INTERACTIVE CASE DISCUSSION
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Transcript of INTERACTIVE CASE DISCUSSION
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?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. 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)
W ide Anion Gap(>12)
Norm al Anion Gap(5-11)
Serum Anion G ap(5-11)
M etabolic acidosis
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
INTERACTIVE CASE DISCUSSION
Acid-Base Disorders
(Part II)
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?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. 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?
A c i d - B a s e D i s o r d e r s ( P a r t I I )
W ide Anion Gap(>12)
Norm al Anion Gap(5-11)
Serum Anion Gap(5-11)
M etabolic acidosis
A N S W E R # 2 :
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 AcidosisI. Gastrointestinal Bicarbonate Losses :
diarrhea, small bowel drainage, ureterosigmoidostomy, jejunal loop, ileal loop
II. Renal Bicarbonate Losses : Renal Tubular Acidosis Types I, II and IV
III. Drugs : K-sparing diuretics, trimethoprim, pentamidine, ACE-I, NSAIDs, cyclosporine
IV. 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
INTERACTIVE CASE DISCUSSION
Acid-Base Disorders
(Part III)
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 alkalosisABGs: 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
Cl Responsive(Urine Cl < 25)
Cl Resistant(Urine Cl> 40)
M etabolic alkalosis
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