Myasthenic crisis is a life-threatening condition commonly associated with respiratory failure and may present in unusual ways. However, there is paucity in the literature about the cardiac manifestations of myasthenia gravis. We present a case of a 61-year-old male who presented to the emergency room with upper respiratory infection symptoms who soon thereafter suffered sudden cardiac arrest. He was found to have shortened PR interval pre and post arrest onelectrocardiogram (EKG). Only past medical history, discovered post cardiac arrest, was myastenia gravis. All other causes of cardiac arrest were ruled out, and it was deemed to be due to a manifestation of myastenia gravis. The patient was treated with intravenous steroids and plasmapheresis with resolution of shortened PR interval. It is hypothesized that striatial muscle antibodies may trigger inflammation in cardiac muscle and cause conduction abnormalities. In addition, anti-Kv1.4 antibodies have been associated with EKG abnormalities, including QT prolongation and T-wave inversion. To our knowledge, we are the first to report myasthenic crisis manifesting with isolated cardiac arrest with pulseless electrical activity and a shortened PR interval

Andreev, Alexander

Begum, Farhana

Sahni, Sonu

Singh, Anjuli

English

The Touro College and University System

Touro Scholar Touro College of Osteopathic Medicine (New York) Publications and Research Touro College of Osteopathic Medicine (New York) 2-5-2020 A Broken Heart: Cardiac Arrest As the Initial Presentation of Myasthenic Crisis Alexander Andreev Farhana Begum Anjuli Singh Sonu Sahni Touro College, sonu.sahni@touro.edu Follow this and additional works at: https://touroscholar.touro.edu/tcomny_pubs  Part of the Cardiology Commons Recommended Citation Andreev, A., Begum, F., Singh, A., & Sahni, S. (2020). A Broken Heart: Cardiac Arrest As the Initial Presentation of Myasthenic Crisis. Cureus, 12 (2), 6891. https://doi.org/10.7759/cureus.6891 This Article is brought to you for free and open access by the Touro College of Osteopathic Medicine (New York) at Touro Scholar. It has been accepted for inclusion in Touro College of Osteopathic Medicine (New York) Publications and Research by an authorized administrator of Touro Scholar. For more information, please contact touro.scholar@touro.edu. Received 01/30/2020 Review began 02/02/2020 Review ended 02/02/2020 Published 02/05/2020© Copyright 2020Andreev et al. This is an open accessarticle distributed under the terms ofthe Creative Commons AttributionLicense CC-BY 4.0., which permitsunrestricted use, distribution, andreproduction in any medium, providedthe original author and source arecredited.A Broken Heart: Cardiac Arrest As theInitial Presentation of Myasthenic CrisisAlexander Andreev  , Farhana Begum  , Anjuli Singh  , Sonu Sahni   1. Internal Medicine, Brookdale University Hospital Medical Center, New York, USA 2. Internal Medicine,New York Medical College, Valhalla, USA 3. Research Medicine, New York Institute of Technology Collegeof Osteopathic Medicine, New York, USA 4. Primary Care, Touro College of Osteopathic Medicine, NewYork, USACorresponding author: Alexander Andreev, andreev-am@outlook.comAbstractMyasthenic crisis is a life-threatening condition commonly associated with respiratory failureand may present in unusual ways. However, there is paucity in the literature about the cardiacmanifestations of myasthenia gravis. We present a case of a 61-year-old male who presented tothe emergency room with upper respiratory infection symptoms who soon thereafter sufferedsudden cardiac arrest. He was found to have shortened PR interval pre and post arrest onelectrocardiogram (EKG). Only past medical history, discovered post cardiac arrest, wasmyastenia gravis. All other causes of cardiac arrest were ruled out, and it was deemed to be dueto a manifestation of myastenia gravis. The patient was treated with intravenous steroids andplasmapheresis with resolution of shortened PR interval. It is hypothesized that striatialmuscle antibodies may trigger inflammation in cardiac muscle and cause conductionabnormalities. In addition, anti-Kv1.4 antibodies have been associated with EKG abnormalities,including QT prolongation and T-wave inversion. To our knowledge, we are the first to reportmyasthenic crisis