Structure and clinical significance of preeclampsia
Preeclampsia is not an isolated symptom, but a spectrum of pathological conditions. Traditionally, the structure of this complication includes:
- Hydramnios/dropsy of pregnant women.
- Moderate and severe preeclampsia.
- Eclampsia (the critical stage).
- HELLP syndrome.
The classic clinical picture is based on a triad of symptoms: elevated blood pressure, protein in the urine (proteinuria), and edema. Due to the high risk to the mother, induced early delivery is often required, leading to high rates of perinatal morbidity and neonatal mortality (due to prematurity).
HELLP syndrome: definition and breakdown
One of the most formidable manifestations of preeclampsia is HELLP syndrome. Its name is an acronym describing key laboratory abnormalities:
- H (Hemolysis) — destruction of red blood cells.
- EL (Elevated Liver enzymes) — increased liver enzyme activity.
- LP (Low Platelet count) — low platelet count.
Differential diagnosis: hepatic complications
If jaundice and liver dysfunction develop during pregnancy, preeclampsia and HELLP syndrome must be differentiated from other liver pathologies.
Intrahepatic cholestasis of pregnancy Manifests with heartburn, nausea, and pruritus (ranging from mild to generalized). Jaundice is moderate or absent. Blood tests reveal elevated ALT, AST, alkaline phosphatase, and direct bilirubin. Conservative management includes a diet low in fried foods, choleretic agents, essential fatty acids, and intravenous crystalloids.
Acute fatty liver of pregnancy Most commonly affects primigravidas and develops in two stages:
- Anicteric stage (2–6 weeks): asthenia, vomiting, epigastric pain, pruritus, and weight loss.
- Icteric stage: development of hepatorenal failure (oligoanuria, edema, fluid accumulation in serous cavities, bleeding, risk of antenatal fetal death, and hepatic coma).
Specific markers: hypoproteinemia (less than 6 g/L), hypofibrinogenemia (less than 200 g/L), and direct hyperbilirubinemia. Unlike HELLP syndrome, marked thrombocytopenia is atypical, and transaminases are only mildly elevated. Management: an absolute indication for emergency termination of pregnancy accompanied by intensive preparation and fresh frozen plasma infusion (at least 20 mL/kg/day).
Early gestosis: precursors of complications
Unlike preeclampsia, which manifests in the second half of gestation, early gestoses occur in the first months. They are characterized by dyspepsia and metabolic disturbances of all types.
Nausea and vomiting of pregnancy (emesis gravidarum) The pathogenesis is based on the neuro-reflex theory—dominance of excitation in subcortical CNS structures (reticular formation, medullary centers). Irradiation of impulses affects the vomiting, respiratory, vasomotor, and salivary centers. Triggering factors include high levels of human chorionic gonadotropin (hCG) and progesterone (especially in multiple pregnancies or hydatidiform mole). Progression of vomiting leads to dehydration, starvation, and hypokalemia. A hematocrit level of over 40% serves as a criterion for severe dehydration. Urine tests show a strongly positive reaction for acetone.
Ptyalism (Ptyalismus) May accompany vomiting or occur in isolation. Fluid loss through saliva reaches up to 1 liter per day, which exacerbates dehydration and leads to facial skin maceration.
Principles of therapy and indications for termination
Treatment of severe gestosis requires hospitalization, strict bedrest and protective regimen (placement in a private room to eliminate vomiting triggers), and complex infusion therapy. The infusion volume is 1–3 L/day, of which at least 30–35% is allocated to parenteral nutrition (dextrose with small doses of insulin, amino acids, fat emulsions).
If treatment for excessive vomiting is ineffective, the pregnancy must be terminated as an emergency. Criteria for termination:
- Lack of response to treatment within 3 days.
- Incessant vomiting and progressive weight loss.
- Progressive ketonuria lasting 3–4 days.
- Pronounced tachycardia and central nervous system disorders (apathy, delirium, euphoria).
- Bilirubinemia of 40–80 µmol/L (a level of 100 µmol/L is considered critical) with jaundice of the sclera and skin.
