bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Cardiac Imaging in Women
Authors: Taqueti Viviany R. , Souza Ana Carolina do A. H. de
Published: February 2024

Heart disease is the number-one cause of death in women worldwide, and important sex differences in the rates of diagnosis, utilization of care, response to therapy and clinical outcomes have been described. Conventional diagnostic testing approaches in the evaluation of ischemic heart disease, which were designed primarily for identification of obstructive CAD, can lead to under- or over-testing in women without differentiating those most at risk. Unique factors related to the presentation, diagnosis, and underlying pathophysiology of ischemic heart disease in women underscore the need for a more tailored risk assessment strategy. Extensive evidence supports that MPI with SPECT and PET can effectively risk stratify women with ischemic heart disease. This chapter reviews how advances in nuclear cardiology techniques, including the addition of (1) absolute quantification of coronary blood flow and reserve, (2) multiparametric imaging approaches with MPI and CT, and (3) strategies to reduce radiation dose with the use of ultra-low-dose protocols involving stress-only imaging, solid-state detector SPECT, and PET, are being applied to better capture pathologic phenotypes prevalent in women, including ischemia with no obstructive CAD and coronary microvascular dysfunction, which may be important contributors to their morbidity and mortality.
Imaging Dyssynchrony
Authors: Gimelli Alessia , Liga Riccardo
Published: February 2024

In recent decades, the evaluation of cardiac mechanical dyssynchrony has gained increasing relevance, with solid evidence demonstrating the highly negative impact of asynchronous mechanical activation on cardiac dynamics and, ultimately, patient prognosis. In this context, cardiac resynchronization therapy has been demonstrated as a lifesaving therapy in patients with heart failure and cardiac dyssynchrony. Phase analysis on nuclear cardiac imaging offers the chance to assess the presence and quantify the extent of mechanical dyssynchrony, allowing the selection of patients who would likely benefit from cardiac resynchronization therapy by identifying the region of latest mechanical activation where the pacing lead should be positioned. The present chapter will describe the possible use of nuclear cardiac imaging for the evaluation of cardiac mechanical dyssynchrony, outlining the methodologic background as well as the advantages and limitations of each technique.
Imaging Cardiac and Vascular Inflammation
Authors: Tavakoli Sina , Sadeghi Mehran M.
Published: February 2024

Molecular imaging is an emerging approach that allows clinicians to noninvasively obtain quantitative information about the inflammatory processes that are involved in the pathogenesis of cardiovascular diseases. Therefore, it can serve as a precision medicine tool for early diagnosis and risk stratification of patients as well as for monitoring the response to preventive and/or therapeutic interventions. In this chapter the authors review the major approaches that have been successfully utilized for targeted imaging of various aspects of inflammation in preclinical or clinical settings. They then focus on the specific imaging strategies that have been employed in clinical studies to evaluate cardiovascular pathologies.
Evolving Role of Echocardiography, Cardiac CT, and Cardiac MRI in CAD
Authors: Ng Arnold C. T. , Delgado Victoria , Bax Jeroen J.
Published: February 2024

There have been significant advances in echocardiography, cardiac CT, and cardiac MRI in the assessment of CAD in recent years. In echocardiography, quantification of LV systolic function by global longitudinal strain analysis has been shown to be superior to LVEF with lower measurement variability and greater sensitivity for detecting subclinical myocardial dysfunction, and it is a superior prognosticator for cardiovascular morbidity and all-cause mortality. Cardiac CT has evolved beyond a “traditional” anatomic test to permit the functional assessment of the hemodynamic significance of coronary stenosis using phaemacologic stress perfusion and/or fractional flow reserve. Finally, there has been considerable interest in quantifying extracellular volume in cardiac magnetic resonance imaging as a surrogate marker for diffuse myocardial interstitial fibrosis.
Hybrid Imaging: SPECT/CCTA, PET/MR, and SPECT Calcium Score
Authors: Kaufmann Philipp A. , Gaemperli Oliver , Buechel Ronny R.
Published: February 2024

Appropriate treatment of patients with stable coronary artery disease relies on the assessment of coronary anatomy and myocardial perfusion, which can be achieved with cardiac hybrid imaging either using dedicated hybrid scanners integrating two imaging modalities (e.g., SPECT/CT or PET/CT) or with appropriate fusion software that enables accurate co-registration of imaging data originating from standalone scanners. Both allow of these for accurate integration of anatomic and functional information, and hybrid imaging has been shown to yield superior diagnostic accuracy compared to single modalities, to have a significant impact on downstream resource utilization, and to provide incremental information on patient prognosis.
Nuclear Cardiology Guidelines and Appropriate Use Criteria
Authors: Christian Timothy F.
Published: February 2024