manifesting with isolated cardiac arrest with pulseless electrical activity anda shortened PR interval. Categories: Cardiology, Internal Medicine, NeurologyKeywords: cardiac arrest, short pr interval, myasthenia gravis, conduction abnormalities, myastheniccrisisIntroductionMyasthenic crisis (MC) is a life-threatening condition commonly associated with respiratoryfailure [1]. MC is typically preceded by worsening of other myasthenia gravis (MG) symptoms,including limb, ocular and bulbar muscle weakness. However, there exists a paucity in theliterature about cardiac manifestations of MG. There are isolated reports of possiblearrhythmias and chronic heart disease associated with MG [2]. Herein we present, to the best ofour knowledge, the first case to report MC manifesting with isolated cardiac arrest withpulseless electrical activity (PEA) and a shortened PR interval as the initial presentation of MC.An abstract version of this case was presented at the CHEST Annual Meeting October 19-23,2019 in New Orleans, LA (Andreev A, Singh A, Begum F, Sahni S. Wednesday MedicalStudent/Resident Case Report Posters, https://journal.chestnet.org/article/S0012-3692(19)33523-8/fulltext). Case PresentationA 61-year-old male presented to the emergency room with a three-day history of upperrespiratory infection symptoms including cough, fever and myalgia. At presentation, he did not1 2 1 1, 3, 4 Open Access CaseReport  DOI: 10.7759/cureus.6891How to cite this articleAndreev A, Begum F, Singh A, et al. (February 05, 2020) A Broken Heart: Cardiac Arrest As the InitialPresentation of Myasthenic Crisis. Cureus 12(2): e6891. DOI 10.7759/cureus.6891endorse any limb, ocular or bulbar weakness. Initial physical exam was unremarkable, and vitalsigns were within normal limits. Neurologic exam was also noted to be normal with no focalmuscle weakness. Electrocardiogram (EKG) showed normal sinus rhythm with shortened PRinterval of 96 ms (normal: 120-200ms). Shortly after the presentation, the patient was found tobe unresponsive and pulseless. Telemetry monitoring was indicative of cardiac arrest with PEA.Advanced cardiac life support was initiated, the patient was subsequently intubated andcardiopulmonary resuscitation was continued. Return of spontaneous circulation (ROSC)occurred within seven minutes, and the patient was admitted to the medical intensive care unit(MICU). Post resuscitation EKG showed sinus tachycardia with shortened PR interval, similar toprior. The EKG immediately post cardiac arrest is shown in Figure 1.FIGURE 1: EKG showing normal sinus rhythm with short PRinterval (96 ms) (post cardiac arrest)Laboratory data on presentation were not obtained due to cardiac arrest, and first available setof laboratory investigations was after ROSC. Only significant abnormality noted on initiallaboratory findings was lactic acidosis, which is expected after cardiac arrest. Lactate levelquickly normalized within four hours' time. Laboratory results are shown in Table 1. Pulmonaryembolism (PE) and pneumonia were highly suspected. However, CT angiogram of the chest wasnegative for PE and bronchoscopy was essentially normal. In addition, sepsis workup includingblood cultures, chest x-ray and urinalysis were all found to be negative. Pre-excitationsyndrome was ruled out by electrophysiology, and it was suggested that the shortened PR couldbe due to enhanced atrioventricular (AV) node conduction. A diagnosis remained unclear for thefirst three days of the MICU stay until the patient’s prior history of MG was verified by hisprimary care provider. Treatment with plasmapheresis and methylprednisolone was initiatedresulting in significant improvement of the patient’s condition. Short PR-interval resolvedafter the completion of five sessions of plasmapheresis, and the patient was extubated shortlythereafter. The patient fully recovered and was discharged to regular follow-up and hasremained stable thus far.2020 Andreev et al. Cureus 12(2): e6891. DOI 10.7759/cureus.6891 2 of 5Laboratory Test (Normal Range) ValueHgb (12.9-16.7 g/dL) 10.6 g/dLWBC (4.10-10.10 10x3/uL) 14.90 10x3/uLPLT (153-338 10x3/uL) 318 10x3/uLPT/INR 1.28PTT (23.5-35.5 seconds) 29.5 secGlucose (70-99 mg/dL) 154 mg/dLCreatinine (0.52-1.04 mg/dL) 0.48 mg/dLSodium (133-145 mEq/L) 140 mEq/LPotassium (3.5-5.1 mEq/L) 3.5 mEq/LBicarbonate (22-30 