Pulmonary Embolism: novel corona virus versus tuberculosis

This series describes six paediatric cases who presented as severe acute respiratory illness during the pandemic of covid-19 with high D-dimer levels. All six patients tested negative for novel corona virus. They were diagnosed as having tuberculosis on detailed investigations; High D-dimer levels are one of the most important indicators of the pulmonary embolism. Pulmonary embolism is a rare presentation of tuberculosis and this study emphasizes the need of keeping tuberculosis as an important differential diagnosis of those who present as acute respiratory distress syndrome. a case series of six tuberculosis presenting with pulmonary embolism having no risk factor for hypercoagulability.(2) et 3 cases of pulmonary embolism associated with severe pulmonaryTB(3). Turken O and others the hemostatic changes along with inammation leading to hypercoaguable state in severe pulmonaryTB which improves with treatment. They compared various hematological parameters in severe PTB versus that of control (4). Although not common, tuberculosis especially severe pulmonary/ disseminated is at risk for venous thrombosis (5). Goncalves, Ivone M et al presented two case reports where two adult patients had thromboembolic events following severe pulmonaryTB(6).One recent study recommended use of prophylactic LMWH(low molecular weight heparin) in patients with covid -19 pneumonia presented with high d-dimer levels on admission or sudden clinical worsening which was attributed to pulmonary embolism(7). They also recommended CTPA pulmonary angiography) in place of non-contrast CT when possible to document pulmonary embolism(7). A study related appearance progression revealed predominant peripheral location, common progression pattern from unilateral focal to unilateral multifocal/bilateral involvement during treatment, and lack of cavitation, lymphadenopathy, and pleural effusion as the more distinctive radiographic ndings of SARS(8). Our cases presented with a picture like SARS initially to suspicion covid pneumonia which on HRCT thorax showed few ndings suggestive of basic etiology as tuberculosis.


Introduction
Tuberculosis(TB) is very prevalent in developing countries. PulmonaryTB usually presents with cough, fever and weight loss. Presentation as severe acute respiratory illness(SARI) due to pulmonary embolism is not usual\. On the other hand, ongoing recent illness-novel coronavirus (SARS Co-V2/ COVID-19) is known for its presentation as SARS(severe acute respiratory distress syndrome) and high d-dimer levels.
We are presenting a case series of six patients who presented as (SARI) with high D-dimer. All of them on detailed investigation were diagnosed as having pulmonaryTB.
We have included six patients who presented as SARI (table1). Age ranged between 11-17 years. Duration of fever was 3-4 days except in one (patient-3, table1) where it was on-off since six months. Onset of di culty in breathing was 1-2 days prior to admission. Five patients had no signi cant prior illness, whereas one had diabetes mellitus (patient-6, table1). Two patients (patient-2and 6, table1) had history of positive koch's contact. None was exposed to covid-19.
In view of current pandemic of covid-19, patients were rst suspected as having covid pneumonia and primary treatment was started (oxygen therapy, antibiotics, supportive) .
Four patients had chest X-ray suggestive of ARDS (acute respiratory distress syndrome)( gure 2A), one patient had predominant single lung involvement in form of diffuse peripheral opacities and the other patient(patient-3,table1) had chest x-ray suggestive of miliary tuberculosis( gure 2B). HRCT thorax of four patients was suggestive of tuberculosis in form of tree in bud appearance/consolidation/cavitatory lesions/mediastinal lymphnodes enlargement ( gure 3A and 3B). CTPA (CT pulmoanry angiography) was done in one patient(patient-6,table1) which was normal( gure 3D). All patients tested negative for novel corona virus Repeat samples for covid were sent in two patients also reported negative. Keeping in consideration other systemic ndings and supportive laboratory evidences in form of sputum CBNAAT, montoux test, ultrasound abdomen all were diagnosed as having pulmonary TB with one patient(patient-5,table1) also having abdominal tuberculosis(disseminated TB). Two patients who presented with severe respiratory distress required ventilatory care and could not survive in spite of our best efforts (patient 1and2, table1). One (patient-2, table1) of them had sudden deterioration in twelve hours in both clinical and radiological picture( gure 1). Out of rest four, three patients required high ow oxygen therapy for 3-4 days. LMWH (low molecular weight heparin) was given to patients with initial high d-dimer along with methylprednisolone to patients with severe ARDS. Subsequent reports showed decline in d-dimer levels along with clinical improvement. All four patients who survived were discharged on antiTB treatment.

Discussion
PulmonaryTB is very prevalent in developing countries. Estimated incidence of tuberculosis in India(2018) was 2.69million(199/100000 population)(1). One study in adults showed series of ve patients with different forms of tuberculosis presenting with pulmonary embolism having no risk factor for hypercoagulability.(2) Kwas H, et al reported 3 cases of pulmonary embolism associated with severe pulmonaryTB(3). Turken O and others describes the hemostatic changes along with in ammation leading to hypercoaguable state in severe pulmonaryTB which improves with treatment. They compared various hematological parameters in severe PTB versus that of control (4). Although not common, tuberculosis especially severe pulmonary/ disseminated is at risk for venous thrombosis (5). Goncalves, Ivone M et al presented two case reports where two adult patients had thromboembolic events following severe pulmonaryTB (6).One recent study recommended use of prophylactic LMWH(low molecular weight heparin) in patients with covid -19 pneumonia presented with high d-dimer levels on admission or sudden clinical worsening which was attributed to pulmonary embolism (7). They also recommended doing CTPA (CT pulmonary angiography) in place of non-contrast CT when possible to document pulmonary embolism (7). A study related to radiographic appearance and patterns of progression revealed predominant peripheral location, common progression pattern from unilateral focal air-space opacity to unilateral multifocal/bilateral involvement during treatment, and lack of cavitation, lymphadenopathy, and pleural effusion as the more distinctive radiographic ndings of SARS (8). Our cases presented with a picture like SARS initially leading to high suspicion of covid pneumonia which on HRCT thorax showed few ndings suggestive of basic etiology as tuberculosis.

Conclusion
Our case series shows that tuberculosis can present as pulmonary embolism in adolescents which presents clinically as SARI. This is the rst case series reporting pulmonary embolism as the presentation of tuberculosis in children. In the era where we are attributing novel corona virus as cause of majority SARS cases, it is necessary to investigate for underlying tubercular etiology for early initiation of treatment. Table   Table 1