Pathology I Flashcards
What is nephritis?
Inflammation of the kidney = infective (pyelonephritis) or non-infective (glomerulonephritis)
What is glomerulonephritis?
Inflammation of the glomerulus
What are the main causes of glomerulonephritis?
Immune mediated = directed at something in the glomerulus, circulating complex deposition
Related to vasculitis
What are some features of direct attack by the immune system causing glomerulonephritis?
Rare = Goodpasture’s syndrome (alpha subunit of collagen 4, IgG antibodies)
What are some causes of glomerulonephritis caused by circulating immune complexes?
Hepatitis, post-strep infection, HIV, gold, penicillamine, cancer (often lymphoma)
What vasculitis cause glomerulonephritis?
GPA = cANCA
Microscopic polyangiitis = pANCA
What does glomerulonephritis prevent?
Stop glomerular sieve working = disrupt membrane charge, block membranes
How is glomerulonephritis classified?
Nephrotic or nephritic syndrome
What are the features of nephritic syndrome?
Haematuria, hypertension
What are the features of nephrotic syndrome?
Heavy proteinuria, non-dependent oedema, hyperlipidaemia, immunosuppression, renal vein thrombosis
What proteins are lost in nephrotic syndrome?
Antibodies, complement, proteins in clotting cascade
How is glomerulonephritis investigated?
Using light microscopy, electron microscopy and immunofluorescence
Can the types of glomerulonephritis cause both nephrotic and nephritic syndromes depending on the person they occur in?
Yes = all can cause a nephritic or nephrotic syndrome but have a tendency to cause one or the other
What do crescents on histology mean in glomerulonephritis?
Poor prognostic sign = indicates rapid progression
What are some causes of granulomas in glomerulonephritis?
GPA and sarcoid
What does light microscopy of glomerulonephritis show?
Usually hypercellular = inflammatory cells and reactive proliferation
Can see sclerosis (on-going damage) or crescents
May be able to see vasculitis
What is the benefit of using electron microscopy in glomerulonephritis?
High magnification = can look at basement membrane
Can see if there are deposits and where they are
What does immunofluorescence show?
What kind of antibody is present and where it is distributed
What does immunofluorescence of Goodpasture’s show?
Linear IgG
What are some features of minimal change glomerulonephritis?
Nephrotic syndrome of unknown cause = occurs in children, good prognosis, usually resolves with steroids
What are some features of focal segmental glomerulosclerosis?
Nephrotic syndrome of adults = causes include obesity, HIV, sickle cell and IV drug use
What are some causes of membranous glomerulonephritis?
Hepatitis, malaria, syphilis, NSAIDs, penicillamine, gold, captopril, lung/colon cancer, melanoma, SLE, thyroiditis
How common is membranous glomerulonephritis in patients with SLE?
Accounts for 15% of all glomerulonephritis in lupus patients
What is membranous glomerulonephritis?
Nephrotic syndrome of adults = thick membrane and sub-epithelial deposits
What is the prognosis of membranous glomerulonephritis?
Variable = slow indolent progression, <40% eventually develop renal failure
What is IgA glomerulonephritis?
Post-infectious nephritic syndrome = may be genetic or due to acquired defect (coeliac), prognosis depends on severity
How does IgA glomerulonephritis appear?
IgA deposition in mesangium
What causes membranoproliferative glomerulonephritis?
Idiopathic = type 2 hypersensitivity (infection, SLE, cancer), affects adults and children, either nephrotic or nephritic syndrome, prognosis depends on severity
What is the appearance of membranoproliferative glomerulonephritis?
Big lobulated hypercellular glomeruli with thick membranes = train track appearance
What conditions can diabetes cause in the kidneys?
Diffuse and nodular glomerulosclerosis
Nodules = Kimmel Stiel Wilson lesions
Arterial sclerosis
What infections can diabetes cause in the kidneys?
Pyelonephritis, papillary necrosis
Why is it difficult to tell cystic disease from cancer?
Many early cancers are cystic or partly cystic so is difficult to differentiate = use Bosniak score to predict cancer
What are some features of acquired cysts?
Very common = seen frequently at autopsy
Often associated with long term dialysis
Simple cysts = attenuated lining, degenerative change
What causes autosomal dominant polycystic kidney disease (ADPCKD)?
Uncommon = due to mutation in nephrin
Often secondary changes = haemorrhage, infarction, rupture
What occurs in autosomal dominant polycystic kidney disease?
Lots of cysts develop over time = kidney becomes huge
Cysts are lined by simple epithelium
How does autosomal dominant polycystic kidney disease present?
Mass like lesion or pain/haematuria due to secondary changes
What are the systemic manifestations of autosomal dominant polycystic kidney disease?
Liver cysts and cerebral aneurysms = associated with sub-arachnoid haemorrhages
What are the features of autosomal recessive polycystic kidney disease?
Several subtypes = all occur in childhood
Kidney of normal size and has smooth surface
Causes liver cysts
What is the only benign tumour of the kidney?
Oncocytoma
What are the malignant tumours of the kidney?
Chromophobe, clear cell, papillary, collecting duct
What tumour of the kidney occurs in the paediatric age group?
Wilm’s tumour
How do oncocytomas appear?
Small, oval and well circumscribed
Mahogany brown with central stellate scar
Very pink with granular cytoplasm on histology
What are some features of papillary malignancy?
Second most common, low grade (type 1 and 2), finger like projections
What are chromophobe malignancies difficult to distinguish from?
Papillary malignancies = same histology but chromophobe has raisonoid nuclei and perinuclear haloes
Are chromophobe malignancies common?
No
What are some features of collecting duct carcinomas?
Least common, high grade appearance with very desmoplastic stroma, poor survival
What malignancy do most people mean when they speak of renal cancers?
Clear cell carcinomas
What are the risk factors for clear cell carcinomas?
Strong link to obesity, genetic influence
What is the presenting complaint of clear cell carcinomas?
Haematuria, mass, rarely hypertension
What is the macroscopic appearance of clear cell carcinoma?
Often partly cystic and very heterogenous surface = most striking feature is bright yellow tumour surface
What is the microscopic appearance of clear cell carcinomas?
Clear cells = artefact of processing and relate to cell hypoxia
How is clear cell carcinoma staged?
Size and then invasion of other structures
What structures do clear cell carcinomas tend to invade?
Propensity of renal vein involvement
Can even extend into vena cava and grow up towards heart
What is VHL associated with?
Responsible for most sporadic renal cancers = codes for hypoxia inducible factor (HIF)
How do VHL and HIF interact normally?
VHL ubiquinates HIF = in low 02 they dissociate and HIF acts as a transcription factor for VGEF, PDGFRB and EPO
What pathologies make up VHL syndrome?
Renal cell carcinoma Cerebellar haemangioblastoma Pancreatic serous cystadenoma Tumours of the endolymphatic sac Epididymal serous cystadenomas
What is xanthogranulomatous pyelonephritis?
Specific infection that creates a mass in the kidneys
