2019 Research Forum

Sean Sayani MD R3, Rachel O’Donnell MD, Daniel Quesada MD, Kieron Barkataki DO, Phillip Aguìñiga-Navarrete RA

A Rare Case of Hiccups as the Only Presenting Symptom of an Underlying Pneumomediastinum

1 PGY-III, Emergency Medicine, Kern Medical, Bakersfield, CA 2 UCLA Health Sciences Clinical Instructor, Emergency Medicine, Kern Medical, Bakersfield, CA 3 Research Coordinator, Emergency Medicine, Kern Medical, Bakersfield, CA

Discussion

Discussion Cont’d.

Case imaging

Abstract

Hiccups (singultus) are often considered a benign condition however, as presented in this case on rare occasions it can be associated with more serious underlying pathologies. Numerous triggers can cause activation of the hiccup reflex pathway. These can range from etiologies that are benign such as gastric distention to more acute scenarios. We illustrate a case of a 36- year-old male who presented with persistent singultus that caused a spontaneous pneumomediastinum (SPM). The underlying mechanism is that of an increase of intrathoracic pressure caused by the singultus leading to alveolar rupture. This in turn may cause SPM. In terms of managing and treating singultus and SPM a thorough workup must be initially done to identify any possible underlying etiologies. Treatment in both cases are multimodal and in rare instances require more invasive procedures Sometimes hiccups do not resolve which such ease as having someone startle you. In select cases, the underlying etiology of the hiccup can be quite startling. Singultus are often a benign condition that spontaneously resolve. 1 In these cases the enticing event is due to an increase in gastric distention, which is the activating factor in the hiccup reflex pathway. 2 Moreover, singultus can be divided into three categories depending on duration: Hiccup bout defined as symptoms lasting up to 48 hours, persistent hiccups which span 48 hours to one month, and intractable hiccups which are greater than one month. 1 As symptoms persist and fall into the latter two categories underlying pathologies should be considered. In this case report we will illustrate a rare occurrence of an a patient with isolated persistent singultus leading to pneumomediastinum Introduction A 36-year-old Hispanic male with a history of EtOH abuse presented to the emergency department secondary to persistent hiccups for 3 days. Patient expresses numerous episodes per minute. Due to the frequency of symptoms expressed an associated shortness of breath. Medical history significant for depression, anxiety, and alcohol abuse. He denied taking any medications. Social history consisted of drinking roughly six 24 ounce beers per day and denied any history of recent retching or vomiting. The patient’s vitals were stable, afebrile and no significant findings observed on exam (other than the patient’s repeated singultus). Labs were only significant for mildly elevated liver enzymes (most likely secondary to alcohol abuse) and an elevated D-dimer of 2267. Patient did not have an elevated white count and troponin was negative. Chest roentgenogram and electrocardiography were performed and both were within normal limits. The patient was initially treated with chlorpromazine and his symptoms resolved. Before the patient was made aware of the lab findings and further workup could be ordered he left the ER absent without leave. He was then subsequently contacted and made aware of the results and he arrived the next day for further evaluations. Singultus had resolved and had not relapsed on the second presentation. CT angiogram of the chest was ordered due to concern of PE. CT was significant for right sided pneumomediastinum extending into the neck. Thoracic surgery was consulted and recommended a barium esophagram, which did not show any esophageal pathology. Patient discharged with follow up CXR in one week which repeatedly did not show any signs of pneumomediastinum. Case Presentation

