Anaphylaxis: Difference between revisions
Feedback

From WikiLectures

Visual
No edit summary
 
(3 intermediate revisions by 2 users not shown)
Line 1: Line 1:
{{under construction}}
'''Anaphylactic [[shock]]''' is a severe circulation disorder caused by immunological mechanisms. We distinguish between severe forms (anaphylactic shock - with organ systems damage and a distributional shock) and less severe forms (mild skin conditions, [[urticaria]]l reaction).
{{englishcheck}}
{{formatcheck}}
{{editorcheck}}
 
'''Anaphylactic [[shock]]''' is a severe circulation disorder caused by immunological mechanisms. We distinguish severe forms (anaphylactic shock - with organ systems damage and a distributional shock) and less severe forms (mild skin conditions, [[urticaria]]l reaction).
:Voice changes, difficulty swallowing and [[dyspnoea]] are all signs of a severe course.
:Voice changes, difficulty swallowing and [[dyspnoea]] are all signs of a severe course.


== Clinical picture ==
== Clinical picture ==
[[File:BackRed.JPG|thumb|right|Skin of a patient with anaphylaxis]]
[[File:BackRed.JPG|thumb|right|The skin of a patient with anaphylaxis]]
The time etween [[antigen]] exposure and the onset of clinical signs is usually less than one hour, the delay depends on several factors: the patient's sensitivity, the route of allergen administration and the amount of allergen. In 20% of patients, we observe a two-phase course of an anaphylactic reaction, in which the symptoms appear 6–24 hours after the initial reaction.
The time between [[antigen]] exposure and the onset of clinical signs is usually less than one hour, the delay depends on several factors: the patient's sensitivity, the route of allergen administration and the amount of allergen. In 20% of patients, we observe a two-phase course of an anaphylactic reaction, in which the symptoms appear 6–24 hours after the initial reaction.
 
 
===== Skin and mucous membranes =====
===== Skin and mucous membranes =====
* Pruritus and erytematous flush.
* Pruritus and erythematous flush.
* [[Urticaria]], which is mediated by [[IgE]] is usually located at the site of the allergen exposure, such as insect bites.
* [[Urticaria]], which is mediated by [[IgE]] is usually located at the site of the allergen exposure, such as insect bites.
* [[Angioedema]] (more severe cases) = swelling of the lower dermis and the subcutaneous layer.
* [[Angioedema|Angiooedema]] (more severe cases) = swelling of the lower dermis and the subcutaneous layer.
::* Angioedema accompanied by urticaria is itchy.
::* Angiooedema accompanied by urticaria is itchy.
::* Non-pruritic angioedema is not a sign of hypersensitivity (eg. [[hereditary angioedema]]).
::* Non-pruritic angiooedema is not a sign of hypersensitivity (eg. [[hereditary angioedema|hereditary angiooedema]]).
* Damage of mucous membranes is characterized by pruritus and congestion of the conjunctiva, nasal mucosa and oral cavity.  
* Damage to mucous membranes is characterized by pruritus and congestion of the conjunctiva, nasal mucosa and oral cavity.
* Swelling of the lips or tongue can lead to difficulty swallowing, and in severe cases to respiratory distress.
* Swelling of the lips or tongue can lead to difficulty swallowing, and in severe cases to respiratory distress.


===== Respiratory system =====
===== Respiratory system =====
In the upper respiratory tract, there is life-threatening edema of the larynx and / or the epiglottis and other adjacent structures.
In the upper respiratory tract, there is life-threatening oedema of the larynx and / or the epiglottis and other adjacent structures.
:* Clinically, children may report a feeling of discomfort in the throat, difficult speech, hoarseness of voice.  
:* Clinically, children may report a feeling of discomfort in the throat, difficult speech, and hoarseness of voice.
:* Inspiratory [[stridor]] may appear.
:* Inspiratory [[stridor]] may appear.
Lower airway involvement resembles an [[asthma]] attack with expiratory dyspnea, cough and chest retractions.
Lower airway involvement resembles an [[asthma]] attack with expiratory dyspnea, cough and chest retractions.


