The carotid body and associated tumors: updated review with clinical/surgical significance.

Purpose: The carotid body functions as a chemoreceptor and receives richer blood supply, by weight, than any other organ in the body. We review the literature regarding the anatomy, histology, and function of the carotid body and the incidence, functionality, and clinical relevance of carotid body tumors and paragangliomas. These lesions are often nonfunctional but can be associated with catecholamine secretion. Most patients are asymptomatic or present initially with a cervical mass. As the tumors grow, they can impinge on nearby cranial nerves. Although there is some debate, the dominant clinical strategy is to surgically resect these tumors as early as possible. If they are resected early, the risk of postoperative neurovascular injury is minimized. Methods: Literature search was performed using the PubMed database with focus on articles including descriptions of the carotid body and associated tumors. Results: We reviewed recent literature that related to the anatomy of the carotid body while also including carotid pargangliomas and associated diagnosis with treatment interventions. Conclusion: As the carotid body serves as a vital modulator of cardiovascular and respiratory functions, illustrates the importance of identifying potential carotid paragangliomas due its ability to impede function of the carotid body. By understanding carotid paraganglioma's distinct etiologies while also understanding proper diagnosis of tumors allows for early detection and appropriate treatment options.

Prolonged cardiac arrest complicating a massive ST-segment elevation myocardial infarction associated with marijuana consumption.

Recreational substance use and misuse constitute a major public health issue. The annual rate of recreational drug overdose-related deaths is increasing exponentially, making unintentional overdose as the leading cause of injury-related deaths in the United States. Marijuana is the most widely used recreational illicit drug, with approximately 200 million users worldwide. Although it is generally regarded as having low acute toxicity, heavy marijuana usage has been associated with life-threatening consequences. Marijuana is increasingly becoming legal in the United States for both medical and recreational use. Although the most commonly seen adverse effects resulting from its consumption are typically associated with neurobehavioral and gastrointestinal symptoms, cases of severe toxicity involving the cardiovascular system have been reported. In this report, the authors describe a case of cannabis-associated ST-segment elevation myocardial infarction leading to a prolonged cardiac arrest.

Disseminated Cryptococcal Infection Resulting in Acute Respiratory Distress Syndrome (ARDS) as the Initial Clinical Presentation of AIDS.

Cryptococcosis is a cosmopolitan but rare opportunistic mycosis which is usually caused by Cryptococcus neoformans. Although the most common and worrisome disease manifestation is meningoencephalitis, pulmonary cryptococcosis has the potential to be lethal. The diagnosis of cryptococcal pneumonia is challenging, given its non-specific clinical and radiographic features. Respiratory failure leading to acute respiratory distress syndrome as a consequence of cryptococcal disease has been infrequently addressed in the literature. We herein present a case of disseminated cryptococcal infection leading to acute respiratory distress syndrome, refractory shock, and multiorgan dysfunction as the initial clinical manifestation in a patient who was newly diagnosed with acquired immunodeficiency syndrome.

Assessing the utility of ICU admission for octogenarians.

BACKGROUND: Advanced age is associated with increased severity of acute critical illnesses and admission to ICU. Despite advances in the support for older critically ill patients, the short- and long-term mortality rates remain substantial. The purpose of this study is to analyze the factors influencing the outcome of a geriatric population admitted to the ICU. METHODS: A single-center, prospective, observational study was conducted among all geriatric patients, 80 years or older, admitted to ICU during a 6-month study period. RESULTS: Fifty-two patients were admitted. Mean age was 85.1 years (range 80-96), mean APACHE-II score was 24.7 (range 11-40), and mean frailty score was 5.8 (range 3-8). Thirty-nine (75 %) patients received mechanical ventilation, and 31 (59.7 %) were on vasoactive therapy. Twenty-four (46.3 %) patients died during their hospital admission, and 13 (25 %) of them expired in ICU. DISCUSSION: Advanced age, needs for vasopressor therapy, and mechanical ventilation are independent predictive factors of adverse outcome. Pre-admission functional status was not independently associated with unfavorable outcome.

Massive cerebral edema resulting in brain death as a complication of Cryptococcus neoformans meningitis.

Despite the widespread use of highly active antiretroviral therapy, cryptococcal meningoencephalitis has emerged as the second leading cause of infectious morbidity and mortality in HIV-infected patients worldwide. It presents usually as subacute or chronic disease but occasionally may be fulminant. Common clinical presentations included headache, fever, and depressed level of consciousness. The infection affects both the subarachnoid space and brain parenchyma, and is characterized by a paucity of inflammation and a large fungal burden in the cerebrospinal fluid at the time of diagnosis. Infection is usually lethal without treatment, thus the prompt diagnosis and therapy might improve the outcome. We report a case of brain death caused by Cryptococcus neoformans meningitis that was diagnosed based on clinical neurological examinations and supported by the absence of cerebral blood flow on brain angiography.

The Wide and Unpredictable Scope of Synthetic Cannabinoids Toxicity.

