37-year-old man • cough • increasing shortness of breath • pleuritic chest pain • Dx?

THE CASE

A 37-year-old man with a history of asthma, schizoaffective disorder, and tobacco use (36 packs per year) presented to the clinic after 5 days of worsening cough, reproducible left-sided chest pain, and increasing shortness of breath. He also experienced chills, fatigue, nausea, and vomiting but was afebrile. The patient had not travelled recently nor had direct contact with anyone sick. He also denied intravenous (IV) drug use, alcohol use, and bloody sputum. Recently, he had intentionally lost weight, as recommended by his psychiatrist.

Medication review revealed that he was taking many central-acting agents for schizoaffective disorder, including alprazolam, aripiprazole, desvenlafaxine, and quetiapine. Due to his intermittent asthma since childhood, he used an albuterol inhaler as needed, which currently offered only minimal relief. He denied any history of hospitalization or intubation for asthma.

During the clinic visit, his blood pressure was 90/60 mm Hg and his heart rate was normal. His pulse oximetry was 92% on room air. On physical examination, he had normal-appearing dentition. Auscultation revealed bilateral expiratory wheezes with decreased breath sounds at the left lower lobe.

A plain chest radiograph (CXR) performed in the clinic (FIGURE 1) showed a large, thick-walled cavitary lesion with an air-fluid level in the left lower lobe. The patient was directly admitted to the Family Medicine Inpatient Service. Computed tomography (CT) of the chest with contrast was ordered to rule out empyema or malignancy. The chest CT confirmed the previous findings while also revealing a surrounding satellite nodularity in the left lower lobe (FIGURE 2). QuantiFERON-TB Gold and HIV tests were both negative.

THE DIAGNOSIS

The patient was given a diagnosis of a lung abscess based on symptoms and imaging. An extensive smoking history, as well as multiple sedating medications, increased his likelihood of aspiration.

DISCUSSION

Lung abscess is the probable diagnosis in a patient with indolent infectious symptoms (cough, fever, night sweats) developing over days to weeks and a CXR finding of pulmonary opacity, often with an air-fluid level.^1-4 A lung abscess is a circumscribed collection of pus in the lung parenchyma that develops as a result of microbial infection.⁴

Primary vs secondary abscess. Lung abscesses can be divided into 2 groups: primary and secondary abscesses. Primary abscesses (60%) occur without any other medical condition or in patients prone to aspiration.⁵ Secondary abscesses occur in the setting of a comorbid medical condition, such as lung disease, heart disease, bronchogenic neoplasm, or immunocompromised status.⁵

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