===== Cardiovascular system =====
===== Cardiovascular system =====
Anaphylactic shock is a type of distributional shock. The cause of hypotension is extreme vasodilation, increased vascular permeability, [[capillary leak syndrome]].
Anaphylactic shock is a type of distributional shock. The cause of hypotension is extreme vasodilation, increased vascular permeability, and [[capillary leak syndrome]].
::The result is an intravascular volume depletion, and a toxic effect of released mediators cannot be ruled out pathophysiologically.
::The result is an intravascular volume depletion, and a toxic effect of released mediators cannot be ruled out pathophysiologically.
Clinically, we find a patient with hypotension, difficult-to-palpate pulsations, tachycardia, but pink periphery. We can often observe [[arrhythmias]], the ECG may show signs of myocardial ischemia.
Clinically, we find a patient with hypotension, difficult-to-palpate pulsations, tachycardia, but pink periphery. We can often observe [[arrhythmia]], the ECG may show signs of myocardial ischemia.
 
 
===== Central nervous system =====
===== Central nervous system =====
Dizziness, [[syncope]], [[convulsions]] or [[alterations of consciousness]] may appear. Clinical signs are caused by both hypoperfusion and CNS hypoxia and the direct toxic effect of released mediators.
Dizziness, [[syncope]], [[convulsions]] or [[alterations of consciousness]] may appear. Clinical signs are caused by both hypoperfusion and CNS hypoxia and the direct toxic effect of released mediators.
===== Gastrointestinal system =====
===== Gastrointestinal system =====
Damage includes nausea, vomiting, diarrhea and abdominal pain. Other symptoms include rhinorrhoea, profuse sweating, metallic taste in the mouth, feeling hot, skin burning or a feeling of danger.
Damage includes nausea, vomiting, diarrhoea and abdominal pain. Other symptoms include rhinorrhoea, profuse sweating, metallic taste in the mouth, feeling hot, skin burning or a feeling of danger.
 
 
 
=== Severe forms ===
=== Severe forms ===
;Death occurs in the 1.  hour after the reaction!
;Death occurs in the first hour after the reaction!
Severe forms occur '''immediately''' within minutes of [[allergen]] exposure (after drug application, after insect stings).
Severe forms occur '''immediately''' within minutes of [[allergen]] exposure (after drug application, after insect stings).


'''Symptoms:'''
'''Symptoms:'''
* General: nausea, chills, palmar and plantar pruritus, pallor, loss of consciousness, hypothermia, bronchospasm, laryngeal edema, [[vomiting]], diarrhea;
* General: nausea, chills, palmar and plantar pruritus, pallor, loss of consciousness, hypothermia, bronchospasm, laryngeal oedema, [[vomiting]], diarrhoea;
* Breathing: rapid, shallow, wheezing;
* Breathing: rapid, shallow, wheezing;
* Cardiovascular: tachycardia, [[hypotension]], intangible pulse, inaudible sounds, convulsions,
* Cardiovascular: tachycardia, [[hypotension]], intangible pulse, inaudible sounds, convulsions,
Line 54: Line 39:


'''Laboratory examination:'''
'''Laboratory examination:'''
Hemoconcentration, leucopenia, thrombocytopenia, [[hypoxemia]], [[hypocapnia]], later hypercapnia and [[acidosis]] with metabolic predominance also appear. Coagulation disorders in the form of [[DIC]] may occur.
Hemoconcentration, leucopenia, thrombocytopenia, [[hypoxemia]], [[hypocapnia]], later hypercapnia and [[acidosis]] with metabolic predominance also appear. Coagulation disorders in the form of [[DIC]] may occur.




=== Less severe forms ===
=== Less severe forms ===
Less severe forms are characterized by generalized erythema and [[edema]], including pharyngeal edema.  
Less severe forms are characterized by generalized erythema and [[edema|oedema]], including pharyngeal oedema.  
'''Symptoms:'''
'''Symptoms:'''
* bronchospasm, irritating cough, [[dyspnoea]].
* bronchospasm, irritating cough, [[dyspnoea]].


== Diagnosis ==
== Diagnosis ==
Rozhodující je klinika a určení etiologického agens.
The clinical picture and the determination of the etiological agent are crucial.


