EMCrit.org | Emergency Department Critical Care - Brain and Cranial Nerve Disorders

Although there are very few data in the literature regarding CN III palsy presenting as an isolated dilatated pupil with normal oculomotor function and without ptosis, it is generally agreed to be extremely rare; an aneurysmal cause is even rarer (6).

The more common causes of the isolated dilatated pupil include exposure to pharmacologic agents, trauma to the iris or ciliary ganglion, glaucoma, and Adie's tonic pupil. These can be determined using simple tests that can be performed in the ED. A number of authors have suggested a stepwise approach to determining the etiology of a dilatated pupil ([7] and [8]).

First, determine whether the pupil reacts normally. If it constricts briskly to direct light, then the problem may be a lack of sympathetic tone in the contralateral eye, making the “normal” ipsilateral eye appear dilatated. This can be caused by disruption of the sympathetic pupillary fibers (such as in Horner's syndrome) or by pharmacologic agents such as pilocarpine. Additionally, up to 20% of the population may have a slight physiologic anisocoria, usually 1 mm or less (9). In general, the pupil that reacts slowly to light is the abnormal one.

Visual acuity and visual fields should be carefully tested; ipsilateral optic nerve injury may result in a relative afferent pupillary defect and vision loss. Relative afferent pupillary defect is elicited with the swinging flashlight test; the pupil will show decreased constriction to direct illumination, but will constrict normally when the contralateral eye is illuminated.

Next, test the extraocular movements. Normal extraocular movements make a third nerve palsy very unlikely. If extraocular movements are affected, the third nerve palsy should be further investigated, as described later in this article. With normal eye movements, the next step is to exclude a pharmacologic cause. A careful history directed at any inadvertent exposures to mydriatics is essential. Some authors recommend instilling topical 1% pilocarpine into the affected eye; in the case of pharmacologic blockade by parasympatholytics (scopolamine, atropine), the pupil will not constrict; in the case of third nerve palsy, the pupil will constrict briskly. In the case of mydriasis caused by sympathomimetics, the pupil will also constrict, but these patients also should have blanched conjunctivae and a retracted upper eyelid (10).

Next, perform a careful slit-lamp examination. Structural abnormalities of the iris and anterior chamber can cause acute sphincter dysfunction, and usually present with a history of ocular trauma, visual loss, or eye pain. Slit lamp examination may reveal sphincter tears. Intraocular pressure should be measured to exclude angle-closure glaucoma.

If the preceding diagnostic steps have been performed and no definite etiology has been determined, the patient may have a tonic pupil. Adie's tonic pupil syndrome is believed to be a defect affecting parasympathetic pupil fibers after they leave the ciliary ganglion.

Question 2: Is This an Isolated CN III Palsy?

CN III is most often affected in combination with other cranial nerves, particularly II, IV, V, and VI. An understanding of the anatomy of the third nerve can help identify neurological deficits that frequently accompany CN III palsy. A careful cranial nerve examination, in conjunction with a general neurological examination (including observing the patient's gait), will differentiate an isolated CN III palsy from the more common situation where multiple neurological deficits are present.

Midbrain/Brainstem

The nerve begins with a cluster of nuclei near the center of the midbrain, at the level of the superior colliculus; nerve fascicles exit ventrally through the brainstem into the interpeduncular cistern ([12] and [13]). Isolated CN III palsy has been reported from brainstem lesions, but lesions in this region usually affect surrounding cerebellar or brainstem structures, and cause a number of syndromes: Weber's syndrome (CN III palsy with contralateral limb weakness), Benedikt's syndrome (CN III palsy with contralateral cerebellar tremor), Nothnagel's syndrome (CN III palsy with cerebellar ataxia), or internuclear ophthalmoplegia (adduction weakness with contralateral nystagmus upon abduction) ([14], [15], [16] and [17]). Infarction, arteriovenous malformation, cavernous hemangioma, neoplasm, multiple sclerosis, and traumatic injury have been implicated in this type of lesion ([18] and [19]).

Subarachnoid Space

In the subarachnoid space of the interpeduncular cistern, the nerve passes the basilar artery, superior cerebellar artery, and travels in close proximity to the posterior communicating artery (Figure 2). Because there are few other neural structures in this area, aneurysms of the posterior communicating artery, basilar artery, and superior cerebellar artery tend to cause an isolated CN III palsy.

Cavernous Sinus

The nerve then enters the cavernous sinus, where it is in close proximity to nerves IV, V, VI, and the carotid artery (20). Lesions in this region (cavernous sinus thrombosis, carotid artery aneurysms) typically involve some combination of III, IV, V, or VI palsy, along with evidence of impaired venous drainage from the eye (chemosis or proptosis).

