16

CASE 16


A 29-year-old woman suffered from a dry cough, shortness of breath, and pleuritic chest pain. She continued to have these symptoms for more than a week and subsequently developed fever, chills, and bloody cough.


Two weeks before this episode, the patient had been admitted for treatment of leukemia to a hospital that was in the midst of a major reconstruction project. While hospitalized, she received cytotoxic chemotherapy and developed severe neutropenia, which had persisted to the current presentation.



PHYSICAL EXAMINATION



VS: T 38.9°C, P 114/min, R 36/min, BP 106/62 mmHg

PE: An ill-appearing female in moderate respiratory distress. Bilateral rales over both lungs were heard.


LABORATORY STUDIES



Blood



Hematocrit: 24%

WBC: 1100/μL (leukopenia)

Differential: 5% PMNs (absolute neutrophil count 55), 80% lymphs, 10% monos, 5% blasts

Platelets: 12,000/μL (thrombocytopenia)

Blood gases: pO2 62 mmHg

Serum chemistries: Normal


Imaging


A chest x-ray showed a wedge-shaped lesion in the left lung and a right middle lobe infiltrate (Fig. 16-1). A CT scan revealed small pulmonary nodules and a hazy rim (halo sign) with ground-glass attenuation.


image

FIGURE 16-1 An admission chest film showing bilateral infiltrates in this patient.


(Courtesy of Dr. Paul Southern, Departments of Pathology and Medicine, University of Texas Southwestern Medical Center, Dallas, TX.)



Diagnostic Work-Up


Table 16-1 lists the likely causes of illness (differential diagnosis). Investigational approach may include


• Direct microscopy
• Acid-fast stain, Gram stain of sputum

• Cytology staining and microscopy of bronchoscopic biopsy or sputum using KOH/calcofluor, Giemsa, and silver stain to demonstrate fungal elements

• Fungal cultures

• Serum antigen testing for Aspergillus galactomannan, which (in the appropriate clinical setting) can be useful

• Blood cultures to rule out bacteremia

TABLE 16-1 Differential Diagnosis and Rationale for Inclusion (consideration)






Aspergillosis

Bacterial pneumonia (Pseudomonas aeruginosa, Staphylococcus aureus)

Legionellosis

Nocardiosis

Pneumocystis pneumonia (Pneumocystis jiroveci)

Zygomycosis (e.g., mucor)

Rationale: The clinical scenario described above is highly characteristic for invasive pulmonary aspergillosis in patients with neutropenia. While the other organisms listed can also cause severe pneumonia, the CT findings in this case suggest aspergillosis. Other filamentous fungi, or molds, such as mucor, can also cause similar presentations. Other causes of community-acquired pneumonia, as well as Nocardia, should always be considered in immunocompromised patients.

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Aug 25, 2016 | Posted by in MICROBIOLOGY | Comments Off on 16

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