Renal Diseases Flashcards
Arterionephrosclerosis
scarring/luminal narrowing in afferent arteriole that causes ischemia of the nephron, resulting in global glomerular sclerosis
IgA Nephropathy
aka Berger disease. Underglycosylated IgA (from genetic defect) is made during course of an infection; IgA is able to get from circulation out into the mesangium (because it's not as negatively charged as it should be); phagocytosis of IgA by podocytes activates the podocytes and they produce more ECM, thickening the mesangial matrix.
Goodpasture syndrome
Antibodies are formed against GBM and are deposited in the subendothelium. They circulate before being deposited so they can be removed via plasmapharesis.
Membranous nephropathy
Either antibodies attack antigens in podocytes (PLA2R or NEP), or cationic ICs deposit in subendothelial space.
This leads to thickening of GBM: spike and dome and granular on IF. Treatment depends on degree of proteinuria - 4g control BP and use cytotoxic agents (CIs)
Post-streptococcal/infectious glomerulonephritis (PIGN)
antibodies formed against exotoxin B from strep pyogenes (~1-3wks post-skin/throat infection) are then deposited on antigens that are planted in the basement membrane; forms subepithelial humps, lumpy-bumpy granular appearing deposits on IF stain, and NT infiltration/hypercellularity; treatment - control HTN and treat infection
Metabolic/diabetic glomerular injury
glycosylation of GBM proteins and plasma proteins that get deposited in the GBM damages it; some glycosylations are metabolized to “Advanced Glycated End-products”, or AGE which leads to accelerated aging of organs. Will also get NADPH oxidase activation (by advanced oxidation protein products (AOPPs), RAAS, TGF-beta, and ROS) which leads to mesangial activation/matrix production and podocyte injury/apoptosis, and proteinuria. Start with sclerosis of efferent, raise GFR –> hyper filtration, microalbuminemia at first, then continued damage. Treat with ACEi’s.
Membranoproliferative glomerulonephritis
membrano = GBM expansion proliferative = hypercellular (proliferating native glomerulus cells as well as inflammatory infiltration) glomerulonephritis = inflammation of the glomerulus
Malignant Hypertension
hypertension that causes end-organ damage - from thickening of the artery intima and basement membrane, ultimately cutting off blood supply to the downstream organ tissue
Nephrotic syndrome
glomerular disease that leaks protein; consists of 3 features:
- thicker basal lamina but functionally leaky
- hypoalbuminemia - because it’s escaping through the leaky GBM
- low oncotic pressure - results in edema
Focal Segmental Glomerulosclerosis (FSGS)
damaged adhesion proteins in podocytes degenerate, maybe due to sUPA-R, familial mutations in adhesion proteins (alpha-actinin-4, podocin, TRPC6), or drugs, infection (HIV/PVV), and nephron loss; highly associated with ApoL1 mutation; will see hyalinosis, perhaps adhesion to Bowman’s and glomerular collapse.
Treat with GC and control HTN/HLD.
Minimal Change Disease (MCD)
suspected: T cells make a circulating factor (not an Ab because IF is negative) that causes podocyte damage and highly selective proteinuria (albuminuria); may be 2/2 Hodgkin’s lymphoma or drugs. Treatment with HTN/HLD control, tx primary disease; usually great response to GCs
Cryoglobulinemia
IGs, complement, and RF precipitate at cold temperatures and cause clinical sx of hyperviscosity and/or thrombosis; ICs deposit in endothelial, subendothelial, and mesangial layers–causing MPGN; treat underlying cause (Hep C, HIV, AI disease, MM, etc.)
HIV-associated nephropathy (HIVAN)
direct infection of podocytes by HIV (G1/2 ApoL1 mutation more susceptible); collapsing glomeruli with FSGS, microcystic tubular dilation, interstitial inflammation/fibrosis, and podocyte proliferation; can treat/reduce with anti-virals
Light Chain Disease (LCD)
non-amyloid monoclonal IG deposition/precipitation often associated with MM or other lymphoproliferative disease; causes nephrotic syndrome or RP-TIN; will see glomerulosclerosis with mesangial expansion. Congo red negative without fibrils.
Amyloidosis in kidney
deposition of mis-folded fibril proteins in the vessel wall, then interstitium, eventually organ infarction; non-proliferative, non-inflammatory glomerulopathy; tubular atrophy and interstitial fibrosis; “apple-green” on Congo red stain under polarized light; can treat with low dose melphalan and dexamethasone (AL)
eprodisate (AA)
Sickle cell nephropathy
vaso-occlusion of glomerulus, peritubular capillaries → infarction/necrosis, hemorrhage, glom. hyperfiltration, patient will have SCD, glomerular HTY and mesangial expansion, segmental sclerosis
Hereditary Renal Glycosuria
LOF mutation in SGLT2 (PT) that reduces glucose reabsorption, resulting in mild-moderate glycosuria. Can functionally occur when SGLT2 is saturated by the large amount of glucose, such as in diabetes.
Cystinuria
LOF mutation of (PT) amino acid transporter, normally reabsorbs cystine, ornithine, lysine, and arginine; can lead to cystine stones (hexagons)
Defective Phosphate reabsorption
normally: PHEX inhibits FGF-23 which inhibits P reabsorption.
1. LOF in FGF-23 or GOF in PHEX: too much P reabsorption; hyperphosphatemia
2. GOF in FGF-23 or LOF in PHEX: too much inhibition of P reabsorption; hypophosphatemia (rickets)
X-linked hypophosphatemia
LOF in PHEX
think pheX = X-linked
AD hypophosphatemic rickets
GOF in FGF-23
AR hypophosphatemic rickets
several mutations that add up to too much FGF-23, OR defect in Na/P co-transporter
Oncogenic hypophosphatemic Osteomalacia
increased FGF-23 production by some tumors
Osteomalacia
softening of the bones - when you have too little phosphorous (as in rickets or FGF-23 overproduction) then you reduce PTH (because PTH decreases P reabsorption) which prevents Ca reabsorption; softens bones
*this condition is called rickets in children
Hartnup disease
SLC 6A19 defect - transporter for neutral amino acids; symptoms are failure to thrive, photosensitivity, intermittent ataxia, nystagmus, tremor
Vitamin D dependent rickets - type I
defect in 1-alpha-hydroxylase (PT) preventing VitD activation; results in hypophosphatemia