Kidneys in systemic disease Flashcards
What are some systemic causes of CKD?
Myeloma
Amyloidosis
Vasculitis
SLE
What is myeloma?
A haematological cancer in which there is clonal expansion of plasma cells causing production of clinical immunoglobulins (M-proteins)
What are some symptoms of myeloma?
- Bone pain
- Weakness
- Fatigue
- Weight loss
- Recurrent infections
What are some signs of myeloma?
- Anaemia
- Hypercalcaemia
- Renal failure
- Lytic bone lesions
What causes renal impairment in myeloma (20-40%)?
- Glomerular - Monoclonal immunoglobulin deposition
- Tubular - Light chain cast nephropathy
- Misc. - Dehydration, hypercalcaemia, contract, bisphosphonates and NSAIDs
What investigations are required in myeloma?
Bloods
Urine
Bone marrow biopsy
Skeletal survey
Renal biopsy
What blood tests in particular are required in myeloma?
Serum protein electrophoresis
Serum free light chains
What will be seen in urine in myeloma?
Bence-Jones proteins (Clonal light chains)
What are some management options of renal impairment in myeloma?
Stop nephrotoxic drugs
Manage hypercalcaemia
Chemotherapy or stem-cell transplant
Dialysis
What is amyloidosis?
This is the deposition of extracellular amyloid (Insoluble protein fibrils) in the tissues or organs
Describe the pathophysiology of amyloidosis
Abnormal folding of proteins which then aggregate and become insoluble
Breakdown of usual degredation pathways for abnormally folded proteins
What re the 4 most common forms of amyloidosis?
- Primary / Light chain (AL)
- Secondary / Systemic / Inflammatory (AA)
- Dialysis (Aß2M)
- Hereditary and old age (ATTR)
Describe the pathway of primary (Light chain) amyloidosis (AL)
Unknown factor causes monoclonal B-lymphocyte proliferation
This causes monoclonal plasma cell formation
This causes release of immunoglobulin light chains (Bence-Jones) which is deposited in the kidneys causing damage
Describe the pathway of secondary/systemic/inflammatory amyloidosis (AA)
Chronic inflammation causes macrophage activation
Macrophages release IL-1 and IL-6
This causes liver cells to release SAA protein which build up in the kidneys causing damage
Renal presentation of amyloidosis
Nephrotic proteinuria +/- Impaired renal function
Cardiac presentation of amyloidosis
cardiomyopathy
Nervous presentation of amyloidosis
Peripheral or autonomic neuropathy
Gastrointestinal presentation of amyloidosis
- Hepatomegaly/Splenomegaly
- Malabsorption
What investigations are required in amyloidosis?
Urinalysis + PCR
Blood tests - RFT, Inf markers, protein electrophoresis
Renal biopsy
SAP scan
What test is performed on renal biopsy in amyloidosis?
Congo red staining → Apple green under polarised light
What is a SAP scan?
Scintigraphy with radiolabelled serum amyloid to show extent of the disease
How is AA amyloidosis managed?
Treat underlying condition
How is AL amyloidosis managed?
Immunosuppression - Steroids, chemotherapy, stem cell transplant
What is systemic lupus erythematosus (SLE)?
This is a chronic auto-immune inflammatory disease of unknown origin
What systems can be affected by SLE?
skin, joints, kidneys, lungs, nervous system and serous membranes
Who is most at risk of SLE?
Most commonly affects women aged 20-30 and African Americans and Hispanics
What tests are required in SLE?
- Blood tests - Raised inflammatory markers, immunology (Anti-dsDNA) , complement system markers
- Urinalysis - Proteinuria +/- microscopic haematuria
What percentage of SLE patients have renal involvement?
50%
What is renal impairment due to SLE called?
Lupus nephritis
What are the 6 ISN classes of lupus nephritis?
- Class I - Minimal mesangial
- Class II - Mesangial proliferative
- Class III - Focal proliferative
- Class IV - Diffuse proliferative
- Class V - Membranous
- Class VI - Advanced sclerosing
How is lupus nephritis managed?
Immunosuppression
