T4-L4: Renal Pathology Flashcards
Give causes of vascular damage.
- Diabetes
- Hypertension
- Vasculitis
- Atheroma e.g. renal artery stenosis
- Thrombotic microangiopathy - here there is thrombi in the capillaries/arterioles Endothelial damage may be due to bacterial toxins, drugs, complete or clotting abnormalities.
Give causes of glomerular damage.
Can be immunological or non-immunological in origin.
Immunological causes: (larger causes)
- Circulating immune complexes deposit in the glomerulus e.g. in SLE or IgA/membranous nephropathy
- Circulating antigens deposit in the glomerulus
- Antibodies to the BM/glomerular components e.g. post-infective glomerolunephritis
Non-immunological causes:
- Endothelial damage e.g. HTN, vasculitis
- Altered basement membrane e.g. DM hyperglycaemia
- Abnormal BM or podocytes due to inherited disease
- Abnormal protein deposition
Give causes of tubular damage.
Tubules are quite metabolically active as so are sensitive to ischemia. Other causes of damage may be related to toxins.
Ischaemic causes: - HTN e.g. shock - Vessel damage e.g. vasculitis, HTN - Glomerular Damage Blood supply to the tubules is via peritubular arteries via the afferent arteries and so diseases that cause glomerular arteries eventually cause tubular damage by reduced perfusion.
Toxins:
- Direct toxins e.g. drugs, heavy metals, organic solvents etc.
- Hypersensitivity reaction to drugs
- Crustal deposits e.g. utrate
- Abnormal protein deposition e.g. Ig’s
What are the signs/symptoms and complications of nephrotic syndrome?
Signs and symptoms:
- Proteinuria
- Oedema
- Hypoalbuminaemia
May also see:
- HTN
- Hyperlipidaemia
Complications include infection and thrombosis - in the protein loss we tend to lose factors that help fight infection.
What are the causes of nephrotic syndrome in adults and children?
Adults:
- Most common cause is Membranous nephropathy - primary (associated with antibodies) or secondary (associated with viral infection or neoplasm)
- Focal segmental glomerulosclerosis - primary (abnormality of the podocytes) and secondary (due to drugs, viral infections, increased body mass etc.)
- Minimal change disease
Children:
- Minimal change disease
- Focal Segmental Glomerulosclerosis
- Other causes are rare
What are the signs/symptoms of acute nephritis?
- Haematuria
- Proteinuria (less than that in nephrotic syndrome)
- Oedema
- HTN
- Acute Renal Failure
Give causes of nephritis in adults and children.
Adults:
- Post-infective glomerulonephritis - antibodies to group A step in airway throat infection cross react
- IgA nephropathy
- Vasculitis
- SLE
Children:
- Post-infective glomeronephritis
- IgA nephropathy
- Henoch-Schonlein purpura - An IgA vasculitis that is typically a disease of young boys/teenagers.
- Haemolytic uremic syndrome - thrombosis in the kidney. Typically occurs following an E-coli infection in children. It usually also presents with thrombocytopenia and haemolysis.
Give causes of acute renal failure.
Repaid degeneration of renal function sometimes in a few hours, days or a week. May present with anuria/oliguria. Also raised creatinine and urea - malaise, fatigue, nausea and vomiting and due to electrolyte balance arrythmias. Cause can be pre-renal, renal or post-renal.
Pre-renal causes: Severe dehydration, Hypovolaemia and Hypotension
Renal causes: In adults causes include vasculitis and acute intestinal nephritis. In children causes include Henoch-Scholein purpua, Haemolytic uraemia syndrome and acute intestinal nephritis.
Post renal causes: Obstruction of the urinary tract.
What are complications of acute renal failure?
- Cardiac failure (fluid overload)
- Arrythmias (electrolyte imbalance)
- Liver failure (hepatic venous congestion)
- GI bleeding (multifactorial)
- Infection (loss of inflammatory mediators)
What are the effects of chronic renal failure?
- Reduced excretion of electrolytes and water (HTN and oedema)
- Renal bone disease (phosphate calcium)
- Reduced excretion of toxic metabolites
- Anaemia - due to loss of production of erythropoietin
What are causes of isolated proteinuria?
- May be bengin e.g. postural, related to pyrexia or exercise
- May be due to renal disease e.g. adults: FSGS, DM and SLE; in children FSGS or HSP
What are causes of isolated haematuria?
Can present with or without proteinuria with normal renal function.
Causes:
- IgA nephropathy
- Thin basement membrane disease: inherited condition causing abnormally thin glomerular BM; renal function usu. normal
- Alport hereditary nephropathy: inherited abnormalities of type IV collagen cause abnormal BM, sometimes with eye and ear problems - renal failure +/- deafness +/- ocular problems
Thin basement membrane disease and Alport’s are type 4 collagen disease.
Other causes include malignancy.
What are the risk factors and complications of pyelonephritis?
Infection of the kidney. This can be acute or chronic. Risk factors particular ascending are instrumentation of the urethra, diabetes and urinary tract structural abnormalities.
Acute pyelonephritis
Risk factors: female (ascending infection), instrumentation, diabetes, UT structural abnormalities.
Can lead to abscess formation.
Chronic pyelonephritis:
Risk factors: Urinary tract obstruction or reflux.
Complications include scarring and chronic renal failure.
What are complications of renal artery stenosis?
Leads to poor perfusion of the kidney. Most commonly due to atheroma, also arterial dysplasia. Ischaemia of the kidney causes activation of RAAS leading o HTN leading to further damage and scarring.
How can vasculitis affect the kidney?
Inflammation in glomerular vessels can cause clotting + obliteration of capillary lumena and glomerulus destruction.
Inflammation of larger renal arterioles can cause tubule hypoxia.
