GU/Renal Flashcards
Rhabdomyolysis Overview
S/Sx
- acute onset of muscle pain (not r/t physical exertion)
- muscle weakness
- dark urine (myoglobinuria) d/t myoglobins released from damaged muscle → reddish-brown or tea-colored urine; damages kidney → AKF (common complication of rhabdo)
- muscle tenderness & swelling may be seen → r/o compartment syndrome
Labs
- Serum creatine kinase markedly ↑ (5x normal)
- Blood chemistry abnormalities
- ↑ aldolase, LDH
- electrolyte abnormalities
- DIC possible complication
Ask pt if hx of severe exercise, crush injury, high fever, or high-dose statin use
REFER TO ED!
Acute Pyelonephritis Overview
S/Sx
- acute onset of high fever
- chills,
- N/V
- dysuria
- frequent urination
- unilateral flank pain described as “deep ache”
- hx of URI
Indications for hospitalization:
- inability to maintain oral hydration
- persistently high fever >101º/38.4º
- toxic appearance
- immune compromise
- suspicion of sepsis
- noncompliance to treatment
Acute Kidney Injury (Acute Renal Failure) Overview
S/Sx
- abrupt onset of oliguria
- edema
- weight gain (fluid retention)
- lethargy
- nausea
- loss of appetite
characterized by rapid ↓ in renal function and ↑ serum creatinine
During early stages, serum creatinine and eGFR may not accurately reflect true renal function
Most causes of AKI; acute decline of GFR are usually reversible when offending substance is stopped
Most common causes:
- drug-induced AKI (e.g., aminoglycosides, contrast agents, NSAIDs, ACEi, and protease inhibitors)
** Serum potassium should be monitored upon initiation of ACEi or ARB if pt has kidney disease; potassium levels may initially rise and then tape off in 2-3 months; continued monitoring of serum potassium is recommended
Bladder Cancer Overview
S/Sx
- elderly male (median age at dx: 73 years) who smokes w/ painless hematuria (can be microscopy or gross [pink- to reddish-color urine])
- some pts only notice problem after see blood-tinged stain on underwear (males, menopausal females)
- hematuria may only appear at end of voiding
may have irritative voiding sx, NOT related to UTI:
* dysuria
* frequent urination
* nocturia
Dx:
- Order UA, urine C&S, and urine cytology
Those w/ advanced disease may c/o lower abdominal or pelvic pain, perineal pain, low-back pain, or bone pain
Normal Findings: Kidneys
1. Location
2. Function
- Located on retroperitoneal area
- R kidney is lower than L kidney d/t liver displacement
- Basic functional units of kidney: nephrons which contain glomeruli - regulates body’s electrolytes and fluids (affects BP)
- water is reabsorbed back into body by action of antidiuretic hormone and aldosterone
- kidneys excrete water-soluble waste products of metabolism (e.g., creatinine, urea, uric acid) into urine
- secrete several hormones (e.g., erythropoietin-RBC production, renin, and bradykinin-BP, prostaglandins-renal perfusion, and calcitriol/vitamin D3-bone)
- average daily urine output is 1,500 mL
- regulates body’s electrolytes and fluids (affects BP)
Oliguria
urinary output of <400 mL/day (adults)
Lab testing: Serum Creatinine, M vs F
end product of creatinine metabolism, which comes mostly from muscle
- may be falsely ↓ in people w/ low muscle volume (older adults)
** Elevated values seen in pts w/ kidney damage/failure ,use of nephrotoxic drugs, etc
M: 0.7-1.3 mg/dL
F: 0.6-1.1 mg/dL
Factors affecting serum creatinine:
- gender (M > F)
- race (African Americans have more muscle mass)
- muscle mass
When renal function ↓, creatinine level will ↑
** Serum creatinine is a better measure of renal function than BUN or BUN:Cr ratio; but eGFR** is considered the best measure of renal function in primary care
Lab Testing: Estimated Glomerular Filtration Rate
Normal: eGFR >90 mL/min
CKD: eGFR <60 mL/min for at least 3+ months
*Best test to measure kidney function; used to determine chronic kidney ds stages
Calculated by using serum creatinine, age, and gender (with adjustment for those of African American descent)
Estimation Equations, used to calculate eGFR:
- Modification of Diet in Renal Disease (MDRD)
- Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)
- Cockcroft-Fault equation
GFR: amount of fluid filtered by the glomerulus within a certain unit of time; the more damaged the kidneys, the ↓ the eGFR; affected by age (↓ w/ age), sex (M have more muscle mass), and body size
- African Americans’ eGFR values are higher than other races
- Some pts w/ underlying kidney ds may have a normal eGFR
- eGFR is LESS reliable in these cases: pregnancy, muscle wasting, elderly, and LE amputees
Chronic Kidney Disease Stages
1. Stage 1
2. Stage 2
3. Stage 3a
4. Stage 3b
5. Stage 4
6. Stage 5
- > 90 mL/min → Kidney damage w/ normal kidney fx
- 89-60 mL/min → Mild loss of kidney fx
- 59-45 mL/min → Mild-to-mod loss of kidney fx
- 44-30 mL/min → Mod-to-severe loss of kidney fx
- 29-15 mL/min → Severe loss of kidney fx
- <15 mL/min → Kidney failure
Blood Urea Nitrogen (BUN)
- Definition
- What does an elevated BUN mean?
- Causes of elevated BUN? Low BUN?
- Mortality?
- Which lab should you check if abnormal BUN level?
- Liver breaks down amino acids into ammonia → converts it into urea
- BUN = measure of kidneys’ ability to excrete urea (waste product of protein metabolism)
If kidneys are damaged or renal blood flow is ↓, urea level ↑
- NOT as sensitive as serum creatinine or eGFr
High BUN may be caused by:
- acute kidney failure (lowers GFR)
- high-protein diet
- hemolysis
- CHF
- drugs
- Among HF, lower GFR w/ higher BUN = higher mortality; in ICU, ↑ BUN is independently associated w/ higher mortality
Low BUN causes:
- liver damage/disease
- If abnormal BUN level, check eGFR. If eGFR is normal, renal fx is normal
BUN-to-Creatinine Ratio
- ↓ in blood flow of kidneys will ↑ BUN:Cr ration
- used to help evaluate dehydration, hypovolemia, and AKF
- useful for classifying type of failure (renal, infrarenal, or postrenal)
Urinalysis (with Microscopic Exam)
- 3 components of a complete UA
A complete UA consists of 3 components:
- gross evaluation
- dipstick analysis
- microscopic exam of urine sediment
UA: Epithelial Cells
- Large amount of squamous epithelial cells = contamination
- A few epithelial cells = normal
Squamous epithelial cells are associated w/ external urethra and transitional epithelial cells w/ the bladder
UA: Leukocytes
Normal WBC in urine: ≤2-5 WBCs/hpf (high-power field)
- Called leukocyte esterase test w/ urine dipstick strips
- Presence of leukocyte sin urine (pyuria) is ALWAYS abnormal in males →infection
- UA is more sensitive test for infection in males than females
UA: Urine for C&S
≥ 10^5 colony-forming units (CFU)/mL is one dominant bacteria (usually E. coli)
* E. coli = Gram- Enterobacteriaceae
- If multiple bacteria are present = contaminated
- Lower vales = bacteriuria