Drug use and abuse continue to be a large public health concern worldwide. Over the past decade, novel or atypical drugs have emerged and become increasingly popular. In the recent past, compounds similar to tetrahydrocannabinoid (THC), the active ingredient of marijuana, have been synthetically produced and offered commercially as legal substances. Since the initial communications of their abuse in 2008, few case reports have been published illustrating the misuse of these substances with signs and symptoms of intoxication. Even though synthetic cannabinoids have been restricted, they are still readily available across USA and their use has been dramatically increasing, with a concomitant increment in reports to poison control centers and emergency department (ED) visits. We describe a case of acute hypoxemic/hypercapnic respiratory failure as a consequence of acute congestive heart failure (CHF) developed from myocardial stunning resulting from a non-ST-segment elevation myocardial infarction (MI) following the consumption of synthetic cannabinoids.

Humphrey Ridley (1653-1708): forgotten neuroanatomist and neurophysiologist.

Humphrey Ridley is a little known character in the history of anatomy and physiology. Born in 1653, Ridley was a physician and anatomist who followed the research done by Willis, Vieussens, and Galen. Outside of a cursory knowledge of his birth and death, readers have only two remnants of his contributions to science: The Anatomy of the Brain, containing its Mechanism and Physiology and Observationes Quaedam Medico-Practicae et Physiologicae de Asthmate et Hydrophobia. The former text was the first book in the English language written on the human brain. Ridley's studies using cadavers executed by hanging provided him with a novel view of the venous drainage and lymphatic system not seen as accurately by those before him. Since the study of the brain was still largely in its infancy, he was not without his errors of deduction as to the purpose of parts of the brain and its pathologies. With his dissections, however, Ridley was able to build on the collective knowledge of neuroanatomy and provided new insight into brain structure and function. The current paper reviews what is known of Ridley's life and contributions to neuroanatomy and neurophysiology.

Prognostic factors associated with adverse outcome among critically ill elderly patients admitted to the intensive care unit.

INTRODUCTION: Despite concerns over the appropriateness and quality of care provided in the intensive care unit (ICU) at the end of life, the number of elderly patients who receive critical care is increasing. Despite this, many physicians have doubts as to whether elderly patients are good candidates for ICU care because of the apparently poor outcome during and after critical care in this population. The objective of the present study was to describe the clinical characteristics and outcome of a geriatric population admitted to the ICU. MATERIALS AND METHODS: A single-center, prospective, observational study was carried out among geriatric patients, aged 75 years or older, admitted to ICU. RESULTS: A total of 71 patients were admitted to ICU during the study period. Their mean age was 83 years (range 75-98 years), with a mean Acute Physiology and Chronic Health Evaluation-II score of 21.8 (range 8-39) on admission to ICU. A total of 48 patients (68%) required mechanical ventilation, and 39 (55%) received at least one vasoactive drug. The mean ICU length of stay was 4.6 days (range 1-18 days), and it was similar for ICU survivors and non-survivors (4.7 vs 4.5). A total of 14 patients (19.7%) were admitted after cardiac arrest, and eight (57.1%) of them died in ICU. A total of 28 patients (39.4%) died in the hospital, and 18 (25.4%) died in ICU. CONCLUSION: Advanced age, critical illness, cardiopulmonary resuscitation, and needs for mechanical ventilation and/or vasopressor therapy are independent risk factors associated with adverse outcome in elderly patients admitted to ICU. Alternatives for ICU admission should be considered in geriatric patients with severe critical illnesses.

Triage of Patients Consulted for ICU Admission During Times of ICU-Bed Shortage.

BACKGROUND: The demand for specialized medical services such as critical care often exceeds availability, thus rationing of intensive care unit (ICU) beds commonly leads to difficult triage decisions. Many factors can play a role in the decision to admit a patient to the ICU, including severity of illness and the need for specific treatments limited to these units. Although triage decisions would be based solely on patient and institutional level factors, it is likely that intensivists make different decisions when there are fewer ICU beds available. The objective of this study is to evaluate the characteristics of patients referred for ICU admission during times of limited beds availability. METHODS: A single center, prospective, observational study was conducted among consecutive patients in whom an evaluation for ICU admission was requested during times of ICU overcrowding, which comprised the months of April and May 2014. RESULTS: A total of 95 patients were evaluated for possible ICU admission during the study period. Their mean APACHE-II score was 16.8 (median 16, range 3 - 36). Sixty-four patients (67.4%) were accepted to ICU, 18 patients (18.9%) were triaged to SDU, and 13 patients (13.7%) were admitted to hospital wards. ICU had no beds available 24 times (39.3%) during the study period, and in 39 opportunities (63.9%) only one bed was available. Twenty-four patients (25.3%) were evaluated when there were no available beds, and eight of those patients (33%) were admitted to ICU. A total of 17 patients (17.9%) died in the hospital, and 15 (23.4%) expired in ICU. CONCLUSION: ICU beds are a scarce resource for which demand periodically exceeds supply, raising concerns about mechanisms for resource allocation during times of limited beds availability. At our institution, triage decisions were not related to the number of available beds in ICU, age, or gender. A linear correlation was observed between severity of illness, expressed by APACHE-II scores, and the likelihood of being admitted to ICU. Alternative locations outside the ICU in which care for critically ill patients could be delivered should be considered during times of extreme ICU-bed shortage.

