B4.042 - Renal Failure due to Hypertension Flashcards
what is high blood pressure
resting blood pressure persistently above 130-140/90
epidemiology of hypertension
Age Male gender African American Obesity High Na intake Low K intake Genetic predisposition Excess alcohol
what is prehypertension
120/80 - 139/89
what is stage 1 HTN
140/90 - 159/99
what is stage 2 HTN
= or > 160/100
what is early stage HTN due to
young patients high cardiac output - normal TPR
what is adult stage HTN
>40 yo High TPR normal or below normal CO
what is late stage HTN
high peripheral resistance, LVH, maybe low CO
what is primary HTN
no underlying cause and is a diagnosis of exclusion
what does primary HTN result from
a complex interaction of genetic and environmental factors (high Na intake; lack of exercise, obesity, depression)
secondary HTN causes
Renal parenchymal disease Reno-vascular disease Endocrinology disease Cardiac Disease Drugs
what are some renal parenchymal diseases that can cause secondary HTN
Glomerulonephritis Chronic renal failure Polycystic kidney disease Liddles syndrome Familial Hyperaldosteronism
what are reno-vascular diseases than can cause secondary HTN
Renal arterial stenosis (athoerosclerosis) Fibromuscular dysplasia
what are endocrinology diseases that can cause secondary HTN
pheocromocytoma and neuroblastoma corticosteroid excess congenital adrenal hyperplasia thyroid disorders
what are cardiac diseases than can cause secondary HTN
coarctation of aorta
what are drugs that can cause secondary HTN
cocaine amphetamines epinephrine phenylephrine
what are large artery pathologies than can cause HTN
accelerated atherosclerosis elastic hyperplasia aneurisms all lead to decreased compliance and palpable rigidity of artery
what are pathologies of the small arteries caused by HTN
Hypertrophy of smooth muscle
elastic laminal enlargement
hyaline sclerosis growth of the intima
all lead to obstruction of flow, weakness/absence of pulses
what are pathologies of the heart from HTN
LVH
left ventricular failure
Diastolic dysfunction
lead to 4th heart sound, ECG with increased QRS, signs of hypertrophy/insufficiency
what are pathologies of the brain due to HTN
atherosclerosis
little aneurisms predisposition to stroke can lead to transient ischemic attacks. stroke
what are pathologies of the retina due to HTN
atherosclerosis
aterial wall thickening
hemorrhage
arteriolar spasm
edema of retina and optic nerve lead to blurry vision
what is hypertensive kidney disease
damage of the kidney due to chronic HTN
how is CKD noted initially
initially CKD goes without symptoms and only detected by increased serum creatinine or proteinuria. Eventually leads to renal insufficiency.
GFR characteristics of CKD, who gets it?
GFR < 60 mL/min/m2 1:8 adult americans have CKD 24.5% of 60 year olds or older have CKD
symptoms of CKD
loss of appetite, nausea, vomiting, weight loss, fatigue sleepiness, changes in urine output, itching, weight loss
what are signs of CKD
HTN, peripheral edema, shortness of breath, chest pain, GFR increase, increased creatinine and BUN
what is this indicative of
narrowing of arteriolar lumen
thickening and hyalinazation of the walls
seen in nephrosclerosis
what is shown here
medial hypertrophy
reduplication of elastic lamina
growth of intima
what is shown here
glomeruli
areas of thrombosis and necrosis
hemorrhages of parenchyma
what is shown here
tubules
patchy ischemic atrophy
interstitial fibrosis
describe the pathophysiology of hypertension and kidney disease
HTN –> vessel damage, slerosis/reduced lumen –> increased intraglomerular pressure –> glomerular damage (podocyte injury) –> microalbuminuria proteinuria –> decreased perfusion –> GFR initially maintained –> glomerular damage, edothelial cell proliferation, messangial cells proliferation –> renin angiotensin-aldosterone system –> increased sympathetic n. activity –> decreased renal blood flow –> increased tubular Na reapsorption –> decreased GFR Renal insufficiency
what is Kuf
ultrfiltration constant
reflects teh net filtration pressures, surface area and permeability of the glomerular membrane
describe pressures in renal circulation that are altered in HTN
oncotic pressure stays constant
Hydrostatic pressure starts out high in the renal arteries and afferent arterioles, then drops in glomerular capillary, drops more drastically in efferent arterioles and then slowly drops more through peritubular capillaries, intrarenal vein and the renal vein
what is ultrafiltrate
plasma without proteins
only ions and small molecules filter
describe glomerular membrane selective permeability
only things smaller than albumin can pass through
filtration favors cationic molecules compared to anionic ones
In HTN damage of glomerular membrane allows passage of proteins
describe the function of glomerular mesangial cells
provide structural support for the glomerular capillaries
regulate glomerular filtration via their contractile capacity
function as phagocytes
secrete paracrine substances
what stimulates the renin angiotensin aldosterone system
increased sympathetic n activity
decreased renal blood perfusion
decreased Na delivery to macula densa
what does renin do
stimunates angiotensinogen to be converted to angiotensin 1
what does angiotensin II do
inhibits renin
vasoconstricts
Na retention
Na reabsorption in proximal tubules
what happens in CKD when GFR is reduced
clearance of creatinine and urea is reduced
Urea leads to azotemia uremia causing lethargy, pericarditis and ecephalopathy
potassium accumulates in blood producing heart problems
what are the stages of chronic renal disease based on GFR estimates
what are important indicators of glomerular nd tubular function
BUN/Creatinine ration (BUN/Cr)
what information does creatinine tell you
its mainly filtered and little is secreted so gives you info on glomerular function
what information does urea (resonsible for BUN) tell you
its filtereed and reabsorbed in the tubules, so it gives an estimate of GFR but also tubular function
what is a normal BUN/Cr and what does a high BUN/Cr or low BUN/Cr indicate
normal is 15
if BUN/Cr > 15 glomeruli more affected
if BUN/Cr <15 tubules more affected
what causes volume overload due to CDK
decreased glomerular function, GFR
High Cr, uremia
olguria
Electrolyte imbalance (less K secretion, hyperphosphatemia
Na retention
Leads to peripheral edema, pulmonary edema, HTN
what causes HTN in CKD
Increased intravascular volume
Na retention
Alteration of kidney reg mechanisms controlling ECF volume and osmolarity
Renin agniotensin Aldosterone
what causes acidosis in CKD
lack of acid secretion
what caues anemia in CKD
kidneys cant make EPO
altered oxygen sensing mechanism in kidney
leads to:
decreased delivery of oxygen to tissues
increased CO
ventricular hypertrophy
CHF
Impaired host defense against infection
growth retardatio in kids
how does bone disease become a consequence of CKD
GFR declines as a result of underlying renal disease
This leads to less inorganic phosphage excretion
Decreased serum calcium and calcitrol stimulate PTH production
Phosphate retention also stimulates PTH secreation
Metabolic acidosis affects bone
treatment of CKD
- treat HTN early on
- Na restriction
- diuretics
- ACE Inhibitors
- Ca blockers
- potassium binders to preven hyperkalemia
- dyalissi with vitamin D eventually and EPO replacement
