b. A 35 year old female with AIDS is brought into the Emergency Department with
ID: 257370 • Letter: B
Question
b. A 35 year old female with AIDS is brought into the Emergency Department with a fever of 39oC ad a three month history of copious diarrhea. On physical exam, the patient is a thin female with moderate distress. Vital signs are blood pressure (100/60), pulse 100, and respiratory rate of 18. Na+ 136 K+ 3.4 Cl--112 BUN 30 Slu 105 HCO3-: 14 pH 7.35 Paco2 27 Pao2 90 HCO3- 14 Review the case and list the critical concerns for this patient (her K+ is low). What acid/base disturbance would you expect to see with this patient based on the physical exam? (3 pts) i. ii. Complete the acid/base workup. (4 pts) ii. Calculate the anion gap and the delta ratio (2 pts) iv. Summarize your findings. (4 pts)Explanation / Answer
Answer to i.
The acid base disturbance in the give patient may be attributed to Copious Diarrhea which lead to Loss of Potassium, Loss of bicarbonate, fluid loss leading to volume depletion
As there is loss of bicarbonate, it resulted in Metabolic acidosis as it is evident from the data where pH is low (7.35) and bicarbonate levels (14) are low
Answer to ii. Complete the acid/base work up
Reduces
(7.35)
Normal value 7.4-7.5
Decreased
(27)
Normal 35-45
Urine ammonium excretion, urinary pH (which will be increased in metabolic acidosis), acid-loading tests, urinary pCO2 test, sodium sulfate, furosemide test can be done for further confirmation of metabolic acidosis
Answer to iii. Calculate the anion gap and the delta ratio
Anion gap is given by the formula:
Sodium level- (Bicarbonate level + Chloride level)
Given that Sodium level = 136, Bicarbonate = 14 and chloride = 112
136- (14+112) = 136-126 = 10
So anion gap in the patient is 10.
Bicarbonate gap = Normal bicarbonate- Bicarbonate level in patient
= 25-14 = 11
Bicarbonate gap in the patient is 11.
Delta ratio = delta anion gap/ delta bicarbonate
= 10/11 = 0.909
Delta ratio of <1 (in this case 0.909) signifies that the condition is Simple NonAnion Gap Metabolic acidosis.
Answer to iv. Summarize your findings
- This is a simple disorder and copious diarrhoea resulted in the metabolic acidosis.
- The Exchange of bicarbonate for chloride is the operative mechanism responsible for this condition of Non anion gap metabolic acidosis
- Kussmals respiration can be seen during physical findings
- Compensatory mechanisms include Hyperventilation, acidosis stimulated the respiratory center in medulla, pCO2 is the index of alveolar ventilation
- Treatment include administration of alkali, Vitamin D, Potassium supplements, bicarbonates etc for correcting the Metabolic acidosis.
- As the patient is suffering from AIDS, opportune microbes like E.coli would have resulted in diarrhoea and antibiotic therapy is recommended to combat the microbe as there is immune suppression in the patient
Condition pH Caused by pCO2 pHCO3- Buffer system Respiratory function for compensation Renal function for compensation Metabolic acidosisReduces
(7.35)
Normal value 7.4-7.5
Severe dehydration, Dirrhoea, vomiting, renal failure, diabetes mellitusDecreased
(27)
Normal 35-45
Decreased HCO3-/H2C03 Hyperventilation leadint to increase in excretion of H2C03 as CO2 Increase in acid excretion by Na+/H+ exchange, increase in NH3 formation and HCO3- reabsorptionRelated Questions
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