Biomedical subjects

M Heuck

Publications and source records attributed to M Heuck.

3 recordsLinked to original sources

PubMed1997

The enhanced ciliospinal reflex in asymptomatic patients with cluster headache is due to preganglionic sympathetic mechanisms.

An amplified ciliospinal reflex response has been documented in patients with cluster headache, lacking a Horner-like syndrome. The mechanism is unknown. Tentatively, it may be due to an increased release of monoamines from post-ganglionic sympathetic nerve endings or an increased density of postsynaptic adrenergic receptors in the dilatator muscle of the iris. The instillation of a 1% phenylephrine solution into the conjunctival sac induces mydriasis by stimulating postsynaptic adrenergic receptors in the dilatator muscle of the iris, while the instillation of a 2% tyramine solution causes mydriasis by releasing noradrenaline from the presynaptic sympathetic nerve terminals in the iris. According to these premises, a positive correlation should be expected between the ciliospinal reflex response and the pupillary response to tyramine, if the enhanced ciliospinal reflex response was due to an increased presynaptic release of monoamines. No such correlation was found. Nor was there any positive correlation between the ciliospinal reflex response and the pupillary response to phenylephrine, contradicting an increased density of postsynaptic monoaminergic receptors in the dilatator muscle of the iris as the explanation. However, there was a significant positive correlation between the pupillary responses to phenylephrine and tyramine, ruling out any functionally caused "denervation" hypersensitivity in the dilatator muscle of the iris. It is concluded that the amplified ciliospinal reflex response in cluster headache patients (lacking a Horner-like syndrome) reflects compensatory pathophysiological mechanisms proximal to the third-order sympathetic neuron.

Adult↗

PubMed1996

Ciliospinal reflex response in cluster headache.

The ciliospinal reflex response is mainly mediated by second- and third-order sympathetic nerves to the dilatator muscle of the iris. As the pupillary response to various pharmacological agents indicates a sympathetic dysfunction in patients with cluster headache, the ciliospinal reflex was studied in 25 patients. Five of these patients with cluster headache exhibited a Horner-like syndrome (miosis, ptosis) on the symptomatic side. The pupillary responses to phenylephrine and tyramine showed that the Horner-like syndrome was due to postganglionic sympathetic nerve dysfunction. Their ciliospinal reflex response on the symptomatic side was significantly less than in controls and in other patients with cluster headache, lacking a Horner-like syndrome. This also applied to the nonsymptomatic side compared to the majority of cluster headache patients without any clinical evidence of sympathetic nerve dysfunction. These findings seem to delineate those patients with a Horner-like syndrome as a subgroup, distinctly separated from the majority of cluster headache patients. Furthermore, the findings indicate that the Horner-like syndrome is not a consequence of repeated attacks of headache over many years, but is a manifestation of bilateral cephalic sympathetic dysfunction being more marked on the symptomatic side. In 18 (72%) of our 25 patients, an asymmetric and lower ciliospinal reflex response on the symptomatic side was seen. In 3 (12%) patients, there was no difference in the response. In 4 patients (16%), the incorrect side was indicated by an asymmetric reflex response. Two of these patients (8%) had suffered from cluster headache on alternating sides. In summary, the findings support the concept that dysfunction of the sympathetic nervous system, whether peripheral or central is involved in the pathophysiology of cluster headache.

Adult↗

PubMed1992

Measurement of progressive disc change in glaucoma.

We describe a videographic procedure for detecting minute changes in disc topography of glaucomatous eyes that involves measuring the displacement of selected circumlinear vessels. The problem of recognizing the difference between parallactic errors and true changes in topography is emphasized.

Female↗