes loss of P-wave
3rd comes widened QRS
How to treat severe hyperkalemia (As evidenced by EKG chnages like peaked-T-waves)
Start with: IV calcium gluconate
Followed by: IV insulin and glucose*
Then finish it up with: Kayexalate
How to fix moderate hyperkalemia (no EKG abnormalities)?
IV Insulin and glucose
Bicarb to shift K into cells
Kayexalate orally to remove from body (takes hours)
Give 7 causes of hypokalemia:
- Dietary insufficiency
- Diuretics
- High-aldosterone states (Conn syndrome)
- Vomiting (metabolic alkalosis which shifts K into cells)
- Proximal and distal RTA
- Amphotericin
- Bartter syndrome (Loop of Henle can’t absorb sodium and chloride –> secondary hyperaldosteronism)
What rhythm disturbance does Hypokalemia give?
U-waves
Tx of hypokalemia?
Replace potassium orally (no maximum rate)
Avoid glucose-containing fluids
Most common cause of hypermagnesemia?
Overuse of laxatives that contain Mg or iatrogenic administration when used as a tocolytic
Sxs of hypermagnesemia?
Muscular weakness
Loss of DTRs
Tx of hypermagnesemia?
Restrict intake
Saline administration to provoke diuresis
Occasionally dialysis
6 causes of hypomagnesemia:
- Loop diuretics
- Alcohol withdrawal or starvaton
- Gentamicin, amophotericin
- Cisplatin
- Parathyroid surgery
- Pancreatitis
Presentation of hypomagnesemia?
Hypocalcemia and cardiac arrythmias
Name the 7 causes of metabolic acidosis with an increased anion gap:
- Lactic acidosis
- Aspirin overdose
- Methanol
- Uremia
- DKA
- Isoniazid toxicity
- Ethylene glycol
Methanol causes production of what?
Formic acid and formaldehyde
Tx of methanol intoxication?
Get a methanol level
Order fomepizole or ethanol
In DKA, what’s the fastest single test to tell if a patient’s hyperglycemia is life-threatening
Low bicarbonate
Causes of meatbolic acidosis with a normal anion gap?
Diarrhea
RTA
Name 5 things that cause a metabolic alkalosis:
Volume contraction Conn syndrome or Cushing syndrome Hypokalemia Milk-Alkali syndrome Vomiting
How does volume contraction lead to a metabolic alkalosis?
Because it causes secondary hyperaldosteronism which causes increased urinary excretion of acid
What is another name for primary hyperaldosteronism?
Conn syndrome
How does hypokalemia cause a metabolic alkalosis?
Potassium ions shift out of the cell to correct the hypokalemia. Thsi shifts hydrogen ions into the cell.
What is milk-alkali syndrome?
Too much liquid antacid
Man is found to have a BP of 145/95 on a routine visit. What’s the next step?
Repeat in 1-2 weeks
What should you also order when you diagnose someone with HTN?
Urinalysis
EKG
Eye exam
Cardiac exam
Most effective lifestyle modification for HTN?
Weight loss
When starting an antihypertensive, which drug will you choose if a pt has:
- CAD
- CHF
- Migraine
- Hyperthyroidism
- Osteoporosis
- Depression
- Asthma
- Pregnacy
- BPH
- DM
- CAD - Beta blocker
- CHF - Beta blocker, ACEI/ARB
- Migraine - Beta blocker, CCB
- Hyperthyroidism - Beta blocker
- Osteoporosis - Thiazide
- Depression - No beta blockers
- Asthma - No beta blockers
- Pregnacy - Alpha methyldopa
- BPH - Alpha blockers
- DM - ACEI/ARB
BP target for those >60 years old?
150/90
When to investigate for secondary hypertension?
- Pt is 60
- Failure to control BP with 3 meds
- If pt has
- Bruit
- Episodic HTN
- Buffalo hump, truncal obesity
- Upper extremity > lower extremity pressure
- Hirsutism
- Hypokalemia
When a pt with HTN has each of these, what will you think of?
- Bruit
- Episodic HTN
- Buffalo hump, truncal obesity
- Upper extremity > lower extremity pressure
- Hirsutism
- Hypokalemia
- Bruit = Renal artery stenosis
- Episodic HTN = Pheo
- Buffalo hump, truncal obesity = Cushing
- Upper extremity > lower extremity pressure = Coarctation
- Hirsutism = CAH
- Hypokalemia = Conn syndrome
Describe renal artery stenosis
Bruit in the flanks or abdomen
Hypokalemia may be present
How to diagnose renal artery stenosis?
Initially: Renal U/S
Most accurate: Renal angiogram
Best treatment for renal artery stenosis?
Renal artery angioplasty and stenting
