1 / 60

Moonlight Medicine

Moonlight Medicine. Laboratory Interpretation. Adrian Paul J Rabe, MD, DPCP. Laboratory Interpretation. Supplements the history and physical examination Objective evidence of disease/health. Laboratory Interpretation. Complete blood count Bleeding tests PT/PTT, Bleeding time

ham
Download Presentation

Moonlight Medicine

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Moonlight Medicine Laboratory Interpretation Adrian Paul J Rabe, MD, DPCP

  2. Laboratory Interpretation • Supplements the history and physical examination • Objective evidence of disease/health

  3. Laboratory Interpretation • Complete blood count • Bleeding tests • PT/PTT, Bleeding time • Blood chemistry • Electrolytes (Na, K, Ca, Mg) • BUN and Creatinine • Liver enzymes (AST, ALT) and bilirubins • Urinalysis • Arterial Blood Gas

  4. CBC

  5. Complete Blood count • Hemoglobin and Hematocrit • High hemoglobin: Erythrocytosis • High hematocrit: Dehydration (hemoconcentration) or erythrocytosis • Low hemoglobin/hematocrit: anemia

  6. Complete Blood count • Hemoglobin and Hematocrit • MCV – size of the RBC (“-cytic”) • MCH – amount of hemoglobin in the RBC (“-chromic”) • MCHC – concentration of hemoglobin the RBC • RDW – distribution of cell sizes

  7. Complete Blood count • Hemoglobin and Hematocrit • MicrocyticHypochromic (ITIM) • Iron deficiency anemia or chronic blood loss • Anemia of chronic inflammation • Thalassemia • Myelodysplasia • NormocyticNormochromic • Early stages of microcytic, hypochromic disease • Acute blood loss • Hemolytic Anemia • Megaloblastic • Folate or Vitamin B12 deficiency

  8. Complete Blood count • Hemoglobin and Hematocrit • Transfusion changes • For every unit of packed RBC, increase in 10 g/L • Start of equilibration: 6 hours post transfusion • Full equilibration: 72 hours post transfusion

  9. Complete Blood count • WBC • Neutrophils and stabs • Elevated: Bacterial or early viral Infection, Stress, Inflammation • Low: Neutropenia • Absolute neutrophil count (ANC) = WBC x (Neutrophils in %) x 1000 • Lymphocytes • Elevated: viral/fungal/mycobacterial infection • Low: Lymphopenia • Absolute lymphocyte count (ALC) = same as ANC

  10. Complete Blood count • Platelets • Very evanescent • Low platelets: Consumption, Viral infection • Hard to predict platelet count after transfusion • Adults: never transfuse less than 4 units • Coats the tubing • A Repeat platelet count should be taken immediately up to 2 hours post transfusion

  11. Bleeding Tests

  12. Laboratory Interpretation • PT/PTT • Prothrombin time: Measures the extrinsic pathway (1572 = Factors 1, 10, 5, 7 and 2) • Liver disease: poor production of factor VII • Warfarin • Partial thromboplastin time: Measures the intrinsic pathway • Heparin • APAS • Coagulation factor deficiency (hemophilia) • Both prolonged • DIC • End-stage liver disease • Warfarin

  13. Laboratory Interpretation • Bleeding Time • Does not predict bleeding risk even in surgery • No longer recommended

  14. Blood Chemistry

  15. BUN and Creatinine • BUN – produced by the body and converted through the urea cycle • Increased BUN: Increased production • GI bleed • Creatinine – produced by the muscles, excreted by the kidney with little tubular reabsorption • Increased Creatinine: Increased production or decreased clearance

  16. BUN and Creatinine • BCR = BUN:Creatinine ratio • BUN/Creatinine in mmol x 247 • If > 20 = pre-renal • If 10-15 = intrinsic renal • Replaced by the Fractional excretion of sodium (FENa) • (UNaPCr)/(PNaUCr) • If < 1% = pre-renal • If > 2% = intrinsic renal failure

  17. BUN and Creatinine • Creatinine Clearance = GFR • (140-age) x weight x 88.4 (x 0.85 if female) 72 x Plasma creatinine • Estimates amount of creatinine filtered

  18. Sodium (Na) • Correlated with body water • Sodium is normally present in equimolar amounts • Water diffuses through semipermeable compartments to equilibrate

  19. Sodium (Na) • Total body water • % body water x kg body weight • Males: 60% • Females and Elderly (Age > 60): 50% • Plasma osmolality • 2(Na+K) + BUN + RBS in mmol/L • BUN/2.8 if in mg/dL • RBS/18 if in mg/dL • Normal: 275-290 mmol/L