Briefly: answers to topical questions
What are the diagnostic criteria for severe preeclampsia?
Diagnostic criteria for severe preeclampsia include marked clinical and laboratory abnormalities.
| Parameter | Criterion for severe preeclampsia |
|---|---|
| Blood pressure | Systolic ≥160 mm Hg or diastolic ≥110 mm Hg |
| Oliguria | <500 ml/day (<30 ml/h) |
| Pain | Epigastric or right upper quadrant pain (+) |
| Liver function | Elevated ALT and AST |
| Platelets | <100×10⁹/L |
Neurological and dyspeptic symptoms, pulmonary edema, cyanosis, generalized edema, hemolysis, elevated creatinine, HELLP syndrome, intrauterine growth restriction, or antenatal fetal death may also be present.
What medications are used for antihypertensive therapy in preeclampsia?
Antihypertensive drugs are used for blood pressure management in preeclampsia, taking into account their fetal safety profile.
- Nifedipine — extended-release formulation.
- Amlodipine — can be added to therapy orally.
- Methyldopa — can be added to therapy orally; not recommended in the postpartum period due to an increased risk of postpartum depression.
Calcium channel blockers, adrenergic receptor agonists, vasodilators, potassium-sparing diuretics, and antispasmodics are also used.
What does magnesium sulfate therapy involve in preeclampsia and eclampsia?
Magnesium therapy involves the intravenous administration of magnesium sulfate and is the first-line treatment for the prevention and management of seizures.
- Loading dose — 4–6 g (20 mL of a 25% solution) administered over 10–15 minutes.
- Additional dose — 2 g over 3–5 minutes if no effect is observed.
- Maintenance infusion — 1–3 g/h via a syringe pump.
The infusion is continued for at least 24 hours during and after delivery; some sources recommend continuing for 24–48 hours postpartum or following the last eclamptic seizure. Monitoring of urine output (at least 30 mL/h), respiratory rate, oxygen saturation, and deep tendon reflexes is mandatory during treatment.
What fetal complications are characteristic of preeclampsia?
Preeclampsia is characterized by complications associated with impaired uteroplacental blood flow and placental insufficiency.
- Fetal growth restriction — develops as a result of compromised uteroplacental blood flow.
- Placental insufficiency — associated with impaired uteroplacental perfusion.
- Chronic fetal hypoxia — may develop in complicated pregnancies, including preeclampsia.
- Antenatal fetal death is listed among the signs of severe preeclampsia.
- Preterm birth — preeclampsia is a frequent cause of induced preterm birth.
- In early-onset preeclampsia, the risk of grade II–III fetal growth restriction and neonatal asphyxia is increased.
For quick recall of HELLP syndrome, use the acronym itself: Hemolysis, Elevated Liver enzymes, Low Platelet count.
Class and exam questions
What is the main difference between preeclampsia and early toxicosis?
Preeclampsia develops in the second half of pregnancy (after 20 weeks), during labor, or in the postpartum period, whereas early toxicoses (vomiting, sialorrhea) are characteristic of the first half of gestation.
What symptoms are included in the classical triad of preeclampsia?
The classical triad includes arterial hypertension, proteinuria (presence of protein in the urine), and edema.
How to differentiate acute fatty liver of pregnancy from HELLP syndrome based on lab tests?
Acute fatty liver of pregnancy presents with marked hypoproteinemia and hypofibrinogenemia, but without severe thrombocytopenia, and transaminases are only slightly elevated. In contrast, HELLP syndrome is characterized by a sharp drop in platelets and a significant increase in liver enzymes.
At what hematocrit level is severe dehydration diagnosed in hyperemesis gravidarum?
The criterion for marked dehydration and hemoconcentration is considered to be an increase in hematocrit levels above 40%.
What else to study on this topic
- Pathogenesis of gestational dropsy and mechanisms of edema formation
- Eclampsia: clinical presentation of seizures and emergency care
- Infusion therapy in toxicoses: calculation of volumes and selection of drugs
- Rare forms of toxicosis: dermopathy, tetany, and osteomalacia of pregnant women
- Effect of abnormally high hCG levels on the severity of toxicosis
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