Orbital Apex

In the cavernous sinus, the nerve divides into superior and inferior divisions, then enters the orbital apex through the superior orbital fissure, where it travels with the optic nerve, ophthalmic artery, nerve VI, and the nasociliary branch of V1 (21). Lesions affecting CN III in the orbital apex are usually accompanied by facial numbness (superior division of CN V) and visual loss (CN II) (22).

Question 3: What is the Risk of Intracranial Aneurysm with Isolated CN III Palsy?

The key issue to address for a patient presenting with CN III palsy is whether or not the palsy is caused by an intracranial aneurysm. Several recent studies have clarified the natural history of unruptured intracranial aneurysms: the 5-year risk of rupture is highly variable (between 0% and 50% per year), and depends on size and location of the aneurysm. The aneurysms with the highest rates of rupture (posterior communicating and basilar tip aneurysms) are also the aneurysms most likely to cause an isolated CN III palsy; these posterior circulation aneurysms have a rate of rupture between 2.5% and 50%, depending upon the size of the aneurysm (23). In addition, cranial nerve palsy from an aneurysm likely reflects an acute change (hemorrhage or expansion) in the aneurysm; these aneurysms may have a higher risk of rupture. When intracranial aneurysms rupture, the subsequent mortality and morbidity are extremely high. A large percentage of patients die from the initial rupture, and the rest (up to 70% in some series) experience significant morbidity from rebleeding or subsequent vasospasm and stroke ([24], [25], [26] and [27]). Although some debate exists about the best strategy for management of unruptured but symptomatic intracranial aneurysms, it is a diagnosis that carries significant risk, and should be established or excluded with urgency (28).

CN III dysfunction can be classified according to whether the pupil is involved (pupil-involving or pupil-sparing) and the degree of extraocular muscle dysfunction (partial or complete). This distinction is important because it has long been held that when an aneurysm (or other compressive lesion) is the cause of third nerve palsy, the pupil will almost always (95–97% of the time) be involved; this has become known as “the rule of the pupil” ([1] and [31]). The anatomic basis of the rule of the pupil is the arrangement of the pupillary constrictor fibers within the subarachnoid portion of the nerve. Fibers that supply the pupillary constrictors are located superficially in the dorsomedial aspect of the nerve (Figure 2), and are readily compressed by an aneurysm arising from the posterior communicating artery (32).

In early retrospective case series, there seems to be a subset of third nerve palsies that do not involve the pupil at all, and occur mainly in people with diabetes, hypertension, or with other vasculopathic risk factors ([33] and [34]). These cases of CN III palsy tend to resolve over time, and are attributed to pathologic changes in the vasa nervorum and ischemic injury to the axons located deeper within the nerve bundle.

Thus, the rule of the pupil came to mean that patients with pupil-sparing CN III palsy, particularly those over age 50 years with vasculopathic risk factors, could safely be managed with outpatient observation, and without cerebral angiography. This type of pupil-sparing CN III palsy has become known as “diabetic third nerve palsy.” The mechanism of this type of CN III palsy is not well delineated, but pathological studies have revealed arteriolar thickening and demyelinating lesions consistent with microvascular ischemia of the nerve ([35] and [36]).

The “rule of the pupil” has an important caveat: there have been numerous cases of incomplete CN III palsies caused by aneurysms that do not involve the pupil ([2], [38], [39], [40] and [41]). These partial extraocular palsies are likely due to the fact that initially an aneurysm (in particular a basilar apex aneurysm) may not compress the supero-medial aspect of the nerve where the pupillary fibers travel. Many partial oculomotor palsies that initially seem to spare the pupil will eventually go on to involve the pupil (33).

Trigeminal Neuralgia

Facial Nerve Paralysis (Bell's Palsy)

7th CN, post-infection, stapedius, lacrimation (epiphora-tears pooling on cheek), facial paralysis, anterior 2/3 of tongue, abnormally acute hearing. Always think of lyme.

Bell’s phenomenon-upward rolling of eyes when attempting to close lids. Palpate parotid for swelling. Usually complete recovery in 1 month.

one of the more sensitive signs is that the patient may be able to blink both eyes, but will not be able to wink the affected eye in a Bell's

Clinical characteristics of typical Bell's palsy include the following: peripheral CN VII dysfunction involving all distal branches; sudden onset with maximal facial weakness usually reached within several days; impaired result on acoustic reflex test in 90 percent; viral prodrome in 60 percent; numbness or pain of the ear, tongue, or face in 50 percent; chorda tympani nerve appears red in 40 percent; reduction in ipsilateral tearing or salivary flow in 10 percent; and spontaneous improvement within 6 months.(Otolaryngol Clin North Am 1991;24(3))

