Cerebral Infarction as a Rare Complication of Wasp Sting

INTRODUCTION

Wasps, bees, and hornets belong to the order of insects called “Hymenoptera.” Millions of cases of Hymenoptera stings happen every year around the world. Frequently, they are accompanied by local inflammatory reactions. Less commonly, victims develop severe systemic allergic reactions presenting with hypotension or anaphylactic shock, generalized edema, respiratory failure, or even multiple organ failures. Although rare, neurological complications including stroke have been reported (Table 1). In this paper, we present a case of ischemic stroke 30 min after a wasp sting, and a systematic review of the literature.

Table 1. Case Reports on Ischemic Stroke and Other Associated Neurological Manifestations Following Bee/Wasp Bite.

	Presentation	Number of stings and location / Time interval between sting and stroke symptoms	Imaging findings	Outcome	Other complications
Schiffman, et al.[1]	57 years old with left homonymous hemianopia followed by unresponsiveness	30–40 bee sting on head, face, neck and right arm / 2 days	MRI & CT – right occipital ischemic infarct followed with a large right temporo-occipital hemorrhagic infarct	Partial improvement of visual field loss	Ischemic optic neuropathy, hemorrhagic stroke
Crawley et al.[2]	30-year old with anaphylaxis and respiratory failure after a wasp sting. Right homonymous superior quadrantanopia after 36 hours	Single wasp sting / 36 hours	CT – left occipital infarction	Full recovery	Anaphylaxis, respiratory failure
Riggs et al.[4]	52-year old with anaphylactic shock 2 min after a wasp sting followed by slurred speech and left hemiparesis a few hours later	Single wasp sting / a few hours	MRI – diffuse bilateral hemisphere stroke MRA – complete right internal carotid artery and near complete left internal carotid artery occlusion	Noto reported	Seizure, anaphylactic shock
Rajendiran et al.[5]	25-year old with left hemiparesis and transient visual loss	Multiple bee stings on head and neck / not reported	MRI – right parietal and basal ganglia infarct	Complete motor and vision recovery in 8 months	None
Wani et al.[6]	40-year old with right hemiparesis, and severe multi-organ dysfunction.	>50 wasp stings entire body / 16 hours	MRI – multiple ischemic lesions in bilateral cerebral hemispheres, pons, bilateral thalami, and left parieto-occipital region.	Vegetative state	Anaphylaxis, multiorgan failure
Temizoz et al., 2009[7]	60-year old developed a left sided hemiplegia and dysarthria	Multiple bees stings entire body / 2 hours	MRI – ischemic changes in the frontal lobes, right temporoparietal area, and bilateral centrum semiovale	Residual hemiparesis after three months	None
Sachdev et al., 2002[8]	40-year old with left hemiplegia and right facial droop	Single wasp sting on face / 10 hours	MRI – right ventral pons, and right cerebellum infarction	Complete motor recovery within 5 days. Some improvement of cerebellar function and dysarthria after two months	None
Stalin Viswanathan et al., 2012 [9]	59-year old with dysarthria, left sided upper motor neuron facial nerve palsy, left hemiplegia and left conjugate gaze palsy	Multiple bees sting entire body / 2 hours	MRI – right MCA territory infarct	Complete resolution of dysarthria and cranial nerve deficits with significant recovery from the left hemiplegia after two weeks	Seizure
J. MURRAY DAY, 1962[10]	36-year old with confusion and right hemiplegia	Multiple yellow jackets stings over the neck, face and arms / 15 minutes	Not reported	several generalized convulsions and hemodynamic instability within few hours followed by decerebration, intracerebral hemorrhage, and death within 30 hours after the stings	Seizure, intracerebral hemorrhage, and death
Mukund R. Vidhate et al., 2011[11]	8 years old with left hemiplegia and altered mental status followed by right hemiplegia, ophthalmoplegia, and partial left ophthalmoplegia	Not reported	CT: non-hemorrhagic infarcts in left frontoparietal and bilateral subcortical regions and bilateral cavernous sinus thrombosis MRI: infarcts in the left frontoparietal cortex, posterior limb of internal capsule, and right subcortical region	resolution of encephalopathy and some improvement in left hemiplegia with persistence right ophthalmoplegia 15 days after admission	Orbital cellulitis, bilateral cavernous sinus thrombosis
Romano JT, et al.,1989[12]	34 months old with dysarthria and right hemiparesis	Single yellow jacket’s sting on the inner side of his upper lip / 4 days	CT – left putamen and caudate ischemic infarct Angiography – left supraclinoid internal carotid artery occlusion	NR	None
Weeranun Dechyapirom et al.,2010[13]	64-year old with left hemiparesis and heart attack	Multiple bee stings on face, neck, chest, and upper extremities / 16 hours	MRI: Large right MCA territory ischemic stroke	Complete neurological recovery within a week	Non ST-elevated myocardial infarction
De-Meing Chen et al., 2004[14]	71-year old woman with left hemiplegia followed by paraplegia.	Multiple wasps entire body / 24 hours	Arteriography – total occlusion of the infrarenal aorta Two weeks later, CT – right MCA territory infarction	Partial recovery	Infrarenal aortic artery occlusion

CASE PRESENTATION

A 53-year old Caucasian man was stung by a wasp on his right hand while he was working in his garage. Initially, there was just local pain and inflammation without any systemic reaction. Thirty minutes later, while he was sitting on a chair, he noticed that his left upper limb became numb and started moving out of his control. He presented to our emergency department.

