Renal/GU (5%) Flashcards
Acute Kidney Failure
Sudden decrease in kidney function resulting in the inability to maintain acid-base, fluid, and electrolyte balance, and to excrete waste
Causes can be pre-, intra-, or post-renal and treatment depends on the cause
Pre-renal acute kidney failure
40-80% of cases
Causes – decrease in intravascular volume, decreased CO, hypotension
BUN/creatinine ratio > 20:1
Treatment – increase renal blood flow (fluids, hydration)
Intra-renal acute kidney failure
50% of cases
Causes – renal ischemia, nephrotoxic injury
Intra-renal failure can lead to ischemic injury when MAP < 60 or circulation is interrupted for > 30 minutes
BUN/creatinine ratio of < 10:1
Treatment – rule out pre- and post-renal causes first, remove offending agent/cause of ischemia, hydrate
Post-renal acute kidney failure
5-10% of cases
Causes – obstruction
BUN/creatinine ratio of 10:1-20:1
Treatment – relieve obstruction, hydrate
Chronic kidney disease
Decrease in renal function/GFR usually as a result of chronic or destructive renal disease
Causes – DIABETIC NEPHROPATHY, HYPERTENSIVE NEPHROSCLOEROPATHY, polycystic kidney disease, glomerulonephritis
Treatment – may need to adjust renally-excreted drugs, review med list for offending agents, prevent progression, dialysis treatment depending on stage
Staging of CKD
Stage 1 – GFR > 90
Stage 2 – GFR 60-89
Stage 3 – GFR 30-59, start prepping for dialysis
Stage 4 – GFR 15-29
Stage 5 – GFR < 15, kidney failure requiring dialysis or transplant
Contrast-associated nephropathy
Risk factors – renal insufficiency, DM, age, contrast volume
Prophylactic strategies – use contrast only when necessary, peri-procedural volume administration is mainstay in prevention
Treatment – maintain hemodynamic status to ensure renal perfusion, diuretics may be needed for fluid removal (doesn’t actually treat)
Hyponatremia (basic)
o Normal Na: 135-145
o Most common electrolyte disturbance in acute care
o 3 types – isotonic, hypertonic, and hypotonic
o Workup – obtain serum Na (normal: 10-20), obtain serum osmo (normal: 270-290)
Isotonic hyponatremia
o “Normal serum”, serum osmo 270-290
o Typically r/t a chronic process where Na is chronically displaced by an in-dissolvable solute (HLD is most common cause)
o No additional workup is required
o No risk of fluid shifts or neuro complications
o Treatment – Na replacement isn’t necessary, correct the in-dissolvable solute level
Hypertonic hyponatremia
o “Thick serum”, serum osmo > 290
o Typically r/t acute increase in another dissolvable solute which causes kidneys to dump Na
o No additional workup is required
o There is a risk of fluid shift from intracellular to intravascular space resulting in cellular shrinkage (cells’ attempt to dilute the serum) which can pose a risk for neuro complications
o Treatment – Na replacement is typically not acutely necessary, correct the underlying cause (remove excess dissolvable solute)
Hypotonic hyponatremia
o “Thin serum”, serum osmo < 270
o Typically r/t volume overload or volume depletion
o Additional diagnostic workup – assess patient’s volume status, obtain a urine Na (normal: 10-20)
o 3 types – hypervolemic hypotonic hyponatremia, hypovolemic hypotonic hyponatremia, euvolemic hypotonic hyponatremia
Hypervolemic hypotonic hyponatremia
o Diagnostic – serum Na < 135, serum osmo < 270, signs of fluid overload
o Cause – patient is retaining free water, most commonly caused by cardiac, hepatic, or renal failure
o Risk of fluid shift from intravascular to intracellular space resulting in cellular swelling which could result in neuro complications
o Treatment – treat underlying disease process, free water restriction, consider diuresis
Hypovolemic hypotonic hyponatremia
o Diagnostics – serum Na < 135, serum osmo < 270; urine Na > 20 = renal losses but urine Na < 10 = extra-renal losses; signs of fluid depletion
o Cause – patient is losing water and Na at equal rate; most common renal cause is excessive diuresis; most common extra-renal cause is third-spacing, GI loss, and/or excessive sweating
o Risk of fluid shift from intravascular to intracellular space resulting in cellular swelling which could result in neuro complications
o Treatment – volume replacement with NS at slow rate, once volume status is restored the stimulus for ADH is removed
Euvolemic hypotonic hyponatremia
o Additional diagnostic work up – obtain urine osmo
o If urine osmo > 100, consider SIADH, hypothyroidism (most common), or glucocorticoid deficiency
o If urine osmo < 100, consider 1st degree polydipsia
General principles for Na replacement
o For asymptomatic or chronically symptomatic patients – correct Na at rate of ≤ 0.5 mEq/L/hr
o For acutely symptomatic patients – correction is faster (2 mEq/L for the first 2-3 hours)
o In general, the rate of Na increase should not be > 6 mEq/L/day (chronic) or 8 mEq/L/day (acute) to avoid central pontine or osmotic demyelination
Hypernatremia (everything except tx)
o Typically r/t loss of water and/or decreased access to free water
o Urine osmo is needed for accurate assessment and dx
