Patho E3: renal

Signs of early stage renal disease

oliguria or composition

Signs of late stage renal disease

edema, fluid overload, electrolyte

Serious damage occurs when how many nephrons are damaged?

75-90%

What does the GFR have to be dx renal failure?

< 60

What is the role of mesangial cells?

contracts & relaxes in response to vasoactive substances → regulates GFR

Which hormones influence the CCD?

Aldosterone, ADH

What is the role of Aldosterone & Angio II?

stimulate resorption of Na & H2O → inc BP

What is the role of ANP & urodilatin?

inhibit reabsorption → dec BP

What do the P (principal) cells respond to?

ADH

What does ADH and Aldosterone tell P cells to do?

reabsorb H2O through aquaporin channels & inc Na reabsorption

What do I (intercalated) cells do?

regulate acid secretion

What do Alpha i cells do?

secrete H+/reabsorb HCO3

What do Beta i cells do?

secrete HCO3/reabsorb H+

What is a nephrotic disorder?

glomerular problem → proteinuria w/o inflammation

What is a nephritic disorder?

glomerular problem→ variable proteinuria w/ RBCs or WBCs in urine

What causes prerenal failure?

decreased renal perfusion, not enough blood to kidneys

ex: hypovolemia, dehyrdation

What causes intra renal failure?

damage to the nephron

Ex: glomerulonephritis

What causes post renal failure?

obstruction in the collecting system

ex: kidney stone

What is azotemia?

inc in the blood urea nitrogen (BUN)

What is the most common cause of intra renal failure?

Acute tubular necrosis (ATN)

Ex: multiple myeloma, pyelonephritis

What determines glomerular filtration?

afferent & efferent arteries

What can cause ARF in pts that are dependent on prostaglandin-mediated vasodilation to maintain renal perfusion?

NSAIDS

What can cause ARF in pts with renal hypoperfusion that are dependent on Angio II to maintain pressure?

ACE inhibitors

What drug shouldn’t you give to pts with kidney disease?

ACE inhibitors

What makes up the majority of acquired ARF cases?

prerenal causes

What are signs of prerenal ARF?

azotemia, oliguria

What can cause intrinsic renal failure?

glomerular disease, tubular injury, interstitial nephritis, vascular disease

What causes acute tubular necrosis?

drugs, ischemia, infection

What are signs of post renal failure?

oliguria or anuria if obstruction is bilateral

How can you reverse post renal failure?

remove obstruction

What is the tubular theory of ATN development?

sloughing cells get stuck → cast → clog tube → ischemia

What is the vascular theory of ATN development?

dec perfusion via afferent or efferent → dec GFR

What symptoms seen later in renal failure are caused by the loss of renal water and Na excretory capacity?

dyspnea, orthopnea, rales, 3rd hear sound, peripheral edema

*mimic S/sx of LVHF

In severe renal failure, what causes altered mental status?

toxic effect of uremia (elevated levels of nitrogenous wastes and fixed acids)

What lab changes are seen in ARF?

inc BUN/Cr, serum electrolytes, PO4

dec serum Ca, EPO

What changes in the urine are seen in ARF?

granular & epithelial cell casts, WBCs, proteinuria, dec urine osmolarity

What are the 3 phases of ARF?

oliguric, diuretic, convalescent

Which phase of ARF lasts 1-2 weeks and is characterized by dec urine output?

oliguric phase

Which phase of ARF lasts 2 days- 2 weeks and is characterized by inc urination?

diuretic phase

Which phase of ARF lasts 8 days- 1 yr marking recovery, but has an inc likelihood of another case of ARF?

convalescent phase

What classifies CRF?

GFR < 60 × 3+ mo

Is it possible to reverse CRF?

no

What is needed to treat ESRD?

dialysis, transplantation

What are the top causes of CRF?

DM (#1), HTN (#2)

What is the pathophysiology behind CRF?

irreversible loss of nephrons → inc functional burden → inc glomerular filtration pressure & hyperfiltration (same amount of blood less space to filter) → scaring and fibrosis (glomerular sclerosis) → inc nephron destruction → inc uremia

What are the affects of the destruction of glomeruli?

body growth arrest, HTN, anemia

What causes uremia?

toxic effects of nitrogenous wastes, inc amounts of hormones, loss of normal substances (EPO)

What are signs of CRF?

