Approximately 80% of SAH cases occur in people aged 40–65 years, with 15% occurring in people aged 20–40 years. Only 5% of SAHs occur in people younger than 20 years. The incidence of SAH is higher in women than men by a rate of 3:2. The risk of SAH is significantly higher in the third semester of pregnancy, and SAH from aneurysmal rupture is a leading cause of maternal morbidity, accounting for between 6%–25% of maternal deaths during pregnancy.7
When an aneurysm ruptures, blood is released under arterial pressure into the subarachnoid space and quickly spreads through the cerebrospinal fluid around the brain and spinal cord. Blood under such pressure may directly damage local brain tissue, and the resultant swelling and irritation lead to increased intracranial pressure.
The signs and symptoms of SAH range from subtle prodromal events, which often are misdiagnosed, to the classic presentation of catastrophic headache. The history and physical examination, especially the neurologic examination, are essential. Sentinel (or warning) leaks that produce minor blood leakage are reported to occur in 30%–50% of aneurysmal SAHs. Sentinel leaks produce sudden focal or generalized head pain that may be severe. Sentinel headaches precede aneurysm rupture by a few hours to a few months, with a reported mean of two weeks prior to discovery of the SAH. In addition to headaches, sentinel leaks may produce nausea, vomiting, photophobia, malaise or, less commonly, neck pain. These symptoms may be ignored by the care provider unless a high index of suspicion is maintained for SAH.
A patient complaining of “the worst headache of my life” should be presumed to be having an SAH until proven otherwise. These words are used as the textbook definition of SAH and bear great weight in establishing a diagnosis and treatment plan.
Symptoms of meningeal irritation (neck or back pain increasing with movement) are also very common, but can present long after the headache. Seizures during the acute phase of SAH occur in 10%–25% of patients. Blood pressure elevation is observed in about 50% of the patients; myocardial ischemia is present in about 20% of SAH cases. The regular expected findings of an intracranial event, one-sided weakness, trouble speaking and/or swallowing, and facial droop may also be seen.
Treatment, as always, centers around the ABCs. All patients should be monitored for their ability to maintain their own airway, as this ability can be suddenly lost as the hemorrhage progresses. BLS care is traditional, and again involves contacting medical control for authorization to bypass a local hospital for a facility that is prepared for urgent advanced radiological and neurosurgical procedures. It should be stressed for ALS providers that intravenous beta-blockers, which have a relatively short half-life, can be titrated easily, do not increase intracranial pressure (ICP) and are preferred over nitrates, which elevate ICP. Medical control should be fully advised of the patient’s status so appropriate measures can be taken. Patients with signs of increased ICP or herniation should be intubated and hyperventilated. Excessive hyperventilation is to be avoided, as it may increase vasospasm and cerebral ischemia.7
Ectopic pregnancy is any pregnancy in which the fertilized egg implants outside the intrauterine cavity. More than 95% of ectopic pregnancies occur in the fallopian tubes. No site besides the uterus is suited to accommodate placental attachment or a growing embryo. As the embryo outgrows its space in the small fallopian tubes, the chance for rupture of the tube and hemorrhage increases. Ectopic pregnancy occurs in 19.7 cases per 1,000 pregnancies in North America and is the leading cause of maternal mortality in the first trimester, accounting for 10%–15% of all maternal deaths. Ruptured ectopic pregnancy is a true emergency.
Several factors increase the risk of ectopic pregnancy, but share a common mechanism: interference with fallopian tube function. These include pelvic inflammatory disease (PID), which is most often associated with infection from chlamydia or gonorrhea. These can be silent infections that a woman does not know she has. These infections can scar the fallopian tubes and prevent easy passage of the egg into the uterus. A previous ectopic pregnancy is also a significant risk factor, as is endometriosis and a history of cigarette smoking.