Under governmental pressure from potential over-utilization of imaging, physicians recognized they needed to set guidelines that best promoted optimal use for patient benefit. Nuclear cardiology was at the forefront of this effort, adopting one of the first sets of appropriateness criteria. These rely heavily on conditional probability. They also require an understanding of incremental value and cost-effectiveness. The strong theme for the majority of the guidelines, which are based on evidence from clinical trials and the clinical literature, is that intermediate-risk patients benefit the most from noninvasive testing. Consequently, understanding how clinical risk is assigned is another critical piece of knowledge. Another key component is symptomatic versus asymptomatic patients, where appropriateness is strongly in favor for testing patients with symptoms. The clinical guidelines have an indication category as well as a level-of-evidence rating. Appropriate use criteria were developed subsequent to the initial clinical guidelines. These were intended to be more applicable to individual patients and reflect what the average reasonable clinician might order and less reliant on clinical trials. Both the guidelines and the appropriate use criteria have evolved extensively and are now incorporated into specific disease states rather than by imaging modality. European guidelines have followed much of the same path but are generally more inclusive of other imaging modalities.
Statistics in Nuclear Imaging
Authors: Morgan Charity J. , Hartzes Anastasia M.
Published: February 2024

Nuclear cardiac imaging has both diagnostic and prognostic applications. The statistical properties of diagnostic tools within the field of nuclear medicine must be well understood in order to ensure their proper use. Which statistical methods are appropriate for a diagnostic test will depend on whether the test or procedure returns a qualitative or quantitative result. For qualitative tests, the authors review true or false positives and negatives and provide definitions of key concepts such as sensitivity, specificity, and predictive values. For quantitative tests, the Bland–Altman limits of agreement, among other methods, may be used to assess the agreement between tests. The authors also discuss the application of meta-analysis to diagnostic tests. Assessing the prognostic value of a measure obtained via nuclear imaging often involves applying survival analysis methods. This chapter reviews Kaplan–Meier estimators, the log-rank test, and Cox proportional hazards modeling. Formulas and worked examples provide demonstrations of these concepts.
Nuclear Imaging in Developing Countries
Authors: Peix Amalia , Paez Diana , Vitola Joao V. , Orellana Pilar , Dondi Maurizio
Published: February 2024

The burden of cardiovascular disease is ever-growing, and it represents the most common cause of death worldwide. Notably, 80% of deaths from cardiovascular disease occur in low- and middle-income countries. Nuclear cardiology has a well-established role in the management of patients with cardiovascular disease and is being increasingly integrated into health care systems. However, its availability varies across countries. This chapter covers the nuclear cardiology situation in low- and middle-income countries, including infrastructure, human resources, types of cardiac studies, utilization of hybrid imaging, differences in radiation exposure, and opportunities for collaboration with the United Nations system (mainly the International Atomic Energy Agency), as well as with scientific local, regional, and international societies, to increase the practice of high-quality nuclear cardiology in low- and middle-income countries.
Regulation of Myocardial Blood Flow
Authors: Gewirtz Henry
Published: February 2024

A comprehensive review of the physiology of the coronary circulation is beyond the scope of any book chapter. Accordingly, an effort will be made here to present just the basic principles that all practitioners of nuclear cardiology should understand. It is useful to consider the normal circulation first and then move to myocardial flow regulation in the setting of atherosclerotic coronary artery disease and disease of the coronary microvasculature, which very often but not always is associated with coronary artery disease. The Chapter will also review invasive indices used for the assessment of the coronary circulation including CFR, FFR, iFR and IMR, and the non-invasive PET indices of MBF (at rest and stress), MFR, RFR, and FFR, as well as CT-derived MBF and FFR.
Measurement of Myocardial Blood Flow by SPECT
Authors: de Oliveira Brito Juliana Brenande , Small Gary R. , Ascah Kathryn J. , Wells R. Glenn , Ruddy Terrence D.
Published: February 2024

Stress MPI with SPECT and PET is widely used for diagnosis and determining prognosis in patients with suspected or known CAD. However, a major limitation of MPI is the use of relative perfusion for diagnosis of obstructive CAD and leads to underestimation of the extent of obstructive CAD. However, MBF and MFR can be measured with PET and provide additional diagnostic and prognostic value over relative PET MPI. Similarly, SPECT measurement of MBF may improve the clinical value of SPECT and greatly increase the availability and use of MBF with MPI. The accuracy of CZT SPECT measurement of MBF has been validated in clinical evaluations in patients undergoing coronary angiography and PET imaging. Reduced global stress MBF and MFR can identify the presence of severe MVD. Regional reductions in stress MBF and MFR have high diagnostic accuracy for specific vessel CAD. Reduced global and regional SPECT MFR can predict reduced global and regional PET MFR. SPECT measurement of MBF has good day-to-day repeatability and interobserver variability. We describe the use of SPECT MBF at the University of Ottawa Heart Institute, including image acquisition and processing and clinical interpretation of test results with case examples. The clinical use of SPECT MBF is in the early stages of implementation. Protocols including radiotracers, camera systems and software need to be standardized. Multicenter studies are necessary to better define the diagnostic value of CZT SPECT MBF for obstructive CAD and the incremental prognostic value of SPECT MBF measurement compared to relative MPI.
Pharmacologic Stress Testing
Authors: Andrikopoulou Efstathia , Iskandrian Ami E. , Hage Fadi G.
Published: February 2024

Stress MPI using SPECT is widely used for CAD detection and risk stratification. While exercise is the preferred mode of stress in the majority of patients, pharmacologic stress is recommended for patients who have exercise limitations and patients with ventricular pre-excitation, LBBB, or artificially paced rhythms. Pharmacologic stress agents produce coronary hyperemia by completely different sets of mechanisms than exercise, but the hyperemia achieved with these agents is at least as intense as that achieved by maximal exercise. This chapter will discuss the pharmacology, mechanisms of action, hemodynamic effects, safety, and side effect profiles of the pharmacologic stress agents used for MPI and the protocols used with these agents either alone or when combined with exercise. The chapter also includes a description of the utility of pharmacologic stress MPI data on clinical management.
SPECT MPI and Risk Assessment Before Non-Cardiac Surgery
Authors: Fisher Daniel C. , Phillips Lawrence M.
Published: February 2024

