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INTERACTIVE CASE DISCUSSION. Acid-Base Disorders (Part I). Acid-Base Disorders (Part I). CASE #1: 24 y/o male with insulin-dependent diabetes mellitus 2 day history of fever and diarrhea BP=80/60, PR = 120/min, RR= 35/min,T = 39 C Dry mucous membranes, poor skin turgor, flat neck veins
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INTERACTIVE CASE DISCUSSION Acid-Base Disorders (Part I)
Acid-Base Disorders (Part I) CASE #1: • 24 y/o male with insulin-dependent diabetes mellitus • 2 day history of fever and diarrhea • BP=80/60, PR = 120/min, RR= 35/min,T = 39 C • Dry mucous membranes, poor skin turgor, flat neck veins • Clear breath sounds • Abdomen soft, hyperactive bowel sounds
Acid-Base Disorders (Part I) CASE #1: • Serum Na = 138meq/l • Serum K= 4.2meq/l • Serum Cl= 108meq/l • Serum HCO3 = 10meq/l • Glucose = 350 mg/dl • ABGs: pH = 7.30, pCO2 = 23 mmHg, pO2 = 92 mmHg (room air)
Acid-Base Disorders (Part I) QUESTION #1: What is the acid-base disorder present? • Metabolic acidosis • Metabolic alkalosis • Respiratory acidosis • Respiratory alkalosis
Acid-Base Disorders (Part I) ANSWER #1: Metabolic acidosis ABGs: pH = 7.30 () pCO2 = 23 () HCO3 = 10 () pCO2 = ( 1.5 X HCO3) + 8 = ( 1.5 X 10 ) + 8 = 23 mmHg
Acid-Base Disorders (Part I) QUESTION #2: How will you systematically approach the present acid-base problem?
Acid-Base Disorders (Part I) ANSWER #2:
Acid-Base Disorders (Part I) QUESTION #3: What is the calculated serum anion gap in this case ?
Acid-Base Disorders (Part I) ANSWER #3: Anion gap = Na – (Cl + HCO3) = 138 – (108 + 10) = 138 – 118 = 20 ( Wide gap metabolic acidosis)
Acid-Base Disorders (Part I) QUESTION #4: In general, what are the causes of a wide anion gap metabolic acidosis?
Acid-Base Disorders (Part I) ANSWER #4: Causes of a Wide Gap Metabolic Acidosis • Lactic acidosis • Ketoacidosis: diabetes, alcoholism, starvation • Toxins: salicylates, methanol, ethylene glycol • Renal failure
Acid-Base Disorders (Part I) CASE #1: Other Laboratory Results Serum creatinine = 1 mg/dl Serum ketones = negative Serum lactate = 3 meq/l
Acid-Base Disorders (Part I) QUESTION #5: In this particular patient, what is the cause of the acid-base disorder?
Acid-Base Disorders (Part I) ANSWER #5: Lactic acidosis • No history of toxin ingestion • Normal kidney function • Negative serum ketones • Hypotensive with an elevated serum lactate
Acid-Base Disorders Part II Case #2: • 50 year old female with fever and diarrhea of two days duration • No previous illness; not on any medicines • BP =104/60, HR = 96/minute, RR = 30/min • Clear breath sounds • Hyperactive bowel sounds
Acid-Base Disorders Part II Case #2: • ABGs at RA: pH = 7.30, pCO2 = 20, pO2 = 90, HCO3 = 8 • Serum Na = 140 meq/L • Serum K = 3.6 meq/L • Serum Cl = 124 meq/L • Serum HCO3 = 8 meq/L
Acid-Base Disorders Part II QUESTION #1: What is the acid-base disorder present? • Metabolic acidosis • Metabolic alkalosis • Respiratory acidosis • Respiratory alkalosis
Acid-Base Disorders Part II ANSWER #1: Metabolic acidosis ABGs: pH = 7.30 () pCO2 = 20 () HCO3 = 8 () pCO2 = (1.5 X HCO3) + 8 = (1.5 X 8) + 8 = 20
Acid-Base Disorders Part II QUESTION #2: How will you systematically approach the present acid-base problem?
Acid-Base Disorders Part II QUESTION #3: What is the calculated serum anion gap in this case?
Acid-Base Disorders Part II ANSWER #3: Anion gap = Na – (Cl + HCO3) = 140 – (124 + 8) = 8 ( Normal anion gap metabolic acidosis)
Acid-Base Disorders Part II QUESTION #4: In general, what are the causes of a normal anion gap metabolic acidosis?
Acid-Base Disorders Part II Causes of Normal Gap Metabolic Acidosis • Gastrointestinal Bicarbonate Losses : diarrhea, small bowel drainage, ureterosigmoidostomy, jejunal loop, ileal loop • Renal Bicarbonate Losses : Renal Tubular Acidosis Types I, II and IV • Drugs : K-sparing diuretics, trimethoprim, pentamidine, ACE-I, NSAIDs, cyclosporine • Others: Acid loads, ketosis with ketone excretion, expansion acidosis, hippurate
Acid-Base Disorders Part II • QUESTION #5: In this particular case, what is the cause of the normal anion gap metabolic acidosis?
Acid-Base Disorders Part II ANSWER #5 : • Diarrhea –due to Na and HCO3 losses
Acid-Base Disorders Part III Case # 3: • 65 year old male with nausea and severe vomiting of three days duration • Also with atopic dermatitis on high dose steroids • BP = 90/60, HR= 120/min., RR = 20/min • JVP = 4 cm,dry mucosa, clear breath sounds • Abdomen distended, active bowel sounds • Skin: poor skin turgor, multiple plaques with excoriations
Acid-Base Disorders Part III Case #3: • ABGs at RA: pH = 7.50, pCO2 = 56, pO2 = 92, HCO3 = 42 • Serum Na = 144 meq/L • Serum K = 3.6 meq/L • Serum Cl = 81 meq/L • Serum HCO3 = 42 meq/L • Urine Na = 5 meq/L, Urine Cl = 8 meq/L
Acid-Base Disorders Part III QUESTION #1: What is the acid-base disorder present?
Acid-Base Disorders Part III ANSWER #1: Metabolic alkalosis ABGs: pH = 7.5 () pCO2 = 56 () HCO3 = 42 () pCO2 = 0.75 (HCO3) = 0.75 (14) = 10.5 pCO2 = 45 + 10.5 = 56
Acid-Base Disorders Part III QUESTION #2: How will you systematically approach the present acid-base problem?
Acid-Base Disorders Part III Question #3: In general, what are the causes of metabolic alkalosis?
Acid-Base Disorders Part III ANSWER #3: Causes of Metabolic Alkalosis • Chloride Responsive (Urine Cl < 25): Vomiting, NGT suction, diuretics (late), factitious diarrhea, low Cl intake, posthypercapnia, cystic fibrosis
Acid-Base Disorders Part III • Chloride Resistant (Urine Cl > 45): Primary mineralocorticoid excess, diuretics (early), alkali load, Bartter’s or Gitelman’s syndrome, severe hypokalemia
Acid-Base Disorders Part III QUESTION #4: In this particular case, what is the cause of the metabolic alkalosis?
Acid-Base Disorders Part III ANSWER #4: Vomiting • History of vomiting • Signs of dehydration • Urine chloride = 8 meq/L (< 25), Cl responsive type of metabolic alkalosis