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Renal Pathology


Introduction: • 150gm: each kidney • 1700 liters of blood filtered  180 L of G. filtrate  1.5 L of urine / day. • Kidney is a retro-peritoneal organ • Blood supply: Renal Artery & Vein • One half of kidney is sufficient – reserve • kidney function: Filtration, Excretion, Secretion, Hormone synthesis.


Kidney Location:


Kidney Anatomy:


Renal Pathology Outline • Glomerular diseases: Glomerulonephritis • Tubular diseases: Acute tubular necrosis • interstitial diseases: Pyelonephritis • Diseases involving blood vessels: Nephrosclerosis • Cystic diseases • Tumors


Clinical Syndromes: • Nephritic syndrome. – Oliguria, Haematuria, Proteinuria, Oedema.

• Nephrotic syndrome. – Gross proteinuria, hyperlipidemia,

• Acute renal failure – Oliguria, loss of Kidney function - within weeks

• Chronic renal failure. – Over months and years - Uremia


Introduction • Functions of the kidney: – excretion of waste products – regulation of water/salt – maintenance of acid/base balance – secretion of hormones

• Diseases of the kidney – glomeruli – tubules – interstitium – vessels


Abnormal findings • Azotemia: ↑ BUN, creatinine • Uremia: azotemia + more problems • Acute renal failure: oliguria • Chronic renal failure: prolonged uremia


Nephrotic syndrome

Nephritic syndrome

• Massive proteinuria • Hypoalbuminemia

• Hematuria • Oliguria

• Edema • Hyperlipidemia/-uria

• Azotemia • Hypertension


Glomerular diseases – Nephrotic syndrome • Minimal change disease • Focal segmental glomerulosclerosis • Membranous nephropathy – Nephritic syndrome

• Post-infectious GN • IgA (immune) nephropathy


Nephrotic Syndrome

• Massive proteinuria • Hypoalbuminemia • Edema • Hyperlipidemia


Causes • Adults: systemic disease (diabetes) • Children: minimal change disease • Characterized by loss of foot processes • Good prognosis


Minimal change disease


Minimal change disease

Normal glumerular structure


Minimal change disease

Normal glomerulus


Focal Segmental Glomerulosclerosis • Primary or secondary • Some (focal) glomeruli show partial (segmental) hyalinization • Unknown pathogenesis • Poor prognosis


Focal segmental glomerulosclerosis


Membranous Glomerulonephritis

• Autoimmune reaction against unknown renal antigen • Immune complexes • Thickened GBM • Subepithelial deposits


Membranous glomerulonephritis


Nephritic Syndrome

• Hematuria • Oliguria, azotemia • Hypertension


Causes • Post-infectious GN, IgA nephropathy • Immunologically-mediated • Characterized by proliferative changes and inflammation


Post-Infectious Glomerulonephritis

• Child after streptococcal throat infection • Immune complexes • Hypercellular glomeruli • Subepithelial humps


Post-infectious glomerulonephritis


IgA Nephropathy • Common! • Child with hematuria after (URI) Upper Respiratory Infection • IgA in mesangium • Variable prognosis


IgA nephropathy


• Tubular and interstitial diseases – Inflammatory lesions • pyelonephritis


Pyelonephritis

• Invasive kidney infection • Usually ascends from UTI • Fever, flank pain • Organisms: E. coli, Proteus


Urinary Tract Infection • Women, elderly • Patients with catheters or mal-formations • Dysuria, frequency • Organisms: E. coli, Proteus


Acute pyelonephritis with abscesses


Pyelonephritis


Cellular cast


Chronic pyelonephritis


Drug-Induced Interstitial Nephritis

• Antibiotics, NSAIDS • IgE and T-cell-mediated immune reaction • Fever, eosinophilia, hematuria • Patient usually recovers • Analgesic nephritis is different (bad)


Drug-induced interstitial nephritis


Acute Tubular Necrosis • The most common cause of ARF! • Reversible tubular injury • Many causes: ischemic (shock), toxic (drugs) • Most patients recover


Acute tubular necrosis


Benign Nephrosclerosis

• Found in patients with benign hypertension • Hyaline thickening of arterial walls • Leads to mild functional impairment • Rarely fatal


Benign nephrosclerosis


Malignant nephrosclerosis • Arises in malignant hypertension • Hyperplastic vessels • Ischemia of kidney • Medical emergency


Malignant Hypertension • 5% of cases of hypertension • Super-high blood pressure, encephalopathy, heart abnormalities • First sign often headache, scotomas • Decreased blood flow to kidney leads to increased renin, which leads to increased BP! • 5y survival: 50%


Malignant hypertension


Adult Polycystic Kidney Disease

• Autosomal dominant • Huge kidneys full of cysts • Usually no symptoms until 30 years • Associated with brain aneurysms.


Adult polycystic kidney disease


Childhood Polycystic Kidney Disease

• Autosomal recessive • Numerous small cortical cysts • Associated with liver cysts • Patients often die in infancy


Childhood polycystic kidney disease


Medullary Cystic Kidney Disease • Chronic renal failure in children • Complex inheritance • Kidneys contracted, with many cysts • Progresses to end-stage renal disease


• Tumors – Renal cell carcinoma – Bladder carcinoma


Renal Cell Carcinoma

• Derived from tubular epithelium • Smoking, hypertension, cadmium exposure • Hematuria, abdominal mass, flank pain • If metastatic, 5y survival = 5%


Renal cell carcinoma


Bladder Carcinoma

• Derived from transitional epithelium • Present with painless hematuria • Prognosis depends on grade and depth of invasion • Overall 5y survival = 50%


Bladder carcinoma


6- Renal pathophysiology