Introduction to nephrology

Nephrology, the subspecialty of internal medicine that covers the diagnosis and treatment of kidney diseases, hypertension, and electrolyte disorders, is often viewed as very difficult to master.

In Clinical Handbook of Nephrology , we break down the field of renal and electrolyte disorders into concise text, tables and algorithms that provide the reader with a simplified yet comprehensive approach to nephrology. While one cannot become a nephrologist in a month, this handbook has been designed to enable the reader to master the major areas of the specialty to a surprising degree of sophistication in the course of a 4-week period. Note that the reader should already have a basic knowledge of renal pathophysiology and function, body fluids, and metabolic disorders. However, a review of Chapter 3 will serve as a helpful memory refresher.

We suggest starting with a brief review of the first four chapters.

Week 1:	Chapter 1, Introduction to Nephrology
	Chapter 2 , Symptoms, Signs, and Differential Diagnosis
	Chapter 3 , Renal Physiology
	Chapter 4 , Water and Electrolyte Disorders

Readers should then review the data in the remaining chapters specified for each week as follows:

Week 2:	Chapter 5 , Acid-Base Disorders
	Chapter 6 , Urinalysis and Diagnostic Tests
	Chapter 7 , Acute Kidney Injury
	Chapter 8 , Glomerular Diseases
Week 3:	Chapter 9 , Various Kidney Diseases: Interstitial, Cystic, Obstructive, and Infectious Diseases
	Chapter 10 , Kidney Disorders in Other Diseases
	Chapter 11 , Chronic Kidney Diseases
	Chapter 12 , Kidney Replacement Therapy: Dialysis
Week 4:	Chapter 13 , Kidney Transplantation
	Chapter 14 , Hypertension
	Chapter 15 , Nephrolithiasis and Nephrocalcinosis
	Chapter 16 , Lab Values for Nephrology

Before we get started, let’s review the patient issues that will be the subject of most nephrology referrals or consultations.

1.1 Common nephrology consultations

Condition	Look For…
• AKI or ARF • Etiology: prerenal, postrenal, intrinsic renal disease	• Cr increase with daily trend • Hx & Px for edema/volume depletion	• UA • Serum electrolytes, calcium phosphate • Urine chemistries (Cr, Na ⁺for fractional excretion, Osm) • Renal US • UO
• CKD or chronic renal failure • Etiology of nephrotic syndrome, nephritis, or systemic diseases involving the kidneys	• Cr increase with weekly or monthly trend • Hx & Px for edema/volume depletion • UA • UO • Renal US	• Anemia • Cholesterol • Albumin • Ca ⁺⁺/phos/bone disorders • Acidosis • PTH
• Evaluation of electrolyte disorders and volume status • Hypo/hypernatremia, hypo/hyperkalemia	• Hx & Px for edema/volume depletion • Cr • UO	• Urine “electrolytes” (U _Na+, U _K+, U _Cl–) • U _Cr, U _Osm
• Calcium, phosphate, and/or magnesium disorders	• Hyper/hypocalcemia • Hyper/hypophosphatemia • Hyper/hypoparathyroidism	• Vitamin D levels • Bone pathology • Dietary intake
• Nephrolithiasis, management and prevention	• Need for urological intervention • Stone composition • Crystalluria	• Blood tests (e.g., Cr, calcium, phosphate, uric acid, HCO ₃) • 24-hour urine chemistries for supersaturation • Urine pH
• Need for HD, PD, CRRT, vascular access, or options counseling in ESKD or ARF patients	• Uremic symptoms • Volume overload/CHF • Uncontrollable hyperkalemia or acidosis • Low Cr clearance • Pericarditis	• Encephalopathy • Uremic coagulopathy
• Hypertension: controlled, uncontrolled, accelerated, or malignant	• Evaluate for secondary causes vs. “essential” causes and for end organ damage	• Management with specific drug indications
• Acid-base disorders	• Arterial or venous pH • Blood HCO ₃ • _pCO ₂	• Anion gap • Serum electrolytes
• Adjustment of medications in renal disease or kidney transplant patients	• Renal vs. hepatic excretion • Cr clearance or eGFR	• Knowledge of immunosuppressive drugs