  20. Sodium (Na) • Total body water • 50 kg male? • 70 kg female? • Plasma osmolality • Na 135, K 3.5, BUN 8, RBS 5 • Na 125, K 4.0, BUN 10, RBS 8

  21. Sodium (Na) • Hyponatremia • Check Plasma osmolality • High osmolality • Hyperglycemia • Mannitol • Normal osmolality • Hyperlipidemia/proteinemia • Bladder irrigation • Low osmolality • Check Urine output

  22. Sodium (Na) • Hyponatremia (Low osmolality) • Maximal urine output • Primary polydipsia (patient drinks a lot, diluting Na) • Pituitary problem/fever • Poor urine output • Check ECF volume

  23. Sodium (Na) • Hyponatremia (Low osmolality, Poor UO) • Increased ECF volume (dilutional) • Heart failure • Liver failure • Kidney failure/nephrotic syndrome • Normal ECF volume • SIADH • Hypothyroidism • Adrenal insufficiency • Decreased ECF volume • Loss of Na (renal, sweat, diuretics)

  24. Sodium (Na) • Hypernatremia • Check ECF volume • High ECF volume • Use of hypertonic solutions • Low ECF volume • Check Urine output

  25. Sodium (Na) • Hypernatremia (Low ECF volume) • Minimal urine output • Free water losses/Dehydration • Good urine output • Check urine osmolality • 24 hour urine TV, Na, K, Crea

  26. Sodium (Na) • Hypernatremia (Low ECF volume, Good UO) • Urine osmolality > 750 • Diuresis • Urine osmolality < 750 • Diabetes insipidus • Central vs Nephrogenic (through response to DDAVP)

  27. Sodium (Na): Correction • Hyponatremia • Increased ECF, no HypoNa symptoms • Used isotonic solutions • Restrict fluid to less than urine output • Loop diuretics • Normal ECF, no HypoNa symptoms • Restrict fluid • Low ECF or with HypoNa symptoms • Correct!

  28. Sodium (Na): Correction • Hyponatremia Correction • No more than 10-12 mmol/day (0.5 mEqs/hour) • Na deficit = TBW x (Desired-Actual Na) • Calculate sodium deficit of 10-12 mmol/day • E.g. Na 100 in a 50 kg female • Desired sodium should be 110-112 • TBW = 50 x 50%= 25 L • Na def = 25 x 12 = 300 mmol in 24h • 0.9% pNSS 1L x 12h

  29. Sodium (Na): Correction • Hypernatremia • Stop ongoing water losses • Should correct dehydration • Oral correction is the safest • No more than 10-12 mmol per day (0.5mmol/hr)

  30. Sodium (Na): Correction • Hypernatremia Correction • Water deficit = TBW x [(Actual-140)/140] • Change in serum Na = (infusate Na – serum Na) (TBW+1) • Amount of infusate = 10 or 12/Change in serum Na • E.g. Na 160 in a 50 kg female • TBW = 50 x 50%= 25 L • Water deficit = 25L x [(160-140)/140] = 3.57 L • Change in serum Na = (77-160)/(25+1) = -3.19 mmol for every liter of 0.45% NaCl • Amount of 0.45% NaCl = 12/3.19 = 3-4 L per day • 0.45 NaCl 1L x 6-8h

  31. Sodium (Na): Correction • 60 kg 23 year-old female with diarrhea and vomiting presents with new-onset seizure • BP 90/60, HR 110, RR 24, Febrile to touch • BUN 12, Crea 127, Na 150, K 3.5 • Creatinine Clearance • Plasma Osmolality • Total Body Water • H20/Na Deficit • Plain LR is available • Change in Na per liter • Order • 57 • 311 • 30 L • 2 L • -0.65mmol/L • 15 L of plain LR • 1L per hour for 4 hours

  32. Sodium (Na): Correction • 50 kg 40 year-old male diabetic with decreased sensorium • BP 140/80, HR 90, RR 28, afebrile • BUN 8, Crea 150, Na 115, K 3.5, Cl 90 • Creatinine Clearance • Plasma Osmolality • Total Body Water • H20/Na Deficit • Daily Na correction • Plain LR is available • 40 • 239 • 30 L • 750 mEqs • 360 mEqs • Plain LR 1L x 115 cc/hr

  33. Potassium (K) • Hypokalemia (<3.5 mmol/L) • 24h urine K and ABG • Urine K > 15 mmol/d • Acidotic = lower GI losses • Alkalotic = vomiting, sweat/renal losses, diuresis • Urine K < 15 mmol/d • Acidotic = DKA, RTA • Alkalotic = vomiting, Bartter’s/Liddle’s, HypoMg

