Tests

1st tests to order

laryngoscopy

Test
Result
Test

Mainstay of diagnosis.

Can be performed by the use of a rigid or flexible laryngoscope.

Performed if the patient presents initially to an otolaryngology specialist, but most primary care physicians are not experienced in the technique and diagnose most cases of viral laryngitis clinically.

Some primary care physicians may use mirror indirect laryngoscopy, depending on experience.

Result

acute infectious laryngitis: edema and erythema of the true vocal folds; thick, copious, white-yellow secretions in the glottis; chronic tuberculous laryngitis: exophytic or nodular laryngeal lesions commonly involving the posterior glottis; reflux laryngitis: no exudative changes in the larynx, may show hyperemia of the arytenoids and the posterior true vocal folds

Investigations to avoid

computed tomography (CT)

Recommendations
Rationale
Recommendations

Do not obtain CT scans before laryngoscopy is performed. Further imaging is only indicated to evaluate vocal fold paralysis or a mass or lesion of the larynx.​[22][25]

Rationale

CT scans are not necessary in most patients with dysphonia because this is usually self-limiting or caused by pathology that can be identified by laryngoscopy alone. This avoids unnecessary testing, radiation and overdiagnosis while minimizing cost and adverse events.​[22][25]

magnetic resonance imaging (MRI)

Recommendations
Rationale
Recommendations

Do not obtain MRI before laryngoscopy is performed. Further imaging is only indicated to evaluate vocal fold paralysis or a mass or lesion of the larynx.​[22][25]

Rationale

MRI is not necessary in most patients with dysphonia because this is usually self-limiting or caused by pathology that can be identified by laryngoscopy alone. This avoids unnecessary testing, radiation and overdiagnosis while minimizing cost and adverse events.​[22][25]

viral panel testing

Recommendations
Rationale
Recommendations

Do not order comprehensive viral panel tests for children who present with typical signs and symptoms of laryngitis.[24]

Rationale

There is a lack of consistent evidence to demonstrate the impact of comprehensive viral panel test results on clinical outcomes or management.[24]

Tests to consider

biopsy

Test
Result
Test

Biopsies should be obtained in cases where tuberculosis is suspected.

Procedure is usually performed with a general anesthetic.

Result

chronic tuberculous laryngitis: granulomatous necrosis, positive stain for acid-fast bacilli

oropharyngeal cultures

Test
Result
Test

Cultures should be obtained if bacterial infection, diphtheria, or tuberculosis are suspected.

Loeffler or Tindale selective media are used when diphtheria is suspected.[26]

Result

positive cultures in bacterial infection

nasal swab for culture

Test
Result
Test

Cultures should be obtained if diphtheria is suspected.

Loeffler or Tindale selective media are used when diphtheria is suspected.[26]

Result

positive cultures in bacterial infection

serum immunoprecipitation or polymerase chain reaction for diphtheria

Test
Result
Test

Definitive diagnosis of diphtheria can also be made by the demonstration of toxin production.

Result

positive in diphtheria

complete blood count

Test
Result
Test

May be performed if acute bacterial infection is suspected.

Result

may be a leukocytosis with left shift in bacterial infection

rapid antigen detection test

Test
Result
Test

May be performed if bacterial laryngitis due to group A streptococcal infection is suspected.

Result

positive in bacterial infection

chest x-ray

Test
Result
Test

Should be obtained in cases where tuberculosis is suspected.

Result

cavitary lesions in tuberculosis

sputum cultures

Test
Result
Test

Performed routinely in patients with suspected tuberculosis.

Result

may be positive for mycobacteria in cases of tuberculosis

videostroboscopy

Test
Result
Test

Hoarseness is not always due to laryngitis, and therefore careful exam using videostroboscopy to evaluate the vocal folds and rule out a more serious vocal fold injury (hemorrhage or vocal mucosal tear) in heavy voice users is essential.

Videostroboscopy allows for simultaneous evaluation of voice quality, laryngeal anatomy, and vocal fold vibratory function.[23]

Guidelines on dysphonia encourage the use of videostroboscopic examination when the voice symptoms are out of proportion to the indirect laryngoscopy.[22]

Result

reveals vocal fold sulcus or vibratory pathologies such as stiffness, or helps differentiate between benign vocal lesions

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