Unknown Renal Impairment: A Rare Case of Inhaled Tobramycin Induced Acute Kidney Injury in a Cystic Fibrosis Patient.

Acute kidney injury is a reversible medical condition commonly caused by nephrotoxic agents. The infrequency that a nebulized medication elicits a renal insult presents a rare diagnostic challenge. Within this case, we report a 57-year-old cystic fibrosis patient with chronic kidney disease (CKD) Stage G3b (baseline 1.5-1.6 mg/dL) who developed an acute kidney injury (AKI) with a serum creatinine elevation to 4.08 mg/dL and associated worsening vestibular dysfunction related to twice-daily nebulized tobramycin inhalation solution (TIS). The patient was found to have a tobramycin serum level of 4.2 µg/mL 2.5 h after TIS dosing, with elevation remaining present at 1.1 µg/mL 24 h after discontinuation of therapy. Laboratory values at one month continued to show elevated creatinine levels at 2.1 mg/dL, suggesting progression of his baseline CKD. This case supports the benefit of obtaining tobramycin serum levels and vestibular/audiology function testing when evaluating patients on chronic nebulized TIS who present with acute or chronic renal dysfunction. From these serum levels, adjustments to daily dosing, regular monitoring of tobramycin serum levels, or discontinuation of treatment should be made to prevent permanent renal damage in patients with CKD. Calculated Naranjo ADR Probability Scale: 9; Definite.

Ethylene glycol intoxication: Disparate findings of immediate versus delayed presentation.

Ethylene glycol is a common household substance responsible for a large number of ingestions in the U.S. each year. In 2001, nearly 5,000 ethylene glycol exposures were reported with more than 1,600 patients requiring medical treatment. There were 16 deaths attributed to ethylene glycol in 2001, second only to ethanol overdose for lethal ingestions. Diagnosis of ethylene glycol ingestion is relatively straight-forward when an individual with a history of exposure is found to have a high anion-gap metabolic acidosis and an elevated osmolar gap. Appropriate treatment can be immediately employed and the diagnosis confirmed by the finding of elevated ethylene glycol levels in the serum. In the absence of exposure history, the differential diagnosis of a high anion-gap metabolic acidosis and an elevated osmolar gap will also lead to consideration of ethylene glycol ingestion. This well-recognized presentation of ethylene glycol toxicity includes findings expected in individuals who present for care soon after their ingestion. A less well-known pattern may be seen in those for whom care is delayed. We present a patient with delayed presentation of ethylene glycol ingestion and review the physiology and biochemistry that underlies this different presentation. Unfortunately, without history or strong laboratory evidence, ethylene glycol ingestion may be easily overlooked in individuals with delayed presentation.