Other Renal Pathology

Question 1

State three differentials for asymptomatic haematuria

Answer 1

Thin basement membrane disease (benign familial haematuria), IgA nephropathy (Berger disease), Alport syndrome (hereditary nephritis)

Question 2

Describe acute tubular necrosis (ATN)

Answer 2

Damage to tubular epithelial cells causing cell shedding, blocking the renal tubules and leading to reduced blood flow and increased haemodynamic pressure in the nephron. This reduces the pressure across the basement membrane, leading to acute renal failure

Question 3

What is the most common cause of acute renal failure?

Answer 3

Acute tubular necrosis

Question 4

State the two main causes of acute tubular necrosis

Answer 4

Hypovolaemia, nephrotoxins (e.g. aminoglycosides, NSAIDs, radiographic contrast agents, myoglobin, heavy metals)

Question 5

Describe the histology of acute tubular necrosis

Answer 5

Necrosis of short segments of renal tubules

Question 6

State the four types of tubulointerstitial nephritis

Answer 6

Acute pyelonephritis, chronic pyelonephritis, acute interstitial nephritis, chronic interstitial nephritis

Question 7

Define acute pyelonephritis

Answer 7

Bacterial infection of the kidney, most commonly ascending infection with E coli

Question 8

Describe the symptoms of acute pyelonephritis

Answer 8

Fever, chills, sweats, flank pain, renal angle tenderness, leucocytosis, urinary frequency, dysuria, haematuria

Question 9

Define chronic pyelonephritis

Answer 9

Chronic inflammation and scarring of the parenchyma caused by recurrent and persistent bacterial infection

Question 10

State the two main causes of chronic pyelonephritis

Answer 10

Chronic obstruction (e.g. posterior urethral valves, renal calculi), urine reflux

Question 11

Define acute interstitial nephritis

Answer 11

A hypersensitivity reaction, usually to a drug, occurring days after exposure

Question 12

Describe the clinical features of acute interstitial nephritis

Answer 12

Fever, skin rash, haematuria, proteinuria, eosinophilia

Question 13

Describe the clinical features of chronic interstitial nephritis

Answer 13

Asymptomatic

Late in disease: hypertension, anaemia, proteinuria, haematuria

Question 14

State the cause of chronic interstitial nephritis

Answer 14

Long-term analgesic consumption in the elderly

Question 15

Name two thrombotic microangiopathies

Answer 15

Haemolytic-uraemic syndrome (HUS), thrombotic thrombocytopaenic purpura (TTP)

Question 16

Describe the characteristics of thrombotic microangiopathies

Answer 16

Thrombosis, and a triad of microangiopathic haemolytic anaemia (MAHA), thrombocytopaenia, and renal failure

Question 17

State three differences between HUS and TTP

Answer 17

Epidemiology: HUS more common in children, TTP more common in adults
Thrombi: HUS confined to kidneys, TTP thrombi throughout circulation (especially CNS)
Renal: HUS causes renal failure, TTP usually no renal failure

Question 18

Describe the pathophysiology of thrombotic microangiopathies

Answer 18

The platelet surface protein ADAMTS3 mediates widespread fibrin deposition in vessels, leading to the formation of platelet-fibrin thrombi which damage passing platelets and red blood cells, leading to platelet and red blood cell destruction

Question 19

Describe the clinical features of thrombotic microangiopathies

Answer 19

Bleeding, petechiae, haematemesis, melaena, pallor, jaundice

Question 20

How are thrombotic microangiopathies diagnosed?

Answer 20

Low haemoglobin, low platelets, increased bilirubin, increased reticulocyte count, increased lactate dehydrogenase, fragmented red blood cells on blood smear, Coomb’s test negative (excludes autoimmune haemolytic anaemia)

Question 21

Define acute renal failure

Answer 21

A rapid loss of renal function manifesting as increased serum creatinine and urea

Question 22

State at least 3 complications of acute renal failure

Answer 22

Metabolic acidosis, hyperkalaemia, fluid overload, hypertension, hypocalcaemia, uraemia

Question 23

What is the most common cause of acute renal failure?

Answer 23

Hypoperfusion

Question 24

State three renal causes of acute renal failure

Answer 24

Acute tubular necrosis, acute glomerulonephritis, thrombotic microangiopathy

Question 25

State at least three post-renal causes of acute renal failure

Answer 25

Renal stones, tumours, prostatic hypertrophy, retroperitoneal fibrosis - all cause obstruction

Question 26

Define chronic renal failure

Answer 26

Progressive, irreversible loss of renal function characterised by prolonged symptoms and signs of uraemia (fatigue, itching, anorexia, eventually confusion)

Question 27

State the five most common causes of chronic renal failure, in order

Answer 27

Diabetes, glomerulonephritis, hypertension/ vascular disease, reflux nephropathy, polycystic kidney disease

Question 28

State the GFR for each stage of chronic renal failure

Answer 28

1: >90
2: 60-89
3: 30-59
4: 15-29
5: <15/ on renal replacement therapy

Question 29

Which genes are involved in adult polycystic kidney disease? (APCKD)

Answer 29

85% of cases: PKD1 on chromosome 16, encoding polycystin-1

15% of cases: PKD2 on chromosome 4, encoding polycystin-2

Question 30

Describe the pathological features of adult polycystic kidney disease

Answer 30

Large multicystic kidneys with destroyed renal parenchyma, berry aneurysms. In PDK1, liver cysts

Question 31

Describe the clinical features of adult polycystic kidney disease

Answer 31

Usually due to complications: Haematuria, flank pain, UTI

Question 32

Describe the clinical features of lupus nephritis

Answer 32

Depending on site of immune complex deposition: urinary abnormalities, acute renal failure, nephrotic syndrome, progressive chronic renal failure

Question 33

Describe class I lupus nephritis (minimal mesangial)

Answer 33

Immune complexes but no structural alteration

Question 34

Describe class II lupus nephritis (mesangial proliferative)

Answer 34

Immune complexes and a mild-moderate increase in mesangial matrix and cellularity

Question 35

Describe class III lupus nephritis (focal)

Answer 35

Active swelling and proliferation in less than half the glomeruli

Question 36

Describe class IV lupus nephritis (diffuse)

Answer 36

Active swelling and proliferation in more than half the glomeruli

Question 37

Describe class V lupus nephritis (membranous)

Answer 37

Subepithelial immune complex deposition

Question 38

Describe class VI lupus nephritis (advanced sclerosing)

Answer 38

Complete sclerosis of >90% of the glomeruli

Question 39

Describe the clinical features of renal cell carcinoma

Answer 39

Costovertebral pain, palpable mass, haematuria.

Paraneoplastic syndrome causes polycythaemia, hypercalcaemia, hypertension, Cushing’s syndrome, and amyloidosis