Stanovujeme celkové a [[Laboratorní stanovení specifických IgE protilátek|specifické '''IgE''']] a provádíme '''kožní testy''' (prick testy). Pro alergickou příčinu svědčí elevace '''eosinofilního kationického proteinu''' ([[ECP]]), zvýšení '''[[histamin]]u''' v plasmě a moči, průkaz '''[[Eozinofilní granulocyt|eozinofilů]]''' v bronchiálním nebo nosním sekretu. Experimentálně se stanovuje tryptáza, což je specifická proteáza [[Žírné buňky|mastocytů]].
We determine total and [[Laboratory asessment of specific IgE antibodies|specific '''IgE''']] and perform '''skin tests''' (prick tests). Elevation of '''eosinophilic cationic protein''' ([[ECP]]), an increase of '''[[histamine]]''' in both plasma and urine, and detection of '''[[eosinophils]]''' in bronchial or nasal secretion indicate an allergic cause. Tryptase, a specific [[mast cell]] protease, is determined experimentally.  


=== Differential diagnosis ===
=== Differential diagnosis ===
'''Vazovagální [[synkopa]]''' je charakterizována reakcí na bolest či stres. Nacházíme chladná akra, [[nauzea|nauzeu]], pocit na omdlení, oproti tomu nevidíme žádné kožní známky, ani známky obstrukce dýchacích cest. Typická je [[bradykardie]], zatímco u anafylaxe bývá kompenzačním mechanismem navozená tachykardie. U '''[[Hereditární angioedém|hereditárního angioneurotického edému]]''' není přítomen pruritus, v rodinné anamnéze často najdeme údaje o edémech či [[Sufokace|sufokaci]]. Diagnózu potvrdíme sníženou hladinou C1 inhibitoru komplementu a sníženou CH 50 aktivitou [[komplement]]u. '''[[Arytmie]]''' prokáže EKG vyšetření. U lidí s '''[[Hysterie|hysterickým záchvatem]]''' můžeme někdy taky objevit příznaky anafylaktické reakce. Zde je ke správné diagnóze nezbytné psychiatricko-psychologické vyšetření.
'''Vasovagal [[syncope]]''' is characterized by a response to pain or stress. We find cold acres, [[nausea]], and a feeling of fainting, on the other hand, we do not see any skin marks or signs of airway obstruction. [[Bradycardia]] is typical, while anaphylaxis induces tachycardia as a compensatory mechanism. Pruritus is not present in '''[[hereditary angioedema|hereditary angiooedema]]''', in the family history we often find data on oedema or [[suffocation]]. We confirm the diagnosis with decreased levels of C1 complement inhibitor and decreased CH 50 [[complement]] activity. '''[[Arrhythmia]]''' is shown in the ECG. In patients, with '''[[a hysterical attack|a hysterical attack,]]''' we can sometimes also find symptoms of an anaphylactic reaction. Here, a psychiatric-psychological examination is necessary for a correct diagnosis.


== Mechanism ==
== Mechanism ==
'''Anafylaktická reakce''' je život ohrožující proces, při kterém tělo nadměrně reaguje na styk s alergenem. Jedná se tedy o speciální druh [[Alergie|alergické reakce]]. Při styku s [[alergen]]em dojde k aktivaci imunitního systému. Aktivací zánětlivých faktorů dojde k zvýšení permeability cév a hromadnému přesunu [[intravaskulární]] tekutiny do intersticia. Tím se sníží objem intravaskulární tělesné tekutiny, dojde k [[Hypotenze|hypotenzi]] a člověk upadá do [[šok]]u.
'''An anaphylactic reaction''' is a life-threatening process in which the body reacts excessively to contact with an allergen. It is therefore a special type of [[Allergy|allergic reaction]]. Contact with an [[allergen]] activates the immune system. Activation of inflammatory factors increases vascular permeability and mass transfer of [[intravascular]] fluid into the interstitium. This reduces the volume of intravascular body fluid, which leads to [[hypotension]] and the patient falls into [[shock]].
Anafylaktická reakce je spouštěna třemi dobře známými mechanismy imunitní odpovědi na expozici cizí látky.
 
