An intro to glomerular diseases Flashcards
What is glomerulonephritis
-Glomerular inflammation
-Generally caused by immunological mediated injury to the glomeruli
-Pathogenic mechanism: deposition of circulating or in situ formation of immune; deposition of antiglomerular basement membrane abs
(These mechanisms activate secondary mechanisms that lead to the glomerular damage &inflammation)
-Pattern of injury and the clinical presentation will depend on the ‘target’ of the immune response
How can we classify glomerulonephritis
- ) PRIMARY eg membranous
2. ) SECONDARY- as part of a generalized disease eg SLE
How may someone with glomerular disease present?
- hypertension
- incidental finding of proteinuria
- incidental finding of microscopic haematuria
- Nephrotic syndrome
- Progressive renal impairment
- Acute kidney injury
What is nephrotic syndrome
A collection of symptoms due to kidney damage
- hyperlipidaemia
- Oedema( children=periorbital; adults=peripheral)
- Hypoalbuminuaemia
- Heavy proteinuria>3.5g per day
- If you have 3+ protein on urine dipstick and someone with oedema, it’s almost always going to be nephrotic syndrome
- A leak of protein through your kidney cos the podocyte pores(these usually hang onto protein) get disrupted and the protein leaks through into the urine freely
- Basically an increase in protein leak associated with oedema
What may be a consequence or renal artery stenosis
renal hypertension
Why would you consider checking complements if a pt presents to you with incidental hypertension
To check for SLE
Why would you consider checking ANCA if a pt presents to you with incidental hypertension
To check for vasculitis
What is IgA nephropathy?
- aka Berger’s disease
- occurs when IgA lodges in your kidney
- Results in local inflammation that, over time, may hamper your kidneys’ ability to filter wastes from your blood
- Could cause and incidental finding of hypertension
What are some causes of secondary hypertension
- endocrine causes
- renal artery stenosis
What are some non-glomerular causes of microscopic haematuria ?
- Bladder tumours
- Renal stones
- Renal tumors
- BPH
- UTI
- Renal injury
What are some of the primary glomerular causes of microscopic haematuria
- IgA nephropathy
- Alports
- Thin basement membrane disease
- Post infectious GN
- Membranoproliferative GN
What are some of the secondary glomerular causes of microscopic haematuria
- Henoch Scorlein Purpura (IgA vasculitis)
- SLE
- HUS
- ANCA
- Sickle nephropathy
Outline the pathogenesis of IgA nephropathy
-Glomerular deposition of IgA causing inflammation
Outline the clinical presentation of IgA nephropathy
Variable clinical presentation
- Microscopic haematuria
- Hypertension
- Slowly progressive renal impairment
- Rapidly progressive renal impairment
- Nephrotic range proteinuria
What lab tests may be useful for IgA nephropathy
- Raised serum IgA
- Renal biopsy shows mesangial proliferation with IgA deposition
How can we manage IgA nephropathy?
- Control of BP
- Immunosuppression may be useful
Outline the characteristics of Henoch Schonlein Purpura
- Inflammation of the small blood vessels esp in kidneys,skin and gut
- Most common in young children
- IgA deposition in the kidney in a similar pattern to IgA nephropathy
- Associated with a leucocytoclasic vasculitic rash
- Variable prognosis, some fully recover with resolution of the rash and renal findings, others progress to ESKD
Define leucocytoclasic
‘To be destroyed by WBCs’
-eg IgA vasculitis; the small vessels are destroyed by IgA antibodies
What are the primary causes of nephrotic syndrome?
- Membranous nephropathy
- FSGS(focal segmental glomerulosclerosis)
- MCGN (Mesangiocapillary glomerulonephritis)
- Minimal change disease
What are the secondary causes of nephrotic syndrome?
- Diabetic nephropathy
- SLE
- Amyloidosis
- Malignancy
- Drugs
What are the possible complications of nephrotic syndrome?
