- ↓ Renal perfusion → Renin release from the kidneys.
- Renin converts angiotensinogen → Angiotensin I, which is then
converted to Angiotensin II.
1. Renin-Angiotensin-Aldosterone - Angiotensin II causes:
System (RAAS) Activation --> Vasoconstriction → increases systemic vascular resistance (SVR) and
blood pressure.
--> Aldosterone release from adrenal cortex → promotes sodium and
water retention, increasing blood volume and cardiac output.
- Decreased stretch in baroreceptors (aortic arch and carotid sinuses) →
stimulates SNS response.
2. Sympathetic Nervous System - SNS causes vasoconstriction of arterioles (especially after the aorta),
(SNS) Activation which increases peripheral resistance.
- Also increases heart rate (HR) and contractility, helping maintain
cardiac output.
- Hypothalamic osmoreceptors sense low blood volume or increased
plasma osmolality.
3. Hypothalamic-Pituitary Response - This stimulates the posterior pituitary gland to release antidiuretic
(ADH Mechanism) hormone (ADH).
- ADH increases water reabsorption in the kidneys → expanding
intravascular volume.
• Anaphylaxis is an acute, potentially life-threatening, multisystem
syndrome caused by the sudden release of mast cell mediators into the
Anaphylactic Shock systemic circulation.
• Sudden onset with rapid progression to death within minutes
, Rapid progression of symptoms, evidence of:
- Respiratory distress (e.g., stridor, wheezing, dyspnea, increased work
of breathing, retractions, persistent cough, cyanosis)
- Signs of poor perfusion
Anaphylactic Shock: Danger Signs: - Abdominal pain
- Vomiting
- Dysrhythmia
- Hypotension
- Collapse.
It most often results from immunoglobulin E (IgE)-mediated reactions to:
Anaphylactic Shock •Foods (most common children)
•Medications (most common adults)
Etiology? •Insect stings (most common adults)
•Any agent
- Airway
- IM Epinephrine
- O2 Therapy
Anaphylactic Shock: Management: - Normal Saline (0.9% Bolus)
- Albuterol (Salbutamol)
- Histamine Blockers
- Glucocorticoid
Anaphylactic Shock: Management: - Immediate intubation if evidence of impending airway obstruction
from angioedema.
Airway: - Delay may lead to complete obstruction.
,Anaphylactic Shock: Management: - For bronchospasm resistant to IM epinephrine.
Albuterol (Salbutamol):
Anaphylactic Shock: Management: - The first and most important treatment in anaphylaxis is Epinephrine.
- There are NO absolute contraindications to epinephrine in the setting
First Step? of anaphylaxis
Anaphylactic Shock: Management: Methylprednisolone 125 mg IV.
Glucocorticoid:
- H1 Blocker: Diphenhydramine (Benadryl) - relieves itching, hives, and
Anaphylactic Shock: Management: skin flushing.
Histamine Blockers: - H2 Blocker: Ranitidine - helps reduce histamine-related vasodilation
and GI symptoms.
Anaphylactic Shock: Management: - Treat hypotension with 1 to 2 Ls of Normal Saline.
- Repeat, as needed.
Normal Saline 0.9% Bolus? - Massive fluid shifts with severe loss of intravascular volume can occur.
Anaphylactic Shock: Management: - IM Epinephrine (1 mg/mL preparation): Give epinephrine 0.3 to 0.5 mg
IM.
Promptly and Simultaneously, Give: - Can repeat every 5 to 15 minutes (or more frequently), as needed.
, - Light-headedness or dizziness
- Confusion or disorientation
Anaphylactic Shock:
- Anxiety or sense of impending doom
- Headache
Signs & Symptoms: CNS
- Loss of consciousness (in severe cases)
- Due to decreased cerebral perfusion and hypoxia.
- Tachycardia or bradycardia (fast or slow HR)
- Hypotension (low BP) due to vasodilation and fluid leakage
Anaphylactic Shock:
- Dizziness, syncope, or cardiac arrest in severe cases
Signs & Symptoms: CV System
**❤️ Cardiovascular collapse is the leading cause of death in
anaphylaxis.
- Crampy abdominal pain
- Diarrhea
Anaphylactic Shock: - Vomiting
- Pelvic pain
Signs & Symptoms: GI System - Loss of bladder control (incontinence)
**🍽️ Due to smooth muscle contraction and increased GI motility.
- Renin converts angiotensinogen → Angiotensin I, which is then
converted to Angiotensin II.
