Patho Exam 1 Review

intracellular fluid

2/3rds of bodily water, contains large amounts of potassium

Extracellular fluid

1/3rds of bodily water, contains large amounts of sodium and chloride

What do serum blood tests measure?

ECF Values

What makes up ECF?

Plasma (5%)

Interstitial fluid (14%)

Transcellular (1%)

ICF is regulated by

proteins

Diffusion

Movement of proteins along a concentration gradient from a higher to lower concentration

osmosis

Movement of water across a semipermeable membrane down a concentration gradient from an area with less particles to an area with more

osmotic pressure

pressure generated as water moves across the semipermeable membrane

Osmolality

osmolar concentration in 1kg of water

normal osmolality value

275-295 mOsm/kg

tonicity

tension that the effective osmotic pressure of a solution with impermeable solutes exert on cell size because of osmosis

Isotonic

ECF has same osmolality as ICF; cells neither shrink or swell

Hypertonic

ECF has higher osmolality than ICF; water leaves ICF to ECF and cells shrink

Hypotonic

ECF has lower osmolality than ICF, water moves from ECF to ICF and cells swell

Capillary fluid exchange

Movement of fluids, gasses, and waste between blood and body tissues

Hydrostatic pressure

Pushing pressure; controlled by pressure within the capillary walls

Capillary filtration pressure

pushes water out of capillary into interstitial spaces

Interstitial Hydrostatic pressure

Opposes movement of water out of capillary

Osmotic pressure

pulling pressure; Controlled by substances in the blood

Capillary colloidal osmotic pressure

pulls water back into capillary

tissue colloidal osmotic pressure

pulls water out of capillary into interstitial spaces

Anasarca

Generalized edema; a result of increased vascular volume

Increased capillary filtration pressure (related to edema)

Capillary distention (stretching) occurs due to increased vascular volume, leading to fluid build up in dependent parts of the body (dependent edema)

edema

swelling caused by fluid build up

Decreased capillary colloidal osmotic pressure (related to edema)

Decreased plasma proteins and sal pulling fluid into capillary, can result in inadequate protein production or abnormal loss of protein

Most common site of plasma protein loss

The kidneys (even though they’re not supposed to be lost)

What does damage to the capillary wall lead to?

Increased capillary permeability, leading to plasma proteins leaking into interstitial spaces, increases colloidal osmotic pressure

lymphedema

lymph systems cannot remove and return excess fluid volumes

organs where edema may be life-threating

brain, larynx, or lungs

Non-threatening edema

Joints, can lead to decreased QoL

Body water balance

Fat has much less water than skeletal muscle; all healthy people require approximately 1mL of water to metabolize 1 calorie

Blood pressure relating to perfusion

pressure is needed in our system to perfuse (deliver blood to) organs and cells

Mechanism of fluid regulation

Constricted vessel and no change in fluid volume lead to increased pressure

Dilated vessel and no change in volume lead to increased pressure

Regulatory mechanisms relating to age

Decrease with age

When osmolality goes up

thirst

Two stimuli related to thirst

Cellular dehydration (caused by ECF osmolality increase), decrease in bp

how much cardiac output do kidneys require?

20-25%

What do the renals regulate?

Vitamin D and calcium levels

Nephrons related to age

Lose ~10% each decade after 40

What do the nephrons contain?

Glomerulus, proximal and distal convoluted tubules, loop of henle, and collecting duct

Glomerulus

site of filtration

Layers:

Capillary endothelial

Basement membrane (selective permeability)

Single celled epthelial layer

Urine

pH of 4.6-8.0

Glomerular filtration rate (GFR)

Rate of filtrate formed each minute ~ 125 mL/min

Does not contain any large molecules, amount is related to perfusion rate (higher=higher)

Autoregulatory mechanisms

Geared at maintaining a constant flow of blood to the kidneys; response to blood pressure

Juxtaglomerular complex

Monitors NaCl concentrations; determines how much renin should be released (meaning renin comes from here)

Renin

Regulates BP using angiotensin II (when renin releases, it stimulates angiotensin I, which is then stimulated into angiotensin II)

Ultimately plays a role in aldosterone release

Tubular components

Site of selective reabsorption and/or secretion of substances

Aldosterone

Promotes water reabsorption and excretion of K+

Antrial Natriuretic Peptide (ANP)

Inhibits Na reabsorption, renin, ADH, and aldosterone release

Regulation of pH

Kidneys control reabsorption of bicarbonate and elimination of hydrogen with the goal of maintaining pH

what should our pH be?

