Angioedema in ICU

 

Angioedema is a medical emergency. 

Based on the mechanism, Angioedema may be classified as-

 

• Histamine related Angioedema

• Bradykinin related angioedema

 

Histamine related Angioedema is similar to the spectrum of full blown anaphylaxis. The treatment of histamine mediated angioedema is much similar to anaphylaxis.

 

Bradykinin related angioedoema differs from the above by its mechanism and the appropriate treatment. There are various types of Bradykinin mediated Angioedema (Please see table 2)

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History:

Prior personal history and positive family history may point strongly towards Hereditary Angioedema

Medications history i.e ACE-I inhibitor may suggest alternative diagnosis.

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Differential Diagnosis

• Infection (e.g. deep neck space infection)

• Functional or factitious stridor

• Foreign body

• Superior vena cava syndrome

• Macroglossia (e.g. due to acromegaly, amyloid, or hypothyroidism)

 

 

 

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Diagnosis

Lab values to sent:

 

• Complement level

• C1-Inhibitor (C1-INH) level

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Management:- 

 

Please follow the flow chart.

 

Indication for intubation

 

• Stridor, dyspnoea, muffled or hoarse voice.

• Drooling and inability to handle secretions.

• Progressive deterioration of oedema to cause any of the above 

• Nasolaryngoscopy shows significant laryngeal oedema or impending closure of the posterior pharynx

 

Role of Nasolaryngoscopy: 

 

• Delineate whether there is significant laryngeal edema.

• Rule out other causes of airway obstruction or edema

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Mechanism of action 

 

Tranexamic acid:

• Inhibits the conversion of plasminogen into plasmin (critical step involved in amplification of kallikrein activation)

• Effective in of bradykinin-mediated angioedema

 

C1-inhibitor concentrate:

• Inhibits XIIa and kallikrein (two most important enzymes involved in bradykinin generation)

 

Fresh Frozen Plasma:

FFP replaces:

• Angiotensin converting enzyme (ACE) [ACEi-induced angioedema]

• C1-inhibitor [hereditary angioedema has deficient C1-inhibitor activity]

 

Bradykinin Antagonist (Icatibant) and Kallkrein inhibitor (Ecallantide)

 

• No robust evidence for use of the above 

• Not widely available and very expensive (they are often even harder to obtain than C1-esterase inhibitor concentrate)

• For Subcutaneous administration which may not be useful in an acute setting

• Icatibant- Found to be ineffective in ACE inhibitor induced angioedema

• Ecallantide also was not found to be very effective and caries a 3% risk on anaphylaxis.

 

Airway management

 

• Anticipate difficult airway.

• The swelling may get worse with airway manipulation.

• If there is laryngeal edma, laryngeal mask airway may become ineffective.

• May need surgical airway in the first go as orotracheal intubation may be impossible

Procedure:

• Awake fibreoptic intubation Vs Awake cricothyroidectomy

• Non-respiratory depressant agents for induction: Ketamine, Dexmedetomidine

• Preoxygenation 

• Backup for front of neck approach

• Experienced operator

• Surgical expertise- (ENT) as back up

 

Extubation

Consideration: -

• Severity of swelling to start with

• External features- visible swelling, tongue swelling

• Videolaryngoscopic view vs nasal endoscopy prior to attempt for extubation

• Cuff leak test

• Extubation in operating theatre Vs in ICU

• Extubation over an exchange catheter