An 18 year old, 27 weeks pregnant, experiences visual disturbances and grand mal seizures. What should you suspect?

In the scenario described, the combination of visual disturbances and grand mal seizures strongly suggests eclampsia. Eclampsia is characterized by the onset of seizures in a pregnant woman who has been diagnosed with preeclampsia or has symptoms consistent with it, including hypertension and signs of end-organ dysfunction. The visual disturbances can indicate cerebral edema or other neurological complications, which are also associated with the eclamptic state.

In this case, the patient is in her third trimester, which is a critical time for the development of preeclampsia and its more severe form, eclampsia. The presence of seizures is a defining feature of eclampsia and differentiates it from other hypertensive disorders of pregnancy. While preeclampsia may present with similar symptoms such as hypertension and visual changes, it does not include seizures until it progresses to eclampsia.

Other options, while related to hypertensive disorders of pregnancy, do not encompass the complete clinical picture observed here. Gestational hypertension might cause elevated blood pressure but typically wouldn't include seizures. Hyperemesis gravidarum is characterized by severe nausea and vomiting, but it does not involve the neurological symptoms that the patient is experiencing. Therefore, the situation clearly aligns