Preeclampsia/Eclampsia

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• Abnormal Placentation and Endothelial Dysfunction: The core mechanical breakdown of preeclampsia/eclampsia is abnormal remodeling of the maternal uterine spiral arteries by cytotrophoblasts. This failure of high-flow vascular adaptation leads to chronic placental hypoperfusion, ischemic injury, and the release of antiangiogenic factors into the maternal bloodstream.
• Widespread Endothelial Vasospasm: These circulating factors trigger systemic endothelial cell activation and direct vasospasm, altering the delicate balance of vasoactive mediators (resulting in an excess of thromboxane over prostacyclin). This drives multi-organ microvascular dysfunction, plasma volume contraction (via capillary leak), and intravascular coagulation.
• Cerebral Autoregulation Failure: Unlike patients with chronic hypertension, the young and previously healthy obstetric population has no chronic shifting of the cerebral autoregulation curve. Consequently, when systemic blood pressures spike acutely above the cerebral perfusion limits, microvascular shear forces cause capillary leakage, vasogenic edema, and petechial hemorrhages in the cortex and subcortical white matter.
• Lowered Seizure Threshold: This mechanical stretching, localized ischemia, and posterior-dominant edema (often manifesting radiographically as Posterior Reversible Encephalopathy Syndrome [PRES]) disrupt normal neuronal membranes. The resulting synchronous, unregulated cortical firing produces the generalized tonic-clonic activity defined as eclampsia.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

Maternal stabilization, aggressive seizure prophylaxis, and controlled blood pressure reduction must occur simultaneously.

• Step 1: Relieve Aortocaval Compression: For any patient at \(\ge\)20 weeks’ gestation, place the patient in a left lateral tilt position (15 to 30 degrees) or perform continuous manual leftward uterine displacement to decompress the inferior vena cava and restore cardiac preload.
• Step 2: Administer First-Line Seizure Prophylaxis (Magnesium Sulfate):
• First-Line Regimen: Administer Magnesium Sulfate 4 to 6 g IV bolus diluted in a 100-mL aliquot and infused over 15 to 30 minutes. Follow immediately with a continuous maintenance infusion of 2 g/hour IV.
• Alternative Weight-Based Regimen (For patients <60 kg): Administer 55 mg/kg IV loading dose (e.g., 4 g IV) over 20 to 30 minutes, followed by a continuous infusion of 15 mg/kg/hour (e.g., 1 g/hour) for 24 hours.
• No IV Access Option: Administer Magnesium Sulfate 10 g IM total as two separate 5 g IM injections (one in each gluteal region), followed by 5 g IM every 4 hours.
• Renal Adjustment: Magnesium is renally excreted; in patients with progressive renal insufficiency, reduce the loading dose to 2 g IV bolus and obtain serial serum magnesium levels.
• Step 3: Initiate Rapid, Expeditious Antihypertensive Therapy:
• First-Line Agents (To be administered within 30 to 60 minutes of confirmed severe hypertension [\(\ge\)160/110 mm Hg]):
• Labetalol: Give 20 mg IV slow push. If blood pressure remains \(\ge\)160/110 mm Hg after 10 minutes, escalate to 40 mg IV, then 80 mg IV every 10 minutes (maximum single dose 80 mg; maximum cumulative dose 220 to 300 mg).
• Hydralazine: Give 5 to 10 mg IV push. Repeat at 5 to 10 mg IV in 20 to 40 minutes if needed (maximum total dose 20 mg). IM Option: If no IV access is available, give 5 to 10 mg IM every 20 to 40 minutes (maximum total dose 30 mg).
• Nifedipine: If IV access is delayed, administer 10 mg PO (immediate-release). Repeat at 20 mg PO every 20 minutes if blood pressure remains \(\ge\)160/110 mm Hg.
• Antihypertensive Target: Reduce blood pressure to a safe maternal threshold of 140 to 150 mm Hg systolic and 90 to 100 mm Hg diastolic to prevent maternal stroke while strictly preserving critical placental perfusion.
• Step 4: Manage Refractory Seizures:
• If seizures recur despite magnesium loading, administer a 2 to 4 g IV bolus of Magnesium Sulfate over 10 minutes.
• If seizures are completely refractory to magnesium, initiate second-line anti-seizure medications:
• Lorazepam: 2 to 4 mg IV (may repeat once in 10 to 15 minutes).
• Fosphenytoin/Phenytoin: 15 to 20 mg/kg IV (run phenytoin no faster than 50 mg/min; may repeat at 10 mg/kg after 20 minutes).
• Levetiracetam: 20 to 60 mg/kg IV.
• Step 5: Control Sympathetic Flash Pulmonary Edema (SCAPE):
• For patients who develop acute pulmonary edema, place on non-invasive positive pressure ventilation (BiPAP/CPAP) and initiate high-dose IV Nitroglycerin (500 to 1,000 mcg bolus or titration). Avoid diuretics unless severe, persistent volume overload is documented.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Top 4 Can't-Miss Differential Diagnoses:

