L21 - Chronic Kidney Disease (Introduction)

What is the definition of CKD?

Abnormalities of kidney STRUCTURE or FUNCTION present for >3 months with implications for health. CKD can be diagnosed by ≥1 marker of kidney damage (such as ACR ≥30 mg/g) OR GFR <60 mL/min/1.73 m² for >3 months.

What are the major markers of kidney damage used to diagnose CKD?

Albuminuria (ACR ≥30 mg/g), urine sediment abnormalities, electrolyte/other abnormalities from tubular disorders, abnormal histology, structural abnormalities on imaging, or history of kidney transplantation.

Do G1 or G2 alone qualify as CKD?

No. G1 (≥90) or G2 (60–89) requires evidence of kidney damage, such as albuminuria. G3a-G5 (<60) qualify as decreased kidney function when persistent >3 months.

What does CGA staging stand for?

Cause + GFR category + Albuminuria category.

What are the major initiation causes of CKD emphasized by the professor?

Diabetes, hypertension, and autoimmune disease. Diabetes is associated with glomerular disease; HTN is associated with vascular disease.

What is the difference between CKD initiation and progression factors?

Initiation factors cause the initial kidney injury. Progression factors accelerate decline in an ALREADY damaged kidney.

Which conditions can be BOTH CKD initiation and progression factors?

Hypertension, diabetes, and autoimmune disease.

What are the major CKD progression factors?

Persistent HTN, diabetes, or autoimmune disease + proteinuria/albuminuria, smoking, dyslipidemia, obesity, lead exposure, and illicit drug use.

What are all of the CKD GFR categories?

G1 ≥90 = normal/high; G2 60–89 = mildly decreased; G3a 45–59 = mildly-moderately decreased; G3b 30–44 = moderately-severely decreased; G4 15–29 = severely decreased; G5 <15 = kidney failure.

What equation is preferred for staging CKD?

CKD-EPI eGFR. The professor noted that an online calculator is used, so you do NOT need to manually calculate the equation. Cockcroft-Gault estimates CrCl and has historically been used for many drug-labeling studies.

What are the albuminuria categories?

A1: ACR <30 mg/g = normal-mildly increased; A2: 30–300 = moderately increased; A3: >300 = severely increased.

What is the basic pathophysiology of CKD progression?

Loss of nephron mass → remaining nephrons hypertrophy/compensate → glomerular capillary HTN → angiotensin II → proteinuria → irreversible renal parenchymal damage → progressive CKD → ESRD.

What are the 2 major goals of CKD therapy?

1. Delay progression with progression-modifying therapy. 2. Minimize development/severity of CKD complications.

What nonpharmacologic therapies slow CKD progression?

Healthy diet; sodium <2 g/day; more plant-based and fewer ultra-processed foods; 150 min/week moderate-intensity exercise (~30 min × 5 days); smoking cessation.

What are the glycemic and BP goals emphasized for CKD?

HbA1c: individualized, approximately <6.5%-8% in non-dialysis CKD. KDIGO BP: SBP <120 when tolerated using standardized measurement. ACC/AHA BP: <130/80 mmHg.

When should an ACE inhibitor or ARB be used in CKD?

Albuminuria ACR ≥30 mg/g, with or without diabetes. Especially important with HTN + albuminuria.

Why are ACE inhibitors/ARBs nephroprotective in albuminuric CKD?

They ↓ intraglomerular pressure and ↓ proteinuria/albuminuria. Titrate to the highest approved tolerated dose.

What important adverse effects/monitoring should you remember for ACE-I/ARBs?

Can cause hyperkalemia and hypotension; monitor BP, SCr/renal function, K+, and albuminuria.

What are the 4 conceptual pillars of progression-modifying CKD therapy?

RAS inhibitor (ACE-I/ARB), SGLT2 inhibitor, GLP-1 receptor agonist, and MRA. They are a conceptual framework—do NOT automatically start all 4 simultaneously.

When are SGLT2 inhibitors used in CKD?

CKD with eGFR >20 mL/min, WITH or WITHOUT diabetes, to reduce CKD progression and CV events. Examples: canagliflozin, dapagliflozin, empagliflozin.

What happens to an SGLT2 inhibitor if eGFR falls below 20 after treatment has already started?

It may be CONTINUED if tolerated as long as the patient is NOT on RRT (dialysis/transplant).

What are the criteria for considering finerenone (Kerendia)?

T2DM + CKD + eGFR >25 + K+ <5 mEq/L + albuminuria >30 mg/g despite maximum tolerated ACE-I/ARB therapy.

What should you remember about finerenone?

It is a nonsteroidal MRA used in T2DM + CKD. Major ADE = hyperkalemia; also hypotension. Do NOT use if K+ is already ≥5 mEq/L. Contraindications listed include strong CYP3A4 inhibitors and adrenal insufficiency.

