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Do Cluster Headaches Cause Horner’s Syndrome & How Does Pancoast Tumor Cause It?

Do Cluster Headaches Cause Horner’s Syndrome?

Horner syndrome has a variety of causes which can cause it within a short period of time. Cluster headache is also one of the reasons for horner’s syndrome. In fact, the most common benign reason for horner’s syndrome is vascular headache also known as cluster headache. According to a study conducted, about 10 % of cases suffering from cluster headache are known to be suffering from horner’s s syndrome whether sooner or later in life.(1) The exact etiology of cluster headache also known as Horton syndrome is not known and also it is difficult to decipher how it causes the horner’s syndrome.(2) These are characterized by bouts of painful headaches ranging from 15 – 120 minutes each and are multiple in number. These can occur for a period of one week to one month or more and then a period of normal phase follows which can range from months to years. Although the mechanism is not quite clearly understood there is an increased flow of blood from the temporal arteries mostly seen as a unilateral phenomenon. It is associated with redness of eyes, lacrimation, miosis, dropping of eyelids, severe eye pain, loss of sweating on face, etc.(3) These are all known symptoms of horner syndrome.

Do Cluster Headaches Cause Horner's Syndrome?

Vascular headaches are the cause of usually third-order horner syndrome because the fibers affected in it are located intracranially in the cavernous sinus which is postganglionic in anatomical origin. The cluster headache can be terminated by the full flow of oxygen at 100 %. Medical treatment can be given to cut short the attack of cluster headache. Commonly used drugs are non-steroidal anti-inflammatory drugs but the most effective and the newest in business are triptan group of drugs like sumatriptan, naratriptan, etc.

How Does Pancoast Tumor Cause Horner’s Syndrome?

Mechanism of pancoast tumor causing Horner syndrome:

Pancoast tumor is a malignant tumor located at the apex of the lung and is one of the most common malignant causes responsible for Horner syndrome after the intracranially located malignancies. For knowing the cause of Pancoast tumors causing horner syndrome, it is necessary to understand the anatomy of the sympathetic fibers. First-order neurons of the sympathetic system arise intracranially from the hypothalamus and drop down to the spinal cord without crossing. From the spinal cord, there is a rise of preganglionic sympathetic fibers which exits from the spinal cord and ascends in a parallel fashion along with the vertebral column and passes near the subclavian artery and apex of the lung.

Since a Pancoast tumor is the lung tumor that is rare as compared to other lung cancers arises from the apex of the lung, it can impinge the sympathetic nerve fibers going near the apex and thus can involve them in the pathology.(4) It, therefore, causes the second-order of horner syndrome and the symptoms of miosis, ptosis can appear very early. For its treatment surgical approach as well as chemo or radiotherapeutic approach can be used depending upon the extent and the needs of the patient, but it should be treated as early as possible because once it damages the fibers permanently it will not be reversible.


Although there are a variety of causes associated with horner syndrome but few of the commonest benign causes are vascular headaches like a cluster headache. Apical lung tumor-like Pancoast tumor is among the malignant reasons for horner syndrome and usually counted after the intracranial malignancies. Cluster headache or other benign vascular headaches are usually the cause of third order of horner syndrome which involves postganglionic fibers due to its mechanism originating intracranially. Apical involvement like in Pancoast tumor and subclavian artery defects are the cause of second-order of horner syndrome which includes preganglionic fibers.


Also Read:

Sheetal DeCaria, M.D.
Sheetal DeCaria, M.D.
Written, Edited or Reviewed By: Sheetal DeCaria, M.D. This article does not provide medical advice. See disclaimer
Last Modified On:January 16, 2024

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