Renal Pathology - Glomerular Disease Flashcards
What 3 structures make up the urine filtration barrier? What else is present in the glomerulus?
- endothelial cells of the glomerular capillaries
- basement membrane of the glomerular capillaries
- visceral epithelium (podocytes)
(filters blood and forms primary urine)
mesangial cells, mesangial matrix, parietal cells, Bowman’s capsule
What affects glomerular filtration? What is the primary function of the glomeruli?
size and electrical charge - water, particles <3.5 nm, potassium, sodium, glucose
maintains ionic and osmotic homeostasis in the blood
(glomerular damage = problems with filtration)
What 2 molecules are typically not filtered and remain in the blood?
- albumin
- antithrombin III
(may be leaked in the urine with glomerular disease)
What are 3 indications of glomerular injury?
- proteinuria - presence of abnormal quantities of protein in urine
- albuminuria —> edema
- loss of antithrombin III —> thrombi formation
Tubular injury can also result in proteinuria. How does this compare to glomerular disease?
only small molecules will be leaked into urine - aminoaciduria, glucosuria
What are the major results of albuminuria due to glomerular disease?
- ascites
- hydrothorax/hydropericardium
What is the result of antithrombin III loss in urine due to glomerular disease?
hypercoagulable state —> thrombi formation common in the lungs and pulmonary artery
What are the 3 hallmarks of glomerular disease?
- proteinuria
- hypercoagulable state due to the loss of antithrombin III
- nephrotic syndrome - severe proteinuria + severe hypoalbuminemia + generalized edema + hypercoagulable state + hyperlipidemia
What causes hyperlipidemia in nephrotic syndrome?
liver tries to compensate and produce more albumin, which causes it to also produce cholesterol
What is the difference between glomerulitis and glomerulonephritis?
GLOMERLITIS: inflammation restricted to glomerulus caused by acute septicemia (glomerulus is the first to receive blood!)
*GLOMERULONEPHRITIS: usually of immune origin including glomerular disease and secondary tubulointerstitial and vascular changes
What is the difference between proliferative and membranous glomerulonephritis?
PROLIFERATIVE: proliferation of endotheliuml/podocytes/mesangial cells along with inflammatory cells
MEMBRANOUS: thickening of the basement membrane/mesangial membrane
What is a common cause of glomerulitis in foals? How does this cause disease?
Actinobacillus equuli —> suppurative glomerulitis
bacteria enter the kidney via vasculature and lodge in the capillaries of glomeruli, where they replicate and induce necrosis and inflammation (AKA embolic glomerulitis)
What is the cause of glomerulonephritis? What are specific causes in dogs and cats?
immune-mediated —> Ag-Ab complex deposition and complement activation often associated with persistent infections or diseases that have prolonged antigenemia
DOGS: pyometra, pyoderma, chronic parasitism (Dirofilaria), autoimmune disease (SLE), neoplasia
CATS: FeLV, FIV, FIP
What are the 2 mechanisms of immune-mediated glomerulonephritis?
- preformed circulating Ag-Ab compexes associated with persistent infections/disease —> prolonged antigenemia —> formation of soluble immune complexes
- antigen is trapped in glomerular capillary wall and circulating antibodies form complexes with them
What are the 4 main locations of immune complexes causing glomerulonephritis?
- mesangial - within the mesangial matrix
- intramembranous - in the BM of the glomerular basement membrane
- subepithelial - between feet of podocytes
- subendothelial - below endothelium of glomerular capillaries