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Category: Emergency Medicine

Adrenaline in Anaphylactic Shock and Other Drugs for it

Adrenaline in Anaphylactic Shock and Other Drugs for it

  • What is adrenaline?
    Adrenaline, or epinephrine, is a catecholamine secreted by the adrenal medulla and is one of the hormones released during stressful situations. Other catecholamines synthesised in the body are noradrenaline (norepinephrine) and dopamine. Structurally it contains a 3,4-dihydroxybenzene group.

The principal catecholamines of the body are formed by hydroxylation and decarboxylation of the amino acid, tyrosine. Adrenaline is formed by methylation of noradrenaline, which is formed from tyrosine in neurons secreting catecholamines. Enzyme phenylethanolamine-N-methyltransferase (PNMT) catalyses this reaction and is found in the brain and adrenal medulla.
The normal level of free epinephrine in plasma is about 30 pg/mL (0.16 nmol/L).

The adrenal medulla has receptors which when sympathetically stimulated by norepinephrine release epinephrine into the blood stream.

Mechanism of action
Adrenaline acts by stimulating adrenergic receptors. It has non-selective action and hence stimulates all adrenergic receptors:
• Alpha-1
• Alpha-2
• Beta-1
• Beta-2
• Beta-3

On binding to these receptors they stimulate formation of cyclic AMP which brings about further actions.

Physiologic actions
Epinephrine exerts sympathomimetic effects on the body.
• Heart: it has cardiac stimulant actions and causes increase in contractility, heart rate and cardiac output
• Blood vessels: it mediates vasoconstriction in the skin, mucous membranes and viscera ( alpha action) but dilatation in the liver and skeletal muscles (beta-2 action) with a net rise in the systolic blood pressure
• Respiratory system: adrenaline causes bronchodilation and also inhibits the release of allergic mediators from mast cells
• Hyperglycemia
• Initiation of lipolysis

Therapeutic uses
Generally this drug is used in emergency situations like the following:
1. Anaphylactic shock
2. Bronchospasm
3. Cardiopulmonary arrest
Besides the above mentioned scenarios adrenaline may also be used, in low concentrations (1:100000 parts), to increase the duration of local anaesthesia.

Use in anaphylactic shock
Anaphylactic shock
​Anaphylactic shock is an immediate type of hypersensitivity (type I) reaction. This occurs in response to exposure to an allergen to which the body has been hypersensitised and hence an unwanted, dangerous reaction occurs. Typical symptoms include a rash, nausea, vomiting, difficulty in breathing and shock.
​The best route for administration is the intramuscular route and the best site for injection is the anterolateral aspect of the middle one-third of the thigh. (An IV route is not preferred because it has a greater risk of causing harmful side effects since adrenaline is very potent even in small amounts.)
The usual dose for adults is 0.5 mg IM (i.e. 0.5 mL of 1:1000) adrenaline.
​Mechanism of action
​Action of adrenaline in anaphylaxis is basically a manifestation of its physiologic actions. It induces vasoconstriction which reduces the erythema of rashes.
Bronchodilating effect relieves dyspnoea.
Perhaps the most important effect of adrenaline here is the inhibition of mast cells which play an active part in anaphylaxis. As a result mediators of allergy, such as histamine, serotonin, are not released and the reaction is controlled.
Other drugs
Apart from adrenaline, nowadays several other drugs have emerged for treating a case of anaphylaxis.
Antihistamines (such as diphenhydramine and hydroxyzine) are one such choice. These act by blocking the H1 receptors of histamine which plays an important role in the reaction. Sometimes a combination of H1 and H2 blockers may also be used. However these have to be continued for 2-3 days after the attack.
​Inhaled beta-2 agonists (such as albuterol) may also be used. They act by relaxing the bronchial smooth muscles and thus reducing dyspnoea. These are administered to patients who appear with wheezing.
Glucocorticoids (such as methylprednisolone) prevent inflammation by suppressing the migration of polymorphonuclear leucocytes and fibroblasts, decreasing capillary permeability and stabilising lysosomes at the cellular level.
​Lesser used drugs include glucagon and dopamine which help in relieving symptoms. But these are used in adjunct with epinephrine and not alone. Dopamine may be used alone but requires high doses.

Somatoform Disorders

Somatoform Disorders

These are a group of disorder in which the patient presents with multiple clinically significant feature and physical symptoms that cannot be explained.These unexplained physical attributes often leads to anxiety of the patient; We don’t actually understand the actual mechanism of these disorders. There can be a problem with the nerve impulse that send signals of pain, pressure and other unpleasant sensation to the brain.They tend to come and go .Though various underlying causes tends to increase the risk of such disorders.
1. Its mostly occurs in subject under 30 years of age.
2. Genetics has a profound influence over such disorders
3. Negative attitude towards life.
4. Unusual sensitivity towards physical and emotional pain.
5. Family history may be positive.

Clinical criteria which are common to all the somatoform disorder are
1. Cannot be explained by medical condition, another mental disorder, or effect of a substance,
2. Not related to factitious disorder and malingering.
3. Cause significant impairment of social functioning and occupational and other functioning.

