How do I differentiate between pregnancy-induced hypertension and eclampsia in a pregnant adult woman in her second or third trimester with no other specified medical history?

Differentiating Pregnancy-Induced Hypertension and Eclampsia

Pregnancy-induced (gestational) hypertension is defined as new-onset hypertension (BP ≥140/90 mmHg) arising after 20 weeks' gestation without proteinuria or organ dysfunction, while eclampsia is the occurrence of new-onset generalized tonic-clonic seizures in a woman with preeclampsia. 1, 2, 3

Key Diagnostic Framework

The critical distinction lies in understanding the progression spectrum: gestational hypertension → preeclampsia → eclampsia. 1, 2

Gestational Hypertension (Pregnancy-Induced Hypertension)

Blood Pressure Criteria:

• Systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg developing after 20 weeks' gestation 1, 2
• Must have documented normal BP before 20 weeks or in early pregnancy 1

Defining Characteristics:

• Isolated hypertension only - no proteinuria, no maternal organ dysfunction, no fetal complications 2, 4
• No evidence of end-organ damage on laboratory testing 5
• Resolves within 12 weeks postpartum (if it persists beyond 3 months, the patient likely has underlying chronic hypertension) 1

Preeclampsia

Diagnostic Requirements:

• Gestational hypertension (BP ≥140/90 mmHg after 20 weeks) PLUS at least one of the following: 2, 6
  • Proteinuria (≥0.3 g/24 hours or protein/creatinine ratio >0.3) 7, 6
  • Renal insufficiency (creatinine >1.1 mg/dL or doubling of baseline) 7
  • Liver involvement (transaminases ≥2× upper limit of normal) 7, 6
  • Thrombocytopenia (platelets <100,000/µL) 7, 6
  • Neurological complications (new-onset headache unresponsive to medication, visual disturbances, scotomata) 7, 6
  • Pulmonary edema 6
  • Uteroplacental dysfunction (fetal growth restriction) 2

Severe Features (any one of the following):

• Severe hypertension: BP ≥160/110 mmHg 2
• Severe persistent right upper quadrant or epigastric pain (indicates liver capsule distension from hepatic edema/hemorrhage) 7, 6
• Serum creatinine >1.1 mg/dL or doubling of baseline 7
• Platelet count <100,000/µL 7
• Liver transaminases ≥2× upper limit normal 7
• New cerebral or visual symptoms unresponsive to treatment 7

Eclampsia

Defining Feature:

• New-onset generalized tonic-clonic seizures in a woman with preeclampsia 3
• Seizures cannot be attributed to other causes 3

Timing of Occurrence:

• Can occur antepartum (after 20 weeks' gestation), intrapartum, or postpartum 3
• Rarely occurs before 20 weeks (if so, consider gestational trophoblastic disease) 3

Practical Clinical Algorithm

Step 1: Confirm Timing and Blood Pressure

• Is BP ≥140/90 mmHg? 1, 2
• Did hypertension develop after 20 weeks' gestation? 1, 2
• If yes to both → proceed to Step 2
• If hypertension present before 20 weeks → chronic hypertension, not gestational 1

Step 2: Assess for Organ Dysfunction

Obtain immediate laboratory evaluation: 6

• Complete blood count with platelets
• Liver enzymes (AST, ALT, LDH)
• Serum creatinine and uric acid
• Urinalysis with protein quantification (24-hour urine or protein/creatinine ratio)

Step 3: Classify Based on Findings

• Hypertension alone, all labs normal → Gestational hypertension 2, 4
• Hypertension + any organ dysfunction or proteinuria → Preeclampsia 2, 6
• Preeclampsia + seizures → Eclampsia 3

Step 4: Identify Severe Features

If preeclampsia is diagnosed, assess for any severe features (BP ≥160/110, platelets <100,000, creatinine >1.1, transaminases ≥2× normal, neurological symptoms, epigastric pain) 7

Critical Clinical Pitfalls

Transient Gestational Hypertension:

• BP elevation detected in clinic but normalizes with repeated readings over several hours 1, 2
• Carries 40% risk of progressing to true gestational hypertension or preeclampsia 1, 2
• Requires close follow-up with home BP monitoring 2

Proteinuria Does Not Define Severity:

• The degree of proteinuria does NOT correlate with disease severity or outcomes 7
• Proteinuria is used only to diagnose preeclampsia, not to classify its severity 7
• Even a single severe feature mandates management as severe disease regardless of proteinuria level 7

HELLP Syndrome:

• Represents the severe end of the preeclampsia spectrum with Hemolysis, Elevated Liver enzymes, and Low Platelets 6
• Not a separate disorder but part of severe preeclampsia 6
• Requires immediate delivery consideration 6

Epigastric or Right Upper Quadrant Pain:

• This symptom should immediately trigger suspicion for severe preeclampsia or HELLP syndrome, even without classic signs 6
• Requires urgent laboratory evaluation and abdominal ultrasound to rule out hepatic hematoma 6