Electrolyte disturbances cardiovascular tests
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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

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Electrolyte disturbances Cardiovascular Tests

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Electrolyte disturbancesCardiovascular Tests


Definitions!

  • Protons + are positively charged particles (atomic number is the number of protons) example H+

  • Electrons - are the negatively charged particles that spin

  • Neutronsuncharged 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


ACID/BASE BALANCE AND THE BLOOD

[H+]

[OH -]

Acidic

Alkaline (Basic)

Neutral

pH

7

Venous Blood

Arterial Blood

0

14

Acidosis

Alkalosis

7.4

DEATH

DEATH

Normal7.35-7.45

6.8

8.0


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


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-


Control of Acids

  • 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


Acidosis (392)

  • Principal effect of acidosis is

    depression of the CNS through ↓ in synaptic transmission.

  • Generalized weakness

  • Deranged CNS function is

    the greatest threat

  • Severe acidosis causes

    • Disorientation

    • coma

    • death


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


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.


  • ELECTROLYTES

    • Calcium (428-429)

    • Sodium(430)

    • Potassium(175)

    • Magnesium(148)

    • Phosphorus(170)


    • Uncorrected electrolyte abnormalities may have life-threatening consequences. 

    • Important electrolytes include-

    • calcium (Ca),

    • potassium (K),

    • sodium (Na) and

    • magnesium (Mg)


    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


    Hypercalcemia

    • Causes

    • Hyperparathyroidism

    • Cancer with bone metastasis (in particular prostate and breast)


    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)


    Hypokalemia

    Causes

    Drugs (diuretics, beta agonists)

    Diarrhea (laxative abuse)

    Diabetes (uncontrolled)

    Inadequate intake

    • Defined as:

      • Mild: 3-3.2 mmol/L

      • Moderate: 2.5-2.9 mmol/L

      • Severe: <2.5 mmol/L

    • Symptoms

    • May vary from asymptomatic to fulminant respiratory failure

    • Most commonly manifests as weakness, fatigue

    • EKG – prolonged QT, Torsade de Pointes


    HYPERKALEMIA

    Causes:

    Metabolic acidosis

    Hypoglycemia

    Rhabdomyolysis

    Tumor lysis syndrome

    Drugs

    Renal failure

    • Defined as:

    • Mild: >5.1-6.0 mmol/L

    • Moderate: 6.1-7 mmol/L

    • Severe: >7 mmol/L

    • Symptoms

    • Usually only occur above 7 mmol/L

    • Muscle weakness, cardiac arrhythmias

    • EKG – peaked waves, widening of QRS


    Sodium (Na)

    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

    • Normal range: 136-144 mmol/L

    • Sodium-related disorders

    • Hyponatremia

      • Defined as <136 mmol/L

      • Symptoms

      • Headache, nausea, emesis, lethargy

      • Severe hyponatremia can cause seizures, coma, death


    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


    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


    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)


    Hypermagnesemia

    Causes

    Impaired renal function

    Patient receiving large load of magnesium or magnesium-containing 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


    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


    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


    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


    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)


    Hyperphosphatemia

    • May be due to or associated with:

    • Kidney failure

    • Hypoparathyroidism (underactive parathyroid gland)

    • Diabetic ketoacidosis (when first seen)

    • Phosphate supplementation


    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


    Total Cholesterol


    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.


    Identify metabolic syndrome and treat, if present, after 3 months of TLC.

    Clinical Identification of the Metabolic Syndrome - Any 3 of the Following:


    Treat elevated triglycerides. (207)

    ATP III Classification of Serum Triglycerides (mg/dL)


    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.


    High RiskGroup

    • 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%


    Characterized by five major abnormalities

    1.   Obesity (central body and visceral)

    2.   Hypertension

    3.   Insulin resistance (hyperinsulinemia)

    4.   Glucose intolerance

    5. Dyslipidaemia


    Emerging Risk Factors

    • Lipoprotein (a)

    • C-reactive protein (66)

    • Homocysteine (133)

    • Prothrombotic factors

    • Proinflammatory factors

    • Impaired fasting glucose

    • Subclinical atherosclerosis


    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.


    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.


    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)


    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.


    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


    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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