SPECT MPI is routinely used to evaluate patients with chest pain, both for diagnostic and prognostic purposes. The evaluation of patients prior to non-cardiac surgery can also provide an opportunity to evaluate both symptomatic and asymptomatic patients for the presence of obstructive coronary artery disease. This chapter reviews the most recent ACC/AHA guidelines for preoperative risk evaluation, particularly as they pertain to the role of stress testing with nuclear imaging. It also includes tools that are recommended for risk stratification in patients who are preparing for non-cardiac surgery as well as test selection in such patients. Finally, it will discuss the application of these results with respect to pharmacologic therapy and invasive evaluation with coronary angiography.
Role of PET in Diagnosis and Risk Assessment in Patients with Known or Suspected CAD
Authors: Wiefels Christiane , Mc Ardle Brian A. , Renaud Jennifer M. , deKemp Robert A. , Beanlands Rob S. B. , Promislow Steven
Published: February 2024

The use of cardiac PET MPI for evaluating CAD continues to increase due to more widespread availability of PET systems and a shifting focus toward minimizing patient radiation exposure from diagnostic testing. Ongoing advances in camera technology and radiotracer development coupled with consistent attenuation correction contribute to a higher diagnostic accuracy compared to other noninvasive means of evaluating for CAD, such as SPECT imaging. In particular, the ability to quantify myocardial blood flow further increases sensitivity for the detection of CAD and provides incremental prognostic value. This chapter provides a review of PET MPI and myocardial blood flow for diagnosis and risk assessment in patients with known or suspected CAD, focusing on imaging protocols and interpretation, prognosis, recent expanded use and applications of myocardial blood flow quantification, and utilization of PET imaging to guide clinical decision-making. Potential future directions for PET imaging are also highlighted.
Radionuclide Imaging in Heart Failure
Authors: Shpilsky Daniel , Soman Prem
Published: February 2024

Radionuclide imaging techniques are widely available and are applicable irrespective of body habitus, cardiac rhythm, renal function, the presence of implanted cardiac devices, or allergy to iodinated contrast. Nuclear cardiac imaging can be applied with advantage at several stages in the evaluation and management of the heart failure patient, including the assessment of etiology, selection of patients for coronary revascularization, and the measurement and serial evaluation of left ventricular function. Imaging with SPECT or PET can identify specific pathophysiologic states of CAD-related LV systolic dysfunction and thus differentiate ischemic cardiomyopathy from nonischemic cardiomyopathy coexisting with CAD. In addition, radionuclide approaches have a unique role in the evaluation of specific heart failure etiologies such as amyloidosis, where Tc-99m pyrophosphate imaging has been transformative, and sarcoidosis and post-transplant allograft vasculopathy. Evolving applications are likely to expand the utility of radionuclide imaging in heart failure.
Esophageal Motility
Authors: Codipilly Chamil C. , Ravi Karthik
Published: February 2024

The esophagus is the conduit for oral contents to pass from the oropharynx into the stomach. An intricate network of neuromuscular processes allows for the propulsion of food into the stomach while avoiding the passage of boluses into the respiratory system and inhibiting the reflux of gastric contents into the esophagus. Esophageal dysmotility manifests mainly as dysphagia or gastroesophageal reflux disease, although in rare instances it may also result in chest pain and discomfort. This chapter reviews the normal physiology of swallowing and discusses the pathophysiology, diagnostic evaluation, and management of esophageal motility disorders.
Peptic Ulcer Disease
Authors: Hansel Stephanie L.
Published: February 2024

A peptic ulcer is a persistent break in the gastrointestinal mucosa of the stomach or duodenum that is at least 5 mm and penetrates through the muscularis mucosa. At endoscopy, an ulcer with perceivable depth should be readily apparent. Smaller, shallower mucosal breaks are erosions. Most peptic ulcers are due to Helicobacter pylori infection or the administration of nonsteroidal anti-inflammatory drugs. The term peptic ulcer disease refers to ulceration that depends in part on the acid and peptic (ie, with pepsins) activity of gastric juice. Most peptic ulcers occur in the stomach or duodenal bulb.
Gastric Neoplasms and Gastroenteric and Pancreatic Neuroendocrine Tumors
Authors: Sweetser Seth R.
Published: February 2024

Gastric neoplasms are an important contributor to cancer-related mortality. Of the various neoplasms that can affect the stomach, adenocarcinoma is the most common and accounts for up to 85% of gastric neoplasms, with 15% due to lymphomas, gastrointestinal stromal tumors, neuroendocrine tumors, and metastatic disease involving the stomach. This chapter considers the epidemiology, pathogenesis, clinical manifestation, diagnostic evaluation, treatment, and prognosis of these neoplastic diseases.
Endoscopy for the Gastroenterology Board Examination
Authors: Sawas Tarek , Bruining David H. , Storm Andrew C.
Published: February 2024

