"Unequal pupils" for lightning protection in emergency consultations is a clinical necessity

Neurology is one of the major emergency patients, and I believe you may have experienced a series of life-threatening calls from various departments
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Sudden lateral limb weakness, slurred speech, facial paralysis, and other physical signs seem to directly point to a stroke, and the diagnosis and treatment ideas in the brain are also clear
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On the contrary, some relatively rare and complex symptoms or signs are even more troublesome
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The pupil is an important part of the clinical examination, and its size change may indicate a potential life-threatening disease
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As the "unit involved" in pupil changes, the nervous system cannot escape blame, and neurology is often the object of "accountability" for this reason
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So the question is, is pupil change really an emergency? Are there any "false" pupil changes? How should it be recognized in an emergency consultation? Author: Tsai This article is published by Yimaitong authorized by the author, please do not reprint without authorization
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How does the pupil change? The size of the pupil depends on the balance of the action of the two groups of iris muscles (the pupil dilator and the pupillary sphincter), and is related to the reflex adjustment produced by the intensity of the ambient light
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In addition, age, emotional state (adrenergic tone), wakefulness, and intraocular pressure may all affect pupil size
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Figure 1 Pupil-to-light reflection pathway (1) Pupil contraction is mediated by parasympathetic (cholinergic) nerve fibers running along the third pair of cranial nerves, which can be caused by light signals or myopic stimulation
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Optical signal → retinal ganglion cells → optic nerve → optic chiasm (the intersection of nasal fibers) → optic tract → dorsal midbrain pretectal nucleus (receiving bilateral ocular afferent signals) → bilateral EW nuclei → parasympathetic nerve fibers → Along the third pair of cranial nerves, enter the ciliary ganglion in the ipsilateral orbit → pupillary sphincter and ciliary muscle → adjust the lens
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The proximal reflex pathway descends from the higher cerebral cortex center directly into the EW nucleus, bypassing the pretectal nucleus on the dorsal side of the midbrain
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(2) Pupil dilation is mediated by the sympathetic (adrenergic) pathway of tertiary neurons originating from the hypothalamus
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Neuron → Hypothalamus → Cervical spinal cord (C8-T2 segment, also known as Budge ciliary spinal center) → Sympathetic trunk → Brachial plexus (running on the upper edge of the lung apex) → Superior cervical ganglion (located in the mandibular angle and common carotid artery) Near the bifurcation) → continue ascending in the capsule of the internal carotid artery, passing through the cavernous sinus → confluence with the V cranial nerve (trigeminal nerve) ophthalmic branch (V1) → innervate the pupil dilator muscle and Müller muscle (responsible for a small part of the upper eyelid) Elevation and lower eyelid retraction exercises)
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 How to evaluate the pupil? After so many years of walking around the rivers and lakes, everyone must be very skilled in checking pupils, but in fact, there are some small details that may be overlooked
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In order to ensure that I do not fall into the pit, the correct pupil inspection method can be described as a basic project
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1.
Inspection environment: Strictly speaking, pupil inspection is best performed in dim light, and it is better to turn off the light (of course, emergency consultation conditions may not allow it)
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2.
Testing tools: In fact, only a bright light beam is needed to evaluate the pupil.
The pupil pen is definitely good as a tailor-made one, and an ophthalmoscope with a light beam is not a bad idea
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In addition, the pupil size needs to be measured.
Some pupil pens have their own scales and special measuring rulers
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3.
Detection method: During the examination, the patient should relax and look at distant objects, avoid directly facing the light (may be caused by near pupil reflections to reduce pupils)
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At the same time, two-sided detection is required
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4.
Observation indicators: record the size, shape and position of each pupil in bright and dark environments
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The size, shape and position of the pupils on both sides of the normal person are symmetrical (the difference is less than 0.
4mm)
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5.
