Anaphylaxis is the medical term for a severe allergic reaction that can affect the entire body and is potentially life threatening. An anaphylactic reaction can lead to shock, hence the term anaphylactic shock. Anaphylaxis presents with the same signs and symptoms of shock in addition to an itchy skin rash, airway constriction, nausea, vomiting or diarrhea.

Anaphylaxis is known as a type I hypersensitivity reaction and occurs within 15 to 30 minutes of being exposed to the antigen (foreign organisms or substance). Sometimes a severe reaction can occur within seconds. This reaction is mediated by immunglobulin E (IgE), which is a type of antibody. Antibodies are developed by the immune system to help immune cells identify antigens  as being dangerous and triggering a reaction against them. IgE tends to reside within the respiratory passages, skin and mucus membranes. Therefore much of the symptoms of this type of hypersensitivity reaction occurs in these areas.

Milder type I hypersensitivity reactions may be seen in acute allergies and chronic allergic conditions like asthma and hay fever. Anaphylaxis, however, is a much more severe reaction commonly triggered by certain drugs, foods or insect toxins (from bites or stings). Unlike a mild allergic reaction, anaphylaxis requires emergency medical attention so that epinephrine can be administered. Failure to do so can sometimes lead to death.

The word aspiration in the medical context means to take in or suck up. While these two meanings may appear contradictory, they are relevant to the context in which they are used. For example if the stomach contents are taken into the lungs when vomiting then this is aspiration in the context of taking in. However in another situation, like during liposuction when fat is sucked up, this is also referred to as aspiration. In the latter scenario, aspiration means ‘to remove’.

Anasarca is the medical term for simultaneous swelling throughout the body (generalized edema). The fluid accumulates within the subcutaneous tissue of the skin and gross swelling of the body is evident. There may also be other types of edema occurring simultaneously like ascites, which is fluid accumulation within the abdominal cavity (swollen stomach). Other cavities and organs may also be affected by edema.

There are various diseases that cause edema, some of which result in localized swelling while others can lead to anasarca. This may vary from cardiovascular (heart and blood vessels) to kidney and liver diseases, certain pharmaceutical drugs and different types of autoimmune diseases like SLE (lupus). Anasarca usually indicates severe illness and may often be seen in the end stages of serious chronic conditions.

Anasarca gives the appearance of being swollen or bloated throughout most of the body and should not be mistaken for weight gain. Immediate medical attention is required if anasarca is evident.

Amenorrhea is the medical term for absent menses (no period). Missing a single period is not considered as amenorrhea although this should not occur in a healthy female unless there are short term disturbances. Amenorrhea is a total lack of menstruation that occurs for 6 months or more. There are two types of amenorrhea – primary and secondary amenorrhea.

Primary amenorrhea is the lack of menstruation in a girl who is 16 years or older or if there are signs of puberty present for more than 2 years with no menses. This means that menarche (the onset of menstruation) has not occurred as yet under the the abovementioned conditions.

Secondary amenorrhea is when menses is absent for 6 consecutive months or more in a girl or woman who was previously menstruating. Pregnancy and menopause are two common causes that are not pathological but there are other causes that may be a result of minor or serious medical conditions.

Anovulation is the medical term for the absence of ovulation. The ovary releases a mature egg cell into the fallopian tube during the menstrual cycle and this process is known as ovulation. It can occur approximately 14 to 16 days before the start of menstruation (refer to Ovulation Schedule). In anovulation, this process does not occur.

The ovary may not release a mature egg cell for a number of reasons including ovarian disorders, menopause or perimenopause, pregnancy, hormone contraceptives, drugs or even severe stress, exercise and starvation (including strict dieting).  Other chronic conditions, even those that are not gynecological in origin, may result in anovulation.

continue reading What is Anovulation? No Ovulation

An aneurysm is a balloon or bulge at one area of the artery wall. When the artery wall weakens at a spot along the course of the vessel, it is prone to ballooning due to  blood collecting within the sac-like pouch. This ballooning continues to add stress to the already compromised vessel wall and can rupture. This can be fatal.

A aneurysm can affect any artery but tends to occur more frequently in the aorta or cerebral artery. Aneurysms do not always appear like a balloon extending from the wall. At times it may appear like a bulge or widening of the artery at the affected area.

continue reading What is an Aneurysm? Artery Balloon, Bulge

The aorta is the artery that carries oxygen-rich blood out of the left ventricle of the heart. As the largest artery in the body, it has many branches which helps distribute the oxygenated blood to organs and tissues.

Typically the aorta starts from the top of the heart (ascending aorta), curves downwards (arch of the aorta) and continues downwards (descending aorta). The part of the descending aorta that runs through the chest (thoracic cavity) is known as the thoracic aorta while the part that runs below the diaphragm, through the abdomen is known as the abdominal aorta.

continue reading What is the Aorta?

Anterior is the anatomical term for indicating that an organ or structure is towards the front of the body.

It is usually  used to indicate the position in relation to another organ or structure and may mean that it is ‘in front of’ another organ or structure.

For example – in a person who is standing erect, the tip of the nose is anterior to the eyes meaning that the nose tip is in front of or located before the eyes.

The term anterior may also be used to indicate ‘towards the head’ because isolating the front and rear (posterior) orientation may be misleading in certain situations, especially in certain animals.

To prevent ambiguity, anterior is regarded as the position towards the front or in front of another organ or structure when a person is in the standard anatomical position for humans (refer to picture) which is standing erect, with the feet together, upper limbs slightly away from the sides of the body with the palms facing forward and the thumb pointing away from the body.

Aerophagia is the swallowing of air meaning that air enters the gastrointestinal tract (gut) rather than the lungs. The air may get trapped in the esophagus and/or stomach temporarily and may be passed with an eructation (belch or burp). Aerophagia is not a serious condition but may lead to gas bloating, indigestion and abdominal discomfort. The most noticeable symptom though is excessive belching.

continue reading What is Aerophagia?

Atrophy is a decrease in size of a part of a body. This can affect an organ, tissue or cell. Atrophy may be attributed to a decrease in size of individual cells or a reduced number of cells in the affected organ or tissue. Atrophy is usually acquired, meaning it is the result of a disease (pathological atrophy) or some change in condition within the body (physiological atrophy).

Atrophy is commonly referred to as ‘wasting’ and while it usually affects one or a few areas of the body at a time, it can also affect large parts of the body. This generalized wasting which is usually associated with fatigue and a lack of appetite or malnutrition is seen in certain chronic diseases like cancer or AIDS and is known as cachexia. Atrophy in these cases may not be reversible, especially in the latter stages of the disease that precede death. Depending on the cause, severity and site that is affected, atrophy may be reversed although this may take a long period of time and require medical treatment and other therapeutic measures.

continue reading What is Atrophy?