Chapter 1: Introduction & Approach to the Patient

Urine Nephrology Now: A Primer for Students in Nephrology

Andrew Bland, MD

Welcome to Nephrology

Nephrology represents one of the most intellectually challenging and rewarding medical specialties. The kidneys serve as master regulators of homeostasis, integrating cardiovascular, endocrine, metabolic, and inflammatory systems. Understanding kidney function provides insight into how the entire body maintains physiological balance.

Nephrology stands apart from other medical specialties because the kidneys serve as the body's master regulators. Every system you have studied—cardiovascular, endocrine, hematologic, and metabolic—intersects with kidney function. When you understand how the kidneys work, you gain insight into how the entire body maintains homeostasis.

Core Functions of the Kidney

  • Excretory Function: Elimination of nitrogenous wastes (urea, creatinine), clearance of drugs and toxins, regulation of fluid balance.
  • Regulatory Function: Electrolyte homeostasis (Na+, K+, Ca2+, PO43−, Mg2+), acid-base balance maintenance, blood pressure regulation via RAAS.
  • Endocrine Function: Erythropoietin production (RBC stimulation), vitamin D activation (1,25-dihydroxyvitamin D), renin secretion (BP and volume regulation).

Approach to the Nephrology Patient

History Taking Priorities

Successful nephrology consultation begins with focused history taking that addresses kidney-specific concerns while maintaining awareness of systemic disease manifestations. Key areas include fluid intake and urine output patterns, which provide crucial insights into kidney function and volume regulation. Document detailed medication histories, particularly NSAIDs, ACE inhibitors, and diuretics, as these commonly affect kidney function. Family history of kidney disease may suggest genetic conditions like polycystic kidney disease or Alport syndrome. Assess systemic symptoms including edema, dyspnea, fatigue, and previous episodes of kidney stones or infections.

Physical Examination Focus

Volume status assessment represents the cornerstone of nephrology physical examination. Evaluate jugular venous distension, peripheral edema, and orthostatic vital signs systematically. Blood pressure measurement in both arms helps identify renal artery stenosis. Skin examination may reveal uremic frost in advanced kidney failure, bruising suggesting uremic bleeding, or rashes associated with systemic diseases. Cardiac examination should assess for pericardial rubs or murmurs, while abdominal examination may reveal masses or bruits.