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. Structural abnormalities include albuminuria of more than 30 mg/day, presence of hematuria or red cell casts in urine sediment, electrolyte and other abnormalities due to tubular disorders, abnormalities detected by histology, structural abnormalities detected by imaging, or history of kidney transplant.

• 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).
• CKD stage 5, previously referred to as end-stage renal disease (ESRD), occurs when the GFR falls below 15 mL/min/1.73 m2 (or in patients receiving renal replacement therapy (RRT.
• Prognosis depends on cause of kidney disease, GFR at time of diagnosis, degree of albuminuria, and presence of other comorbid conditions.

CLINICAL PRESENTATION

CKD development and progression are insidious. Patients with stage 1 or 2 CKD usually do not have symptoms or metabolic derangements seen with stages 3 to 5, such as anemia, secondary hyperparathyroidism, cardiovascular disease (CVD), malnutrition, and fluid and electrolyte abnormalities that are more common as kidney function deteriorates.

• Uremic symptoms (fatigue, weakness, shortness of breath, mental confusion, nausea, vomiting, bleeding, and anorexia) are generally absent in stages 1 and 2, minimal during stages 3 and 4, and common in patients with stage 5 CKD who may also experience itching, cold intolerance, weight gain, and peripheral neuropathies.
• Signs and symptoms of uremia are foundational to the decision to implement RRT.

Treatment

Goal of Treatment: The goal is to delay the progression of CKD, minimizing the development or severity of complications.

• Use the most current consensus guidelines and the best clinical practices for management of CKD.

Nonpharmacologic Therapy

• Restrict protein to 0.8 g/kg/day if GFR is less than 30 mL/min/1.73 m2.
• Encourage smoking cessation to slow progression of CKD and reduce the risk of CVD.
• Encourage exercise at least 30 minutes five times per week and achievement of a body mass index (BMI) of 20 to 25 kg/m2 .

Pharmacologic Therapy Diabetes and Hypertension with CKD

• Progression of CKD can be limited by optimal control of hyperglycemia and hypertension.
• For more information on diabetes, see Chap. 19.
• Adequate blood pressure (BP) control can reduce the rate of decline in GFR and albuminuria in patients without diabetes. KDIGO guidelines recommend a target blood pressure of 140/90 mm Hg or less if urine albumin excretion or equivalent is less than 30 mg/24 h.
• If urine albumin excretion is greater than 30 mg/24 h or equivalent, the target blood pressure is 130/80 mm Hg or less and initiate first-line therapy with an angiotensin converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB). Add a thiazide diuretic in combination with an ARB if additional reduction in proteinuria is needed. Nondihydropyridine calcium channel blockers are generally used as second-line antiproteinuric drugs when ACEIs or ARBs are contraindicated or not tolerated.
• ACEI clearance is reduced in CKD; therefore, treatment should begin with the lowest possible dose followed by gradual titration to achieve target BP and, secondarily, to minimize proteinuria. No individual ACEI is superior to another.
• For more information on hypertension.

Anemia of CKD

• KDIGO definition of anemia: Hemoglobin (Hb) less than 13 g/dL (130 g/L; 8.07 mmol/L) for adult males and less than 12 g/dL (120 g/L; 7.45 mmol/L) for adult females.