Pre-eclampsia and Spiral Arteries Quiz
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Questions and Answers

What is the typical state of the spiral arterioles by 20 weeks of gestation?

  • They are completely obliterated by trophoblast cells, preventing blood flow.
  • They are converted to wide bore, low resistance, large capacitance vessels. (correct)
  • They have moderate resistance and a small diameter.
  • They are partially invaded by trophoblast cells, partially replaced with smooth muscle.

    • What happens in Pre-eclampsia (PET) that disrupts the normal development of the spiral arteries?

  • The spiral arteries develop thrombi due to an autoimmune response.
  • The trophoblast cells fail to invade the myometrial segments of the spiral arteries. (correct)
  • The spiral arteries are abnormally constricted by excessive smooth muscle growth.
  • The spiral arteries are completely invaded by trophoblast cells, which then degenerate and obstruct the vessels.

    • What is the primary function of the trophoblast cells in the spiral arteries?

  • To stimulate blood vessel growth in the placenta.
  • To create a barrier between maternal and fetal blood.
  • To remodel the spiral arteries to increase blood flow to the placenta. (correct)
  • To produce hormones that regulate placental development.

    • What is the approximate increase in maternal blood flow to the placenta from the first trimester to term?

    <p>10-fold increase (C)</p> Signup and view all the answers

    Which of the following is NOT a consequence of the failure of trophoblast invasion in the spiral arteries?

    <p>Increased risk of placental abruption. (B)</p> Signup and view all the answers

    What is the approximate percentage of pregnancies that are complicated by pre-eclampsia?

    <p>2-3% (B)</p> Signup and view all the answers

    What is a possible reason for the reduced effectiveness of trophoblast invasion in pre-eclampsia?

    <p>Abnormal maternal immune system adaptation (B)</p> Signup and view all the answers

    Which of the following conditions increases the risk of pre-eclampsia in a subsequent pregnancy?

    <p>Severe pre-eclampsia in the first pregnancy (A)</p> Signup and view all the answers

    Which of the following is NOT a risk factor for developing pre-eclampsia?

    <p>Age under 30 years (C)</p> Signup and view all the answers

    What is the defining characteristic of spiral arteries in pre-eclampsia?

    <p>Narrow bore, low capacitance, and high resistance (B)</p> Signup and view all the answers

    What is the typical timeframe for the resolution of pre-eclampsia after delivery?

    <p>Within six weeks (A)</p> Signup and view all the answers

    Which of the following is a potential consequence of impaired perfusion of the fetoplacental unit?

    <p>Reduced fetal oxygen supply (C)</p> Signup and view all the answers

    What is the hypothesized role of the factor(s) released into the maternal circulation in pre-eclampsia?

    <p>Targeting the vascular endothelium (C)</p> Signup and view all the answers

    What is the recommended management for a patient with pre-eclampsia in its severest form?

    <p>Hospitalization, investigations, and antihypertensive/anticonvulsant therapy, followed by timed delivery (D)</p> Signup and view all the answers

    Which antihypertensive agent is known to have a long established safety record in pregnancy and can be administered orally?

    <p>Labetalol (A), Methyldopa (C)</p> Signup and view all the answers

    Which of the following is a potential concern associated with Nifedipine administration in pre-eclampsia?

    <p>Severe headache mimicking worsening disease (A)</p> Signup and view all the answers

    What is the most common cause of death in pre-eclampsia?

    <p>Intracranial hemorrhage (A)</p> Signup and view all the answers

    Which of the following interventions has been shown to modestly reduce the risk of pre-eclampsia in high-risk women?

    <p>Low-dose aspirin therapy (D)</p> Signup and view all the answers

    What is the recommended mode of delivery for pre-eclampsia patients at less than 34 weeks gestation?

    <p>Cesarean section (B)</p> Signup and view all the answers

    Why is ergometrine contraindicated in pre-eclampsia patients?

