Hypertension

Hypertension
Hypertension is the term used to describe high blood pressure.
Blood pressure readings are measured in millimeters of mercury (mmHg) and usually given as two numbers. For example, 120 over 80 (written as 120/80 mmHg).
• The top number is your systolic pressure, the pressure created when your heart beats. It is considered high if it is consistently over 140.
• The bottom number is your diastolic pressure, the pressure inside blood vessels when the heart is at rest. It is considered high if it is consistently over 90.
Either or both of these numbers may be too high.
Pre-hypertension is when your systolic blood pressure is between 120 and 139 or your diastolic blood pressure is between 80 and 89 on multiple readings. If you have pre-hypertension, you are more likely to develop high blood pressure.
See also: Blood pressure
Causes
Blood pressure measurements are the result of the force of the blood produced by the heart and the size and condition of the arteries.
Many factors can affect blood pressure, including:
• How much water and salt you have in your body
• The condition of your kidneys, nervous system, or blood vessels
• The levels of different body hormones
High blood pressure can affect all types of people. You have a higher risk of high blood pressure if you have a family history of the disease. High blood pressure is more common in African Americans than Caucasians. Smoking, obesity, and diabetes are all risk factors for hypertension.
Most of the time, no cause is identified. This is called essential hypertension.
High blood pressure that results from a specific condition, habit, or medication is called secondary hypertension. Too much salt in your diet can lead to high blood pressure. Secondary hypertension may also be due to:
• Adrenal gland tumor
• Alcohol abuse
• Anxiety and stress
• Arteriosclerosis
• Birth control pills
• Coarctation of the aorta
• Cocaine use
• Cushing syndrome
• Diabetes
• Kidney disease, including:
o Glomerulonephritis (inflammation of kidneys)
o Kidney failure
o Renal artery stenosis
o Renal vascular obstruction or narrowing
• Medications
o Appetite suppressants
o Certain cold medications
o Corticosteroids
o Migraine medications
• Hemolytic-uremic syndrome
• Henoch-Schonlein purpura
• Obesity
• Pain
• Periarteritis nodosa
• Pheochromocytoma
• Pregnancy (called gestational hypertension)
• Primary hyperaldosteronism
• Renal artery stenosis
• Retroperitoneal fibrosis
• Wilms' tumor
Symptoms
Most of the time, there are no symptoms. Symptoms that may occur include:
• Chest pain
• Confusion
• Ear noise or buzzing
• Irregular heartbeat
• Nosebleed
• Tiredness
• Vision changes
If you have a severe headache or any of the symptoms above, see your doctor right away. These may be signs of a complication or dangerously high blood pressure called malignant hypertension.


