Transcript Electrolyte disturbances Cardiovascular Tests

Electrolyte disturbances
Cardiovascular Tests
Definitions!
Protons + are positively charged particles
(atomic number is the number of protons) example
H+
Electrons - are the negatively charged
particles that spin
Neutrons uncharged particles that spin
and are made up of quarks
“A neutron walked into a bar and asked how
much for a drink.
The bartender replied,
"for you, no charge."
-Jaime - Internet Chemistry Jokes
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ACID/BASE BALANCE AND THE BLOOD
[H+]
[OH -]
Acidic
Alkaline (Basic)
Neutral
pH
0
Venous Blood
Arterial Blood
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Acidosis
6.8
7
7.4
Normal7.35-7.45
Alkalosis
8.0
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Small changes in pH can produce major
disturbances
Most enzymes function only with narrow
pH ranges
Acid-base balance can also affect
electrolytes (Na+, K+, Cl-)
Can also affect hormones
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The body produces more acids than
bases
Acids take in with foods
Acids produced by metabolism of lipids and proteins
Cellular metabolism produces CO2.
CO2 + H20 ↔ H2CO3 ↔ H+ + HCO3-
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Control of Acids
1.
Buffer systems
Take up H+ or release H+ as conditions
change
Buffer pairs – weak acid and a base
Exchange a strong acid or base for a weak
one
Results in a much smaller pH change
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Acidosis (392)
Principal effect of acidosis is
depression of the CNS through ↓ in
transmission.
Generalized weakness
Deranged CNS function is
the greatest threat
Severe acidosis causes
synaptic
Disorientation
coma
death
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Alkalosis
 Alkalosis causes over excitability of the central and
peripheral nervous systems.
 Numbness
 Lightheadedness
 It can cause :
Nervousness
muscle spasms or tetany
Convulsions
Loss of consciousness
Death
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Anion Gap
The difference between [Na+] and the sum of [HC03-] and
[Cl-].
[Na+] – ([HC03-] + [Cl-]) =
140 - (24 + 105) = 11
Normal = 12 + 2
Clinicians use the anion gap to identify the cause of
metabolic acidosis.
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ELECTROLYTES
Calcium (428-429)
Sodium(430)
Potassium(175)
Magnesium(148)
Phosphorus(170)
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Uncorrected electrolyte abnormalities may have lifethreatening consequences.
Important electrolytes includecalcium (Ca),
potassium (K),
sodium (Na) and
magnesium (Mg)
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CALCIUM
Hypocalcemia
Symptoms
Tetany, seizures
Circumoral numbness
Paresthesias
Carpopedal spasm
Latent tetany may result in Trousseau and Chvostek
signs
Electrocardiogram (EKG) – prolonged QT, Torsades de
Pointes
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Hypercalcemia
Causes
Hyperparathyroidism
Cancer with bone metastasis (in particular prostate and
breast)
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Potassium (K)
Cellular distribution affected by insulin and beta-
adrenergic receptors, renal excretion
3 mechanisms control potassium
Intake
Distribution between intracellular and extracellular fluid
Renal excretion
Rapid changes have life-threatening consequences
May affect serum pH (inverse relationship)
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Hypokalemia
Causes
Defined as:
Drugs (diuretics, beta
Mild: 3-3.2 mmol/L
agonists)
Diarrhea (laxative abuse)
Moderate: 2.5-2.9 mmol/L
Diabetes (uncontrolled)
Severe: <2.5 mmol/L
Inadequate intake
Symptoms
May vary from asymptomatic to fulminant respiratory
failure
Most commonly manifests as weakness, fatigue
EKG – prolonged QT, Torsade de Pointes
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HYPERKALEMIA
Causes:
Defined as:
Metabolic acidosis
Mild: >5.1-6.0 mmol/L
Hypoglycemia
Rhabdomyolysis
Moderate: 6.1-7 mmol/L
Tumor lysis syndrome
Severe: >7 mmol/L
Drugs
Symptoms
Renal failure
Usually only occur above 7 mmol/L
Muscle weakness, cardiac arrhythmias
EKG – peaked waves, widening of QRS
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Sodium (Na)
Normal range: 136-144 mmol/L
Sodium-related disorders
Hyponatremia
Causes:
thiazide diuretics, osmotic
diuresis, adrenal insufficiency,
ketonuria
syndrome of inappropriate
antidiuretic hormone (SIADH),
hypothyroidism, HIV, certain
forms of cancer
psychogenic polydipsia, multiple
tap water enemas, congestive
heart failure
Defined as <136 mmol/L
Symptoms
Headache, nausea, emesis, lethargy
