(CKD)Chronic kidney disease -

Chronic Kidney Disease (CKD)

🔍 Definition

Chronic Kidney Disease (CKD) is defined as:

Abnormalities in kidney structure or function present for ≥3 months, with health implications.

✅ KDIGO 2012 Definition

CKD is present if either:

GFR <60 mL/min/1.73 m² for ≥3 months, with or without kidney damage
Markers of kidney damage (even if GFR ≥60), e.g.:

Albuminuria (UACR ≥30 mg/g)
Urine sediment abnormalities
Electrolyte abnormalities due to tubular disorders
Histologic abnormalities
Structural abnormalities (e.g., PKD)
History of kidney transplantation

📊 CKD Staging: KDIGO 2012 GFR Categories

Stage	GFR (mL/min/1.73 m²)	Description
G1	≥90	Normal or high (with evidence of damage)
G2	60–89	Mildly decreased (with damage)
G3a	45–59	Mild–moderate ↓
G3b	30–44	Moderate–severe ↓
G4	15–29	Severely ↓
G5	<15	Kidney failure (ESRD if dialysis-dependent)

🧪 Albuminuria Categories (KDIGO)

Category	UACR (mg/g)	Description
A1	<30	Normal–mild
A2	30–300	Moderate (microalbuminuria)
A3	>300	Severe (macroalbuminuria)

✅ CKD is graded by GFR + albuminuria → used to stratify prognosis and progression risk

🔬 Pathophysiology

CKD involves progressive nephron loss, leading to:

Compensatory hyperfiltration → glomerular hypertension → sclerosis
Fibrosis from chronic inflammation
Tubulointerstitial injury
Activation of RAAS → systemic and glomerular HTN
Uremic toxin accumulation → systemic effects

📉 Etiologies of CKD

Common Causes	Examples
Diabetes Mellitus (Type 1/2)	Diabetic nephropathy
Hypertension	Hypertensive nephrosclerosis
Glomerular diseases	IgA nephropathy, FSGS, lupus nephritis
Tubulointerstitial disease	Chronic pyelonephritis, drug-induced
Cystic diseases	ADPKD
Obstructive uropathy	Stones, BPH, tumors
Vascular diseases	Renal artery stenosis, atheroemboli

🧾 Clinical Features

System	Manifestations
Renal	Polyuria (early), oliguria (late), hematuria, foamy urine
Metabolic	Acidosis, hyperkalemia, hypocalcemia, hyperphosphatemia
CVS	HTN, LVH, pericarditis, CAD
Hematologic	Normocytic anemia (↓ EPO), platelet dysfunction
GI	Anorexia, N/V, uremic gastritis
Neuro	Encephalopathy, peripheral neuropathy, restless legs
Derm	Pruritus, uremic frost
Bone	CKD-MBD (renal osteodystrophy)

🔍 Investigations

Modality	Purpose
Serum Creatinine, eGFR	Kidney function
UACR or 24-h protein	Albuminuria grading
USG KUB	Kidney size, echogenicity, obstruction
CBC	Anemia
Ca, Phos, PTH	Bone–mineral axis
ABG	Metabolic acidosis
Renal biopsy	When diagnosis unclear or glomerular disease suspected

💊 Drug Dosing in CKD (General Rules)

Drug Type	Action
Avoid	NSAIDs, metformin (if GFR <30), contrast (if possible)
Reduce dose	Aminoglycosides, digoxin, vancomycin, LMWH
Safe	β-lactams (with adjustment), acetaminophen
Monitor	Electrolyte-altering drugs: ACEi/ARBs, spironolactone

💉 Anemia in CKD

Caused by ↓ EPO, chronic inflammation, blood loss
Target Hb: 10–11.5 g/dL (not >13)
Treatment:

Epoetin alfa: 50–100 IU/kg 2–3x/week SC/IV
Darbepoetin alfa: 0.45 mcg/kg weekly or biweekly
Iron supplementation if ferritin <100 ng/mL or TSAT <20%

🦴 CKD-MBD (Bone Disease)

Hypocalcemia, hyperphosphatemia, ↑ PTH → bone resorption
Treatment:

Phosphate binders: Sevelamer, calcium acetate
Vitamin D analogs: Calcitriol (0.25–1 mcg/day)
Calcimimetics: Cinacalcet for high PTH

