Hereditary angioedema is a condition caused by a lack of C1 esterase inhibitor, a protein that is part of the complement system. It is typically inherited in an autosomal dominant manner. Symptoms usually start in childhood and continue sporadically into adulthood. Attacks can be triggered by minor surgical procedures, dental work, and stress. The main clinical signs of hereditary angioedema include swelling of the skin and mucous membranes, with the face, tongue, and extremities being the most commonly affected areas. There is often a tingling sensation before an attack, sometimes accompanied by a non-itchy rash.

Angioedema and anaphylaxis resulting from C1 esterase inhibitor deficiency do not respond to adrenaline, steroids, or antihistamines. Treatment requires the use of C1 esterase inhibitor concentrate or fresh frozen plasma, both of which contain C1 esterase inhibitor. In situations that may trigger an attack, short-term prophylaxis can be achieved by administering C1 esterase inhibitor or fresh frozen plasma infusions prior to the event. For long-term prevention, androgenic steroids like stanozolol or antifibrinolytic drugs such as tranexamic acid can be used.

Tryptase levels can be a valuable tool in diagnosing anaphylaxis. During an anaphylactic reaction, mast cell tryptase is released and can be measured in the blood. Research suggests that tryptase levels reach their highest point in the blood within 1 minute to 6 hours after the reaction begins, typically peaking around 1-2 hours after the onset of symptoms. This information is crucial for diagnosing and treating anaphylaxis, especially in cases where the diagnosis is uncertain. It’s important to note that tryptase levels may return to normal within 6 hours, so the timing of blood samples is crucial. The current recommendation is to take three tryptase level measurements: one as soon as resuscitation begins, another 1-2 hours after symptoms start, and a third 24 hours later or during the recovery period. It’s worth mentioning that some individuals may have elevated baseline tryptase levels, which should be taken into consideration during the diagnosis process.

Further Reading:

Anaphylaxis is a severe and life-threatening hypersensitivity reaction that can have sudden onset and progression. It is characterized by skin or mucosal changes and can lead to life-threatening airway, breathing, or circulatory problems. Anaphylaxis can be allergic or non-allergic in nature.

In allergic anaphylaxis, there is an immediate hypersensitivity reaction where an antigen stimulates the production of IgE antibodies. These antibodies bind to mast cells and basophils. Upon re-exposure to the antigen, the IgE-covered cells release histamine and other inflammatory mediators, causing smooth muscle contraction and vasodilation.

Non-allergic anaphylaxis occurs when mast cells degrade due to a non-immune mediator. The clinical outcome is the same as in allergic anaphylaxis.

The management of anaphylaxis is the same regardless of the cause. Adrenaline is the most important drug and should be administered as soon as possible. The recommended doses for adrenaline vary based on age. Other treatments include high flow oxygen and an IV fluid challenge. Corticosteroids and chlorpheniramine are no longer recommended, while non-sedating antihistamines may be considered as third-line treatment after initial stabilization of airway, breathing, and circulation.

Common causes of anaphylaxis include food (such as nuts, which is the most common cause in children), drugs, and venom (such as wasp stings). Sometimes it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis.

The Resuscitation Council (UK) provides guidelines for the management of anaphylaxis, including a visual algorithm that outlines the recommended steps for treatment.

The management of anaphylaxis involves several important steps. First and foremost, it is crucial to ensure proper airway management. Additionally, early administration of adrenaline is essential, preferably in the anterolateral aspect of the middle third of the thigh. Aggressive fluid resuscitation is also necessary. In severe cases, intubation may be required. However, it is important to note that the administration of chlorpheniramine and hydrocortisone should only be considered after early resuscitation has taken place.

Adrenaline is the most vital medication for treating anaphylactic reactions. It acts as an alpha-adrenergic receptor agonist, which helps reverse peripheral vasodilatation and reduce oedema. Furthermore, its beta-adrenergic effects aid in dilating the bronchial airways, increasing the force of myocardial contraction, and suppressing histamine and leukotriene release. Administering adrenaline as the first drug is crucial, and the intramuscular (IM) route is generally the most effective for most individuals.

The recommended doses of IM adrenaline for different age groups during anaphylaxis are as follows:

– Children under 6 years: 150 mcg (0.15 mL of 1:1000)
– Children aged 6-12 years: 300 mcg (0.3 mL of 1:1000)
– Children older than 12 years: 500 mcg (0.5 mL of 1:1000)
– Adults: 500 mcg (0.5 mL of 1:1000)

Type I hypersensitivity reactions are allergic reactions that occur when a person is exposed again to a particular antigen, known as an allergen. These reactions are triggered by IgE and typically happen within 15 to 30 minutes after exposure to the allergen.

A rapid onset of an urticarial rash, which occurs shortly after being exposed to an allergen (such as latex), is highly likely to be caused by a type I hypersensitivity reaction.

The management of anaphylaxis involves several important steps. First and foremost, it is crucial to ensure proper airway management. Additionally, early administration of adrenaline is essential, preferably in the anterolateral aspect of the middle third of the thigh. Aggressive fluid resuscitation is also necessary. In severe cases, intubation may be required. However, it is important to note that the administration of chlorpheniramine and hydrocortisone should only be considered after early resuscitation has taken place.

Adrenaline is the most vital medication for treating anaphylactic reactions. It acts as an alpha-adrenergic receptor agonist, which helps reverse peripheral vasodilatation and reduce oedema. Furthermore, its beta-adrenergic effects aid in dilating the bronchial airways, increasing the force of myocardial contraction, and suppressing histamine and leukotriene release. Administering adrenaline as the first drug is crucial, and the intramuscular (IM) route is generally the most effective for most individuals.

