Unexplained car crash: what you should consider.

A 30-year-old woman crashed her car into a parked car after leaving work. She was restrained, and the car’s airbag did not deploy. When the paramedics arrived, she was confused and unable to answer questions appropriately. En route to the hospital, she had tonic-clonic seizure that lasted approximately 45 seconds. Upon arrival at the emergency department, she was unresponsive. Her vital signs were as follows: blood pressure, 197/73 mmHg; heart rate, 133 beats per minute; respiratory rate, 18 breaths per minute (unassisted); and oxygen saturation, 96% on a non-rebreather mask. Her blood sugar was measured at 118 mg/dL, and her blood alcohol level was negative. The team intubated her to protect her airway and obtained a head computed tomography (CT) scan. This CT scan showed a small amount of intracranial hemorrhage along the tentorium with no mass effect. Her father arrived and reported that she has a history of depression for which she takes medication, but otherwise is healthy and has had no previous seizures. She was admitted to the ICU with a neurosurgery consult. The neurosurgeons prescribed phenytoin for seizure prophylaxis, and she had a repeat head CT scan that showed no increase in the hemorrhage. She was easily extubated the following morning. The next day, she was feeling well, eating a regular diet, and ambulating independently. No additional injuries were found and she was discharged home with an anti-seizure medication. When she came for her clinic appointment a week later, she stated that she did not know why she crashed her car. She remembered feeling “poorly” at work the day of the crash because of a headache. After further discussion, she recalled having left-sided headaches for several months before her crash, which were increasing in intensity. The physician obtained a magnetic resonance imaging scan that showed a thrombosed left transverse sinus with vasogenic edema. In reviewing her previous head CT scans, the radiologist reported that a superimposed left sinus thrombosis might be obscured by the hemorrhage. The patient was readmitted for anticoagulation and further work-up. Although the reason for a car crash is often known, an unexplained single-car crash should be a red flag to the treatment team. Several underlying causes should be ruled out. Referred to the as “the 6 S’s of single-car crash,” underlying causes may be seizure, sugar, stroke, syncope, suicide, substances, and sleep. Let’s start the discussion with seizures. Certainly, a sudden seizure can cause a patient to crash his or her car. In a survey of emergency physicians, new seizure frequently was rated as the reason for loss of consciousness while driving. One study found that 0.2% of all fatal car crashes were related to drivers having seizures. If, as was reported with this patient, seizures were reported at the scene, it should be considered as a possible cause of the crash. Furthermore, a complete history should be taken to determine the source of the patient’s seizures, especially if the patient had not previously had seizures. Another potential cause of a crash is confusion related to hypoglycemia. A study by Clarke and colleagues in 1999 found that patients with type I diabetes may have poor judgment from low blood glucose, thereby affecting driving or the decision to drive. Furthermore, this study found that diabetics may still drive even if they are aware their blood glucose level is low. While the risk of a diabetic crashing his or her car may not be significantly higher than that of the general population, it clearly is a possible cause of motor vehicle crashes and should be addressed in a patient who possibly has hypoglycemia. Many prehospital providers routinely perform a spot blood glucose check; if it is not done in the field, it certainly should be done in the emergency department in injured patients. Stroke is the third possible cause of unexplained motor vehicle crash. In this category, we can include thrombus, Jean Mullins is a Nursing Student, University of Minnesota.