Kidneys in Systemic Disease Flashcards
What are the three main systemic diseases that involve the kidney?
Diabetic nephropathy
Lupus nephritis
Multiple myeloma
What is diabetic nephropathy?
A kidney complication of both type one diabetes mellitus and type two diabetes mellitus
It involves chronic high levels of glucose passing through the glomerulus and causing scarring
Describe the pathophysiology of diabetic nephropathy
Diabetes mellitus patients have a raised concentration of glucose within their blood
This hyperglycaemia results an increased production of glycosylation end products and growth factors which cause haemodynamic and hormone changes within the kidneys.
These changes specifically include hyperfiltration and hypertension, which causes the glomerulus to leak out albumin (albuminuria) and depositions to accumulate within the extracellular matrix
Overtime, this will result in inflammation of the glomerulus – which leads to interstitial fibrosis and glomerulosclerosis
What lesions are found in diabetic nephropathy?
Kimmelsteil-Wilson nodules
What are the four risk factors of diabetic nephropathy?
Hypertension
Smoking
Hypercholesterolaemia
Family History
What are the seven clinical features of diabetic nephropathy?
Proteinuria, which is the presence of protein within the urine – specifically the presence of more than 0.5g/d of albumin.
Polyuria, which is an increased urine output > 3L per 24hrs
Peripheral Oedema
Hypertension
Pruritus, which is defined as persistent itching of the skin
Nausea & Vomiting
Fatigue
What four investigations are used to diagnose diabetic nephropathy?
Blood Tests
Urine Tests
CT scan
Renal Biopsy
What are the two blood tests used to diagnose diabetic nephropathy?
eGFR, which would be decreased
Serum Creatinine, which would be elevated
What urine test result indicates diabetic nephropathy?
Albuminuria
This is specifically defined as an albumin level greater than 0.5g/d
How are CT scans used to diagnose diabetic nephropathy?
It determines if the kidney’s structure is abnormal and whether it is functioning effectively
What is a renal biopsy?
It involves the insertion of a thin needle into the kidneys to collect a tissue sample
What are the two signs of diabetic nephropathy on renal biopsy?
Kimmelsteil-Wilson nodules
Fibrosis
What are the three complications of diabetic nephropathy?
End Stage Kidney Disease
Cardiovascular Complications, such as heart failure and hypertension
Hyperkalaemia
What is lupus nephritis?
A common complication of systemic lupus erythematosus in which lupus autoantibodies affect structures in the kidneys
This kidney damage can result in albumin and haemoglobin leaking from the kidneys into urine
It is an autoimmune condition, specifically a form of immune-mediated glomerulonephritis
Is lupus nephritis a nephrotic or nephritic syndrome?
Nephrotic syndrome
What are the three risk factors of lupus nephritis?
Gender, with women having an increased risk
Age, with individuals between the ages of 15-45 being the most commonly affected
Ethnicity, with individuals of African, Caribbean or Asian descent having an increased risk
What are the five clinical features of lupus nephritis?
Haematuria, which is the presence of blood in the urine resulting in pink coloured urine.
Proteinuria, which is the presence of protein in the urine resulting in the appearance of foamy urine.
Hypertension, which is elevated blood pressure levels
Malor Rash, which is a rash present over the cheeks and nose
Joint Pain & Swelling
What are the three investigations used to diagnose lupus nephritis?
Blood Tests
Urine Test
Kidney Biopsy
What are the two blood tests used to diagnose lupus nephritis?
eGFR, which would be decreased
Serum Creatinine, which would be elevated
What are the two urine tests used to diagnose lupus nephritis?
Proteinuria, which is the presence of protein in urine. This is specifically defined as a protein level greater than 0.5g/d.
Microscopic Haematuria, which is the presence of blood in urine. This is specifically defined as more than three RBCs per high power field.
How is renal biopsy used to diagnose lupus nephritis?