Exams and Tests
Your health care provider will perform a physical exam and check your blood pressure. If the measurement is high, your doctor may think you have high blood pressure. The measurements need to be repeated over time, so that the diagnosis can be confirmed.
If you monitor your blood pressure at home, you may be asked the following questions:
• What was your most recent blood pressure reading?
• What was the previous blood pressure reading?
• What is the average systolic (top number) and diastolic (bottom number) reading?
• Has your blood pressure increased recently?
Other tests may be done to look for blood in the urine or heart failure. Your doctor will look for signs of complications to your heart, kidneys, eyes, and other organs in your body.
These tests may include:
• Chem-20
• Echocardiogram
• Urinalysis
• Ultrasound of the kidneys
Treatment
The goal of treatment is to reduce blood pressure so that you have a lower risk of complications.
There are many different medicines that can be used to treat high blood pressure, including:
• Alpha blockers
• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin receptor blockers (ARBs)
• Beta-blockers
• Calcium channel blockers
• Central alpha agonists
• Diuretics
• Renin inhibitors, including aliskiren (Tekturna)
• Vasodilators
Your doctor may also tell you to exercise, lose weight, and follow a healthier diet. If you have pre-hypertension, your doctor will recommend the same lifestyle changes to bring your blood pressure down to a normal range.
Often, a single blood pressure drug may not be enough to control your blood pressure, and you may need to take two or more drugs. It is very important that you take the medications prescribed to you. If you have side effects, your health care provider can substitute a different medication.
Outlook (Prognosis)
Most of the time, high blood pressure can be controlled with medicine and lifestyle changes.
Possible Complications
• Aortic dissection
• Blood vessel damage (arteriosclerosis)
• Brain damage
• Congestive heart failure
• Kidney damage
• Kidney failure
• Heart attack
• Hypertensive heart disease
• Stroke
• Vision loss
When to Contact a Medical Professional
If you have high blood pressure, you will have regularly scheduled appointments with your doctor.
Even if you have not been diagnosed with high blood pressure, it is important to have your blood pressure checked during your yearly check-up, especially if someone in your family has or had high blood pressure.
Call your health care provider right away if home monitoring shows that your blood pressure remains high or you have any of the following symptoms:
• Chest pain
• Confusion
• Excessive tiredness
• Nausea and vomiting
• Severe headache
• Shortness of breath
• Significant sweating
• Vision changes
Prevention
Adults over 18 should have their blood pressure checked routinely.
Lifestyle changes may help control your blood pressure:
• Lose weight if you are overweight. Excess weight adds to strain on the heart. In some cases, weight loss may be the only treatment needed.
• Exercise regularly. If possible, exercise for 30 minutes on most days.
• Eat a diet rich in fruits, vegetables, and low-fat dairy products while reducing total and saturated fat intake (the DASH diet is one way of achieving this kind of dietary plan). (See: Heart disease and diet)
• Avoid smoking. (See: Nicotine withdrawal)
• If you have diabetes, keep your blood sugar under control.
• Do not consume more than 1 or 2 alcoholic drinks per day.
• Try to manage your stress.
Follow your health care provider's recommendations to modify, treat, or control possible causes of secondary hypertension.

What is high blood pressure?
High blood pressure (HBP) or hypertension means high pressure (tension) in the arteries. Arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension", and a blood pressure of 140/90 or above is considered high.
The top number, the systolic blood pressure, corresponds to the pressure in the arteries as the heart contracts and pumps blood forward into the arteries. The bottom number, the diastolic pressure, represents the pressure in the arteries as the heart relaxes after the contraction. The diastolic pressure reflects the lowest pressure to which the arteries are exposed.
An elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease, kidney (renal) disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke (brain damage). These complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. For that reason, the diagnosis of high blood pressure is important so efforts can be made to normalize blood pressure and prevent complications.
It was previously thought that rises in diastolic blood pressure were a more important risk factor than systolic elevations, but it is now known that in people 50 years or older systolic hypertension represents a greater risk.




INFLUENZA
What is influenza?
Influenza, commonly called "the flu," is an illness caused by RNA viruses that infect the respiratory tract of many animals, birds, and humans. In most people, the infection results in the person getting fever, cough, headache, and malaise (tired, no energy); some people also may develop a sore throat, nausea, vomiting, and diarrhea. The majority of individuals has symptoms for about one to two weeks and then recovers with no problems. However, compared with most other viral respiratory infections, such as the common cold, influenza (flu) infection can cause a more severe illness with a mortality rate (death rate) of about 0.1% of people who are infected with the virus.
The above is the usual situation for the yearly occurring "conventional" or "seasonal" flu strains. However, there are situations in which some flu outbreaks are severe. These severe outbreaks occur when the human population is exposed to a flu strain against which the population has little or no immunity because the virus has become altered in a significant way. Unusually severe worldwide outbreaks (pandemics) have occurred several times in the last hundred years since influenza virus was identified in 1933. By an examination of preserved tissue, the worst influenza pandemic (also termed the Spanish flu) occurred in 1918 when the virus caused between 40-100 million deaths worldwide, with a mortality rate estimated to range from 2%-20%.
In April 2009, a new influenza strain against which the world population has little or no immunity was isolated from humans in Mexico. It quickly spread throughout the world so fast that the WHO declared this new flu strain (termed novel H1N1 influenza A swine flu, often shortened to H1N1 or swine flu) as the cause of a pandemic on June 11, 2009. This was the first declared flu pandemic in 41 years.
Haemophilus influenzae is a bacterium that was incorrectly considered to cause the flu until the virus was demonstrated to be the correct cause in 1933. This bacterium can cause lung infections in infants and children, and it occasionally causes ear, eye, sinus, joint, and a few other infections, but it does not cause the flu.
What are the causes of the flu?
The flu (influenza) viruses

