Dr. Roopam Jain, Professor & Head, Dept. of Pathology & Blood Bank

1. The KIDNEY
TUBULAR & TUBULOINTERSTITIAL
DISEASES
DR. ROOPAM JAIN
PROFESSOR & HEAD, PATHOLOGY

2. TUBULAR &
TUBULOINTERSTITIAL
DISEASES

3. TUBULAR & TUBULOINTERSTITIAL
DISEASES
• parenchymal diseases is discussed under 2 headings:
• I. Primary tubular diseases
• that include tubular injury by ischaemic or toxic agents i.e. acute tubular
necrosis.
• II. Tubulointerstitial diseases
• that include inflammatory involvement of the tubules and the
interstitium i.e. pyelonephritis (acute and chronic)

4. ACUTE TUBULAR NECROSIS
• ATN is the term used for acute renal failure (ARF) resulting from
destruction of tubular epithelial cells.
• ATN is the most common and most important cause of ARF
• characterised by sudden cessation of renal function. Various other
causes of ARF (pre-renal, intra-renal and post-renal)

5. ACUTE
TUBULAR
NECROSIS
PATHOGENESIS

6. Contrasting features of ischaemic & toxic ATN

7. Ischaemic
ATN
There is focal necrosis along the nephron involving PCT as well as DCT.
The affected tubules are dilated, their lumina contain casts (hyaline or
pigmented haem) and the affected regions are lined by regenerating thin and
flat epithelium.

8. Toxic
ATN
There is extensive necrosis of epithelial cells involving predominantly
PCT diffusely.
The necrosed cells are desquamated & undergo dystrophic calcification

9. TUBULOINTERSTITIAL
DISEASES

10. • The term tubulointerstitial nephritis is used for inflammatory process
that predominantly involves the renal interstitial tissue and is usually
accompanied by some degree of tubular damage.

11. Tubulointerstitial
diseases

12. Acute Pyelonephritis
• acute suppurative inflammation of the kidney caused by pyogenic bacteria
• ETIOPATHOGENESIS
• Most cases of acute pyelonephritis follow infection of the lower urinary tract.
• The most common pathogenic organism in urinary tract infection (UTI) is
Escherichia coli (in 90% of cases), followed in decreasing frequency, by
Enterobacter, Klebsiella, Pseudomonas and Proteus.
• The bacteria gain entry into the urinary tract, and then into the kidney by
one of the two routes: ascending infection & haematogenous infection (Fig.)

13. Acute Pyelonephritis

14. Acute Pyelonephritis
CLINICAL FEATURES
• an acute onset with chills, fever, loin pain, lumbar tenderness, dysuria
and frequency of micturition.
• Urine will show abundance of bacteria, pus cells and pus cell casts in the
urinary sediment.
• Institution of specific antibiotics, after identification of bacteria by
culture followed by sensitivity test, eradicates the infection in majority of
patients.

15. Acute Pyelonephritis
COMPLICATIONS
• 1. Papillary necrosis
• 2. Pyonephrosis (Fig.)
• 3. Perinephric abscess
Pyonephrosis.
The kidney is enlarged & has increased perinephric fat in the hilum.
Sectioned surface shows markedly dilated pelvis and calyces having irregular and
ragged inner surface and containing necrotic debris and pus.

16. Chronic Pyelonephritis
• chronic tubulointerstitial disease resulting from repeated attacks of infl
ammation and scarring.
ETIOPATHOGENESIS
• Depending upon the etiology and pathogenesis, two types of chronic
pyelonephritis
• Reflux nephropathy
• Obstructive pyelonephritis (Fig.)

17. A, Vesicoureteric reflux causing infection of peripheral
papillae & consequent scars at the poles of the kidney.

18. B, Obstructive pyelonephritis due to obstruction of the urinary tract
causing high pressure backflow of urine and infection of all the
papillae and consequent diffuse scarring of the kidney and thinning
of the cortex.

19. Small contracted kidney in chronic pyelonephritis with calyectasis.
A, Diagrammatic representation.

20. Small contracted kidney in chronic pyelonephritis with calyectasis.
B, External surface of small and contracted kidney. The kidney is small in
size and contracted. The capsule is adherent to the cortex and has irregular
scars on the surface.
C, Sectioned surface shows dilated pelvi-calyceal system with atrophied
and thin peripheral cortex

21. Chronic pyelonephritis.
The scarred area shows atrophy of some tubules and dilatation of
others which contain colloid casts (thyroidisation). The tubules are
surrounded by abundant fibrous tissue and chronic interstitial inflammatory
reaction.
The blood vessels included are thick-walled and the glomeruli show
periglomerular fi brosis