[Chest radiograph of atypical pneumonia: comparison among Chlamydia pneumoniae. Pneumonia, ornithosis, and Mycoplasma pneumoniae pneumonia]

Clinical analysis of severe Chlamydia psittaci pneumonia: Case series study

The clinical characteristics and diagnosis of ten cases with severe Chlamydia psittaci pneumonia were analyzed. Ten patients had high fever, cough, or diarrhea, and all had a history of contact with birds or poultry. The white blood cell count of the patients was normal or slightly increased. The percentage of neutrophils (N%) and C reactive protein of the patients were significantly increased. Chest computer tomography showed patchy consolidation of both lungs, with one-sided lung lobes prominent, and bronchial inflation signs. All the patients were admitted to the intensive care unit due to respiratory failure. Nine patients needed ventilator-assisted ventilation therapy, and one patient needed high-flow oxygen therapy. All patients had sepsis, and five patients developed septic shock. The patients were diagnosed with severe C. psittaci pneumonia by clinical manifestations and contact history. After timely adjustment of tetracycline-based treatment, eight patients recovered and were discharged, and two patients died of septic shock and respiratory failure. Patients with poultry contact should be cautious toward C. psittaci pneumonia. A better method for the detection of C. psittaci is metagenomic next-generation sequencing. Its examination can shorten the diagnosis time. In a later stage, large-sample research is needed to guide clinical diagnosis and treatment.

Prostatitis as initial manifestation of Chlamydia psittaci pneumonia diagnosed by metagenome next-generation sequencing: A case report

Chlamydia psittaci (C. psittaci) pneumonia is a zoonotic infectious disease caused by C. psittaci, which is often underdiagnosed. The application of metagenomic next-generation sequencing (mNGS) provides an unbiased method for the detection of unknown pathogens. A 46-year-old man received empirical treatment with piperacillin-tazobactam and moxifloxacin after an initial diagnosis of prostatitis and pneumonia. However, he experienced recurrent symptoms and a cough, and a chest computed tomography (CT) showed aggravated pulmonary inflammation. Upon further questioning, the patient recalled a history of contact with pigeons, and a bronchoscope alveolar lavage fluid analysis with mNGS suggested C. psittaci infection. Following treatment with doxycycline, the patient's symptoms were rapidly alleviated, and chest CT showed pulmonary lesions absorption. The patient was followed up for 1 month without any discomfort. This case highlights that initial manifestations of C. psittaci pneumonia may present with atypical symptoms such as prostatitis. Furthermore, mNGS can be a useful tool for the detection of rare or unknown pathogens such as C. psittaci.

Gestational Psittacosis With Secondary Hemophagocytic Syndrome: A Case Report and Literature Review

Gestational psittacosis and hemophagocytic syndrome (HPS) are rare clinical diseases. In this article, a case of gestational psittacosis concomitant with secondary HPS was reported. An analysis was performed on the clinical characteristics, signs, laboratory findings, progression, diagnosis, and treatment of a patient with gestational psittacosis concomitant with secondary HPS. Besides, the literature with respect to this disease was reviewed. This patient was definitively diagnosed through metagenomic next-generation sequencing techniques, bone marrow puncture and smear examination, and the determination of sCD25 level and natural killer (NK) cell activity. Anti-infectives such as doxycycline and etoposide combined with hormone chemotherapy achieved significant improvement in cough and expectoration, a return to normal temperature, and a significant improvement in oxygenation index. In addition, chest computed tomography revealed obvious absorption of lung lesions and a return of NK cell activity and sCD25 levels to normal ranges. Chlamydia psittaci pneumonia requires a clear determination of etiology, while HPS requires bone marrow puncture and smear examination, together with the determination of sCD25 level and NK cell activity in the blood. The findings of this study suggest that metagenomic next-generation sequencing is an effective instrument in clearly identifying pathogens that cause lung infection. Clinicians should consider atypical pathogens of lung infection in patients with poor response to empirical anti-infectives, and strive to design an effective treatment strategy as per an accurate diagnosis based on the etiology. As for patients suffering from long-term high fever and poor temperature control after broad-spectrum antibiotic treatment, non-infectious fever should be taken into account. A rapid and clear diagnosis would significantly improve patient prognosis.

