1. PreWork This powerpoint will only be helpful if you run it as a slide show.

2. PreWork Objectives Understand the respiratory and metabolic mechanism for eliminating acid Know the normals for Arterial Blood Gasses and Venous Electrolytes Explain ADH and Aldosterone effects on sodium and water. Explain the effects of sodium and free water on volume and serum sodium Explain hormonal regulation of Ca++ and P04

3. Problem: Metabolism Produces Acid H 2 SO 4 H 3 PO 4 HCl etc.

4. Getting Rid of Acid Bicarbonate Reabsorption by the Kidneys (Metabolic) Carbonic Anhydrase H 2 CO 3 Urine Blood HCO 3 - H+H+H+H+

5. The Lungs Eliminate CO2 (Respiratory) Getting Rid of Acid H 2 CO 3 HCO 3 - H+H+H+H+ H 2 O + CO 2 + Acidic Carbonic Acid

6. The Lungs Eliminate CO 2 (Respiratory) Getting Rid of Acid H 2 CO 3 HCO 3 - H+H+H+H+ H 2 O + CO 2 + AcidpH Carbonic Acid Alveoli

7. Normals Arterial Blood pH:7.35-7.45 pCO 2 :40 PO 2 :100 HCO 3 25

8. Normals Venous Lytes Sodium: 140 Potassium: 4.5 Chloride 100 Total CO 2 26

9. Total CO 2 pCO 2 =40mm Hg u 40mm Hg EQUALS u 1.2 mEq / L dissolved CO 2 u + 25 mEq /L of HCO 3 u =26 mEq / L = Total CO 2 Dissolved in Water ….. Click Here to Play That Again if you didn’t get it

10. Sodium and Water Prework

11. Volume and Tonicity

12. Salt rules volume Intracellular Extracellular H20H20 H20H20 Serum Sodium 140 mEq/L (Unchanged) Serum Sodium 140 mEq/L This represents normal sodium and volume. Extracellular space is the vascular plus tissue Note that intracelluar space is 2/3 of total body water Salt Rules Volume

13. Free Water Rules Serum Sodium Intracellular Extracellular Serum Sodium 125 mEq/L (hyponatremia) Serum Sodium 140 mEq/L This represents normal sodium and volume. Extracellular space is the vascular plus tissue Note that intracelluar space is 2/3 of total body water H20H20 H20H20 No Clinically Significant Volume Change (Water Spreads Out) H20H20 H20H20

14. The Challenge Figure out how the Renin- Angiotensin-Aldosterone system and how ADH relate to the above examples of sodium and water. What turns them on and what turns them off.

15. Calcium And Phosphate Prework Prework questions on Calcium and Phosphate will be easy. Exam questions will be slightly less easy.

16. Calcium

17. Normal value:  Total: 8.5–10.5 mg/dL (2.1–2.7 mmol/L)  Ionized (free): 4.6–5.2 mg/dL (1.15–1.38 mmol/L) Function  Bone and teeth  Neuromuscular activity (SA node, AV node)  Endocrine/exocrine function  Platelet function  Muscle cell contraction

18. Calcium Regulation PTH   serum calcium Vitamin D   serum calcium Calcitonin   serum calcium Calcium homeostasis figure (next slide)

19. http://www.biol.andrews.edu/fb/spring/Chap.45-%20Endocrinology/4510.jpg

20. Corrected Calcium Only ionized (unbound) calcium is active Calcium must be corrected when there is a low albumin (a larger percent is ionized) For each 1mg/dl change in albumin from normal, 0.8mg/dl change in Ca 2+ [(4 – alb) x 0.8] + serum Ca 2+ Ex. Alb 2.3 Ca 2+ 7.6  Corrected calcium =  [(4-2.3) x 0.8] + 7.6 = 8.96 mg/dL

21. Hypocalcemia Serum Ca 2+ < 8.5 mg/dL Pathophysiology  Hypoparathyroidism  Vitamin D deficiency  Hypomagnesemia  Hyperphosphatemia, 2 o hypoparathyroidism  Medications/chelating agents Bisphosphonates, loop diuretics, calcitonin, phenytoin

22. Hypocalcemia Clinical Presentation  Acute Fatigue, irritability, confusion, seizures Muscle cramps, spasms, tetany  Chronic Prolonged QT interval Brittle nails, hair loss

23. Hypocalcemia Treatment Always correct calcium for albumin!! Depends on acuity and severity Check a magnesium level (find out why for the exam! ) Calcium supplementation  IV  PO

24. IV Calcium Acute symptomatic patients Calcium chloride  1 gm IV (27% elemental)  Very irritating to veins Calcium gluconate  2-3 gm IV (9% elemental)   availability in liver disease

25. PO Calcium Chronic asymptomatic patients Corrected symptomatic patients 1-3 g/day of elemental calcium ± vitamin D Take with meals, in divided doses for best absorption

