A nurse is assessing a client at 34 weeks gestation who reports a severe headache, visual disturbances, and has a blood pressure of 158/104 mmHg. What condition is MOST concerning?

PREECLAMPSIA is a serious obstetric emergency defined as: new onset hypertension (BP ≥140/90 mmHg on two separate occasions 4 hours apart) after 20 weeks gestation PLUS one of: proteinuria; other severe features. SEVERE FEATURES (indicating severe preeclampsia): BP ≥160/110 mmHg; severe headache unrelieved by medication; visual disturbances (blurred vision, scotoma, photophobia); right upper quadrant or epigastric pain (liver distension); thrombocytopenia (platelets <100,000); renal insufficiency (creatinine >1.1); pulmonary edema. The client in this question has MULTIPLE severe features: BP 158/104 (approaching severe threshold); severe headache; visual disturbances — this is URGENT. PROGRESSION RISKS: ECLAMPSIA — grand mal seizures in a pregnant or postpartum woman without other cause; highly dangerous for mother and fetus; HELLP SYNDROME — Hemolysis, Elevated Liver enzymes, Low Platelets — can occur with or without hypertension; STROKE — from sudden severe hypertension; PLACENTAL ABRUPTION — increased risk. NURSING PRIORITY: Notify RN/provider IMMEDIATELY; this is not a 'watch and wait' situation; place on continuous fetal monitoring; prepare for possible magnesium sulfate (seizure prophylaxis) and antihypertensive treatment; prepare for possible delivery. MAGNESIUM SULFATE: Drug of choice for seizure prevention in preeclampsia; loading dose then continuous infusion; monitor for toxicity (loss of patellar reflex, respiratory depression, oliguria); antidote is calcium gluconate.