DIMS Lectures Renal Medicine PDF

Here is the complete pdf lecture of renal medicine by Dr. Tahir Malik

Introduction

Renal medicine, also known as nephrology, focuses on the diagnosis and management of kidney diseases. The kidneys play a crucial role in fluid balance, waste excretion, electrolyte regulation, and blood pressure control.

1. General Principles of Nephrology

Key Functions of the Kidney:

Filtration & Excretion: Removes toxins and metabolic waste (e.g., urea, creatinine).
Electrolyte Balance: Regulates sodium, potassium, calcium, and phosphate levels.
Acid-Base Homeostasis: Maintains blood pH by excreting hydrogen ions and reabsorbing bicarbonate.
Blood Pressure Regulation: Through the renin-angiotensin-aldosterone system (RAAS).
Erythropoiesis Stimulation: Produces erythropoietin (EPO) to enhance red blood cell production.

Key Diagnostic Tests in Nephrology:

Serum Creatinine & Blood Urea Nitrogen (BUN): Measures kidney function.
Estimated Glomerular Filtration Rate (eGFR): Assesses renal function severity.
Urinalysis: Detects proteinuria, hematuria, pyuria.
Electrolyte Panel: Evaluates sodium, potassium, bicarbonate abnormalities.
Renal Ultrasound: Checks for kidney size, hydronephrosis, cysts, or stones.
Renal Biopsy: Gold standard for diagnosing glomerulonephritis and systemic kidney diseases.

2. Common Renal Disorders

1. Acute Kidney Injury (AKI)

Definition: Sudden decline in kidney function, leading to increased creatinine and decreased urine output.
Causes:
- Pre-Renal: Dehydration, shock, heart failure.
- Renal (Intrinsic): Acute tubular necrosis (ATN), glomerulonephritis.
- Post-Renal: Obstruction (stones, BPH, tumors).
Diagnosis: Increased serum creatinine, decreased eGFR, urinalysis findings.
Management:
- Fluid resuscitation for pre-renal causes.
- Avoid nephrotoxic drugs (NSAIDs, aminoglycosides).
- Dialysis if severe (life-threatening electrolyte imbalance, acidosis).

2. Chronic Kidney Disease (CKD)

Definition: Progressive loss of kidney function lasting >3 months.
Staging (Based on eGFR):
- Stage 1: eGFR >90 (normal function with damage).
- Stage 2: eGFR 60-89 (mild decrease).
- Stage 3: eGFR 30-59 (moderate CKD).
- Stage 4: eGFR 15-29 (severe CKD).
- Stage 5: eGFR <15 (end-stage renal disease, ESRD).
Symptoms:
- Fatigue, edema, nausea, pruritus.
- Uremic symptoms: Confusion, pericarditis.
Management:
- Lifestyle Modifications: Low-sodium, low-protein diet.
- Medications: ACE inhibitors, erythropoietin for anemia, phosphate binders.
- Dialysis or kidney transplant for ESRD.

3. Nephrotic Syndrome

Definition: Proteinuria (>3.5g/day), hypoalbuminemia, edema, and hyperlipidemia.
Causes:
- Minimal Change Disease (MCD): Most common in children.
- Focal Segmental Glomerulosclerosis (FSGS): More common in adults.
- Membranous Nephropathy: Common in adults, associated with cancer and autoimmune diseases.
Diagnosis:
- Urinalysis: Heavy proteinuria.
- Serum Albumin: Low levels.
- Renal Biopsy: To determine underlying cause.
Management:
- Corticosteroids (First-line for MCD).
- Diuretics for edema.
- ACE inhibitors for proteinuria control.

4. Nephritic Syndrome

Definition: Hematuria, oliguria, hypertension, mild proteinuria.
Causes:
- Post-Streptococcal Glomerulonephritis: Occurs after Group A Strep infection.
- IgA Nephropathy: Common cause of recurrent hematuria in young adults.
- Rapidly Progressive Glomerulonephritis (RPGN): Crescentic glomerulonephritis with poor prognosis.
Diagnosis:
- Urinalysis: RBC casts, mild proteinuria.
- Complement Levels: Low in post-streptococcal GN.
- Renal Biopsy: Confirms diagnosis.
Management:
- Supportive care for post-strep GN.
- Corticosteroids + Immunosuppressants (Cyclophosphamide) for RPGN.

5. Kidney Stones (Nephrolithiasis)

Types:
- Calcium oxalate (most common).
- Uric acid (associated with gout).
- Struvite (infection stones from Proteus bacteria).
Symptoms: Severe flank pain radiating to the groin, hematuria.
Diagnosis:
- Non-contrast CT Abdomen (Gold Standard).
- Urinalysis: RBCs, crystals.
Management:
- Hydration, pain control (NSAIDs, opioids).
- Medical Expulsion Therapy: Alpha-blockers (Tamsulosin) for stones <10mm.
- Surgical Removal for Large Stones: Lithotripsy, ureteroscopy.

Case Example :

1. A 50-year-old male presents with severe hypertension, generalized edema, and foamy urine for 2 months. Examination shows periorbital swelling, ascites, and leg edema.

2. A 30-year-old male reports cola-colored urine, fever, and recent sore throat. Examination reveals hypertension and mild leg swelling.

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1. Diagnosis: Nephrotic Syndrome (Likely Membranous Nephropathy)
2. Diagnosis: Post-Streptococcal Glomerulonephritis