Chronic Kidney Disease (CKD) | Clinical Medicine

Main ideas / lessons about Chronic Kidney Disease (CKD)

CKD vs Acute Kidney Injury (AKI)

• AKI: abrupt kidney injury with a rapid rise in serum creatinine, typically developing over < 3 months.
• CKD: requires chronicity—a progressive loss of renal function over time.

What defines CKD (functional criteria)

CKD is defined mainly by either:

1. Progressive reduction in GFR (must persist ≥ 3 months).
2. Increased albuminuria/proteinuria (commonly albuminuria).

Albuminuria is emphasized as a strong prognostic marker, especially predicting cardiovascular risk.

Core pathophysiology (common pathway)

• Glomerulosclerosis (with inflammation and fibrosis) progressively damages the kidney’s filtration barrier.
• This leads to:
  • Loss of nephrons → GFR decreases
  • Altered filtration permeability → albumin/protein leaks into urine
• As GFR declines, the kidney’s ability to excrete waste products and regulate electrolytes/acid-base declines → uremic complications.

“Why does glomerulosclerosis happen?” (drivers)

• Mesangial cells secrete extracellular matrix, promoting fibrosis.
• Key stimulators mentioned:
  • Chronic inflammation
  • Ischemia (reduced blood/oxygen delivery)
  • Transient high GFR / hyperfiltration (described as temporary, leading to injury responses)

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Causes discussed (most common etiologies)

Diabetic nephropathy (most common)

• Accounts for about 40–45% of CKD cases (as stated).
• Mechanism described:
  • Persistent hyperglycemia → non-enzymatic glycation → deposition of glycoproteins into the glomerular basement membrane
  • Basement membrane and vascular narrowing → increased intraglomerular pressure
  • Transient hyperfiltration → mesangial activation → extracellular matrix/fibrosis → glomerulosclerosis
• Albuminuria is often an early indicator, sometimes before clear GFR decline.

Hypertensive nephropathy (second most common)

• Accounts for about 30–35% (as stated).
• Mechanism described:
  • Chronic hypertension → afferent arteriolar thickening → narrowed lumen → reduced glomerular blood flow
  • Reduced oxygen delivery → ischemia
  • Ischemia stimulates mesangial cells → extracellular matrix secretion → glomerulosclerosis
• Albuminuria can occur but is typically less pronounced than in diabetic nephropathy.

Glomerulonephritis / chronic glomerular inflammatory disease

• Mentioned as ~10–15% (as stated).
• Examples listed:
  • Membranous nephropathy
  • Membranoproliferative glomerulonephritis
  • Focal segmental glomerulosclerosis
  • (Also referenced nephritic syndromes such as lupus nephritis)
• Mechanism described:
  • Chronic/recurrent inflammation damages the filtration barrier
  • Mesangial activation + basement membrane thickening → progressive GFR decline
  • Heavy proteinuria emphasized (with hematuria and RBC casts as diagnostic clues later)

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Complications of progressive CKD

1) Metabolic acidosis

• Mechanism:
  • CKD reduces ability to handle bicarbonate (HCO₃⁻) and protons (H⁺):
    • Reabsorption of bicarb fails
    • Secretion/excretion of protons fails
  • Results:
    • pH decreases
    • bicarb decreases
    • protons increase
• Often described as anion gap metabolic acidosis in later CKD.
• Physiologic consequence: acidosis stimulates chemoreceptors → increased respiratory drive (Kussmaul-type breathing, “Teyia/Typia” in subtitles)
• Electrolyte consequence: proton–potassium exchange → potassium shifts out → risk of hyperkalemia
• Clinical threshold: worsening pH (< 7.2) highlighted as more concerning.

2) Hyperkalemia

• Mechanism: lower GFR → reduced ability to excrete potassium
• Cardiac risk emphasized:
  • AV node suppression and AV blocks
  • ECG progression described:
    1. Tall peaked T waves
    2. PR interval prolongation
    3. P-wave disappearance
    4. QRS widening → possible sine-wave pattern → possible ventricular fibrillation/cardiac arrest
• Dialysis becomes serious consideration when severe and not responding to therapy.

