Urology/Nephrology

Question 1

UTI

Answer 1

• MC infxn in older adults
• It is FALSE that only a positive UA and cx are required for dx - need tto correlate these WITH SIGNS AND SXS for dx!
• Bacteriuria and UTI are common in older adults because: urinary stasis, outflow obstruction, shifts in perineal flora (estrogen def), fnal difficulties toileting
• Risk factors
  
  • Women: sexual intercourse, use of spermicidal (esp with a diaphragm)
    
    • Pregnancy: progesterone & estrogen à ureter dilation, inhibition bladder peristalsis
    • Postmenopausal: decreased bladder tone, estrogen deficiency alters normal vaginal flora
  • Males rare for males to have UTI (males should receive workup to r/o GU abnormalities).
    
    • >50y (BPH, Prostate cancer) increased risk with insertive anal intercourse, uncircumcised.
• Etiologies
  
  • E. coli MC organism in complicated/uncomplicated cases
  • Gram negative uropathogens: (Proteus, Enterobacter, Klebsiella, Pseudomonas). Usually ascending infection.
  • Staph. Saprophyticus: esp among sexually active women
  • Enterococci with indwelling catheters
• Clinical Manifestations
  
  • Acute cystitis: dysuria (burning), inc frequency, urgency, hematuria, suprapubic discomfort
  • Pyelonephritis = fever & tachycardia, back/flank pain, (+) CVAT, n/v

Question 2

Urinary Incontinence

Answer 2

• Involuntary loss of urine
• NOT a normal part of aging
• Falls often are the result of an overactive bladder, which may cause the individual to rush to the bathroom
• Meds used for urge pattern incontinence are anticholinergic and are of limited use in the elderly
• Stress, Urge, Overflow

Question 3

Erectile Dysfunction

Answer 3

• Consistent inability to generate or maintain an erection.
• Pathophysiology
  
  • Neurologic (ex DM), psychogenic, vascular (atherosclerotic dz), endocrine d/o (ex prolactinoma), trauma, surgery, medications: ex beta blockers, hydrochlorothiazide, calcium channel blockers.
  • Abrupt onset most likely psychological, gradual worsening indicates systemic causes
• Diagnosis
  
  • H&P exam, testosterone level, other hormone testing.
  • Nocturnal penile tumescence used to evaluate sleep erections.
  • Duplex US to evaluate penile blood flow
• Management
  
  • Phosphodiesterase-5 inhibitor: Sildenafil (Viagra), Tadalafil (Cialis), Vardenafil (Levitra)
  • Testosterone: hormone replacement if testosterone is low
  • Intracavernosum iniection therapy: Prostaglandin E1(alprostadil) or combination of papaverine & phentolamine (causes vasodilation)
  • Vacuum pumps, penile revascularization, penile prosthesis

Question 4

BPH

Answer 4

• Prostate hyperplasia (periurethral/transitional zone) à bladder outlet obstruction. Common in older men (discrete nodules in periurethral zone).
• Hyperplasia is part of normal aging process and is hormonally dependent on the increase of dihydrotestosterone production (& increase of estrogen production)
• Clinical manifestations
  
  • Frequency, urgency, nocturia, hesitancy, weak/intermittent stream force, incomplete emptying and incontinence (extrinsic compression of prostatic urethra)
• Diagnosis
  
  • Digital Rectal Exam (DRE): uniformly enlarged, firm, rubbery prostate; if hard nodular à cancer
  • Urinalysis (UA): should be normal (used to r/o other conditions)
  • Increased Prostate Specific Antigen (PSA) is correlated with risk of sx progression. Normal <4ng/mL
  • Urine cytology: if increase risk of bladder Ca (h/o tobacco use, irritative bladder sx or hematuria)
• Management
  
  • Observation: mild symptoms (monitored annually). Avoid antihistamines & anticholinergics b/c they increase urinary retention
  • 5-alpha reductase inhibitors: Finasteride (Proscar) & Dutasteride (Avodart)
    
    • S/E: sexual or ejaculatory dysfunction, decreased libido, breast tenderness/enlargement
  • Alpha-1 blockers: Tamsulosin most uroselective (Flomax), Alfuzosin (Uroxatral) Doxazosin (Cardura), Terazosin (Hytrin). Provides rapid sx relielf but no effect on BPH clinical course
    
    • S/E: nonselective associated with dizziness & orthostatic BP (due to alpha-1b blockage), retrograde ejaculation.
  • Surgical: Trans Urethral Resection of Prostate (TURP) - removes excess prostate tissue to relieve obstruction
    
    • S/E of TURP: sexual dysfunction, urinary incontinence; or Laser prostatectomy.

Question 5

Prostate Cancer

Answer 5

• Slow growing tumor usually (most pts die with prostate cancer than from it)
• Risk Factors: Genetics; Diet: high fat intake, obesity, African Americans. Adenocarcinoma >95%
• Clinical Manifestations
  
  • Often asymptomatic until invasion of bladder, urethral obstruction or bone involvement.
    