The anaphylactic reaction is triggered by three well-known mechanisms of the immune response to foreign substance exposure.
=== IgE mediated reaction ===
=== IgE mediated reaction ===
Představuje až 60 % anafylaktických reakcí. IgE protilátky se mohou tvořit již po prvním setkání člověka s cizím antigenem. Antigen může být prezentován samotný nebo ve vazbě na proteinový nosič. IgE se váže na receptory mastocytů a bazofilů. Při reexpozici antigenu → antigen vede k přemostění molekul IgE → degranulace těchto buněk a uvolnění různých rychle působících mediátorů.
It represents up to 60% of all anaphylactic reactions. IgE antibodies can be formed after a patient's first encounter with a foreign antigen. The antigen may be presented alone or in association with a protein carrier. IgE binds to mast cell and basophil receptors. Upon re-exposure to antigen → antigen leads to the bridging of IgE molecules → degranulation of these cells and release of various fast-acting mediators.  


=== Complement mediated reaction ===
=== Complement mediated reaction ===
Imunokomplexy aktivovaná kaskáda komplementu. Výsledkem je tvorba '''anafylatoxinů''' jako jsou C3a a C5a – přímým mechanismem spouští uvolňování mediátorů z bazofilů a mastocytů. Imunokomplexy aktivovaný komplement představuje reakce na [[Krevní transfúze|transfúzi krve]], krevní deriváty či plazmu. Komplementem zprostředkovaná anafylaxe nastává např. u pacientů s deficitem [[IgA]]. U těchto pacientů je prokázána tvorba autoprotilátek typu [[IgG]] proti IgA. Komplement může být aktivován i přímo kontrastními látkami, dialyzační membránou.
Immunocomplex-activated complement cascade. The result is the formation of '''anaphylatoxins''' such as C3a and C5a - the direct mechanism that triggers the release of mediators from basophils and mast cells. Immunocomplex activated complement is the reaction to [transfusion of blood|blood transfusion]], blood derivatives or plasma. Complement-mediated anaphylaxis occurs, for example, in patients with [[IgA]] deficiency. The formation of [[IgG]] anti-IgA antibodies has been demonstrated in these patients. The complement can also be activated directly by contrast agents  and the dialysis membrane.


=== Direct release of mediators and other mechanisms ===
=== Direct release of mediators and other mechanisms ===
* Mechanismus uvolnění mediátorů přímo, bez účasti IgE či komplementu, je dosud neznámý. Látky schopné této reakce jsou např. hyperosmolární látky jako je [[mannitol]], radiokontrastní látky, [[opiáty]], [[chinolony]] nebo [[vankomycin]].
* The mechanism of a direct mediator release, without the involvement of IgE or complement, is still unknown. Substances capable of this reaction are, for example, hyperosmolar substances such as [[mannitol]], radiocontrast substances, [[opiates]], [[quinolones]] or [[vancomycin]].
* Anafylaxe po podání [[Neopioidní analgetika|nesteroidních antirevmatik]] (NSAR), souvisí s blokádou syntézy [[prostaglandiny|prostaglandinů]], kterou NSAR způsobují, zvyšuje se tvorba [[leukotrieny|leukotrienů]] a startuje anafylaxe.
* Anaphylaxis after the administration of [[non-steroidal anti-inflammatory drugs ]] (NSAID) is associated with the blockade of [[prostaglandin]] synthesis caused by NSADs, [[leukotriene]] production increases and anaphylaxis is triggered.
* Námahou nebo chladem indukovaná anafylaxe je postavena na principu přímé histaminoliberace, ev. IgE zprostředkované reakce.
* Exercise or cold-induced anaphylaxis is based on the principle of direct histaminoliberation or IgE mediated reactions.
=== Působení mediátorů ===
=== The effect of mediators ===
* Uvolnění mediátorů v rámci degranulace – [[histamin]], [[tryptáza]], [[heparin]].
* Release of mediators in degranulation – [[histamine]], [[tryptase]], [[heparin]].
* Celá řada mediátorů anafylaxe vzniká syntézou ''de novo'' – prostaglandiny D2, leukotrieny, PAF, IL-4, 5, 6, 13, [[TNF]]α a adenosin.
* Many mediators of anaphylaxis are formed by ''de novo'' synthesis  – prostaglandins D2, leukotrienes, PAF, IL-4, 5, 6, 13, [[TNF]]α and adenosine.
'''Mediátory''' → rozvoj klinických známek anafylaktické reakce: bronchospasmus, zvýšení kapilární permeability, alterace hladkého svalstva systémových a plicních cév.
'''Mediators''' → development of clinical signs of anaphylactic reaction: bronchospasm, increased capillary permeability, alterations of systemic and pulmonary vascular smooth muscle.
:* '''Histamin''' vyvolává svědění, endoteliální dysfunkci, erytém, bronchokonstrikci a ztráty tekutin;
:* '''Histamine''' causes itching, endothelial dysfunction, erythema, bronchoconstriction and fluid loss;
:* '''Leukotrieny''' vedou k endoteliální dysfunkci, ke ztrátám tekutin, bronchokonstrikci či hypotenzi;
:* '''Leukotrienes''' lead to endothelial dysfunction, fluid loss, bronchoconstriction or hypotension;
:* '''Adenosin''' způsobuje bronchokonstrikci;
:* '''Adenosine''' causes bronchoconstriction;
:* '''Prostaglandin D2''' vyvolává hypotenzi;
:* '''Prostaglandin D2''' induces hypotension;
:* '''Interleukiny a TNFα''' jsou příčinou protrahované anafylaxe.
:* '''Interleukins and TNFα''' cause prolonged anaphylaxis.