The recommended doses of IM adrenaline for different age groups during anaphylaxis are as follows:

– Children under 6 years: 150 mcg (0.15 mL of 1:1000)
– Children aged 6-12 years: 300 mcg (0.3 mL of 1:1000)
– Children older than 12 years: 500 mcg (0.5 mL of 1:1000)
– Adults: 500 mcg (0.5 mL of 1:1000)

Adrenaline is the most crucial drug in treating anaphylaxis. It is essential to be aware of the appropriate dosage and administration method for all age groups. Additionally, high flow oxygen should be administered, as mentioned in the question stem. While there are other drugs that should be given, they are considered less important than adrenaline. These include IV fluid challenge, slow administration of chlorpheniramine (either IM or IV), slow administration of hydrocortisone (particularly in individuals with asthma), and the consideration of nebulized salbutamol or ipratropium for wheezing individuals (especially those with known asthma).

Further Reading:

Anaphylaxis is a severe and life-threatening hypersensitivity reaction that can have sudden onset and progression. It is characterized by skin or mucosal changes and can lead to life-threatening airway, breathing, or circulatory problems. Anaphylaxis can be allergic or non-allergic in nature.

In allergic anaphylaxis, there is an immediate hypersensitivity reaction where an antigen stimulates the production of IgE antibodies. These antibodies bind to mast cells and basophils. Upon re-exposure to the antigen, the IgE-covered cells release histamine and other inflammatory mediators, causing smooth muscle contraction and vasodilation.

Non-allergic anaphylaxis occurs when mast cells degrade due to a non-immune mediator. The clinical outcome is the same as in allergic anaphylaxis.

The management of anaphylaxis is the same regardless of the cause. Adrenaline is the most important drug and should be administered as soon as possible. The recommended doses for adrenaline vary based on age. Other treatments include high flow oxygen and an IV fluid challenge. Corticosteroids and chlorpheniramine are no longer recommended, while non-sedating antihistamines may be considered as third-line treatment after initial stabilization of airway, breathing, and circulation.

Common causes of anaphylaxis include food (such as nuts, which is the most common cause in children), drugs, and venom (such as wasp stings). Sometimes it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis.

The Resuscitation Council (UK) provides guidelines for the management of anaphylaxis, including a visual algorithm that outlines the recommended steps for treatment.
https://www.resus.org.uk/sites/default/files/2021-05/Emergency%20Treatment%20of%20Anaphylaxis%20May%202021_0.pdf

An EpiPen is a device that automatically injects adrenaline and is used to treat anaphylaxis. It is often given to individuals who are at risk of experiencing anaphylaxis so that they can administer it themselves if needed.

It is important for healthcare professionals to be familiar with the various auto-injector devices that are commonly available. In the event that an adrenaline auto-injector is the only option for treating anaphylaxis, healthcare professionals should not hesitate to use it.

Each EpiPen auto-injector contains a single dose of 0.3 mg of adrenaline. For children, there is also a version called EpiPen Jr that contains a single dose of 0.15 mg of adrenaline.

Corticosteroids can be beneficial in preventing or reducing prolonged reactions. According to the current APLS guidelines, the recommended doses of hydrocortisone for different age groups are as follows:

– Children under 6 months: 25 mg administered slowly via intramuscular (IM) or intravenous (IV) route.
– Children aged 6 months to 6 years: 50 mg administered slowly via IM or IV route.
– Children aged 6 to 12 years: 100 mg administered slowly via IM or IV route.
– Children over 12 years: 200 mg administered slowly via IM or IV route.
– Adults: 200 mg administered slowly via IM or IV route.

It is important to note that the most recent ALS guidelines do not recommend the routine use of corticosteroids for treating anaphylaxis in adults. However, the current APLS guidelines still advocate for the use of corticosteroids in children to manage anaphylaxis.

Type I hypersensitivity reactions are allergic reactions that occur when a person is exposed again to a particular antigen, known as an allergen. These reactions are triggered by IgE and typically happen within 15 to 30 minutes after exposure to the allergen.

A rapid onset of an urticarial rash, which occurs shortly after being exposed to an allergen (such as latex), is highly likely to be caused by a type I hypersensitivity reaction.

Urticaria is a condition characterized by a raised, itchy rash on the skin and mucous membranes. It can be localized or widespread and affects about 15% of people at some point in their lives. There are two forms of urticaria: acute and chronic, with the acute form being more common.

In about 50% of cases of acute urticaria, a specific trigger can be identified. Common triggers include allergies (such as foods, bites, stings, and drugs), skin contact with irritants (like chemicals, nettles, and latex), physical stimuli (such as firm rubbing, pressure, and extremes of temperature), and viral infections.

The main skin lesion seen in urticaria is called a wheal or wheel. Wheals typically have three characteristics: a central swelling that can be red or white in color, surrounded by a red area (known as the flare), and they are usually very itchy, sometimes accompanied by a burning sensation. Wheals are temporary and usually disappear within 1 to 24 hours, returning the skin to its normal appearance.

Wheals can vary in size, ranging from a few millimeters to lesions as large as 10 cm in diameter. They can appear as single lesions or multiple ones, and sometimes they merge together to form large patches. In some cases, urticaria can also cause swelling of the soft tissues in the eyelids, lips, and tongue, known as angioedema.