Pulmonary infarction in acute pulmonary embolism.

Pulmonary infarction results from occlusion of the distal pulmonary arteries leading to ischemia, hemorrhage and ultimately necrosis of the lung parenchyma. It is most commonly caused by acute pulmonary embolism (PE), with a reported incidence of around 30%. Following an occlusion of the pulmonary artery, the bronchial arteries are recruited as primary source of perfusion of the pulmonary capillaries. The relatively higher blood pressure in the bronchial circulation causes an increase in the capillary blood flow, leading to extravasation of erythrocytes (i.e. alveolar hemorrhage). If this hemorrhage cannot be resorbed, it results in tissue necrosis and infarction. Different definitions of pulmonary infarction are used in literature (clinical, radiological and histological), although the diagnosis is nowadays mostly based on radiological characteristics. Notably, the infarcted area is only replaced by a fibrotic scar over a period of months. Hence and formally, the diagnosis of pulmonary infarction cannot be confirmed upon diagnosis of acute PE. Little is known of the impact and relevance of pulmonary infarction in acute PE, and whether specific management strategies should be applied to prevent and/or treat complications such as pain, pneumonia or post-PE syndrome. In this review we will summarize current knowledge on the pathophysiology, epidemiology, diagnosis and prognosis of pulmonary infarction in the setting of acute PE. We highlight the need for dedicated studies to overcome the current knowledge gaps.

Prevalence of incidental pulmonary nodules on computed tomography of the thorax in trauma patients.

BACKGROUND/AIMS: Lung cancer is the third leading cause of death in high-income countries. Early detection leads to improved clinical outcomes, with evidence showing that lung cancer screening reduces lung cancer mortality. Knowledge of the population prevalence of pulmonary nodules affects the efficacy and cost-effectiveness of a local screening programme. METHODS: We performed a retrospective review of our trauma database looking for the prevalence of incidental pulmonary nodules on computed tomography of the thorax. Prevalence of nodules and follow up according to Fleischner Guidelines were reviewed. RESULTS: Two hundred and forty-eight patients underwent a computed tomography thorax as part of their trauma assessment. 8.5% (21/248) had incidental pulmonary nodules. Eighty-one per cent of these (17/21) required follow up according to the Fleischner Society Guidelines. One was subsequently diagnosed with primary lung cancer, one with metastatic sigmoid cancer and one with invasive aspergillus. CONCLUSIONS: Incidental pulmonary nodules are common in the general population. This has implications for possible lung cancer screening recommendations in the Australian population. Referral and/or review systems are essential to ensure adequate follow up of incidental findings, as it is likely some patients are not receiving adequate follow up at present.

Use and abuse of faecal occult blood tests in an acute hospital inpatient setting.

BACKGROUND/AIMS: The role of the faecal occult blood test (FOBT) is untested. The aims of this study were to define the use of FOBT in a general hospital setting and to determine its influence on patient management. METHODS: Case notes and laboratory reports were retrospectively reviewed in all FOBTs performed in 2006 across three acute hospitals, with specific reference to clinical setting, indication, influence over clinical decision-making and management. Both guaiac and immunological tests were performed on all specimens. RESULTS: A total of 330 patients aged 2-104 (mean 74) years, 47% men, had 461 tests performed. A positive result was recorded in one or both tests in 64% of patients. Evidence of dietary restriction was found in only eight (2%) of patients and 218 (66%) patients took one or more medications that could have caused a false positive result. Indications were mostly for overt or suspected gastrointestinal blood loss with or without anaemia and/or iron deficiency, but 5% were for non-bloody diarrhoea and 3% screening for colorectal cancer. Patient care was adversely affected or delayed in 54 patients (16%), mostly because of the result being the stimulus for the decision to refer or not for endoscopy. Only one was considered appropriate as a screening test for colorectal cancer. CONCLUSIONS: The FOBT was applied in clinically inappropriate settings without consideration to confounding issues, and often led to inappropriate clinical decisions with considerable cost to hospital and patient. There is no place for FOBT in an acute hospital setting.