← Back to Session

Time Completed: 01:42:54

Final Score 86%

154
26

Questions

  • Q1. Correct
  • Q2. Correct
  • Q3. Correct
  • Q4. Correct
  • Q5. Correct
  • Q6. Correct
  • Q7. X Incorrect
  • Q8. Correct
  • Q9. Correct
  • Q10. X Incorrect
  • Q11. Correct
  • Q12. Correct
  • Q13. X Incorrect
  • Q14. Correct
  • Q15. Correct
  • Q16. Correct
  • Q17. Correct
  • Q18. Correct
  • Q19. Correct
  • Q20. Correct
  • Q21. Correct
  • Q22. Correct
  • Q23. Correct
  • Q24. Correct
  • Q25. Correct
  • Q26. Correct
  • Q27. Correct
  • Q28. Correct
  • Q29. Correct
  • Q30. Correct
  • Q31. Correct
  • Q32. Correct
  • Q33. Correct
  • Q34. Correct
  • Q35. Correct
  • Q36. Correct
  • Q37. Correct
  • Q38. Correct
  • Q39. Correct
  • Q40. Correct
  • Q41. Correct
  • Q42. Correct
  • Q43. Correct
  • Q44. Correct
  • Q45. Correct
  • Q46. X Incorrect
  • Q47. X Incorrect
  • Q48. X Incorrect
  • Q49. X Incorrect
  • Q50. Correct
  • Q51. Correct
  • Q52. Correct
  • Q53. Correct
  • Q54. X Incorrect
  • Q55. X Incorrect
  • Q56. Correct
  • Q57. Correct
  • Q58. Correct
  • Q59. Correct
  • Q60. Correct
  • Q61. X Incorrect
  • Q62. Correct
  • Q63. Correct
  • Q64. Correct
  • Q65. Correct
  • Q66. Correct
  • Q67. Correct
  • Q68. Correct
  • Q69. Correct
  • Q70. Correct
  • Q71. Correct
  • Q72. Correct
  • Q73. Correct
  • Q74. Correct
  • Q75. X Incorrect
  • Q76. Correct
  • Q77. Correct
  • Q78. Correct
  • Q79. Correct
  • Q80. Correct
  • Q81. Correct
  • Q82. X Incorrect
  • Q83. Correct
  • Q84. Correct
  • Q85. Correct
  • Q86. Correct
  • Q87. Correct
  • Q88. Correct
  • Q89. Correct
  • Q90. Correct
  • Q91. Correct
  • Q92. Correct
  • Q93. Correct
  • Q94. X Incorrect
  • Q95. Correct
  • Q96. X Incorrect
  • Q97. Correct
  • Q98. Correct
  • Q99. Correct
  • Q100. Correct
  • Q101. X Incorrect
  • Q102. Correct
  • Q103. Correct
  • Q104. Correct
  • Q105. Correct
  • Q106. Correct
  • Q107. X Incorrect
  • Q108. X Incorrect
  • Q109. Correct
  • Q110. Correct
  • Q111. Correct
  • Q112. X Incorrect
  • Q113. Correct
  • Q114. X Incorrect
  • Q115. Correct
  • Q116. Correct
  • Q117. X Incorrect
  • Q118. Correct
  • Q119. Correct
  • Q120. Correct
  • Q121. Correct
  • Q122. X Incorrect
  • Q123. Correct
  • Q124. X Incorrect
  • Q125. Correct
  • Q126. Correct
  • Q127. Correct
  • Q128. Correct
  • Q129. Correct
  • Q130. Correct
  • Q131. Correct
  • Q132. Correct
  • Q133. Correct
  • Q134. Correct
  • Q135. Correct
  • Q136. Correct
  • Q137. Correct
  • Q138. Correct
  • Q139. Correct
  • Q140. Correct
  • Q141. Correct
  • Q142. Correct
  • Q143. Correct
  • Q144. Correct
  • Q145. Correct
  • Q146. Correct
  • Q147. Correct
  • Q148. Correct
  • Q149. Correct
  • Q150. Correct
  • Q151. Correct
  • Q152. X Incorrect
  • Q153. Correct
  • Q154. Correct
  • Q155. Correct
  • Q156. Correct
  • Q157. X Incorrect
  • Q158. Correct
  • Q159. Correct
  • Q160. Correct
  • Q161. Correct
  • Q162. Correct
  • Q163. Correct
  • Q164. Correct
  • Q165. X Incorrect
  • Q166. Correct
  • Q167. Correct
  • Q168. Correct
  • Q169. Correct
  • Q170. Correct
  • Q171. X Incorrect
  • Q172. Correct
  • Q173. Correct
  • Q174. Correct
  • Q175. Correct
  • Q176. Correct
  • Q177. Correct
  • Q178. Correct
  • Q179. Correct
  • Q180. Correct

