3.2 Renal & Genitourinary

Why Renal & Genitourinary Matters on the PANRE

Quick Answer: Renal (~4%) and Genitourinary (~5%) are lower-weight categories individually, but together they carry roughly a tenth of the exam and overlap heavily with cardiovascular, endocrine, and infectious disease content. Recertification questions emphasize categorizing kidney injury, recognizing electrolyte emergencies, and triaging urinary tract and urologic complaints.

The PANRE rewards a systematic approach here: localize the problem (before, in, or after the kidney), recognize when an abnormality is an emergency, and apply the screening and workup rules you use in everyday practice. This section covers acute kidney injury (AKI), chronic kidney disease (CKD), electrolyte and acid-base disturbances, urinary tract infection (UTI) and pyelonephritis, nephrolithiasis, benign prostatic hyperplasia (BPH), and prostate, testicular, and bladder conditions.

Acute Kidney Injury and Chronic Kidney Disease

Acute kidney injury (AKI)

AKI is an abrupt decline in kidney function. The most useful exam framework is the three categories:

Always look for and relieve postrenal obstruction early because it is potentially rapidly reversible, and review the medication list for nephrotoxic agents.

Chronic kidney disease (CKD)

CKD is staged using glomerular filtration rate (GFR) combined with albuminuria, which together estimate progression and cardiovascular risk. Diabetes mellitus and hypertension are the leading causes. Recertification-level management themes:

• Treat the underlying driver — glycemic and blood pressure control.
• Use renin-angiotensin system blockade where indicated for albuminuria, with monitoring.
• Anticipate complications: anemia, mineral and bone disorder, metabolic acidosis, and hyperkalemia.
• Adjust or avoid renally cleared and nephrotoxic drugs and contrast exposure.

Electrolyte and Acid-Base Disturbances

Potassium

Hyperkalemia is the most testable electrolyte emergency. With electrocardiogram (ECG) changes (peaked T waves, widened QRS), management follows a fixed priority:

1. Stabilize the myocardium — calcium (gluconate or chloride) to protect against arrhythmia.
2. Shift potassium intracellularly — insulin with glucose, and a beta-2 agonist as an adjunct.
3. Remove potassium from the body — diuresis, gastrointestinal binders, or dialysis when severe or refractory.

Calcium does not lower the potassium level; it buys time by stabilizing cardiac membranes. Hypokalemia causes weakness and arrhythmia risk and frequently coexists with hypomagnesemia, which must be corrected for potassium repletion to succeed.

Sodium

Approach hyponatremia by volume status (hypovolemic, euvolemic, hypervolemic) and chronicity. Correct serum sodium gradually; overly rapid correction of chronic hyponatremia risks osmotic demyelination. Symptomatic acute hyponatremia is managed more urgently.

Acid-base

Use a stepwise read: identify the primary disorder (acidosis or alkalosis, metabolic or respiratory), then assess compensation, then for metabolic acidosis calculate the anion gap. High-anion-gap metabolic acidosis includes causes such as lactic acidosis, diabetic ketoacidosis, kidney failure, and certain toxic ingestions.

Urinary Tract Infection and Pyelonephritis

The key distinction is lower tract (cystitis) versus upper tract (pyelonephritis) and uncomplicated versus complicated.

Pyelonephritis with obstruction (such as an infected stone) is a urologic emergency requiring decompression. Pregnant patients and those with catheters, immunosuppression, or structural abnormalities are treated as complicated. Asymptomatic bacteriuria is generally not treated except in defined groups such as pregnancy or before certain urologic procedures.

Nephrolithiasis

Kidney stones classically cause acute, severe, colicky flank pain radiating to the groin, often with hematuria and nausea. Non-contrast computed tomography is the standard confirmatory imaging in many settings. Management priorities tested on recertification:

• Analgesia and antiemetics for symptom control, with hydration.
• Stone size and location drive disposition: many small stones pass spontaneously with supportive care and possible medical expulsive therapy.
• Urologic emergencies: obstruction with infection (fever, signs of sepsis) or acute kidney injury from obstruction require urgent urology involvement and decompression.
• Prevention: increased fluid intake and dietary modification tailored to stone composition; calcium oxalate stones are the most common type.

Prostate, Testicular, and Bladder Conditions

Benign prostatic hyperplasia (BPH)

BPH causes lower urinary tract symptoms in older men: hesitancy, weak stream, nocturia, and incomplete emptying. Initial management is symptom-driven, commonly an alpha-blocker for rapid symptom relief and a 5-alpha-reductase inhibitor for larger glands to reduce volume over time. BPH does not cause prostate cancer, but the two can coexist.

Prostate cancer and screening

Prostate cancer is often asymptomatic early. Prostate-specific antigen (PSA) screening is a shared, individualized decision after discussing benefits and harms; it is not a universal mandate. An abnormal digital rectal exam or rising PSA prompts urologic evaluation.

Acute scrotal pain — a do-not-miss emergency

Any acute scrotum is testicular torsion until proven otherwise, and suspicion should not be delayed by imaging if the clinical picture is classic.

Other genitourinary points

A painless testicular mass requires evaluation for testicular cancer (most common solid malignancy in young men). New microscopic or gross hematuria without a clear benign explanation requires evaluation because of bladder and other urologic malignancy risk, particularly in patients with smoking history. Urinary incontinence should be categorized (stress, urge, overflow, mixed) because the type determines treatment.