Characteristics of Somatoform Disorders


1. Hypochondriasis- Subject affected with this type of disorder are always in a false belief that they are suffering from a serious illness.The belief is not fixed and could be removed transiently by explanation and reasoning to have another belief about another organ of the body.The patient expresses fear while discussing their symptom.The patient must have a non delusional preoccupation with their symptoms at least six months before diagnosis can be made.
2. Conversion disorder- The neurological syndrome does not correlate with a medical cause.The symptoms are mainly weakness,tremour,deafness,blindness,etc. It though start as a mental or emotional crisis and converts to a physical problem.Conversion disorder is not conformed to any anatomical pathway or physiological mechanisms, but instead they fit a lay view of physiology. It rarely occurs below 10 years of age or after 35 years of age.It is commonly found in rural population, person of lower socioeconomic status , and those with minimal medical or psychological knowledge.
3. Pseudocyesis- Here the woman feel labour pain along with other indication of pregnancy. Here the somatic symptoms occur less than six months.
4. Body dysmorphic disorder- It is the obsession with with a flaw in his or her appearance which can either be a minor flaw or non-existing.In case of real physical imperfection, the defect is usually slight but the patient’s concern is excessive.The disorder occurs equally in men and women.
5. Somatization disorder- Also known as Briquet disorder, here the patients are
Below 30 years of age and present with unexplained physical symptoms .
The symptoms include-
• One pseudoneurogenic symptom
• One sexual problem
• Four pain symptom
• Two gastrointestinal problem
People with such disorder make frequent clinical visits , have multiple
Diagnostic test done, are referred to multiple doctor due to their myriad
6. Undifferentiated somatoform disorder- it is a less specific version of somatization , here it extends up to six months or longer , with one or more than one unexplained physical complain with other necessary clinical criteria.Chronic fatigue that is unexplained by any relevant clinical criteria is a typical symptom.
7. Pain disorder- It is fairly common. At its onset , the pain is associated with psychological factors. Though its maintenance may be associated with a general medical condition.Though pain is is the the focus of the disorder, but psychological factor are primary to play in the perception of pain.

Here the result of medical test are either normal or fails to explain the person’s symptoms.And the history and physical examination do not reveal any known medical condition.


It is quite a challenge to work with somatoform disorder it requires considering a mental health diagnosis while excluding the medical causes of the physical symptoms.The problem with these type of disorder is the that there is no specific physical examination or laboratory finding that are required for confirmation of the diagnosis.Though appropriate non psychiatric medical condition should be considered by unnecessary laboratory testing should be avoided in such cases.Factitious disorder and malingering though are related disorders should be excluded before diagnosing a somatoform disorder . In factitious disorder the patient has a internal desire to be sick , while in malingering the patient bluff the physical symptoms so that he may have any sort of gain such as financial benefit ,legal benefit , escaping a unfavorable situation. But in somatoform disorder, there is no possible gain for the patient and the physical symptoms are not feigned , rather fear and anxiety stimulates these disorders.

The diagnosis of Somatoform disorders have been assisted by clinical diagnostic tools such as patient health questionnaire .

If the patient is bothered a lot lot by at least three of the symptoms without a medical reason then there is a possibility of somatoform disorder.

The patient have a strong believe that their symptom have a physical cause , though is is contrary .This is due to the false interpretation of the symptoms.
The steps of the treatment are-
1. Discussing the key features of the diagnosis with the patient-
The initial steps in the treatment is to discuss about the disorder to the patient early in the work-up and, after ruling out organic pathology as the primary ethology for the symptom, to confirm the psychiatric diagnosis.The physician must first construct a therapeutic alliance with the patient.then the physician must review with the patient the therapeutic criteria for the suspected somatoform disorder. He must inform the patient that the goal of treatment is management rather than cure.
2. Therapy-
First and foremost is the treatment of the psychiatric comorbidities , since the psychiatric disorders are generally found in union with the co morbidities.
There is limited effectiveness of the pharmacological interventions.
Cognitive behavior therapy have been found to be effective in the somatoform disorder.It focuses on reducing cognitive distortions , imaginary belief , worry and behavior that lead to anxiety and somatic manifestation.

3. Follow up-
Regular and brief follow up with the physician is an important aspect of treatment.This is important for the maintainable of the therapeutic alliance with the physician .The patient can openly ventilate about their worries and the opportunity to be reassured repeatedly that their symptoms are not due to a physical condition

Practice Management Strategies for Somatoform Disorders:-
Accept that patients can have distressing, real physical symptoms and medical conditions with coexisting psychiatric disturbance without malingering or feigning symptoms
Consider and discuss the possibility of somatoform disorders with the patient early in the work-up, if suspected, and make a psychiatric diagnosis only when all criteria are met
Once the diagnosis is confirmed, provide patient education on the individual disorder using empathy and avoiding confrontation
Avoid unnecessary medical tests and specialty referrals, and be cautious when pursuing new symptoms with new tests and referrals
Focus treatment on function, not symptom, and on management of the disorder, not cure
Address lifestyle modifications and stress reduction, and include the patient’s family if appropriate and possible
Treat comorbid psychiatric disorders with appropriate interventions
Use medications sparingly and always for an identified cause
Schedule regular, brief follow-up office visits with the patient (five minutes each month may be sufficient) to provide attention and reassurance while limiting frequent telephone calls and “urgent” visits
Collaborate with mental health professionals as necessary to assist with the initial diagnosis or to provide treatment

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