Reflection: a) Reflection on light: when the light enters the eye (observe the pupil contraction of both eyes) and then when the light moves down and leaves the eye, observe the pupil's reaction
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The amplitude, speed and symmetry of direct and indirect light reflection should be recorded
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b) Near reflection: Check the near reflection when the light reflection is abnormal
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It can be assessed with adjustable visual targets such as reading the near vision measurement card
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For patients who are unable to gather their eyes or are blind, ask the patient to put their thumb at the reading distance and ask the patient to look at their thumb, which can elicit near reflexes
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Under normal circumstances, the degree of pupil contraction caused by a close vision target is lower than that caused by direct light stimulation
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Large pupils and small pupils carefully evaluate pupil response in dark and bright environments to determine whether the abnormal pupil is a large pupil or a small pupil
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When there are abnormal large pupils and small pupils, different diseases need to be considered (Table 1)
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Table 1 Differential diagnosis of pupils with unequal large pupils The "true" pupil abnormalities you need to pay attention to.
The above mentioned a variety of possible factors for pupil size abnormalities, and some diseases need to be identified and dealt with in time
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Specific medical history and physical examination can help find the cause (Figure 2)
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It is worth noting that during the consultation process, clinicians need to pay extra attention to some details to help us discover relevant acute and critical illnesses in time
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In addition to obvious eye injuries, Horner syndrome and oculomotor nerve palsy may indicate certain cerebrovascular diseases, so urgent treatment is required
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➤Horner syndrome Horner syndrome can be caused by damage to any part of the sympathetic nerve (adrenergic) tertiary neuron pathway from the hypothalamus.
The typical clinical manifestations are pupil reduction, ptosis, and anhidrosis
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The degree of pupil size unequal in a dark environment is more pronounced than in a bright environment, with 15-20 seconds delayed pupil dilation
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Depending on the location of the injury, different causes can be traced (Table 2), among which black and bold diseases need to be paid attention to
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Table 2 Differentiation of the etiology of Horner syndrome in adults Horner's diagnostic test can be done by locally administering 1-2 drops of 4%-10% cocaine or aclonidine eye drops to identify physiological pupil sizes
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The enlargement of the normal pupil is greater than that of the Horner pupil, thus exacerbating the pupil size disparity, which does not exist in the physiological pupil size disparity
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 ➤Ocular nerve palsy along the path of the oculomotor nerve (from the midbrain oculomotor nucleus to the orbital and extraocular muscles) may cause oculomotor nerve palsy, including complete peripheral palsy (ptosis) , Eyeball adduction, upward and downward movement paralysis), complete central (pupillary sphincter dysfunction, dilated pupils and loss of reflex), partial central dysfunction (variable pupil size, slow reflection of light, but reflection Reserved)
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According to the injury, it can be divided into isolated or non-isolated lesions (Table 3)
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Among them, the most terrible cause of isolated acute oculomotor palsy is intracranial aneurysm, because it is accompanied by the risk of potentially fatal subarachnoid hemorrhage, head CT scan should be performed, and other tests should be continued if necessary to rule out the diagnosis
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 Table 3 Differentiation of the etiology of oculomotor nerve palsy Note: ICA: internal carotid artery; Pcom A: posterior communicating artery; PCA: posterior cerebral artery
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 Lightning protection "false" pupil unequal size After understanding the "true" pupil unequal size situation that really needs to be dealt with urgently, in this paragraph we will talk about the "pits" that are easy to step on in the clinical diagnosis and treatment process
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In other words, the patient has a situation where pupils are not equal, but may have nothing to do with the disease itself, or a "false" emergency consultation that does not require emergency treatment
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➤Physiological unequal size At any given time, about 20% of the normal population can see physiologic or simple pupil sizes
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This is often overlooked when patients are admitted to the hospital for acute onset
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The identification method mainly includes the following two points: look at old photos + light inspection! Check the patient’s ID card or driver’s license (or other available old photos) to see if the patient’s previous pupils are congenital
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Through light inspection, it can be found that the degree of unequal degree is basically the same in bright and dark environments, or slightly worse in dark environment; the degree of unequal pupil size on both sides is generally less than 0.