Influenza viruses cause the flu and are divided into three types, designated A, B, and C. Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter and are often associated with increased rates of hospitalization and death. Influenza type C differs from types A and B in some important ways. Type C infection usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public-health impact of influenza types A and B. Efforts to control the impact of influenza are aimed at types A and B, and the remainder of this discussion will be devoted only to these two types.
Influenza viruses continually change over time, usually by mutation (change in the viral RNA). This constant changing often enables the virus to evade the immune system of the host (humans, birds, and other animals) so that the host is susceptible to changing influenza virus infections throughout life. This process works as follows: a host infected with influenza virus develops antibodies against that virus; as the virus changes, the "first" antibody no longer recognizes the "newer" virus and infection can occur because the host does not recognize the new flu virus as a problem until the infection is well under way. The first antibody developed may, in some instances, provide partial protection against infection with a new influenza virus. Unfortunately, almost all individuals have no antibodies that will recognize the novel H1N1 virus immediately. Consequently, without vaccination, the majority of the human population is susceptible to novel H1N1 flu.
Type A viruses are divided into types based on differences in two viral surface proteins called the hemagglutinin (H) and the neuraminidase (N). There are 16 known H subtypes and nine known N subtypes. These surface proteins can occur in many combinations. When spread by droplets or direct contact, the virus, if not killed by the host's immune system, replicates in the respiratory tract and damages host cells. In people who are immune compromised (for example, pregnant individuals, infants, cancer patients, asthma patients, people with pulmonary disease and many others), the virus can cause viral pneumonia or stress the individual's system to make them more susceptible to bacterial infections, especially bacterial pneumonia. Both pneumonia types, viral and bacterial, can cause severe disease and sometimes death.

Antigenic shift and drift
Influenza type A viruses undergo two kinds of changes. One is a series of mutations that occurs over time and causes a gradual evolution of the virus. This is called antigenic "drift." The other kind of change is an abrupt change in the hemagglutinin and/or the neuraminidase proteins. This is called antigenic "shift." In this case, a new subtype of the virus suddenly emerges. Type A viruses undergo both kinds of changes; influenza type B viruses change only by the more gradual process of antigenic drift and therefore do not cause pandemics.
A diagram that illustrates both antigenic shift and drift can be found at http://www.medicinenet.com/swine_flu/page5.htm and shows how both mechanisms can lead to antigenically diverse virus strains. The U.S. Centers for Disease Control and Prevention (CDC) has indicated that novel H1N1 swine flu has an RNA genome that contains five RNA strands derived from various swine flu strains, two RNA strands from bird flu strains, and only one RNA strand from human flu strains. They suggest mainly antigenic shifts over about 20 years have led to the development of novel H1N1 flu virus


