Syncope in an adult with uncontrolled asthma.

ABSTRACT: Cough syncope occurs primarily in middle-aged male smokers with chronic obstructive pulmonary disease (COPD). It has also been described in children with asthma. I report the case of a 34-year-old nonsmoker who had syncope due to coughing, and who also related a 1-year history of cough with wheezing. Chest examination revealed diffuse wheezing and a prolonged expiratory phase, and pulmonary function testing with a methacholine challenge confirmed hyperreactive airways. Notably, while undergoing spirometric testing he had a recurrent syncopal episode. His syncope resolved with medical therapy for asthma.

COUGH SYNCOPE is well recognized in obese, middle-aged men with a history of smoking and chronic obstructive pulmonary disease (COPD). Syncope due to coughing was initially described more than a century ago and has been labeled by nearly 40 synonyms, including laryngeal vertigo, tussive syncope, posttussive syncope, and cough syndrome. (1) Cases of cough-induced syncope in association with asthma are reported primarily in the pediatric literature. Katz (2) described the disorder in 10 asthmatic children, most of whom had bronchospasm demonstrated by reversibility on pulmonary function testing. Another study reported 12 cases, all involving children with known asthma and typical cough syncope; most of them had complete resolution of syncope after aggressive treatment for asthma. (3) The extent of this disorder among young adult asthmatics is unknown, and it may be underrecognized in this population.

CASE REPORT

A 37-year-old man reported having "passed out" on two occasions. The first episode occurred when he had "laughed uncontrollably" while watching television and had a prolonged episode of coughing. Thereafter, he was observed by his wife to lose consciousness and slump sideways, with his eyes rolling back and his extremities shaking. Upon awakening he felt alert, and his only associated symptom was that he had bitten his tongue. He denied other symptoms consistent with neurologic diseases. A second episode occurred several weeks later while he was watching television, again with the sequence of laughter, coughing, and syncope, but without tongue biting.

Additionally, the patient complained of a productive cough and associated wheezing for the past year. He had seen by other physicians for these respiratory complaints, and the differential diagnosis included gastroesophageal refiux disease and asthma. He had been treated with an albuterol inhaler and a histamine [H.sub.2] receptor blocking medication, without relief of symptoms. On review of systems, he denied fevers, sinus congestion, orthopnea, paroxysmal nocturnal dyspnea, or edema. However, he admitted to coughing when exposed to cold air. He also had a history of hypertension and gastroesophageal reflux disease. His medications were hydrochlorothiazide, atenolol, albuterol inhaler, and famotidine. He was a nonsmoker and had no allergies, and his family and social histories were noncontributory.

On physical examination, the patient appeared comfortable, with normal vital signs. Body mass index was 27.8. General medical examination was unremarkable except for the pulmonary findings, which included diffuse wheezing throughout both lung fields, and a prolonged expiratory phase of respiration. Laboratory studies included a normal complete blood cell count. A 12-lead electrocardiogram showed sinus bradycardia, and a plain film of the chest was unremarkable. Pulmonary function testing showed an [FEV.sub.1] of 2.93 L (68% of predicted), FVC 4.56 L (87% of predicted), normal lung diffusion capacity of carbon monoxide (DLCO), and normal oximetry. Results of bronchial provocative testing were positive, with a 26% decline in [FEV.sub.1] after only one breath of methacholine (25 mg/mL). The patient had an episode of paroxysmal coughing while performing the spirometry test, and he was observed by the technician to have a brief loss of consciousness. The patient claimed this was identical to his previous syncopal episodes. Because of his history of losing consciousness with associated tongue biting, he had awake and sleep electroencephalography with standard activating procedures, which revealed normal background activity and the absence of potentially epileptiform discharges. He also had 24-hour holter monitoring, which showed a basic normal sinus rhythm and no arrhythmias. Findings on transthoracic echocardiogram were also normal.

The patient's constellation of symptoms were considered most consistent with cough-induced syncope due to suboptimally controlled asthma. Consequently, atenolol therapy was discontinued because of the concern that this could be contributing to bronchospasm, and diltiazem therapy was initiated for blood pressure control. He was also given a low daily dose of inhaled fluticasone. On follow-up 2 weeks later, his cough had nearly resolved, he was no longer wheezing, and he denied recurrent syncopal events.