Colonoscopy is a widely used diagnostic and therapeutic tool. The goal of a screening colonoscopy is to detect and remove early neoplastic lesions to prevent the development of colorectal cancer in asymptomatic patients. Performing a high-quality colonoscopy with comprehensive mucosal visualization is essential. The following metrics have been proposed as indicators for high-quality examinations: colon preparation, cecal intubation rate, withdrawal time, and adenoma detection rate.
Inflammatory Bowel Disease: Therapy
Authors: Pardi Darrell S. , Chedid Victor G.
Published: February 2024

There are many therapies available for patients with inflammatory bowel disease (IBD). Medical therapies include aminosalicylate drugs such as sulfasalazine, olsalazine, balsalazide, and various formulations of mesalamine; antibiotics; corticosteroids; immunosuppressive medications such as azathioprine, 6-mercaptopurine, methotrexate, and cyclosporine; and biotechnology medications such as anti–tumor necrosis factor agents, anti-interleukins, anti-integrins, and other newer agents with different targets and mechanisms of action. This chapter reviews these various treatments and where they fit in the treatment algorithms for Crohn disease and ulcerative colitis. Many surgical therapies also are used in patients with IBD, although a detailed review of these options is beyond the scope of this chapter.
Inflammatory Bowel Disease: Extraintestinal Manifestations and Colorectal Cancer
Authors: Quinn Kevin P. , Raffals Laura E.
Published: February 2024

Ulcerative colitis and Crohn disease are inflammatory disorders that affect the gastrointestinal tract. However, these diseases are systemic disorders that may involve other organ systems. Extraintestinal manifestations can affect any organ system, and while in many cases these symptoms are believed to be a result of the underlying intestinal inflammation, some extraintestinal manifestations are independent of the luminal disease course. Extraintestinal manifestations may precede the diagnosis of inflammatory bowel disease. Many patients who have extraintestinal manifestations have colonic disease, and in persons with 1 extraintestinal manifestation, another extraintestinal symptom is more likely to develop.
Intestinal Infections
Authors: Khanna Sahil
Published: February 2024

Intestinal infections are common. An estimated 180 million illnesses occur annually in the US and over 1 billion cases of infectious diarrhea occur annually worldwide. Despite advances in diagnosis, supportive care, and antibiotic guidance, the mortality from these infections remains extremely high, especially in the pediatric age group. Some estimates indicate that enteric infectious diarrhea in children younger than 5 years leads to 1 death every 10 seconds. Infectious diarrhea from enteric pathogens is more common in children and in resource-limited countries than in adults in industrialized countries. The clinical features of infectious diarrhea vary, depending on whether the organism is invasive and whether the infection occurs in the small bowel or colon.
Colorectal Neoplasms
Authors: Ebner Derek W. , Kisiel John B.
Published: February 2024

Colorectal cancer (CRC) is primarily a disease of urban, industrialized societies. In the US, the lifetime risk of CRC is similar for men (4.4%) and women (4.1%). Recent data have suggested that the incidence rates of CRC may be decreasing gradually in some subgroups of the population but increasing in adults younger than 50 years. However, the mechanisms underlying these trends have not been defined completely. Several national organizations have endorsed screening and surveillance guidelines, which undoubtedly have contributed to more effective prevention of CRC.
Gastrointestinal Disease and Pregnancy
Authors: Kane Sunanda V.
Published: February 2024

Pharmacotherapy for the management of common gastrointestinal illnesses continues to evolve. Women with chronic illnesses who would have been unwilling or unable to conceive in the past are now healthy enough to consider pregnancy. In addition, many women are deferring childbearing until later in life, when polypharmacy and illness may be more common. This chapter discusses the use of medications during pregnancy according to the best available evidence. Because the amount of high-quality controlled data in pregnancy is limited, absolute safety is not guaranteed with any medication. This chapter covers the treatment of common gastrointestinal and liver diseases, the management of common gastrointestinal symptoms, and the use of medications during endoscopy.
Portal Hypertension–Related Bleeding
Authors: Hilscher Moira , Simonetto Douglas A.
Published: February 2024

Portal hypertensive bleeding encompasses a spectrum of conditions that include esophageal, gastric, and ectopic varices and portal hypertensive gastroenteropathy. Esophageal variceal hemorrhage occurs through a combination of increased portal pressure and local factors within the varix itself. Management of esophageal varices includes primary prophylaxis of variceal hemorrhage, treatment of actively bleeding varices, and prevention of variceal rebleeding (secondary prophylaxis). The choice of therapy for primary prophylaxis depends on patient preferences and includes pharmacologic therapy with nonselective β-blockers (NSBBs) or variceal band ligation, especially if NSBB therapy fails or is not tolerated by the patient. Active bleeding is best treated endoscopically.
Metabolic Liver Diseases
Authors: Cheung Angela C. , Sanchez William
Published: February 2024

Metabolic liver disease refers to inherited disorders of metabolism that manifest prominently with liver disease. The 3 major inherited disorders that cause liver disease in adults are α1-antitrypsin deficiency, Wilson disease, and hereditary hemochromatosis. All are multisystem disorders that cause liver injury by various mechanisms but which can ultimately lead to cirrhosis and complications of liver failure. Also, various inborn errors of metabolism that cause liver disease manifest during childhood. These inborn errors of metabolism are, in aggregate, a major indication for pediatric liver transplant. As more patients who have childhood syndromes with liver involvement survive into adulthood, gastroenterologists who treat adults will need to become familiar with their care; however, the childhood syndromes rarely manifest initially in adulthood.
Cholestatic Liver Disease
Authors: Eaton John E.
Published: February 2024