ABOUTE INFLUENZA

influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses), that affects birds and mammals. The most common symptoms of the disease are chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue and general discomfort.[1] Sore throat, fever and coughs are the most frequent symptoms. In more serious cases, influenza causes pneumonia, which can be fatal, particularly for the young and the elderly. Although it is often confused with other influenza-like illnesses, especially the common cold, influenza is a much more severe disease than the common cold and is caused by a different type of virus.[2] Influenza may produce nausea and vomiting, particularly in children,[1] but these symptoms are more common in the unrelated gastroenteritis, which is sometimes called "stomach flu" or "24-hour flu".[3]
Typically, influenza is transmitted through the air by coughs or sneezes, creating aerosols containing the virus. Influenza can also be transmitted by direct contact with bird droppings or nasal secretions, or through contact with contaminated surfaces. Airborne aerosols have been thought to cause most infections, although which means of transmission is most important is not absolutely clear.[4] Influenza viruses can be inactivated by sunlight, disinfectants and detergents.[5][6] As the virus can be inactivated by soap, frequent hand washing reduces the risk of infection.
Influenza spreads around the world in seasonal epidemics, resulting in the deaths of between 250,000 and 500,000 people every year,[7] and millions in pandemic years. On average 41,400 people died each year in the United States between 1979 and 2001 from influenza.[8] Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans. Often, these new strains appear when an existing flu virus spreads to humans from other animal species, or when an existing human strain picks up new genes from a virus that usually infects birds or pigs. An avian strain named H5N1 raised the concern of a new influenza pandemic, after it emerged in Asia in the 1990s, but it has not evolved to a form that spreads easily between people.[9] In April 2009 a novel flu strain evolved that combined genes from human, pig, and bird flu, initially dubbed "swine flu" and also known as influenza A/H1N1, emerged in Mexico, the United States, and several other nations. The World Health Organization officially declared the outbreak to be a pandemic on June 11, 2009 (see 2009 flu pandemic). The WHO's declaration of a pandemic level 6 was an indication of spread, not severity.[10]
Vaccinations against influenza are usually given to people in developed countries[11] and to farmed poultry.[12] The most common human vaccine is the trivalent influenza vaccine (TIV) that contains purified and inactivated material from three viral strains. Typically, this vaccine includes material from two influenza A virus subtypes and one influenza B virus strain.[13] The TIV carries no risk of transmitting the disease, and it has very low reactivity. A vaccine formulated for one year may be ineffective in the following year, since the influenza virus evolves rapidly, and new strains quickly replace the older ones. Antiviral drugs can be used to treat influenza, with neuraminidase inhibitors being particularly effective.

PNEUMONIA

What is pneumonia?
Pneumonia is an infection of one or both lungs which is usually caused by bacteria, viruses, or fungi. Prior to the discovery of antibiotics, one-third of all people who developed pneumonia subsequently died from the infection. Currently, over 3 million people develop pneumonia each year in the United States. Over a half a million of these people are admitted to a hospital for treatment. Although most of these people recover, approximately 5% will die from pneumonia. Pneumonia is the sixth leading cause of death in the United States.
How do people "catch pneumonia"?
Some cases of pneumonia are contracted by breathing in small droplets that contain the organisms that can cause pneumonia. These droplets get into the air when a person infected with these germs coughs or sneezes. In other cases, pneumonia is caused when bacteria or viruses that are normally present in the mouth, throat, or nose inadvertently enter the lung. During sleep, it is quite common for people to aspirate secretions from the mouth, throat, or nose. Normally, the body's reflex response (coughing back up the secretions) and immune system will prevent the aspirated organisms from causing pneumonia. However, if a person is in a weakened condition from another illness, a severe pneumonia can develop. People with recent viral infections, lung disease, heart disease, and swallowing problems, as well as alcoholics, drug users, and those who have suffered a stroke or seizure are at higher risk for developing pneumonia than the general population.
Once organisms enter the lungs, they usually settle in the air sacs of the lung where they rapidly grow in number. This area of the lung then becomes filled with fluid and pus as the body attempts to fight off the infection.
What are pneumonia symptoms and signs?
Most people who develop pneumonia initially have symptoms of a cold which are then followed by a high fever (sometimes as high as 104 degrees Fahrenheit), shaking chills, and a cough with sputum production. The sputum is usually discolored and sometimes bloody. People with pneumonia may become short of breath. The only pain fibers in the lung are on the surface of the lung, in the area known as the pleura. Chest pain may develop if the outer pleural aspects of the lung are involved. This pain is usually sharp and worsens when taking a deep breath, known as pleuritic pain.
In other cases of pneumonia, there can be a slow onset of symptoms. A worsening cough, headaches, and muscle aches may be the only symptoms. In some people with pneumonia, coughing is not a major symptom because the infection is located in areas of the lung away from the larger airways. At times, the individual's skin color may change and become dusky or purplish (a condition known as "cyanosis") due to their blood being poorly oxygenated.
Children and babies who develop pneumonia often do not have any specific signs of a chest infection but develop a fever, appear quite ill, and can become lethargic. Elderly people may also have few symptoms with pneumonia.