1. Renin-Angiotensin-Aldosterone - Angiotensin II causes:
System (RAAS) Activation --> Vasoconstriction → increases systemic vascular resistance (SVR) and
blood pressure.
--> Aldosterone release from adrenal cortex → promotes sodium and
water retention, increasing blood volume and cardiac output.
- Decreased stretch in baroreceptors (aortic arch and carotid sinuses) →
stimulates SNS response.
2. Sympathetic Nervous System - SNS causes vasoconstriction of arterioles (especially after the aorta),
(SNS) Activation which increases peripheral resistance.
- Also increases heart rate (HR) and contractility, helping maintain
cardiac output.
- Hypothalamic osmoreceptors sense low blood volume or increased
plasma osmolality.
3. Hypothalamic-Pituitary Response - This stimulates the posterior pituitary gland to release antidiuretic
(ADH Mechanism) hormone (ADH).
- ADH increases water reabsorption in the kidneys → expanding
intravascular volume.
• Anaphylaxis is an acute, potentially life-threatening, multisystem
syndrome caused by the sudden release of mast cell mediators into the
Anaphylactic Shock systemic circulation.
• Sudden onset with rapid progression to death within minutes
, Rapid progression of symptoms, evidence of:
- Respiratory distress (e.g., stridor, wheezing, dyspnea, increased work
of breathing, retractions, persistent cough, cyanosis)
- Signs of poor perfusion
Anaphylactic Shock: Danger Signs: - Abdominal pain
- Vomiting
- Dysrhythmia
- Hypotension
- Collapse.
It most often results from immunoglobulin E (IgE)-mediated reactions to:
Anaphylactic Shock •Foods (most common children)
•Medications (most common adults)
Etiology? •Insect stings (most common adults)
•Any agent
- Airway
- IM Epinephrine
- O2 Therapy
Anaphylactic Shock: Management: - Normal Saline (0.9% Bolus)
- Albuterol (Salbutamol)
- Histamine Blockers
- Glucocorticoid
Anaphylactic Shock: Management: - Immediate intubation if evidence of impending airway obstruction
from angioedema.
Airway: - Delay may lead to complete obstruction.
,Anaphylactic Shock: Management: - For bronchospasm resistant to IM epinephrine.
Albuterol (Salbutamol):
Anaphylactic Shock: Management: - The first and most important treatment in anaphylaxis is Epinephrine.
- There are NO absolute contraindications to epinephrine in the setting
First Step? of anaphylaxis
Anaphylactic Shock: Management: Methylprednisolone 125 mg IV.
Glucocorticoid:
- H1 Blocker: Diphenhydramine (Benadryl) - relieves itching, hives, and
Anaphylactic Shock: Management: skin flushing.
Histamine Blockers: - H2 Blocker: Ranitidine - helps reduce histamine-related vasodilation
and GI symptoms.
Anaphylactic Shock: Management: - Treat hypotension with 1 to 2 Ls of Normal Saline.
- Repeat, as needed.
Normal Saline 0.9% Bolus? - Massive fluid shifts with severe loss of intravascular volume can occur.
Anaphylactic Shock: Management: - IM Epinephrine (1 mg/mL preparation): Give epinephrine 0.3 to 0.5 mg
IM.
Promptly and Simultaneously, Give: - Can repeat every 5 to 15 minutes (or more frequently), as needed.
, - Light-headedness or dizziness
- Confusion or disorientation
Anaphylactic Shock:
- Anxiety or sense of impending doom
- Headache
Signs & Symptoms: CNS
- Loss of consciousness (in severe cases)
- Due to decreased cerebral perfusion and hypoxia.
- Tachycardia or bradycardia (fast or slow HR)
- Hypotension (low BP) due to vasodilation and fluid leakage
Anaphylactic Shock:
- Dizziness, syncope, or cardiac arrest in severe cases
Signs & Symptoms: CV System
**❤️ Cardiovascular collapse is the leading cause of death in
anaphylaxis.
- Crampy abdominal pain
- Diarrhea
Anaphylactic Shock: - Vomiting
- Pelvic pain
Signs & Symptoms: GI System - Loss of bladder control (incontinence)
**🍽️ Due to smooth muscle contraction and increased GI motility.