    • Urethral obstruction: increased urinary frequency, urgency, decreased urinary stream, urinary retention.
  • Back pain/bone pain: prostate Ca associated with increased incidence of METS to bone, weight loss.
• Diagnosis
  
  • Screening via DRE & PSA done if >50yo; African-Americans or Fhx >40yo
  • PSA: PSA >70ng/mL increased likelihood for prostate cancer & METS
  • DRE: hard, nodular, enlarged asymmetrical prostate
  • Ultrasound with needle biopsy: if PSA > 4ng/mL. lf >10 à bone scan to r/o METS. Gleason grading
• Management
  
  • Local dz: Radical prostatectomy +/- active surveillance if low grade. S/E: incontinence & impotence
  • Advance dz: External beam radiation therapy, Androgen deprivation (orchiectomy + GnRH agonists). If Bone pain/METS à localized XRT, cryotherapy

Question 6

Renal Failure

Answer 6

• Increased serum creatinine >50% or increased Blood Urea Nitrogen/BUN (azotemia)
• AKI results in retention of urea & other nitrogenous waste products as well as dysregulation of extracellular fluid volume & electrolytes.
• RIFLE Criteria:
  
  • 3 progressive levels of AKI: Risk, lnjury, Failure with 2 outcome determinants: Loss & End stage renal disease
• Phases of AKI: oliguric (maintenance) phase (urine output <400m1/d azotemia, hyperkalemia, metabolic acidosis à diuretic phase (urine output, hypotension, hypokalemia) à recovery.
• 3 Types
  
  • PRErenal, POSTrenal (BOTH rapidly reversible) or INTRATenaI (intrinsic)

Question 7

Dehydration

Answer 7

• Water homeostasis
• The kidney adjusts water balance via ADH. ADH the primary regulator of H₂O excretion
• ADH conserves water by making concentrated urine
• 4 mechanisms for H₂O homeostasis:
  
  • ADH
    
    • Increase of ADH is stimulated by: Hyperosmolarity: most sensitive (increase serum [Na]) = dehydration = decreased free water à ADH increases (increasing free H₂O conservation) lowering osmolarity towards normal.
  • Thirst
    
    • Hypothalamus is the primary regulator of H₂O intake. Hypothalamus thirst center stimulated by:
      
      • Dehydration = increase in serum [Na] = increase serum osmolarity = decreased free water, Thirst center stimulated by these conditions to increase free water intake (rehydration).
      • Hypersomolarity: Osmoreceptors sense increase in serum osmolarity & stimulates thirst to increase free H₂O intake (the increased free water intake reduces serum osmolarity towards normal).
  • Aldosterone
    
    • By holding onto Na, you hold onto H₂O. Aldosterone is important for H₂O retention in regards to intravascular volume (Na + water) not for free H₂O regulation (free H₂O is regulated by ADH). Volume = sodium AND water together.
  • Sympathetic system
    
    • Alpha-1 activation causes arteriole constriction (including the afferent arteriole of the nephron). Afferent arteriole constriction decreases renal perfusion (decreases GFR). A decreased GFR leads to less urine formation (less water leaves the body à H₂O conservation).

Question 8

Dx of UTI

Answer 8

• Urinalysis
  
  • Pyuria: >5 WBC/hpf (esp >10), (+) leukocyte esterase; If WBC casts à pyelonephritis
  • (+) nitrites, hematuria, +/- cloudy urine, inc pH with Proteus, bacteriuria
• Dipstick: (+) leukocyte esterase, nitrites, hematuria. Cystitis associated with WBC’s but not WBC casts.
• Urine Culture: definitive dx. Usually not necessary à ordered in: complicated UTI, infants/children, elderly, males, urologic abnormalities, refractory to tx, catheterized pts).

Question 9

Managment of UTI

Answer 9

• Increase fluid intake, void after intercourse. Phenazopyridine (Pyridium) bladder analgesic (turns urine orange) à Not used >48h due to increased S/E: methemoglobinuria, hemolytic anemia.
• Uncomplicated cystitis
  
  • Fluoroquinolones tx of choice; ex. Ciprofloxacin 25Omg BID x 3d.
  • Trimethoprim-sulfamethoxazole; Double Strength (Bactrim-DS) BID x3d (increased resistance)
  • Nitrofurantoin (Macrobid) 100 BID x 7d; Cefpodixime; Fosfomycin. Post coital à single dose
• Complicated cystitis
  
  • Complicated = underlying condition with risk of therapeutic failure; ex: DM, sx >7d before seeking care, immunosuppression, indwelling catheter, anatomic abnormality, elderly etc.
  • Fluoroquinolone PO or IV, Aminoglycosides x 7-10 (or 14) days
• Pyelonephritis
  
  • Fluoroquinolone PO or IV, Aminoglycoside x 14d (7d may be used in healthy, young female)

Question 10

Stress Incontinence

Answer 10

• D/t increased intraabdominal pressure; rare in men
• Laxity of the pelvic floor muscles
• Clinical manifestations
  
  • Increased intraabdominal pressure from sneezing, coughing, laughing - urine leakage
  • Worse when upright
• Management
  
  • Pelvic floor exercises - Kegel
  • Alpha agonists - Midodrine, Pseudoephedrine

Question 11

Urge Incontinence

Answer 11

• Urine leakage accompanied by or preceded by urge
• Detrusor muscle overactivity = overactive bladder
• Clinical manifestations
  
  • Urgency, frequency, small volume voids, nocturia
• Management
  
  • Bladder training
  • Anticholinergics = 1st line meds in urge
    
    • Oxybutynin, Tolterodine
  • TCAs
  • Mirabegron – Beta 3 agonist

Question 12

Overflow Incontinence

Answer 12

• Urinary retention (incomplete bladder emptying)
• Decreased detrusor muscle activity = underactive bladder
• Bladder outlet obstruction: BPH
• Clinical manifestations
  
  • Small volume voids, frequency, dribbling
  • Increased post void residual >200 mL
• Management
  
  • Intermittent or indwelling cath = 1st line tx
  • Cholinergics = Bethanacol
  • BPH
    
    • Alpha blockers = Tamsulosin