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3. The most likely diagnosis is an atypical pneumonia
Naltrexone, an opioid antagonist, is used to treat alcoholism and opioid dependence (1). A diffuse pneumonia has been rarely reported secondary to naltrexone (1). A markedly elevated lactate is usually an ominous finding (2). The normal blood lactate concentration in unstressed patients is 0.5-1 mmol/L. Patients with critical illness can be considered to have normal lactate concentrations of less than 2 mmol/L. Lactate levels above 4 mmol are associated with major metabolic dysregulation, tissue hypoperfusion, the effects of certain drugs or toxins, and congenital abnormalities in carbohydrate metabolism.
Her chest x-ray and CT scan both show diffuse consolidation consistent with an atypical pneumonia. This term usually refers to pneumonia caused by certain bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, Chlamydophila pneumoniae and Chlamydia psittaci (3). It is called “atypical” because the symptoms differ from those of pneumonia due to other common bacteria. Even though it is called atypical, these infections are not uncommon. Influenza is sometime lumped into this group although it is caused a virus. Radiographic findings in atypical pneumonia are often considerably more impressive than the clinical findings.
She was given a dose of 125 mg of methylprednisolone in the emergency department and blood cultures were obtained. She was admitted to the intensive care unit and intubated. Treatment with norepinephrine and dobutamine along with oseltamivir, ceftriaxone, and levofloxacin was begun.
The next morning, she is clinically unchanged although her fever is decreased and her lactate has decreased below 2 mmol. Her blood cultures showed no growth and respiratory viral and bacterial pathogen panels were negative.
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