Past medical history was significant for multiple sclerosis which was diagnosed in 2002 and has been inactive since, coronary artery disease with myocardial infarction and angioplasty in 2012, hypertension, and hyperlipidemia. His home medication included daily lisinopril 20 mg and intermittent use of daily aspirin 81 mg. He denied any history of smoking or alcohol consumption. Family history was negative for stroke.

In the emergency department, the examination revealed a slightly overweight man, afebrile, with normal blood pressure and respiratory rate, and mild tachycardia with a normal level of consciousness. Lungs were clear to auscultation and heart was regular rate and rhythm with no adventitious sounds. No carotid bruit was noted. There were an expected swelling and redness at the sting site on the back of his right hand.

The neurological examination was significant for mild dysarthria, uncontrollable movement of the left hand (alien hand syndrome), decreased sensation to touch, pain, and temperature as well as extinction to double simultaneous stimulation in the entire left upper extremity. We also noticed vertical and horizontal nystagmus as well as ataxic gait and impaired tandem gait, which, according to the patient, were chronic symptoms secondary to his multiple sclerosis.

His initial blood and imaging workup including cell blood count, complete metabolic and coagulation panel, lipid profile, hemoglobin A1c, cardiac enzymes, electrocardiogram, chest x-ray was unremarkable except for a mildly elevated serum creatinine (1.89 mg/dl) and an elevated serum low-density lipoprotein (160 mg/dl) and triglyceride (329 mg/dl). Initial head computed tomography (CT) scan was negative for any acute finding. The magnetic resonance imaging (MRI) study of the brain, obtained within 6 hours, showed two punctate diffusion lesions in the right frontoparietal area consistent with acute cerebral infarction (Figure 1). A magnetic resonance angiography (MRA) of the head and neck was unremarkable. The Doppler ultrasonography of the lower extremities, transthoracic echocardiography and transesophageal echocardiography, and hypercoagulable and vasculitis panel were all unremarkable. A 4-day inpatient telemetry results did not show any atrial fibrillation or other abnormal cardiac rhythm.

Figure 1. Diffusion-weighted image (A) and T2-FLAIR (B) brain MRI showed two punctate ischemic lesions in the right frontoparietal.

He was prescribed aspirin 325 mg and atorvastatin 80 mg daily. The left-hand movement stopped soon after admission; however, there was a mild residual weakness in the left hand. The weakness was completely resolved within 4 days.

DISCUSSION

We found 13 other case reports of ischemic stroke following wasp or bee sting in a systematic literature review on articles published prior to July 2015 in PubMed and Google Scholar with the following search topics: “bees or wasps” and “stroke or cerebral infarction” (Table 1). Age at onset ranged from 34 months to 71 years old. Twenty percent of cases had anaphylactic shock preceding their stroke. The time interval between the sting and the stroke ranged from 15 min to 4 days with a median of 16 hours. On the brain MRI, findings were variable. Ischemic infarcts in the territory of middle cerebral artery were commonly reported. Almost half of the patient recovered completely within 4 days to 8 months. One patient developed intracerebral hemorrhage and died. One patient developed multi-organ failure and progressed to a vegetative state. There was one case of cavernous sinus thrombosis reported in an 8-year old toddler. Eight cases had suffered from multiple stings.

Several pathophysiologies have been postulated in the development of stroke after wasp or bee stings. The major mechanisms include hypotension and hypoxia related to an anaphylactic reaction, enhanced platelet aggregation, thrombogenesis, or vasoconstriction induced by the release of several inflammatory substances after the wasp sting [1]. These substances include serotonin (5-hydroxytryptamine), histamine, dopamine, acetylcholine, bradykinin, leukotrienes, and thromboxane [2, 3]. Intense retrograde stimulation of the superior cervical ganglion resulting in obstruction of the terminal internal carotid artery is also reported to be causing stroke in the cases of wasp sting to the head and neck area [4].

Our patient’s presentation was consistent with “Alien hand syndrome” that can occur in patients with stroke. Although our workup did not show a definite etiology, the etiology of his small diffusion defect in the right frontoparietal cortex was probably embolic. Nevertheless, the patient had some risk factors for stroke including a history of hypertension, hyperlipidemia, and acute coronary syndrome. The temporal relationship between the wasp sting and the development of neurological deficits is likely related. Since no hypotension or allergic reaction was noted in our patient and he was stung only on his hand, it is unlikely that the stroke was related to the retrograde intense activation of the superior cervical sympathetic ganglion or anaphylactic shock and hypotension. We think that the direct vasogenic and thrombogenic effect of the wasp sting was the most likely mechanism leading to stroke in our case.