  34. Potassium (K): Correction • Hypokalemia Correction • Concentration • 60 mEqs via central line • 40 mEqs via peripheral line • Rate • ≤ 20 mmol/h unless with paralysis, malignant ventricular arrhythmias • Amount • Every 1mmol/L decrease = 200-400 mmol deficit • pNSS is the ideal medium

  35. Potassium (K): Correction • Hypokalemia Correction • 19 year-old male comes in for progressive lower extremity weakness • K 2.7 • Deficit? • Correction via peripheral line? • 160 to 320 mEqs • pNSS 1L + 40 mEqsKCl x 6 hours, both arms

  36. Potassium (K) • Hyperkalemia (>5.0 mmol/L) • Failure of excretion • Intrinsic Renal problem • Drug-induced (spironolactone, K-sparing diuretics) • Iatrogenic (overcorrection) • Intake of massive amounts

  37. Potassium (K): Correction • Hyperkalemia Correction • Calcium gluconate (10% solution) over 2-3 minutes • NaHCO3 push • Glucose (G-I) solution = 10 u regular insulin + 1 vial D50-50 • Beta-agonists (salbutamol) • Diuretics (Furosemide) • Dialysis

  38. Calcium (Ca) and Albumin • Corrected Calcium • (40-actual albumin) x 0.02 + Actual calcium • Do for both increased and decreased calcium

  39. Calcium (Ca) and Albumin • Hypocalcemia Correction • Chronic • Calcium Carbonate best taken with food (acid soluble) • Calcium citrate can be taken anytime • <600 mg of calcium per dose • Age 19-50: 1000 mg/day • Age 51 and older: 1200 mg/day • Acute, symptomatic • Calcium gluconate 10 mL of a 10% solution diluted in D50-50 or 0.9% saline over 5 minutes • Calcium gluconate drip 10 ampules or 900 mg in 1L of D5 or 0.9% saline over 24 hours

  40. Calcium (Ca) and Albumin • Hypercalcemia Correction • Volume expansion (4-6 L of 0.9% saline in first 24 hours) until normal volume status is restored • Loop diuretics (Furosemide) • Bisphosphonates • Zoledronic Acid 4 mg IV over 30 minutes • Pamidronate 60-90 mg IV over 2-4 hours • Onset of action is 1-3 days • Dialysis

  41. Magnesium (Mg) • Part of the inseparable trio (K, Ca, Mg) • Hypomagnesemia needs to be corrected to facilitate correction of other electrolytes • 1g Mg = increase in 0.1 mmol/L • Target 1.0 mmol/L in Cardiac patients • Target 0.8 mmol/L in Renal patients • E.g. post-MI patient with Mg 0.6 mmol/L • MgSO4 4g in D5W 250 cc x 24h

  42. Liver enzymes and bilirubins • Prothrombin time • Albumin • TB, DB, IB • Elevated DB = Cholestatic • Elevated IB = Hemolytic • Both could be elevated in liver failure • AST and ALT • NOT liver function test • Help estimate amount of liver parenchymal damage • Hundreds to Thousands: Toxic, Viral, Ischemic • AST: ALT ratio > 2:1, likely alcoholic

  43. Lipid profile • Total Cholesterol (>200 mg/dL) • Statin • HDL (<40 mg/dL in males, < 50 mg/dL in females) • Nicotinic Acid • Statin • LDL (> 150 mg/dL) • Statin • Triglycerides (> 150 mg/dL) • Fibrate (fenofibrate) • Statin

  44. Urinalysis

  45. Urinalysis • pH • Specific gravity • Albumin • Glucose • WBC • RBC • Casts • Crystals • Epithelials

  46. Urinalysis • pH • Important in drug excretion • E.g. Methamphetamines eliminated with acidic pH • Specific gravity • If ≤1.010: hydrated vs inability to concentrate • If ≥ 1.020: dehydrated vs compensation by concentration • Albumin • Glucose

  47. Urinalysis • Albumin • Related to the integrity of the basement membrane • Albuminuria: infection, nephrotic syndrome/kidney disease • Glucose • Non-specific • May be elevated in diabetes

  48. Urinalysis • Epithelials • Used to gauge urine catch • If < 5: “clean catch” • WBC • If > 5: infection in the presence of a clean catch • RBC • If > 5: suspect kidney injury (hematuria? Nephritis? Infection?)

  49. Urinalysis • Casts • WBC casts: pyelonephritis or allergic interstitial nephritis • RBC casts: hematuria • Broad casts: chronic kidney disease • Crystals • Very non-specific • Even “uric acid crystals” are seen in normal patients

  50. Arterial Blood Gas

More Related