Gestational psittacosis causes severe pneumonia and miscarriage: A case report and literature review

Abstract

Psittacosis is an uncommon zoonotic illness, and gestational psittacosis is even rarer. The clinical signs and symptoms of psittacosis are varied, often overlooked, and swiftly identified by metagenomic next-generation sequencing. We recorded the case of a 41-year-old pregnant woman with psittacosis where the disease was not detected early on, resulting in severe pneumonia and fetal miscarriage. The clinical symptoms, diagnosis, and treatment of psittacosis in pregnancy are the subject of this case study.

Introduction

Psittacosis is a zoonotic disease caused by the gram-negative, obligate intracellular bacterium Chlamydia psittaci, with birds serving as the primary reservoir [1]. The prevalence of psittacosis is low; a meta-analysis study found that C psittaci causes about 1% of community-acquired pneumonias each year [2]. Clinical features of psittacosis range widely, from asymptomatic to multiorgan failure. Even when adequately treated, missing and misdiagnosed instances by clinicians can occasionally be fatal [1], [3], [4]. The prognosis of people with psittacosis depends heavily on early identification and treatment. Clinicians frequently receive negative results because of the numerous limitations of conventional procedures for C psittaci detection [5]. With the development of mNGS in recent years, which is more sensitive to the diagnosis of uncommon pathogenic microorganisms in clinical practice, we can increase the accuracy of psittacosis diagnosis and decrease delays [6]. This has considerable value in guiding treatment of psittacosis. In 1 case of gestational psittacosis that we have documented, treatment was delayed due to a lack of an early diagnosis, which led to severe pneumonia, multiple organ failure, and fetal mortality.

Case report

Having experienced "fever for 5 days and shortness of breath for 2 days," the patient, a 41-year-old pregnant woman at 16 + 5 weeks, was admitted to the hospital. The patient's peak body temperature was 40.5°C, and despite using ibuprofen as an antipyretic, there was no change. The patient also had no cough and sputum. A chest X-ray revealed that she had lobar pneumonia in the upper right lung, when she was admitted to a nearby hospital. The patient received antipyretic medications from the neighborhood hospital, including acetaminophen, dexamethasone, and cefepime to treat the illness, but the fever continued to return. The patient experienced heart rate, accelerated respiration rate, and cough during hospitalization. The fever persisted after receiving gamma globulin to enhance immunity and switching antibiotics to meropenem and tecolarin. The local hospital collected a blood sample and sent it to the genetic testing platform for mNGS testing because it was unknown what infection was responsible for the fever. That night, the patient was moved to our hospital. The patient had 3 pregnancies, 2 births, and was previously in good health. On admission to our hospital, the patient had the following vital signs: T 38.0°C, R 32, P 140, BP 109/67 mmHg, and oxygen saturation 89% (4L/min oxygen flow). Both lower limbs were swollen, and pulmonary auscultation revealed coarse breath sounds in both lungs as well as pronounced wet rales. No other systemic abnormalities were seen. After admission, a blood gas study with a 4 L/min oxygen flow was performed. PH:7.41,pCO2:22.8mmHg,pO2:81mmHg,HCO3-:14.2, BE:-8.7mmol/L;WBC:14.46 × 109/L, N%:95.6%, Hb:98g/L; ALT: 43.5 u, AST: 88.74 u, LDH: 320 u, FIB: 7.33 g, D dimer: 8.49 mcg; Chest CT (Figs. 1a and d): Pneumonia in both lungs (patchy high-density opacities and large patchy consolidation with air space consolidation in the right upper lung and lower lung).Based on diagnostic criteria, the diagnosis is severe pneumonia, type I respiratory failure, and sepsis. After being admitted, the patient received meropenem for anti-infection and symptomatic support, but there was no appreciable improvement.1 days after admission, early in the morning, the patient was moved to the central ICU. When the blood mNGS test that afternoon revealed C psittaci, sequence 2, we promptly changed the patient's medicines to moxifloxacin and ceftriaxone and diagnosed her with psittacosis. The patient was intubated with a tracheal tube for assisted breathing (A/C mode, tidal volume 355ml, respiratory rate: 15 times/min, oxygen concentration: 35 L/min, F 20 times/min, tidal volume 400 mL, PEEP 12cmH₂O, FiO295%), and norepinephrine was administered to maintain blood pressure after the patient's oxygen saturation dropped to 75% during the night. The patient's amniotic burst 2 days after admission; the fetus was delivered intravaginally without the placenta, which was later extracted with forceps. The patient's bilirubin level rises and her platelets level falls over the course of the illness. Laboratory examination 6 days after admission: IBIL 140.2 umol/L, DBIL 326.4 umol/L, TBIL 466.6 umol/L, and Plt 57*10⁹ umol/L. Second chest CT (Figs. 1b and e): Both lungs have several foci of infection, both lungs have much more lesions than before, both lungs have lesions that are spreading more quickly than previously, and there is a little amount of pleural effusion on the right side. The anti-infective regimen was changed to azithromycin and meropenem, plasma exchange therapy, and blood purification therapy were all administered at the same time because the patient's bilirubin level was progressively rising. Moxifloxacin and medications that might harm the liver function were stopped. Vancomycin was administered to the blood 10 days after admission to treat the illness after a blood culture and identification revealed Enterococcus faecus(+).12 days after admission, the patient was awake and her temperature had returned to normal. The patient's symptoms progressively got better, and the patient was taken off the ventilator. The patient was then moved to the regular ward for rehabilitation exercises. Sixteen days after admission, the chest CT (Figs. 1c and f) revealed marked improvement of the lungs infiltrates.