Prednisone 60 mg x 5, then 5 mg/day x 5 days or 1 mg/kg x 7 days with/without a taper

acyclovir 400–800 mg orally five times daily for 10 days. The newer oral antiviral agents such as valacyclovir and famciclovir have better oral absorption, are better tolerated, and have been recommended as alternatives to acyclovir (Valtrex 1g BID)

non-randomized trial use both within three days and get better outcomes than prednisone alone (Hato, N., et al, Otol Neurotol 24(6):948, November 2003)

Emergency physicians frequently encounter patients that present to the ED with facial nerve palsy. The vast majority of patients who have a seventh nerve paralysis will have clinical Bell’s palsy. The following pearls need to be kept in mind:

• Slowly progressive facial paralysis is suggestive of a neoplasm.

• Recurrent unilateral paralysis may occur with Bell’s palsy but is frequently (30%) seen in tumor patients.

• Simultaneous bilateral facial paralysis excludes Bell’s palsy as a diagnosis and is suggestive of Lyme disease.

• Patients who have facial muscle paresis with intact forehead movement should be considered to have an upper motor neuron lesion until proven otherwise.

• Lyme disease must be considered a possible cause, especially in endemic regions.

METHODS: The author of this paper, from the British series of "best evidence topic reports," performed a review of the literature to identify studies of the effect of acyclovir on functional recovery in patients with Bell's palsy. Two of 49 papers that were identified were felt to provide the best evidence regarding this topic.

RESULTS: In one study, 119 patients presenting within 72 hours after the onset of palsy were randomized to a ten-day course of acyclovir (2000mg daily) and prednisolone (1mg/kg for five days tapered to 10mg/day), or prednisolone alone. The combination treatment exhibited a small beneficial effect in the outcomes of motor recovery on visual assessment and partial nerve degeneration on electrical testing. In the second study, 113 patients presenting within 96 hours after the onset of palsy were randomized to a ten-day course of acyclovir (2400mg daily) or a 16-day course of prednisolone (1mg/kg for first ten days). In this study prednisolone was found to have a beneficial effect on the aforementioned outcomes. Neither study included an intention-to-treat analysis. A substantial number of patients was lost to follow-up, and there was no real placebo control group in the second study.

CONCLUSIONS: The available evidence provides no support for the use of acyclovir as monotherapy in patients with Bell's palsy, and suggests that a combination of prednisolone plus acyclovir might have a small benefit in terms of functional recovery when compared with prednisolone alone.

May offer benefit in the long term for full recovery Valtrex 1 g tid for 1 week and prednisone 50 mg OD for 1 week (Ann Otol Rhono Laryngol 112:197, 2003)

Recurrent or bilateral facial palsy should prompt consideration of myasthenia gravis or lesions where the facial nerve exits the pons; such types of palsy occur in lymphoma, sarcoidosis, and Lyme disease (NEJM, 9/23/04, pg. 1323).

Treatment of Bell's Palsy - The Latest
from emedhome.com

Treatment of Bell's palsy remains controversial and variable. The detection of herpes simplex virus in the endoneural fluid of patients with Bell's palsy suggests an association between herpes infection and the onset of facial paralysis (1). Corticosteroids and antiviral agents are commonly prescribed separately and in combination, although evidence of their effectiveness is weak. Two recent Cochrane reviews assessed the effectiveness of corticosteroids and antiviral agents in patients with Bell's palsy and independently concluded that insufficient data exist to support the use of either or both therapies (4,5).

A large, randomized, controlled trial of the efficacy of treatment for Bell's palsy appears in the current issue of the New England Journal of Medicine (2). The study confirmed the generally favorable outcome for patients receiving double placebo, with 65% of patients fully recovered at 3 months and 85% at 9 months. Early treatment (within 72 hours of symptom onset) with prednisolone increased these rates to 83% and 94%, respectively. Acyclovir produced no benefit over placebo, and there was no benefit in its addition to prednisolone. In the US, oral prednisone (1 mg/kg for 7 - 10 days) is typically prescribed (3).

The accompanying editorial notes that although acyclovir does not appear to be of benefit, valacyclovir in combination with glucocorticoids could still be considered in patients with severe or complete facial palsy (3). Valacyclovir is a prodrug that is nearly completely converted to acyclovir and L-valine and has substantially increased bioavailability, as compared with acyclovir. A recent study suggests that the use of valacyclovir in combination with glucocorticoids should be considered in patients with severe or complete facial palsy; there is expert opinion that agrees with this view, noting that there likely is no benefit of antiviral therapy in patients with moderate palsy (3,6).

No good data are currently available regarding how best to treat patients who present more than 72 hours after the onset of symptoms (2).