3) Hypervolemia / volume overload (“Hyperemia” in subtitles)

• Mechanism: CKD reduces ability to excrete sodium and water
• Complications:
  • Pulmonary edema (SOB, hypoxia; chest X-ray; crackles)
  • Pleural effusions
  • Peripheral edema / pitting edema (“tree trunk” swelling; pitting)
  • Jugular venous distension (JVD)
  • Hypertension from increased circulating volume
  • Possible hyponatremia
• Monitoring tip: daily weights to track fluid accumulation.

4) Uremia (clinical syndrome)

• Azotemia: lab elevation of waste products (e.g., BUN)
• Uremia: clinical manifestations
• When uremia is significant, it can affect:
  • Brain: altered mental status (lethargy → confusion → coma); asterixis
  • Heart/pericardium: uremic pericarditis
    • chest pain (improves leaning forward), radiates to trapezius
    • friction rubs, pericardial effusions
    • ECG pattern described: diffuse ST elevation and PR depression
  • Platelets: platelet dysfunction → higher bleeding risk
    • mucocutaneous bleeding, gingival bleeding, GI bleeding
    • procedures become high-risk

5) Secondary hypertension

• Mechanism (RAAS activation):
  • “Macula densa” senses low NaCl delivery → signals to JG cells → ↑ renin
  • ↑ renin → ↑ angiotensin II → vasoconstriction → ↑ BP
  • Angiotensin II also increases:
    • ADH (water reabsorption)
    • Aldosterone (sodium reabsorption)
• Net result: fluid retention + vasoconstriction → hypertension

6) Anemia of CKD

• Mechanisms:
  • Kidney injury → reduced erythropoietin (EPO) production
  • Chronic inflammation → increased hepcidin:
    • hepcidin reduces iron availability by inhibiting iron release from macrophages and affecting iron transport (ferroportin implied)
  • Iron deficiency contributes to anemia
• Clinical implication: symptomatic anemia emphasized when Hgb < 10 g/dL
• Need to consider iron deficiency as well as EPO deficiency.

7) CKD-related mineral bone disorder / hyperparathyroidism

• Shared concept: CKD → phosphate retention
  • CKD → phosphate rises (less filtration)
  • Reduced active vitamin D production → hypocalcemia → ↑ PTH
• Secondary hyperparathyroidism:
  • High phosphate
  • Low vitamin D
  • Low calcium
  • High PTH
• Tertiary hyperparathyroidism (progression):
  • Persistent stimulation → parathyroid hyperplasia/autonomy
  • High phosphate
  • Low vitamin D
  • High PTH
  • High calcium
• Bone complications:
  • Increased bone resorption via osteoclast activation
  • Osteitis fibrosa cystica
  • Osteopenia → osteoporosis
  • Pathologic fractures and bone pain
• Calciphylaxis:
  • Vascular calcification causing severe painful skin ulcers
  • Associated with CKD and mineral derangements (especially phosphate/calcium); warfarin noted as a risk factor in subtitles.

8) Hyperlipidemia / accelerated atherosclerosis risk

• Mechanism described:
  • Protein/albumin loss (albuminuria) → liver compensates → increased lipoproteins (LDL/VLDL)
  • Inflammation/endothelial dysfunction also contributes
• Outcome: accelerated atherosclerosis
  • increased risk of CAD/MI, stroke (TIA/CVA), and peripheral vascular disease

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Diagnostic approach (how to determine CKD + stage + cause)

Step 1: Evaluate GFR (renal function)

• Obtain a renal function panel.
• CKD diagnosis uses persistence criteria:
  • GFR < 60 mL/min/1.73m² persistent for ≥ 3 months
• Staging by GFR:
  • CKD 3A: 45–59
  • CKD 3B: 30–44
  • CKD 4: 15–29
  • CKD 5: < 15 (end-stage renal disease)
• Note: CKD 1/2 cannot be diagnosed using GFR alone if GFR is >60; evidence of injury is needed.

