Ptosis and Horner syndrome

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38 Ptosis and Horner syndrome

Instruction

Examine this patient’s face.

Salient features

History

• Ask the patient whether or not there is absence of sweating on one side of the face

• History of lung cancer

• History of cervical sympathectomy

Examination

In the examination if you notice ptosis then you must answer the following questions:

• Is ptosis complete or incomplete?

• Is it unilateral or bilateral?

• Is the pupil constricted (Horner syndrome) or dilated (third nerve palsy)?

• Are extraocular movements involved (third nerve palsy or myasthenia gravis)?

• Is the eyeball sunken or not (enophthalmos)?

• Is the light reflex intact (intact light reflex in Horner syndrome)?

If the patient has Horner syndrome, then quickly proceed as follows:

These should help in making a diagnosis of syringomyelia or Pancoast’s tumour.

If there is no clue so far about the cause, tell the examiner that you would like to examine for nystagmus, cerebellar signs, cranial nerves and pale optic discs, and pyramidal signs to ascertain brainstem vascular disease or demyelination.

Diagnosis

This patient has Horner syndrome (lesion) associated with dullness in the supraclavicular area indicating a Pancoast’s tumour (aetiology).

Questions

What causes Horner syndrome?

The syndrome is caused by the involvement of the sympathetic pathway. It starts in the sympathetic nucleus and travels through the brainstem and spinal cord to the level of C8/T1/T2 to the sympathetic chain, stellate ganglion and carotid sympathetic plexus (Am J Ophthalmol 1958;46:289–96)). Its significance requires an understanding of the oculosympathetic pathway 3-neuron chain. The first-order nerve (FON) fibres descend from the hypothalamus without decussation to the thoracic spinal cord before synapsing with the second-order neurons (SON). The SONs exit the spine at the C8, T1 and T2 levels to enter the sympathetic chain and travel over the pleural cap of the lung and loop around the subclavian artery before synapsing near the carotid bifurcation. The final third-order neurons (TON) travel along the internal carotid artery to innervate the eyelids and the eye and also along the external carotid artery to innervate facial sweat glands.

What are the features of Horner syndrome?

It is characterized by:

• miosis (resulting from paralysis of the dilator of the pupil) (Fig. 38.1)

• partial ptosis or pseudo-ptosis (caused by paralysis of the upper tarsal muscle)

• enophthalmos (caused by paralysis of the muscle of Müller)

• often, slight elevation of the lower lid (because of paralysis of lower tarsal muscles).

Fig. 38.1 Horner syndrome affecting the left eye. (A) Mild upper lid ptosis and miosis in room light. (B) Anisocoria is increased at 5 s after the lights are dimmed as a result of dilation lag of the left pupil. (C) At 15 s after the lights are dimmed, the left pupil has increased dilation compared to that at 5 s (B).

What additional feature would you see in congenital Horner syndrome?

There would be heterochromia of the iris: the iris remains grey–blue.

How would you determine the level of lesion using only history?

The level of the lesion is determined by the distribution of the loss of sweating:

• Central lesion: sweating over the entire half of the head, arm and upper trunk is lost.

• Lesions of the neck:

• Proximal to the superior cervical ganglion: diminished sweating on the face

• Distal to the superior cervical ganglion: sweating is not affected.

Advanced-level questions

How would you differentiate whether the lesion is above the superior ganglion (peripheral) or below the superior cervical ganglion (central)?

Test	Above	Below
Sweating	Such lesions may not affect sweating at all as the main outflow to the facial blood vessels is below the superior cervical ganglion	Such lesions affect sweating over the entire, head, neck and arm upper trunk Lesions in the lower neck affect sweating over the entire face
Cocaine 4% in both eyes	Dilates the normal pupil, no effect on the affected side	Dilates both pupils
Epinephrine (adrenaline, 1:1000) in both eyes	Dilates affected eye, no effect on normal side	No effect on both sides

Note: In peripheral lesions there is depletion of amine oxidase as a result of postganglionic denervation. As a result, this sensitizes the pupil to 1 : 1000 epinephrine (adrenaline), whereas it has no effect on the normal pupil or in central lesions (where the presence of the enzyme rapidly destroys the epinephrine).

Mention one cause of intermittent Horner syndrome

If the patient has Pancoast’s tumour, what is the most likely underlying pathology?

Squamous cell carcinoma.

JF Horner (1831–1886), Professor of Ophthalmology in Zurich, conceded that Claude Bernard had recognized the syndrome before him.

Henry K Pancoast (1875–1939) was the first Professor of Radiology in the USA at the University of Pennsylvania.

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