From the Guidelines
Diagnosis of Horner syndrome requires a systematic approach focusing on clinical examination and pharmacological testing, prioritizing the identification of the classic triad of symptoms: ptosis, miosis, and anhidrosis, as outlined in the most recent guidelines 1. The diagnosis begins with identifying these symptoms on the affected side of the face. Initial evaluation should include a detailed history to identify potential causes such as stroke, neck trauma, lung cancer (Pancoast tumor), or carotid artery dissection.
- Key components of the examination include:
- Complete ophthalmic examination with emphasis on sensorimotor evaluation
- Careful check for other neuro-ophthalmic signs and symptoms
- Fundus examination to check for papilledema or optic atrophy
- Visual field testing to provide additional information on the etiology Physical examination should assess for anisocoria, which is typically more pronounced in dim light, and confirm that the ptosis involves both the upper lid and the lower lid.
- Pharmacological testing is essential for confirmation and localization of the lesion, using tests such as the cocaine test or hydroxyamphetamine 1% to determine the location of the lesion 1. Once diagnosed, imaging studies such as MRI of the brain and neck, chest CT, or carotid angiography may be necessary to identify the underlying cause, as Horner syndrome can be the first sign of serious conditions like carotid dissection or apical lung cancer, requiring immediate intervention 1.
From the Research
Diagnostic Criteria for Horner Syndrome
The diagnostic criteria for Horner syndrome include:
- Unilateral ptosis (drooping eyelid) 2, 3, 4, 5
- Ipsilateral miosis (constricted pupil) 2, 3, 4, 5
- Ipsilateral facial anhidrosis (reduced sweating) in some cases 2, 3, 4
Clinical Presentation
The clinical presentation of Horner syndrome can vary, and patients may not always present with the classic triad of ptosis, miosis, and anhidrosis 6. The onset of anisocoria (unequal pupil size) may be uncertain, and many cases are referred after incidental discovery on routine optometric assessment 6.
Pharmacologic Testing
Pharmacologic testing can be used to confirm the diagnosis of Horner syndrome, including:
Imaging Modalities
Modern imaging modalities, such as MRI and CT scans, can be used to help diagnose and localize the underlying pathology causing Horner syndrome 6, 4, 5.