SKABIES
Background
Human scabies is an intensely pruritic skin infestation caused by the host-specific mite, Sarcoptes scabiei var hominis. Scabies has been a source of human infestation for more than 2500 years, dating back to Roman times. Originally, the Romans used the term scabies to denote any pruritic skin disease. In the 17th century, Giovanni Cosimo Bonomo identified the mite as one cause of scabies. The name Sarcoptes scabiei is derived from the Greek words sarx (the flesh) and koptein (to smite or cut) and the Latin word scabere (to scratch).1
Today, the term scabies refers to the skin lesions produced by this mite. A readily treatable infestation, scabies remains common primarily because of diagnostic difficulty, inadequate treatment of patients and their contacts, and improper environmental control measures. Scabies is a great clinical imitator. Its spectrum of cutaneous manifestations and associated symptoms often results in delayed diagnosis. In fact, the phrase "7-year itch" was first used with reference to persistent, undiagnosed infestations with scabies.
Scabies is a worldwide public health problem, affecting persons of all ages, races, and socioeconomic groups. Overcrowding, delayed diagnosis and treatment, and poor public education contribute to the prevalence of scabies in both industrial and nonindustrial nations. Prevalence rates are higher in children and sexually active individuals than in other persons. Patients with poor sensory perception due to entities such as leprosy and persons with immunocompromise due to conditions such as status posttransplantation, HIV disease, and old age are at particular risk for the crusted variant. These populations present with clinically atypical lesions and often are misdiagnosed, thus delaying treatment and elevating the risk of local epidemics.

For a pediatric perspective, see the eMedicine article Scabies.
Pathophysiology
Human scabies is caused by the S scabiei mite, var hominis, an obligate human parasite and is shown in the image below.

Scabies mite scraped from a burrow (original magnification, 400X).
[ CLOSE WINDOW ]

Scabies mite scraped from a burrow (original magnification, 400X).

Animal scabies mites may result in transient symptoms in humans, but they are not a cause of persistent infestations. The most efficient means of transmission is via direct and prolonged contact with an infected individual. Mites can survive up to 3 days away from human skin, so fomites such as infested bedding or clothing are an alternate but infrequent source of transmission.

The entire life cycle of the mite lasts 30 days and is spent within the human epidermis. After copulation, the male mite dies and the female mite burrows into the superficial skin layers and lays a total of 60-90 eggs. The ova require 10 days to progress through larval and nymph stages to become mature adult mites. Less than 10% of the eggs laid result in mature mites.

Mites move through the top layers of skin by secreting proteases that degrade the stratum corneum. They feed on dissolved tissue but do not ingest blood. Scybala (feces) are left behind as they travel through the epidermis, creating linear lesions clinically recognized as burrows.

An affected individual harbors a variable number of living mites, typically less than 100 and usually no more than 10-15. In immunocompromised hosts, the weak immune response fails to control the disease and results in a fulminant hyperinfestation termed crusted scabies. The number of mites in a patient with crusted scabies can exceed 1 million. In these cases, the mite can survive off the host for up to 7 days, feeding on the sloughed skin in the local environment such as bedsheets, clothing, and chair covers. Failure to implement environmental control measures in this situation may result in relapse and reinfestation after successful treatment of the host.