    <p>Potential for severe hypotension (B)</p> Signup and view all the answers

    Which of the following clinical situations should raise suspicion of chronic hypertension or kidney disease in a woman who has recently experienced pre-eclampsia?

    <p>Persistence of hypertension and proteinuria beyond 6 weeks postpartum (D)</p> Signup and view all the answers

    What is a characteristic lesion associated with pre-eclampsia in the renal system?

    <p>Glomeruloendotheliosis (A)</p> Signup and view all the answers

    Which of the following is NOT a typical symptom of pre-eclampsia?

    <p>Frequent urination (A)</p> Signup and view all the answers

    What is the primary cause of hypertension in pre-eclampsia?

    <p>Peripheral vasoconstriction (C)</p> Signup and view all the answers

    Which of these conditions is a particularly severe form of pre-eclampsia?

    <p>HELLP syndrome (A)</p> Signup and view all the answers

    Which of the following changes is NOT characteristic of pre-eclampsia in the haematological system?

    <p>Increased red blood cell count (A)</p> Signup and view all the answers

    What is a worrying sign during clinical examination of a patient suspected of having pre-eclampsia?

    <p>Epigastric tenderness (B)</p> Signup and view all the answers

    Which neurological manifestation is more likely to be seen in hypertensive encephalopathy compared to pre-eclampsia?

    <p>All of the above (D)</p> Signup and view all the answers

    What is the primary factor contributing to the development of generalized oedema in pre-eclampsia?

    <p>Increased vascular permeability (A)</p> Signup and view all the answers

    Flashcards

    Trophoblast cells

    Cells that invade the spiral arterioles during early pregnancy.

    Spiral arterioles

    Blood vessels that supply the placenta and change during pregnancy.

    Placental blood flow

    The increase in maternal blood flow to the placenta during pregnancy.

    Trophoblast invasion failure

    A condition where trophoblast cells fail to properly invade spiral arteries.

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    Preeclampsia (PET)

    A disorder characterized by trophoblast invasion failure leading to hypertension.

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    Pre-eclampsia Management

    Includes monitoring and treating high blood pressure and preventing complications.

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    Antihypertensive Therapy

    Treatment aimed at lowering blood pressure while maintaining fetal blood flow.

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    Methyldopa

    A centrally acting antihypertensive safe for pregnancy; given orally, takes 24+ hours to work.

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    Labetalol

    An alpha- and beta-blocking agent, safe in pregnancy; can be given IV or orally.

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    Nifedipine

    A calcium-channel blocker that works quickly; can cause headaches mimicking disease progression.

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    Doppler Ultrasound

    Used to assess blood flow and identify risks for pre-eclampsia, effectiveness varies.

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    Low Dose Aspirin

    Modestly reduces pre-eclampsia risk in high-risk women.

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    Chronic Hypertension Indication

    Consider chronic hypertension if high blood pressure or proteinuria persist beyond 6 weeks postpartum.

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    Pre-eclampsia definition

    Hypertension (≥ 140/90 mmHg) and proteinuria after 20 weeks gestation.

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    Incidence of pre-eclampsia

    Pre-eclampsia complicates approximately 2-3% of pregnancies.

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    Primigravid women

    Pre-eclampsia is more common in women pregnant for the first time.

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    Risk factors for pre-eclampsia

    Includes first pregnancy, age 40+, high BMI, and family history.

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    Trophoblast invasion

    The process where trophoblast cells invade the spiral arteries.

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    Pathophysiology of pre-eclampsia

    Defective trophoblast invasion leads to low blood flow in placenta.

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    Placental under-perfusion

    Insufficient blood flow to the placenta due to trophoblast issues.

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    Recurrence risk

    Subsequent pregnancy risk of pre-eclampsia is 20%, higher if severe.

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    Vascular Endothelial Cell

    The target cell affected in pre-eclampsia, leading to vascular dysfunction.

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    Glomeruloendotheliosis

    A characteristic lesion in pre-eclampsia affecting kidney function.