⚡️ Hyperkalemia in CKD

Causes: ↓ excretion, RAS inhibitors, acidosis, diet
Treatment:

Calcium gluconate 10 mL IV over 5–10 min
Insulin + 25–50 mL Dextrose 50%
Salbutamol neb
Furosemide IV
Dialysis if severe/refractory

💧 Fluid & Electrolyte Management

Use balanced crystalloids if needed
Monitor Na, K, HCO₃ daily
Be cautious with volume overload; loop diuretics as needed

🚨 When to Refer to Nephrology

GFR <30 mL/min/1.73 m²
Rapid progression (decline >5 mL/min/year)
Refractory hypertension, hyperkalemia, acidosis
Suspected glomerulonephritis
ESRD planning (dialysis, transplant)

🏥 When to Start Dialysis in CKD

Based on clinical criteria, not just GFR:

“AEIOU” mnemonic:

A: Metabolic Acidosis
E: Electrolyte (esp. K⁺) imbalance
I: Intoxications (e.g., lithium)
O: Volume Overload
U: Uremic symptoms (encephalopathy, pericarditis)

💊 Drugs in Renal Failure: What’s Safe, What’s Not

✅ Category 1: Generally SAFE (No Adjustment Needed)

Drug Class	Examples
Analgesics	Acetaminophen (paracetamol)
Antibiotics	Ceftriaxone, Clindamycin, Azithromycin, Doxycycline
Cardiac drugs	Amlodipine, Metoprolol, Diltiazem
GI drugs	PPIs (omeprazole), Antacids (non-Mg-based), Domperidone
Endocrine	Insulin (but monitor), Glipizide (short-acting sulfonylurea)
Antiepileptics	Valproate, Carbamazepine, Levetiracetam (monitor levels)
Anticoagulants	Warfarin, Unfractionated Heparin (UFH)
Miscellaneous	Lorazepam, Haloperidol, Prednisolone

⚠️ Even “safe” drugs may need monitoring for efficacy or toxicity, especially in ESRD or dialysis patients.

⚖️ Category 2: REQUIRES DOSE ADJUSTMENT

Drug Class	Examples	Notes
Beta-lactam antibiotics	Penicillins, Cephalosporins, Carbapenems	Adjust based on GFR
Aminoglycosides	Gentamicin, Amikacin	Risk of nephrotoxicity; monitor trough levels
Fluoroquinolones	Ciprofloxacin, Levofloxacin	Risk of seizures if unadjusted
Vancomycin	—	TDM essential
LMWH	Enoxaparin	Anti-Xa monitoring preferred in ESRD
Anti-TB drugs	Ethambutol, Pyrazinamide	INH & Rifampin are usually safe
Oral Hypoglycemics	Sitagliptin, Gliclazide	Dose based on eGFR
Antivirals	Acyclovir, Tenofovir	Risk of crystal nephropathy
Antifungals	Fluconazole, Amphotericin B (liposomal preferred)	Adjust fluconazole; amphotericin = nephrotoxic
Digoxin	—	High risk of toxicity; adjust & monitor levels
Allopurinol	—	Risk of toxicity (SJS/TEN) in CKD
Gabapentinoids	Gabapentin, Pregabalin	Accumulate in CKD → CNS side effects
Metformin	—	Safe if GFR >30; stop during AKI/contrast exposure

❌ Category 3: AVOID or USE WITH EXTREME CAUTION

Drug Class	Examples	Why?
NSAIDs	Ibuprofen, Diclofenac, Indomethacin	↓ GFR, risk of AIN/ATN
ACEi/ARBs	Enalapril, Losartan	Use cautiously in AKI, bilateral RAS
Potassium-sparing diuretics	Spironolactone, Amiloride	Hyperkalemia risk
Certain oral hypoglycemics	Glyburide (glibenclamide)	Prolonged hypoglycemia
Magnesium-based antacids	—	Risk of hypermagnesemia
Nitrofurantoin	—	Ineffective + toxicity in low GFR
Metformin (GFR <30)	—	Risk of lactic acidosis
Contrast media	Iodinated contrast	Risk of contrast-induced nephropathy
Bisphosphonates	Zoledronate	Avoid in CrCl <30 mL/min
Colchicine	—	Neurotoxicity risk in ESRD
Lithium	—	Excreted by kidneys, narrow therapeutic index