26. PO Calcium Calcium Salt Elemental Calcium Carbonate (Tums ®, OsCal ®, VIACTIV ® ) 40% Acetate (PhosLo ® ) used as a phosphate binder 25% Citrate (Citracal ® ) Important: Use when patient has little stomach acid (PPI) 21%

27. Hypocalcemia Monitoring Albumin, magnesium levels Symptomatic patient  Serum and ionized calcium levels every 4-6 hrs after IV calcium  Serum calcium every 24-48 hrs during oral therapy, then 1-2 times weekly

28. Hypercalcemia Serum Ca 2+ > 10.5 mg/dL Pathophysiology  Primary hyperparathyroidism**  Malignancy**  Other High bone turnover, sarcoidosis Medications (thiazides, lithium, vitamin D)

29. Hypercalcemia Clinical Presentation  Depends on degree and onset  GI – N/V, anorexia, constipation  CV – short QT, prolonged PR & QRS  Neuro – fatigue, weakness, confusion  Renal – polyuria, nocturia, nephrolithiasis

31. Hypercalcemia Treatment DrugDoseOnset 0.9% NS (plus furosemide below) * First line therapy 200-300 cc/hr24-48 hrs Furosemide40-80 mg IV q 1-4 hrsUpon diuresis Calcitonin4 units/kg SC or IM q 12 hrs1-2 hrs BisphosphonatesPamidronate 30-90 mg IV over 2-24 hrs 1-2 days Prednisone40-60 mg/day1-2 weeks

32. Hypercalcemia Treatment Other treatment options  Gallium nitrate, mithramycin Monitoring  Albumin  ECG  Serum Ca 2+ q 6-12 hrs if symptomatic  Serum Ca 2+ daily if mild-moderate

33. Summary of Calcium Calcium regulation  PTH, Vitamin D, calcitonin  Corrected calcium Oral calcium products Treatment of hypercalcemia

34. Phosphorus

35. Normal value 2.7-4.5 mg/dL Function  Phospholipid membrane  Supports bone and teeth  Metabolism of nutrients  Source of ATP (energy, kinda critical)

36. Phosphorus Source  Meats, dairy, eggs Regulation  Kidney

37. Hypophosphatemia Mild to Moderate 1-2 mg/dL Severe < 1 mg/dL Pathophysiology  Decreased intake/absorption Vitamin D deficiency, phosphate binders  Increased excretion Diuretics, hyperparathyroidism  Intracellular shift Parenteral nutrition, insulin

38. Hypophosphatemia Clinical Presentation  Neuro – irritability, weakness, seizures  Muscular – myalgia  Hematologic – hemolysis  Pulmonary – respiratory distress  Other – osteomalacia, arrhythmias

39. Hypophosphatemia Tx Mild – moderate  PO 50-60 mmol/day divided in 3-4 doses o Neutra-Phos 1-2 packets QID mixed in 2.5 oz water or juice o K-Phos Neutral 1-2 tabs QID with water NOTE: Dose in mmol NOT mEq

40. Hypophosphatemia Tx Mild – moderate  IV 0.08-0.15 mmol/kg IV Repeat until serum phosphorus > 2 mg/dL

41. Hypophosphatemia Tx Severe  IV 0.25-0.5 mmol/kg IV Repeat until serum phosphorus > 2 mg/dL

42. Phosphorus Replacement ProductPhos ContentNa ContentK Content K-Phos Neutral* 250mg8 mmol13 mEq1.1 mEq Fleet Phospho-soda* Typically used as laxative 20 mmol24 mEq0 Sodium Phosphate3 mmol/mL4 mEq/mL0 K-Phos Original Dissolving Tablets 3.603.7mEq Neutra-Phos* 250mgRecently discontinued Doesn’t matter! Neutra-Phos K* 250mgRecently discontinued Doesn’t matter! *Oral agents

43. Hypophosphatemia Monitoring  IV therapy Serum phosphorus every 6 hrs  PO therapy Serum phosphorus daily  Renal function, BP (IV)  Adverse events – diarrhea (PO), soft tissue calcification, hypocalcemia, hypotension (IV)

44. Hyperphosphatemia Serum phos > 4.5 mg/dL Pathophysiology  Decreased urinary excretion Renal failure, hypoparathyroidism  Increased intake Parenteral nutrition, phosphate enemas  Extracellular shift Acidosis

45. Hyperphosphatemia Clinical Presentation  N/V, muscle pain/weakness, hyperreflexia, tetany  Soft Tissue calcification Due to calcium-phosphate product Goal is less than 55.

46. Hyperphosphatemia Tx Restrict dairy products Phosphate binders  Aluminum and magnesium-based antacids No longer first line, avoid in renal failure  Calcium (Drug of first choice unless Calcium is high)  Sevelamer Binding resin Usually given with meals

47. Hyperphosphatemia Monitoring  Serum calcium level  Serum phosphorus level daily  Renal function

48. Summary of Phosphorus IV vs. PO replacement  Give IV phosphorus when severe hypophosphatemia Medications affecting serum levels  Phosphate-binders, calcium, diuretics, insulin, vitamin D