Critical Care and Trauma: Case Report
The emergency medical team was called to an unconscious 63-yr-old woman with a history of severe arterial hypertension. Just before losing consciousness she complained of the sudden onset of an excruciating headache. The initial examination revealed a Glasgow coma scale score of 6. Spontaneous eye movement was absent. Gurgling sounds in the throat, opisthotonos, restless movement of the extremities, and abnormal flexion of all extremities were present. Both pupils were in mid-position and reaction to light was delayed. Because of loss of protective reflexes, anesthesia was induced and the trachea was intubated to secure the airway. Cardiovascular examination was normal, with an arterial blood pressure of 160/90 mm Hg in both arms, a normal heart rate, and equilaterally palpable pulses in all extremities and both carotid arteries. Because of the sudden headache shortly before losing consciousness, the comatose state, and the presence of meningism, the patient was suspected to have a subarachnoidal hemorrhage (SAH). On hospital admission, however, the cerebral computed tomography (CCT) and the CT angiography were normal without signs of SAH, early ischemia, or occlusion of intracerebral vessels (Fig. 1, left).
As recommended by the neurologist, the patient was transferred to the intensive care unit and sedation was reduced to enable a second neurological examination later on. Arterial blood pressure was controlled to normal values in the upper range and anticoagulation with acetylsalicylic acid and heparin was started. A CCT, electroencephalogram, and lumbar puncture were planned for the next day. Initial laboratory results showed discrete leukocytosis and increased d-dimers of 9 μg/mL. All other laboratory results and the chest radiograph were normal. An electrocardiogram showed discrete repolarization abnormalities in leads II, III, and aVF. Eight hours later, the patient still did not show adequate reactions to external stimuli. A second chest radiograph revealed a broadened mediastinum, and the diagnosis of a thoracoabdominal aortic dissection (type Stanford A) was verified by a transesophageal echocardiogram and thoracic CT (Fig. 1, right). The dissection involved all supraaortic branches, with proximal dissection of the left common carotid artery but without malperfusion of any supraaortic branch or aortic valve insufficiency. The patient underwent immediate supracoronary aneurysm repair in deep hypothermic cardiac arrest and recovered well without any sequelae.
Aortic dissection is a medical emergency, and prognosis depends mainly on appropriate clinical suspicion. The dissection spreads from diseased segments of the aortic wall in an antegrade or retrograde manner, occludes side branches, and thereby causes complications such as organ malperfusion, cardiac tamponade, or aortic regurgitation. Despite this anatomical relation of aortic dissection to certain malperfusion syndromes, the clinical picture is often confusing, and diagnosis mainly relies on the combination of clinical symptoms and radiological tests. Instantaneous onset of severe chest pain (85%) and back pain (46%) and heart rate deficits (35%) are important clues on physical examination. Cerebrovascular symptoms such as syncope can be a result of pain or of acutely impaired cerebral blood flow caused by carotid artery dissection, thromboembolism, or cardiogenic shock (1). Whereas transient syncope may be observed in up to 20% of patients with aortic dissection, even without additional signs of aortic syndromes, coma is rare, and headache as the initial symptom has been reported only once (2,3). Although headache is an initial manifestation of carotid artery dissection, its onset is usually gradual. Cranial nerve palsies are common, but the median time to their manifestation is four days (4). Therefore, the rapid neurological deterioration in our patient without radiological signs in the initial CCT or additional cardiovascular symptoms is striking. In retrospect, the presence of opisthotonos and neck stiffness were the major confounding signs that delayed appropriate clinical suspicion and treatment. When combined with coma and sudden headache, meningism is considered pathognomonic for SAH, and has not been described during aortic dissection (5). Because SAH was excluded by CCT, the opisthotonos in this unconscious patient was probably a reaction to pain caused by the aortic dissection rather than primary meningism.
This case indicates that aortic dissection, which causes severe pain and possibly transient malperfusion of the carotid arteries, may present with the clinical signs of SAH. Although ultrasonography might have revealed carotid artery dissection, it was not performed in our patient because carotid artery dissection was not considered likely to be the cause of such rapid neurological deterioration given the normal CT angiography. More important, a normal ultrasonography, as well as a normal chest film, does not exclude dissection of the proximal supraaortic branches or the thoracic aorta, but may distract physicians from pursuing further imaging (1). When stroke instead of aortic dissection is thus suspected as a differential diagnosis for SAH, anticoagulation and normal arterial blood pressure values can have fatal consequences for the patient. Because aortic dissection has a mortality rate of 1%–2% per hour (1), one should consider the possibility of aortic dissection until other diagnostic procedures such as an immediate thoracic CT have definitely excluded it.
1. Nienaber CA, Eagle KA. Aortic dissection: new frontiers in diagnosis and management. Part I. From etiology to diagnostic strategies. Circulation 2003;108:628–35.
2. Von Kodolitsch Y, Schwartz AG, Koschyk DH, Nienaber CA. Clinical diagnosis of acute aortic dissection. Z Kardiol 2001;90:339–47.
3. Stollberger C, Finsterer J, Fousek C, et al. Headache as the initial manifestation of acute aortic dissection type A. Cephalalgia 1998;18:583–4.
4. Schievink WI. Spontaneous dissection of the carotid and vertebral arteries. N Engl J Med 2001;344:898–906.
5. Becker KJ. Epidemiology and clinical presentation of aneurysmal subarachnoid hemorrhage. Neurosurg Clin N Am 1998;9:435–44.