COVID-19 Coinfection with Mycoplasma Pneumoniae

A 50-year-old male with recent positive coronavirus disease-19 RT-PCR and obesity (BMI 31.7) presented with dyspnea, myalgias, nausea and persistent dry cough. Laboratory studies were remarkable for lymphopenia (0.6×10³/µL), elevated c-reactive protein, ferritin, procalcitonin, interleukin-6, and d-dimer. A respiratory antigen panel was obtained and was positive for Mycoplasma IgM antibodies.

AP chest x-ray on admission demonstrated multifocal bilateral, peripheral-predominant patchy solid and ground-glass opacities, compatible with atypical viral pneumonia (Fig. 1).

Non-contrast CT chest on admission demonstrated multifocal bilateral, peripheral-predominant patchy ground-glass and consolidative opacities. Mild traction bronchiectasis was noted. There were subpleural and intraparenchymal cystic changes incidentally noted in the bilateral lower lobes and lingula. Scattered mildly prominent mediastinal lymph nodes, including one 1.1 cm right paratracheal lymph node, were noted (Figs. 2a-e).

AP chest x-ray on day two of admission demonstrated increased bilateral patchy peripheral-predominant, likely associated with a multifocal infectious process such as viral pneumonia. Bilateral low lung volumes were noted (Fig. 3).

Background

Coronavirus disease-19 (COVID-19), a novel viral pandemic, has rapidly increased in incidence and can present with a wide range of symptoms and disease severity [1]. Morbidity and mortality have been shown to be associated with multiple comorbidities, including obesity [2].

Clinical Perspective

There is limited literature on patients with COVID-19 who are coinfected with other respiratory pathogens, including mycoplasma pneumonia [3]. Chest computed tomography (CT) and serial chest x-rays can aid in the diagnosis and monitoring of COVID-19 progression. Imaging characteristics for COVID-19 tend to follow a common trend, with an early stage, progressive stage, peak stage, and absorption stage. The greatest severity is seen around ten days after the initial onset of symptoms [4].

Imaging Perspective

On chest CT, bilateral peripheral ground-glass opacities with absence of lymphadenopathy, pleural effusions, pulmonary nodules, and lung cavitations are characteristic findings in patients with COVID-19 [5-7]. Of note, significant overlap exists between imaging characteristics of COVID-19 and other respiratory pathogens. Furthermore, it is still relatively unclear how coinfection with mycoplasma pneumoniae or other respiratory pathogens may affect imaging [8]. However, the presence of lymphadenopathy, pleural effusion, or pulmonary nodules may suggest the presence of bacterial coinfection [9]. Common findings in patients with mycoplasma pneumoniae infection include bronchial wall thickening, centrilobular nodules, ground-glass attenuation, and air-space consolidation on chest CT [10,11].

Outcome

On day two of admission, the patient was transferred to the ICU for worsening hypoxic respiratory failure and increased oxygen requirement. He was found to have positive IgM antibodies for mycoplasma and was started on doxycycline for possible coinfection. His symptoms gradually improved, and oxygen was weaned. He did not require intubation or ventilatory support.

Take-Home Message / Teaching Points

COVID-19 has several imaging findings that are dependent upon the time course of symptoms. Many imaging findings overlap between COVID-19 and other respiratory infections. Mediastinal lymphadenopathy may be suggestive of bacterial coinfection. Radiologists and clinicians must consider the possibility of respiratory coinfection when treating patients with COVID-19.