When are GLP-1 receptor agonists used in T2DM + CKD?

When additional glycemic and cardiovascular benefit is needed. Semaglutide (Ozempic) was specifically noted to reduce CKD progression, kidney failure, and CV death in adults with T2DM + CKD.

How is dyslipidemia managed in CKD?

Follow ACC/AHA guidelines. If a dialysis patient was NOT already taking a statin before dialysis, do NOT routinely initiate one after dialysis begins.

What are the major complications of CKD?

Fluid/electrolyte disorders, metabolic acidosis, metabolic bone disease, anemia, cardiovascular disease, pruritus, malnutrition, and uremic bleeding.

What are the major clinical signs/complications seen in stages 3-5 CKD?

Fluid/electrolyte: hyperkalemia + metabolic acidosis. Endocrine: secondary hyperparathyroidism, ↓ vitamin D activation, gout. Hematologic: anemia of CKD, iron deficiency, bleeding. CV/pulmonary: edema, worsening HTN, arrhythmias.

How do CKD symptoms change by stage?

Stages 1-2 may be asymptomatic; stages 3-4 may have minimal symptoms; stage 5 has more symptoms.

What symptoms can occur in CKD?

Edema, weight gain, SOB, cold intolerance, palpitations, cramping/muscle pain, fatigue, itching, peripheral neuropathy, depression/anxiety, and sexual dysfunction.

What are uremic symptoms?

Fatigue, weakness, nausea/vomiting, loss of appetite, bleeding, and mental confusion.

What important normal lab ranges do I need to KNOW?

Na+ 135–145 mEq/L; K+ 3.5–5.0 mEq/L; CO2/bicarbonate 22–26 mEq/L.

What CKD mineral-related normal ranges are listed in the lecture?

Ca2+ 8.4–10.2 mg/dL; PO4 2.7–4.6 mg/dL. PTH: 10–60 pg/mL for stages 3-4 and 130–600 pg/mL for stage 5. Your notes say these are provided on the exam.

How is anemia defined in CKD according to the lecture?

Hgb <13 g/dL in males or <12 g/dL in females.

What 25-OH vitamin D level indicates vitamin D insufficiency/deficiency?

<30 ng/mL.

What lab patterns should make me recognize common CKD complications?

↑K+ = hyperkalemia; ↓CO2/bicarbonate = metabolic acidosis; ↓Ca2+ + ↑PO4 + ↓vitamin D activation/↑PTH = CKD mineral/bone abnormalities; ↓Hgb = anemia.

What subjective symptoms of CKD does TM have?

Fatigue, nausea, and vomiting.

What objective CKD findings does TM have?

2+ pedal edema; ACR 350 mg/g; elevated BUN/SCr, K+ and phosphate; low Ca2+ and CO2/bicarbonate.

How is TM's CKD staged?

Cause = HTN + diabetes; eGFR 28.3 = G4; ACR 350 mg/g = A3. Therefore: HTN/DM, G4 A3.

What are TM's CKD progression factors?

HTN, T2DM, smoking, dyslipidemia, and albuminuria.

What progression-modifying problems are present in TM?

HTN: BP 146/84, above goal. Diabetes: needs additional CKD-protective therapy. Dyslipidemia: needs FLP/statin assessment. Smoking: needs cessation. Severe albuminuria: ACR 350 mg/g.

What progression-modifying treatment plan was recommended for TM?

After correcting hyperkalemia: lisinopril 5 mg daily for BP/proteinuria; dapagliflozin 10 mg daily for CKD/CV benefit; obtain FLP + baseline LFTs and initiate appropriate statin; smoking cessation/5 A's ± NRT.

Why must TM's hyperkalemia be corrected before starting lisinopril?

His K+ is already 5.5 mEq/L and ACE inhibitors can further increase potassium.

What monitoring was recommended for TM after progression-modifying therapy?

Lisinopril: BP, HR, SCr, K+, urine ACR in ~4 weeks. Dapagliflozin: BG and SCr in ~4 weeks.

How should I approach a CKD case on an exam?

1. Confirm CKD (>3 months). 2. Determine Cause. 3. Use eGFR for G stage. 4. Use ACR for A stage. 5. Identify progression factors. 6. Identify complications from symptoms/labs. 7. Determine appropriate progression-modifying therapy.

How can I quickly remember the CKD GFR cutoffs?

Think 90 → 60 → 45 → 30 → 15: G1 ≥90; G2 60–89; G3a 45–59; G3b 30–44; G4 15–29; G5 <15.

How can I quickly remember the albuminuria cutoffs?

30 and 300: A1 <30; A2 30–300; A3 >300 mg/g.

What treatment thresholds are highest yield for this CKD lecture?

ACE-I/ARB: ACR ≥30. SGLT2i: eGFR >20. Finerenone: T2DM + eGFR >25 + K+ <5 + ACR >30 + max tolerated ACE-I/ARB.