A Fatal Case of Cardiac Contusion After Blunt Chest Injury.

ABSTRACT: In this article, we report the autopsy findings of a 48-year-old man who sustained blunt trauma to the thorax. A medical record review revealed no history of cardiac disease. He presented to the hospital with a computed tomography-verified fracture of the left fourth and fifth ribs, and pulmonary and cardiac contusion. He was released from the hospital in stable condition at his own request 7 days later. Because of sudden deterioration, he was readmitted to the hospital the next day. Electrocardiogram detected cardiac arrhythmia on the 15th day after chest trauma. Electrocardiography detected pericardial effusion and severe mitral insufficiency resulting in left ventricular failure. Death was attributed to diffuse alveolar damage-complicating pneumonia due to cardiac contusion with mitral insufficiency occurring 25 days after hospital admission. Internal examination revealed diffuse fibrinous pericarditis, left atrial tear right above the anterior mitral valve leaflet with intrapericardial granulation tissue, and no sign of myocardial damage. Immunohistochemistry showed significantly more CD68-positive macrophages within tissue taken from the heart, a finding indicative of previous atrial and ventricular myocardial contusion. This case report demonstrates that routine hematoxylin and eosin staining may not always reveal significant myocardial damage.

Management of Seat Belt-type Blunt Abdominal Aortic Trauma and Associated Injuries in Pediatric Patients.

BACKGROUND: "Seat belt-type" pediatric abdominal aortic trauma is uncommon but potentially lethal. During high speed motor vehicle collisions (MVCs), seat or lap belt restraints may concentrate forces in a band-like pattern across the abdomen, resulting in the triad of hollow viscus perforation, spine fracture, and aortoiliac injury. We report 4 cases of pediatric seat belt-type aortic trauma and review management strategies for the aortic disruption and the associated constellation of injuries. METHODS: -approved, retrospective review of all pediatric patients requiring surgical intervention for seat belt-type constellation of abdominal aortic/iliac and associated injuries over a 5-year period. Blunt thoracic aortic injuries were excluded. RESULTS: We identified 4 patients, ranging from 2 to 17 years of age, who required surgical correction of seat belt-type aortoiliac trauma and associated injuries: 3 abdominal aortas and 1 left common iliac artery. The majority (3/4 patients) were hemodynamically unstable at emergency room presentation, and all underwent computed tomography angiography of the chest/abdomen/pelvis during initial resuscitation. Injuries of the suprarenal and proximal infrarenal aorta were accompanied by unilateral renal artery avulsion requiring nephrectomy. Presumed or proven spinal instability mandated supine positioning and midline laparotomy, with medial visceral rotation utilized for proximal injuries. Aortoiliac injuries requiring repair were accompanied by significant distal intraluminal prolapse of dissected intima, with varying degrees of obstruction. Conduit selection was dictated by the presence of enteric contamination and the rapid availability of an autologous conduit. The sole neurologic deficit was irreparable at presentation. CONCLUSIONS: Seat belt aortoiliac injuries in pediatric patients require prompt multidisciplinary evaluation. Evidence of contained aortoiliac transection, major branch vessel avulsion, and bowel perforation mandates immediate exploration, which generally precedes spinal interventions. Lesser degrees of aortoiliac injuries have been managed with surveillance, but long-term follow-up is needed to fully validate this approach.

Thermodynamic interference with bile acid demicelleization reduces systemic entry and injury during cholestasis.

Bile acids (BA), with their large hydrophobic steroid nucleus and polar groups are amphipathic molecules. In bile, these exist as micelles above their critical micellar concentration (CMC). In blood at low concentrations, these exist as monomers, initiating cellular signals. This micellar to monomer transition may involve complex thermodynamic interactions between bile salts alone or with phospholipids, i.e. mixed micelles and the aqueous environment. We therefore went on to test if therapeutically relevant changes in temperature could influence micellar behavior of bile salts, and in turn whether this affected the biological responses in cells, and in vivo. Sodium taurocholate (STC) belongs to a major class of bile salts. STC has a CMC in the 5-8 mM range and its infusion into the pancreatic duct is commonly used to study pancreatitis. We thus studied micellar breakdown of STC using isothermal titration calorimetry (ITC), dynamic light scattering and cryogenic transmission electron microscopy. Under conditions relevant to the in vivo environment (pH 7.4, Na 0.15 M), ITC showed STC to have a U shaped reduction in micellar breakdown between 37 °C and 15 °C with a nadir at 25 °C approaching ≈90% inhibition. This temperature dependence paralleled pancreatic acinar injury induced by monomeric STC. Mixed micelles of STC and 1-palmitoyl, 2-oleyl phosphatidylcholine, a phospholipid present in high proportions in bile, behaved similarly, with ≈75% reduction in micellar breakdown at 25 °C compared to 37 °C. In vivo pancreatic cooling to 25 °C reduced the increase in circulating BAs after infusion of 120 mM (5%) STC into the pancreatic duct, and duct ligation. Lower BA levels were associated with improved cardiac function, reduced myocardial damage, shock, lung injury and improved survival independent of pancreatic injury. Thus micellar breakdown of bile salts is essential for their entry into the systemic circulation, and thermodynamic interference with this may reduce their systemic entry and consequent injury during cholestasis, such as from biliary pancreatitis.

Imaging in blunt cardiac injury: Computed tomographic findings in cardiac contusion and associated injuries.

BACKGROUND: Blunt cardiac injury (BCI) may manifest as cardiac contusion or, more rarely, as pericardial or myocardial rupture. Computed tomography (CT) is performed in the vast majority of blunt trauma patients, but the imaging features of cardiac contusion are not well described. PURPOSE: To evaluate CT findings and associated injuries in patients with clinically diagnosed BCI. MATERIALS AND METHODS: We identified 42 patients with blunt cardiac injury from our institution's electronic medical record. Clinical parameters, echocardiography results, and laboratory tests were recorded. Two blinded reviewers analyzed chest CTs performed in these patients for myocardial hypoenhancement and associated injuries. RESULTS: CT findings of severe thoracic trauma are commonly present in patients with severe BCI; 82% of patients with ECG, cardiac enzyme, and echocardiographic evidence of BCI had abnormalities of the heart or pericardium on CT; 73% had anterior rib fractures, and 64% had pulmonary contusions. Sternal fractures were only seen in 36% of such patients. However, myocardial hypoenhancement on CT is poorly sensitive for those patients with cardiac contusion: 0% of right ventricular contusions and 22% of left ventricular contusions seen on echocardiography were identified on CT. CONCLUSION: CT signs of severe thoracic trauma are frequently present in patients with severe BCI and should be regarded as indirect evidence of potential BCI. Direct CT findings of myocardial contusion, i.e. myocardial hypoenhancement, are poorly sensitive and should not be used as a screening tool. However, some left ventricular contusions can be seen on CT, and these patients could undergo echocardiography or cardiac MRI to evaluate for wall motion abnormalities.