Clinical diagnosis
Case 235
【Progress】
After a while, his symptoms recovered. He was not given medicine. Three weeks later, he was administered the second shot of the same vaccine as the first one, inducing no side effects.
【Discussion】
There are two kinds of anaphylaxis: Ig E related and non-Ig E related. The mechanism of Ig E related anaphylaxis is that the previous expose of antigen makes immune system producing Ig E. When repeated antigen is exposed, Ig E adhered mast cell and Ig E adhered basophils causes degranulation from their cells. The granules inside the cells including histamine and heparin cause skin itch and edema, occlusive larynx and spastic bronchial trees due to spasm of smooth muscle, hypo-tension due to peripheral vascular dilatation. Histamine functions to create thrombus whereas heparin interrupt to form thrombus (1). Then, mast cells and basophils secrete histamine and heparin together. This often occurs in case of ingestion of food such as egg and milk in children and in case of contrast medium injection for contrast-enhanced CT. Non-Ig E related anaphylaxis is caused by the direct activation of mast cells, indicating the speedy degranulation to the antigen without Ig E presence. In this situation, the previous antigen is no exposed. Non-Ig E anaphylaxis is known to occur in case of getting stung by hornets.
When we get vaccination to prevent COVID19, anaphylaxis by vaccination is threatened worldwide. Messenger RNA (mRNA) cannot be an antigen basically since it is instantly broke down when entering in the body but the substance covering mRNA for protection can be antigen for allergy. Anaphylaxis at the first vaccination indicates non-Ig E related and anaphylaxis at the second vaccination does Ig-E related. It is known side effects of fever and general fatigue occur especially at the second vaccination. Fever does not continue for long, short only for one or two days. Although general fatigue with hypotension is relevant with anaphylaxis, fever is a symptom not related with mast cells. Fever occurs when macrophages recognize unfamiliar with antigen and secrete IL6 to stimulate body temperature hypothalamic thermoregulatory center (2-4). It is supposed that thereafter, helper T cells recognize the antigen that was experienced previously and make a message of familiar antigen to macrophages, inducing halt to secrete IL6, and secrete cytokine to plasma cells, leading to produce antibody for antigens.
Vasovagal reflex mimics anaphylaxis. Vagal nerve is the longest of all cranial nerves and accommodates functions of heart, vessels, respiratory tracts and digestive organs. The right vagal nerve innervates cardiac sinus and the left vagal nerve innervates atrium-ventricle node. When vasovagal reflex occurs in the situation of pain or stress, it leads to emergence of sudden slow heart rate, hypotension and the loss of consciousness. The difference between vasovagal reflex and anaphylaxis is whether skin eruption occurs or not and whether tachycardia or bradycardia (5). Atropine sulfate is effective for vasovagal reflux and adrenalin and/or antihistamine, for anaphylaxis.
【Summary】
A seventy one year-old male experienced faintness and mild bradycardia a few minutes after the 1st shot of vaccine for COVID19. It implies vasovagal reflex clinically. It is borne in mind that there can happen anaphylaxis and vasovagal reflex after the shot of vaccination. There are two kinds of anaphylaxis: Ig E related and non-Ig E related. Ig E related anaphylaxis occurs in case of the second shot of vaccination with tachycardia by degranulation from their cells from Ig E adhered mast cell and Ig E adhered basophils. Non-Ig E related anaphylaxis by the direct activation of mast cells in case of getting stung by hornets. Vasovagal reflex occurs in the situation of pain or stress, causing sudden slow heart rate, hypotension and the loss of consciousness. The difference between vasovagal reflex and anaphylaxis is whether skin eruption occurs or not and whether tachycardia or bradycardia.
【References】
1.1. Maintz, L, et al. Histamine and histamine intolerance. The American Journal of Clinical Nutrition 2007; 85: 1185–1196
2.Krause A, et al. Cytokines derived from alveolar macrophages induce fever after bronchoscopy and bronchoalveolar lavage. Am J Respir Crit Care Med 1997;155:1793-1797.
3."Raised troponin and interleukin-6 levels are associated with a poor prognosis in COVID-19". Cardiac Rhythm News. 2 April 2020.
4.Banks WA, Kastin AJ, Gutierrez EG (September 1994). "Penetration of interleukin-6 across the murine blood-brain barrier". Neuroscience Letters. 179 (1–2): 53–6.
5.Santini M, et al. The effect of atropine in vasovagal syncope induced by head-up tilt testing. Eur Heart J. 1999;20:1745-1751
2021.6.16