Cholestatic liver disease in adults may or may not show evidence of large bile duct obstruction. Drug-induced cholestasis may be the most common explanation for cholestasis, which is often self-limiting. Primary biliary cholangitis is the most common chronic cholestatic liver disease in adults, and primary sclerosing cholangitis is about half as common as primary biliary cholangitis. In contrast to primary sclerosing cholangitis, the cause of secondary sclerosing cholangitis can often be identified.
Drug-Induced Liver Injury
Authors: Mousa Omar Y. , Leise Michael D.
Published: February 2024

Despite increased awareness through the efforts of public and regulatory agencies, the syndrome known as drug-induced liver injury (DILI) is still a major public health problem in the US and the world. Moreover, it is the single most common reason for US Food and Drug Administration regulatory actions, including the removal of drugs from the marketplace. Although the frequency of this clinical syndrome is low within populations, DILI causes a significant clinical and economic burden. This chapter highlights new developments in the field of idiosyncratic DILI and provides information about DILI from acetaminophen.
Liver Disease in Pregnancy
Authors: Udompap Prowpanga , Allen Alina M.
Published: February 2024

Because most pregnant women are young and healthy, liver disease is uncommon in this population. Also, the presence of liver disease must not be confused with some of the physiologic changes of pregnancy that mimic features commonly associated with liver dysfunction (Table 35.1). Examples of physiologic changes include spider angioma and palmar erythema, which may occur in half the pregnant women because of the hyperestrogenic state, increased serum alkaline phosphatase level from placental production, and decreased albumin and hemoglobin levels with volume expansion. Increased bilirubin and transaminase levels, hepatomegaly, splenomegaly, liver tenderness, and bruits do not occur in normal pregnancy, and the clinical finding of jaundice is always abnormal.
Liver Transplantation
Authors: Mousa Omar Y. , Ilyas Sumera I.
Published: February 2024

Liver (LT) is highly effective for patients with liver failure to restore normal health and a normal lifestyle. Patient survival after LT is excellent, reaching 90% at 1 year and 77% at 5 years in the US according to the Scientific Registry of Transplant Recipients. The 5-year survival rate for living-donor LT (LDLT) recipients for 2008-2011 was 81.2%. Timely evaluation for transplant and optimization of pretransplant care is essential for the potential liver recipient. However, the demand for donor organs greatly exceeds supply. In 2019 in the US, 8,345 liver transplants were performed for patients 18 years or older, 442 (5.3%) of whom underwent LDLT.
A 45-Year-Old Man With Chronic Cough and Dyspnea on Exertion
Authors: Olson Emily M. , Kelm Diana J.
Published: February 2024

The differential diagnosis for uncontrolled asthma is broad and includes vasculitis, eosinophilic pneumonia, structural abnormalities such as vocal cord dysfunction, and infectious causes such as allergic bronchopulmonary aspergillosis among many others. Eosinophilic granulomatosis with polyangiitis should be considered when patients have uncontrolled asthma, eosinophilia and rhinosinusitis, and systemic symptoms such as neuropathy, skin lesions, or glomerulonephritis. Glucocorticoids are the mainstay of management, and often patients require long-term therapy with prednisone for asthma control.
A 59-Year-Old Woman With Episodic Dyspnea
Authors: Marty Paige K. , Niven Alexander S.
Published: February 2024

Dyspnea is a symptom with many possible causes, including upper airway pathology. Inducible laryngeal obstruction should be considered when patients have acute-onset episodic dyspnea, stridor, and difficulty with inspiration. The mainstays of treatment include optimization of other upper airway pathologic findings, speech-behavioral therapy, and management of behavioral health conditions if identified.
A 52-Year-Old Man With Suicidal Ideation and Bipolar Disorder
Authors: Gopalratnam Kavitha , Hocker Sara E.
Published: February 2024

Patients with serotonin syndrome present with the triad of mental status changes, neuromuscular abnormalities, and autonomic dysfunction after exposure to a serotonergic drug. A high degree of awareness is required for an accurate diagnosis. Prompt discontinuation of the drug and symptom management are the mainstays of therapy.
A 61-Year-Old Man With Dyspnea on Minimal Exertion
Authors: Krishna Rachana , Ryu Jay H.
Published: February 2024

Pulmonary Langerhans cell histiocytosis (PLCH) is a diffuse cystic lung disease related to smoking in adults. The disease may coexist with other smoking-related conditions, including respiratory bronchiolitis, DIP, and emphysema. Decreased Dlco is the most common finding on pulmonary function testing. Extrapulmonary involvement, mainly with bone and pituitary involvement, occurs in 10% to 15% of adults with smoking-related PLCH. Treatment of PLCH is mainly smoking cessation; rarely, corticosteroids and cladribine are used if the disease continues to progress despite smoking cessation. Complications of PLCH include spontaneous pneumothorax, pulmonary hypertension, and increased risk of malignancies.
A 67-Year-Old Woman With Progressive Dyspnea and Atypical Infiltrates
Authors: Kubbara Aahd F. , Moua Teng
Published: February 2024

