Renal Patho

Medulla

Inner portion of kidney. made of renal pyramids and tubular structures

renal pyramid

channels output to renal pelvis for excretion

renal calyx

channels formed urine from the renal pyramids to the pelvis

Renal vein

99% of filtered blood is circultaed thru the renal vein. the other 1% has waste products and undergoes procesing

renal pelvis

blood containing waste products forms urine and is channeled away

afferent arteriole

carries blood to the glomerulus

efferent arteriole

carries blood away from the glomerulus

medullary nephrons

deeper loop of Henhle but gets damaged more easily

cortical nephrons

more shallow

glomerulus

network of capillaries, acts as a filter for the passage of protein and RBC free filtrate

Bowman's capsule

contains glomerulus, acts as a filter for urine

PCT (proximal convoluted tubule)

reabsorption of glucose, amino acids, metabolites, and electrolytes from filtrate. reabsorbed substances go into circulation again

Loop of Henle

U shape, located in medulla, extends from the PCT and DCT, further concentration of filtrate thru reabsorption

DCT (distal convoluted tubule)

where filtrate enters the collecting tubule

collecting tubule

releases urine

Pressure at glomerulus

vascular pressure= hydrostatic pressure --> so, no filtration is happening

ureters

bring urine from kidney to bladder

Basic kindey functions

water, elyte, acid-base homeostasis, extretion of metabolism waste products (aura, uric acid, creatinine), detoxifying drugs, regulation of BP and ECF (RAAS and ADH), erythropoietin, calcium and phosphate metabolism, activation of vitamin d, excretion of phosphate, catabolism of hormones (insulin, glucagon, parathyroid hormone, calcitonin, GH

Na+ Normal Values and Renal Failure values

135-145

rf: nL or lower

Cl- Normal Values and Renal Failure values

95-105

RF: nL or lower

K+ Normal Values and Renal Failure values

3.5 - 5.5

RF: nL or increase

CO2 Normal Values and Renal Failure values

25-28

RF: low

Ca2+ Normal Values and Renal Failure values

8.5-10.5

RF: lower

Phosphorus Normal Values and Renal Failure values

3-5

RF: increase

ABGs in RF

decreased arterial pH and bicarb levels, metabolic acidosis

BUN Normal Values and Renal Failure values

10-38,

increase in dehydration, GI bleeding, renal failure, poor indicator of RF

Creatinine

increase only caused by rf,

not absorbed or secreted by the tubules, dependent on renal clearance, body muscle mass, and sex, not sufficient by itself for measuring renal function

BUN: Creatinine ratio

normally is 10:1, RF is over 20:1

azotemia

azotemia

accumulation of nitrogenous wastes in the blood (urea, creatinine, others)

Creatinine clearance

volume of blood in mL that the kidneys can clear of creatinine in one minute. most accurate measure of GFFR because creatinine is filtered by the glomeruli and not reabsorbed by the tubules

GOLD STANDARD FOR RENAL FUNCTION

GFR

rate at which the glomerlui filter blood, about 120mL/minute

GFR is a function of

permeability of the capillary walls, vascular pressure, filtration pressure

GFR and creatine clearance

since the tubules don't secrete or reabsorb creatinine, GFR=Creatinine clearance

Normal female range creatinine clearance

0.8-1.5 gm/24 hrs

Normal male range creatinine clearance

1-2 gm/24 hrs

Male GFR estimate

(140 - age) x (weight in kg)

---------------------------------

(72 x serum creatinine in mg/dL)

Female GFR estimate

male calculation times 0.85

CC equation

GFR+(quantity of urine) x (creat conc in urine)]

--------------------------------

(serum creat)

CBC in Rf

low RBC, low H and H, microcytic hypochromic anemia

Proteins in blood

albumin and globulins, reflects protein intake, primary function of plasma proteins is to hold fluid in vascular space

kidney failure is _______ and _________

progressive and irreversible

When renal function is above %0%

Clinical manifestations are minimal as surviving nephrons take over the work of those lost

patho of chronic renal failure

surviivng nephrons increase rate of filtartion--> hypertrophy. more nephrons die andthe remaining and difficulty handing the demand --> damage and death of remaining nephrons--> scar tissue --> renal blood flow reduced. release of renin --> fluid overload and HTN --> HTN accelerates renal failure

