The Kidneys in Systemic Disease Flashcards
Why are the kidneys a particular target for many systemic diseases?
They receive more blood flow per unit volume than any other organ in the body
The glomeruli may filter proteins which are then reabsorbed by the tubule epithelial cells
The glomeruli may trap proteins or immune complexes
The kidney metabolises/excretes drugs which may be nephrotoxic
What are some of the systemic disease that affect the kidney?
Diabetes mellitus CV disease Infection Inflammation in blood vessels Haemolytic-Uremic Syndrome (HUS) Thrombotic Thrombocytopenic Purpura (TTP) Myeloma Amyloidosis
What cardiovascular diseases affect the kidney?
Cardiac failure
Atheroembolism
Hypertension
Atherosclerosis
What infections affect the kidney?
Sepsis
Post-infective glomerulonephritis
Infective endocarditis
What types of inflammation in the blood vessels affect the kidney?
SLE
Vasculitis
Scleroderma and other connective tissue diseases
Cryoglobulinaemia
What drugs affect the kidney?
Aminoglycosides ACEIs Penicillamine Gold NSAIDs Radiocontrast
What are the stages of diabetic nephropathy?
Development of proteinuria and decline in GFR
- Silent sub-clinical phase, hyperfiltration, increased GFR
- Microalbuminaemia (20-200ug/d)
- Clinical nephropathy (proteinuria > 0.5 g/d)
- Established renal failure
What percentage of people with type 1 diabetes will develop nephropathy within 10 years?
4%
What percentage of people with type 1 diabetes will develop nephropathy within 25 years?
25%
What percentage of people with type 2 diabetes will develop nephropathy within 5 years?
10%
What percentage of people with type 2 diabetes will develop nephropathy within 20 years?
30%
What percentage of people with diabetic nephropathy will progress to ESRF?
30%
What is the single commonest cause of end-stage renal failure?
Diabetes
What is increasing proteinuria in diabetic patients usually associated with?
Declining GFR
What is the single commonest cause of ESRF leading to the need for dialysis or transplant?
Diabetic nephropathy
What is stage 1 kidney disease?
Kidney damage/normal or high GFR
GFR > 90
What is stage 2 kidney disease?
Kidney damage/mild reduction in GFR
GFR 60-89
What is stage 3 kidney disease?
Moderately impaired
GFR 30-59
What is stage 4 kidney disease?
Severely impaired
GFR 15-29
What is stage 5 kidney disease?
Advanced or on dialysis
GFR < 15
What are the features of atheroembolic disease?
Common cause of renal failure in older patients Eosinophilia Peripheral skin lesions Warfarin therapy Vascular procedures
What is vasculitis?
Inflammatory reaction in the wall of any blood vessel
Defined by size of vessel involved
Can affect any single or multiple organs
Wide spectrum of clinical presentations
What are the types of vasculitis in the aorta/large arteries?
Takayasu arteritis
Giant cell arteritis
What are the types of vasculitis in medium sized arteries?
Polyarteritis nodosa
Kawasaki disease
What are the types of vasculitis in small vessels?
Granulomatous polyarteritis
Microscopic polyarteritis
Churg-Strauss syndrome
What are the features of granulomatous polyarteritis?
Granulomatous inflammation in the respiratory tract
Focal necrotising glomerulonephritis with crescents
Slightly more common in males
What age groups are affected by granulomatous polyarteritis?
All age groups affected but most common in 40-60s
What are the upper respiratory tract symptoms of granulomatous polyarteritis?
Epistaxis
Nasal deformity
Sinusitis
Deafness
What are the lower respiratory tract symptoms of granulomatous polyarteritis?
Cough
Dyspnoea
Haemoptysis
Pulmonary haemorrhage
What are the kidney symptoms of granulomatous polyarteritis?
Glomerulonephritis
What are the joint symptoms of granulomatous polyarteritis?
Arthralgia
Myalgia
What are the eye symptoms of granulomatous polyarteritis?
Scleritis
What are the heart symptoms of granulomatous polyarteritis?
Pericarditis
What are the systemic symptoms of granulomatous polyarteritis?
Fever
Weight loss
Vasculitic skin rash
What is the presentation of microscopic polyarteritis?
Similar clinical spectrum to granulomatous polyarteritis
Can present with systemic disease, renal and pulmonary involvement
More commonly renal-limited disease
How is vasculitis diagnosed?
Urine - blood/protein
Renal function - raised urea/creatinine
Biochemistry - raised alkaline phosphatase, CRP, low albumin
Haematology - anaemia, thrombocytosis, leukocytosis
Immunology - hyperglobulinaemia, positive ANCA
Renal biopsy
What are the typical causative organisms of infective endocarditis?
Staphylococcus aureus
Viridans streptococci
Enterococci
How does infective endocarditis lead to kidney problems?
Leads to glomerulonephritis +/- small vessel vasculitis due to immune complex formation
What suggests renal involvement in infective endocarditis?
Abnormal urea/creatinine
Haematuria, red cell casts
Reduced complement levels
What are the clinical features of multiple myeloma?
Markedly elevated ESR Anaemia Weight loss Fractures Infections Back pain/cord compression
How is multiple myeloma diagnosed?
Bone marrow aspirate > 10% clonal plasma cells
Serum paraprotein +/- immunoparesis
Urinary Bence-Jones protein
Skeletal survey - lytic lesions
What suggests renal failure in multiple myeloma?
Cast nephropathy Light chain nephropathy Amyloidosis Hypercalcaemia Hyperuricaemia
What features of the history might suggest a systemic disease with renal involvement?
Fever Malaise Weight loss Arthralgia Myalgia Skin rash Gritty eyes Breathlessness Haemoptysis Epistaxis Haematuria Oedema
What signs might suggest a systemic disease with renal involvement?
Splinter haemorrhages Purpura Raynaud's Scleritis Uveitis Nasal cartilage deformity Renal vasculitis Hypertensive retinopathy Vasculitis rash Scleroderma Hypertension Murmur Crepitations Haemoptysis Joint swelling Tenderness Stroke Encephalopathy
What initial investigations should be done when suspecting a systemic disease with renal involvement?
Urine - blood/protein on urinalysis, microscopy showing red cell casts
Blood - elevated urea/creatinine, raised CRP, thrombocytosis, anaemia, raised alkaline phosphatase
What further investigations should be done when suspecting a systemic disease with renal involvement?
Blood - ANCA, ANA, dsDNA antibodies, complement C3 and C4, blood cultures
Radiology - CXR, USS abdomen, CT thorax, echocardiography
Biopsy - kidney, nasal mucosa, lung, skin
