blood gases, electrolytes, osmolality, hormones

Henderson Hasslebach

equation measures blood pH from bicarc:carbonic acid ratio

dec

inc/dec SHBG inc free testosterone

inc

inc/dec SHBG dec free testosterone

inc, dec, dec

pCO2, pH, pO2 when blood gas testing is prolonged or not on ice (glycolysis not inhibited)

dec, inc, inc

pCO2, pH, pO2 when blood gas testing exposed to air (bubbles, tube uncapped)

FP depression

colligative property used to measure osmolality

SLUMPED

conditions cause increased osmolal gap (>15)

Na, glucose, BUN

particles included in calculation of osmolality

ADH, thirst, ICF

ways to restore ECF osmolality (inc bp) with low H2O/bp

albumin

protein that makes up majority of anion gap

dec (inc)

inc/dec unmeasured cations (inc/dec measured) with increased anion gap

inc (dec)

inc/dec unmeasured anions (inc/dec measured) with increased anion gap

inc

anion gap inc/dec with SLUMPED

dec

anion gap inc/dec with

-nephrotic syndrome (low albumin)

-liver disease (low albumin)

-hypercalcemia

-Li therapy

dec (inc)

inc/dec unmeasured anions (inc/dec measured) with decreased anion gap

inc (dec)

inc/dec unmeasured cations (inc/dec measured) with decreased anion gap

Na, K

cations measured in anion gap eq

Cl, HCO3

anions measured in antion gap eq

dec

CO2 is inc/dec in

-metabolic acidosis

-diabeteic ketoacidosis

-salicylate pois

inc

CO2 is inc/dec in

-metabolic alkalosis

-emphysema

-severe emesis

blood

buffer system that HCO3 is part of

Ca

regulates

-skeletal, smooth, cardiac musc contraction

-nerve impulse transmission

-enzyme activity

-coag

regulated by

-PTH

-vitD

-calcitonin

acid

acid/basic environment leads to more free Ca (less bound)

basic

acid/basic environment leads to less free Ca (more bound)

inc

Ca is inc/dec with

-primary hyperparathyroidism

-bone malignancy

-renal failure

dec

Ca is inc/dec with

-hypoparathyroidism

-dec albumin

-chronic renal failure

-Mg deficiency

-vitD deficiency

dec

hypocalcemia occurs with inc/dec albumin

phosphate

-important for carb metab

regulated by

-PTH

-vitD

-FGF23

inc

phosphate is inc/dec with

-hypoparathyroidism

-neoplastic diseases

-renal failure

-intense exercise

-lymphoblastic leukemia

dec

phosphate is inc/dec wtih

-diabetic ketoacidosis

-hyperparathyroidism

-asthma

-alcoholism

-malabsorption

parathyroid (PTH)

regulates Ca and phosphate levels with kidneys, bones, and intestines

FGF23

-hormone from kidneys

-inhibits phosphate excretion, Ca absorption, and 1a hydroxylase activation by kidneys

-released with high Ca and low phosphate

inc, dec, inc, dec

serum Ca, phosphate and urine Ca, phosphate with primary hyperparathyroidism

dec, inc, inc, dec

serum Ca, phosphate and urine Ca, phosphate with secondary hyperparathyroidism

all inc

serum Ca, phosphate and urine Ca, phosphate with tertiary hyperparathyroidism

dec, inc, inc, dec

serum Ca, phosphate and urine Ca, phosphate with hypoparathyroidism (autoimmune, inborn error, accidental removal)

EDTA, citrate, oxalate

tube additives that should not be used to collect sample for Mg masurement

-chelate Mg and Ca

magnesium (Mg)

-regulated by kidneys

-inc reabs with inc PTH

inc

Mg inc/dec with

-renal failure

-antacid overuse

dec

Mg inc/dec with

-hyperparathyroidism (high Ca)

-GI disorders

-DM

-alcoholism with dietary insuff

chlorine (Cl)

maintains

-blood osmolality

-blood vol

-electrical neutrality

chloride shift

term describes Cl into cell with HCO3 into plasma

pilocarpine iontophoretic (>60)

CF sweat test

inc

inc/dec chlorine with

-prolonged diarrhea

-renal tubular disease

-dehydration

-excess loss of HCO3

dec

inc/dec chlorine with

-excess vomiting

-diuretic overuse

-burns

-low aldosterone

potassium (K)

-intracellular cation

-cardiac and skeletal muscle contraction

-imbalances cause arrythmias

-released during PLT clotting

-released with hemolysis

plasma

serum/plasma has lower K during clotting

inc

potassium is inc/dec in

-renal failure

-low aldosterone (Addisons)

