LVEF: left ventricular ejection fraction, RVFAC: right ventricular
fractional area change
Follow ups: one patient underwent surgical removal of the thrombus which
was mobile and adherent to the tendon of tricuspid valve anterior
papillary muscle. Pathologically it showed patchy hemorrhagic necrosis
without a normal tissue structure. The thrombus in all the remaining
cases resolved with medical treatment in 22-89 days, median 53 days.
Discussion: Pediatric MP infection is usually mild and self-limiting.
However, it may cause serious complications in some children in addition
to the respiratory symptoms. There are growing reports of venous
thrombosis or arterial embolism as the result of a MP infection[7-10]. MP infection can lead to hypercoagulable
state, vascular endothelial damage, and even compromise the hepatic
function affecting the synthesis of coagulation factors and thrombin.
These multifactorial abnormalities can cause lower extremity venous
thrombosis, pulmonary and cerebral embolism, etc. MP intracardiac
thrombosis is rarely reported [6, 11].
Intracardiac thrombosis can be dangerous, as its detachment can cause
major organ embolism or infarction, with serious consequences including
disability and death [12-14]. Echocardiogram
confirming or further suspecting an intracardiac thrombus will lead to
further assessment and better treatment.
We found a case report of intraventricular thrombus associated with
mycoplasma pneumonia [11]. The patient was a
9-year-old boy. On the 10th day of symptom onset, an MRI found a space
occupying in the right ventricle which was surgically removed.
Pathological findings were new fibrin thrombus with scarce white blood
cells. The thrombus location, its illustrated and described characters,
were similar to those of our current cases. In our 4 cases, intracardiac
space occupying lesions were first revealed by echocardiography. The
characteristic of the space occupying lesion together with the diagnosis
of mycoplasma pneumonia and significantly elevated D-dimer lead to the
diagnosis or high suspicion of a thrombus. Although incidence of
mycoplasma pneumonia complicated with intracardiac thrombosis is very
low, nevertheless, such a thrombus is dangerous for potential pulmonary
embolism. Therefore, it is particularly important to have an
echocardiogram examination in patients with mycoplasma pneumonia and
significantly increased coagulation laboratory results. In our study,
the thrombus occurred between 9-11 days after the onset of the fever.
For those had higher D-dimer, we suggest an echocardiogram study 1-2
weeks after the onset of febrile illness to confirm or rule out a
thrombosis. Except 1 case with thrombectomy, the thrombus in all the
remaining cases is dissolved with medical treatment. Our cases suggest a
good prognosis with early detection of the thrombus and prompt
treatment. Otherwise, the large thrombus is a great risk for pulmonary
embolism. In conclusion, MPP complicated with ventricular thrombosis is
very rare. Therefore, when patients with MPP have abnormal coagulation
lab results, imaging study should be done to rule out or confirm the
thrombosis. Echocardiography plays an important role in the diagnosis
with its location, size, number, shape, activity and its relationship
with the surrounding tissues of the space occupying lesions. It also
offers repeated follow ups.
Reference
[1] F M Sánchez-Vargas, O G Gómez-Duarte. Mycoplasma pneumoniae-an
emerging extra-pulmonary pathogen. Clin Microbiol
Infect.2008;14(2):105-117
[2] Gu Haiyan, Zhao moral education, Wang Quan. 6 cases of
Mycoplasma pneumoniae pneumonia complicated with embolism. Chinese
Journal of Practical Pediatrics. 2016; 031(004):288-291 [3] C
Flateau, I Asfalou, A-L Deman, et al. Aortic thrombus and multiple
embolisms during a Mycoplasma pneumoniae infection. Infection.
2013;41(4):867-873
[4] Yu Chen, Ping Huang, Qi Che, et al. Two separated thrombi in
deep veins associated with pulmonary embolism after Mycoplasma
pneumoniae infection: a case in adolescent female. Transl Pediatr.
2013;2(4):198-201
[5] Mitsugi Nagashima, Takashi Higaki, Harumitsu Satoh, et al.
Cardiac thrombus associated with Mycoplasma pneumoniae infection.
Interact Cardiovasc Thorac Surg.2010;11(6):849-51.
[6] Li Qi Rui, Yuan Yue, Lin Li, et al. Two cases of Mycoplasma
pneumoniae pneumonia complicated with intracardiac thrombosis. Chinese
Journal of Pediatrics. 2018;56(12):950-951.
[7] A Pachet, C Dumestre-Perard, M Moine, et al. Splenic infarction
associated with transient anti-prothrombin antibodies is a rare
manifestation of acute Mycoplasma pneumoniae infection. Arch Pediatr.
2019;26(8):483-486
[8] Kwok Wang Chun, Yan See Wan, Wong Poon Chuen. Transient presence
of lupus anticoagulant associated with mycoplasma pneumonia. Asian
Cardiovasc Thorac Ann.2016;24(3):286-287
[9] Yunguang Bao, Xiaobing Li, Kaixuan Wang, et al. Central retinal
artery occlusion and cerebral infarction associated with Mycoplasma
pneumonia infection in children.BMC Pediatr.2016;16(1):210.
[10] Sarathchandran P , Madani A A , Alboudi A M , et al. Mycoplasma
pneumoniae infection presenting as stroke and meningoencephalitis with
aortic and subclavian aneurysms without pulmonary involvement. Bmj Case
Rep.2018,2018:bcr-2017-221831.
[11] Mitsugi N, Takashi H, Harumitsu S, et al. Cardiac thrombus
associated with Mycoplasma pneumoniae infection[J]. Interactive
Cardiovascular and Thoracic Surgery. 2010;(11):849–851.
[12] Graw-Panzer KD, Verma S, Rao S, et al. Venous thrombosis and
pulmonary embolism in a child with pneumonia due to Mycoplasma
pneumoniae. J Natl Med Assoc. 2009; (101):956–958.
[13] Kang B, Kim DH, Hong YJ, et al. Complete occlusion of the right
middle cerebral artery associated with Mycoplasma pneumoniae pneumonia.
Kor J Pediatr. 2016; (59):149–152.
[14] Ferro JM, Massaro AR, Mas JL. Aetiological diagnosis of
ischaemic stroke in young adults. Lancet Neurol. 2010;(9):1085–1096.