== Treatment ==
== Treatment ==
=== Pre-medical first aid ===
=== Pre-medical first aid ===
Pokud je nemocný v šoku a neotékají mu horní dýchací cesty, je vhodné uložit ho do Trendelenburgovy polohy. <ref name="uptodate">{{Cite
If the patient is in shock and his upper airways are not swollen, it is advisable to place him in the Trendelenburg position. <ref name="uptodate">{{Cite
| type = db
| type = db
| responsibility = Ronna L Campbell, MD, PhD    John M Kelso, MD
| responsibility = Ronna L Campbell, MD, PhD    John M Kelso, MD
Line 103: Line 91:
| cited = 2017-07-18
| cited = 2017-07-18
}}</ref>
}}</ref>
Dále provedeme '''správný''' záklon hlavy s uvolněním dýchacích cest a v případě potřeby zahájíme kardiopulmonální resuscitaci. Pokud alergen pronikl do tkáně vpichem, lokálně končetinu chladíme. V ideálním případě, kdy má postižený u sebe balíček s léky na anafylaktickou reakci, použijeme jich dle návodu. <ref name="čls"/>
Next, we perform the '''correct''' tilting of the head with a clearing of the airways and, if necessary, initiate cardiopulmonary resuscitation. If the allergen penetrated the tissue by injection, we cool the limb locally. Ideally, if the affected person has a package with drugs for an anaphylactic reaction, we will use them according to the instructions. <ref name="čls"/>


=== Medical first aid and therapy ===
=== Medical first aid and therapy ===


====== Zajištění dýchacích cest: ======
====== Respiratory protection: ======
Při obstrukci dýchacích cest včasná intubace a oxygenace. <ref name="uptodate">{{Citace
Early intubation and oxygenation in airway obstruction. <ref name="uptodate">{{Cite
| type = db
| type = db
| responsibility = Ronna L Campbell, MD, PhD    John M Kelso, MD
| responsibility = Ronna L Campbell, MD, PhD    John M Kelso, MD
Line 116: Line 104:
| cited = 2017-07-18
| cited = 2017-07-18
}}</ref>
}}</ref>
====== Zajištění oběhu: ======
====== Circulation: ======


Důležité je zejména '''[[zajištění žilního přístupu]]''' <ref name="uptodate"/>
'''[[Ensuring venous access]]''' is particularly important. <ref name="uptodate"/>
* rychlé podávání krystaloidů a volumexpandérů;
* rapid administration of crystalloids and volume expanders;
* podání adrenalinu ''i.m.'', do m. vastus lateralis, v dávce 0,01 mg/kg (maximální dávka 0,5 mg); <ref name="uptodate"/>
* administration of adrenaline to the lateral vastus muscle at a dose of 0.01 mg / kg (the maximum dose is 0.5 mg) <ref name="uptodate"/>
** Intravenozní podávání adrenalinu je vyhrazeno pro speciální případy!
** Intravenous administration of adrenaline is reserved for special cases!
* Intravenozní podávání antihistaminik, např. Dithiaden v dávce 1 mg i.m., lépe i.v. (maximální denní dávka je 8 mg). <ref name="čls">{{Cite
* Intravenous administration of antihistamines, eg Dithiaden at a dose of 1 mg IM, or preferably iv (the maximum daily dose is 8 mg). <ref name="čls">{{Cite
| type = academic_publication
| type = academic_publication
| surname1 = Petrů
| surname1 = Petrů
Line 133: Line 121:
}}
}}
</ref>
</ref>
* Podání [[kortikosteroidy|kortikoidů]] má omezený vliv v akutní fázi, hodí se spíše pro fázi pozdější. <ref name="čls"/>
* [[Corticosteroids]] administration has a limited effect in the acute phase, so it is more suitable for the later phase. <ref name="čls"/>
* Při bronchospasmu podáváme β<sub>2</sub>-mimetika (např. Ventolin) v dávkách obvyklých jako při bronchiálním astmatu.
* In bronchospasm, we administer β<sub>2</sub>-mimetics (např. Ventolin) (eg ventolin) in the usual doses as in bronchial asthma.
* U lokálních reakcí volíme lokálně chlazení, lokální antihistaminika, ev. antihistaminika celkově p.o.
* For local reactions, we choose local cooling, local antihistamines, or general antihistamines p.o.