Diagnosis of pulmonary amyloidosis tends to be delayed because the condition is rare and few symptoms develop, although incidental radiologic findings may be extensive. The 3 types of pulmonary amyloidosis have distinctive radiologic and clinical presentations, underlying causes, and prognoses. Nodular amyloidosis tends to be associated with a local lymphoproliferative disorder and usually carries a favorable prognosis. Diffuse alveolar septal amyloidosis is typically associated with underlying systemic disease and, with its histologic pattern of alveolar damage, tends to impair gas exchange and lead more commonly to dyspnea and hypoxemia. Tracheobronchial amyloidosis may result in airway compromise and hemoptysis. Of these, diffuse alveolar septal forms carry the worst prognosis.
A 36-Year-Old Man With Recurrent Fevers, Dry Cough, and Weight Loss
Authors: Kanj Amjad N. , Pennington Kelly M.
Published: February 2024

Tuberculosis (TB) is most common in resource-limited populations and has major public health implications. Usually, the disease arises from reactivation of a latent focus in the lungs. Prompt diagnosis and effective treatment are essential. Adjunctive corticosteroids are important in the management of tuberculous meningitis and should be considered during the first 4 weeks after antiretroviral therapy initiation in HIV-infected patients who have active TB disease and are at risk for TB-associated immune reconstitution inflammatory syndrome.
A 51-Year-Old Woman With Fever and Cough
Authors: Mudrakola Harsha V. , Skalski Joseph H.
Published: February 2024

When patients have isolated ground-glass opacities on radiography, the differential diagnosis is broad. Pneumocystis jirovecii pneumonia must be considered if a patient is immunosuppressed. In patients without HIV infection, hematologic malignancies and their therapy-related immunosuppression portend the greatest risk for Pneumocystis jirovecii pneumonia. The treatment algorithm is similar for patients with HIV infection and for patients without HIV infection.
A 56-Year-Old Man With Persistent Pneumonia
Authors: Long Cameron M. , Hoskote Sumedh S.
Published: February 2024

Unresolving pneumonia, characterized by a lack of radiographic clearance in normal lungs by 6 weeks, has a broad differential diagnosis. Malignancy occurs in 1% to 2% of patients and requires vigilance to ensure timely diagnosis. Early-stage non–small cell lung cancer is curable, and surgical resection is recommended. Advanced-stage adenocarcinoma is treatable, and life expectancy is improving, but survival is still poor (40% survival at 5 years) for patients with stage III or IV disease (6).
A 65-Year-Old Man With Shoulder Pain, Cough, and Dyspnea
Authors: Vu Ann N. , Li Heyi , Kern Ryan M.
Published: February 2024

Malignant pleural mesothelioma is a rare but aggressive primary pleural malignancy. Diagnosis often requires invasive biopsy for acquisition of sufficient tissue. Despite decades of research and multimodality therapy, the optimal treatment regimen for MPM is unclear, and the prognosis is poor. In the future, though, the use of immunotherapy and biologic agents may revolutionize treatment guidelines and improve patient survival.
A 49-Year-Old Man With Cough, Dyspnea, and Right-Sided Chest Pain
Authors: Aragon Pinto Catarina N. , Antharam Phanindra , Midthun David E.
Published: February 2024

Clinical presentation, radiologic findings, and pleural fluid analysis are essential to differentiate a simple effusion from a complicated pleural effusion or empyema and can guide therapeutic management. Cultures from pleural fluid samples help guide antibiotic therapy but are not mandatory for initiation of antibiotic therapy. False-negative culture results may occur depending on which loculation in the pleural space is aspirated and analyzed. One loculation may be serous while a neighboring loculation may contain pus. Intrapleural fibrinolytic therapy is a highly valuable management option for patients concurrently treated with antibiotics. Pleural drainage and lytic therapy can be an alternative to surgical intervention and eliminate the need for surgery for the majority of patients.
A 45-Year-Old Woman With Respiratory Failure and Septic Shock
Authors: Fonseca Fuentes Xavier E. , Shaughnessy Gaja F. , Peikert Tobias
Published: February 2024

Pleural involvement in multiple myeloma is a rare condition that is frequently associated with a poor prognosis. The diagnostic strategy includes pleural fluid cytology and electrophoresis or histologic confirmation with pleural biopsy. Management involves treatment of multiple myeloma and relief of respiratory symptoms with drainage of pleural fluid or pleurodesis.
An 81-Year-Old Man With Chronic Dyspnea and Recurrent Pleural Effusion
Authors: Norton Mark S. , Utz James P. , Kern Ryan M.
Published: February 2024

Recurrent exudative pleural effusion of unclear etiology is a commonly encountered entity with a wide differential diagnosis. Expedient evaluation and diagnosis are necessary. Pleural fluid analysis is the first step because a lymphocyte-predominant exudate is most commonly associated with malignancy or tuberculosis. Cytology is helpful, but sensitivity decreases with each subsequent sampling. Advanced cross-sectional imaging with CT of the chest is needed if a diagnosis is not made after initial evaluation and analysis of the pleural fluid. This will help in differentiating between benign and malignant pleural disease and in providing guidance for tissue acquisition. Medical pleuroscopy is a safe and effective procedure for pleural biopsy.
A 25-Year-Old Man With Sudden Onset of Severe Dyspnea
Authors: Kelly Bryan T. , Mullon John J.
Published: February 2024