mEq/L) 32 mEq/LCalcium (8.4-10.5 mg/dL) 9.7 mg/dLAnion gap (mEq/L) 27.00 mEq/LAlbumin (3.5-5.0 g/dL) 3.2 g/dLBilirubin total (0.2-1.3 mg/dL) 0.5 mg/dLALT (9-52 U/L) 38 U/LAST (14-36 U/L) 24 U/LMagnesium (1.6-2.3 mg/dL) 1.8 mg/dLLactate (0.70-2.10 mmol/L) 8.90 mmol/LTroponin I (0.000-0.034 ng/mL) 0.031 ng/mLpH, arterial (7.35-7.45) 7.45pCO2, arterial (35.0-45.0 mmHg) 43.3 mmHgpO2, arterial (80.0-110.0 mmHg) 150.0 mmHgHCO3, arterial (22.0-26.0 mmol/L) 29.4 mmol/LO2 saturation, arterial (96.0-97%) 99.0 %TABLE 1: Laboratory values (post cardiac arrest)ALT, alanine aminotransferase; AST, aspartate aminotransferase; Hgb, hemoglobin; INR, international normalized ratio; PLT, platelet;pCO2, partial pressure of carbon dioxide; pO2, partial pressure of oxygen; PT, prothrombin time; PTT, partial thromboplastin time;WBC, white blood cell2020 Andreev et al. Cureus 12(2): e6891. DOI 10.7759/cureus.6891 3 of 5DiscussionIt is well known that symptomatology of MG results from autoimmune destruction of nicotinicacetylcholine receptors located at the neuromuscular junction preventing nerve impulses fromtriggering muscle contractions. Although MG is a neuromuscular autoimmune disorder knownfor predominantly targeting skeletal muscles, there is a growing body of literature pointingtowards cardiac involvement via anti-striational antibodies [3-5]. Acetylcholine receptorantibodies commonly seen in MG are specific to skeletal muscles and do not bind to heartmuscle. However, anti-striational antibodies, including anti-titin, anti-RYR and anti-Kv1.4, dobind to cardiac muscle and have been reported to be present in 47% of the patients with MG [6].Titin is a giant protein found in cardiac and skeletal sarcomere. RyR is a calcium releasechannel found in the sarcoplasmic reticulum with a role in regulating the excitationcontraction coupling through calcium release. Kv 1.4 is a voltage-gated potassium channel.Both skeletal muscle and cardiac muscle are striated, and therefore these antibodies cross-reactbetween skeletal and cardiac muscles, and are thought to trigger an inflammatory reaction andconduction abnormalities.Association between MG and EKG abnormalities has also been investigated in several studies[7-9]. It was noted that ST depression, T-wave inversion, AV and right bundle branch block, aswell as atrial fibrillation, have all been described. Anti-Kv1.4 antibodies have also beenassociated with EKG abnormalities including QT prolongation and T-wave inversion in 60% ofthe patients [10]. In the presence of myocarditis, anti-Kv 1.4 antibodies also have beenassociated with more significant EKG changes such as sick sinus syndrome, complete AV blockand ventricular tachycardia.In a study by Furlund Owe et al., EKG changes in 143 patients with MG were investigated and itwas discovered that there was a shorter PR interval in patients with MG versus control group(156 ms vs 170 ms, p=0.047); however, the PR interval in MG group stayed within limits ofnormal (120-200 ms) [9]. In our patient, initial EKG demonstrated significantly shorted PRinterval (96 ms) without delta wave or pre-excitation syndrome. MC with cardiac arrest andshort PR interval, to our knowledge, was never described in the literature prior to this report.Our patient had a persistently short PR interval for the first days of his MICU stay. However, PRinterval was normalized after the completion of multiple rounds of plasmapheresis (Figure 2). Itis important to note that our patient remained on continuous cardiac monitoring during thelength of his hospital stay and no significant arrhythmia was noted. It is thus possible tohypothesize that the short PR noted in our patient could be a manifestation of MC. Thepresence of a shortened PR interval may be an indicator of life-threatening arrhythmias leadingto cardiac arrest.Association between MG and myocarditis, arrhythmias and heart failure have all also beendescribed in retrospective studies and case reports. Shivamurthy and Parker reported that theyfound 29 case reports and eight retrospective/prospective studies concerning cardiacinvolvement in MG [2]. A total of 48% of the patients were noted with MG and 97% of patientswith MG and thymoma had presence of antibodies against cardiac muscle (anti-titin, anti-ryanodine and anti-Kv 1.4 antibodies) [4]. CT imaging on our patient