4mm, no pupil dilation delay, and pupil size is different The situation may change with the brightness of the ambient light, and there may be alternate changes in the eyes
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 ➤Structural defects Iris structural defects can lead to unequal pupil sizes and abnormal pupil shapes.
The etiology can be divided into congenital and acquired
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In the course of clinical practice, the patient’s previous eye diseases and surgical history are critical to finding the cause of the acquired disease.
At the same time, it is necessary to pay attention to finding whether it is combined with the primary disease
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Congenital defects, such as aniridia, iris defect, congenital ectopic pupils, residual pupil membranes, multiple pupils, congenital heterochromia of the iris, Rieger syndrome and other abnormalities of the anterior segment of the eye, can lead to unequal pupil sizes, usually Appears in childhood
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Acquired: Intraocular inflammation (iritis/iridocyclitis), anterior segment ischemia, trauma, surgical injury or traumatic injury related iris sphincter atrophy, mechanical deformation caused by intraocular tumors, and angle-closure glaucoma
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Such diseases are often accompanied by the manifestations of the primary disease, or they can be identified through examinations such as slit lamps
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 ➤Drug-related clinical diagnosis and treatment often use a variety of drugs.
Eye drugs are generally not easily overlooked, while other systemic drugs that may cause pupil changes are often ignored (Table 4)
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The pupil changes caused by the drug are mainly caused by mydriasis (the drug stimulates the sympathetic nerve innervating the pupil dilator muscle or inhibits the parasympathetic nerve innervating the pupillary sphincter)
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The pupil dilation caused by anticholinergic drugs is usually large (≥8mm) and does not shrink when exposed to light; sympathomimetic drugs rarely dilate the pupil by 1mm or more
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Pharmacological dilated pupils are not accompanied by pain, ptosis and diplopia
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Table 4 Summary of drugs that cause mydriasis ➤ Special signs-ankylosing pupil (Adie pupil) is related to abnormal reinnervation of the ciliary ganglion or short ciliary nerve after damage
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The acute phase may only manifest as unilateral mydriasis with poor response to light, and other manifestations within a few days or weeks: such as light-near reflex separation (the pupil contracts poorly to light, but the accommodative reflex is better); tonic response ( When entering a dark environment from a bright environment or after looking at a near object, the initially larger pupil of Adie becomes smaller than the normal pupil on the opposite side, and continues to contract rigidly, and then expand very slowly); denervation sensitization (2 drops in each eye) A drop of 0.
1% pilocarpine, the initially larger pupil of Adie becomes smaller than the normal pupil on the opposite side within 30 minutes, and the size of the normal pupil is usually unchanged)
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When Adie pupils appear, a variety of diseases need to be considered, including infectious, inflammatory, etc.
(Table 5), combined with other symptoms and signs for comprehensive evaluation
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Most patients do not need any treatment, and patients with underlying systemic causes should deal with the primary disease
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The prognosis is generally good, and most patients only need comfort treatment
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 Table 5 Summary of the etiology of Adie’s pupils.
The eyes are the windows of the soul.
The pupils are the key to the light transmission of the windows, and they are also an important tool to reflect the function of the windows
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In actual situations, there are many factors affecting pupil size.
Careful and correct physical examination and timely diagnosis and screening are critical for the diagnosis and treatment of critical illnesses such as aneurysms and strokes (Figure 2)
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In addition, identifying "false" pupils with unequal largeness can avoid excessive medical treatment and provide a "stabilizer" for the consultation life! Figure 2 Recognition of unequal pupils Note: *The smaller pupil dilates more slowly than the healthy pupil in the first 5s under dark light, that is, the Horner pupil
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Autonomic control of the eye.
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Approach to the patient with anisocoria.
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An approach to anisocoria.
Current opinion in ophthalmology, 2016, 27(6): 486-492.
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Anisocoria.
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Apraclonidine for the pharmacologic confirmation of acute Horner syndrome.
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