Pneumothorax is a common pulmonary disease that may occur spontaneously, iatrogenically, or traumatically. Although multiple guidelines exist to guide appropriate interventions, there is no overall consensus about when conservative treatment is appropriate, when intervention is necessary, or which intervention should be performed initially. However, the most widely accepted indication for therapy is the presence of clinically significant symptoms. If an alveolopleural fistula leads to prolonged air leaks, healing usually occurs within 2 weeks, but additional interventions may be pursued to treat an unresolved leak.
A 71-Year-Old Woman With Cough, Night Sweats, and Fevers
Authors: Albitar Hasan A. , de Moraes Alice Gallo
Published: February 2024

Tuberculous pleural effusion (TPE) is an exudative effusion with a predominance of lymphocytes. When TPE is suspected, pleural fluid must be obtained and evaluated. The results of laboratory testing are usually characterized by elevated LDH concentration, low pH, and elevated protein concentration. When the clinical suspicion for TPE is high, a presumptive diagnosis can be made without pathologic confirmation when the pleural effusion has a predominance of lymphocytes and an adenosine deaminase level greater than 40 IU/L. In general, treatment of TPE is the same as standard treatment of active pulmonary tuberculosis.
A 79-Year-Old Woman With Shortness of Breath, Fatigue, Near Syncope, and Chest Tightness
Authors: McCambridge Amanda J. , Ekstein Samuel F. , Lim Kaiser G.
Published: February 2024

Pulmonary torsion is a rare but potentially life-threatening condition. It usually occurs after intrathoracic surgery or chest trauma, but it can occur spontaneously. Diagnosis is made with the use of contrast computed tomography of the chest or bronchoscopy, and urgent or emergent definitive management with thoracic surgery is usually required.
A 68-Year-Old Woman With Dyspnea and Pleuritic Chest Pain
Authors: Gary Phillip J. , Odeyemi Yewande E.
Published: February 2024

Patients presenting with acute pulmonary embolism require immediate risk stratification to determine the need for more intensive monitoring and consideration of additional therapies besides only anticoagulation. Thorough investigation can help stratify seemingly borderline cases, which, at some institutions, may be arbitrated by multidisciplinary teams. In most cases, testing for inherited thrombophilias is not warranted in the acute setting, and the use of inferior vena cava filters should be avoided unless the patient has a contraindication to anticoagulation. Many patients with symptomatic acute PE have persistent dyspnea and exercise limitations that often warrant further testing to rule out chronic thromboembolic pulmonary hypertension or chronic thromboembolic disease.
A 71-Year-Old Man With Dyspnea and Hypoxemia
Authors: Stroh Gregory R. , DuBrock Hilary M.
Published: February 2024

Hypoxemia is a common clinical issue that occasionally presents a diagnostic challenge to clinicians. An understanding of the underlying mechanisms of hypoxemia is essential to appropriately and effectively evaluate patients. When a patient has a rare underlying disease, an understanding of the mechanism of hypoxemia can assist with the diagnostic approach.
A 91-Year-Old Man With a Pulmonary Nodule, Abdominal Pain, and Anorexia
Authors: Azevedo Gross Luiza , de Moraes Alice Gallo
Published: February 2024

Asbestosis is an interstitial lung disease that is associated with an increased risk of malignancy. That risk is even higher if patients smoke tobacco. There are no lung cancer screening recommendations for patients who have asbestosis. However, the suspicion for malignancy should be low. Patients with asbestosis and an incidental lung nodule are definitely at high risk, and a nodule larger than 8 mm warrants follow-up computed tomography at 3 to 6 months.
On the cusp of cusps: a universal model for extreme scattering events in the ISM
Authors: Jow Dylan L , Pen Ue-Li , Baker Daniel
Published: February 2024

The scattering structures in the interstellar medium responsible for so-called extreme scattering events (ESEs), observed in quasars and pulsars, remain enigmatic. Current models struggle to explain the high-frequency light curves of ESEs, and a recent analysis of a double lensing event in PSR B0834+06 reveals features of ESEs that may also be challenging to accommodate via existing models. We propose that these features arise naturally when the lens has a cusp-like profile, described by the elementary A3 cusp catastrophe. This is an extension of previous work describing pulsar scintillation as arising from A2 fold catastrophes in thin, corrugated plasma sheets along the line of sight. We call this framework of describing the lens potentials via elementary catastrophes ‘doubly catastrophic lensing’, as catastrophes (e.g. folds and cusps) have long been used to describe universal features in the light curves of lensing events that generically manifest, regardless of the precise details of the lens. Here, we argue that the lenses themselves may be described by these same elementary structures. If correct, the doubly catastrophic lensing framework would provide a unified description of scintillation and ESEs, where the lenses responsible for these scattering phenomena are universal and can be fully described by a small number of unfolding parameters. This could enable their application as giant cosmic lenses for precision measurements of coherent sources, including fast radio bursts and pulsars.
Structure, kinematics, and time evolution of the Galactic warp from Classical Cepheids
Authors: Cabrera-Gadea Mauro , Mateu Cecilia , Ramos Pau , Romero-Gómez Mercé , Antoja Teresa , Aguilar Luis
Published: February 2024