did not reveal thymoma;however, as mentioned above, the absence of thymoma does not preclude presence of anti-striational antibodies. Testing for anti-striational antibodies is not available in the mostinstitutions in the USA, including ours, and further studies are needed to establish value ofthose antibodies for cardiac screening in MG. The most common cardiac manifestation of MGfound in the literature is myocarditis (37.5% MG patients with anti-striational antibodies) [2].Severe myocarditis typically presents with chest pain, sign of cardiac failure, cardiogenic shock,and diagnosis based on elevation of troponin and plasma brain natriuretic peptide levels,cardiomegaly and decreased left ventricular ejection fraction. In our case, none of thesementioned was present which makes diagnosis of myocarditis unlikely.2020 Andreev et al. Cureus 12(2): e6891. DOI 10.7759/cureus.6891 4 of 5ConclusionsMC presenting as a cardiac arrest without other associated symptoms of MG is rare anddiagnostically challenging, though the incidence of heart disease related to MC remains largelyunknown. Clinicians should be aware of the possibility of cardiac manifestations of MG and beproactive in their approach to treating a cardiac MC since most respond to immunomodulatorytherapy, as did our patient. Most published data consist of case reports or retrospective case-control studies that suggest an association of thymoma and anti-striational antibodies withcardiac involvement in MG. A short PR interval in MC can be an indicator of life-threateningarrhythmias. Prospective studies are needed to further establish recommendations for cardiacscreening in MG.Additional InformationDisclosuresHuman subjects: Consent was obtained by all participants in this study. Conflicts of interest:In compliance with the ICMJE uniform disclosure form, all authors declare the following:Payment/services info: All authors have declared that no financial support was received fromany organization for the submitted work. Financial relationships: All authors have declaredthat they have no financial relationships at present or within the previous three years with anyorganizations that might have an interest in the submitted work. Other relationships: Allauthors have declared that there are no other relationships or activities that could appear tohave influenced the submitted work.References1. Wendell LC, Levine JM: Myasthenic crisis. Neurohospitalist. 2011, 1:16-22.10.1177/19418752103829182. Shivamurthy P, Parker MW: Cardiac manifestations of myasthenia gravis: a systematic review .IJC Metab Endocr. 2014, 5:3-6. 10.1016/j.ijcme.2014.08.0033. Limaye K, Vallurupalli S, Lee RW: Myasthenia of the heart . Am J Med. 2016, 129:19-21.10.1016/j.amjmed.2016.01.0204. Romi F, Skeie GO, Gilhus NE, Aarli JA: Striational antibodies in myasthenia gravis: reactivityand possible clinical significance. Arch Neurol. 2005, 62:442-446. 10.1001/archneur.62.3.4425. Suzuki S, Utsugisawa K, Yoshikawa H, et al.: Autoimmune targets of heart and skeletalmuscles in myasthenia gravis. Arch Neurol. 2009, 66:1334-1338. 10.1001/archneurol.2009.2296. Suzuki S, Utsugisawa K, Nagane Y, Suzuki N: Three types of striational antibodies inmyasthenia gravis. Autoimmune Dis. 2011, 2011:740583. 10.4061/2011/7405837. Kato T, Hirose S, Kumagai S, Ozaki A, Matsumoto S, Inoko M: Electrocardiography as the firststep for the further examination of cardiac Involvement in myasthenia gravis. Biomed Res Int.2016, 2016:8058946. 10.1155/2016/80589468. Calin C, Savu O, Dumitru D, et al.: Cardiac involvement in myasthenia gravis: is there aspecific pattern?. Rom J Intern Med. 2009, 47:179-189.9. Furlund Owe J, Skulstad Davidsen E, Eide GE, Gerdts E, Gilhus NE: Left ventricular long-axisfunction in myasthenia gravis. J Neurol. 2008, 255:1777-1784. 10.1007/s00415-008-0049-x10. Suzuki S, Baba A, Kaida K, et al.: Cardiac involvements in myasthenia gravis associated withanti-Kv1.4 antibodies. Eur J Neurol. 2014, 21:223-230. 10.1111/ene.122342020 Andreev et al. Cureus 12(2): e6891. DOI 10.7759/cureus.6891 5 of 5

A Broken Heart: Cardiac Arrest As the Initial Presentation of Myasthenic Crisis

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A Broken Heart: Cardiac Arrest As the Initial Presentation of Myasthenic Crisis

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