=== Následná péče ===
=== Aftercare ===
Pacienty s anamnézou závažné anafylaktické reakce po propuštění vybavujeme '''pohotovostním balíčkem''' pro případ opětovného styku s antigenem. Balíček by měl obsahovat '''''adrenalinové pero (Epipene), Prednison tbl. a p.o. antihistaminika'''''.
Patients with a history of severe anaphylactic reaction after discharge are provided with an '''emergency package''' in case of re-exposure to the antigen. The package should contain an '''''adrenaline pen (Epipene), Prednisone tbl. and peroral antihistamines.'''''
;Pacienta nutno sledovat 12–24&nbsp;hodin po reakci k observaci na interním či pediatrickém oddělení. <ref name="čls"/>
;The patient should be observed 12–24&nbsp;hours after the response in the internal medicine or pediatric ward. <ref name="čls"/>


<noinclude>
<noinclude>
Line 175: Line 163:
[[Category:Emergency medicine]]
[[Category:Emergency medicine]]
[[Category:Pathology]]
[[Category:Pathology]]
[[Category:Pediatrics]]
[[Category:Paediatrics]]

Latest revision as of 21:37, 13 November 2023

Anaphylactic shock is a severe circulation disorder caused by immunological mechanisms. We distinguish between severe forms (anaphylactic shock - with organ systems damage and a distributional shock) and less severe forms (mild skin conditions, urticarial reaction).

Voice changes, difficulty swallowing and dyspnoea are all signs of a severe course.

Clinical picture[edit | edit source]

The skin of a patient with anaphylaxis

The time between antigen exposure and the onset of clinical signs is usually less than one hour, the delay depends on several factors: the patient's sensitivity, the route of allergen administration and the amount of allergen. In 20% of patients, we observe a two-phase course of an anaphylactic reaction, in which the symptoms appear 6–24 hours after the initial reaction.

Skin and mucous membranes[edit | edit source]
  • Pruritus and erythematous flush.
  • Urticaria, which is mediated by IgE is usually located at the site of the allergen exposure, such as insect bites.
  • Angiooedema (more severe cases) = swelling of the lower dermis and the subcutaneous layer.
  • Angiooedema accompanied by urticaria is itchy.
  • Non-pruritic angiooedema is not a sign of hypersensitivity (eg. hereditary angiooedema).
  • Damage to mucous membranes is characterized by pruritus and congestion of the conjunctiva, nasal mucosa and oral cavity.
  • Swelling of the lips or tongue can lead to difficulty swallowing, and in severe cases to respiratory distress.
Respiratory system[edit | edit source]

In the upper respiratory tract, there is life-threatening oedema of the larynx and / or the epiglottis and other adjacent structures.

  • Clinically, children may report a feeling of discomfort in the throat, difficult speech, and hoarseness of voice.
  • Inspiratory stridor may appear.

Lower airway involvement resembles an asthma attack with expiratory dyspnea, cough and chest retractions.

Cardiovascular system[edit | edit source]

Anaphylactic shock is a type of distributional shock. The cause of hypotension is extreme vasodilation, increased vascular permeability, and capillary leak syndrome.

The result is an intravascular volume depletion, and a toxic effect of released mediators cannot be ruled out pathophysiologically.

