The brain stem consists of the midbrain, pons, and medulla. Brain stem infarction commonly occurs due to an embolus occluding large arteries (vertebral or basilar arteries) supplying it or due to an embolus traveling from the heart, or atherosclerotic plaques from the large arteries (vertebral, basilar) [1]. Brainstem infarcts are relatively less common as compared to hemispheric infarcts [2]. The common clinical presentation is sudden onset focal neurological deficits like hemiparesis, vertigo, orthostatic symptoms, diplopia, and lower cranial nerve paralysis with dysphagia, and hoarseness. Vertigo is the cardinal feature of brain stem infarction [2] followed by ipsilateral cranial nerve symptoms, contralateral hemiplegia, hemianesthesia (crossed motor or sensory signs) with bilateral involvement of the sensory tract or motor tract or both.

A few uncommon clinical features of brain stem infarction include "salt and pepper" facial pain [3], blepharospasm [4], palatal myoclonus [2], hiccough [5], tinnitus in medullary infarction [6], bruxism and trismus in basilar artery occlusion [7], and peduncular hallucinosis in midbrain infarction [8]. If there is total occlusion of the vertebrobasilar system then patients can present with tachycardia, fluctuating blood pressure, ataxia, impaired consciousness, and coma leading to death. Pontine or midbrain infarction can also present as "locked-in syndrome" in which the affected individual has sudden onset vomiting, transient loss of consciousness with quadriplegia, bilateral facial palsy, anarthria (total loss of articulation), and bilateral oculomotor nerve palsy resulting in loss of voluntary eye movements [2].

Clinical features specific to the ischemic involvement of the different regions of the brainstem are:

Midbrain: ipsilateral oculomotor (3rd cranial nerve) paralysis with contralateral hemiplegia (Weber syndrome)

Pons: 5th, 6th, 7th and 8th cranial nerve involvement, diplopia, dysarthria, vertigo, gait abnormality, and/or sensation of ear canal block, sustained horizontal nystagmus, conjugate eye movements when the gaze is directed towards the side of hemiparesis [6], ataxic hemiparesis.

Medulla: 9th, 10th, 11th and 12th cranial nerve involvement, pure motor hemiparesis if the medullary pyramid is the site of the infarction; sensory motor hemiplegia if the medial lemniscus is involved; or Dejerine syndrome wherein there is ipsilateral tongue paralysis with contralateral hemiplegia. A patient presenting with acute onset vertigo and then developing sudden respiratory failure is likely to have a medullary infarct.

• Periodic Breathing

  Nocturnal periodic breathing at altitude of 6.300 and 8.050 m. J Appl Physiol, 61 (1986), pp. 280-287 Copyright © 1999. Sociedad Española de Neumología y Cirugía Torácica [archbronconeumol.org]

  Oku Y, Okada M (2008) Periodic breathing and dysphagia associated with a localized lateral medullary infarction. Respirology (Carlton, Vic.) 13: 608–610. View Article Google Scholar 57. [journals.plos.org]

• Miosis

  It is typified by vertigo, ipsilateral hemiataxia, dysarthria, ptosis and miosis. Most patients with this stroke recover very well and often resume their previous activities (Nelles et al, 1998). [tchain.com]

  Neurological examinations showed left ptosis and miosis, hoarseness, dysphagia, right mild hemiparesis, left ataxia of his extremities, and truncal ataxia. He also had hypalgesia/hypotemperature on his right side. [hindawi.com]

  […] the distribution of the 5th cranial nerve (this nucleus is a long vertical structure that extends in the lateral aspect of the pons down into the medulla) Sympathetic pathway : ipsilateral Horner’s syndrome, that is partial ptosis and a small pupil (miosis [lifeinthefastlane.com]

  […] ophthalmoplegia Nystagmus (skew deviation, see-saw, convergence-retraction) Ocular tilt reaction (skew) Eyelid and pupil abnormalities: Horner syndrome typically presents with ispilateral partial, mild, ptosis (drooping or falling of upper eyelid), miosis [eyewiki.aao.org]

  Ipsilateral clinical features include the following: Ataxia and dysmetria, due to damage to the inferior cerebellar peduncle and cerebellum Horner syndrome (eg, ptosis, miosis, hypohidrosis or anhidrosis, enophthalmos), due to damage to descending sympathetic [emedicine.medscape.com]

• Dizziness

  Two days after discharge from the hospital he was admitted to the neurological department in the university hospital with dizziness, hickups, reduced sensitivity of the right side of face and trunk. [relis.no]

  A person may have vertigo, dizziness and severe imbalance without the hallmark of most strokes — weakness on one side of the body. The symptoms of vertigo dizziness or imbalance usually occur together; dizziness alone is not a sign of stroke. [stroke.org]

  Two days after his first visit, he reported dizziness, speech disturbance, clumsiness of his right extremities, and gait disturbances. [hindawi.com]

  He had high blood pressure and was driving home from work and felt very dizzy. He drove to his doctors office where they called an ambulance and he was taken to the emergency room. [bmj.com]