o Normal random urine osmo is 300-900
o If urine osmo < 700-800, points towards renal losses; renal losses include DI or diuresis
o If urine osmo > 700-800, points to non-renal causes; non-renal losses include GI water loss or Na overload
Hypernatremia treatment
o Calculate free water deficit and replace with D5W, 0.45%NS, or free water via gastric tube
o Do not decrease Na by more than 0.5 mg/L/hr to avoid cerebral edema
o Check Na levels every 1-2 hours
o Treat DI with DDAVP or Na restriction
o Treat Na overload with D5W and diuresis
Hypokalemia (everything except treatment)
o Typically results from K losses via GI tract, renal system, or transcellular shifts
o Common symptoms – CARDIAC RHYTHM DISTURBANCES (increased QT interval, v. fib, ventricular ectopy), n/v, muscle cramps
o A urine K can help identify the cause of the loss with a 24-hour urine study
o Urine K < 25 – GI losses or transcellular shift
o Urine K > 30 – renal losses
Hypokalemia treatment
o Treatment is more aggressive if cardiac rhythm disturbances are present
o Replace K (KCl) – 10 mEq of KCl will raise serum K by ~ 0.1
o Example of non-urgent treatment: 40 mEq PO q4-6h
o Example of urgent treatment: 10 mEq/hour IV
o Check Mg levels – if Mg < 1.2, need to replace Mg with Mg Sulfate 1-2g IV; need a normal Mg to be able to “hold on” to the K replacement
Hyperkalemia (everything except tx)
o Typically results from K retention from renal failure and transcellular shifts
o Common symptoms – CARDIAC RHYTHM DISTURBANCES (peaked T-waves, increase PR interval, increase QRS, asystole, V-fib.), weakness, paresthesia, palpitations
o Rule out causes of pseudo-hyperkalemia
Hyperkalemia treatment
o Treatment is more aggressive if cardiac rhythm disturbances are present
o Ca gluconate 1-2 amps IV (onset < 3 minutes) – useful in dialysis patients, stabilizes cell membrane
o 10 units regular insulin IV + 1-2 amps D50 IV (15-30 minutes)
o Lasix ≥ 40 mg IV (30 minutes)
o Dialysis
Hypocalcemia (everything except treatment)
o Ca < 8.5
o Typically results from a secondary process including hypoparathyroidism, chronic renal failure, vitamin D deficiency
o Common symptoms – NEUROMUSCULAR IRRITABILITY, increased DTRs, seizures, cramping, irritability
o Chvostek’s sign – tapping on cheek/face causes facial twitch
o Trousseau’s sign – place BP cuff on arm and inflate 20 mmHg above SBP, causes carpal spasm
o Ca is protein-bound so may have to get an ionized Ca
Hypocalcemia treatment
o Symptomatic – Ca gluconate IV 1-2g over 20 minutes + calcitriol
o Asymptomatic/chronic – oral Ca 1-3 g/day via Ca citrate + vitamin D PO weekly x8-10 weeks
o Chronic renal failure – phosphate binders + oral calcium
Hypercalcemia (everything except treatment)
o Ca > 10.5
o Typically results from a secondary process including MALIGNANCY (> 90%) or hyperparathyroidism
o Common symptoms – asymptomatic or vague symptoms, mental status change, abdominal pain, fatigue, n/v, weakness
o Serum Ca > 13-15 is considered a medical emergency (hypercalcemic crisis)
Hypercalcemia treatment
o NS 4-6 L/day and consider adding Lasix if patient is volume overloaded (onset within an hour)
o Bisphosphonates (onset 1-2 days), found to be useful in malignancy
o Dialysis for emergency situations
UTI
- Common symptom complex – dysuria, urgency, and frequency
- Uncomplicated UTI – no CVA tenderness, fever, nausea, or vomiting
- Complicated UTI or pyelonephritis – + CVA tenderness, fever, nausea, and/or vomiting
- Uncomplicated UTI treatment – UA with culture; TMP-SMX (Bactrim) 1 tab PO twice daily x3 days or Nitrofurantoin (Macrobid) 100 mg PO twice daily for 5 days (if sulfa allergy)
- Complicated UTI or pyelonephritis treatment – Cipro 500 mg PO twice daily or 1000 mg once daily or Levaquin 750 mg PO daily for 5-7 days
- Reevaluation – if patient doesn’t respond to initial tx, continue therapy for a 2 week course; if still not working, admit to hospital and order IV antibiotics or continue PO regimen for 4-6 weeks
CAUTI management
- UA with culture and blood cultures
- Relieve catheter and evaluate for obstruction
- Ampicillin + Gentamicin OR Zosyn 3.375g IVq6h (duration varies)
- If patient also has pyelonephritis, use Cipro or levofloxacin [Levaquin]
Chlamydia
- Pathogen – chlamydia trachomatis
- Women presentation – most have no symptoms; lower abdominal pain, discharge, dysuria
- Men presentation – 50% have no symptoms; cloudy thick penile discharge, unilateral testicular pain/swelling
- Diagnostics – NAAT test
- Treatment – azithromycin 1g PO once
Gonorrhea
- Pathogen – N. gonorrhoeae
- Female presentation – 80% asymptomatic; dysuria, labial pain/swelling, discharge
- Male presentation – more symptomatic than women; profuse purulent yellow/green discharge, dysuria
- Diagnostics – NAAT test
- Treatment – ceftriaxone 250 mg IM once + azithromycin 1g PO once
Trichomoniasis
- Pathogen – trichomonas vaginalis
- Presentation – frothy, gray, or yellow/green discharge; strawberry cervix (petechiae on cervix)
- Diagnostics – NAAT swab
- Treatment – Flagyl 2g PO once
