Electrolyte disturbances Cardiovascular Tests

1. Electrolyte disturbancesCardiovascular Tests

2. 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

3. 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

4. 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

5. 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-

6. 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

8. 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

9. 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

10. 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.

12. ELECTROLYTES • Calcium (428-429) • Sodium(430) • Potassium(175) • Magnesium(148) • Phosphorus(170)

13. Uncorrected electrolyte abnormalities may have life-threatening consequences.  • Important electrolytes include- • calcium (Ca), • potassium (K), • sodium (Na) and • magnesium (Mg)

14. 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

15. Hypercalcemia • Causes • Hyperparathyroidism • Cancer with bone metastasis (in particular prostate and breast)

16. 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)

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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)

23. 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

24. 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

25. 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

26. 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

27. 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)

28. Hyperphosphatemia • May be due to or associated with: • Kidney failure • Hypoparathyroidism (underactive parathyroid gland) • Diabetic ketoacidosis (when first seen) • Phosphate supplementation

29. Cardiovascular Tests

30. 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

31. Total Cholesterol

32. 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.

33. Identify metabolic syndrome and treat, if present, after 3 months of TLC. Clinical Identification of the Metabolic Syndrome - Any 3 of the Following:

34. Treat elevated triglycerides. (207) ATP III Classification of Serum Triglycerides (mg/dL)

35. 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.

36. 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%

37. Characterized by five major abnormalities 1.   Obesity (central body and visceral) 2.   Hypertension 3.   Insulin resistance (hyperinsulinemia) 4.   Glucose intolerance 5. Dyslipidaemia

38. Emerging Risk Factors • Lipoprotein (a) • C-reactive protein (66) • Homocysteine (133) • Prothrombotic factors • Proinflammatory factors • Impaired fasting glucose • Subclinical atherosclerosis

39. OTHER PREDICTORS CHD risk factors

40. 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.

41. 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.

42. 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)

43. 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.

44. 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

45. 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)