# The Delayed Diagnosis of a Submassive Pulmonary Embolism Following Influenza A Infection Treated With Half-Dose Tenecteplase: A Case Report

## TL;DR

A 62-year-old woman with influenza A developed a submassive pulmonary embolism, which was successfully treated with half-dose tenecteplase after a delayed diagnosis.

## Contribution

This case report highlights the use of half-dose tenecteplase for submassive PE following influenza A, emphasizing its potential as a treatment option.

## Key findings

- The patient showed significant clinical improvement after receiving half-dose tenecteplase.
- Follow-up imaging revealed a notable reduction in thrombus burden.
- Half-dose thrombolytics may offer a safer alternative for submassive PE treatment.

## Abstract

The coronavirus 2019 (COVID-19) pandemic has brought renewed attention to thrombotic complications arising from respiratory viral infections, driven by inflammatory responses and activation of the coagulation cascade. While influenza typically resolves on its own, information about its thromboembolic risks remains limited. The persistence of symptoms and the similarity between influenza symptoms and those of pulmonary embolism (PE) often lead to diagnostic delays, which can significantly impact patient outcomes. We discuss a case of a 62-year-old woman with a history of hypertension and hyperlipidemia who presented with dyspnea, syncope, and persistent symptoms following influenza A infection. Despite initial treatment with Tamiflu and subsequent antibiotics for presumed pneumonia, her condition worsened, leading to syncope and admission to the hospital. A diagnostic workup revealed saddle pulmonary emboli with right ventricular strain. She was treated with a half-dose of tenecteplase, resulting in significant clinical improvement and a notable reduction in thrombus burden on follow-up imaging.

The thromboembolic complications of influenza A are not extensively documented compared to COVID-19, yet they can present with severe outcomes. Submassive PE, characterized by hemodynamic stability with signs of right ventricular strain, poses treatment challenges. While full-dose thrombolytics are generally avoided in intermediate-risk PE due to bleeding risks, half-dose thrombolytics such as tenecteplase can offer a safer alternative. Though not FDA-approved specifically for PE, tenecteplase has shown efficacy and was effectively used in this case. Half-dose thrombolytics, including tenecteplase, may be a viable treatment option for certain cases of PE, offering a balance between efficacy and safety. This case highlights the importance of considering PE in patients with persistent respiratory symptoms post-influenza and demonstrates the potential of tenecteplase in managing submassive PE.