Certain patient populations are susceptible to crusted scabies. These include patients with primary immunodeficiency disorders or a compromised ability to mount an immune response secondary to drug therapy. A modified host response may be a key factor in patients with malnutrition. Motor nerve impairments result in the inability to scratch in response to the pruritus, thus disabling the utility of scratching to remove mites and destroy burrows. Rare cases immunocompetent patients developing the crusted variant without clear explanation have been described.

The incubation period prior to onset of symptoms depends on whether the infestation is an initial exposure or a relapse/reinfestation. Upon initial infestation, a delayed type IV hypersensitivity reaction to the mites, eggs, or scybala develops over the ensuing 4-6 weeks. Previously sensitized individuals can develop symptoms within hours of reexposure. The hypersensitivity reaction is responsible for the intense pruritus that is the clinical hallmark of the disease.
Frequency
International
Approximately 300 million cases of scabies are reported worldwide each year. In developed countries, scabies epidemics occur primarily in institutional settings such as prisons and long-term care facilities such as nursing homes and hospitals.2 Prevalence rates in developing countries are higher than those in developed nations. Natural disasters, war, and poverty lead to overcrowding and increased rates of transmission.
Mortality/Morbidity
Complications of scabies are rare and generally result from vigorous rubbing and scratching. Disruption of the skin barrier puts the patient at risk for secondary bacterial invasion, primarily by Streptococcus pyogenes and Staphylococcus aureus. Superinfection with S pyogenes can precipitate acute poststreptococcal glomerulonephritis and even rheumatic fever. More common pyodermas include impetigo and cellulitis, which may rarely result in sepsis. Scabies infestations can exacerbate underlying eczema, psoriasis, Grover disease, and other preexisting dermatoses. Even with appropriate treatment, scabies can leave in its wake residual eczematous dermatitis and/or postscabietic pruritus, which can be debilitating and recalcitrant.

Crusted scabies carries an increased mortality rate because of the frequency of secondary bacterial infections resulting in sepsis.
Race
No racial predilection has been proven for scabies.
Sex
No predilection is recognized for scabies.
Age
Classic scabies is more common in children and in people who are sexually active. Crusted scabies occurs predominantly in patients who are immunocompromised, elderly, institutionalized, or bedridden.
Clinical
History
The historical aspects of scabies infestations are quite reliable in suggesting the diagnosis. Lesion distribution, intractable pruritus that is worse at night, and similar symptoms in close contacts should immediately rank scabies at the top of the clinical differential diagnosis.
Lesion distribution differs in adults and children. Adults manifest lesions primarily on the flexor aspects of the wrists, the interdigital web spaces of the hands, the dorsal feet, axillae, elbows, waist, buttocks, and genitalia. Pruritic papules and vesicles on the scrotum and penis in men and areolae in women are highly characteristic.
Infants and small children may develop lesions diffusely, but unlike adults, lesions are common on the face, scalp, neck, palms, and soles. All cutaneous sites are susceptible in immunocompromised and elderly patients, who often have a history of a widespread, pruritic eczematous eruption.

Consider the diagnosis of scabies in any patient presenting with a recent onset of intense itching that is accentuated at night.
Physical
Clinical findings include both primary and secondary lesions. Primary lesions are the first manifestation of the infestation, and these typically include small papules, vesicles, and burrows. Secondary lesions are the result of rubbing and scratching, and they may be the only clinical manifestation of the disease. If so, the diagnosis must be inferred by the history, lesion distribution, and accompanying symptoms.
• Primary scabies lesions
o The distribution is highly characteristic in typical cases.
o Burrows are a pathognomonic sign and represent the intraepidermal tunnel created by the moving female mite. They appear as serpiginous, grayish, threadlike elevations ranging from 2-10 millimeters long, as seen in the image belong