CT Findings of Varicella Pneumonia After Lung Transplantation

Atypical presentation of varicella-zoster virus reactivation in a lung transplant patient: a case report

Background. Varicella-zoster virus (VZV) is a human neurotropic virus which commonly causes infection during childhood, presenting as chickenpox. Later in life it may reactivate as herpes zoster. We report a rare manifestation of reactivation of VZV infection presenting as cutaneous vasculitis and varicella pneumonia in a lung transplant recipient. Case presentation. A 65-year-old man was lung transplanted bilaterally for emphysema and had repeated posttransplant chest infections and colonization with Pseudomonas aeruginosa. Nine months post-transplant he presented with dyspnoea and a cutaneous vasculitis-like eruption with a predilection over face, thorax and distal extremities. Initially, VZV reactivation was not suspected due to absence of the typical vesicular eruptions. The diagnosis was confirmed by VZV PCR from the swabs of the ulcer after skin punch biopsy of a lesion and from bronchoalveolar lavage (BAL). The histology of skin biopsy demonstrated epithelial damage and vascular damage but no typical epithelial virus associated changes. The patient responded to antiviral therapy with total remission of rash and VZV DNA was finally not detectable from repeated BAL after 29 days of therapy. However, the pulmonary radiological features and dyspnoea persisted due to reasons possibly unrelated to the VZV infection. Conclusion. Had it not been for the patient to mention the resemblance of the vasculitic rash with his primary VZV infection, the diagnosis would easily have been overlooked. In this case, the biopsy did not show typical histopathologic findings of VZV-vasculitis. What led the diagnosis was a PCR from the wound swab taken after the punch biopsy. This case serves as a reminder for atypical presentation of common conditions in immunosuppressed patients and that extensive diagnostic sampling may be warranted in this group.

Radiographic and CT Features of Viral Pneumonia

Viruses are the most common causes of respiratory infection. The imaging findings of viral pneumonia are diverse and overlap with those of other nonviral infectious and inflammatory conditions. However, identification of the underlying viral pathogens may not always be easy. There are a number of indicators for identifying viral pathogens on the basis of imaging patterns, which are associated with the pathogenesis of viral infections. Viruses in the same viral family share a similar pathogenesis of pneumonia, and the imaging patterns have distinguishable characteristics. Although not all cases manifest with typical patterns, most typical imaging patterns of viral pneumonia can be classified according to viral families. Although a definite diagnosis cannot be achieved on the basis of imaging features alone, recognition of viral pneumonia patterns may aid in differentiating viral pathogens, thus reducing the use of antibiotics. Recently, new viruses associated with recent outbreaks including human metapneumovirus, severe acute respiratory syndrome coronavirus, and Middle East respiratory syndrome coronavirus have been discovered. The imaging findings of these emerging pathogens have been described in a few recent studies. This review focuses on the radiographic and computed tomographic patterns of viral pneumonia caused by different pathogens, including new pathogens. Clinical characteristics that could affect imaging, such as patient age and immune status, seasonal variation and community outbreaks, and pathogenesis, are also discussed. The first goal of this review is to indicate that there are imaging features that should raise the possibility of viral infections. Second, to help radiologists differentiate viral infections, viruses in the same viridae that have similar pathogenesis and can have similar imaging characteristics are shown. By considering both the clinical and radiologic characteristics, radiologists can suggest the diagnosis of viral pneumonia. ^©RSNA, 2018.

Thoracic lymphadenopathy in benign diseases: A state of the art review

Lymphadenopathy is a common radiological finding in many thoracic diseases and may be caused by a variety of infectious, inflammatory, and neoplastic conditions. This review aims to describe the patterns of mediastinal and hilar lymphadenopathy found in benign diseases in immunocompetent patients. Computed tomography is the method of choice for the evaluation of lymphadenopathy, as it is able to demonstrate increased size of individual nodes, abnormalities of the interface between the mediastinum and lung, invasion of surrounding fat, coalescence of adjacent nodes, obliteration of the mediastinal fat, and hypo- and hyperdensity in lymph nodes. Intravenous contrast enhancement may be needed to help distinguish nodes from vessels. The most frequent infections resulting in this finding are tuberculosis and fungal disease (particularly histoplasmosis and coccidioidomycosis). Sarcoidosis is a relatively frequent cause of lymphadenopathy in young adults, and can be distinguished from other diseases - especially when enlarged lymph nodes are found to be multiple and symmetrical. Other conditions discussed in this review are silicosis, drug reactions, amyloidosis, heart failure, Castleman's disease, viral infections, and chronic obstructive pulmonary disease.

Varicella zoster virus pneumonitis and brainstem encephalitis without skin rash in an immunocompetent adult

Varicella zoster virus (VZV) pneumonitis and brainstem encephalitis developed in an immunocompetent adult without rash. Chest computed tomography exhibited nodularity; lung biopsy revealed multinucleated giant cells, Cowdry A inclusions, VZV antigen, and DNA. Varicella zoster virus central nervous system disease was verified by cerebrospinal fluid (CSF) anti-VZV IgG antibody with reduced serum/CSF ratios.

Pulmonary Interstitium

The first step in the radiographic evaluation of interstitial lung disease begins with a fundamental knowledge of the anatomy of the pulmonary interstitium and the different patterns of disruption. The anatomy of the pulmonary interstitium as demonstrated on CT of the chest with high resolution cuts is largely essential to establish the various radiological patterns that define interstitial lung disease such as the tree-in-bud, ground-glass opacity, crazy -paving, etc.

Viral pneumonias in immunocompromised adult hosts

Viral infections have always been considered pediatric diseases. However, viral pneumonia has become an important cause of morbidity and mortality in immuncompromised adults. Improved diagnostic techniques, such as the introduction of highly sensitive nucleic acid amplification tests, have not only allowed us to discover new viruses but also to determine the etiology of viral pneumonia in immunocompromised adult hosts. Unfortunately, only a few antiviral agents are available. Thus, early diagnosis and treatment are crucial to patient outcome. In this article, we review the most common viruses that have been implicated as etiologic agents of viral pneumonia in immunocompromised adults. We discuss the epidemiologic characteristics and clinical presentation of these viral infections and the most appropriate diagnostic approaches and therapies when available.