The warp is a well-known undulation of the Milky Way disc. Its structure has been widely studied, but only since Gaia DR2 has it been possible to reveal its kinematic signature beyond the solar neighbourhood. In this work, we present an analysis of the warp traced by Classical Cepheids by means of a Fourier decomposition of their height (Z) and, for the first time, of their vertical velocity (Vz). We find a clear but complex signal that in both variables reveals an asymmetrical warp. In Z, we find the warp to be almost symmetric in amplitude at the disc’s outskirts, with the two extremes never being diametrically opposed at any radius and the line of nodes presenting a twist in the direction of stellar rotation for R > 11 kpc. For Vz, in addition to the usual m = 1 mode, an m = 2 mode is needed to represent the kinematic signal of the warp, reflecting its azimuthal asymmetry. The line of maximum vertical velocity is similarly twisted as the line of nodes and trails behind by ≈25°. We develop a new formalism to derive the pattern speed and change in amplitude with time $\dot{A}$ of each Fourier mode at each radius, via a joint analysis of the Fourier decomposition in Z and Vz. By applying it to the Cepheids we find, for the m = 1 mode, a constant pattern speed in the direction of stellar rotation of 9.2 ± 3.1 km s−1 kpc−1, a negligible $\dot{A}$ up to R ≈ 14 kpc and a slight increase at larger radii, in agreement with previous works.
Study of star formation in dual nuclei galaxies using UVIT observations
Authors: Rubinur K , Das M , Kharb P , Yadav J , Mondal C , Rahna P T
Published: February 2024

We have used the Ultraviolet Imaging Telescope (UVIT) aboard AstroSat to study star formation in a sample of nine dual nuclei galaxies with separations ⪅ 11 kpc, which is an expected outcome of galaxy mergers. To minimize the contribution of active galactic nuclei (AGN) emission, we have used mid-IR colour cut-offs and masked the AGN-dominated nuclei. The UV continuum slope (β) is used to calculate the internal extinction (AV) which ranges from 0.53 to 4.04 in the FUV band and 0.44 to 3.10 in the NUV band for the sample. We have detected 1−20 star-forming clumps in our sample galaxies. The extinction-corrected total FUV star formation rate (SFR) ranges from ∼0.35 to ∼32 M⊙ yr−1. Our analyses of AV, specific SFR (sSFR) show that dual nuclei sources are associated with dusty, star-forming galaxies. The FUV − NUV colour maps show redder colour in the nuclear and disc regions while bluer colour is observed in the outskirts of most galaxies which can be due to embedded dust or different stellar populations. We have found some signatures of possible stellar/AGN feedback like a ring of star formation, a redder ring around blue nuclei, etc. However, further observations are required to confirm this.
Extracellular G-quadruplexes and Z-DNA protect biofilms from DNase I, and G-quadruplexes form a DNAzyme with peroxidase activity
Authors: Minero Gabriel Antonio Salvador , Møllebjerg Andreas , Thiesen Celine , Johansen Mikkel Illemann , Jørgensen Nis Pedersen , Birkedal Victoria , Otzen Daniel Erik , Meyer Rikke Louise
Published: February 2024

Many bacteria form biofilms to protect themselves from predators or stressful environmental conditions. In the biofilm, bacteria are embedded in a protective extracellular matrix composed of polysaccharides, proteins and extracellular DNA (eDNA). eDNA most often is released from lysed bacteria or host mammalian cells, and it is the only matrix component most biofilms appear to have in common. However, little is known about the form DNA takes in the extracellular space, and how different non-canonical DNA structures such as Z-DNA or G-quadruplexes might contribute to its function in the biofilm. The aim of this study was to determine if non-canonical DNA structures form in eDNA-rich staphylococcal biofilms, and if these structures protect the biofilm from degradation by nucleases. We grew Staphylococcus epidermidis biofilms in laboratory media supplemented with hemin and NaCl to stabilize secondary DNA structures and visualized their location by immunolabelling and fluorescence microscopy. We furthermore visualized the macroscopic biofilm structure by optical coherence tomography. We developed assays to quantify degradation of Z-DNA and G-quadruplex DNA oligos by different nucleases, and subsequently investigated how these enzymes affected eDNA in the biofilms.

Z-DNA and G-quadruplex DNA were abundant in the biofilm matrix, and were often present in a web-like structures. In vitro, the structures did not form in the absence of NaCl or mechanical shaking during biofilm growth, or in bacterial strains deficient in eDNA or exopolysaccharide production. We thus infer that eDNA and polysaccharides interact, leading to non-canonical DNA structures under mechanical stress when stabilized by salt. We also confirmed that G-quadruplex DNA and Z-DNA was present in biofilms from infected implants in a murine implant-associated osteomyelitis model. Mammalian DNase I lacked activity against Z-DNA and G-quadruplex DNA, while Micrococcal nuclease could degrade G-quadruplex DNA and S1 Aspergillus nuclease could degrade Z-DNA. Micrococcal nuclease, which originates from Staphylococcus aureus, may thus be key for dispersal of biofilm in staphylococci. In addition to its structural role, we show for the first time that the eDNA in biofilms forms a DNAzyme with peroxidase-like activity in the presence of hemin. While peroxidases are part of host defenses against pathogens, we now show that biofilms can possess intrinsic peroxidase activity in the extracellular matrix.