Anaphylaxis

Anaphylaxis is a hypersensitive reaction due to contact through allergens. These allergens induce an immediate immune response that is life threatening in most occasions. Anaphylactic reactions produce various clinical symptoms such as urticaria, respiratory congestion and gastrointestinal disturbances. Anaphylactic response is caused by certain type of compounds which may include proteins, pollen, venom, hormones and also some food extracts. The immunoglobulin E or IgE is responsible for the onset of anaphylactic reaction when exposed to an allergen.

Mechanism of anaphylactic reaction

A series of reactions take place in the body when anaphylaxis is triggered. The IgE which has a half-life of two days, binds to the fragment crystallizable or FC receptor part of the basophils and mast cells. This process is activated when the person comes in contact with an allergen which in turn mediates cellular de granulation and their release of biogenic amines such as histamine and serotonin. The effects of these biogenic amines may include the smooth muscles which generally constrict at the bronchiolar region and broncho capillary venules. It also causes the arteriole dilation.

Anaphylactic responses are of different types and are associated with allergen sources of different kinds such as pollen, food, insects and also some drugs. It happens because of the antigen contact to which the patient had been previously exposed. This type of antigen is also called an allergen. Systemic anaphylaxis is a serious condition in which the mast cells of the connective tissue become activated resulting in dangerous effects such as airway obstruction, swelling of the epiglottis and ultimately suffocation. Systemic anaphylaxis proceeds into another condition called anaphylactic shock which happens because of suffocation induced by the respective allergen. In addition to these, anaphylaxis may also result because of extreme physical exercise. This condition is also called exercise induced urticaria. Allergies to food like eggs and milk are common among infants. Other than these, underlying conditions such as hay fever, asthma and eczema may also induce anaphylaxis if untreated.

Anaphylactic shock is widely reported in people after consuming foods such as peanuts and Brazil nuts. Such food products induce the anaphylactic reaction in an instant causing severe discomfort and sometimes death. Many people also experience anaphylactic reactions because of penicillin administration. Some reactions of anaphylaxis also include excess production of mucous in the mouth, nose and throat. Atopic patients are highly susceptible to anaphylaxis. Patients having an underlying atopic condition produce high amount of IgE antibodies and hence they must be monitored carefully.

Diagnosis of Anaphylaxis

Anaphylactic reaction is diagnosed based on clinical symptoms such as skin rash (insect bites), hoarse voice, chest congestion, breathing difficulty, diarrhea, vomiting and abdominal cramps. Identification of the source is the predominant factor in the diagnosis of anaphylactic reactions. Thorough examination of the cause with immediate life saving measures must be done. Anaphylaxis can be fatal if not managed properly.

Anaphylaxis Treatment

Avoid foods that induce the condition. In the case of anaphylactic reaction, medical attention must be sought immediately. Oral medications such as Benadryl or diphenhydramine are given. EpiPen or injectable epinephrine is the drug of choice to control the anaphylactic reaction. Intravenous antihistamine drugs and oral steroids are given for a period of time to prevent the reoccurrence of the anaphylactic reactions.

Anaphylactic shock

Anaphylactic shock is a severe allergic reaction that can be life threatening. Possible allergies could be some drug, food or insect bites. The body reacts very soon and results in symptoms such as abdominal cramps, difficulty in breathing, fainting, anxiety and tightening of the airways. Immediate treatment is needed. There is loss of blood pressure and the body is in shock. There might be raised bumps over the body.

Blood Transfusion

Blood transfusion is one of the important procedures administered in healthcare centers to meet surgical and trauma needs. This procedure is categorized under transfusion medicine section. Blood transfusion is a high-risk procedure as it involves multiple protocols and guidelines for safe and effective transfusion.

Guidelines and Procedure

Transfusion medicine has high significance as it involves the transfusion of blood and blood products depending upon the patient needs. Blood required for the transfusion is obtained from blood banks, which are established either by the government or privately following NCCLS standards for the blood banks. The standards are evaluated by organizations such as WHO to set a uniform and global protocol for safe transfusion. Blood transfusion is predominantly done to increase the percentage of hemoglobin in anemic patients and also to replace vital components such as platelets and serum proteins in some medical conditions. Other reasons for blood transfusion is to replace the amount of blood lost during surgery or trauma. Patients suffering thrombocytopenia (any disorder in which there is an abnormally low amount of platelets) might be in need of platelet transfusion.

Blood banks are authorized by the government to collect blood of different groups. Some of the rare groups include B negative, O negative and Bombay blood group. In these situations, the names and the address of these respective rare blood types are noted to ensure timely availability in case of a transfusion request. Cancer patients also require transfusion in case of conditions such as leukemia and malignant carcinomas associated with spleen or bone marrow. Leukocyte reduction procedure is followed in some transfusion centers in order to minimize the incidence of transfusion-associated allergic reactions. All donors are checked for a three-month gap before the subsequent transfusion to facilitate fresh blood collection from the donors containing viable red blood cells.

Different types of Blood transfusions:

Fresh Whole Blood: This is mostly needed during cardiac surgery or massive hemorrhage. Fresh Whole blood has RBC, plasma and fresh platelets.

Packed RBC: This is mostly needed to raise the hematocrit (the proportion of total blood volume that is composed of red blood cells).

Frozen packed RBC: Stored for nearly 3 years, frozen packed RBC is sparingly used. It is often used for rare blood groups. Patients suffering severe leukoagglutinin reactions or anaphylactic reactions might need this.

Leukocyte-Poor Blood: Patients who suffer severe leukoagglutinin reactions might need this. It is an expensive process as WBC are removed by centrifugation.

Precautions and risks

Transfusion is a very important procedure and hence primary analysis of the donor blood is done in order to avoid blood borne sepsis, transfusion allergies and organ damage. The donor blood is always cross-matched with the recipient's in order to check the compatibility of the blood. All procedures are documented to ensure safety and tracking of a transfusion procedure, as it is associated with medico-legal protocols. The A and B antigens are the first check before transfusion. In emergencies, type O/Rh-negative blood can be given to any recipient and usually packed cells are given. The Rh factor has also to be tested. Blood from the donor is also investigated for infections such as HIV 1&2, HBV, HCV, and VDRL to ensure safe transfusion.

Blood is collected from the healthy donor in a blood bank by administering venipuncture procedure from the brachial region. The obtained blood is transported for immediate need in surgeries or stored for few days in case of a scheduled surgery having the requirement for the particular blood group. The transfusion requirement is clearly stated in the surgical form and the blood bank technicians provide number of units required on the given date. Some of the common side effects associated with blood transfusions are infections of both viral and bacterial origin obtained from an infected donor. Receipt of blood contaminated with gram-negative bacteria often causes septic shock, Disseminated intravascular coagulation or DIA (a large amount of procoagulant enters the blood stream over a short period of time, overwhelming the body’s ability to replenish coagulation factors and causing bleeding) and acute kidney injury. Receipt of blood with gram-positive bacteria causes fever and Bacteremia (presence of bacteria in blood) but rarely causes sepsis.