Hives/angioedema/Anaphylaxis Flashcards
Explain Hives (urticaria)? The diagnositic studies and the therapy?
- A localized non-pitting edema, involves only the superficial portion of the dermis
- Characterized by the rapid appearance of well-circumscribed welts, a superficial, itchy swelling of the skin (hive)
- Rapid onset and self-limiting
- Urticarial crops appear in various stages of evolution
- The primary effector cell is the cutaneous mast cell which release histamine and other inflammatory mediators
Diagnostic studies: CBC with differential, ESR or CRP, TSH
Therapy: Non-sedating antihistamines. If no response, add an H2 blocker (example: Cimetidine) and short-term oral corticosteroids
explain angioedema? Diagnostic studies?
- A severe, potentially life-threatening disorder characterized by recurrent episodes of severe swelling under the skin
- Angioedema differs from urticaria in that it covers a larger skin surface area and involves both the dermis and subcutaneous tissues
- Angioedema without urticaria should raise suspicion for hereditary angioedema (HAE)
Diagnostic studies: C2, C4, and C1 esterase inhibitor levels (functional and antigenic) to rule out HAE. C2 levels are low in acute HAE and C4 levels are low in both acute episodes and in remission. C4 and C1 esterase levels are normal in other forms of angioedema
Therapy for angioedema?
Therapy:
- Antihistamines and corticosteroids for cases without airway compromise or hemodynamic instability
- With acute episodes of compromise or hypotension, use epinephrine (racemic nebulized form or IM injections), antihistamines, and corticosteroids
*****It is important to note that MOST cases of angioedema are NOT HAE or C1 inhibitor deficiency
Explain hereditary angioedema?
- A rare genetic autosomal dominant disease involving C1 esterase inhibitor and very rarely due to a mutation of the Factor XII gene
- Potentially life-threatening recurrent attacks of severe swelling. Typically, itchiness does not occur
- Most common areas of the body to develop swelling are the limbs, face, intestinal tract, and airway
- Consider HAE in individuals with: Recurrent angioedema without urticaria Laryngeal edema Recurrent episodes of abdominal pain and vomiting A positive family history
Explain hereditary angioedema?
I. 85% of patients have low quantitative levels of C1 inhibitor
II. 15% of patients have normal or elevated levels of C1 inhibitor but the protein doesn’t function properly.
III. Angioedema due to a mutation of the Factor XII gene. These patients have normal C1 esterase inhibitor levels and function
Acute treatment of hereditary angioedema?
Acute: Halt the progression of edema as quickly as possible
- Replacement therapy C1 inhibitor concentrate from donor blood or in emergency situation where this isn’t available give Fresh Frozen Plasma
- C1 Inhibitor treatments Ecallantide (Kalbitor): inhibitor of the protein Kallikrein Icatibant: inhibits the bradykinin B2 receptor Berinert: C1 inhibitor (human) pasteurized adds functioning C1 inhibitor directly to the blood stream
Prophylaxis of hereditary angioedema?
Prophylaxis: Specific stimuli that have led to attack should be avoided
- Lanadelumab: human monoclonal antibody that inhibits plasma Kallikrein 1st drug approved for prevention
- Cinryze: complement C1 esterase inhibitors, nano-filtered for IV injection for prophylaxis
- Ruconest: a plasma-free recombinant C1 esterase inhibitor for IV injection
Hereditary angioedema does not respond to?
Hereditary angioedema does not respond to antihistamines, corticosteroids, or epinephrine
HAE prognosis?
It is estimated that 25% to 30% of identified HAE patients die in the first two decades of life, mainly due to lack of treatment.
Epidimiology of Hereditary angioedema?
Data is limited. The incidence of HAE is one on 10,000-50,000 people in the U.S. and Canada. Mortality rates are estimated at 15-33%, resulting primarily from laryngeal edema and asphyxiation. HAE leads to 15,000 to 30,000 emergency department visits per year
hereditary angioedema synopsis?
What is anaphylaxis?
- A systemic life-threatening disorder that can evolve rapidly
- A medical emergency
- A clinical diagnosis – treat, don’t wait for diagnostic lab tests
- Caused by mediators released from mast cells and basophils in an individual sensitized to a given antigen
- Early recognition of an anaphylactic reaction is crucial since death can occur within minutes to hours after the onset of the first symptoms
Criteria for the diagnosis of anaphylaxis?
Types of anaphylaxis?
Mechanism Mediating Mediator Release by Mast Cells and Basophils
• When IgE activated: “Immunologic”
• When direct activation of these cells: “Non-Immunologic”
Patterns of anaphylaxis?
- Uniphasic: 70%-90% of patients Peaks in 30-60 minutes – resolves over the next hour No recurrence of symptoms
- Biphasic: 3% of adults and up to 15% of child patients Recurrence of symptoms hours after resolution of initial event
- Protracted/Persistent: Symptoms last days to weeks