Clinically, we find a patient with hypotension, difficult-to-palpate pulsations, tachycardia, but pink periphery. We can often observe arrhythmia, the ECG may show signs of myocardial ischemia.

Central nervous system[edit | edit source]

Dizziness, syncope, convulsions or alterations of consciousness may appear. Clinical signs are caused by both hypoperfusion and CNS hypoxia and the direct toxic effect of released mediators.

Gastrointestinal system[edit | edit source]

Damage includes nausea, vomiting, diarrhoea and abdominal pain. Other symptoms include rhinorrhoea, profuse sweating, metallic taste in the mouth, feeling hot, skin burning or a feeling of danger.

Severe forms[edit | edit source]

Death occurs in the first hour after the reaction!

Severe forms occur immediately within minutes of allergen exposure (after drug application, after insect stings).

Symptoms:

  • General: nausea, chills, palmar and plantar pruritus, pallor, loss of consciousness, hypothermia, bronchospasm, laryngeal oedema, vomiting, diarrhoea;
  • Breathing: rapid, shallow, wheezing;
  • Cardiovascular: tachycardia, hypotension, intangible pulse, inaudible sounds, convulsions,
ECG changes: atrial fibrillation, ST changes.

Laboratory examination:

Hemoconcentration, leucopenia, thrombocytopenia, hypoxemia, hypocapnia, later hypercapnia and acidosis with metabolic predominance also appear. Coagulation disorders in the form of DIC may occur.


Less severe forms[edit | edit source]

Less severe forms are characterized by generalized erythema and oedema, including pharyngeal oedema. Symptoms:

  • bronchospasm, irritating cough, dyspnoea.

Diagnosis[edit | edit source]

The clinical picture and the determination of the etiological agent are crucial.

We determine total and specific IgE and perform skin tests (prick tests). Elevation of eosinophilic cationic protein (ECP), an increase of histamine in both plasma and urine, and detection of eosinophils in bronchial or nasal secretion indicate an allergic cause. Tryptase, a specific mast cell protease, is determined experimentally.

Differential diagnosis[edit | edit source]

Vasovagal syncope is characterized by a response to pain or stress. We find cold acres, nausea, and a feeling of fainting, on the other hand, we do not see any skin marks or signs of airway obstruction. Bradycardia is typical, while anaphylaxis induces tachycardia as a compensatory mechanism. Pruritus is not present in hereditary angiooedema, in the family history we often find data on oedema or suffocation. We confirm the diagnosis with decreased levels of C1 complement inhibitor and decreased CH 50 complement activity. Arrhythmia is shown in the ECG. In patients, with a hysterical attack, we can sometimes also find symptoms of an anaphylactic reaction. Here, a psychiatric-psychological examination is necessary for a correct diagnosis.

Mechanism[edit | edit source]

An anaphylactic reaction is a life-threatening process in which the body reacts excessively to contact with an allergen. It is therefore a special type of allergic reaction. Contact with an allergen activates the immune system. Activation of inflammatory factors increases vascular permeability and mass transfer of intravascular fluid into the interstitium. This reduces the volume of intravascular body fluid, which leads to hypotension and the patient falls into shock.

The anaphylactic reaction is triggered by three well-known mechanisms of the immune response to foreign substance exposure.

IgE mediated reaction[edit | edit source]

It represents up to 60% of all anaphylactic reactions. IgE antibodies can be formed after a patient's first encounter with a foreign antigen. The antigen may be presented alone or in association with a protein carrier. IgE binds to mast cell and basophil receptors. Upon re-exposure to antigen → antigen leads to the bridging of IgE molecules → degranulation of these cells and release of various fast-acting mediators.

Complement mediated reaction[edit | edit source]

Immunocomplex-activated complement cascade. The result is the formation of anaphylatoxins such as C3a and C5a - the direct mechanism that triggers the release of mediators from basophils and mast cells. Immunocomplex activated complement is the reaction to [transfusion of blood|blood transfusion]], blood derivatives or plasma. Complement-mediated anaphylaxis occurs, for example, in patients with IgA deficiency. The formation of IgG anti-IgA antibodies has been demonstrated in these patients. The complement can also be activated directly by contrast agents and the dialysis membrane.