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    Proteinuria

    Presence of excess proteins in urine, often due to kidney issues in pre-eclampsia.

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    HELLP Syndrome

    A severe form of pre-eclampsia with hemolysis, elevated liver enzymes, and low platelets.

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    Cerebral Oedema

    Swelling in the brain associated with severe cases of pre-eclampsia.

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    Hypertensive Encephalopathy

    A condition with brain dysfunction due to high blood pressure, but rare in pre-eclampsia.

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    Frontal Headache

    A common symptom of pre-eclampsia indicating increased intracranial pressure.

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    Dependent Oedema

    Swelling in the feet due to fluid accumulation, common in pregnant women, but needs watching in pre-eclampsia.

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    Study Notes

    Hypertension in Pregnancy

    • Hypertension in pregnancy is a significant medical concern.
    • The presentation, treatment, and outcomes of pregnancy-related hypertension are crucial.
    • Trophoblast cells invade spiral arterioles in the first 12 weeks, replacing smooth muscle, creating wide-bore, low-resistance vessels.
    • This process is typically complete by 20 weeks gestation.
    • Maternal blood flow to the placenta increases from 50 mL/min in the first trimester to 500-750 mL/min at term.

    Placental Disease

    • Trophoblast invasion is critical for normal placental function.
    • In pre-eclampsia, there's an incomplete or partial failure of trophoblast invasion of spiral arteries.
    • These arteries retain their pre-pregnancy characteristics; narrow bore, low capacitance, and high resistance.
    • Impaired perfusion of the fetoplacental unit results from this.

    Definition of Pre-eclampsia

    • Pre-eclampsia is defined as hypertension of at least 140/90 mmHg recorded on two separate occasions at least 4 hours apart, accompanied by at least 300 mg protein in a 24-hour urine collection.
    • It must occur de novo after 20 weeks of pregnancy in a previously normotensive woman and resolve completely by the sixth postpartum week.

    Incidence

    • Pre-eclampsia affects approximately 2-3% of pregnancies.

    Epidemiology

    • Primigravid women are more susceptible to pre-eclampsia.
    • The recurrence risk in subsequent pregnancies is 20%, but higher if the first pre-eclampsia was severe and early-onset.
    • First-degree relatives of affected women have a 3-4 times higher risk of developing pre-eclampsia.

    Risk Factors

    • First pregnancy
    • Multiparous with pre-eclampsia in a previous pregnancy (greater than 10 years after last pregnancy)
    • Age 40 years or older
    • Body mass index (BMI) of 35 or more
    • Family history of pre-eclampsia
    • Booking diastolic blood pressure of 80 mmHg or above
    • Booking proteinuria (1 or greater than 1 on more than one occasion or quantified at 0.3 g/24 hour)
    • Multiple pregnancy
    • Pre-existing hypertension, renal disease, diabetes
    • Antiphospholipid antibodies

    Pathophysiology

    • Placental bed biopsies show patchy trophoblast invasion and persistent spiral artery muscular walls in pre-eclampsia.
    • This prevents the development of a high-flow, low-impedance uteroplacental circulation.
    • The exact reason for ineffective trophoblast invasion in pre-eclampsia isn't fully understood but may relate to a defective maternal immune response.
    • Defective trophoblast invasion leads to placental underperfusion and the release of factors affecting vascular endothelium in the maternal circulation.
    • Pre-eclampsia is a multisystem disease affecting multiple organ systems.

    Cardiovascular System

    • Pre-eclampsia is characterized by peripheral vasoconstriction causing hypertension.
    • This results in elevated intravascular pressure and compromised endothelial cell integrity.
    • Resulting vasculature permeability contributes to generalized edema.

    Renal System

    • A highly distinctive lesion called glomeruloendotheliosis is associated with pre-eclampsia.
    • This is linked with impaired glomerular filtration and selective loss of intermediate proteins (e.g., albumin, transferrin), contributing to proteinuria.
    • Reduction of plasma oncotic pressure may worsen the development of edema.