Fig. 1.

Chest computed tomography at different time points after treatment. At admission (a,d), 5 days after admission (b,e), 16 days after admission (c,f).

Discussion

Psittacosis is a zoonotic illness, and studies have indicated that contact with birds is a key risk factor for developing the condition. C psittaci infection has been documented in 467 species of birds belonging to 30 bird groups [7]. The major mechanism of transmission of psittacosis is by inhalation of germs in bird droppings or respiratory secretions [1]. The occurrence of psittacosis is quite minimal; 60 instances were documented in the United States from 2008 to 2017 and 115 in Japan from 2007 to 2016 [8]. There have only been 3 cases of gestational psittacosis documented in China thus far, making it even more unusual. We found a case of prenatal psittacosis that delayed treatment and ultimately resulted in severe maternal pneumonia and fetal miscarriage because she was misdiagnosed.

Since goats, horses, and other animals are hosts for C psittaci as well [9], direct contact with infected birds and mammals can cause illness in humans. In a study of 23 previous cases of parrot fever during pregnancy, Daisuke Katsura et al. [10] discovered that 87% of patients had been exposed to sheep and goats before becoming ill. For this reason, it's crucial to focus not only on a history of bird exposure but also on a history of mammals exposure when treating psittacosis during pregnancy. The literature also examined the average age of patients with gestational psittacosis, which was determined to be 29 years (with a range of 20-36 years). This analysis demonstrated that while psittacosis infections are unlikely to affect young or older pregnant women, they can happen at any point in the pregnancy [10]. The patient in this case, who contracted C psittaci after coming into contact with pigeons a week ago, is 41 years old and is considered to be in her advanced maternal years, which shows that pregnant women of any age are vulnerable to C psittaci.

The incubation time follows human exposure to C psittaci is typically 5-14 days [5]. The most prevalent symptoms are a high temperature, headache, shortness of breath, cough, and exhaustion [11], [12], [13], [14]. It causes a range of clinical manifestations that accumulate in the lungs, liver, kidneys, heart, central nervous system, and hematologic systems [1]. Psittacosis patients can present clinically in a variety of ways, such as subclinical illness or flu-like symptoms (mild parrot fever), pneumonia (moderate parrot fever), severe pneumonia (severe parrot fever), or severe pneumonia coupled with multiple organ dysfunction syndrome (fulminant parrot fever) [15]. These clinical signs are similar with recent reports of prenatal psittacosis as well as our case, with 1 patient developing hemophilic syndrome, which ultimately led to maternal and fetal mortality [16], [17]. As the illness advanced, the patient's shortness of breath, cough, serious pneumonia, and multiorgan failure appeared. The case started with heat.

