Introduction:
Anaphylaxis is a clinical condition that can be fatal, especially during the third trimester of pregnancy. But it can occur during any part of life. The cumulative impact of aortocaval compression on the circulatory abnormalities of anaphylaxis makes it difficult to manage during the third trimester. Rapidly developing systemic hypersensitivity reactions like anaphylaxis have severe consequences. It is characterized by improper circulation to the skin or mucous membranes, and difficulty breathing, leading to fatal conditions. It frequently happens when allergies kick an IgE-mediated pathway that activates mast cells and causes an anaphylactic response.
Studies have shown that anaphylaxis is becoming more common in the general population, although it is still relatively rare. This is because increased cesarean birth rates worldwide would result in higher exposure to anesthetic medications and antibiotics during delivery, both of which are known to cause allergies during pregnancy and childbirth. This is also true during pregnancy due to increased exposure to possible allergens.
Anaphylactic shock symptoms are similar to pregnancy-related symptoms such as lower back discomfort, vulvar and vaginal itching, fetal distress, or preterm delivery. Events that occurred during anaphylaxis are left undiagnosed as there are no visible signs and symptoms of improvement. It is difficult to distinguish between severe hypotension caused by spinal and epidural anesthesia, cardiac and pulmonary distress, amniotic fluid embolism, or placental abruption during pregnancy and childbirth. Painful uterine contractions can also be a form of anaphylactic shock in pregnant and non-pregnant women, which is rare.
What Is the Ring and Messmer Grading Scale of Immediate Hypersensitivity?
Immediate hypersensitivity reactions caused by drugs or latex were described by Ring and Messmer.
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Grade I: (skin and mucous membrane signs): Widespread erythema and rash with or without angioedema.
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Grade II: (modifiable multi-visceral symptoms): Skin and mucous membrane signs with or without tachycardia, dyspnea, and gastrointestinal disorders.
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Grade III: (severe life-threatening single or multi-visceral symptoms): Cardiovascular collapse, tachycardia or bradycardia with or without cardiac dysrhythmia, bronchospasm, grade I signs, gastrointestinal disorders.
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Grade IV: Gastrointestinal disturbances, skin, mucous membrane signs, and heart arrhythmias.
Whereas hypersensitivity reactions of grades I and II are typically not life-threatening, grades III and IV are involved in severe clinical conditions that require immediate resuscitation. Antibiotics and latex are considered the main culprit for immediate allergic hypersensitivity during pregnancy and delivery, although there is no substantial epidemiological data to support it.
What Are the Clinical Signs and Symptoms of an Anaphylactic Reaction?
Depending on the location of the receptor, the severity of the reaction, and the mode of anesthetic administration, the allergic reactions mentioned above may occur. Early signs of neuraxial anesthesia may include malaise, pruritus, nausea, and breathlessness if the patient is conscious. However, under general anesthesia, they may go unnoticed, and bronchospasm or cardiovascular collapse may be the first recognized signs.
Symptoms arise within minutes of administering the triggering drug in almost 90% of instances. If symptoms do not appear until after induction or during anesthesia maintenance, allergies to latex, antibiotics, disinfectants, or local anesthetics should be the cause of hypersensitivity reactions. Cardiovascular symptoms (73.6%), cutaneous responses (69.6%), and bronchospasm are the most prevalent clinical characteristics.
What Is Immediate Hypersensitivity in Obstetrics?
Immediate hypersensitivity, which occurs during the third trimester of pregnancy, is a clinical condition that can be fatal. The growing uterus in the pregnant woman compresses the inferior vena cava, preventing venous return and lowering cardiac output. The peripheral vasodilatation and interstitial capillary leakage caused by allergy worsen the situation.
As a result, the first event might be prolonged hypotension, cardiovascular collapse, or cardiac arrest. The patient's vital prognosis is dependent on the restoration of hemodynamic stability. Because the subcutaneous vascular bed is prone to vasoconstriction from the beginning of anaphylaxis, mucocutaneous symptoms may develop only after the arterial blood pressure has returned to normal, suggesting the restoration of peripheral perfusion.
What Is the Differential Diagnosis of Anaphylaxis During Pregnancy and Labor?
Anaphylaxis in pregnancy has a broad differential diagnosis, which includes pulmonary thromboembolism, aortocaval compression, amniotic fluid embolism, heart disease, problems related to anesthesia, pulmonary separation, and edema, urticaria, and sepsis (including high or total neuraxial block and local anesthetic toxicity), sepsis, and postpartum hemorrhage.
The overlapping clinical characteristics of anaphylaxis with other acute obstetric morbidities might make identification difficult, especially during the development or presence of neuraxial block.
What Is the Management of Anaphylaxis During Pregnancy and Labor?
Immediately administer Adrenaline (Epinephrine is the first line of treatment for anaphylaxis during pregnancy).
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Remove the suspected offending medicine or substance.
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Call for assistance right away, especially for grade III and IV responses.
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Stop using anesthetics that promote vasodilation and harmful inotropic effects.
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To reduce aortocaval compression, position the patient in left lateral uterine displacement.
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In situations of grade III or IV responses, provide intravenous Epinephrine as soon as possible.
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Give a big bolus of fluid (crystalloid or colloid).
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To compensate for the increased oxygen use, maintain or secure the airway with 100 % oxygen.
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A cesarean delivery plan is required when anaphylaxis is diagnosed since it may result in cardiac arrest.
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Second-line treatment - After the initial line of treatment, if the condition of the patient is not stable, start with the second line of treatment. In most cases, the first line of treatment is sufficient to control anaphylaxis.
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The antagonist of histamine H1 receptors (intramuscular Promethazine 50 mg or intravenous 25 mg).
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The antagonist of the histamine H2-receptor (intravenous Ranitidine 50 mg).
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Vasopressor infusion (initial dosage of Noradrenaline 1-4 mcg/min).
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Bronchodilator inhalation (Salbutamol, Fenoterol, Ipratropium).
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Corticosteroids: (5 mg/kg intravenous hydrocortisone).
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Others include tranexamic acid, glucagon, and aminophylline.
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Conclusion:
The development of anaphylaxis during pregnancy is very rare. But if it occurs during the third trimester, it is fatal to both the mother and the fetus. Various causative agents such as latex, antibiotics, uterotonics, and colloids induce hypersensitivity during pregnancy. Identification of the agents which cause hypersensitivity and withdrawing them immediately will save the life of the newborn and the mother.
