Being stranded in the middle of a vast ocean is life’s biggest irony of eventual death—being surrounded by water everywhere, but to die due to lack of water.
This happens because our kidney’s concentrating ability is limited. For every liter of ocean water that we drink, an additional 1/2 liter of freshwater is needed to excrete the total salt load consumed. Rodents’ kidneys have more than 2 times the concentrating ability of humans’, hence they can survive on salty sea water.
6.1 Irritative and Voiding Symptoms
Something is irritating the bladder wall or urethra causing inflammation. This results in: | Something in bladder is obstructing the urinary outflow, leading to dribbling of urine, sensation of incomplete voiding, and/or needing to strain to urinate. |
Common causes: Stone, infection and tumor (MRS SIT)a | |
For recent onset of symptoms,NSIDx – UA. | |
Irritative and voiding symptoms are collectively called “lower urinary tract symptoms” and have significant overlap:
Acute prostatitis can present with acute irritative and voiding symptoms.
Tumor in the neck of bladder can present with chronic irritative and voiding symptoms.
Patients with BPH have increased risk of urinary tract infection. In this case, a patient with longstanding hx of voiding symptoms, now presents with acute irritative symptoms due to development of cystitis or prostatitis.
6.2 Urinary Tract Infection and Prostatitis
Urinalysis
In patients presenting with acute irritative symptoms, first SIDx is always urinalysis (UA).
Urinary tract infection (UTI) may also cause hematuria (RBCs ≥ 3/hpf in unspun sample)
6.2.1 Acute Cystitis
Presentation: acute irritative symptoms (+/- voiding symptoms). Older patients can have mild confusion. UA will show significant pyuria.
Asymptomatic Bacteriuria
Definition: Significant colony counts of bacteria in urine culture (i.e., ≥ 105 cfu/mL) but with no irritative bladder symptoms or systemic signs of infection.
Rx: Antibiotics are indicated only in pregnancy or in patients who are undergoing urological procedure likely to have mucosal bleeding.
6.2.2 Acute Complicated UTI (including Pyelonephritis) and Acute Prostatitis
Definition: UTI + signs of extension beyond bladder e.g., fever, chills, rigors, sepsis, costovertebral angle tenderness, flank pain, acute creatinine elevation, altered mental status.
Risk factors for extension: uncontrolled diabetes, immunosuppression, urinary stones, urinary tract abnormalities, presence of indwelling structures (e.g., Foley catheter, urinary stent), pregnancy, etc.
Management
aProstatic massage is contraindicated in suspected acute bacterial prostatitis, but it is ok to do a digital rectal examination to examine prostate.
bAcute elevation of PSA can support the dx of acute prostatitis.
cIn patients > 35 years old AND no hx of high-risk sexual behavior, use trimethoprim-sulfamethoxazole or a fluoroquinolone for a total of 6 weeks.
1 In sexually active patients with prostatitis <35 years of age, or >35 years of age with high risk sexual behavior, MCC are gonorrhea and chlamydia. For these patients, test for STD and initiate empiric treatment that covers these organisms.
dUrethral catheterization is contraindicated in acute bacterial prostatitis as this might lead to dissemination of infection.
eChoose empiric antibiotic therapy as following:
If risk factors for pseudomonas are present (e.g., recent urological instrumentation or neutropenia), use anti-pseudomonal antibiotic (e.g., cefepime, piperacillin-tazobactam).
If urine gram stain reveals gram positive cocci, cover for enterococcus and staphylococcus; can use piperacillin-tazobactam
fIn very sick patients (e.g., ICU or step-down unit), add antibiotics with MRSA and ESBL coverage (e.g., IV vancomycin + meropenem).
gUse oral ciprofloxacin, levofloxacin (5–7 days), trimethoprim-sulfamethoxazole (7–10 days) or B-lactams such as cefpodoxime, cefdinir, amoxicillin-clavulanate (10–14 days).
hCT scan with IV contrast is the best test. When contraindicated (e.g., in pregnancy) do renal ultrasound. Look for pyelonephritis complications such as abscess or emphysematous pyelonephritis.
Risk factors for development of these complications include immunosuppression or DM. Treatment for both is percutaneous or surgical drainage and IV antibiotics. Severe cases may require nephrectomy.
6.2.3 Perinephric/renal Abscess
Source of infection: local infection (e.g., pyelonephritis), or hematogenous spread (e.g., Staph. aureus abscess due to infective endocarditis)
Presentation: history of pyelonephritis with no clinical improvement despite adequate treatment, with persistent flank pain and high-grade fever. Exam may reveal palpable abdominal mass. UA may reveal pyuria, but urine culture may be negative (when abscess is not communicating with urinary system).
