Other Renal Pathology Flashcards
State three differentials for asymptomatic haematuria
Thin basement membrane disease (benign familial haematuria), IgA nephropathy (Berger disease), Alport syndrome (hereditary nephritis)
Describe acute tubular necrosis (ATN)
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
What is the most common cause of acute renal failure?
Acute tubular necrosis
State the two main causes of acute tubular necrosis
Hypovolaemia, nephrotoxins (e.g. aminoglycosides, NSAIDs, radiographic contrast agents, myoglobin, heavy metals)
Describe the histology of acute tubular necrosis
Necrosis of short segments of renal tubules
State the four types of tubulointerstitial nephritis
Acute pyelonephritis, chronic pyelonephritis, acute interstitial nephritis, chronic interstitial nephritis
Define acute pyelonephritis
Bacterial infection of the kidney, most commonly ascending infection with E coli
Describe the symptoms of acute pyelonephritis
Fever, chills, sweats, flank pain, renal angle tenderness, leucocytosis, urinary frequency, dysuria, haematuria
Define chronic pyelonephritis
Chronic inflammation and scarring of the parenchyma caused by recurrent and persistent bacterial infection
State the two main causes of chronic pyelonephritis
Chronic obstruction (e.g. posterior urethral valves, renal calculi), urine reflux
Define acute interstitial nephritis
A hypersensitivity reaction, usually to a drug, occurring days after exposure
Describe the clinical features of acute interstitial nephritis
Fever, skin rash, haematuria, proteinuria, eosinophilia
Describe the clinical features of chronic interstitial nephritis
Asymptomatic
Late in disease: hypertension, anaemia, proteinuria, haematuria
State the cause of chronic interstitial nephritis
Long-term analgesic consumption in the elderly
Name two thrombotic microangiopathies
Haemolytic-uraemic syndrome (HUS), thrombotic thrombocytopaenic purpura (TTP)
Describe the characteristics of thrombotic microangiopathies
Thrombosis, and a triad of microangiopathic haemolytic anaemia (MAHA), thrombocytopaenia, and renal failure
State three differences between HUS and TTP
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
Describe the pathophysiology of thrombotic microangiopathies
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
Describe the clinical features of thrombotic microangiopathies
Bleeding, petechiae, haematemesis, melaena, pallor, jaundice
How are thrombotic microangiopathies diagnosed?
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)
Define acute renal failure
A rapid loss of renal function manifesting as increased serum creatinine and urea
State at least 3 complications of acute renal failure
Metabolic acidosis, hyperkalaemia, fluid overload, hypertension, hypocalcaemia, uraemia
What is the most common cause of acute renal failure?
Hypoperfusion
State three renal causes of acute renal failure
Acute tubular necrosis, acute glomerulonephritis, thrombotic microangiopathy