Severe hyponatremia can cause seizures, coma, death
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Hypernatremia
Defined as serum sodium >144 mmol/L
Symptoms:
Mimics symptoms of hyponatremia
Causes
Insensible losses (e.g., fever)
Diabetes insipidus (central, nephrogenic)
Cushing disease
Hyperaldosteronism
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Magnesium (Mg)
Physiologically – magnesium aids in cellular transport of
Ca, Na, K
Balance maintained by kidneys
Normal range in serum: 1.6-2.6 mg/dL
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Hypomagnesemia




Causes
Gastrointestinal losses – diarrhea, small
bowel surgery, malabsorption, pancreatitis
Renal losses – diuretics, nephrotoxic
drugs, tubular necrosis
Uncontrolled diabetes mellitus
Is a common disorder
Symptoms
Neurologic manifestations similar to hypocalcemia
Tetany, muscle weakness, Chvostek and Trousseau
signs
 EKG – widening QRS or QT and peaked T waves,
premature ventricular contractions (PVCs)
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Hypermagnesemia
Causes
Impaired renal function
Patient receiving large load of
magnesium or magnesiumcontaining drugs
Parenteral magnesium therapy
for preeclampsia
Elderly patients with gastrointestinal
disease on cathartics
Defined as serum Mg >2.6 mg/dL
Symptoms
Usually mild elevation and therefore no symptoms
Symptoms when Mg ≥4 mg/dL
4-6 mg/dL: nausea, lethargy, flushing
6-10 mg/dL: somnolence, hypocalcemia, hypotension, bradycardia
>10 mg/dL: respiratory paralysis, complete heart block, cardiac
arrest
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Phosphorus
Phosphates are vital for energy production, muscle and nerve function, and
bone growth
An important role as a buffer, helping to maintain the body’s acid-base
balance
70% to 80% as calcium phosphate – bones/teeth
10% in muscle
1% in nerve
Beans, peas and nuts, cereals, dairy products, eggs, beef, chicken, and
fish contain significant amounts of phosphorus
Intestinal absorption and renal excretion maintains blood levels
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Phosphorus
Phosphorus testing often is performed as a follow-up to
an abnormal calcium level and/or related symptoms, such
as fatigue, muscle weakness, cramping, or bone problems
To ensure patient is not excreting or retaining excessive
amounts in the presence of kidney disorder, kidney stones,
or uncontrolled diabetes
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Phosphorus
Also known as P, PO4, Phosphate
When to get tested?
As a follow-up to:
 an abnormal calcium level
 kidney disorder
uncontrolled diabetes, and
On calcium or phosphate supplements
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Hypophosphatemia
Dietary deficiencies in phosphorus are rare but may be seen with alcoholism
and malnutrition
May be associated with:
Hypercalcemia, especially due to hyperparathyroidism
Overuse of diuretics
Severe burns
Diabetic ketoacidosis (after treatment)
Hypothyroidism
Hypokalemia
Chronic antacid use
Rickets and osteomalacia (due to Vitamin D deficiencies)
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Hyperphosphatemia
May be due to or associated with:
Kidney failure
Hypoparathyroidism (underactive parathyroid gland)
Diabetic ketoacidosis (when first seen)
Phosphate supplementation
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Cardiovascular Tests
STEP 1: Determine lipoprotein levels - obtain complete
lipoprotein profile after 9- to 12-hour fast
(78)
ATP III Classification of LDL, Total, and HDL Cholesterol (mg/dL)
•LDL Cholesterol - Primary Target of Therapy
<100
100-129
130-159
160-189
190
Optimal
Near Optimal/Above
Optimal
Borderline High
High
Very high
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Total Cholesterol
<200
•
200-239
240
HDL Cholesterol
<40
60
Desirable
Borderline High
High
Low
High
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Determine presence of major risk factors
Major Risk Factors (Exclusive of LDL Cholesterol)
That Modify LDL Goals
Cigarette smoking
Hypertension (BP 140/90 mmHg or on antihypertensive
medication)
Low HDL cholesterol (<40 mg/dl)*
Family history of premature CHD (CHD in male first degree
relative <55 years; CHD in female first degree relative <65 years)
Age (men 45 years; women 55 years)
* HDL cholesterol 60 mg/dL counts as a "negative" risk factor;
its presence removes one risk factor from the total count.
Note: in ATP III, diabetes is regarded as a CHD risk equivalent.
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Identify metabolic syndrome and treat, if present, after 3
months of TLC.