How does HTN accelerate renal failure

Increases filtration & demand for reabsorption of plasma proteins (workload)

Reduced renal reserve

GFR is 35-50% of normal, BUN and creatinine normal, no s/s

Renal insufficiency

GFR= 20-35% of normal, azotemia, anemia, HTN. initial s/s are isosthenuria, polyuria isotonic with plasma

Renal failure

GFR 20-25% of normal, kidneys can't regulate volume and solute composition --> decreased urine output --> edema, metabolic acidosis, hypercalcemia. overt uremia --> neurologic, GI, CV complications

ESRD

GRF less tha 5%, atrophy and fibrosis in glomeruli and tubules, dialysis or transplant necessary for survival

K+ levels in people getting dialysis

should be normal.

Uremic Syndrome

extra area in the blood because the kidneys can't filter it out, uremic frost, inflamed pleura, uremic pericarditis, itching, bone pain, acidosis which effects the nausea center of the brain causing vomit, weak and brittle nails

RF alterations in body fluid

changes in tubular functions, can't make ammonia, inability to excrete bicarb, potassium, sodium, phosphate, cant activate vitamin D

Effects on Altered Body Fluids in RF

Fixed urine SG, metabolic acidosis, hyperkalemia, hypernatremia, hyperphospatemia, hypocalcemia, increased levels of PTH

Hematologic effects of RF

Impaired synthesis of erythropoietin and effects of uremia, impaired platelet function

Manifestations of hematologic effects of RF

anemia and bleeding tendencies

Anemia in CFR

Shortened lifespan of RBCs d/t toxic serum, decreased production or erythropoietin, bleeding from cogulation defects, anticoagulation during dialysis can lead to heavy menstrual bleeding and GI bleeding, decreased immune system --> susceptible to infection

Tx for anemia

Epogen--> synthetic erythropoeitn, dialysis, transfusions, cheleaton to remove excess fe and K

CV changes in RF

activation of RAA--> increased BV., fluid retention and hypoalbuminemia, increase metabolic waste

Manifestaions of the CV changes

HTN, edema, CHF, pulmonary edema, uremic pericarditis

HTN r/t RF

caused by fluid overload and RAAS. causes hypertensive encephalopathy (increased ICP, headache, retinal changes, seizure, coma, CVA)

RAAS

renal ischema --> RAA activation --> vasoconstriction --> HTN --> LVH --> CVA

Myocardium effects

Uremia causes dysrthymias. calcium and phosphate cause calcification of coronary arteries.

Hyperkalemia effects

V-fib, prolonged P-R, widened QRS, peaked t waves

GI effects

increased metabolic waste, decreased platelet function and gastric acid secretion d/t hyperparathyroidism.

Leads to anorexia, n/v, GI bleed

Uremic encephalopathy

lethargy, decreased alertness, seizure, asterixis- twitching tremors.

neuropathy

effect of fluid and electrolyte imbalance and excess waste

restless leg syndrome, paresthesias, muscle weakness, paralysis

Peripheral neurpathy

changes are symmetric and begin distally, gait changes, burning feet, restless legs, foot drop

Abnormal EEG

Indicitive of metabolic encephalopathy

High bone turnover (osteitis fibrosa)

high phosphate and low vitamin d decrease calcium levels which stimulates PTH to break down the bone in an attempt to extract calcium, bone remodeling is done improperly then because it has to be done so fast

Low bone turnover (osteomalacia)

Soft, poorly mineralized bones due to impaired bone mineralization.

Causes:

Vitamin D deficiency

Aluminum toxicity (especially in chronic kidney disease)

Low calcium or phosphate levels

Key feature: Normal bone formation, but bones remain soft and weak because they are not mineralized properly

Renal Osteodystrophy

Osteomalacia --> calcium and phosphate sit in the cardiovascular tissue, liver, joint tissue --> fractures and bone problems --> red eyes

Renal Osteodystrophy Tx

Vitamin D therapy (DHT or calcitrol), parathyroidectomy if hyperplasia occurs and they start functioning autonomically, calcium acetate or carbonate (Pholso or tums)