Workup: CT scan with IV contrast is the best test. When contraindicated (e.g., in pregnancy), do renal ultrasound.
Rx: IV antibiotics (e.g., Piperacillin-tazobactam) and percutaneous drainage of abscess. Severe cases may require nephrectomy.
6.2.4 Chronic Prostatitis and its Differential Diagnosis
Presentation: chronic or recurrent irritative symptoms in males with or without voiding symptoms.
Workup:
aPatients can also present with recurrent UTIs or recurrent bacteriuria of the same organism. Treatment is similar to acute bacterial prostatitis: use fluoroquinolone (ciprofloxacin or levofloxacin) or trimethoprim-sulfamethoxazole for total of 6 weeks.
bProstate may be mildly tender. Treatment includes a trial of empiric antibiotic therapy (e.g. ciprofloxacin) and alpha-1 blocker (e.g., tamsulosin). In sexually active males, rule out STD prostatitis and consider infection with atypical organism (chlamydia, mycoplasma, etc.). In patients with hematuria, do further urologic workup (including cystoscopy).
cIn patients with chronic irritative bladder symptoms of unknown cause, particularly in patients > 40 years of age, or in patients with persistent hematuria we must rule out urogenital cancer by doing cystoscopy and urine cytology.
Benign Prostatic Hyperplasia
Presentation: Older male patients presenting with chronic voiding symptoms. Patient may also have chronic mild urgency and frequency. Benign prostatic hyperplasia (BPH) alone usually does not cause dysuria.
Exam: Digital rectal examination may reveal firm, smooth enlargement of prostate gland; however, there is a poor correlation between prostate enlargement (by exam or transrectal US) and obstructive symptoms due to BPH. Workup: NSIDx is urinalysis, serum creatinine, and prostate-specific antigen (PSA) to screen for prostate cancer.
Step-wise management
Drug of choice is alpha-1 antagonist which act on smooth muscles. Tamsulosin is preferred, because it has fewer side effects than other drugs in this group. Prazosin and doxazosin (+ azosin) can be considered when patients have coexistent hypertension
If patient continues to have symptoms, NSIM: add a 5-alpha reductase inhibitor (inhibits conversion of testosterone to dihydrotestosterone). They act on the epithelial portion of prostate, and has been shown to reduce prostatic volume. For example, finasteride and dutasteride (+terides)
Transurethral resection of prostate is indicated, if symptoms do not improve significantly with medical management or patients develop complications (e.g., hydronephrosis, renal failure, recurrent infection.)
Prostate Cancer
Background: Most common cancer in males and second Most common cause (MCC) of cancer death in males. There is a familial predisposition.
Risk factors: Black men, family hx of prostate cancer, BRCA mutation, etc.
Screening: Routine screening via PSA is controversial. Informed decision-making process is recommended. Patients who opt to screen for prostate cancer can begin at age 50 years.
Presentation: In most patients, prostate cancer is suspected when found to have high PSA levels or abnormal digital rectal examination. Symptoms, when present, are often due to metastatic disease, such as low back pain/bone pain or pathological fracture (especially around the lumbar vertebra region).
Prostate exam: This may reveal indurated, nodular and/or irregular prostate enlargement.
Best SIDx: Prostate biopsy under transrectal ultrasound guidance.
Management
Surveillance | |
Either prostate tissue ablation with radiation or removal with surgery + androgen depriving therapyd | |
aExternal beam radiation or radioactive pellets implantation into prostate. | |
bMost common side effects of surgery are erectile dysfunction and urinary incontinence. | |
cIn patients with high-risk features, prostate tissue ablation or removal may be offered. | |
dProstate cancer is an androgen-dependent cancer, so decreasing androgen production will shrink the tumor. This can be achieved by either removing both testicles (surgical orchiectomy) or by using medical therapy to decrease androgen production (as shown below). | |
Medical antiandrogen therapy
GnRH agonist: leuprolide, goserelin,a nafarelin, etc. (+ relins) | Mechanism of action: Continuous stimulation by GnRH paradoxically results in downregulation of androgen production |
Bladder Cancer
Risk factors: Phenacetin-containing analgesics, pioglitazone (possible), ethanol, smoking, Schistosoma haematobium (parasitic infection), aniline dyes, arsenic exposure, cyclophosphamide (chemotherapy).
Presentation: Painless gross or microscopic hematuria. Patients may also have chronic or inter-mittent-and-recurrent, irritative, and/or voiding symptoms.
Workup
NSIDx is office-based cystoscopy with biopsy (most appropriate diagnostic step) + urine cytology.
After confirming dx, NSIM is transurethral resection of bladder tumor (requires anesthesia), and CT/MRI scan with IV contrast for staging.
Urinary Tract Stones
Presentation: Depends upon location of stone and complication (stones → obstruction → urine stasis → infection).
