Acidosis definition

Routine monitoring of lactate is not recommended, since lactate concentrations do not correlate with symptoms and patients may have asymptomatic lactatemia. Furthermore, technical difficulties in blood collection and processing, and the lack of a standardized definition of lactic acidosis for patients taking NRTIs, prevent any routine monitoring recommendations in the absence of symptoms. In addition, it is possible that NRTIs also cause other forms of mitochondrial dysfunction. 

Tubular acidosis is primary (an isolated inherited metabolic disorder) or secondary (a metabolic disorder associated with inherited or acquired lesions). It is characterized by the inability to maintain normal blood pH as a result of interference with bicarbonate reabsorption or a defect in renal hydrogen excretion. By definition, glomerular filtration is not altered in renal tubular acidosis. 

The acidosis occurring secondary to infusion of crystalline amino acid mixtures need not be serious. Once it is recognized, it can readily be treated with sodium bicarbonate or by the addition of lactate or acetate to the infusate. Reformulation of the amino acid mixtures so as to avoid using the hydrochloride salts will definitively solve this problem. This modification is technically feasible and hopefully will be instituted by the manufacturers. 

The disorders of isoleucine and valine metabolism are detected in a sequential process that begins with the evaluation of the symptoms and signs displayed by the patient. Clinical chemistry is helpful in the assessment of ketogenesis by urinary tests for ketones or quantification of 3-hydroxybuty-rate and acetoacetate in the blood. The electrolytes and pH may provide evidence of acidosis and it is important to assess the presence or absence of hyperammonemia. Amino acid analysis of the plasma and urine may be helpful. In virtually all instances the definitive diagnosis will come from organic acid analysis of the urine. 

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