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Year : 2021  |  Volume : 8  |  Issue : 4  |  Page : 197-199

Left atrial thrombus: Rare and unusual presentation of Mycoplasma pneumoniae infection: A case Report

DivisionofPediatricCriticalCare,DepartmentofPedaitrics,SahyadriSuperspecialityHospital,Shashtrinagar,Pune,Maharashtra, India

Date of Submission26-Feb-2021
Date of Decision25-Mar-2021
Date of Acceptance08-Apr-2021
Date of Web Publication10-Jul-2021

Correspondence Address:
Dr. Sagar Lad
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpcc.jpcc_17_21

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Mycoplasma pneumoniae is a common organism responsible for pediatric community-acquired pneumonia. Extrapulmonary complications including thrombosis, although rare, are known to be associated with severe M. pneumoniae pneumonia. We report the case of left atrial thrombus extending into right inferior pulmonary vein in a child with severe M. pneumoniae probably due to transient Antiphospholipid Antibodies (aPL). Pneumonia and thrombus were completely resolved after the treatment with antimicrobial and anticoagulant therapy in 3 months. aPL are more common in M. pneumoniae infections; hence, routine screening will be helpful to quantify the incidence of aPL as well as to plan future risk assessment and management strategies.

Keywords: Antiphospholipid antibodies, left atrium, Mycoplasma pneumoniae pneumonia, thrombosis

How to cite this article:
Lad S, Suryawanshi P, Kait S, Lad P, Mujawar J. Left atrial thrombus: Rare and unusual presentation of Mycoplasma pneumoniae infection: A case Report. J Pediatr Crit Care 2021;8:197-9

How to cite this URL:
Lad S, Suryawanshi P, Kait S, Lad P, Mujawar J. Left atrial thrombus: Rare and unusual presentation of Mycoplasma pneumoniae infection: A case Report. J Pediatr Crit Care [serial online] 2021 [cited 2021 Sep 19];8:197-9. Available from: http://www.jpcc.org.in/text.asp?2021/8/4/197/321097

  Introduction Top

In school-going children, approximately 10%–40% of community-acquired pneumonia cases are due to Mycoplasma pneumonia.[1] Most of these cases are mild to moderate and confined to the lungs only but some may become severe with life-threatening complications. Arthritis, hepatitis, pericarditis, hemolytic anemia, central nervous system sequelae, and thrombosis are various extrapulmonary complications.[2] Thrombus in the cerebral arteries is common, but thrombus in the left atrium extending to the pulmonary vein is very rare. We report the case of left atrial thrombus; a rare complication of M. pneumoniae infection wherein thrombosis was related to transient antiphospholipid antibodies (aPL) which was completely resolved with therapy.

  Case Report Top

A 4-year-old girl was admitted in the pre-COVID period in December 2019 with a history of fever and cough for 15 days with one seizure episode with no significant past history. She also had right knee pain and was not able to walk. Parents also noticed right leg was cold with change in skin color. On admission, she was conscious and oriented with Glasgow Coma Scale 13. She was febrile and tachypneic with oxygen saturation 91% in room air, mild subcostal and intercostals retractions, decreased air entry on the right side and crepitations. Her right lower limb was pale, cold with Grade 2 power. Right popliteal artery and dorsalis pedis artery pulsations were feeble. Her other systemic examination was normal.

Her chest X-ray showed right middle and lower lobe consolidation with synpneumonic effusion. Right lower limb Doppler study showed thrombosis in the distal superficial femoral artery [Figure 1]. Two-dimensional (2 D) echocardiogram (ECHO) and later on cardiac magnetic resonance imaging (MRI) confirmed a well-defined 20 mm × 16 mm × 7 mm thrombus arising from the right inferior pulmonary vein with extension into the left atrium with base attached to interatrial septum. Hemogram showed hemoglobin 9.2 g/dL, total leukocytic count 7500 per cu.mm (N70% L21%), platelets count 2,80,000 per cu.mm, and C-reactive protein (CRP) 49 mg/L. A cold agglutinin test and direct Coombs' test were positive. Prothrombin time, international normalized ratio, APTT Activated Partial Thromboplastin Time (PTTK), Protein C and S, antithrombin III and Factor V Leiden mutation, and lupus anticoagulant were normal. M. pneumoniae IgM antibody (enzyme-linked immunosorbent assay) was strongly positive (73.15U/ml). Anti-phospholipid IgG antibodies were positive (20.109 U/ml).
Figure 1: Two-dimensional echocardiogram showing thrombus in the left atrium (arrow)

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She was managed with oxygen therapy, antibiotics ceftriaxone, vancomycin, and low-molecular-weight heparin. Initially, oral azithromycin was given and then changed to oral doxycycline due to persistence of fever. Repeat 2D ECHO showed resolving thrombus in the left atrium. MRI of the brain with magnetic resonance angiography showed mild narrowing at origin of both divisions of the left middle cerebral artery but normal neuroparenchyma. After 15 days, lower limb Doppler was normal. She recovered well and was able to walk properly and was discharged on oral doxycycline for total 10 days and subcutaneous Low Molecular weight Heparin (LMVH) for 3 weeks. Repeat 2D ECHO at 3 months' follow-up was normal, and antiphospholipid antibodies were negative.