Management of Suspected Urinary Tract Stone
If patient is in pain, First SIM is adequate hydration and analgesia (the choice of analgesia is nonsteroidal anti-inflammatory drugs [NSAIDs]).
Opiates are given when NSAIDs fail to control pain or when NSAIDs are contraindicated (e.g., renal failure). Opiates may exacerbate nausea/vomiting, which is common in renal/ureteral colic.
NSIM is UA (best initial test): symptomatic stones usually present with hematuria. Alkaline pH (pH > 7.5) may signal possible infection with urease-producing bacteria (e.g., Proteus, Klebsiella) and possibility of staghorn calculi. Urine pH < 5.5 may suggest uric acid stone.
• NSIDx is CT scan of abdomen and pelvis without IV contrast.
It has high sensitivity and specificity. In pregnant patients, do renal ultrasound, as CT scan is not desirable.
5 Do not use contrast when looking for stones (or hemorrhage). Stones, blood, and contrast have similar high density appearance on CT. Using contrast will muddle the picture. For example, first diagnostic test in suspected stroke is CT scan of head without contrast. On the other hand, when looking for malignancy or infection use IV contrast. For example, first diagnostic test in a patient with fever and a new focal neurological deficit is CT scan of head with contrast.
Hospitalization and urology evaluation is indicated in following situations:
These patients frequently need emergent decompression, such as percutaneous nephrostomy or ureteral stent placement.
Further management of symptomatic urinary tract stone depends upon stone size, type, and location
Always check stone composition after its removal or spontaneous passage, because it determines preventive strategies
Proteus MUSt kill urea. Proteus, Morganella, Ureaplasma, SerraTia, Klebsiella, etc. produce urease (which breaks down urea)
A 25-year-old female presents with urinary frequency, urgency, dysuria, and hesitancy for the last few days. Exam reveals suprapubic pain and mucopurulent discharge out of urethra. She has hx of multiple sexual partners. UA is leukocyte esterase positive but nitrites negative.
A 42-year-old male presents with few weeks hx of urinary frequency, urgency, dysuria, and dribbling of urine. For the last few days he also started noticing painful, tender, and swollen testes. Exam reveals tender testes and prostate.
5. What is the treatment and duration?
6. Patient has bile salt deficiency due to ileitis in Crohn’s disease. What type of urinary stone would you expect?
7. A 67-year-old male has few years hx of intermittent bloody urine, urinary frequency, urgency, dysuria, and dribbling of urine. He has no hx of fevers, chills, but has had significant unintentional weight loss. UA shows multiple RBCs and only few WBCs. What is the likely Dx?
8. A 45-year-old male is diagnosed with severe acute transverse myelitis and neurogenic bladder. What is an effective way to reduce risk of UTI in patients with neurogenic bladder?
A patient has ureteral colic. Urine pH is alkaline (pH> 5.4).
9. What two diagnoses should come to your mind?
10. By looking at basic metabolic profile, would you be able to differentiate in between them? A patient has recurrent calcium oxalate stones with no obvious risk factors.
12. If urinary Ca2+ excretion is high and serum Ca2+ is normal, then what is the likely dx?
13. What adjunctive treatment would you give to prevent stone formation?
14. If both urinary Ca2+ and serum Ca2+ are high, what is the likely Dx?
A 50-year-old male presents with few months hx of bloody urine, urinary frequency, urgency, dysuria, difficulty urination, and dribbling of urine. He has no hx of fevers, chills or weight loss. UA shows multiple RBCs and only few WBCs. Prostate exam is unremarkable.
6.3 Acute Renal Failure/Acute Kidney Injury
General presentation
Best initial test: serum creatinine and blood urea nitrogen (BUN). Creatinine is the most sensitive indicator of renal failure and is used to calculate glomerular filtration rate (GFR). The following properties make creatinine one of the best indicators of renal function:
Management
aIf patient cannot provide good history (e.g., confused patient), first step is to rule out urinary retention by doing a simple bedside test, i.e., bladder scan.
bBladder outlet obstruction is a common reason for acute renal failure in old patients. Causes include urethral stricture, prostate cancer, benign prostatic hypertrophy, cervical cancer, retroperitoneal fibrosis, stone in bladder-neck, atonic bladder, etc.
cFractional excretion of sodium (FENa). In addition to serum sodium and creatinine, we need urine sodium and urine creatinine to calculate this ratio, but no need to remember the formula of FENa as it will be given in exam. A hypoperfused kidney will try to conserve Na by increasing reabsorption of Na+.
7 Caution: Do not rely on FENa when patients are on diuretics or have preexisting tubular disease. In patients on diuresis, use FEUrea instead. Urea is also an osmolyte like Na, but it is not affected by diuretics.
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