Direct release of mediators and other mechanisms[edit | edit source]

  • The mechanism of a direct mediator release, without the involvement of IgE or complement, is still unknown. Substances capable of this reaction are, for example, hyperosmolar substances such as mannitol, radiocontrast substances, opiates, quinolones or vancomycin.
  • Anaphylaxis after the administration of non-steroidal anti-inflammatory drugs (NSAID) is associated with the blockade of prostaglandin synthesis caused by NSADs, leukotriene production increases and anaphylaxis is triggered.
  • Exercise or cold-induced anaphylaxis is based on the principle of direct histaminoliberation or IgE mediated reactions.

The effect of mediators[edit | edit source]

  • Release of mediators in degranulation – histamine, tryptase, heparin.
  • Many mediators of anaphylaxis are formed by de novo synthesis – prostaglandins D2, leukotrienes, PAF, IL-4, 5, 6, 13, TNFα and adenosine.

Mediators → development of clinical signs of anaphylactic reaction: bronchospasm, increased capillary permeability, alterations of systemic and pulmonary vascular smooth muscle.

  • Histamine causes itching, endothelial dysfunction, erythema, bronchoconstriction and fluid loss;
  • Leukotrienes lead to endothelial dysfunction, fluid loss, bronchoconstriction or hypotension;
  • Adenosine causes bronchoconstriction;
  • Prostaglandin D2 induces hypotension;
  • Interleukins and TNFα cause prolonged anaphylaxis.

Treatment[edit | edit source]

Pre-medical first aid[edit | edit source]

If the patient is in shock and his upper airways are not swollen, it is advisable to place him in the Trendelenburg position. [1] Next, we perform the correct tilting of the head with a clearing of the airways and, if necessary, initiate cardiopulmonary resuscitation. If the allergen penetrated the tissue by injection, we cool the limb locally. Ideally, if the affected person has a package with drugs for an anaphylactic reaction, we will use them according to the instructions. [2]

Medical first aid and therapy[edit | edit source]

Respiratory protection:[edit | edit source]

Early intubation and oxygenation in airway obstruction. [1]

Circulation:[edit | edit source]

Ensuring venous access is particularly important. [1]

  • rapid administration of crystalloids and volume expanders;
  • administration of adrenaline to the lateral vastus muscle at a dose of 0.01 mg / kg (the maximum dose is 0.5 mg) [1]
    • Intravenous administration of adrenaline is reserved for special cases!
  • Intravenous administration of antihistamines, eg Dithiaden at a dose of 1 mg IM, or preferably iv (the maximum daily dose is 8 mg). [2]
  • Corticosteroids administration has a limited effect in the acute phase, so it is more suitable for the later phase. [2]
  • In bronchospasm, we administer β2-mimetics (např. Ventolin) (eg ventolin) in the usual doses as in bronchial asthma.
  • For local reactions, we choose local cooling, local antihistamines, or general antihistamines p.o.

Aftercare[edit | edit source]

Patients with a history of severe anaphylactic reaction after discharge are provided with an emergency package in case of re-exposure to the antigen. The package should contain an adrenaline pen (Epipene), Prednisone tbl. and peroral antihistamines.

The patient should be observed 12–24 hours after the response in the internal medicine or pediatric ward. [2]


References[edit | edit source]

Related articles[edit | edit source]

External links[edit | edit source]

References[edit | edit source]

  1. ↑ Jump up to: a b c d Anaphylaxis: Emergency treatment [database]. Ronna L Campbell, MD, PhD John M Kelso, MD. The last revision 2017-04-03, [cit. 2017-07-18]. <https://www.uptodate.com/contents/anaphylaxis-emergency-treatment>.
  2. ↑ Jump up to: a b c d PETRŮ, Vít. Anafylaktické reakce [online]. Praha : ČLS JEP, 2001, Available from <http://www.cls.cz/dokumenty2/postupy/r003.rtf>. 

Literature[edit | edit source]

  • HOŘEJŠÍ, Václav – BARTŮŇKOVÁ, Jiřina. Základy imunologie. 3. edition. Praha : Triton, 2008. 280 pp. ISBN 80-7254-686-4.
  • HAVRÁNEK, Jiří: Anafylaxe

Template:Pahýl

Retrieved from "https://www.wikilectures.eu/index.php?title=Anaphylaxis&oldid=89271"