1. Amniotic Fluid Embolism (AFE): Presents during or immediately after labor with sudden maternal cardiovascular collapse, hypovolemia, severe respiratory distress, hypoxia, and rapid consumptive coagulopathy/DIC. Differentiate by the sudden onset of profound hypoxia and anaphylactoid shock.
2. Cerebral Venous Sinus Thrombosis (CVST): Presents with progressive, severe headache, focal neurological signs, and seizures in the postpartum window. It is highly associated with pregnancy-related hypercoagulability and is often misdiagnosed as eclampsia; differentiate via MRV/CTV.
3. Acute Fatty Liver of Pregnancy (AFLP): Presents in the late third trimester with severe RUQ pain, nausea, vomiting, jaundice, profound hypoglycemia, and rapid liver failure. Strongly mimics HELLP syndrome; differentiate utilizing the Swansea Criteria (which highlight key features of liver failure, severe hypoglycemia, and hyperammonemia).
4. Epilepsy / Status Epilepticus: Characterized by generalized seizures but is distinguished from eclampsia by a prior documented history, a lack of postpartum preeclamptic features, and normal blood pressures.

Prioritized Emergency Workup Strategy:

• Complete Blood Count (CBC) with Platelets: To screen for thrombocytopenia (\(<100,000/\mu\text{L}\)) and microangiopathic hemolytic anemia.
• Renal Function Panel & Creatinine: Creatinine level \(>1.1\text{ mg/dL}\) or doubling of baseline represents progressive renal insufficiency.
• Liver Function Tests (ALT, AST, LDH, Bilirubin): Transaminitis with levels elevated to twice normal (or AST/ALT \(>70\text{ U/L}\)) and elevated LDH are indicative of HELLP syndrome.
• Coagulation Profile (PT, PTT, Fibrinogen): Critical to evaluate for early disseminated intravascular coagulation (DIC), which can complicate severe preeclampsia/HELLP.
• Urinary Evaluation: Perform a urinalysis to check for proteinuria (spot protein-to-creatinine ratio \(\ge\)0.3, or a dipstick reading \(\ge\)2+). Note: Urine dipstick has poor sensitivity for ruling out preeclampsia and should only be relied upon if quantitative testing is unavailable.
• Serum Uric Acid: Frequently requested by obstetrics as a marker of severity.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• Standard 12-Lead ECG Checklist:
• Postpartum and late-pregnancy patients are at exceptionally high risk for acute coronary syndromes, particularly Spontaneous Coronary Artery Dissection (SCAD). Use the ECG to exclude ST-segment elevations or depressions representing acute myocardial ischemia.
• Ensure normal physiologic shifts of pregnancy are recognized: leftward deviation of the mean QRS axis (averaging 15 degrees due to diaphragmatic elevation), transient PR interval shortening, and isolated Q waves or T-wave flattening in the inferior leads (II, III, aVF).
• Point-of-Care Ultrasound (POCUS) Checklist:
• Cardiac/Hemodynamic View: Perform focused cardiac ultrasound to assess left ventricular function. Rule out right ventricular strain (pulmonary embolism) and global left ventricular systolic dysfunction consistent with Peripartum Cardiomyopathy (PPCM).
• Lung Ultrasound Sweep: Scan the chest for bilateral B-lines (comet-tail artifacts) and pleural effusions, which are highly sensitive for detecting early, subclinical cardiogenic or non-cardiogenic pulmonary edema.
• Fetal Evaluation: Perform a transabdominal scan to document fetal heart rate (normal 120–160 bpm; bradycardia \(<110\text{ bpm}\) is a sign of distress), confirm fetal lie/presentation, and rapidly estimate gestational age if unknown.
• Neuroimaging (CT / MRI of the Head):
• Indication Warning: Routine imaging is not indicated for standard preeclampsia/eclampsia.
• Mandatory Head CT/MRI Indications: Perform imaging immediately if the patient exhibits persistent focal neurological deficits, prolonged loss of consciousness, persistent encephalopathy, or if seizures are refractory to standard therapeutic loading of magnesium sulfate.
• Expected Findings: Classic CT/MRI findings of eclampsia include patchy petechial hemorrhages, cortical microinfarcts, and bilateral parieto-occipital hypodensities consistent with vasogenic cerebral edema (PRES). Use abdominal lead shielding for CT scans.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

1. ACOG Diagnostic Criteria for Preeclampsia

The diagnosis is established based on new-onset hypertension after 20 weeks’ gestation (defined as systolic BP \(\ge\)140 mm Hg or diastolic BP \(\ge\)90 mm Hg measured on two occasions at least 4 hours apart) PLUS either proteinuria (\(\ge\)300 mg per 24-hour collection, or spot protein:creatinine ratio \(\ge\)0.3).

