A cоmplete blооd count аnd serum biochemicаl profile аre performed on a three year old Labrador Retriever with a chronic fever of unknown origin.Which of the following test results is unexpected, and may therefore be a valuable diagnostic clue?
Initiаl pоst оn Pulmоnаry Embolisms (PE) Pulmonаry Embolisms Pulmonary embolisms (PE) are potentially fatal blood clots in the pulmonary artery that block the passage of blood flow to the lungs. Pulmonary embolisms often go undiagnosed due to the acute onset and vague symptoms it presents with. PE is a potential cause of death that is often seen in clinical settings with most being discovered by autopsy. Myocardial infarction and stroke precede pulmonary embolisms as the top three most frequent acute cardiovascular syndromes. If caught early, this potentially fatal blockage can be treated with medications and surgery that greatly increase the chance of survival. Etiology Embolism refers to a thrombus that breaks off and travels to another place in the body. So a pulmonary embolism is caused by a thrombus that has broken away and traveled to the pulmonary artery. Pulmonary embolisms are often caused by deep vein thrombosis that originate in the leg or hip area.”Most PEs originate from the deep veins of lower extremity. The common sites of thrombus formation are in the calf veins followed by femoropopliteal veins and finally the iliac veins. A blood clot dislodges from the vessel wall and travels into the pulmonary system, eventually lodging in the pulmonary arteries.” (Shah 2022).The thrombus can then travel from its origin, then to the inferior vena cava, then to the right side of the heart, and then to the pulmonary artery causing a blockage of pulmonary circulation. When the thrombus travels to the pulmonary artery, it is then classified as a pulmonary embolism. Pulmonary embolisms can also originate in the right side of the heart called an atrial thrombus. They then move from the right side and are pumped into the pulmonary artery. Central venous catheters are also a common origin of thrombosis that can break off and travel to the pulmonary artery. Genetic Factors There does not appear to be much of a connection between genetics and pulmonary embolisms. PE are caused by deep vein thrombosis, so if someone has a disposition for blood clots, they are at an increased risk for PE. Some factors that can increase the risk for thrombosis are obesity, sedentary lifestyle, bedrest, and immobility. Obesity puts women at a greater risk for pulmonary embolisms than obese men. “ In the multivariable Cox regression models, the anthropometric obesity markers of weight, body mass index, waist and hip circumference, fat percentage, and muscle weight were in a dose‐dependent way associated with DVT and PE among women but not men.” (Brink 2023). Trauma and invasive surgeries also increase risk for PE. Assessment and Clinical Manifestations The signs and symptoms of pulmonary embolisms can be extremely vague, which makes it very difficult to diagnose. The patient is experiencing difficulty breathing due to the decrease in pulmonary circulation and pulmonary tissue perfusion. Due to this difficulty breathing, patients may present with pale color, labored breathing, clutching their chest etc. Common symptoms of PE also include cough, dyspnea, and chest pain. Most PE are not diagnosed until an autopsy is performed because the symptoms are vague and have an acute onset. “ However, the actual incidence rates are likely significantly higher, as many patients are asymptomatic and many others are underdiagnosed or misdiagnosed. For instance, there are reports of silent PE in 40–50% of patients with proximal DVT and numerous PEs incidentally found upon autopsy” (Thomas 2024). Diagnosis Pulmonary embolisms are typically diagnosed using either a D-dimer test or CT pulmonary angiography test. The D-dimer test is a diagnostic test that measures fibrin particles in the blood. If the test is in a normal range, it is indicative that there is unlikely a pulmonary embolism. The more common test is the CT pulmonary angiography. The angiography is performed by placing a catheter in the large vein in the upper leg that is then used to insert contrast dye into the vein. This dye allows easy view of the blood vessels and blood flow in the lungs to detect blockages when viewed via CT scan. Pathophysiology Pulmonary embolisms are thrombi that commonly originate in the lower extremity and travel through the vena cava to the pulmonary artery. This thrombus will then become lodged in the pulmonary artery and prevent the passage of blood flow from the heart, through the pulmonary artery, and to the lungs. The loss of pulmonary circulation causes the perfusion of the lung tissue to diminish which can lead to death. A PE can lead to acute right ventricular heart failure. The PE raises pressure in the right ventricle which causes the right ventricle to become weak and can eventually lead to this acute failure. Treatment Treatment for PE includes using direct oral anticoagulants (DOAC). Examples of DOAC include medications like Rivaroxaban and Apixaban to treat the thrombus. DOAC drugs are preferred over vitamin K antagonist Warfarin because Warfarin can cause an excess risk of bleeding compared to the DOAC drugs. Anticoagulants should be used for at least three months to prevent the PE from returning. Thrombolytic agents can be used to treat PE if there is hemodynamic instability. Surgery for PE may be needed if there are multiple clots. During surgery, a filter would be implanted in the inferior vena cava to filter out the clots. Conclusion In conclusion, Pulmonary embolisms are life threatening blood clots that travel to become lodged in the pulmonary artery and prevent blood flow to the heart. PEs are difficult to diagnose because of their sudden onset and vague symptoms. If caught early, PEs are treatable by way of medications and surgery. References Brink, A., Elf, J., Svensson, P., Gunnar Engström, Melander, O., & Bengt Zöller. (2023). Sex‐Specific Risk Factors for Deep Venous Thrombosis and Pulmonary Embolism in a Population‐Based Historical Cohort Study of Middle‐Aged and Older Individuals. Journal of the American Heart Association, 12(5). https://doi.org/10.1161/jaha.122.027502 Shah, I. K., Merfeld, J. M., Chun, J., & Tak, T. (2022). Pathophysiology and management of pulmonary embolism. International Journal of Angiology, 31(03), 143–149. https://doi.org/10.1055/s-0042-1756204 Thomas, S. E., Weinberg, I., Schainfeld, R. M., Rosenfield, K., & Parmar, G. M. (2024). Diagnosis of Pulmonary Embolism: A Review of Evidence-Based Approaches. Journal of Clinical Medicine, 13(13), 3722. https://doi.org/10.3390/jcm13133722
Which perspective emphаsizes thоught prоcesses, beliefs, аnd infоrmаtion processing?