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Horner syndrome
Congenital neurological disorders: Pathology review
Headaches: Pathology review
Seizures: Pathology review
Cerebral vascular disease: Pathology review
Traumatic brain injury: Pathology review
Spinal cord disorders: Pathology review
Dementia: Pathology review
Central nervous system infections: Pathology review
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Neuromuscular junction disorders: Pathology review
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Horner syndrome
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Horner syndrome p. 559, 719
Horner syndrome p. 549
labs/findings p. 723
lung cancer p. 709
Pancoast tumor p. 710
presentation p. 719
Horner syndrome p. 549, 719
Horner syndrome and p. 559
Horner syndrome p. 560, 719
Horner syndrome p. 559
Filip Vasiljević, MD
Brittany Norton, MFA
Evan Debevec-McKenney
Tanner Marshall, MS
Horner’s syndrome, named after the ophthalmologist Johann Friedrich Horner, is caused by a problem with the sympathetic nerve supply to one side of the face.
This disruption results in miosis, which is constricted pupil; ptosis, a droopy eyelid; and anhidrosis, a failure to sweat.
Broadly speaking, the autonomic nervous system is a part of the nervous system that controls involuntary body functions like the heart rate, blood pressure and digestion.
The autonomic nervous system can be subdivided into the sympathetic and parasympathetic nervous system, which have opposite effects.
The sympathetic nervous system controls functions like increasing heart rate, blood pressure, and slowing digestion. All of this maximizes blood flow to the muscles, and can help you either run away from a threat or fight it which is why it’s also called the fight-or-flight response.
The parasympathetic nervous system has the opposite effect; it slows heart rate, decreases blood pressure, and stimulates digestion - the effects can be summarized as 'rest and digest'.
Now, with regard to the face and eye, there’s an oculosympathetic pathway with three groups of neurons called first-order, second-order and third-order neurons.
The body of the first-order neuron is located in the hypothalamus, and it’s axon extends down into the spinal cord, where it synapses with the second-order neuron.
The body of the second-order neuron is located in the cervical region of the spinal cord, and it’s axon exits the spinal cord and enters the sympathetic chain, which is a structure full of sympathetic ganglions or nerve cell bodies, and it runs along both sides of the spine.
Horner syndrome is a neurological disorder characterized by the combination of three main symptoms: ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (lack of sweating on one side of the body).
Most cases of horner syndrome are caused by damage to the sympathetic nervous system, which can be due to a stroke, tumor, or injury. Less common causes include infections, autoimmune disorders, and medications. Some people also develop horner syndrome as a side effect of cancer treatment.
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