On an erect chest X-ray, a hemothorax is suggested by blunting of the costophrenic angle or partial or complete opacification of the affected half of the thorax. On a supine film the blood tends to layer in the pleural space, but can be appreciated as a haziness of one half of the thorax relative to the other. A small hemothorax may be missed on a chest X-ray as several hundred milliliters of blood can be hidden by the diaphragm and abdominal viscera on an erect film. Supine X-rays are even less sensitive and as much as one liter of blood can be missed on a supine film. Other methods
Ultrasonography may be used to detect hemothorax and other pleural effusions. This technique is of particular use in the critical care and trauma settings as it provides rapid, reliable results at the bedside. Ultrasound is more sensitive than chest x-ray in detecting hemothorax. Ultrasound can cause issues in people who are morbidly obese or have subcutaneous emphysema. When CT is unavailable in the current setting or the person cannot be moved to the scan, ultrasound is used.Computed tomography (CT or CAT) scans may be useful for diagnosing retained hemothorax as this form of imaging can detect much smaller amounts of fluid than a plain chest X-ray.
This clot tends to stick the parietal and visceral pleura together and has the potential to lead to scarring within the pleura, which if extensive leads to the condition known as a fibrothorax. Following the initial loss of blood, a small hemothorax may irritate the pleura, causing additional fluid to seep out, leading to a bloodstained pleural effusion. Furthermore, as enzymes in the pleural fluid begin to break down the clot, the protein concentration of the pleural fluid increases. As a result, the osmotic pressure of the pleural cavity increases, causing fluid to leak into the pleural cavity from the surrounding tissues. Diagnosis
Hemothoraces are most commonly detected using a chest X-ray, although ultrasound is sometimes used in an emergency setting. It can be suspected in any person with any form of chest trauma. However, plain X-rays may miss smaller hemothoraces while other imaging modalities such as computed tomography (CT), or magnetic resonance imaging may be more sensitive. In cases where the nature of an effusion is in doubt, a sample of fluid can be aspirated and analysed in a procedure called thoracentesis. Physical examination is used initially. Auscultation has been reported to have an accuracy of nearly 100% in diagnosing hemopneumothorax. Chest X-ray
A chest X-ray is the most common technique used to diagnosis a hemothorax. X-rays should ideally be taken in an upright position (an erect chest X-ray), but may be performed with the person lying on their back (supine) if an erect chest X-ray is not feasible.