Bronchiolitis: A Practical Approach for the General Radiologist.

Radiologists consciously or unconsciously encounter bronchiolitis on images frequently. The purpose of this article is to simplify the concept of bronchiolitis to facilitate the formulation of a succinct and accurate differential diagnosis and suggest potential causes for the imaging findings. Direct and indirect signs of bronchiolitis that are seen on computed tomographic images are detailed. The most common causes of bronchiolitis are covered, including several distinct entities to be considered in specific clinical scenarios. In order of prevalence, the top two causes of bronchiolitis are infection and aspiration. Less common entities include respiratory bronchiolitis and hypersensitivity pneumonitis, which tend to manifest with ground-glass centrilobular nodules. Some types of bronchiolitis affect specific ethnic groups or are associated with a characteristic clinical history. For example, diffuse panbronchiolitis typically affects Japanese subjects. Constrictive bronchiolitis should be considered in lung transplant recipients with ongoing rejection. Given the high frequency of bronchiolitis, radiologists should develop a systematic approach to both cellular and constrictive bronchiolitis. Recognition of specific clinical or imaging characteristics may be sufficient for providing a relevant differential diagnosis. ©RSNA, 2017.

The diaphragmatic crura and retrocrural space: normal imaging appearance, variants, and pathologic conditions.

The retrocrural space (RCS) is a small triangular region within the most inferior posterior mediastinum bordered by the two diaphragmatic crura. Multiplanar imaging modalities such as computed tomography and magnetic resonance imaging allow evaluation of the RCS as part of routine examinations of the chest, abdomen, and spine. Normal structures within the retrocrural region include the aorta, nerves, the azygos and hemiazygos veins, the cisterna chyli with the thoracic duct, fat, and lymph nodes. There is a wide range of normal variants of the diaphragmatic crura and of structures within the RCS. Diverse pathologic processes can occur within this region, including benign tumors (lipoma, neurofibroma, lymphangioma), malignant tumors (sarcoma, neuroblastoma, metastases), vascular abnormalities (aortic aneurysm, hematoma, azygos and hemiazygos continuation of the inferior vena cava), and abscesses. An understanding of the anatomy, normal variants, and pathologic conditions of the diaphragmatic crura and retrocrural structures facilitates diagnosis of disease processes within this often overlooked anatomic compartment.

Mucoid impactions: finger-in-glove sign and other CT and radiographic features.

Mucoid impaction is a relatively common finding at chest radiography and computed tomography (CT). Both congenital and acquired abnormalities may cause mucoid impaction of the large airways that often manifests as tubular opacities known as the finger-in-glove sign. The congenital conditions in which this sign most often appears are segmental bronchial atresia and cystic fibrosis. The sign also may be observed in many acquired conditions, include inflammatory and infectious diseases (allergic bronchopulmonary aspergillosis, broncholithiasis, and foreign body aspiration), benign neoplastic processes (bronchial hamartoma, lipoma, and papillomatosis), and malignancies (bronchogenic carcinoma, carcinoid tumor, and metastases). To point to the correct diagnosis, the radiologist must be familiar with the key radiographic and CT features that enable differentiation among the various likely causes. CT is more useful than chest radiography for differentiating between mucoid impaction and other disease processes, such as arteriovenous malformation, and for directing further diagnostic evaluation. In addition, knowledge of the patient's medical history, clinical symptoms and signs, and predisposing factors is important.

Strongyloides stercoralis en la médula ósea de una persona que vive con VIH: reporte de caso

Strongyloides stercoralis es un nemátodo que se caracteriza por causar infección intestinal, usualmente asintomática, en pacientes inmunocompetentes. Sin embargo, en aquellos que viven con VIH, y de acuerdo con su estado inmune, puede generar un síndrome de hiperinfección con complicaciones diversas por diseminación a diferentes órganos. Se presenta el caso de un paciente de 30 años con diagnóstico de novo de infección por el virus de la inmunodeficiencia humana, con documentación de enfermedad linfoproliferativa. En los estudios complementarios se documenta la presencia de Strongyloides stercoralis de manera inusual en la médula ósea. A pesar de contar con un recuento de linfocitos T CD4+ mayor a 400 células/ µL y de haberse iniciado el manejo para esta condición con ivermectina, el paciente fallece por un estado séptico asociado al síndrome de hiperinfección, por lo cual se considera que este es un caso inusitado que obliga al clínico a tener en cuenta la presencia del nemátodo en pacientes que viven con VIH.

Summary Strongyloides stercoralis is a nematode that is characterized by causing a usually asymptomatic intestinal infection in immunocompetent individuals. However, in patients living with HIV and depending on their immune status, it can generate a hyperinfection syndrome with various complications due to dissemination to different organs. We present the case of a 30-year-old patient with a de novo diagnosis of human immunodeficiency virus infection and lymphoproliferative disease. Within the laboratory workup, the presence of Strongyloides stercoralis was documented in the bone marrow. Despite having a CD4+ T lymphocyte count greater than 400 cells/microliter and having started treatment for this condition with ivermectin, the patient died due to a septic state associated with hyperinfection syndrome, which is why this is considered an unusual case that alerts the clinician to take into account the presence of the nematode in patients living with HIV.