Chapter 74: Chronic Kidney Disease

INTRODUCTION

• Chronic kidney disease (CKD) is defined as abnormalities in kidney structure or function, present for 3 months or longer, with implications for health.

• CKD is classified by cause of kidney disease, glomerular filtration rate (GFR) category, and albuminuria level based on new recommendations from the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, referred to as CGA staging (cause, GFR, albuminuria) (Table 74–1).

• A patient is classified with end-stage renal disease (ESRD) when their GFR is below 15 mL/min/1.73 m² (<0.14 mL/s/m²) and either chronic dialysis or kidney transplantation is needed to sustain life. KDIGO classification will be used in this chapter; the term CKD 5D indicates a patient with ESRD requiring dialysis as either hemodialysis (CKD 5HD) or peritoneal dialysis (CKD 5PD).

• Prognosis of CKD depends on cause of kidney disease, GFR at time of diagnosis, degree of albuminuria, and presence of other comorbid conditions.

PATHOPHYSIOLOGY

• Susceptibility factors increase the risk for kidney disease but do not directly cause kidney damage. They include advanced age, racial or ethnic minority, low income or education, and exposure to certain chemical and environmental conditions.

• Initiation factors directly result in kidney damage and include diabetes mellitus, hypertension, obesity, autoimmune diseases, systemic infections, family history of CKD, reduction in kidney mass, and low birth weight.

• Progression factors are associated with further decline in kidney function after initiation of kidney damage. They include diabetes mellitus, hypertension, proteinuria, obesity, and smoking.

• Most progressive nephropathies share a final common pathway to irreversible renal parenchymal damage and ESRD (Fig. 74–1). Key elements of the pathway to ESRD include loss of nephron mass, glomerular capillary hypertension, and proteinuria.

CLINICAL PRESENTATION

• Progression of CKD from category 1 to 5 occurs over decades in the majority of people who are asymptomatic until they reach CKD 4 or 5. Signs and symptoms seen with stages 4 to 5 include fatigue, weakness, shortness of breath, mental confusion, nausea, vomiting, ...