References:

(1) Murakami S, at al. Bell palsy and herpes simplex virus: identification of viral DNA in endoneurial fluid and muscle Ann Intern Med 1996;124:27-30.
(2) Sullivan FM, et al. Early treatment with prednisolone or acyclovir in Bell's palsy N Engl J Med 2007;357:1598-1607.
(3) Gilden DH, et al. Bell's palsy - is glucocorticoid treatment enough? N Engl J Med 2007 Oct 18;357(16):1653-5.
(4) Salinas RA, et al. Corticosteroids for Bell's palsy (idiopathic facial paralysis) Cochrane Database Syst Rev 2004;4:CD001942-CD001942.
(5) Allen D, et al. Aciclovir or valaciclovir for Bell's palsy (idiopathic facial paralysis) Cochrane Database Syst Rev 2004;3:CD001869-CD001869.
(6) Hato N, et al. Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study Otol Neurotol 2007;28:408-413.

Patients with hypertension, impaired taste, pain other than in the ear, and complete facial weakness all carry a poor prognosis (ACP Journal Club, March/April, 2008, pg. 29).

Abstract
BACKGROUND: Previous trials of corticosteroid or antiviral treatments for Bell`s palsy have been underpowered or have had insufficient follow-up. The aim of this study was to compare the short-term and long-term effects of prednisolone and valaciclovir in the recovery of the affected facial nerve in a large number of patients. METHODS: In this randomised, double-blind, placebo-controlled, multicentre trial, patients aged 18 to 75 years who sought care directly or were referred from emergency departments or general practitioners within 72 h of onset of acute, unilateral, peripheral facial palsy, between May, 2001, and September, 2006, were assessed. Patients were randomly assigned in permuted blocks of eight to receive placebo plus placebo; 60 mg prednisolone per day for 5 days then reduced by 10 mg per day (for a total treatment time of 10 days) plus placebo; 1000 mg valaciclovir three times per day for 7 days plus placebo; or prednisolone (10 days) plus valaciclovir (7 days). Follow-up was for 12 months. The primary outcome event was time to complete recovery of facial function, as assessed with a regional Sunnybrook scale score of 100 points. Analysis was by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT00510263. FINDINGS: Of 839 patients who were randomly assigned, 829 were included in the modified intention-to-treat analysis: 206 received placebo plus placebo, 210 prednisolone plus placebo, 207 valaciclovir plus placebo, and 206 prednisolone plus valaciclovir. Time to recovery was significantly shorter in the 416 patients who received prednisolone compared with the 413 patients who did not (hazard ratio 1.40, 95% CI 1.18 to 1.64; p<0.0001). There was no difference in time to recovery between the 413 patients treated with valaciclovir and the 416 patients who did not receive valaciclovir (1.01, 0.85 to 1.19; p=0.90). The number of patients with adverse events was similar in all treatment arms. INTERPRETATION: Prednisolone shortened the time to complete recovery in patients with Bell`s palsy, whereas valaciclovir did not affect facial recovery.

"Peripheral" Facial N. Palsy - Are You Sure It Is Benign?
(EMEDhome)
Facial nerve palsy is frequently encountered by Emergency Physicians. Common teaching states that with a central cause of facial nerve palsy (i.e. stroke) there is no loss of function of the upper muscles of facial expression; a peripheral facial palsy is diagnosed by weakness of all muscles of facial expression and is most commonly from an idiopathic Bell's palsy.

However, it is important to recognize that weakness from a "peripheral" facial nerve palsy resulting in weakness of the forehead musculature can also be produced by a brainstem lesion within the pons. Although it appears paradoxical that a "central" lesion in the pons produces peripheral facial weakness, the nomenclature is not likely to change. Facial nerve palsy from a central pontine lesion is often - but not always - associated with additional neurologic symptoms and signs (e.g. other CN findings).

The clinician, then, should not be fooled that apparent facial nerve palsy is benign simply because the forehead is not spared - especially if the presentation is atypical, for example, the patient has vestibular signs ("dizziness") or if the patient has a history of diabetes or a hypertension - groups at higher risk for pontine infarctions.

References:
(1) Sherman SC, et al. Pontine hemorrhage presenting as an isolated facial nerve palsy Ann Emerg Med 2005;46: 64-6.
(2) Gilden DH. Clinical practice. Bell's Palsy N Engl J Med 2004;351:1323-31.

Newest MA (JAMA. 2009;302(9):985-993. ) says definitely steroids, maybe anti-virals

Ramsay Hunt Syndrome

Central Venous Thrombosis

Multiple Sclerosis (MS)

characterized by lesions separated in space and time. Internucleur opthalmoplegia-can’t adduct eye, c nystagmus

Cranial Nerve Disorders

3rd Nerve Palsy

Differentiating Third Nerve Palsy from Other Causes of the Isolated Dilatated Pupil