Clinical Identification of the Metabolic Syndrome - Any 3 of the Following:
Risk Factor
Defining Level
Abdominal obesity*
Men
Women
Waist circumference**
>102 cm (>40 in)
>88 cm (>35 in)
Triglycerides
HDL cholesterol
Men
Women
150 mg/dL
<40 mg/dl
<50 mg/dl
blood pressure
130/ 85 mmHg
Fasting glucose
110 mg/dL
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Treat elevated triglycerides. (207)
ATP III Classification of Serum Triglycerides (mg/dL)
< 150
150-199
200-499
500
Normal
Borderline high
High
Very high
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Coronary Risk Screen
CHOLESTEROL: is normally synthesized by the liver and is important as a
constituent of cell membranes and a precursor to steroid hormones. Its level in the
bloodstream can influence the pathogenesis of certain conditions, such as the
development of atherosclerotic plaque and coronary artery disease
TRIGLYCERIDES: Triglycerides are esters of glycerol and fatty acids. Since they
and cholesterol travel in the blood stream together, they should be assessed
together.
HDL: A complex of lipids and proteins in approximately equal amounts that
functions as a transporter of cholesterol in the blood. High levels are associated
with a decreased risk of atherosclerosis and coronary heart disease.
LDL: A complex of lipids and proteins, with greater amounts of lipid than protein,
which transports cholesterol in the blood.
CHOL/HDL RATIO: A ratio of lipids for determining possible cardiac risk factors.
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High Risk Group

1.
2.
3.
4.
5.
Have either CAD or any one of five CAD "risk
equivalents":
Diabetes mellitus
Peripheral vascular disease
Carotid artery disease
Abdominal aortic aneurysm
A calculated 10-year risk for a coronary event that
exceeds 20%
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Characterized by five major
abnormalities
1.
2.
3.
4.
5.
Obesity (central body and visceral)
Hypertension
Insulin resistance (hyperinsulinemia)
Glucose intolerance
Dyslipidaemia
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Emerging Risk Factors
Lipoprotein (a)
C-reactive protein (66)
Homocysteine (133)
Prothrombotic factors
Proinflammatory factors
Impaired fasting glucose
Subclinical atherosclerosis
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OTHER PREDICTORS
CHD risk factors
TESTS FOR
ACUTE HEART ATTACKS
(MYOCARDIAL INFARCTION)
CK-II MB (CREATININE KINASE) (88)
TROPONINS(209)
Creatine Kinase (CK)(87)
CK is an enzyme found in the heart and muscles. Increased CK-
MB is seen with heart muscle damage.
Increased CK-MM is noted with skeletal muscle injury. Strenuous
exercise, weight lifting, surgical procedures, high doses of aspirin
and other medications can elevate CK.
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Troponin T (cTNT)
Troponin T is a protein found in the blood and is related to
contraction of the heart muscle.
Troponin T is valuable for detecting heart muscle damage and
risk.
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Ultra Sensitive C-reactive Protein (US-CRP)(66)
Goal values:
Less than 1.0 mg/L = Low Risk for CVD
1.0-2.9 mg/L = Average Risk for CVD
Greater than 3.0 mg/L High Risk for CVD
(levels above these ranges indicate increased risk for
heart and blood vessel disease)
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B-Type Natriuretic Peptide (BNP) blood test
BNP is a substance secreted from the ventricles or
lower chambers of the heart in response to changes in
pressure that occur when heart failure develops and
worsens.
Increases when heart failure symptoms worsen, and
decreases when the heart failure condition is stable.
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B-Type Natriuretic Peptide (BNP) blood test
BNP levels below 100 pg/mL indicate no heart failure
BNP levels of 100-300 suggest heart failure is present
BNP levels above 300 pg/mL indicate mild heart failure
BNP levels above 600 pg/mL indicate moderate heart failure.
BNP levels above 900 pg/mL indicate severe heart failure.
BNP accurately detected heart failure 83% of the time and reduced
clinical indecision from 43% to 11%.
-January 2008 issue of the Journal of the American College of
Cardiology
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Homocysteine (Hcy) (133)
An amino acid. High levels are related to early development of heart and blood
vessel disease
Goal value: less than 10 umol/L
High levels of homocysteine are related to the early development of heart and blood
vessel disease. In fact, it is considered an independent risk factor for heart disease.
High homocysteine is associated with low levels of vitamin B6, B12 and folate and
renal disease.
For the most accurate results, wait at least two months after a heart attack,
surgery, infection, injury or pregnancy to check this blood level.
Evaluation of hyperlipidemia (431)
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