Comparing posteroanterior with lateral and anteroposterior chest radiography in the initial detection of parapneumonic effusions.

BACKGROUND: It is unclear whether anteroposterior (AP) or posteroanterior with lateral (PA/Lat) chest radiographs are superior in the early detection of clinically relevant parapneumonic effusions (CR-PPEs). The objective of this study was to identify which technique is preferred for detection of PPEs using chest computed tomography (CCT) as a reference standard. METHODS: A secondary analysis of a pneumonia database was conducted to identify patients who received a CCT within 24 hours of presentation and also received AP or PA/Lat chest radiographs within 24 hours of CCT. Sensitivity and specificity were then calculated by comparing the radiographic diagnosis of PPEs of both types of radiographs compared with CCT by using the existing attending radiologist interpretation. Clinical relevance of effusions was determined by CCT effusion measurement of >2.5 cm or presence of loculation. RESULTS: There was a statistically significant difference between the sensitivity of AP (67.3%) and PA/Lat (83.9%) chest radiography for the initial detection of CR-PPE. Of 16 CR-PPEs initially missed by AP radiography, 7 either required drainage initially or developed empyema within 30 days, whereas no complicated PPE or empyema was found in those missed by PA/Lat radiography. CONCLUSIONS: PA/Lat chest radiography should be the initial imaging of choice in pneumonia patients for detection of PPEs because it appears to be statistically superior to AP chest radiography.

Airway mechanosensor behavior during application of positive end-expiratory pressure.

BACKGROUND: Positive end-expiratory pressure (PEEP) is commonly used in clinical settings. It is expected to affect the input from slowly adapting pulmonary stretch receptors (SARs), leading to altered cardiopulmonary functions. However, we know little about how SARs behave during PEEP application. OBJECTIVES: Our study aimed to characterize the behavior of SARs during PEEP application. METHODS: We recorded single-unit activities from 18 SARs in the cervical vagus nerve and examined their response to an increase of PEEP from 3 to 10 cm H2O for 20 min in anesthetized, open-chest and mechanically ventilated rabbits. RESULTS: The mean activity of the units increased immediately from 35.7 to 80.5 impulses per second at the fifth breath after increasing PEEP (n = 14, p < 0.001) and then gradually returned to 56.5 impulses per second at the end of 20 min of PEEP application (p < 0.001). In the meantime, peak airway pressure increased from 9.3 to 32.7 cm H2O, and then gradually returned to 29.4 cm H2O (n = 18; p < 0.05) after 20 min. The remaining four units ceased firing at 34.7 s (range 10-56 s) after their initial increased activity upon 10 cm H2O PEEP application. The unit activity resumed as the PEEP was returned to 3 cm H2O. CONCLUSIONS: High PEEP stimulates SARs and SAR activity gradually returns towards the baseline via multiple mechanisms including receptor deactivation, neural habituation and mechanical adaptation. Understanding of the sensory inputs during PEEP application will assist in developing better strategies of mechanical ventilation.

Methicillin-resistant Staphylococcus aureus induced reactive arthritis treated with systemic corticosteroid.

Reactive arthritis consists of the classic clinical triad of arthritis, urethritis and conjunctivitis generally occurring within 6 weeks of an infection, typically of the gastrointestinal or genitourinary systems. Staphylococcus aureus is not usually implicated in this condition. Staphylococcal septicemia, while frequently associated with arthralgia, has rarely been associated with a sterile arthritis, although it infrequently results in septic arthritis. It is important to consider reactive arthritis, rather than solely an infectious cause of joint effusions, and arthropathy in a patient with a preceding or ongoing Staphylococcal infection. We report a case of reactive arthritis, in a human leukocyte B27-positive patient, following a recurrent bacterial prostatitis caused by methicillin-resistant S aureus.

Acute myocardial infarction in hospitalized patients with community-acquired pneumonia.

BACKGROUND: An epidemiological link between respiratory infection and acute myocardial infarction (AMI) has been suggested, and recent data indicate that there is an association between AMI and pneumococcal community-acquired pneumonia (CAP) in hospitalized patients. The objective of this study was to investigate the association of AMI with the severity of pneumonia at hospitalization and clinical failure during hospitalization among patients with CAP. METHODS: An observational, retrospective study involving consecutive patients hospitalized with CAP was performed at the Veterans Hospital of Louisville, Kentucky. Patients admitted to the intensive care unit were defined as having severe CAP. Clinical failure was defined as the development of respiratory failure or shock. AMI was diagnosed on the basis of abnormal troponin levels and electrocardiogram findings. Propensity-adjusted models that controlled for clinical and nonclinical factors were used to investigate the association between AMI and pneumonia severity index and between AMI and clinical failure. RESULTS: Data for a total of 500 patients were studied. At hospital admission, AMI was present in 13 (15%) of 86 patients with severe CAP. During hospitalization, AMI was present in 13 (20%) of 65 patients who experienced clinical failure. Following risk adjustment, significant associations were discovered between AMI and the pneumonia severity index score (modeled with a restricted cubic spline) (P = .05) and between AMI and clinical failure (P = .04). CONCLUSIONS: A combined diagnosis of CAP and AMI is common among hospitalized patients with severe CAP. In cases in which the clinical course of a hospitalized patient with CAP is complicated by clinical failure, AMI should be considered as a possible etiology.

Pure red-cell aplasia secondary to pregnancy, characterization of a syndrome.

The aim of this study was to characterize the syndrome of pure red-cell aplasia (PRCA) secondary to pregnancy. All published cases of PRCA induced by pregnancy were reviewed. Additionally, we reported a patient who developed PRCA on three occasions; two were triggered by pregnancy and one after medroxyprogesterone administration. Ten patients with 13 pregnancy-induced PRCA episodes were reported. The PRCA occurred at any gestational age. All patients received blood transfusions, and six of them were treated corticosteroids. The PRCA resolved in all subjects postpartum. Five women had subsequent pregnancies; three were complicated by PRCA, one was normal, and one had spontaneous abortion without PRCA. One subject developed a PRCA after long-term exposure to medroxyprogesterone. Infant blood values were normal in the nine reported cases. Pregnancy-induced PRCA is a self-limited syndrome with a high risk for relapse during subsequent pregnancies. It can be managed by blood transfusions. Progestins might cause PRCA in these women.