Orbital and intracranial Nocardia farcinica infection caused by trauma to the orbit: a case report
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Localized `and disseminated Nocardia farcinica infection is frequently reported in immunocompromised patients. However, orbital nocardiosis is rare, and, to our knowledge, traumatic orbital nocardiosis that affects the brain has never been described. Here, we report a case of traumatic orbital and intracranial N. farcinica infection in an immunocompetent patient.
A 35-year-old man, who was immunocompetent, to the best of our knowledge and as per the absence of immunodeficiency symptoms, with orbital trauma caused by the penetration of a rotten bamboo branch developed lesions in the orbit and brain. Subsequently, he underwent debridement and received broad-spectrum antibiotic therapy, but orbital infection occurred, with drainage of pus through the sinus tract. The patient then underwent endoscope-assisted local debridement. Bacterial culture of the sinusal pus was positive for N. farcinica, and a combined intracranial infection had developed. The disease was treated effectively by trimethoprim-sulfamethoxazole and ceftriaxone sodium therapy. The patient remained infection free and without complications at the 14-month follow-up.
Traumatic orbital and intracranial infection caused by N. farcinica is a rare infectious disease, and atypical presentations easily lead to misdiagnosis. When a patient presents with an atypical orbital infection that is unresponsive to empirical broad-spectrum antibiotics, along with suspicious neurologic symptoms, Nocardia infection should be considered. Identification by bacterial culture is the gold standard. Complete local debridement and appropriate antibiotic treatment are keys to the treatment of the disease.
KeywordsAntibiotic therapy Endoscope Local debridement Nocardia farcinica Orbital infection Trauma
Magnetic resonance imaging
Nocardia farcinica infection is rare and often occurs in immunocompromised patients and is especially attributable to the respiratory tract or traumatic wounds . N. farcinica infection caused by injuries occurs most commonly in the limbs and skin . Orbital infection due to orbital trauma is uncommon. To our knowledge, orbital nocardiosis with brain infection has never been described. Here, we report a case of orbital and intracranial N. farcinica infection caused by trauma to the orbit in an immunocompetent man.
After 1 week of ceftazidime and metronidazole therapy and orbital surgical treatment, the patient was transferred to the infection department and immediately treated with oral trimethoprim-sulfamethoxazole (4 g every 12 h) and intravenous mannitol (25 g every 12 h). MRI of the head, chest, and abdomen showed no abnormalities. A lumbar puncture yielded clear cerebrospinal fluid with leukocytes 480/μL (normal range 0–10/μL, 45% neutrophils and 55% lymphocytes), glucose 1.98 mol/L (normal range 2.8–4.4 mol/L), chloride 118.2 mol/L (normal range 120–132 mol/L), protein 1046 mg/L (normal range 150–450 mol/L mg/L), and a positive Pandy’s test. Five days later, antibiotic therapy with 2 g ceftriaxone sodium every 12 h was initiated.
Discussion and conclusions
N. farcinica is an aerobic, gram-positive, filamentous, ubiquitous, soilborne, and weakly acid-fast bacteria [3, 4]. N. farcinica infections are usually acquired by direct inhalation of contaminated particles from soil or water; however, these infections are also reported to occur after traumatic injury [5, 6]. Misdiagnosis and mistreatment of N. farcinica infection can cause severe damage and even death, because Nocardia species can disseminate and are resistant to antibiotics.
Nocardiosis often affects immunocompromised individuals. The patient in this case had no obvious immunodeficiency and was infected due to traumatic orbital injury. Infection by direct orbital injury is rare, as most injury-mediated infections occur in the limbs and skin . According to Torres et al., a literature review of nocardiosis showed that traumatic injuries accounted for only 10% of infections . Another review showed that N. farcinica accounted for 5% of all nocardiosis . Additionally, concurrent orbital and intracranial N. farcinica infections due to injury have not been previously reported.
Clinical manifestations of orbital infection usually involve periorbital edema, crepitus, ophthalmoplegia, exophthalmos, chemosis, and visual loss [2, 7]. The case we have reported here had no other specific features, and the symptoms mentioned above are similar to those for subacute local infection. However, the infection in our patient also involved the brain, and the patient experienced high fever and headache. Nocardiosis often disseminates hematogenously to distant organs, such as the lungs, kidneys, joints, and bones . In our patient, the infection did not spread to other organs, possibly because he was young and immunocompetent.
Thus far, isolation and identification of Nocardia strains is the only reliable diagnostic method. Nocardia species are strictly aerobic and grow slowly at 35 °C in standard culture medium. Hence, it is important to inform the microbiological laboratory that nocardiosis with soil/environmentally contaminated penetrating traumas should be considered, even among immunocompetent patients, to facilitate the identification of Nocardia species. N. farcinica grew from cultures of conjunctival pus samples from our patient. Bacteria were not detected in cultures from other body fluids, including orbital abscess secretions, cerebrospinal fluid, and blood, most likely due to the antibiotic therapy. Microscopic examination of Nocardia revealed that these are gram-positive, thin, branching, filamentous, bacillary, or coccoid bacteria . Identification procedures include biochemical, chemotaxonomic, serological, antimicrobial susceptibility testing, and molecular methods. Molecular techniques are more rapid and precise than other methods . In our case, N. farcinica presented as bacillary or coccoid forms, and bacterial identification was performed using an emerging molecular technique, namely matrix-assisted laser desorption ionization-time of flight mass spectrometry, which is a rapid, sensitive, and economical method for identifying and diagnosing microbial infections .
Complete local debridement and appropriate antibiotic therapy are important in the treatment of Nocardia infections . The infectious lesion was located deep within the orbit, making its exposure difficult. As such, endoscope-assisted debridement was important for excising the abscesses efficiently and accurately. Appropriate antibiotic administration is another critical factor to treat nocardiosis, and susceptibility testing is of vital importance as the susceptibility pattern of Nocardia species is highly variable. In our case, drug susceptibility test was not performed, because this was the first case of nocardia infection in our hospital, and paper diffusion method reference standard for the drug susceptibility test on Clinical and Laboratory Standards Institute is not available. However, patients must undergo antibiotic therapy immediately after the diagnosis of N. farcinica infection. Trimethoprim-sulfamethoxazole is the first choice for the treatment of N. farcinica infections before obtaining the susceptibility-test result [1, 4]. Empiric combination therapy of trimethoprim-sulfamethoxazole and ceftriaxone is also recommended . The therapy needs to be continued for several months due to the high possibility of infection recurrence, which depends on the immune status of the patient. If the central nervous system is affected, the therapy should be continued at least for 6 months. In our case, the patient was immunocompetent and was treated with antibiotic therapy for 3 months, and there was no recurrence of infection at 14-month follow-up.
In conclusion, due to the low incidence of orbital Nocardia infections, these are not well characterized and are often not considered in an initial diagnosis. When a patient presents with an atypical orbital infection that is unresponsive to empirical broad-spectrum antibiotics, along with suspicious neurologic symptoms, Nocardia infection should be considered. Misdiagnosis and inappropriate therapy may result in serious consequences. The present case also highlights the clinical features, diagnosis, and novel management of Nocardia infection using endoscope-assisted local debridement. Appropriate antibiotic treatment based on susceptibility testing is another critical component of the treatment for N. farcinica infections.
AAW, QHX, and HFL wrote the manuscript and reported the case to the regulatory agency. YHW followed the patient regularly. All authors read and approved the final manuscript.
The author(s) received no financial support for the research, authorship, and/or publication of this article.
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Written informed consent was obtained from the patient of this case report. A copy of the written consent is available for review by the Editor of this journal.
The author(s) declare that they have no competing interests.
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