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Introduction. Scorpion stings are a significant health problem as they can cause various clinical symptoms, including neuromuscular and cardiovascular ones. Case Report.A female in her sixth decade presented with a clinical diagnosis of grade III scorpion sting intoxication, manifesting sustained precordial pain with left-bundle branch block without elevation of cardiac enzymes, despite the administration of an antidote and supportive management. Conclusions. Scorpion stings can present with atypical cardiovascular manifestations. This report highlights the need for awareness and further research on the cardiovascular effects of scorpion venom to improve patient outcomes.
Introducción. Las picaduras de alacrán son un problema importante de salud debido a que pueden causar una amplia gama de síntomas clínicos, incluidos los de tipo neuromuscular y cardiovascular. Caso clínico. Mujer de 58 años con diagnóstico clínico de intoxicación por picadura de alacrán grado III, que presentó dolor precordial sostenido con bloqueo de rama izquierda sin elevación de enzimas cardíacas a pesar de la aplicación de antídoto y el manejo de soporte. Conclusiones. Las picaduras de alacrán pueden presentar manifestaciones cardiovasculares atípicas. Este caso resalta la importancia de llevar a cabo mayor investigación acerca de los efectos cardiovasculares del veneno de alacrán para mejorar los resultados en los pacientes.
Scorpion stings are a public health issue in tropical and subtropical regions where these arachnids are endemic. Globally, an estimated 1.2 million scorpion stings occur annually, resulting in over 3,250 deaths.1 In Mexico, the numbers are exceptionally high, specifically in Jalisco, Guerrero, Guanajuato, Michoacán, and Morelos, with 194,482 cases reported in 2023 and 287,581 cases recorded up to week 46 of 2024.1-3
Scorpion venom contains a complex mixture of neurotoxins, cardiotoxins, and other bioactive compounds that can cause local and systemic clinical manifestations.4 Systemic toxicity includes neuromuscular symptoms such as paresthesia and muscle spasms, as well as cardiovascular manifestations like hypertension, tachycardia, and, in severe cases, myocardial dysfunction and shock.5,6
Left-bundle branch block (LBBB) associated with scorpion envenomation is a rare and underdocumented cardiovascular manifestation. It reflects a disruption in the heart’s electrical conduction system, which may suggest myocardial ischemia or other underlying cardiac conditions.7,8 However, the absence of elevated cardiac enzymes, such as troponin, raises questions about the underlying pathophysiological mechanisms involved.
Recent studies indicate that venom neurotoxins can alter autonomic homeostasis, inducing transient dysfunctions in the cardiovascular system without detectable myocardial damage.9 Furthermore, factors such as post-traumatic anxiety and somatosensory amplification could contribute to the persistent perception of symptoms such as precordial pain.10,11
This is the case of a 58-year-old female patient who experienced precordial pain following a scorpion sting.
Medical History
The patient had no chronic degenerative diseases, no history of substance abuse, and no exposure to biomass. She reported an allergy to penicillin and a surgical history of two cesarean sections, and an oophorectomy.
Current Condition
The patient described the onset of precordial pain with an intensity of 6/10, exacerbated by movement. This condition began after a scorpion sting on July 30th, 2023, on the third finger of her left hand. She mentioned discovering the presence of the scorpion in her clothing. She attributed the pain to the sting, which had persisted constantly since then. Initially treated at a Red Cross Unit, her condition was classified as Grade I scorpion envenomation (pain and paresthesia). During her stay, the clinical condition progressed to Grade III envenomation (precordial pain) within 30 minutes of medical attention. Management with parenteral solutions was initiated: 0.9% saline solution at 70 ml/hour, polyvalent anti-scorpion antivenom (4 doses), and dual analgesia (paracetamol 1 gram IV [intravenous] single dose + ketorolac 30 mg IV single dose).
Electrocardiographic findings later showed a new-onset LBBB. Supplemental oxygen was administered to achieve SpO2 > 94%, cardiac monitoring was initiated, and her transfer to her primary care facility was arranged. The patient reported that the pain radiated from the sting site to her shoulder and left thoracic area, with an initial intensity of 2/10, increasing to 5/10. Currently, she denies angina-equivalent symptoms and has no signs of vasovagal episodes. She was referred to a secondary-level care unit for evaluation and follow-up of precordial pain, where she was admitted on July 30th, 2023, at 13:08.
Admission
The patient was admitted with vital signs of heart rate (HR) 71 beats per minute (bpm), respiratory rate (RR) 18 breaths/min, blood pressure (BP) 110/70 millimeters of mercury (mmHg), temperature of 36.3°C, and oxygen saturation (SpO2) of 99%. She was awake, alert, and oriented to time, place, person, and situation. Pupils were isochoric and normoreactive with a diameter of 2 mm. Facial symmetry was preserved, and speech was normal.
The cardiorespiratory examination showed well-ventilated lung fields without crackles or wheezes. The precordium was rhythmic, without additional sounds, and tender to palpation between the third and fifth intercostal spaces. The abdomen was distended due to adipose tissue, with normal peristalsis frequency and tone. It was soft and depressible, with no organomegaly or peritoneal irritation. The extremities were intact, without edema, and with normal muscle tone and strength.
The patient, in her sixth decade of life, was admitted to our ward for follow-up and management of precordial pain. Laboratory tests showed the same electrocardiographic (ECG) pattern as the EKG taken at the Red Cross. Cardiac biomarkers were requested, but the trace did not meet Sgarbossa criteria. However, continuous hemodynamic monitoring and telemetry were maintained. Due to the absence of a typical pain pattern suggestive of cardiac characteristics, aspirin (ASA) and analgesia were prescribed, with a dose of 150 milligrams (mg) taken orally (PO).
During her hospitalization, the patient did not exhibit signs of low-cardiac output; however, localized pain in the left upper extremity persisted. Two enzymatic determinations were negative, and she was discharged on August 1st, 2023, at 07:14, with warning signs provided. She was advised to follow up with her family physician at her primary care unit. She was prescribed atorvastatin 20 mg every 24 hours, metoclopramide 10 mg every 8 hours if needed for nausea or vomiting, paracetamol 1 gram every 8 hours for 3 days, and an open emergency room appointment.
Laboratory Results
Additional Tests
Scorpion stings can present a broad spectrum of clinical manifestations, and this case highlights the importance of considering differential diagnoses when precordial pain and LBBB occur without cardiac enzyme elevation.
Although the exact mechanism behind this presentation is not fully understood, healthcare professionals must maintain close monitoring and a multidisciplinary approach to managing these cases. Continuous cardiac monitoring, appropriate analgesia administration, and consideration of psychological factors such as somatization are essential components of therapeutic management.10
This case report emphasizes the need for further studies and clinical reports to improve understanding of interactions between scorpion venom and the cardiovascular system. Ongoing medical education and awareness of these atypical presentations can help improve clinical outcomes and provide more effective care for patients affected by scorpion stings.
We want to express our sincere gratitude to the Emergency Department teams from Cruz Roja Mexicana, Delegación León, and Hospital General Regional No. 58. Their dedication, expertise, and commitment were fundamental in managing and successfully resolving this case.
The authors have no conflicts of interest regarding this manuscript.
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