Hyperchloremic Acidosis During the Recovery Phase of Diabetic Ketosis

Abstract

We have studied 35 patients to find the occurrence of hyperchloremic acidosis during the recovery phase of diabetic ketoacidosis. At admission the patients had typical normochloremic acidosis, with increased anion gap exactly balancing decreased serum bicarbonate. In contrast, in 18 patients with phenformin-induced lactic acidosis, the increase in anion gap at admission was much greater than the decrease in bicarbonate. The difference between lactic acidosis and ketoacidosis may be explained by a slower rate of excretion of lactate than of ketone anions. After the patients with ketoacidosis were treated, the acidosis became predominantly hyperchloremic with normal anion gap. Failure to normalize serum bicarbonate is attributed to excretion of ketone anions in the urine.

Serum Anion Gap

“…(55-57), whereas in others it was greater than 1:1 (54,71) in the absence of apparent coexisting metabolic alkalosis or other hyperbicarbonatemic disorder (range 1.6 to 1.8) (54,57,63,71). This deviation from the 1:1 stoichiometry has been postulated by some to result from a disparity between the rates of entry of protons and lactate anions into cellular compartments (32,70,71), whereby protons are buffered outside the extracellular fluid but the lactate tends to remain within the extracellular fluid compartment.…”

“…Development of renal failure as a result of volume contraction favors the appearance of high anion gap acidosis, whereas preserved glomerular filtration favors the development of normal anion gap acidosis. Pure and mixed patterns of metabolic acidosis can be observed in ketoacidosis (52,62,63). In this regard, an additional factor that contributes to the genesis of a normal anion gap acidosis in this setting is the type and the quantity of replacement fluid administered.…”

Use of the ΔAG/ΔHCO3 − Ratio in the Diagnosis of Mixed Acid-Base Disorders

“…8,10 This relationship is primarily due to the effect of volume status on renal clearance of keto-anions. Lower renal clearance of keto-anion in hypovolemia also explains two other observations: (1) That volume expansion is associated with the development of HCMA, 8,11 and (2) that patients with higher ⌬AG/ ⌬HCO 3 Ϫ ratios on admission have a more rapid rise in bicarbonate generated by metabolism of keto-anions. 8 In summary, the expected stoichiometric relationship seems true only of the mean data, with a wide range for individual patients.…”

“…13 In addition, one should be cautious in applying these rules developed in DKA to patients with other types of metabolic acidosis. Oh et al 11 found a mean ratio close to unity in a group of patients with DKA but as high as 1.6 in patients with phenformin-induced lactic acidosis. This is probably due to the lower renal clearance of lactate compared with keto-anions.…”

Diabetic Ketoacidosis

“…Acute kidney injury leads to accumulation of other unmeasured anions, such as sulphate, urate and phosphate [174]. All these, together with hyperchloremia which predominates during the recovery phase of DKA [175], contribute to the development of acidemia, which often is severe [176,177].…”