Topics: Classification of Renal Diseases, Acute Tubular Necrosis, Acute Pyelonephritis, Chronic pyelonephritis Subject: Pathology Course: RDT IInd year

1. RENAL DISEASES
Dr. Salman Ansari
MBBS

2. List of topics
● Classification of renal diseases
● Acute Tubular Necrosis
● Acute Pyelonephritis
● Chronic Pyelonephritis

3. Classification of kidney disorders
● Congenital malformations: simple renal cyst, Adult polycystic
kidney disease
● Tubulo-interstitial diseases: acute tubular necrosis(ATN), acute
pyelonephritis, chronic pyelonephritis
● Glomerular diseases: different types of glomerulonephritis,
nephrotic syndrome, nephritis syndrome
● Obstructive uropathy
● Renal vascular diseases
● Tumours of kidney

4. Anatomy
● Unit of kidney - nephron
● Nephron consists of glomerulus, tubule and collecting system
● Glomerulus is the filtering unit

8. Tubular and tubulointerstitial diseases
● Tubular disease: ATN
● Tubulointerstitial: acute pyelonephritis, chronic pyelonephritis

9. Acute Tubular Necrosis
● Definition
● Causes
● Pathogenesis
● Clinical course
● Prognosis

10. Acute Tubular Necrosis
● Also called Acute Kidney Injury(AKI), acute tubular injury(ATI)
● Destruction of tubular epithelial cells resulting in acute renal
failure
● Most common cause of acute renal failure
● Rapid reduction in renal function with severe oliguria(less than 400
ml/day)

11. Etiology
1. Ischemia(ischemic ATN): due to blood loss, severe burns, septic
shock
2. Direct toxic injury(nephrotoxic ATN): antibiotics, heavy
metals(mercury, lead)
3. Combination of ischemic and nephrotoxic AKI
4. Acute tubulointerstitial nephritis
5. Urinary obstruction: tumours

12. Pathogenesis
1. Injury to tubule epithelial cells: due to ischemia or toxins
Leads to backleak of fluid into interstitium
->obstruction of lumen by detached epithelial cells
->increased intratubular pressure
->decrease in GFR -> oliguria
1. Disturbance in blood flow
Ischemia causes vasoconstriction and reduced blood supply to
tubules

14. Clinical course
1. Initiation phase: mild reduction of urine output and increase in BUN
2. Maintenance phase: sustained decrease in urine output in the range of
40 to 400 mL/day (oliguria), salt and water overload, rising BUN level,
hyperkalemia, metabolic acidosis, and other features of uremia

15. 3. Recovery phase:
● steady increase in urine volume, which may reach up to 3 L/day
● Loss of large amounts of water, sodium and potassium (leading to
hypokalemia) in the urine.
● BUN and creatinine levels also start to return to normal.

16. Prognosis
Can be reversed with treatment and most patients recover

17. ACUTE PYELONEPHRITIS

18. Acute Pyelonephritis
● Definition
● Etiology
● Pathogenesis
● Clinical features and Diagnosis

20. Definition
Acute infection of the kidney affecting the tubules, interstitium, and renal
pelvis.
● Can be acute or chronic
● Bacterial infection commonly

21. Etiology
Causative organisms:
● Gram-negative bacilli
● E.coli, Klebsiella, Enterobacter
Route of infection:
● ascending infection from lower urinary tract
● Less common: hematogenous spread

22. Risk factors

23. Pathogenesis
● Bacteria from perineum spread to lower urinary tract due to poor
hygiene and colonise it
● spread from lower tract to upper tract via catheterisation/trauma/reflux
● Multiply in upper urinary tract and cause infection(acute
pyelonephritis)
● Leads to Acute kidney injury(AKI)

24. Clinical features
● Fever
● Sudden onset of pain in abdomen
● Dysuria, frequency and urgency

25. Lab findings
Urine analysis: pus cells, WBC casts
Bacterial C/S: to find out organism and which antibiotic it is sensitive to
Treatment:
Antibiotics - oral or intravenous
Supportive measures

26. Complications

27. CHRONIC PYELONEPHRITIS

28. Chronic pyelonephritis
Chronic inflammation of tubulointerstitial tissue leading to scarring
of calyces, pelvis and renal parenchyma.
● important cause of end-stage renal disease

29. Types
2 types
1. Reflux nephropathy (chronic reflux-associated pyelonephritis)
2. Chronic obstructive pyelonephritis
● Develops due to recurrent infections superimposed on obstructive
lesions, which lead to renal inflammation, parenchymal atrophy and
scarring.

30. Morphology
Kidney is shrunken and scarred

31. Clinical features
● Back-pain
● Fever
● pyuria
● bacteriuria

32. Diagnosis
● Culture is usually sterile
● Intravenous pyelography(IVP) for diagnosis

33. Irregular scar
Small contracted kidney

34. Sources:
● Ramadas Nayak - Undergraduate
Prep Manual
● Harsh Mohan - Textbook of
Pathology
Questions:
salman.s.ansari92@gmail.com
For notes: