Disturbance of pupillary reactions

The normal pupil always responds to light (direct and friendly reactions) and to convergence.

[1], [2], [3], [4], [5], [6], [7]

The causes of violations of pupillary reactions are:

1. Lesions of the optic nerve. The blind eye does not respond to direct light in its isolated light and there is no friendly reduction of the sphincter of the other eye, but the blind eye responds with a friendly reaction if its third nerve is intact and if the other eye and its optic nerve are not damaged.
2. Lesions of the oculomotor nerve. With damage to the III nerve, a direct and friendly reaction to light is absent on the affected side due to paralysis of the pupil sphincter, but a direct and friendly reaction remains preserved on the opposite side.
3. Other reasons are:
   • Eddie Syndrome.
   • It should be noted a special type of pupillary disorders, when there is paralysis of pupillary reflexes with no reaction to light, but a preserved response to convergence. This pathology is described under various conditions: neurosyphilis, Eddy syndrome, diabetes mellitus, pinealoma, pathological regeneration after oculomotor nerve injury, encephalitis, multiple sclerosis, ophthalmic herpes, eye trauma, dystrophic myotonia, pandisavtonomia (familial autonomic dysfunction Riley-Deia syndrome), syndrome Fisher, type I NMSN (Charcot-Marie-Tooth disease).

Some pupillary phenomena in patients in coma

The shape, size, symmetry and response of the pupils to light reflect the state of the oral sections of the brainstem and the functions of the third nerve in patients in coma. The reaction of pupils to light is very sensitive to structural damage in this area of the brain, but at the same time is very resistant to metabolic disorders. Violation of this reflex, especially when it is unilateral, is the most important sign that allows us to distinguish metabolic coma from comatose conditions caused by structural damage to the brain.

1. Small, well-responsive pupils of the patient in the unconscious state ("diencephalic pupils") speak, as a rule, of the metabolic nature of coma.
2. The appearance of myosis and anhidrosis by the hemitis (Horner's syndrome), ipsilateral to brain damage, reflects the involvement of the hypothalamus on this side and is often the first sign of the initiating transcendental wedging in the supratentorial volumetric processes that cause the coma.
3. The average pupil size (5-6 mm) with spontaneous alpha-cillations of their size (hippus) becomes wider with pinching in the neck (ciliospinal reflex). This phenomenon reflects damage to the midbrain or prefectural areas.
4. A pronounced bilateral miosis ("point" pupils) with the inability to cause their reaction to light is characteristic of the primary lesion of the cover of the variolium bridge (and the cerebellum).
5. Horner's syndrome, ipsilateral to brain damage, may reflect a pathological process in the lateral sections of the variolium bridge, the lateral part of the medulla oblongata, and the ventrolateral sections of the cervical spinal cord on the same side.
6. Sluggish reaction of the pupil to light or its absence with a widely dilated pupil (7-8 mm) is due to the preservation of sympathetic pathways (the pupil of Hutchison). In this case, the oval shape of the pupil is caused by the uneven paresis of the pupil sphincter, which leads to the eccentric antagonistic effect of the pupil dilator. This phenomenon speaks of the peripheral lesion of parasympathetic fibers reaching the sphincter of the pupil in the composition of the third nerve.
7. Fixed, non-responsive pupils of medium width can be observed with direct damage to the midbrain (tumors, hemorrhages, infarcts). The defeat of the oculomotor nerves between their nuclei causes ophthalmoplegia. This paralysis of the III nerves is often bilateral, in contrast to their peripheral paralysis, which usually occurs on the one hand. 

Disturbance of pupillary reactions

1. Simultaneous disturbance of pupillary reaction to light, convergence and accommodation is clinically manifested by mydriasis. With one-sided defeat, the reaction to light (direct and friendly) on the affected side is not caused. This immobility of the pupils is called internal ophthalmoplegia. This reaction is caused by the parasympathetic pupillary innervation from the Yakubovich-Edinger-Westphal nucleus to its peripheral fibers in the eyeball. This type of impaired pupillary reaction can be observed with meningitis, multiple sclerosis, alcoholism, neurosyphilis, cerebrovascular diseases, head trauma.
2. Violation of a friendly reaction to light is manifested by anisocoria, mydriasis on the affected side. In the intact eye, a direct reaction is maintained and is weakened by a friendly response. In a sick eye, there is no direct reaction, but a friendly reaction is preserved. The reason for this dissociation between the direct and friendly response of the pupil is the damage to the retina or optic nerve before the crossing of the visual fibers.
3. Amavrotic motionlessness of the pupils to light is detected with bilateral blindness. At the same time, both direct and friendly reaction of pupils to light is absent, and convergence and accommodation remain. Amavrotic pupillary areflexia is caused by bilateral defeat of visual pathways from the retina to the primary visual centers inclusive. In cases of cortical blindness or in the defeat of both sides of the central visual pathway from the outer crankshaft and from the cushion of the optic thalamus to the occipital visual center, the response to light, direct and friendly, is completely preserved, since the afferent visual fibers terminate in the anterior dichotomy. Thus, this phenomenon (amaurotic pupil immobility) indicates a two-way localization of the process in the visual pathways up to the primary visual centers, whereas bilateral blindness with preservation of direct and friendly reaction of the pupils always indicates the defeat of the visual pathways above these centers.
4. The grammatical reaction of the pupils consists in the fact that both pupils are contracted only when the functioning half of the retina is illuminated; when the same half of the retina is illuminated, the pupils do not contract. This reaction of the pupils, both direct and friendly, is caused by the defeat of the visual tract or subcortical visual centers with the front tubercles of the quadruple, as well as crossed and non-crossed fibers in the region of the chiasma. Clinically almost always combined with hemianopsia.
5. The asthenic reaction of the pupils is expressed in rapid fatigue and even in the complete cessation of constriction with repeated light exposures. There is such a reaction in infectious, somatic, neurological diseases and intoxications.
6. The paradoxical reaction of the pupils is that when the light is exposed, the pupils widen, and narrow in the dark. It occurs exceptionally rarely, mainly with hysteria, still cutting at the dorsal, the insults.
7. With increased reaction of pupils to light, the reaction to light is more lively than normal. Occurs sometimes with light concussions of the brain, psychosis, allergic diseases (Quincke's edema, bronchial asthma, urticaria).
8. The tonic reaction of the pupils consists in an extremely slow dilatation of the pupils after their narrowing with light exposure. This reaction is caused by increased excitability of parasympathetic pupillary efferent fibers and is observed mainly in alcoholism.
9. Myotonic reaction of pupils (papillotonia), pupillary disorders of the type of Epidi can occur in diabetes mellitus, alcoholism, avitaminosis, Guillain-Barre syndrome, peripheral vegetative disorder, rheumatoid arthritis.
10. Pupillary disorders of the Argyle Robertson type. The clinical picture of Argyl Robertson syndrome, which is specific for syphilitic damage to the nervous system, includes such signs as miosis, small anisocoria, lack of response to light, pupillary deformation, bilateral disturbances, constant pupil sizes throughout the day, no effect from atropine, pilocarpine and cocaine . A similar picture of pupillary disorders can be observed in a number of diseases: diabetes, multiple sclerosis, alcoholism, cerebral hemorrhage, meningitis, Huntington's chorea, pineal gland adenoma, pathological regeneration after paralysis of oculomotor muscles, myotonic dystrophy, amyloidosis, Parino syndrome, Munchmeyer syndrome lies at the basis of interstitial edema of the muscles and subsequent proliferation of connective tissue and calcification), sensory neuropathy of Denny-Brown (congenital absence of bolevo sensitivity of the pupils to the light, sweating, increased blood pressure and increased heart rate with severe pain stimuli), pandisavtonomia, family disautonomy Riley - Dey, Fisher syndrome (acute development of complete ophthalmoplegia and ataxia with decreased proprioceptive reflexes), Charcot-Marie's disease - That's it. In these situations, Argyle Robertson's syndrome is called nonspecific.
11. Premortal pupillary reactions. A great diagnostic and prognostic value is the study of pupils in comatose states. With deep loss of consciousness, with severe shock, coma, the pupils' reaction is absent or sharply reduced. Immediately before death, the pupils in most cases strongly narrowed. If, in a comatose state, miosis is gradually replaced by progressive mydriasis, and the pupillary reaction to light is absent, then these changes indicate the proximity of death.

Below are the pupillary disorders associated with impaired parasympathetic function.

1. The response to light and pupil sizes under normal conditions depends on adequate light reception with at least one eye. In a completely blind eye there is no direct reaction to light, but the pupil dimensions remain the same as those on the side of the intact eye. In the case of complete blindness to both eyes, when lesioned in the anterior zone from the lateral geniculate bodies, the pupils remain enlarged, not reacting to light. If, however, bilateral blindness is caused by destruction of the cortex of the occipital lobe, then the light pupillary reflex is preserved. Thus, it is possible to meet completely blinded patients with normal pupillary reaction to light.

Defeats of the retina, optic nerve, chiasma, optic tract, retrobulbar neuritis with multiple sclerosis cause some or other changes in the functions of the afferent system of the pupil reflex, which leads to a disruption of the pupillary reaction known as the pupil of Marcus Gunn. Normally, the pupil reacts to bright light with a rapid constriction. Here the reaction is slower, incomplete and so short that the pupil can immediately begin to expand. The reason for the pathological reaction of the pupil is to reduce the number of fibers that provide a light reflex on the side of the lesion.

2. The defeat of one visual tract does not lead to a change in the size of the pupil due to the preserved light reflex on the opposite side. In this situation, the illumination of intact parts of the retina will give a more pronounced pupil response to light. This is called the pupillary reaction of Wernicke. To cause such a reaction is very difficult because of the dispersion of light in the eye.
3. Pathological processes in the middle brain (the zone of anterior tubercles of the quadruple) can affect the fibers of the reflex arc of the pupil's reaction to light that cross in the brain's aqueduct. The pupils are enlarged and do not respond to light. Often this is combined with the absence or restriction of the movements of the eyeballs upward (vertical paresis of the eye) and is called the Parino syndrome.
4. Argyle Robertson Syndrome.
5. With the complete defeat of the third pair of cranial nerves, the pupils are dilated due to the absence of parasympathetic influences and the continuing sympathetic activity. In this case, signs of damage to the motor system of the eye, ptosis, deviation of the eyeball in the lower-lateral direction are detected. Causes of severe lesion of the pair can be aneurysm of the carotid artery, tentorial hernia, progressive processes, the Tolosa-Hunt syndrome. In 5% of cases with diabetes mellitus there is an isolated lesion of III cranial nerve, the pupil thus often remains untouched.
6. The syndrome of Epidi (puillotlotonia) - degeneration of the nerve cells of the ciliary ganglion. There is a loss or weakening of the pupil's reaction to light with a conserved response to the setting of the gaze near. One-sidedness of the lesion, dilatation of the pupil, its deformation are characteristic. The phenomenon of papillotonia consists in the fact that the pupil converges very slowly during the convergence and returns very slowly (sometimes only for 2-3 min) to the original size after the convergence ceases. The size of the pupil is variable and varies throughout the day. In addition, the pupil enlargement can be achieved by prolonged stay of the patient in the dark. There is an increase in pupil sensitivity to vegetative substances (a sharp expansion from atropine, a sharp narrowing from pilocarpine).

This hypersensitivity of the sphincter to cholinergic drugs is detected in 60-80% of cases. In 90% of patients with tonic pupils of Eidi weakened or absent tendon reflexes. Such a weakening of the reflexes is common, capturing the upper and lower limbs. In 50% of cases a bilateral symmetrical lesion is observed. Why tendon reflexes are weakened in the syndrome of Adi is unclear. Hypotheses are offered about widespread polyneuropathy without sensory disturbances, degeneration of spinal ganglion fibers, peculiar form of myopathy, defect of neurotransmission at the level of spinal synapses. The average age of the disease is 32 years. More common in women. The most common complaint, in addition to anisocoria, is the blurring of the vision near when examining nearby objects. Approximately 65% of cases on the affected eye there is a residual paresis of accommodation. After a few months there is a pronounced tendency to normalize the power of accommodation. At 35% of patients at each attempt to look close on the amazed eye it is possible to provoke an astigmatism. Presumably this is due to segmental paralysis of the ciliary muscle. When examining in the light of a slit lamp, one can note a difference in the pupil sphincter in 90% of the affected eyes. This residual reaction is always a segmental reduction in the ciliary muscle.

Over the years, the pupil constriction appears on the affected eye. There is a pronounced tendency to the appearance, after several years, of a similar process on the other eye, so that anisocoria becomes less noticeable. In the end, both pupils become small and react poorly to light.

Recently, it was found that the dissociation of the pupil's response to light and accommodation, often observed in the syndrome of Adi, can be explained only by diffusion of acetylcholine from the ciliary muscle into the posterior chamber towards the denervated sphincter of the pupil. It is likely that the diffusion of acetylcholine into watery moisture contributes to the intensity of the iris movements in the syndrome of Adi, but it is also quite clear that this dissociation can not be explained so unambiguously.

The pronounced response of the pupil to accommodation is most likely due to the pathological regeneration of accommodative fibers in the pupil sphincter. The nerve of the iris has an amazing ability to regenerate and re-innervate: the heart of the rat fruit, transplanted into the anterior chamber of the adult's eye, will grow and contract in a normal rhythm that may vary depending on the rhythmic stimulation of the retina. The iris nerves can grow into the transplanted heart and set the heart rate.

In most cases, the syndrome of Adi is an idiopathic disease, and the cause of its occurrence can not be found. Secondary Aidi syndrome can occur in various diseases (see above). Family cases are extremely rare. The cases of combination of the syndrome of Adi with vegetative disorders, orthostatic hypotension, with segmental hypohyroz and hyperhidrosis, diarrhea, constipation, impotence, local vascular disorders are described. Thus, the Eidi syndrome can act as a symptom at a certain stage of development of a peripheral vegetative disorder, and sometimes it can be its first manifestation.

The dull trauma of the iris can lead to the rupture of short ciliated branches in the sclera, which is clinically manifested by the deformation of the pupils, their expansion and violation (weakening) of the reaction to light. This is called post-traumatic iridoplegia.

Ciliated nerves can be affected by diphtheria, resulting in dilated pupils. Usually it occurs on the 2-3rd week of the disease and is often combined with the paresis of the soft palate. Dysfunction pupils, as a rule, completely restored.

Pupillary disorders associated with impaired sympathetic function

The defeat of sympathetic pathways at any level is manifested by Horner's syndrome. Depending on the level of damage, the clinical picture of the syndrome may be complete and incomplete. Full Horner's syndrome is as follows:

1. narrowing of the glottis. Cause: paralysis or paresis of the upper and lower tharsal muscles receiving sympathetic innervation;
2. miosis with a normal reaction of the pupil to light. Cause: paralysis or paresis of the muscle that dilates the pupil (dilator); the intactness of the parasympathetic pathways to the muscle that narrows the pupil;
3. enophthalmos. Cause: paralysis or paresis of the orbital muscle of the eye receiving sympathetic innervation;
4. homolateral anhidrosis of the face. Reason: violation of sympathetic innervation of the sweat glands of the face;
5. hyperemia of the conjunctiva, vasodilation of the vessels of the skin of the corresponding half of the face. Reason: paralysis of the smooth muscles of the vessels of the eye and face, loss or deficiency of sympathetic vasoconstrictor influences;
6. heterochromia of the iris. Reason: sympathetic failure, as a result of which migration of melanophores into iris and vascular membranes is disturbed, which leads to disruption of normal pigmentation at an early age (up to 2 years) or depigmentation in adults.

Symptoms of incomplete Horner's syndrome depend on the level of damage and degree of involvement of sympathetic structures.

Horner's syndrome can have a central origin (defeat of the first neuron) or peripheral (defeat of the second and third neurons). Large studies among hospitalized in neurological departments of patients with this syndrome revealed its central origin in 63% of cases. His relationship to stroke was established. In contrast, researchers who observed outpatients in eye clinics found the central nature of Horner's syndrome in only 3% of cases. In domestic neurology, it is commonly believed that Horner's syndrome with the greatest regularity occurs in the peripheral defeat of sympathetic fibers.

Congenital Horner's syndrome. The most common cause of it is birth trauma. The immediate cause is damage to the cervical sympathetic chain, which can be combined with a lesion of the brachial plexus (most often its lower roots - paralysis Dejerine-Clumpke). Congenital Gorner syndrome is sometimes combined with facial hemiatrophy, with abnormalities of the intestine, cervical spine. To suspect congenital Horner's syndrome is possible by ptosis or heterochromia of the iris. It also occurs in patients with cervical and mediastinal neuroblastoma. All newborns with Horner's syndrome are offered to diagnose this disease by radiographing the chest and screening method to determine the level of excretion of mandelic acid, which in this case is elevated.

For congenital Gorner syndrome the most characteristic is the iris heterochromia. Melanophores migrate to the iris and vascular membranes during embryonic development under the influence of the sympathetic nervous system, which is one of the factors affecting the formation of the melanin pigment, and thus determines the color of the iris. In the absence of sympathetic influences, pigmentation of the iris may remain insufficient, its color will become light-blue. Eye color is established a few months after birth, and the final pigmentation of the iris ends at the age of two. Therefore, the phenomenon of heterochromia is observed mainly in congenital Horner's syndrome. Depigmentation after violation of sympathetic innervation of the eye in adults is extremely rare, although some well-documented cases are described. These cases of depigmentation testify to the continuing sympathetic effects on melanocytes in adults.

Horner's syndrome of central origin. Hemispherectomy or an extensive heart attack of one hemisphere can cause Horner's syndrome on her side. Sympathetic ways in the brain stem along its entire length go in the vicinity of the spinotalamic tract. As a result, Horner's syndrome of stem origin will be observed simultaneously with a violation of pain and temperature sensitivity on the opposite side. The causes of such damage can be multiple sclerosis, glioma of the bridge, trunk encephalitis, hemorrhagic stroke, thrombosis of the posterior inferior cerebellar artery. In the last two cases, in the onset of vascular disorders, Horner's syndrome is observed together with severe dizziness, vomiting.

When involved in the pathological process, in addition to the sympathetic pathway, the V or IX nuclei, the X pairs of cranial nerves, there will be correspondingly analgesia, face thermal term on the ipsilateral side or dysphagia with soft palate, pharyngeal, vocal cords.

Due to the more central location of the sympathetic pathway in the lateral columns of the spinal cord, the most common causes of damage are cervical syringomyelia, intramedullary spinal tumors (glioma, ependymoma). Clinically, this is manifested by a decrease in pain sensitivity on the hands, a decrease or loss of tendon and periosteal reflexes from the hands and bilateral Horner syndrome. In such cases, the ptosis from the two sides first of all attracts attention. Pupils narrow symmetrical with normal reaction to light.

Horner's syndrome of peripheral origin. The defeat of the first thoracic root is the most common cause of Horner's syndrome. It should, however, immediately be noted that the pathology of the intervertebral discs (hernia, osteochondrosis) is rarely manifested by Horner's syndrome. Passage of the first thoracic root directly above the pleura of the apex of the lung determines its defeat in malignant diseases. The classic Pancost syndrome (lung cancer) is manifested by pain in the armpit, atrophy of the muscles (small) arms and Horner's syndrome on the same side. Other causes are neurofibroma root, extra cervical ribs, Dejerine-Klyumpke paralysis, spontaneous pneumothorax, other diseases of the apex of the lung and pleura.

A sympathetic chain at the cervical level can be damaged due to surgical interventions on the larynx, thyroid gland, neck injuries, tumors, especially metastases. Malignant diseases in the area of the jugular opening on the basis of the brain cause various combinations of Horner's syndrome with the defeat of IX, X, XI and HP of cranial nerve pairs.

If the lesion is higher than the upper cervical ganglion of fibers that go into the interweaving of the internal carotid artery, Horner's syndrome will be observed, but only without sweating, as the ship's pathways to the face are part of the plexus of the external carotid artery. Conversely, sweating disorders without pupillary disorders will occur with the involvement of the fibers of the outer carotid plexus. It should be noted that a similar picture (anhidrosis without pupillary disorders) can be observed in the defeat of the sympathetic chain caudal to the stellate node. This is because sympathetic paths to the pupil, passing through the sympathetic trunk, do not fall below the stellate node, while the sudomotor fibers that go to the sweat glands of the face leave the sympathetic trunk, starting from the superior cervical ganglion and ending with the upper thoracic sympathetic ganglia.

Injuries, inflammatory or blastomatous processes in the immediate vicinity of the trigeminal (gasser) node, as well as syphilitic osteitis, carotid aneurysm, trigeminal aneurysm, herpes ophthalmicus are the most common causes of Raeder's syndrome: defeat of the first branch of the trigeminal nerve in combination with Horner's syndrome. Sometimes, the defeat of the cranial nerves of the IV, VI pair is added.

The Purfur du Ptis syndrome is the inverse Horner syndrome. In this case, mydriasis, exophthalmos and lagophthalmos are observed. Additional symptoms: increased intraocular pressure, changes in the vessels of the conjunctiva and retina. This syndrome occurs with the local action of sympathomimetic agents, rarely with pathological processes in the neck, when sympathetic trunk is involved in them, as well as with hypothalamus stimulation.

[8], [9], [10],

Specific forms of pupillary disorders

This group of syndromes includes cyclic oculomotor paralysis, ophthalmoplegic migraine, benign episodic unilateral mydriasis and tadpole pupil (intermittent segmental spasm of the dilator lasting several minutes and repeating several times a day).

Pupils of Ardzhil-Robertson

The pupils of Ardzhil-Robertson are small, unequal in size and irregularly shaped pupils with a poor response to light in the dark and a good reaction to accommodation with convergence (dissociated pupil response). It is necessary to differentiate the Arjil-Robertson symptom (a relatively rare sign) and Edy's two-sided tonic pupils, which occur more often.