Medical Student Cheater: January 2011

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Saturday, January 15, 2011

Folliculitis

Folliculitis is defined histologically as the presence of inflammatory cells within the wall and ostia of the hair follicle, creating a follicular-based pustule. The actual type of inflammatory cells can vary and may be dependent on the etiology of the folliculitis, the stage at which the biopsy specimen was obtained, or both. The inflammation can be either limited to the superficial aspect of the follicle with primary involvement of the infundibulum or the inflammation can affect both the superficial and deep aspect of the follicle. Deep folliculitis can eventuate from chronic lesions of superficial folliculitis or from lesions that are manipulated, and this may ultimately result in scarring.

Perifolliculitis, on the other hand, is defined as the presence of inflammatory cells in the perifollicular tissues and can involve the adjacent reticular dermis. Folliculitis and perifolliculitis can manifest independently or together as a result of follicular disruption and irritation.

Acne represents a noninfectious form of folliculitis. The follicular inflammation seen in acne occurs as a secondary event as a result of follicular obstruction from abnormal keratinization. In acne, the superficial aspect of the follicle distends and is obstructed by a keratin plug. The sebum fills the follicle, and the normally commensal bacteria (Propionibacterium acnes) produces excess free fatty acids, which trigger follicular inflammation.

Esophagitis

The most common cause of esophagitis is gastroesophageal reflux disease (GERD). Other important, but less common, causes are infections, medications, radiation therapy, systemic disease, and trauma. Eosinophilic esophagitis has emerged as an important cause of esophagitis in both children and adults.


Diarrhea

Acute diarrhea is defined as the abrupt onset of abnormally high fluid content in the stool: more than the normal value of approximately 10 mL/kg/d in the infant and young child, and more than 200 g/d in the teenager and adult. This situation typically implies an increased frequency of bowel movements, which can range from 4-5 to more than 20 times per day. The augmented water content in the stools is due to an imbalance in the physiology of the small and large intestinal processes involved in the absorption of ions, organic substrates, and thus water. A common disorder in its acute form, diarrhea has many causes and may be mild to severe.

Childhood acute diarrhea is usually caused by infection; however, numerous disorders may cause this condition, including a malabsorption syndrome and various enteropathies. Acute-onset diarrhea is usually self-limited; however, an acute infection can have a protracted course. By far, the most common complication of acute diarrhea is dehydration.
Although the term "acute gastroenteritis" is commonly used synonymously with "acute diarrhea," the former term is a misnomer. The term gastroenteritis implies inflammation of both the stomach and the small intestine, whereas, in reality, gastric involvement is rarely if ever seen in acute diarrhea (including diarrhea with an infectious origin); enteritis is also not consistently present. Examples of infectious acute diarrhea syndromes that do not cause enteritis include Vibrio cholerae– induced diarrhea and Shigella -induced diarrhea. Thus, the term acute diarrhea is preferable to acute gastroenteritis.
Diarrheal episodes are classically distinguished into acute and chronic (or persistent) based on their duration. Acute diarrhea is thus defined as an episode that has an acute onset and lasts no longer than 14 days; chronic or persistent diarrhea is defined as an episode that lasts longer than 14 days. The distinction, supported by the World Health Organization (WHO), has implications not only for classification and epidemiological studies but also from a practical standpoint because protracted diarrhea often has a different set of causes, poses different problems of management, and has a different prognosis.