Na+ & water excess, hyperkalemia, disorder of Ca2+ & PO4, cardiopulmonary problems, anemia, peripheral neuropathy, uremic frost

What type of anemia would CRF cause?

normochromic, normocytic

ESRD severely increases risk of what?

CV risk -leading cause of mortality

When pts are on dialysis does their BUN matter?

nope

What is PKD?

inherited disease (auto dominant) characterized by multiple cysts in the renal parenchyma

What genetic defect causes PKD?

defect in PKD1 and PKD2 on chromosome 16

Which form of PKD is dx in infants & young children and has a high rate of neonatal death?

Autosomal Recessive PKD

Which form of PKD is dx in adulthood and declines progressively over 10-20 yrs?

Autosomal Dominant PKD

What is common in pts with ADPKD and often precedes renal dysfunction?

HTN

What S/Sx of ADPKD usually begin btwn 40-50 y/o?

UTI, Abd discomfort, back/flank pain, hematuria, HTN

What type of bacteria most commonly infects kidney cysts?

G-

What systemic problems can ADPKD cause?

cerebral aneurysms, aortic root dilation, cardiac valvular abnormalities, hepatic cysts, hernias

What is acute glomerulonephritis?

inflammatory type of nephritic syndrome often occurring in association w/ infection, typically abrupt onset

What causes acute glomerulonephritis?

antigen-antibody complexes from recent infxns

What is the pathophysiology of acute glomerulonephritis?

activated inflammatory cells → ag-Ab complexes → deposit in membranes → more permeable → angio contracts mesangial cells → dec GFR → fluid retention→ RBCs pass into glomerulus → hematuria

What S/sx are associated w/ acute glomerulonephritis?

gross hematuria, WBC cast, proteinuria, periorbital edema, LE edema, ascites, pleural effusion, HTN, inc CO, inc PVR

What is rapidly progressive glomerulonephritis?

group of disorders that display features associated w/ vasculitis, kidney fxn lost within wks-months, uncommon

What are the 4 categories of RPGN?

complication of acute/subacute infection, complication of a multi-system disease, drug exposure, idiopathic

What two infections are most associated w/ glomerulonephritis?

strep & infective endocarditis

What is the pathophysiology behind RPGN?

fibrin → glomerular crescent formation → deterioration of renal fxn; severity is related to the degree of crescent formation

What is the pathophysiology behind chronic glomerulonephritis?

ag-Ab complexes → cellular proliferation → deterioration of renal fxn → HTN, scarred kidneys, renal failure

What is chronic glomerulonephritis?

continuing or persistent hematuria & proteinuria → slowly progressive deterioration in renal function

What S/sx are associated w/ chronic glomerulonephritis?

hematuria, proteinuria, scarring → dec renal fxn, edema, HTN

What is nephrotic syndrome?

collection of sx caused by glomerular disease associated w loss of large amounts of protein in the urine from inc permeability

How much protein is lost in the urine in pts with nephrotic syndrome?

>3.5 g/day

What S/sx are associated w/ nephrotic syndrome?

edema, hypoalbuminemia, HLD, lipiduria, frothy/foamy urine, hyper-coagulability, alter immunity

How does nephrotic syndrome resolve?

typically spontaneously

What disorder is related to nephrotic syndrome in pediatric pts?

minimal change disease

What is the pathophysiology of nephrotic syndrome?

permeability inc → dec onc pressure → inc hydro pressure and third spacing of fluid → RAAS → Na & H2O retention → more protein loss & edema

What S/sx are associated with renal stones?

flank pain (may radiate to groin) (related to the degree of distention), hematuria, oliguria/anuria

What are major complications that renal stones can cause?

hydronephrosis, permanent damage, infection, abscess, HTN

What makes up a majority of renal stones?

Ca

What causes most renal stones?

hypercalciuria, hyperuricosuria, hyperparathyroidism

What are struvite stones?

made of mag, ammonium, phosphate salts due to chronic UTI by urease-producing organisms

What is the pathophysiology behind renal stones?

dehydration, high-protein diet, high Na diet: all affect Ca excretion → Ca oxalate stone formation