- Protein malnutrition
- Hypovolaemia
- AKI (esp older pts with min change disease)
- VTE
- Infections
Describe the management of nephrotic syndrome
- Diuretics
- ACE
- Anticoagulation
- Statin
- Renal biopsy (in children minimal change disease is common so steroids are given before the biopsy)
What is the most common cause of nephrotic syndrome in children?
Minimal change disease (90%)
What are the most common causes of nephrotic syndrome in adults
FSGS(35%) Membranous nephropathy(33%)
What is minimal change disease?
- Sudden onset oedema especially in children
- Normal light microscopy
- Foot process effacement of podocytes on EM
Outline the causes of minimal change disease
- Ideopathic(majority), esp kids
- NSAIDs
- Lithium,pellicinamine,pamidronate, sulfazalizine,immunizations
- Paraneoplastic (Hodgkins lymphoma)
- Infections (syphillis, TB, mycoplasma, Hep C)
- Allergy
What is FSGS
- Focal segmental glomerulosclerosis
- This is a lesion, not a disease
- A lot of cases have nephrotic syndrome with it
- Light microscopy shows focal and segmental areas of mesangial collapse and sclerosis
- Very common in blacks
What are the possible causes of FSGS?
-Idiopathic-usually presents with nephrotic syndrome
Secondary (non-nephrotic proteinuria, hypertension, microscopic haematuria and renal insufficiency more common presentations)
- HIV infection(collapsing)
- Reflux nephropathy
- Massive obesity
- Scaring from previous insult eg IgA, vasculitis, Lupus
- Heroin
What is membranous nephropathy
- Most common cause of primary nephrotic syndrome in adults
- Basement membrane thickening, little or no cellular expansion
- Electron dense deposits in the GBM (represent immune deposits)
- Ideopathic-antiPLA2 ab associated
- Secondary- hepB, autoimmune diseases (inc SLE), thyroiditis, carcinomas, gold,penicillamine,captopril, NSAIDs
Define exsanguination
severe loss of blood
How can we treat hyperkalaemia ?
- Calcium gluconate to protect your heart & prevent him getting arrhythmias
- Insulin will drive K into cells (but you’re not removing the K you’re just moving it into a different compartment, so you then need to think about removing the K excess)
- Dextrose to replace loss fluids & provide carbs for the body
- It is the extracellular K that’s dangerous and can cause arrhythmias
Outline ANCA positive vasculitis
- Granulomatosis with polyangitis (GPA)
- Microscopic polyangitis
- Rapidly progressive GN with crescent formation
- ANCA= anti neutrophil cytoplasmic abs and these have been shown to be pathogenic
What is anti GBM disease
- Auto antibodies to the glomerular basement membrane causing a rapidly progressive glomerular nephritis with crescent formation
- Previously known as good pastures syndrome
- Associated with anti GBM abs and alveolar basement membrane abs
- Can cause absolute anuria with pulmonary haemorrhage (or only AKI or pulmonary haemorrhage)
How can the colour of the urine on a urine dipstick be useful?
- Visible haematuria
- Frothy suggests proteinuria
- Cloudy may suggest infection
- Coca cola colour suggests rhabdomyolysis
Why may the urine specific gravity be useful in a urine dipstick?
- ) high= increased conc of solutes in the urine eg glucose in diabetes or dehydration
- ) If low can suggest GN or diabetes insipidus (but non-specific and not greatly helpful)
What blood tests may be useful in suspected glomerular disease?
- Blood cultures
- U&E, LFT, Bone profile
- Virology
- RF
- C3 &C4
- ANCA
- Anti GBM
- Myeloma screen (Igs,Electrophoresis & urine Bence-Jonce proteins)
What is rheumatoid factor?
-Antibodies directed against the Fc portion of IgG (usually IgM)
What are the different ways gomerular disease can present in
- ) Acute vs chronic
- ) Idiopathic vs secondary
- ) Incidental finding vs acute presentation
- ) Nephrotic (proteinuria) vs nephritic (haematuria)
