Not All That Infiltrates Is Bacterial: A Case of Pulmonary Nocardiosis
Poster #: 064
Session/Time: A
Author:
Samuel A. Opeke, MS
Mentor:
Cayleigh M. Blumrick, MD
Research Type: Case Report
Abstract
INTRODUCTION:
Nocardia species is an aerobic actinomycete, catalase-positive, gram-positive bacillus, with a partially acid-fast branching filamentous form. Approximately two-thirds of Nocardia infections occur in immunocompromised individuals, with transmission typically through inhalation or cutaneous inoculation. Nocardial infections present insidiously over the course of several weeks, commonly involving the pulmonary, cutaneous, and central nervous systems in disseminated disease.
CASE INFORMATION:
A 43-year-old patient presented to the emergency room with several weeks of dyspnea, fever, cough with productive green sputum, and myalgias. Significant past medical history included a new diagnosis of neurosarcoidosis requiring high-dose steroids for several weeks, hypertension, insulin-dependent diabetes mellitus 2, a history of seizures, and a history of lymphadenopathy demonstrating non-necrotizing granulomatous changes. At initial presentation, this patient was afebrile without leukocytosis or dyspnea at rest. Vital signs were as follows: 98.3°F, blood pressure 103/64, heart rate 103 beats per minute, respirations 16 breaths per minute on room air. A chest CT was taken due to concerns for pneumonia, revealing bilateral nodular and confluent airspace opacities. An MRI revealed diminished leptomeningeal enhancement compared to prior imaging. The patient was admitted and underwent extensive diagnostic evaluation, including respiratory cultures, acid-fast bacilli testing, fungal studies, and bronchoalveolar lavage. Initial empirical therapy included cefepime and vancomycin, later modified based on preliminary results showing Staphylococcus aureus colonization on sputum culture and elevated fungitell levels (>500), suggesting fungal etiology. On hospital day 8, bronchoalveolar lavage cultures yielded Nocardia species, later identified as Nocardia veterana on day 18. The patient remained on combination therapy outpatient, including trimethoprim-sulfamethoxazole, linezolid, and imipenem until sensitivities returned on day 44, where the patient was de-escalated to TMP-SMX as monotherapy. She continued to follow up as an outpatient due to risk of antimicrobial-related adverse effects, including pancytopenia, hepatotoxicity, and nephrotoxicity.
DISCUSSION:
This case demonstrates the diagnostic challenges inherent in nocardiosis, where the broad differential diagnosis includes endemic mycoses, tuberculosis, and other opportunistic infections. Though uncommon, it primarily affects individuals with chronic lung disease or immunocompromising conditions, a growing patient population. This patient presented with risks including iatrogenic immunosuppression from high-dose steroids for neurosarcoidosis, poorly controlled diabetes, and granulomatous changes suggestive of possible inflammatory or immune dysregulation. The gold standard for Nocardia identification is via molecular biology, such as gene sequencing; however, this case illustrates the time-intensive nature of receiving diagnostic results. Nocardiosis management requires multidrug therapy to ensure coverage against the variable susceptibility profiles of different Nocardia species. TMP-SMX, linezolid, and carbapenems have proven effective against disseminated disease. Treatment typically lasts 6 months with extended courses of 9-12 months or longer recommended for disseminated disease or CNS involvement.
CONCLUSION:
Nocardiosis represents a challenging opportunistic infection requiring high clinical suspicion in immunocompromised patients presenting with pulmonary symptoms. Early recognition, appropriate microbiological sampling with prolonged incubation, and multidrug antimicrobial therapy are recommended for successful management outcomes. This case demonstrates the importance of maintaining a broad differential and the time-consuming nature of nocardial diagnostics, emphasizing the need for empiric, multi-antimicrobial therapy in suspected cases while awaiting definitive identification and susceptibility results.
Nocardia species is an aerobic actinomycete, catalase-positive, gram-positive bacillus, with a partially acid-fast branching filamentous form. Approximately two-thirds of Nocardia infections occur in immunocompromised individuals, with transmission typically through inhalation or cutaneous inoculation. Nocardial infections present insidiously over the course of several weeks, commonly involving the pulmonary, cutaneous, and central nervous systems in disseminated disease.
CASE INFORMATION:
A 43-year-old patient presented to the emergency room with several weeks of dyspnea, fever, cough with productive green sputum, and myalgias. Significant past medical history included a new diagnosis of neurosarcoidosis requiring high-dose steroids for several weeks, hypertension, insulin-dependent diabetes mellitus 2, a history of seizures, and a history of lymphadenopathy demonstrating non-necrotizing granulomatous changes. At initial presentation, this patient was afebrile without leukocytosis or dyspnea at rest. Vital signs were as follows: 98.3°F, blood pressure 103/64, heart rate 103 beats per minute, respirations 16 breaths per minute on room air. A chest CT was taken due to concerns for pneumonia, revealing bilateral nodular and confluent airspace opacities. An MRI revealed diminished leptomeningeal enhancement compared to prior imaging. The patient was admitted and underwent extensive diagnostic evaluation, including respiratory cultures, acid-fast bacilli testing, fungal studies, and bronchoalveolar lavage. Initial empirical therapy included cefepime and vancomycin, later modified based on preliminary results showing Staphylococcus aureus colonization on sputum culture and elevated fungitell levels (>500), suggesting fungal etiology. On hospital day 8, bronchoalveolar lavage cultures yielded Nocardia species, later identified as Nocardia veterana on day 18. The patient remained on combination therapy outpatient, including trimethoprim-sulfamethoxazole, linezolid, and imipenem until sensitivities returned on day 44, where the patient was de-escalated to TMP-SMX as monotherapy. She continued to follow up as an outpatient due to risk of antimicrobial-related adverse effects, including pancytopenia, hepatotoxicity, and nephrotoxicity.
DISCUSSION:
This case demonstrates the diagnostic challenges inherent in nocardiosis, where the broad differential diagnosis includes endemic mycoses, tuberculosis, and other opportunistic infections. Though uncommon, it primarily affects individuals with chronic lung disease or immunocompromising conditions, a growing patient population. This patient presented with risks including iatrogenic immunosuppression from high-dose steroids for neurosarcoidosis, poorly controlled diabetes, and granulomatous changes suggestive of possible inflammatory or immune dysregulation. The gold standard for Nocardia identification is via molecular biology, such as gene sequencing; however, this case illustrates the time-intensive nature of receiving diagnostic results. Nocardiosis management requires multidrug therapy to ensure coverage against the variable susceptibility profiles of different Nocardia species. TMP-SMX, linezolid, and carbapenems have proven effective against disseminated disease. Treatment typically lasts 6 months with extended courses of 9-12 months or longer recommended for disseminated disease or CNS involvement.
CONCLUSION:
Nocardiosis represents a challenging opportunistic infection requiring high clinical suspicion in immunocompromised patients presenting with pulmonary symptoms. Early recognition, appropriate microbiological sampling with prolonged incubation, and multidrug antimicrobial therapy are recommended for successful management outcomes. This case demonstrates the importance of maintaining a broad differential and the time-consuming nature of nocardial diagnostics, emphasizing the need for empiric, multi-antimicrobial therapy in suspected cases while awaiting definitive identification and susceptibility results.