In the absence of proteinuria, preeclampsia is diagnosed if the patient has new-onset hypertension combined with any of the following Severe Features:

| System / Feature | Diagnostic Threshold Criteria |
| :--- | :--- |
| **Severe Hypertension** | Systolic BP \\(\ge\\)160 mm Hg or diastolic BP \\(\ge\\)110 mm Hg on two occasions at least 4 hours apart while on bed rest. |
| **Thrombocytopenia** | Platelet count \\(<100,000/\mu\text{L}\\). |
| **Impaired Liver Function** | Liver transaminases (AST/ALT) elevated to twice normal, or persistent right upper quadrant/epigastric pain unresponsive to medication. |
| **Progressive Renal Insufficiency** | Serum creatinine level \\(>1.1\text{ mg/dL}\\) or doubling of baseline in the absence of other renal disease. |
| **Pulmonary Edema** | Clinical or radiographic evidence of pulmonary fluid overload. |
| **Cerebral / Visual Symptoms** | New-onset headache (persistent, frontal, occipital, or thunderclap) unresponsive to acetaminophen, photophobia, blurred vision, or diplopia. |

2. Clinical Disposition Guidelines

• Admission Mandate: All patients diagnosed with preeclampsia with severe features or eclampsia must be admitted to the hospital. Discharge from the ED is strictly contraindicated. Patients must be transferred directly to a Labor & Delivery unit capable of continuous maternal and fetal cardiotocographic monitoring and advanced neonatal resuscitation.
• Outpatient Expectant Management Criteria: Outpatient expectant management is strictly reserved for patients with preeclampsia without severe features who are remote from term (\(<37\text{ }0/7\) weeks’ gestation) and meet all of the following:

    1.  Reassuring fetal surveillance (normal non-stress test, normal ultrasound, and biophysical profile).
    2.  No preterm labor or premature rupture of membranes.
    3.  No active vaginal bleeding.
    4.  Ability to perform close, daily blood pressure monitoring and weekly laboratory evaluations.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

Deadly Cognitive Traps & Trainee Errors:

• The Proteinuria Diagnostic Trap: Failing to diagnose preeclampsia because there is no protein in the urine. Up to 10% of preeclamptic patients and those with HELLP syndrome have no proteinuria on presentation; the diagnosis is established based on severe features and end-organ dysfunction.
• The Postpartum Blind Spot: Reassuring a postpartum patient presenting with a severe headache and elevated blood pressure because "she has already delivered". Preeclampsia and eclampsia can manifest up to 6 to 12 weeks postpartum; more than half of late-onset eclampsia cases occur in patients with no prior history of prenatal preeclampsia.
• The Gastroenteritis Premature Closure in HELLP: Discharging a pregnant patient over 20 weeks with epigastric or right upper quadrant pain under the assumption of "gastroenteritis" or "acid reflux". HELLP syndrome classically presents as RUQ or epigastric pain and may completely lack hypertension or proteinuria initially.
• Aggressive Fluid Resuscitation Disaster: Administering large crystalloid fluid boluses to a preeclamptic patient in the ED. Due to systemic endothelial leak and capillary injury, these patients are at an extreme risk for rapid progression to fatal pulmonary edema. Uteroplacental fluid administration must be strictly restricted to a total of 80 mL/hour or 1 mL/kg/hour unless active hemorrhage is present.
• Refractory Seizure Benzodiazepine Over-reliance: Attempting to treat eclamptic seizures primarily with repeated doses of lorazepam or diazepam. Magnesium sulfate is the gold-standard anticonvulsant of choice; it halves the risk of recurrent seizures compared to benzodiazepines and phenytoin while preserving essential uterine blood flow.

Board-Mandated Critical Actions:

• Initiate Magnesium Sulfate seizure prophylaxis immediately in any pregnant or postpartum patient presenting with preeclampsia with severe features.
• Initiate immediate, titratable IV antihypertensives (Labetalol or Hydralazine) for any blood pressure confirmed at \(\ge\)160/110 mm Hg to prevent maternal stroke.
• Strictly restrict maternal fluid intake to 80 mL/hour in preeclamptic patients to protect against acute pulmonary edema.
• Never perform a digital or speculum vaginal examination in any patient beyond 20 weeks' gestation presenting with vaginal bleeding until placenta previa has been formally excluded by ultrasound.