-metabolic acidosis

-hemolysis

-leukemia/chemo

dec

potassium is inc/dec in

-high aldosterone (Conns, Cushings)

-diuretic/laxative overuse

-excess insulin

-diarrhea/vom

kidneys

where renin is secreted

low

high/low bp signals to kidneys to secrete renin

vasoconstriction, aldosterone

RAAS action to inc bp

retention

aldosterone promotes retention/secretion of Na and H2O by kidneys

secretion

aldosterone promotes retention/secretion of K and H by kidneys

inc

inc/dec aldosterone with

-primary: Conn’s, adrenal adenoma/disease

-secondary: renin-angiotensin disorder, renin-secreting tumor

dec

inc/dec aldosterone with

-Addison’s disease

-adrenal atrophy

-21 a hydroxylase CAH

HVA, VMA, metanephrine

catecholamine metabolism end products

MAO, COMT

enzymes in catecholamine metabolism

dopamine, norepinephrine, epinephrine

catecholamines

dopamine

HVA precursor catecholamine

norepinephrine (normeta)

VMA precursor catecholamine

epinephrine

metanephrine precursor catecholamine

cortisol

-adrenal gland hormone

-stim by CRH and ACTH

-dec immune system, inc glucose, protein, lipolysis metabolism

Addison’s disease

-adrenal hypofunction due to glucocorticoid use, autoimmunity (atrophy), TB

-test: ACTH stim → no response

Cushing’s syndrome

-adrenal hyperfunction due to exogenous cortisol admin, adrenal malignancy, ACTH secreting tumor

-test: high dose dexameth → no response

Cushing’s disease

-adrenal hyperfunction due to ACTH hypersecretion (pituitary or hypo)

-test: high dose dexameth → suppressed

Conn’s

-adrenal hyperfunction due to adrenal adenoma in zona glomerulosa cells

-screen: aldosterone:renin ratio → high

K

Na/K is elevated in Addison’s disease

syndrome

Cushing’s disease/syndrome is a result of a problem at the adrenal glands

disease

Cushing’s disease/syndrome is a result of a pituitary tumor

inc

aldosterone is inc/dec in Conn’s

21

CAH hydroxylase enzyme that results in inc testosterone, low aldosterone (low bp)

17

CAH hydroxylase enzyme that results in dec testosterone, inc aldosterone (high bp)

11

CAH hydroxylase enzyme that results in inc testosterone, inc bp (not aldosterone → 11 deoxycortisol)

AFP

elevated in neural tube defect

AFP

elevated in trisomy 13 (Patau’s)

uE3, hCG

decreased in trisomy 18 (Edward’s)

dec

uE3 and hCG are inc/dec in trisomy 18 (Edward’s)

AFP, uE3

decreased in trisomy 21 (Down’s) and Turner’s

hCG, inhibin A

elevated in trisomy 21 (Down’s) and Turner’s

inc

hCG and inhibin A are inc/dec in trisomy 21 (Down’s) and Turner’s

dec

AFP and uE3 are inc/dec in trisomy 21 (Down’s) and Turner’s

dec/n, dec

FSH/LH, testosterone with pre-testicular infertility (hypo/pit lesions)

inc, dec

FSH/LH, testosterone with testicular infertility (congenital - Kleinfelter’s xxy, acquired - chemo, tumor)

n

FSH/LH, testosterone with mechanical infertility

dec, inc

FSH/LH, estradiol with hypo/pituitary issues due to tumors, stress, illness, drugs, prolactinoma

inc, dec

FSH/LH, estradiol with ovarian issue (tumor, infection, PCOS, Turner’s)

n

FSH/LH, estradiol with uterine/fallopian issue (tumors, endometrial damage, infection)

hypo

GHRH is released from hypo/pit

pit

GH is released from hypo/pit

liver (IGF-1)

GH target

glucose suppression

-acromegaly/gigantism test

-will not change GH

dec

glucose administration suppression should inc/dec GH if normal, but does not change if adenoma

hypo

CRH released from hypo/pit

pit

ACTH released from hypo/pit

adrenal glands (cortisol)

ACTH target

high dose dexamethasone suppression (HDDS)

test for Cushing’s syndrome/disease → change in ACTH?

disease

HDDS test dec cortisol in Cushing’s syndrome/disease

Arg, L-dopa, insulin (stimulation)

test for dwarfism (low GH)

-no change in GH if adenoma (inc if normal or if primary (IGF receptor issue))

ACTH (stimulation)

test to differentiate primary vs secondary/tertiary cortisol deficiency