Investigations

1st investigations to order

laryngoscopy

Test
Result
Test

Direct (rigid or flexible) laryngoscopy can be performed. It is the key to confirming diagnosis, but is also therapeutic, as an airway can be established in the same setting if a direct laryngoscopy commences. This should be performed in the operating theatre, as an emergency surgical airway can be obtained if endotracheal intubation is not possible.

Result

swelling of supraglottic structures

erect lateral neck radiograph

Test
Result
Test

Classically referred to as a high-kilovoltage lateral neck radiograph.

Only to be obtained with healthcare professionals capable of securing the airway with proper equipment available during the test. The patient should be kept in an upright position. The child should not be sent to the radiology department unaccompanied for this examination. Also, the patient should not be perturbed (especially children). It is usually safe to perform this test in adults who are not in extremis.[Figure caption and citation for the preceding image starts]: Lateral neck film demonstrating thumbprint sign (arrows)From the collection of Dr Petri [Citation ends].com.bmj.content.model.Caption@30e71b05

Result

markedly enlarged epiglottis, referred to as a 'thumbprint sign'

Investigations to consider

full blood count

Test
Result
Test
Result

leukocytosis with left shift is possible

cultures of blood/supraglottis (epiglottis)

Test
Result
Test

Blood cultures and cultures from the supraglottis or epiglottis are critical in identifying the infecting organism, but should only be taken if possible and permissible without perturbing the patient and/or once the airway has been secured.

Result

positive cultures

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