Mycoplasma pneumoniae pneumonia associated thrombosis at Beijing Children's hospital

Abstract

Background: With the increase of awareness of mycoplasma pneumoniae pneumonia (MPP), we found thrombosis in severe MPP (SMPP) was not rare. The aim of the study was to investigate the clinical characteristics, treatment, and long-term prognosis of MPP-associated thrombosis.

Methods: We retrospectively reviewed the medical records of 43 children with MPP-associated thrombosis between January 2013 and June 2019 at Beijing Children's Hospital. The results of blood coagulation studies, autoimmune antibody, thrombophilia screening, contrast-enhanced lung computed tomography, echocardiography, and blood vessel ultrasonography were analyzed, as were treatment outcomes.

Results: Forty-two patients were diagnosed with SMPP. D-dimer was higher than 5.0 mg/L in 58.1% (25/43) of patients. The mean D-dimer level was 11.1 ± 12.4 mg/L. Anticardiolipin-IgM was positive in 60.0% of patients, β2-glycoprotein-IgM in 64.0%, and lupus anticoagulant in 42.1%. Chest imaging revealed pulmonary consolidation with lobe distribution in all patients (2/3-1 lobe in 10 patients, > 1 lobe in 29 patients). In our experience, thrombosis can occur in a vessel of any part of the body, and it can be initially detected as late as 31 days after disease onset. Thrombosis in the brain and abdomen can occur early, at 5 days after disease onset. Pulmonary vessels were the most commonly involved sites in the current study, and accordingly chest pain was the most common symptom (32.6%), followed by neurological symptoms (14.0%) and abdominal pain (9.3%). Thirty-five percent of patients were asymptomatic with regard to thrombosis. All patients underwent anticoagulant therapy, and thrombus absorption took > 3 months in most patients. All patients were followed until October 2019, at which time 41 were asymptomatic and 2 had mild recurrent cough.

Conclusions: SMPP with pulmonary consolidation (> 2/3 lobe) was the most strongly associated risk factor for thrombosis. Thrombosis-associated symptoms may be subtle, even absent. Elevated D-dimer, specifically > 11.1 mg/L (even > 5.0 mg/L), would assist in the early diagnosis of thrombosis. The long-term prognosis of thrombosis was good after timely administration of anticoagulant therapy.

Keywords: Children; Mycoplasma pneumoniae; Pneumonia; Severe; Thrombosis.

Fig. 1

The annual case number of MPP-associated thrombosis between January 2013 and June 2019

Fig. 2

Chest imaging revealed consolidation with high density in the right upper lung (a). 3D-TOF MRA image of the brain didn’t reveal the A1 segment of the right anterior cerebral artery (b), and the T2 FLAIR transverse image showed a patchy high signal in the right parietal cerebral palsy and the right basal ganglia (c, d). Abdominal enhanced CT and 3D vascular reconstruction revealed the superior mesenteric artery thrombosis (e, f, g), and multiple small infarction in the spleen (e, h)

Fig. 3

Lung enhanced CT and 3D vascular reconstruction revealed right lower pulmonary artery thrombosis (a, b), necrosis within consolidation of the left lower lung (b), low-density necrosis of the right lower lung with cavity formation, and the strip filling defect in the right lower pulmonary vein extended to the left atrium (c), necrosis of the right lower lung (d) with right lower pulmonary vein occlusion (d, e), and right pulmonary artery thrombosis (f)