Horner's Syndrome: A Medical Discovery from the American Civil
War
Unequally sized pupils in combination with a drooping eyelid on
the side of the smaller pupil and decreased sweating on the same
side of the face is known as Horner's syndrome, named for Johann
Friedrich Horner, a Swiss ophthalmologist who wrote up a case in
1869. When present, Horner's syndrome indicates interruption of
the sympathetic nervous system on that side of the body and is
still a valuable tool in modern diagnosis.
The sympathetic nervous system helps govern various functions
outside conscious control, like pulse, blood pressure, sweating,
etc. The portion of the sympathetic pathway influencing the eyes
and face follows a convoluted pathway that starts in the brain
and flows down through the brainstem to the spinal cord. At the
base of the neck, the pathway passes outward from the spinal
cord and through the top of the lung. From there it rises
through the neck again and into the head where it finally
reaches the eye and face. A pair of otherwise identical
sympathetic pathways serves each side of the head.
While Horner's observations were valid and the syndrome has been
known by his name ever since, he was not the first to recognize
this condition. Instead, an American physician by the name of
William Keen first diagnosed a case of "Horner's syndrome" in an
injured Union soldier during the American Civil War. The
soldier, Edward Mooney, had been shot through the right side of
his neck at the battle of Chancellorsville.
In 1864, along with fellow physicians, Silas Weir Mitchell and
George Morehouse, Keen published a small book, "Gunshot Wounds
and Other Injuries of the Nerves," that included Mooney's case
report under the title "Wound of the Sympathetic Nerve." Fresh
out of medical school when he entered military service, Keen
made the diagnosis upon recognizing the similarities between the
soldier's face and that of a cat illustrated in a textbook of
physiology.
In 1905, near the end of Keen's career as a pioneering
neurosurgeon, the College of Physicians of Philadelphia
published his reminiscences about the case:
"The first nervous case that I remember was a very remarkable
one, and the first of its kind ever recorded. It occurred while
I was executive officer at the Satterlee Hospital, West
Philadelphia. As executive officer it was my duty to assign new
patients to the wards, and also to transfer the cases in the
specialties, such as the eye, nervous diseases, and injuries,
etc., to the special hospitals. One morning, as I sat at my
desk, a soldier applied for assignment. On looking up at him I
said to myself: 'You are Dalton's cat.'
"Those familiar with Dalton's good old textbook of physiology
will remember a cat whose right cervical sympathetic nerve [the
portion in the neck] had been severed. The left pupil is very
large, the right one very small, and the moment I looked at this
man I was struck by the similar condition of his pupils. I
quickly asked him, 'Where are you wounded?' and when he pointed
to his neck I said to myself again, 'That ball destroyed the
sympathetic nerve.'
"In the autumn of 1864 I took a copy of [our] book to Claude
Bernard, in Paris, [a legendary physiologist and] the discoverer
of the function of the cervical sympathetic and the effect of
its division [cutting] upon the pupil and the blood vessels. He
exhibited true Gallic enthusiasm when I showed him the first
recorded case in the human subject, which confirmed his
brilliant researches."
"Dalton's cat" was a drawing in John Call Dalton's "A Treatise
on Human Physiology." Keen attended Jefferson Medical College in
Philadelphia between 1860 and 1862, and may have seen the
drawing in either the first edition (1859) or second edition
(1862). At a time when medicine was struggling to gain a
scientific footing, Dalton's writings were notable for being
based on experimental observations. Dalton was one of America's
first physiologists and had studied with Claude Bernard after
graduating from Harvard Medical School in 1847.
(C) 2006 by Gary Cordingley