According to certain research, psittacosis patients had normal white blood cell counts and high neutrophil percentages, as well as possible abnormalities in the liver and kidneys, electrolyte changes, elevated CRP, and decreased ALT [11], [12], [18]. Our patient presented to us with an increased white blood cell count, which might have been caused by different bacterial illnesses. Thrombocytopenia, increasing rise in liver function bilirubin, other laboratory tests are hypoproteinemia, PCT, CRP increase, hypokalemia, hypernatremia, D dimer increase, muscle enzyme increase, and other abnormalities with illness development, consistent with prior investigations. Numerous investigations on psittacosis neglect to highlight alterations in platelets, making the patient's gradual platelet loss in this instance a notable signal. According to a recent study, platelets are a crucial factor in determining resistance and intravascular immunity; as a result, a reduction in platelets may signal an aggravation of psittacosis [19]. Psittacosis has a wide range of lung imaging characteristics, with consolidation, patchy, or ground-glass alterations being the most prevalent, along with a few instances of pleural involvement and pleural effusion on the afflicted side, according to earlier research [20], [21]. As the disease progressed, chest imaging in this patient revealed bilateral pneumonia with airbronchograms, patchy opacities, consolidation, and pleural effusion, which is similar with the majority of previously documented psittacosis cases.

The diagnosis of psittacosis has been a hot topic for a long time. The traditional methods for identifying C psittaci include microimmunofluorescence, complement fixation test, molecular detection (such as PCR), and microbial culture [5], which are less useful in clinical practice. Since the advent of mNGS in recent years, it has been possible to quickly and accurately detect a variety of uncommon clinical infections, offering a novel method for intractable infectious disorders [22]. Bronchoalveolar Fluid (BALF) has a greater diagnostic sensitivity than blood specimens in specimen selection for mNGS, according to a research by Duan et al. [8]. This may be because alveolar lavage fluid has a larger load of pathogen DNA than blood does [23]. Hu Li et al. discovered that psittacosis was detected using BALF, blood, and sputum samples, with the greatest sequence number in BALF, the second-highest sequence number in sputum, and the lowest sequence number in blood samples [24]. Sputum samples, followed by blood, are recommended for diagnosis by mNGS in patients who cannot undergo bronchoscopy since the blood specimen used in this case had a sequence number of just 2. We made the diagnosis within 48 hours of the mNGS test and promptly administered appropriate antibiotics, which served as a key guide for further therapy.

Tetracyclines, quinolones, and macrolides are the major medications utilized to treat psittacosis at the moment [25], since these antibiotics can obstruct DNA and protein synthesis. Macrolides are seen to be the best medication for pregnant women and young children with psittacosis, whereas tetracyclines are thought to be the first-line therapy for psittacosis [26], [27]. These 3 medications were not chosen in this instance because psittacosis had not been identified, and moxifloxacin was not begun until the patient experienced severe pneumonia and multiple organ failure. The failure to promptly deliver specific antibiotics ultimately resulted in the death of the fetus. According to 1 investigation, fetal and maternal fatality rates from psittacosis in pregnancy were 94% and 6.3%, respectively [28], although Daisuke Katsura et al. [10] found fetal and maternal mortality rates of 82.6% and 8.7%, respectively. According to this investigation, the inability to detect C psittaci infection in time for disease development is the leading cause of maternal and fetal death.

Conclusion

Psittacosis is an uncommon zoonotic illness, and gestational psittacosis is even rarer. Psittacosis can be easily misdiagnosed and missed. In clinical practice, if a pregnant patient is encountered with fever and respiratory symptoms who has recently been in touch with animals such as birds, sheep, and goats, mNGS testing should be performed as soon as possible and administer macrolide anti-infection medication.

Patient consent

Written informed consent for the publication of this case re-port was obtained from the patient.