• Nystagmus

  In the author's experience, these patients often exhibit rebound nystagmus, which is a variant of gaze-evoked nystagmus. Some of these patients have upbeating nystagmus supine, often confused with BPPV. [dizziness-and-balance.com]

  In the author's experience, these patients often exhibit rebound nystagmus, which is a variant of gaze-evoked nystagmus. [tchain.com]

  The brainstem including the medulla also contains vestibular-otolith pathways and the ocular sympathetic pathway which can produce skew deviation, nystagmus, or Horner syndrome respectively. [eyewiki.aao.org]

  […] oculomotor (3rd cranial nerve) paralysis with contralateral hemiplegia (Weber syndrome) Pons: 5th, 6th, 7th and 8th cranial nerve involvement, diplopia, dysarthria, vertigo, gait abnormality, and/or sensation of ear canal block, sustained horizontal nystagmus [symptoma.com]

• Cranial Nerve Involvement

  Clinical features specific to the ischemic involvement of the different regions of the brainstem are: Midbrain: ipsilateral oculomotor (3rd cranial nerve) paralysis with contralateral hemiplegia (Weber syndrome) Pons: 5th, 6th, 7th and 8th cranial nerve [symptoma.com]

  Clinically, in localizing strokes to the brainstem one looks for the "cardinal" feature of an ipsilateral peripheral cranial nerve involvement, and a contralateral weakness or sensory deficit. Cerebellar signs, if present, should be ipsilateral. [tchain.com]

  Contra pain and temp Vascular - Pica or vertebral Symptoms of brainstem stroke Clinically, in localizing strokes to the brainstem one looks for the "cardinal" feature of an ipsilateral peripheral cranial nerve involvement, and a contralateral weakness [dizziness-and-balance.com]

• Upbeat Nystagmus

  In the author's experience, these patients often exhibit rebound nystagmus, which is a variant of gaze-evoked nystagmus. Some of these patients have upbeating nystagmus supine, often confused with BPPV. [dizziness-and-balance.com]

  Upbeat nystagmus may occur. Small vessel disease (diabetes, hypertension, hypercholesterolemia) is the usual cause. Pontine hyperintense lesions. It is fairly common to encounter areas of increased signal on T2 MRI in the pons. [tchain.com]

• Crossed Hemiplegia

  Neurology 1996:47:1141-1147 Named Brainstem Syndromes Eponym Site Cranial Nerves Tracts Signs Usual Cause Weber Base of Midbrain III Corticospinal Oculomotor palsy with crossed hemiplegia Vascular, tumor Claude Midbrain tegmentum III Red nucleus and Brachium [tchain.com]

  Eponym Site Cranial Nerves Tracts Signs Usual Cause Weber Base of Midbrain III Corticospinal Oculomotor palsy with crossed hemiplegia Vascular, tumor Claude Midbrain tegmentum III Red nucleus and Brachium Conjunctivum Oculomotor nerve, contralateral hemiplegia [dizziness-and-balance.com]

The aim of the workup is to determine the characteristics of the vascular lesion and the etiology of the brain stem infarction. A detailed history during workup provides clues to the risk factors and etiology of the condition while a thorough neurological, cardiovascular, and bedside glucose testing are mandatory to determine further workup and management.

Computed tomography scanning (CT) is performed first to differentiate between an ischemic infarct and hemorrhagic stroke as it has 95% sensitivity in identifying hemorrhage especially if done within 24 hours of onset of symptoms [9] [10]. Occluded and dolichoectatic arteries can be identified better with spiral CT angiography [11] [12]. Magnetic resonance imaging (MRI) has greater sensitivity than CT in the identification of ischemia with small lacunar infarcts being seen only on MRI. Diffusion-weighted MRI is highly sensitive for early ischemia and should be ordered after the CT scan. MRI and magnetic resonance angiography (MRA) are useful in detecting dissection, demyelinating plaques, vertebrobasilar dolichoectasia, and dissection. [13] [14] [15].

In addition, other tests are indicated based on the clinical evaluation to detect the etiology and risk factors of the brainstem infarct:

Cardiac factors: electrocardiography (in all cases), telemetry or holter monitoring, serum troponin (in cases suspected to have myocardial ischemia), and echocardiography [16] especially in patients under 45 years of age or in those with basilar artery occlusion.

Vascular factors: blood tests to rule out thrombotic disorders (homocysteine levels, antiphospholipid antibodies, protein S, protein C, antithrombin III, factor V Leiden) and routine tests like complete blood count, platelet count, PT/PTT, fasting blood glucose, lipid profile, and serology for syphilis.

Autoimmune factors: antinuclear antibodies, rheumatoid factor, erythrocyte sedimentation rate.

Urine toxicology and drug screening for stimulants like cocaine and amphetamines.