7. MCQ MASTERCLASS (Written Exam Tips)

• High-Yield "Buzzwords":
• "24-year-old primigravida at 32 weeks presents with severe headache, blurry vision, RUQ tenderness, and AST of 120 U/L" \(\rightarrow\) Preeclampsia with Severe Features (HELLP Variant).
• "Postpartum female presents 10 days after delivery with new-onset generalized seizures and elevated blood pressure" \(\rightarrow\) Late-Onset Postpartum Eclampsia.
• "A preeclamptic patient receiving an intravenous infusion of magnesium sulfate develops a loss of patellar reflexes and a respiratory rate of 8 breaths/min" \(\rightarrow\) Magnesium Toxicity. The next step is to immediately stop the infusion and administer Calcium Gluconate 1 g IV slowly.
• Distractor Buster:
• The "Next Best Step in Active Seizure" Distractor: A patient at 28 weeks’ gestation is actively seizing in the ED. Distractors will include administering IV fosphenytoin, IV lorazepam, or immediate endotracheal intubation. Choose "Administer Magnesium Sulfate 4 to 6 grams IV slowly over 15 to 20 minutes". Magnesium is the first-line anticonvulsant; benzodiazepines are only second-line for magnesium-refractory eclampsia.
• The "Post-delivery Eclampsia Headache" Distractor: A patient presents on postpartum day 5 with the "worst headache of her life." Her blood pressure is 158/92 mm Hg. Distractors will suggest discharging her with outpatient migraine therapies. Choose "Perform non-contrast Head CT with abdominal shielding," as postpartum patients are at high risk for intracranial hemorrhage or CVST, and new-onset, atypical headaches are red flags for severe eclamptic pathology.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

Mandatory OSCE Communication Actions:

• Specialist Mobilization Declaration: "I am immediately contacting our senior Obstetrics, Anesthesiology, and Neonatal Intensive Care teams to activate our high-risk obstetric protocol and prepare for definitive delivery, which is the only resolution for preeclampsia".
• Declare Safety Measures: "I am immediately stating for the record that because this patient is in her third trimester with suspected severe preeclampsia, she is at an extreme risk for stroke and eclamptic seizures. I will establish a quiet, low-stimulus environment, place her on continuous cardiotocographic fetal monitoring, and strictly avoid performing any digital vaginal exams until a transabdominal ultrasound has localized the placenta".

High-Yield Phrasing to Use under High-Stress Testing:

• Maternal Resuscitation & Leftward Displacement Command: "resuscitating the mother is our absolute first priority and represents the single most effective way to optimize fetal perfusion. I will instruct a team member to perform continuous manual leftward displacement of the uterus to decompress her inferior vena cava. I am securing her airway, placing her on high-flow oxygen, and establishing two large-bore peripheral IV lines above the diaphragm".
• Anti-Seizure Command: "Because the progression of preeclampsia to eclampsia is highly unpredictable and can occur rapidly, I am immediately initiating a loading dose of Magnesium Sulfate 4 to 6 grams IV infused over 20 minutes, followed by a continuous maintenance infusion of 2 grams per hour to terminate and prevent further seizures. If she is under 60 kg, I will initiate weight-based dosing at 55 mg/kg IV".
• Stroke Prevention Antihypertensive Push: "Her blood pressure is confirmed at 172/112 mm Hg. This is an obstetric hypertensive emergency that presents an immediate maternal stroke risk due to un-reset cerebral autoregulatory thresholds. I am immediately administering Labetalol 20 mg IV slow push, with the goal of safely reducing her blood pressure to a target of 140 to 150 mm Hg systolic and 90 to 100 mm Hg diastolic. If she has a history of asthma or bradycardia, I will instead utilize Hydralazine 5 mg IV push or oral Nifedipine 10 mg".
• Pulmonary Edema Avoidance Statement: "To protect this patient from endothelial capillary leak and rapid progression to acute pulmonary edema, I am placing her on a strict fluid restriction of 80 mL/hour of isotonic crystalloids, and I will monitor her urine output continuously, keeping a strict target of greater than 25 mL/hour".
• Magnesium Toxicity Check & Antidote: "I am instructing the nursing staff to perform serial clinical examinations every 15 minutes, looking specifically for loss of deep tendon patellar reflexes or a decrease in her respiratory rate, which are signs of magnesium toxicity. If signs of toxicity manifest, I will immediately halt the magnesium infusion and administer Calcium Gluconate 1 gram IV slowly over 5 to 10 minutes".