7.35-7.45

Uric acid

Product of purine metabolism, excess levels in blood can cause gout, and in can cause stones in urine

Urea elimination

End product of protein metabolism, regulated by kidneys

Normal BUN levels

8-20 mg/dl

Inverse relationship with GFR (decreased GFR = increased BUN)

RAAS

Renin-Angiotensin-Aldosterone system that is stimulated by low renal perfusion

Normal levels of hemoglobin

men 14-18 g/dl; Women 12-16 g/dl

Normal levels of hemocrit

Men 45-52%; women 37-47% (approx 3x of hemoglobin)

Vitamin D

Promotes reabsorption of Ca in bones

Normal creatinine levels

0.6-1.2 mg/dL

Normal GFR levels

>125

Lower tract obstruction

Below ureterovesical junction; bilateral; urine can’t leave body

Upper tract obstruction

above ureterovesical junction; unilateral

Hydronephrosis

urine filled dilation of renal pelvis and calices from back pressure

Nephrolithiasis

renal calculi(stones), most common cause of upper urinary tract obstruction

Urolithasis

Urinary calculi

What dietary factor contributes to renal stone formation?

increased calcium intake

Most common renal stone

Calcium stones

Struvite stones

Magnesium ammonium phosphate stones; presence of bacteria that posses the protein “urease”

Uric acid stones

Associated with increased uric acid levels from purine (gout)

Cystine stones

rare; genetic defect

Renal colic

stretching of ureter, acute, and can be painful

non colicky renal pain

from kidney itself

UTI - etiologic factors

E. coli causes 80% of these cases, can be via urosepsis

E. coli adheres to epithelial cells

Most common cause for UTI

incorrect wiping or incorrect cleaning of foley catheter (in hospitalizations)

Cystitis

Lower UTI; involves bladder and is more common in women; main manifestations involves the presence of WBCs in urine

Pyelonephritis

Upper UTI; involves kidneys, tubules, interstitium, and renal pelvis; systemic involvements (chills, fever, headache, or general malaise)

more common in children

most common symptom of UTI for elderly people

confusion

Acute Nephritic syndrome

Infection with group A beta-hemolytic, or certain viruses (measles, mumps, or chicken pox)

can also be known as poststreptococcal glomerulonephritis

Manifestations of acute nephritic syndrome

cola-colored urine, hypertension, edema

Rapidly progressive glomerulonephritis

Severe glomerular injury that does not have a specific cause

Nephrotic syndrome

Group of clinical manifestations, related to osmosis and protein loss (due to increase in glomerular capillary basement membrane permeability)

Manifestations of nephrotic syndrome

Massive proteinuria, hypoalbuminemia (protein loss, generalized edema

Renal tubule acidosis

Defect in the ability to reabsorb HCO3 and/or excrete H+, results from acidosis

Wilm’s tumor

Typically a solitary mass that may occur in one or both kidneys, associated with congenital anomalies

Renal cancer

Renal cell carcinoma is the most common cause, associated with heavy smoking, obesity, and exposure to toxins

Acute renal failure (AKF) or Acute renal injury (AKI)

Fast, but potentially reversible

Three types of AKI or AKF

Prerenal: decreased blood flow to kidneys

Intrarenal: damage to kidney itself

Postrenal: obstructed blood flow

Common signs of AKI or AKF

decreased GFR

Azotemia _ build up of urea and N

Metabolic acidosis

Electrolyte imbalance

(GAME)

Oliguric or Anuric

A phase of AKI/AKF

Decreased a GFR, fluid retention. azotemia

Diuretic

A phase of AKI/AKF

Output increase but tubule scarring and damage may occur

Prerenal failure

Most common cause of AKI/AKF; caused by hypoperfusion (decrease in blood flow)

General cause for prerenal failure

anything that can decrease renal perfusion

Intrarenal Failure

Derived from prerenal failure, leads to ATN

Acute tubular necrosis

death of cells in tubular sections of nephrons, leads to decreased renal function, build up of cellular debris , and eventual postrenal failure

Ischemia ATN

Lack of renal perfusion, can lead to irreversible damage if GFR isn’t improved

Nephrotoxic ATN

Ingestion of substances that are toxic to the kidney

Postrenal failure

Obstruction of urine outflow

Chronic kidney disease (CKD)

Irreversible destruction of nephrons, leading to deterioration of GFR, tubular reabsorption capacity, and endocrine function

High mortality rate

Causes for CKD

HTN

Diabetes mellitus (#1 cause)

clinical manifestations of CKD

build up of BUN or creatinine

Accumulation of azotemia