It allows the classification of lupus nephritis to be determined
This classification determines the immunosuppression treatment prescribed to the patient
What are the two treatments of lupus nephritis?
Immunosuppresion
Hypertensive agents
What are immunosuppressants?
They slow or stop the immune system from attacking healthy cells.
What are the five immunosuppressants used to treat lupus nephritis?
Prednisolone
Cyclosporine
Tacrolimus
Cyclophosphamide
Azathioprine
What are the two hypertensive agents used to treat lupus nephritis?
ACE inhibitors
ARBs
What are the two complications of lupus nephritis?
Cardiovascular Complications
End Stage Kidney Disease
What is multiple myeloma?
A malignancy of plasma cells
What is the function of plasma cells?
They fight infections within the body through the production of antibodies and immunoglobulin proteins
Describe the pathophysiology of multiple myeloma
A cancerous plasma cell undergoes monoclonal proliferation in an uncontrolled manner
This results in the accumulation of plasma cells in bone marrow, crowding out the healthy tissue
Bone marrow is involved in the production of red blood cells and therefore multiple myeloma leads to complications of anaemia and impaired immune function
How does multiple myeloma mainly affect the kidneys?
Cast nephropathy
What is cast nephropathy?
It occurs when the proteins produced by the clone of plasma cells pass into the tubules of the kidney
In the kidney, these proteins join up with another type of protein, which is physiologically present in urine, Tamm-Horsfall protein
This results in the formation of large protein casts, which cause an inflammatory reaction within the kidney tubules and therefore obstruction
What are the other two mechanisms in which multiple myeloma affect the kidneys?
Neprocalcinosis
Amyloidosis
What is neprocalcinosis?
This is due to plasma cells secreting factors that activate osteoclasts.
Osteoclasts are involved in breaking down bone, which results in the release of calcium and therefore hypercalcaemia.
This hypercalcaemia means that more calcium needs to be filtered by the kidneys, therefore leading to kidney damage.
What is amyloidosis? How does it affect the kidney?
Amyloidosis occurs due to plasma cells secreting amyloid proteins, which can then accumulate in organs and tissue throughout the body – including the kidney.
This accumulation of amyloid disrupts kidney function.
What are the five risk factors of multiple myeloma?
Age, with individuals of an increasing age having an increased age – with most people diagnosed in their mid 60s.
Gender, with males having an increased risk
Ethnicity, with individuals of Black descent having an increased risk
Family History
Certain Conditions, such as monoclonal gammopathy of undetermined significance (MGUS)
What are the five clinical features of multiple myeloma?
Anaemia, which results in individuals becoming tired and weak
Bone Pain, which most commonly affects the spine and chest
Weight Loss
Bone Fractures
Recurrent Infections
Why does multiple myeloma result in bone fractures?
This is due to healthy bone marrow tissue being crowded out by the cancerous plasma cells
Why does multiple myeloma result in recurrent infections?
This is due to a hyperactive immune system caused by multiple myeloma
What are the four investigations used to diagnose multiple myeloma?
Blood Tests
Urine Tests
Bone Marrow Aspirate
X-Ray
What are the four blood tests used to diagnose multiple myeloma?
M Proteins, which are proteins produced by myeloma cells and will therefore be elevated in multiple myeloma
Beta 2-Microglobulin, which is an abnormal protein produced by myeloma cells. It will indicate the severity of the myeloma.
Serum ESR, which will be elevated
Serum Paraprotein, which will be elevated and appears as a distinct band on protein electrophoresis.
What urine test result indicates multiple myeloma?
The presence of Bence Jones protein (BJP), which is a specific abnormal protein produced by myeloma cells.
What is a bone marrow aspirate?
It involves the insertion a long needle into bone, which enables a sample of bone marrow to be collected
This sample is then examined in a lab
What bone marrow aspirate result indicates multiple myeloma?
> 10% of plasma cells
What x-ray scan indicates multiple myeloma?
Skeletal lytic lesions in bone