  Discussion Top

Here, we describe a 4-year-old girl with severe M. pneumoniae pneumonia with thrombus in the left atrium arising from right inferior pulmonary vein, thrombosis in the distal superficial femoral artery, and mild narrowing at the origin of left middle cerebral artery. On evaluation, we found positive IgG antiphospholipid antibodies which turned normal after 3 months. Laboratory evaluation on follow-up suggested that her prothrombotic state was due to the transient antiphospholipid antibodies induced by the M. pneumoniae infection. Liu et al. reported five such cases of pulmonary vein thrombosis (in one case, there was the involvement of the left atrium).[3]

Thrombosis in children is uncommon, and the presence of a central venous catheter is the most common precipitating factor.[4] Severe Mycoplasma pneumoniae as in our case is the most strongly associated risk factor for thrombosis. The severity of airway damage such as necrosis and airway remodeling correlates well with severity of lobar consolidation and with the levels of inflammatory markers such as CRP and lactate dehydrogenase.[5] The “molecular mimicry” and immunomodulations may be responsible for the generation of anti-phospholipid antibodies in Mycoplasma pneumoniae infections. Antiphospholipid antibodies inhibit the fibrinolytic system and initiate the extrinsic pathway of coagulation. Antiphospholipid antibodies also cause a hypercoagulable state by promoting the cellular activation of platelets as well as the complement system.[6] Very few cases of thrombus in the left atrium have been reported in children with M. pneumoniae infections associated with transient antiphospholipid antibodies.[3],[7] These reported patients including ours did not have any congenital pro-thrombotic condition. The outcome of thrombotic events in M. pneumoniae pneumonia is usually favorable with antimicrobial treatment and anticoagulation therapy.[8] Similar cases have been reported in Indian children by Mekala et al.[9]

Mycoplasma infections have the high possibility of triggering autoimmune responses such as a cold agglutinin response in 70% and developing thrombosis. Antiphospholipid antibodies (aPL) are more common in mycoplasma infections; hence, routine screening of these antibodies should be advised. This will be helpful to quantify the incidence of aPL as well as to plan future risk and management strategies.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Jain S, Williams DJ, Arnold SR, Ampofo K, Bramley AM, Reed C, et al. Community-acquired pneumonia requiring hospitalization among U.S. children. N Engl J Med 2015;372:835-45.  Back to cited text no. 1
Ovetchkine P, Brugie'res P, Seradj A, Reinert P, Cohen R. An 8-year-old boy with acute stroke and radiological signs of cerebral vasculitis after recent Mycoplasma pneumoniae infection. Scand J Infect Dis 2002;34:307-9.  Back to cited text no. 2
Liu J, He R, Wu R, Wang B, Xu H, Zhang Y, et al. Mycoplasma pneumoniae pneumonia associated thrombosis at Beijing Children's hospital. BMC Infect Dis 2020;20:51.  Back to cited text no. 3
Monagle P, Cuello CA, Augustine C, Bonduel M, Brandão LR, Capman T, et al. American Society of Hematology 2018 Guidelines for management of venous thromboembolism: Treatment of pediatric venous thromboembolism. Blood Adv 2018;2:3292-316.  Back to cited text no. 4
Liu JR, Lu J, Dong F, Li HM, Liu H, Tang XL, et al. Low bacterial co-infection invalidates the early use of non-anti-Mycoplasma pneumoniae antibiotics in pediatric refractory Mycoplasma pneumoniae pneumonia patients. Front Pediatr 2018;6:296.  Back to cited text no. 5
Comarmond C, Cacoub P. Antiphospholipid syndrome: From pathogenesis to novel immunomodulatory therapies. Autoimmun Rev 2013;12:752-7.  Back to cited text no. 6
Bakshi M, Khemani C, Vishwanathan V, Anand RK, Khubchandani RP. Mycoplasma pneumonia with antiphospholipid antibodies and a cardiac thrombus. Lupus 2006;15:105-6.  Back to cited text no. 7
Flateau C, Asfalou I, Deman AL, Ficko C, Andriamanantena D, Fontan E, et al. Aortic thrombus and multiple embolisms during a Mycoplasma pneumoniae infection. Infection 2013;41:867-73.  Back to cited text no. 8
Mekala S, Delhi Kumar CG, Gulati R. Antiphospholipid syndrome complicating pneumococcal meningitis. Indian Pediatr 2018;55:429-31.  Back to cited text no. 9


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