Horner’s syndrome. All true exceptaEUR’
Correct Answer: Apparent exophthalmos
Description: Apparent exophthalmoses [Ref: Adams victor principles of neurology 8/e p. 2541 Horner's syndrome is a classic neurologic syndrome whose signs include: -- Miosis, - Ptosis, and - Anhidrosis Also called oculosympathetic paresis, a Horner's syndrome can be produced by a lesion anywhere along the sympathetic pathway that supplies the head, eye, and neck. Neuroanatomy Horner's syndrome can result from a lesion anywhere along a three-neuron sympathetic (adrenergic) pathway that originates in the hypothalamus - The first-order neuron - Descends caudally from the hypothalamus to the first synapse, which is located in the cervical spinal cord (levels C8-12, also called ciliospinal center of Budge). - The second-order neuron - Travels .from the sympathetic trunk, through the brachial plexus, over the lung apex. It then ascends to the superior cervical ganglion, located near the angle of the mandible and the bifurcation of the common carotid aery. - The third-order neuron - Then ascends within the adventitia of the internal carotid aery, through the cavernous sinus, where it is in close relation to the sixth cranial nerve. The oculosympathetic pathway then joins the ophthalmic (VI) division of the ,fifth cranial nerve (trigeminal nerve). In the orbit and the eye, the oculosympathetic fibers innervate the iris dilator muscle as well as Muller's muscle, a small smooth muscle in the eyelids responsible for a minor poion of the upper lid elevation and lower lid retraction. Clinical features The classic signs of a Horner's syndrome are: ? - PtosisQ - Miosise - A n hidrosisQ The degree of anisocoria is more marked in the dark than in light. - There is associated dilation lag, an asymeetry in papillary redilation between the two eyes when the light source is moved away .from the eye. - The homer's pupil will redilate more slowly (by 15 to 20 seconds) than the normal pupil. The ptosis is minor (less than 2 mm) and occurs as a result of paralysis of the Muller's muscle, which is innervated by the sympathetic pathway. The lower as well as the upper lid is affected producing the so-called "upside-down ptosis". Anhidrosis is present in central or preganglionic (first or second order) lesions. The sympathetic fibers responsible for facial sweating and vasolidation branch off at the superior cervical ganglion from the remainder of the oculosympathetic pathway; thus, anhidrosis is not a feature of postagangkonic or third-order lesions. This sign is .frequently not apparent to patients or clinicians. A congenital Horner's syndrome should be suspected when anisocoria is associated with heterochromia (unequal iris color, with the affected iris being lighter). - This occurs because formation of iris pigment in the first several months of age is under sympathetic control. This may only be apparent if the natural color is relatively dark. ETIOLOGY The etiology of Horner's syndrome in adults relates to the lesion location. First-order syndrome (central) Lesions of the sympathetic tracts in the brainstem or cervicothoracic spinal cord can produce a first-order Homer's syndrome. Lateral medullary syndromes (M.C.) - Brainstem disease (stroke, tumour, demyelinating disorder) - Syringomyelia - Cervical cord trauma (including surgery) - Spinal cord tumour - Diabetic autonomic neuropathy - Multiple sclerosis Second-order syndrome (preganglionic) - Trauma or surgery involving spinal cord, thoracic outlet lung apex. - Pancoast tumour - Carotid and Aoic aneurysm and dissection - Lumbar epidural anaesthesia. Third-order syndrome (Postganglionic) - Lesions of internal carotid aery such as - Dissection, thrombosis - Otitis media - Cavernous sinus mass Surgery for raynaud's syndrome (cervical sympathectomy) may cause trauma to cervical spinal cord.
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