Acute nephritis, glomerulonephritis and acute tubular necrosis

Question 1

Nephritic syndrome definition

Answer 1

Characterised by:
- Haematuria
- Proteinuria
- Leucosuria

Question 2

Acute interstitial nephritis
- Description
- Causes

Answer 2

Inflammation of the renal interstitium (between renal tubules)
- Commonly caused by hypersensitivity to medication

Causes:
- Drug allergy: antibiotics (beta-lactam, fluroquinolones)
- PPIs
- NSAIDs
- Chemo
- AI/ inflammatory disease: Sjorgren, TINU, sarcoid
- Infective: staph, strep, Brucella.

Question 3

Acute interstitial nephritis
- Presentation

Answer 3

Mild renal impairment
- Poor renal function= worse prognosis

If drug reaction, allergy picture
- Rash, fever, peripheral eosinophilia.

Oedema
- if NSAIDs used, presents with nephrotic syndrome

Question 4

Investigations for acute interstitial nephritis

Answer 4

Definite diagnosis= biopsy
- Inflammatory cell infiltrate in interstitium

Question 5

Nephritic causes of glomerulonephritis

Answer 5

IgA nephropathy

Post-infectious GN

Rapidly progressive GN

Question 6

Rapidly progressive GN
- Description
- Causes

Answer 6

Characterised by rapid decrease in eGFR

Causes
- Type 3: ANCA related vasculitis: granulomatosis with polyangitis (Wegner’s), microscopic polyangiitis

• Type 1: anti-GBM autoantibodies= Goodpasture syndrome,

Type 2: Immune complex deposition: SLE, IgA nephropathy

Question 7

Treatment of Rapidly progressive GN

Answer 7

Rituximab

Corticosteroids

Cyclophosohamide
- azathioprine

Question 8

Post-infectious GN
- Description
- Histology
- Causes

Answer 8

Type 3 hypersensitivity reaction
- Antibodies bind to sites on glomerulus and activates complement

Histology
- Proliferative GN: proliferation of endothelium and mesangium.

Causes
- Streptococcal infection (weeks post-infection)

Question 9

Pathophysiology of acute tubular necrosis

Answer 9

Ischaemia or nephrotoxic injury to the renal tubules leading to death of tubular endothelial cells.

Question 10

Acute tubular necrosis causes

Answer 10

Reduced perfusion
- Dehydration
- Circulatory shock
- Massive haemorrhage

Nephrotoxins
- Aminoglycoside antibiotics
- Contrast dye
- Rhabdomyolysis

Question 11

The most common pathological cause of an AKI is…

Answer 11

Acute tubular necrosis

Question 12

State the phases of acute tubular necrosis

Answer 12

Oliguria/anuric phase
- Damage to tubular cells= less filtration and urine production

Polyuric phase
- Tubular cells are regenerated, leading to increased urine production

Recovery phase
- Urine output returns back to baseline

Question 13

Urinalysis findings for acute tubular necrosis

Answer 13

“Muddy brown casts”

Proteinuria

Urine osmolality <350

Question 14

Histopathological findings of acute tubular necrosis

Answer 14

Necrotic, epithelial tubular cells
- loss of nuceli

Detached tubular cells

Dilated tubules

Question 15

Chronic interstitial nephritis is most commonly caused by…

Answer 15

Prolonged use of NSAIDs

Question 16

Urine studies findings for interstitial nephritis

Answer 16

May show eosinophilia in hypersensitivity reaction

White cell casts

Proteinuria, haematuria

Question 17

Kidney ultrasound in interstitial nephritis will show…

Answer 17

Increased cortical echogenicity

Question 18

IgA nephropathy is also known as…

Answer 18

Berger’s disease

Question 19

Causes/ associations of IgA nephropathy

Answer 19

Upper respiratory tract infection
- Typically occurs within days

Coeliac disease

HIV

Alcoholic liver disease

Question 20

IgA nephropathy presentation

Answer 20

Nephritic syndrome

Macroscopic haematuria

AKI

Question 21

Nephrotic syndrome causes of glomerulonephritis

Answer 21

• Minimal change disease
• Focal segmental glomerulosclerosis
• Membraneous GN
• Membranoproliferative GN

Question 22

Nephritic syndrome causes of glomerulonephritis

Answer 22

Mesangial proliferative/ IgA nephropathy

Post-infectious/ diffuse proliferative GN

Rapidly progressive/ crescentic GN

Question 23

Focal segmental glomerulosclerosis (FSGS) pathology

Answer 23

Segmental glomerular scarring and podocyte damage.

Question 24

Renal biopsy in minimal change disease will show

Answer 24

Loss of podocyte processes/ fusion of podocytes

Question 25

What treatment is effective in most cases of minimal change disease?

Answer 25

High dose prednisolone

Question 26

Management of post-infectious GN

Answer 26

Typically self-limiting disease so management is supportive

Question 27

Renal histology findings in membranous GN

Answer 27

Immunofluorescence
- Granular IgG deposits
- C3 deposits