Chronic Kidney Disease

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CKD Basics - Kidney's Slow Fade

  • Progressive, irreversible decline in kidney function.
  • Diagnostic criteria (must persist ≥3 months):
    • GFR < 60 $mL/min/1.73m^2$
    • OR presence of kidney damage markers.

⭐ CKD is defined by chronicity (≥3 months) of either critically low GFR or evidence of kidney damage (e.g., albuminuria, structural issues).

  • Key Kidney Damage Markers:
    • Albuminuria: ACR ≥ 30 mg/g
    • Urine sediment abnormalities
    • Electrolyte/tubular disorders
    • Structural abnormalities (imaging)
    • History of kidney transplantation
  • Staging (KDIGO): GFR (G1-G5) & Albuminuria (A1-A3) categories. KDIGO CKD Staging by GFR and Albuminuria

CKD Culprits - Usual Suspects

⭐ Diabetes Mellitus (DM) and Hypertension (HTN) are overwhelmingly the two most common causes of CKD worldwide and in India, responsible for over two-thirds of cases.

  • Other Significant Causes:
    • Glomerulonephritis (GN): e.g., IgA nephropathy, FSGS.
    • Polycystic Kidney Disease (ADPKD): Inherited cystic disorder.
    • Chronic Tubulointerstitial Nephritis: From drugs (NSAIDs), infections, reflux.
    • Obstructive Uropathy: Due to BPH, stones, strictures.
    • Autoimmune Diseases: Systemic Lupus Erythematosus (SLE).

CKD Chaos - System Breakdown

  • Key Progression Drivers: Vicious cycle of Glomerular hyperfiltration → Proteinuria → Tubulointerstitial inflammation & fibrosis (TGF-β mediated) → Further nephron loss. Intrarenal RAAS activation amplifies damage.
  • Systemic Complications: 📌 A WET BED
    • Acidosis (Metabolic)
    • Water-Electrolyte Imbalance: ↑$K^+$, ↑$PO_4^{3-}$, ↓$Ca^{2+}$, Fluid overload
    • EPO Failure: Anemia
    • Toxin Accumulation: Uremia (encephalopathy, pericarditis, coagulopathy)
    • Bone Disease (CKD-MBD): ↓Active Vit D, ↑PTH, ↑FGF23. Target PTH 150-300 pg/mL (Stage 5D)
    • Endocrine: Insulin resistance, ↓ T4 to T3 conversion
    • Dyslipidemia: ↑Triglycerides

⭐ Anemia in CKD is primarily due to decreased erythropoietin (EPO) production by the failing kidneys.

CKD-MBD Pathophysiology by GFR

CKD Clues - Spotting Signs

  • Clinical Features:
    • Early: Often asymptomatic.
    • Progressive: Fatigue, edema, HTN.
    • Advanced (Uremia): Nausea, vomiting, pruritus, encephalopathy.
  • Key Investigations:
    • eGFR: Persistent ↓ <60 ml/min/1.73m² for >3 months ($MDRD$/$CKD-EPI$).
    • Albuminuria (Urine ACR): A1 (<30mg/g), A2 (30-300mg/g), A3 (>300mg/g).
    • Renal USG: Small, echogenic kidneys (exceptions: PCKD, diabetic).
    • Labs: Anemia, ↑$K^+$, ↑$PO_4^{3-}$, ↓$Ca^{2+}$. CKD Stages by eGFR

⭐ Urine Albumin-to-Creatinine Ratio (ACR) is a key investigation for detecting and monitoring kidney damage in CKD, and for risk stratification.

CKD Combat - Holding Line

  • Goals: Slow progression, manage complications, RRT prep.
  • Slow Progression:
    • BP: <130/80 mmHg.
    • RAASi: ACEi/ARB (esp. albuminuria).

      ⭐ ACE inhibitors or ARBs are recommended for most patients with CKD, especially those with albuminuria, to slow disease progression and reduce cardiovascular risk.

    • Glucose: HbA1c <7%; SGLT2i.
    • Lifestyle: ↓Protein, ↓Na, ↓K, ↓P; stop smoking.
  • Manage Complications:
    • Anemia: Hb 10-11.5 g/dL (Iron, ESAs).
    • CKD-MBD: ↓PO₄, Vit D.
    • Acidosis: NaHCO₃.
  • RRT Prep:
    • AV fistula (eGFR <20-25 $mL/min/1.73m^2$).

High‑Yield Points - ⚡ Biggest Takeaways

  • CKD: GFR < 60 mL/min/1.73m² for > 3 months or kidney damage.
  • Top causes: Diabetes Mellitus, Hypertension.
  • Complications: Anemia (↓EPO), CKD-MBD (↑PO₄, ↓Ca, ↑PTH), metabolic acidosis, hyperkalemia.
  • ESRD (End-Stage Renal Disease) is GFR < 15 mL/min/1.73m² (Stage G5).
  • Manage by slowing progression, treating anemia (ESAs, iron) & CKD-MBD (phosphate binders, Vit D).
  • Broad waxy casts in urine sediment suggest advanced CKD.

Practice Questions: Chronic Kidney Disease

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A hypertensive diabetic patient with microalbuminuria should receive:

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Flashcards: Chronic Kidney Disease

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Chronic renal failure is most commonly caused by _____, hypertension, and glomerular disease

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Chronic renal failure is most commonly caused by _____, hypertension, and glomerular disease

diabetes mellitus

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