Physiology

Renal

Question 37 of 180

You are calculating the anion gap of an unconscious patient with a metabolic acidosis. Which of the following anions are required to calculate the anion gap:

Answer:

The anion gap can be calculated as: ([Na+] + [K+]) - ([Cl-] + [HCO3-]). The normal anion gap is normally between about 6 - 16 mmol/L.

Definition

The anion gap is the difference between the measured cations and the measured anions in plasma. As plasma is always electrically neutral, the anion gap determines the presence of unmeasured anions. These are usually proteins, organic acids, sulphate and phosphate.

The anion gap can be calculated as: ([Na+] + [K+]) - ([Cl-] + [HCO3-])

The normal anion gap is normally between about 6 - 16 mmol/L.

Clinical Relevance

In metabolic acidosis:

  • An increased anion gap occurs if a new acid is added to the body. This dissociates producing free H+ (which uses up bicarbonate) and anions (which take the place of the bicarbonate).
  • A normal anion gap occurs if there is a simple loss of bicarbonate. This causes a compensatory rise in plasma chloride concentration so the anion gap is normal (thus is sometimes referred to as hyperchloraemic acidosis).

Causes of Increased Anion Gap Metabolic Acidosis

MUDPILES can be used to remember some of the causes of a raised anion gap acidosis:

  • Methanol
  • Uraemia (in renal failure)
  • Diabetic ketoacidosis
  • Propylene glycol overdose
  • Infection/Iron overdose/Isoniazid/Inborn errors of metabolism
  • Lactic acidosis
  • Ethylene glycol overdose
  • Salicylate overdose

Causes of Normal Anion Gap Metabolic Acidosis

FUSEDCARS can be used to remember some of the causes of a normal anion gap acidosis:

  • Fistula (pancreaticoduodenal)
  • Ureteroenteric conduit
  • Saline administration
  • Endocrine (hyperparathyroidism)
  • Diarrhoea
  • Carbonic anhydrase inhibitors (e.g. acetazolamide)
  • Ammonium chloride
  • Renal tubular acidosis
  • Spironolactone

Report A Problem

Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.

Loading Form...

Close
  • Biochemistry
  • Blood Gases
  • Haematology
Biochemistry Normal Value
Sodium 135 – 145 mmol/l
Potassium 3.0 – 4.5 mmol/l
Urea 2.5 – 7.5 mmol/l
Glucose 3.5 – 5.0 mmol/l
Creatinine 35 – 135 μmol/l
Alanine Aminotransferase (ALT) 5 – 35 U/l
Gamma-glutamyl Transferase (GGT) < 65 U/l
Alkaline Phosphatase (ALP) 30 – 135 U/l
Aspartate Aminotransferase (AST) < 40 U/l
Total Protein 60 – 80 g/l
Albumin 35 – 50 g/l
Globulin 2.4 – 3.5 g/dl
Amylase < 70 U/l
Total Bilirubin 3 – 17 μmol/l
Calcium 2.1 – 2.5 mmol/l
Chloride 95 – 105 mmol/l
Phosphate 0.8 – 1.4 mmol/l
Haematology Normal Value
Haemoglobin 11.5 – 16.6 g/dl
White Blood Cells 4.0 – 11.0 x 109/l
Platelets 150 – 450 x 109/l
MCV 80 – 96 fl
MCHC 32 – 36 g/dl
Neutrophils 2.0 – 7.5 x 109/l
Lymphocytes 1.5 – 4.0 x 109/l
Monocytes 0.3 – 1.0 x 109/l
Eosinophils 0.1 – 0.5 x 109/l
Basophils < 0.2 x 109/l
Reticulocytes < 2%
Haematocrit 0.35 – 0.49
Red Cell Distribution Width 11 – 15%
Blood Gases Normal Value
pH 7.35 – 7.45
pO2 11 – 14 kPa
pCO2 4.5 – 6.0 kPa
Base Excess -2 – +2 mmol/l
Bicarbonate 24 – 30 mmol/l
Lactate < 2 mmol/l

Join our Newsletter

Stay updated with free revision resources and exclusive discounts

©2017 - 2024 MRCEM Success