acid-base disorder
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Introduction
Systematic approach:
- What is the primary disturbance?
- Is the compensation appropriate?
- What is the anion gap?
- Is the change in anion gap equal to the change in [[[A18927|HCO3-]]]?
Classification
- acidosis: pH < 7.37
- metabolic acidosis: [[[A18927|HCO3-]]] < 22 meq/L
- respiratory acidosis: PaCOs > 44 mm Hg
- alkalosis: pH > 7.44
- metabolic alkalosis: [[[A18927|HCO3-]]] > 26 meq/L
- respiratory alkalosis: PaCO2 < 36 mm Hg
Interpretation
- when the primary disturbance is a metabolic acidosis, the anion gap indicates the presence of unmeasured anions
- when the primary disturbance is other than metabolic acidosis, an increased anion gap reveals a hidden metabolic acidosis
- a narrow anion gap suggests unexpected cations (i.e. immunoglobulins in multiple myeloma)
- provides estimate of urinary ammonium excretion
- urine ammonium is ~ 1/2 of the urine osmolal gap
- patients with kidney defect have urine ammonium < 30 meq/L
- patients with extrarenal losses of bicarbonate have urine ammonium > 80 meq/L
More general terms
More specific terms
- metabolic acidosis
- metabolic alkalosis
- mixed acid-base disorder
- respiratory acidosis; hypercapnic acidosis
- respiratory alkalosis
Additional terms
References
- ↑ Medical Knowledge Self Assessment Program (MKSAP) 14, 16, 18. American College of Physicians, Philadelphia 2006, 2012, 2018.
Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022 - ↑ Gennari FJ, Weise WJ. Acid-base disturbances in gastrointestinal disease. Clin J Am Soc Nephrol. 2008 Nov;3(6):1861-8 PMID: https://www.ncbi.nlm.nih.gov/pubmed/18922984
- ↑ Adrogue HJ, Madias NE. Secondary responses to altered acid-base status: the rules of engagement. J Am Soc Nephrol. 2010 Jun;21(6):920-3. PMID: https://www.ncbi.nlm.nih.gov/pubmed/20431042
- ↑ Berend K et al Physiological Approach to Assessment of Acid-Base Disturbances. N Engl J Med 2014; 371:1434-1445. October 9, 2014 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/25295502 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMra1003327
- ↑ Seifter JL. Integration of acid-base and electrolyte disorders. N Engl J Med. 2014 Nov 6;371(19):1821-31. PMID: https://www.ncbi.nlm.nih.gov/pubmed/25372090
- ↑ Palmer BF, Clegg DJ Electrolyte and Acid-Base Disturbances in Patients with Diabetes Mellitus. N Engl J Med 2015; 373:548-559. August 6, 2015 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/26244308 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMra1503102
- ↑ Madias NE. Renal acidification responses to respiratory acid-base disorders. J Nephrol. 2010 Nov-Dec;23 Suppl 16:S85-91. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21170892
- ↑ Raimondi GA et al Acid-base patterns in acute severe asthma. J Asthma. 2013 Dec;50(10):1062-8. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23947392
- ↑ Seifter JL, Chang HY. Disorders of Acid-Base Balance: New Perspectives. Kidney Dis (Basel). 2017 Jan;2(4):170-186. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/28232934 Free PMC Article