The Kidneys in Systemic Disease Flashcards
What is the most common cause of renal pathology?
Diabetic nephropathy
What is usually the first sign of diabetic nephropathy?
Microalbuminaemia
Why does renal hypertrophy occur in diabetes?
Plasma glucose stimulates growth factors in the kidney
(causing mesangial expansion, nodule formation and diffuse glomerlulosclerosis)
What is the cause of diabetic nephropathy?
High levels of glucose in the blood (can’t enter cells)
Why is excess glucose in the blood a problem (and reason) for developing diabetic nephropathy?
Non-enzymatic glycation occurs (as glucose alters surrounding proteins)
- Glucose passes throught he endothelium and has effects on the basement membrane
- This process if hyaline arteriosclerosis
- This makes arteries stiffer and increases filtration pressure
- This causes an increase in GFR called hyperfiltration
Why does hyperfiltration lead to damage in the kidneys?
Supportive mesangial cells secrete increased amounts of structural matrix expanding the glomerular size and causing spreading out of filtration slits of podocytes
This increases permeabilty of the basement membrane to proteins
This then decreases GFR as the blood cannot be filtered as effectively by the damaged glomeruli
In which two ways can excess structural matric be deposited in the kidneys during diabetic nephropathy?
- Uniformly
- Nodules called Kimmelstiel-Wilson nodules
What are the symptoms of diabetic nephropathy?
Hyperfiltration stage - Typically no symptoms
Eventually end stage renal failure will cause symptoms
Why do diabetics require regular screening for diabteic nephropathy?
There are no overt symptoms
Protein in the urine must be monitored (30-300mg of proteina day is microalbuminaemia and signifies the beginning of diabetic nephropathy)
Which medications can be used in diabetic nephropathy to slow disease proression?
ACEI
ARBs
What is ischaemic nephropathy?
Reduced GFR associated with reduced renal blood flow beyond the level of autoregulatory compensation
What are the main causes for ischaemic nephropathy?
- Essential hypertension
- Secondary hypertension
- Atherosclerotic renal artery stenosis
- Fibromuscular dysplasia
Which patients are generally affected by renal artery stenosis?
Older (>50) males
Renal artery stenosis is usually __________
Renal artery stenosis is usually unilateral
How do patients with renal artery stenosis present?
CKD in the elderly
Flash pulmonary oedema
Abdominal bruit (turbulent blood flow)
Athersclerotic disease elsewhere
Kidney size discrepancy
What are the two main causes for renal artery stenosis?
Atherosclerotic build up
Renal fibromuscular dysplasia
What is renal fibromuscular dysplasia?
Abnormal development of collagen and smooth mucle in the renal artery walls
How does renal fibromuscular dysplasia occur on imaging?
Renal artery appears like a string of beads
Who generally suffers from renal fibromuscular dysplasia?
Young females
How can renal artery stenosis be diagnosed?
Imaging
- USS
- Renal artery duplex studies
- CT/MRI angiography
Serum creatinine/urinalysis (for evidence of associated renal failure)
How can renal artery stenosis be treated?
Blood pressure management (ACEI)
Statin and anti-platelet agent
Balloon angioplasty
Renal artery bypass graft
Kidney removal
In which instance would ACEI not be used in renal artery stenosis?
Bilateral RAS
(Azotaemia risk increases - urea, creatinine, various body waste compounds, and other nitrogen-rich compounds build up in the blood)
Why is fibromusclular dysplasia often worse than renal artery stenosis caused by atherosclerotic reasons?
It is often bilateral
Which condition is renal fibromuscular dysplasia associated with?
Ehlers-Danlos
Whatis myeloma?
Cancer of plasma cells
How does multiple myeloma affect calcium levels?
Increases serum calcium
(due to bone breakdown)
Whta is the classic presentation of multiple myeloma?
Back pain and renal failure
What are the signs of multiple myeloma?
Anaemia
Hypercalcaemia
Renal failure
Amyloidosis
Recurrent infections
What are the main symptoms of multiple myeloma?
Bone pain
Weakness
Fatigue
Weight loss
Which different conditions can myeloma cause in the kidney?
AL amyloidosis (free light chain fibrils within glomerulus)
Light chain deposition disease (free light chain deposition along basement membrane)
Cast nephropathy (myeloma kidney) - Forms waxy casts in distal tubule lumen
Which blood tests can be done to diagnose multiple myeloma?
Serum protein electrophoresis
Serum free light chains
Which protein can be found in the urine that is suggestive of multiple myeloma?
Bence Jones protein
Besides blood tests and urinalysis, which other tests can be done to diagnose multiple myeloma?
Bone marrow biopsy
Skeletal survey
Renal biopsy
How can multiple myeloma be treated?
Chemotherapy
Stem cell transplant
Plasma exchange (removes light chains)
(hypercalcaemia must also be managed)
How do patients present with ANCA associated vasculitis?
Fever
Migratory arthralgia
Weight loss
Anorexia
Malaise
GPA involves which antibodies predominantly?
Anti-PR3
Where in the body does GPA predominantly affect?
Respiratory tract
(pulmnary/renal syndrome)
Microscopic polyangiitis is predominantly associated with which antibodies?
Anti-MPO
EGPA is associated with which other condition?
Asthma
What are the most frequent clinical manifestations in patients with lupus?
Fever and weight loss (100%)
MSK symmptoms - Arthralgias, synovitis, arthritis (95%)
Serosa - Pleuritis, pericarditis (80%)
Skin - Butterfly rash, photodermatosis, alopecia (75%)
Haematological - Anaemia, leukopenia, thrombocytopenia, thromboses (50%)
Kidney - proteinuria, nephrotoic syndrome, haemturia, hypertension, hyperkalaemia etc
What are the best differential diagnoses for SLE?
Sjogren’s syndrome
Fibromyalgia
Primary anti-phospholipid syndrome
Thrombotic micro-angiopathies
How many lupus patients develop lupus nephritis?
50%
What is the treatment for lupus nephritis?
Hydroxychloroquine
Steroids
Cyclophsophamide or mycophenalate mofetil
Azathioprine