Amyand's hernia: a review.

Abstract Amyand's hernia is defined as when the appendix is trapped within an inguinal hernia. While the incidence of this type of hernia is rare, the appendix may become incarcerated within Amyand's hernia and lead to further complications such as strangulation and perforation. Incarceration of the appendix most commonly occurs within inguinal and femoral hernias, but may arise to a lesser extent in incisional and umbilical hernias. Incarcerated appendix has been reported in a variety of ventral abdominal and inguinal locations, yet its indistinct clinical presentation represents a diagnostic challenge. This paper reviews the literature on incarceration of the appendix within inguinal hernias and discusses current approaches to diagnosis and treatment of Amyand's hernia and complications that may arise from incarceration of the appendix within the hernia.

The anatomy of the aortic root.

The aortic root is the anatomical bridge between the left ventricle and the ascending aorta. It is made up of the aortic valve leaflets, which are supported by the aortic sinuses (of Valsalva), and the interleaflet triangles interposed between the basal attachments of the leaflets. As such, it possesses significant length, and because of the semilunar attachment of the leaflets, there is no discrete proximal border to the root. It is limited distally, nonetheless, by the supravalvar ridge, or sinutubular junction. Descriptions of the aortic root over the years have been bedeviled by accounts of a valve anulus. There are at least two rings within the root, but neither serves to support the valve leaflets, each leaflets being attached in semilunar fashion from the sinutubular junction to a basal ventricular attachment Two leaflets are supported by muscle, and the third has an exclusively fibrous attachment. The root acts as a bridging structure not only anatomically, separating the myocardial and arterial components of the left ventricular pathway, but also functionally, since its proximal and distal components can withstand considerable changes in ventricular and arterial pressures. In this review, we describe the anatomy of this crucial cardiac component, emphasizing the current problems which have arisen due to indiscriminate descriptions of a nonexistent anulus.

Pneumomediastinum and the aortic nipple: the clinical relevance of the left superior intercostal vein.

This article discusses the appearance of the "aortic nipple" in chest radiography, and reviews the embryology and anatomy of the left superior intercostal vein which causes the appearance of an "aortic nipple." This radiological sign is useful in differentiating certain thoracic pathologies, such as pneumomediastinum, pneumopericardium, and medial pneumothorax. Pneumomediastinum is an encompassing term describing the presence of air in the mediastinum, and may arise from a wide range of pathological conditions. Despite the well-described imaging of pneumomediastinum, it is sometimes difficult to differentiate from other conditions such as pneumopericardium and medial pneumothorax. A separate finding, "aortic nipple" is the radiographic term used to describe the lateral nipple-like projection from the aortic knob present in a small number of individuals. The aortic nipple corresponds to the end-on appearance of the left superior intercostal vein coursing around the aortic knob, and may be mistaken radiologically for lymphadenopathy or a neoplasm. Despite their relative independence, the aortic nipple is defined by new contours in cases of pneumomediastinum, taking on an "inverted aortic nipple" appearance. In this position, the inverted aortic nipple may facilitate radiographic discrimination of pneumomediastinum from similar conditions. This study aims to review the common clinical and radiographic features of both pneumomediastinum and the aortic nipple. The radiologic appearance of the aortic nipple occurring in unison with pneumomediastinum, and its potential role as a tool in the differentiation of pneumomediastinum from similarly presenting conditions will also be described.

Double-chambered right ventricle: a review.

A double-chambered right ventricle is a rare heart defect in which the right ventricle is separated into a high-pressure proximal and low-pressure distal chamber. This defect is considered to be congenital and typically presents in infancy or childhood but has been reported to present rarely in adults. It can be caused by the presence of anomalous muscle tissue, hypertrophy of the endogenous trabecular bands, or an aberrant moderator band; all of which will typically result in progressive obstruction of the outflow tract. In this paper, we will discuss the general anatomy of the right ventricle, the relevant embryology of the heart, and the presentation, diagnosis, and treatment of a double-chambered right ventricle.

The clinical anatomy of the coronary arteries.

There are a manifold number of variations and anomalies of the origin and course of coronary arteries described in the literature. The incidence of such variations in the general population is reported to range between 0.3 and 1.6 %. Although uncommon, they may be benign or produce symptoms ranging from mild dyspnea to sudden cardiac death, and have been associated with an increased risk of accelerated atherosclerosis and perfusion defects. Thus, in order to effectively utilize the increasing number of therapeutic options available for treating coronary artery diseases, an appreciation of the likely normal and variable arrangements of the coronary arteries is essential. This review will describe the normal anatomy of the coronary arteries as well as the common variations with potential clinical effects.