We fully realize that early and appropriate treatment are essential to improve the treatment results, and constructing a medical system with a team of orthopedists, radiologists, and neurosurgeons is also very important. [ncbi.nlm.nih.gov]

It is not intended as medical advice for individual conditions or treatments. [drugs.com]

1 Endoscopic surgical treatment of Cushing's disease: A single-center experience of cauterization of peritumoral tissues. 61 31777545 2019 2 [Catheter balloon dilation combined with acupuncture for cricopharyngeal achalasia after brain stem infarction [malacards.org]

Fortunately, fast treatment and beginning of the recovery process as soon as possible can make a significant difference in the well-being of a patient after a brainstem stroke. [saebo.com]

Preceding TIAs, blood pressure level, serum cholesterol and triglyceride values, and aortic arch angiogram findings, on the other hand, had no effect upon the prognosis. The effects of body build on prognosis remained obscure. [ncbi.nlm.nih.gov]

The majority of patients had a benign prognosis. [journals.sagepub.com]

Results Overall, 14 (45.2%) patients had a good prognosis, 13 (41.9%) patients had a poor prognosis, and four (12.9%) patients died. Dysphagia, vomiting, cranial neuropathy, and high NIHSS score on admission were associated with a poor outcome. [sjamf.eg.net]

[…] they carry a poor prognosis. 2 Reply [dailyrounds.org]

Prognosis for Stroke Patients The prognosis for stroke patients varies dramatically between individuals. The most important factor in a patient’s brain stem stroke prognosis is time. [guidedoc.com]

The aim of the workup is to determine the characteristics of the vascular lesion and the etiology of the brain stem infarction. [symptoma.com]

The etiologic mechanisms of brain stem infarction in this anomaly are discussed. The tortuosity and dilatation of the basilar artery were thought to play an important role in the pathogenesis of the brain stem infarction. [ncbi.nlm.nih.gov]

Our results suggest that a single brainstem lesion constitutes a syndrome of multiple etiologies, and that these etiologies and prognoses can differ widely. [journals.sagepub.com]

• Small vessel disease is the prime etiology in thalamic infarcts. • The etiology of midbrain infarcts remains undetermined in up to 50% of cases. [medlink.com]

Epidemiology 1998; 9(6): 596-600. [relis.no]

Appel LJ, Braun LT, Chaturvedi S, Creager MA, Culebras A, Eckel RH, Hart RG, Hinchey JA, Howard VJ, Jauch EC, Levine SR, Meschia JF, Moore WS, Nixon JV, Pearson TA; American Heart Association Stroke Council; Council on Cardiovascular Nursing; Council on Epidemiology [passeportsante.net]

[Epidemiology of stroke in the elderly : “the silver tsunami”]. Rev Prat, 62(9), 1221-1224. Kim, J. S., & Lee, H. (2009). Inner Ear Dysfunction Due to Vertebrobasilar Ischemic Stroke. [Article]. [hearinghealthmatters.org]

The investigators found the greatest risk of subsequent stroke to be in those individuals with a combination of low blood flow and blood pressure below 140/90 mm Hg. [6] Epidemiology of Vertebrobasilar Stroke The frequency, incidence, and prevalence of [emedicine.medscape.com]

However, epidemiological data have shown a high prevalence of central sleep apnea in patient groups with heart involvement. Depending on the NYHA classification and the diagnostic methods, it varies around 40 to 60% [59] or even more [60]. [journals.plos.org]

The pathophysiological background and potential therapeutic strategies are discussed. [ncbi.nlm.nih.gov]

Central sleep apnoea in Arnold-Chiari malformation: evidente of pathophysiological heterogeneity. Eur Respir J, 12 (1998), pp. 1.482-1.485 [12.] M. Gunel, I.A. Awad, K. Finberg, H.H. Batjer, T.A. Kopitnik, L. Morison, et al. [archbronconeumol.org]

Cigolini M Cappellari F Hypertensive brain stem encephalopathy: clinically silent massive edema of the pons Neurol Sci 2001 22 317 320 6 Fugate JE Rabinstein AA Posterior reversible encephalopathy syndrome: clinical and radiological manifestations, pathophysiology [jkna.org]

The pathophysiology of otologic facial paralysis. Otolaryngol Clin North Am1974;7:309–30. ↵ Launay M, Fredy D, Merland JJ, et al. Narrowing and occlusion of arteries by intracranial tumors. Review of the literature and report of 25 cases. [jnnp.bmj.com]

In Barnet HJM (and others, Eds), Stroke: Pathophysiology, Diagnosis and Management. New York: Chrchill-Livingstone, pp 549-619, 1986 Dai, A. I. and M. Wasay (2006). "Wernekink comissure syndrome: a rare midbrain syndrome secondary to stroke." [dizziness-and-balance.com]

Even if laryngeal penetration and pulmonary aspiration are observed, chest infection could be prevented by swallowing exercise combined with voluntary cough. [ncbi.nlm.nih.gov]

Ask your caregiver for more information about preventing pressure sores. Things that you can do to help prevent a brainstem infarction: Do not smoke. Do not smoke tobacco products, or use illegal (street) drugs. [drugs.com]

Proper care or preventing these issues can greatly lower your risk of stroke. [winchesterhospital.org]

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