In the case our patient presented with hiccups with an underlying pneumomediastinum. The etiology of both can be be due to a multitude of triggers. Pneumomediastinum can be separated into two distinct categories: Secondary pneumomediastinum which can be attributed to an underlying pathology. The main etiologies including trauma, gastrointestinal, cardiac, CNS and medications. The second division spontaneous pneumomediastinum is any presentation without unknown direct cause. The underlying mechanism in this scenario is thought to be due to increases in thoracic pressure which lead to alveolar rupture. This rupture leads to the tracking of air through the mediastinum. Most often SPM is observed with episodes of emesis. Other causes include asthma, coughing, physical activity, bowel movements and choking. 3 Moreover, the hiccup pathway that consists of three components can be activated by numerous eliciting factors. The pathway consists of afferent limb, efferent limbs and a central processing area. The initial afferent limb courses with the phrenic and vagus nerves. The afferent limb connects the phrenic/accessory nerves to the diaphragm and the intercostal muscles respectively. The central processing area is where transmitted impulses are processed. This area is thought to be localized to the cervical spine and brainstem. Commonly singultus is usually triggered by gastric distention leading to activation of the afferent limb. 2 However, other initiating etiologies include vagal/phrenic nerve injury, toxins, medications, surgical, infections, psychogenic factors, central nervous system, gastrointestinal, and cardiac pathologies. 3.4 In our specific case it is most likely that the singultus caused the mediastinum. Singultus cause increases in intrathoracic pressure and as stated above can lead to SPM. Odds of this occurring are quite rare nevertheless, as symptoms persist chances increase. A similar documented case was observed in a patient with underlying multiple sclerosis. Numerous identified brain and cervical cord lesions were theorized to cause the patient to have persistent singultus. This led to the eventual development of the spontaneous pneumomediastinum. 5 Addressing the other possibility that the patient had a secondary pneumomediastinum seemed unlikely due to the fact that the patient’s imaging, ekg and labs did not point to a specific source. Although no CNS imaging was done no focal neurological deficits were observed on exam making this etiology unlikely. An extensive workup should be undertaken to determine specific etiologies in non-resolving singultus. Evaluation should include history and physical exam to identify the most likely etiologies. Following this labs and CXR can done initially. Further possible steps include CT imaging and EGD looking for specific pathologies. Gastric pH studies can also be done to rule out possible GERD. When specific underlying causes are theorized (e.g CNS pathology), modalities such as MRI and bronchoscopy can be indicated. 6 Similarly, a thorough history and workup should be done for patients presenting with spontaneous pneumomediastinum. In terms of exam the most common clinic presentation is chest pain in up to 54% of cases. Other symptoms include dyspnea and cough. 7 The present case did not have any of these previously stated factors. Labs are usually non-specific in SPM, but a CBC can aid in localizing underlying infection. An elevated D-dimer is positive in roughly 12% of patients. 8 In terms of imaging XR can miss up to 10–30% of SPM in patients as seen in our case, thus CT is the standard of care for detection. 9 Contrast swallow studies or EGD are not always indicated but should be considered in possible esophageal pathology, trauma, signs of infection, pleural effusion and pneumoperitoneum. 8 A more thorough workup including various labs and imaging should be ordered if specific underlying pathologies/secondary pneumomediastinum are thought to be likely.

References 1. Kolodzik PW & Filers MA. Hiccups (Singultus): Review and approach to management. Ann Emerg Med . 1991; 20(5): 565—573. 2. Becker DE. Nausea, Vomiting, and Hiccups: A Review of Mechanisms and Treatment. Anesth Pro. 2010; 57(4):150— 157. 3. Cymet TC. Retrospective analysis of hiccups in patients at a community hospital from 1995-2000. J Natl Med Assoc . 2002; 94(7): 480—483. 4. Kohse EK, Hollmann MW, Bardenheuer HJ, et al. Chronic Hiccups. Anesth Analg . 2017; 125: 1169—83. 5. Na S-J, Lee SI, Chung T-S, et al. Pneumomediastinum Due to Intractable Hiccup as the Presenting Symptom of Multiple Sclerosis. Yonsei Med J . 2005; 46: 292. 6. Steger M, Schneemann M, Fox M. Systemic review: the pathogenesis and pharmacological treatment of hiccups. Aliment Pharmacol Ther . 2015; 42: 1037—50. 7. Caceres M, Ali SZ, Braud R, et al. Spontaneous Pneumomediastinum: A Comparative Study and Review of the Literature. Ann Throac Surg . 2008; 86(3):962—966. 8. Al-Mufarrej F, Badar J, Gharagozloo F, et al. Spontaneous pneumomediastinum: diagnostic and therapeutic interventions. J Cardiothorac Surg . 2008; 3: 59. 9. Zachariah S, Gharahbaghian L, Perera P, et al. Spontaneous Pneumomediastinum on Bedside Ultrasound: Case Report and Review of the Literature. West J Emerg Med . 2015;16:321—4. Treating isolated singultus can be multimodal. In in the initial phase physical maneuvers can be attempted including nasopharyngeal stimulation (e.g. inhalation of smelling salts), vagal stimulation (e.g. carotid massage) and respiratory maneuvers (e.g. breath holding) to possibly abort the symptoms. If no underlying etiology is identified a trial of PPI might be considered to rule out GERD. Following this, the use of medications to provide symptomatic support should be attempted. Initial pharmacological therapy is usually with chlorpromazine. Other common first line options include metoclopramide and baclofen. Anti-epileptic medications (e.g. phenytoin) are also used as second line agents. Other possible options include carvedilol, amphetamines and amitriptyline. In the last resort, surgical procedures such as phrenic nerve block can be attempted. 6 Spontaneous pneumomediastinum management depends on severity of symptoms. Admission is considered in patients who have worrisome symptoms (e.g. febrile, distress, underlying infection) or when the possibility of secondary pneumomediastinum cannot be ruled out. Management can range from supplemental oxygen to pain control and antibiotics. Complications including pneumothorax associated with the condition might lead to more invasive procedures being required. 9 We have presented a rare case of persistent hiccups causing SPM. The most likely etiology we discern is due to an increase in intrathoracic pressures leading to alveolar rupture. This mechanism is commonly seen with emesis. An extensive history and workup should be done in both cases of non-remitting singultus and pneumomediastinum to help identify and rule out possible etiologies. Treatment for singultus can range from physical maneuvers to medications and in rare instances surgical approaches might be warranted. SPM management similarly is wide ranging from supportive care to invasive procedures.

Image 1. A CT angiogram showing a coronal view of the pneumomediastinum. B. A CT angiogram showing axial view of the pneumomediastinum

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