Step 2: Evidence of kidney damage (if GFR > 60)

Use:

• Albuminuria (albumin-to-creatinine ratio emphasized)
• Renal ultrasound
• Urinalysis/microscopy, including chronic injury casts (e.g., broad/waxy casts mentioned)

Step 3: Use albuminuria for prognosis

• Interpretation of albumin-to-creatinine ratio:
  • < 30: mild
  • 30–300: microalbuminuria
  • > 300: macroalbuminuria
• Teaching point:
  • Albuminuria can appear before a GFR drop → earlier detection
  • Higher albuminuria → worse prognosis and increased cardiovascular death risk

Step 4: Determine underlying cause

Use clinical context plus tests:

• Polycystic kidney disease: ultrasound with bilaterally enlarged kidneys and multiple cysts
• Diabetic nephropathy: elevated A1C
• Hypertensive nephropathy: persistently high BP with otherwise non-suggestive urinalysis/A1C for glomerulonephritis
• Glomerulonephritis: heavy protein with hematuria and RBC casts → biopsy may be needed if suspected

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Treatment approach (complications-first + stage progression)

General principle

Focus on:

1. Treating complications
2. Reducing progression
3. Preparing for renal replacement therapy if end-stage

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A) Management of metabolic acidosis / hyperkalemia / hypervolemia

Metabolic acidosis

• If pH < 7.2: treat with bicarbonate (bicarb)

Hyperkalemia

• Initial: low potassium diet
• If persistent:
  • Loop diuretics
  • Potassium-binding resins (mentioned)
• Monitoring: EKG and serum potassium
• Severe/refractory: consider dialysis

Hypervolemia / hypertension

• If pulmonary edema/peripheral edema:
  • Sodium restriction
  • Loop diuretics
• Monitor: daily weights and symptom/edema improvement

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B) Uremic bleeding

• For uremia with bleeding/procedure planning: desmopressin (DDAVP)

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C) RAAS blockade for hypertension and proteinuria

• ACE inhibitors or ARBs
  • lower angiotensin II effects → reduce vasoconstriction/BP
  • reduce aldosterone/ADH effects → reduce sodium/water retention
  • reduce proteinuria → slow progression
• Monitoring/risk:
  • hyperkalemia
  • possible decline in GFR / higher AKI risk

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D) Management of hyperparathyroidism / CKD mineral disease

• Low phosphate diet (first-line prevention)
• If phosphate remains high: phosphate binders
• Vitamin D analogs (calcitriol mentioned)
  • mainly if calcium and vitamin D are low
• Tertiary hyperparathyroidism:
  • cinacalcet to reduce PTH
  • parathyroidectomy if not possible/effective
  • mention of autotransplant to forearm in some cases

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E) Management of anemia in CKD

• If Hgb < 10 g/dL:
  • EPO + iron when needed
• Ensure iron stores:
  • ferritin > 100
  • transferrin saturation > 20%
• Goal: reduce need for packed RBC transfusions

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F) Medication safety / imaging precautions

• CKD increases risk of drug accumulation:
  • Avoid/minimize iodinated contrast if GFR < 60 (contrast-induced nephropathy risk)
  • Avoid gadolinium if GFR < 30 (nephrogenic systemic fibrosis risk)
• Renally dose medications to avoid toxicity

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Dialysis (end-stage CKD5) and renal replacement therapy details

When dialysis is considered

• “Refractory” complications or late-stage disease:
  • refractory acidosis
  • refractory hyperkalemia
  • refractory volume overload
  • uremic complications
  • end-stage renal disease (GFR < 15, CKD5)
• Kidney transplant may also be considered if a candidate.

Dialysis types described

Hemodialysis

• Access:
  • AV fistula (preferred long-term)
    • best long-term patency, lowest infection risk
    • maturation time: 4–6 weeks
  • AV graft
    • faster, higher stenosis/thrombosis risk
  • Central venous catheter
    • for urgent/emergent use
• Mechanism:
  • Diffusion emphasized (solute movement between blood and dialysate)
  • Convection/ultrafiltration also mentioned
• Schedule: typically 3 times/week
• Complications mentioned:
  • hypotension
  • dialysis disequilibrium syndrome:
    • rapid urea removal → osmotic shifts → water into cells → cerebral edema
  • access complications: infections (catheters), stenosis/clotting (catheters/AV graft)

Peritoneal dialysis

• Access: implanted peritoneal catheter
• Mechanism:
  • peritoneum acts as the dialysis membrane
  • dialysate dwells; wastes/solutes diffuse into it, then dialysate is drained (overnight described)
• Schedule: daily, often overnight
• Complication:
  • peritonitis (abdominal pain/distension; peritoneal fluid analysis; PMNs threshold mentioned as >250)

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Speakers / sources featured

• No other speakers are identified in the subtitles.
• The speaker appears to be a single narrator/presenter (name not given).