Treatment of failure to thrive should focus on identifiable diseases and be limited to interventions that have few risks for these frail patients. Failure to thrive commonly occurs near the end of a person’s life, so the potential benefits of treatment should be considered before evaluations and treatments are undertaken. 5 Initially, treatment involves efforts to modify possible causes. A team approach that includes a dietitian, a speech therapist, a social worker, a mental health professional, and a physical therapist may be helpful. 3 Figure 2 24 offers an algorithmic approach to the diagnosis and management of elderly patients with failure to thrive.
High anion gap metabolic acidosis in this population results from chronic kidney disease, type A lactic acidosis caused by tissue hypoxia, and type B lactic acidosis.( 47 ) Type B lactic acidosis presents with markedly elevated blood lactate levels, possibly caused by drug-induced mitochondrial dysfunction. Affected patients show no evidence of hypoxemia, tissue hypoperfusion, malignancy, or sepsis. This disorder has been reported with use of nucleoside reverse transcriptase inhibitors such as zidovudine, didanosine, zalcitabine, lamivudine, and stavudine.( 48 ) Although life-threatening acidosis is rare, 5-25% of treated patients may develop mildly elevated lactate levels (-5 mmol/L) without acidosis. The value of screening and the predictive value of small, asymptomatic elevations in lactate are unknown.( 48,49 ) Routine monitoring for hyperlactatemia with lactic acid levels is not recommended, but lactic acid levels should be measured in patients who present with low bicarbonate levels, an elevated anion gap, or abnormal liver enzymes.( 50 )