Posterior reversible encephalopathy syndrome is present in a small minority of patients.This condition features the unique property that the patients cerebral arteries can spontaneously constrict and relax back and forth over a period of time without intervention and without clinical findings. Vasospasm is common post subarachnoid hemorrhage and cerebral aneurysm, but in RCVS only 25% of patients have symptoms post subarachnoid hemorrhage. Causes
The direct cause of the symptoms is believed to be either constriction or dilation of blood vessels in the brain. The pathogenesis is not known definitively, and the condition is likely to result from multiple different disease processes.Up to two-thirds of RCVS cases are associated with an underlying condition or exposure, particularly vasoactive or recreational drug use, complications of pregnancy (eclampsia and pre-eclampsia), and the adjustment period following childbirth called puerperium. Vasoactive drug use is found in about 50% of cases. Implicated drugs include selective serotonin reuptake inhibitors, weight-loss pills such as Hydroxycut, alpha-sympathomimetic decongestants, acute migraine medications, pseudoephedrine, epinephrine, cocaine, and cannabis, among many others. It sometimes follows blood transfusions, certain surgical procedures, swimming, bathing, high altitude experiences, sexual activity, exercise, or coughing. Symptoms can take days or a few months to manifest after a trigger.Following a study and publication in 2007, it is also thought SSRIs, uncontrolled hypertension, endocrine abnormality, and neurosurgical trauma are indicated to potentially cause vasospasm. Diagnosis
The clinician should first rule out conditions with similar symptoms, such as subarachnoid hemorrhage, ischemic stroke, pituitary apoplexy, cerebral artery dissection, meningitis, and  spontaneous cerebrospinal fluid leak.
Such a procedure is unnecessary, given that situs inversus rarely causes any additional symptoms. No treatment, medical or surgical, is prescribed for situs inversus patients, with medical professionals instead treating any other symptoms the patient may have with awareness of the unique anatomy of the patient. Epidemiology
Situs inversus is very rare, affecting 0.01% of the population. This is equivalent to 1 in 10,000 people. History
Dextrocardia (the heart being located on the right side of the thorax) was seen and drawn by Leonardo da Vinci, and then recognised by Marco Aurelio Severino in 1643. Situs inversus was first described more than a century later by Matthew Baillie. Etymology
The term situs inversus is a short form of the Latin phrase situs inversus viscerum, meaning "inverted position of the internal organs". Notable cases
Notable individuals with documented cases of situs inversus include:

Enrique Iglesias, a Spanish singer, songwriter, actor and record producer. Catherine OHara, Canadian-American actress, writer and comedian. Randy Foye, an American basketball player in the NBA. He has suffered no discernible complications, and the condition is not expected to affect his career as a professional athlete, as all his organs are in reverse. Ginggaew Lorsoongnern, a Thai convict executed by firing squad. Her condition was discovered after she was shot in the left side of her chest and survived. After waking up in the morgue she was taken back and executed. Tim Miller, director of the Ashtanga Yoga Center in Carlsbad, California.