Pneumonia in the immunocompetent patient

Pneumonia is an acute inflammation of the lower respiratory tract. Lower respiratory tract infection is a major cause of mortality worldwide. Pneumonia is most common at the extremes of life. Predisposing factors in children include an under-developed immune system together with other factors, such as malnutrition and over-crowding. In adults, tobacco smoking is the single most important preventable risk factor. The commonest infecting organisms in children are respiratory viruses and Streptoccocus pneumoniae. In adults, pneumonia can be broadly classified, on the basis of chest radiographic appearance, into lobar pneumonia, bronchopneumonia and pneumonia producing an interstitial pattern. Lobar pneumonia is most commonly associated with community acquired pneumonia, bronchopneumonia with hospital acquired infection and an interstitial pattern with the so called atypical pneumonias, which can be caused by viruses or organisms such as Mycoplasma pneumoniae. Most cases of pneumonia can be managed with chest radiographs as the only form of imaging, but CT can detect pneumonia not visible on the chest radiograph and may be of value, particularly in the hospital setting. Complications of pneumonia include pleural effusion, empyema and lung abscess. The chest radiograph may initially indicate an effusion but ultrasound is more sensitive, allows characterisation in some cases and can guide catheter placement for drainage. CT can also be used to characterise and estimate the extent of pleural disease. Most lung abscesses respond to medical therapy, with surgery and image guided catheter drainage serving as options for those cases who do not respond.

Chlamydia pneumoniae: comparison with findings of Mycoplasma pneumoniae and Streptococcus pneumoniae at thin-section CT

PURPOSE

To retrospectively compare thin-section computed tomographic (CT) findings of Chlamydia pneumoniae pneumonia with those of Streptococcus pneumoniae pneumonia and Mycoplasma pneumoniae pneumonia.

MATERIALS AND METHODS

Institutional review board and patient informed consent were not required. Twenty-four patients with C pneumoniae pneumonia (17 men, seven women; age range, 19-89 years) underwent thin-section CT; 41 patients with S pneumoniae pneumonia (28 men, 13 women; age range, 19-91 years) and 30 patients with M pneumoniae pneumonia (20 men, 10 women; age range, 16-67 years) were also enrolled. Thin-section CT scans of each patient were retrospectively and independently assessed by two chest radiologists for consolidation, ground-glass opacity (GGO), bronchovascular bundle thickening, nodules, pleural effusion, lymphadenopathy, reticular or linear opacity, airway dilatation, pulmonary emphysema, and bilateral lung involvement. Consensus was reached for disagreements. The frequency of each finding was compared among the three types of pneumonia by using the chi2 test.

RESULTS

For C pneumoniae pneumonia, CT demonstrated consolidation in 20 patients, GGO in 13, bronchovascular bundle thickening in 17, nodules in 18, pleural effusion in six, lymphadenopathy in eight, reticular or linear opacity in 15, airway dilatation in nine, pulmonary emphysema in 11, and bilateral lung involvement in 12. Bronchovascular bundle thickening (P = .022) and airway dilatation (P = .034) were significantly more frequent in patients with C pneumoniae pneumonia than in those with S pneumoniae pneumonia. Reticular or linear opacity (P = .017), airway dilatation (P = .016), and associated pulmonary emphysema (P = .003) were significantly more frequent in patients with C pneumoniae pneumonia than in those with M pneumoniae pneumonia.

CONCLUSION

C pneumoniae pneumonia demonstrates a wide spectrum of thin-section CT findings that are similar to those of S pneumoniae pneumonia and M pneumoniae pneumonia; airway dilatation and bronchovascular thickening were significantly more frequent in patients with C pneumoniae pneumonia.