    Hematological System

    • Endothelial damage and increased fibrin deposition are common in pre-eclampsia.
    • Platelet count reduction can sometimes accompany or precede the onset of the disease.

    Liver

    • Subendothelial fibrin deposition and elevated liver enzymes frequently accompany pre-eclampsia.
    • Hemolysis and low platelet count due to platelet consumption (and subsequent coagulation system activation).
    • HELLP syndrome is a severe form of pre-eclampsia, occurring in 2-4% of cases and associated with high fetal loss rates (up to 60%).

    Central Nervous System (CNS)

    • Vasospasm and cerebral edema are implicated in the pathogenesis of eclampsia (the more severe form of pre-eclampsia).
    • Retinal hemorrhages, exudates, and papilledema are characteristic of hypertensive encephalopathy but less common in pre-eclampsia.

    Clinical Presentation

    • Common symptoms of pre-eclampsia include headaches, visual disturbances, and epigastric pain.
    • Many women present with vague flu-like symptoms or remain asymptomatic early.
    • Clinical exams should include a complete obstetric and neurological assessment.
    • Hypertension is usually the first sign but may be intermittent or absent until later stages.
    • Edema of the feet is common and rapid swelling of the face and hands can be a concern.
    • Epigastric tenderness suggests liver involvement.
    • Neurological examination might reveal hyperreflexia and clonus in severe cases.
    • Protein in the urine should be assessed.

    Management

    • Early recognition of asymptomatic cases, understanding the severity, and adherence to guidelines for hospital admission, investigation, and treatment are vital.
    • Antihypertensive and anticonvulsant therapies must be implemented.
    • Planned delivery is crucial to avoid maternal or fetal complications.
    • Post-natal monitoring and counseling for subsequent pregnancies are vital.

    Management: Antihypertensive Therapy

    • Aiming to reduce blood pressure without compromising uterine blood flow and fetal well-being is essential.
    • Several antihypertensive medications are used in pregnancy, including methyldopa (centrally acting, oral onset 24 hrs later), labetalol (alpha/beta-blocker, oral/IV), and nifedipine (calcium channel blocker, rapid onset but can induce headache mimicking disease worsening)

    Management: Severe Cases

    • Intravenous infusion of hydralazine or labetalol.
    • Magnesium sulfate (a mainstay treatment).
    • Severe multisystem complications necessitate a multidisciplinary approach (intense care, hepatology, nephrology).
    • Intracranial hemorrhages are significant causes of death from pre-eclampsia.

    Screening and Prevention

    • No reliable screening test currently exists for pre-eclampsia.
    • Doppler ultrasound analysis of uterine artery waveforms may assist in identifying high-risk pregnancies but isn't universally effective.
    • Low-dose aspirin (75 mg) lowers risk in high-risk pregnancies, though benefits vary.
    • Calcium supplementation may be beneficial for women with low dietary intake.
    • Vitamin C and E do not reduce pre-eclampsia risk.

    Mode of Delivery

    • Preterm delivery (under 34 weeks gestation) usually results in cesarean section.
    • Steroids are crucial in preterm pregnancies to assist fetal lung development.
    • Prophylactic anticoagulation and compression stockings are standard.
    • Epidural or spinal analgesia is possible (with normal clotting test results).
    • Ergometrine is not used in pre-eclampsia management (contraindicated).
    • For pre-eclampsia that persists beyond 6 weeks, chronic hypertension or kidney disease evaluation is appropriate.
    • In severe cases before 34 weeks gestation, an underlying cause search is needed.

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    Hypertension In Pregnancy PDF

    Description

    Test your knowledge on the development of spiral arterioles and the implications of pre-eclampsia during pregnancy. This quiz covers critical aspects such as trophoblast functions, blood flow changes, and risk factors associated with pre-eclampsia. Perfect for students studying obstetrics or maternal-fetal medicine.

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