DISCUSSION

Several features of this case are typical of cough syncope. First, patients with this disorder tend to have underlying pulmonary disease, albeit most are overweight, middle-aged, men with COPD. Second, it is not unusual for the loss of consciousness to be associated with arrhythmic jerking of the extremities. (1-3) Third, cough syncope may resemble a seizure disorder, and cough syncope can be differentiated from seizures by taking a careful history. Specifically, patients with cough syncope will almost always give a history of losing consciousness after an episode of paroxysmal coughing. Likewise, the associated clonic movements can be differentiated from those associated with epilepsy, because the patients with cough syncope will have onset of symptoms at an older age and will generally deny an aura, postictal confusion, tongue biting, or loss of bowel or bladder continence. Finally, cough syncope should improve or resolve after the underlying pulmonary disorder has been medically managed. (1,3,4)

The leading explanation for cough syncope is that paroxysms of coughing cause increased intrathoracic pressure, which leads to decreased cardiac venous return, decreased cardiac output, decreased cerebrovascular perfusion, and resulting syncope. (5-7) It has also been observed that patients with chronic obstructive lung disease are at increased risk for cough syncope, since they have prolonged expiratory phases, increased airways resistance, and increased expiratory strength, all of which predispose them to elevated intrathoracic pressures and decreased cardiac output. (4) Additionally, with the generation of lower intrathoracic pressures, patients often report visual changes such as tunnel vision or "seeing stars," whereas with higher pressures outright syncope is observed.

CONCLUSIONS

The patient described herein is unique in that his major presenting symptom of asthma was syncope. The patient is also atypical in that he is a young nonsmoker without emphysema. This case highlights the importance of considering asthma in the differential diagnosis of an adult with syncope. The diagnosis of cough syncope is made by taking a careful history and excluding other causes. The syncope often resolves after optimal management of the underlying pulmonary disease. Since serious injury is a known complication of cough syncope, (8) patients with frequent syncope or symptoms that cannot be medically controlled should be advised not to drive automobiles. Finally, syncope or near syncope can occur during pulmonary function testing. Patients with a history of cough syncope should be closely monitored during maneuvers such as forced vital capacity, which are, known to increase intrathoracic pressure.

References

(1.) Kerr A, Derbes VJ: The syndrome of cough syncope. Ann Intern Med 1953; 39:1240-1253

(2.) Katz RM: Cough syncope in children with asthma. J Pediatr 1970; 77:48-51

(3.) Haslam RH, Freigang B: Cough syncope mimicking epilepsy in asthmatic children. Can J Neurol Sci 1985; 12:45-47

(4.) Bonekat HW, Miles RM, Staats BA: Smoking and cough syncope: follow-up in 45 cases. Int J Addict 1987; 22:413-419

(5.) McCann WS, Bruce RA, Lovejoy FW, et al: Tussive syncope. observations on the disease formerly called laryngeal epilepsy, a report with two cases. Arch Intern Med 1949; 84:845-856

(6.) Sharpey-Schafer EP: The mechanism of syncope after coughing. BMJ 1953; 2:860-863

(7.) Pedersen A, Sandoe E, Hvidberg E, et al: Studies on the mechanism of tussive syncope. Acta Med Scand 1966; 179:653-661

(8.) Adams DK: A note on laryngeal vertigo with record of a case. BMJ 1936; 1:685-687

RELATED ARTICLE: KEY POINTS

* Cough syncope is well recognized in obese, middle-aged men with a history of smoking and chronic obstructive pulmonary disease. The extent of this disorder among young adult asthmatics is unknown.

* Cough syncope may resemble a seizure disorder, and cough syncope can be differentiated from seizures by taking a careful history.

* This case highlights the importance of considering asthma in the differential diagnosis of an adult with syncope.

From the Division of General Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minn.

Reprint requests to Thomas J. Beckman, MD, Mayo Clinic, Division of General Internal Medicine, 200 First St SW, Rochester, MN 55905.