Dengue Fever

Dengue, the most common arboviral illness transmitted worldwide, is caused by infection with 1 of the 4 serotypes of dengue virus, family Flaviviridae, genus Flavivirus (single-stranded nonsegmented RNA viruses). Dengue is transmitted by mosquitoes of the genus Aedes,which are widely distributed in subtropical and tropical areas of the world, and is classified as a major global health threat by the World Health Organization (WHO).
Initial dengue infection may be asymptomatic (50%-90%), may result in a nonspecific febrile illness, or may produce the symptom complex of classic dengue fever (DF). A small percentage of persons who have previously been infected by one dengue serotype develop bleeding and endothelial leak upon infection with another dengue serotype. This syndrome is termed dengue hemorrhagic fever (DHF), although dengue vasculopathy has been proposed as a better term, as fluid loss into tissue spaces can lead to prolonged shock and complications, including gastrointestinal bleeding, a greater fatality risk than bleeding per se. Some patients with dengue hemorrhagic fever develop shock (dengue shock syndrome [DSS]), which may cause death.
Dengue fever–like illnesses were described in Chinese medical writings dating back to 265 AD. Outbreaks of febrile illnesses compatible with dengue fever have been recorded throughout history, with the first epidemic described in 1635 in the West Indies. In 1789, Benjamin Rush, MD, published an account of a probable dengue fever epidemic that had occurred in Philadelphia in 1780. Rush coined the term breakbone fever to describe the intense symptoms reported by one of his patients. Probable outbreaks of dengue fever occurred sporadically every 10-30 years until after World War II. The socioeconomic disruptions caused by World War II resulted in increased worldwide spread of dengue viruses.
The first epidemic of dengue hemorrhagic fever was described in Manila in 1953. After that, outbreaks of dengue fever became more common. A pattern developed in which dengue fever epidemics occurred with increasing frequency and were associated with occasional dengue hemorrhagic fever cases. Subsequently, dengue hemorrhagic fever epidemics occurred every few years. Eventually, dengue hemorrhagic fever epidemics occurred yearly, with major outbreaks occurring approximately every 3 years. This pattern has repeated itself as dengue fever has spread to new regions.
Although initial epidemics were located in urban areas, increased dengue spread has involved suburban and rural locales in Asia and Latin America. The only continents that do not experience dengue transmission include Europe and Antarctica. In the 1950s, 9 countries reported dengue outbreaks; today, the geographic distribution includes more than 100 countries worldwide. Several of these countries had not previously reported dengue, and many had not reported dengue in 20 years.
Dengue transmission spread from Southeast Asia into surrounding subtropical and tropical Asian countries, southern China and southern Taiwan, the Indian subcontinent and Sri Lanka, and down the island nations of Malaysia, the Philippines, New Guinea, northeastern Australia, and several Pacific islands, including Tahiti, Palau, Tonga, and the Cook Islands. Nepal has not reported dengue transmission. Hyperendemic transmission is reported in Vietnam, Thailand, Indonesia, Pakistan, India, Malaysia, and the Philippines. Dengue continues to extend its range.
Currently, dengue hemorrhagic fever is one of the leading causes of hospitalization and death in children in many Southeast Asian countries, with Indonesia reporting the majority of dengue hemorrhagic fever cases. Of interest and significance in prevention and control, 3 surveillance studies in Asia report an increasing age among infected patients and increasing mortality rate. Since 1982 in Singapore, more than 50% of deaths have occurred in individuals older than 15 years. In Indonesia, young adults in Jakarta and provincial areas make up a larger percentage of infected patients. During the 2000 epidemic in Bangladesh, up to 82% of hospitalized patients were adults, and all deaths occurred in patients older than 5 years.

The Last Hours of Living: Practical Advice for Clinicians

Clinical competence, willingness to educate, and calm and empathic reassurance are critical to helping patients and families during a loved one's last hours of living. Clinical issues that commonly arise in the last hours of living include the management of feeding and hydration, changes in consciousness, delirium, pain, breathlessness, and secretions. Management principles are the same whether the patient is at home or in a healthcare institution. However, death in an institution requires accommodations that may not be customary to assure privacy, cultural observances, and communication. In anticipation of the event, inform the family and other professionals about what to do and what to expect. Care does not end until the family has been supported with their grief reactions and those with complicated grief have been helped to get care.

Coronary Artery Atherosclerosis

Coronary artery atherosclerosis is the principal cause of coronary artery disease (CAD) and is the single largest killer of both men and women in the United States.

Approximately 14 million Americans have CAD. Each year, 1.5 million individuals develop acute myocardial infarction (AMI), the most deadly presentation of CAD, and more than 500,000 of these individuals die. Survivors of myocardial infarction (MI) continue to have a poor prognosis, and their risk of mortality and morbidity is 1.5-15 times greater than that of the rest of the population. This fact remains true despite a 30% reduction in mortality from CAD over the past 3 decades. Many factors have led to a decrease in mortality and morbidity from AMI, including the introduction of coronary care units, coronary artery bypass grafting, thrombolytic therapy, percutaneous coronary intervention (eg, percutaneous transluminal coronary angioplasty [PTCA]), and a renewed emphasis on lifestyle modification.