Obstetrics and Gynecology Quiz on Preeclampsia

Hypertension Medications

• Hypertension medications are used to treat high blood pressure.
• Various terms are used to describe different stages and severities of high blood pressure.
• Normotension: SBP < 120 and DBP < 80
• Prehypertension: SBP > 120 but < 140 or DBP > 80
• Stage 1 Hypertension: SBP > 140 but < 160 or DBP > 90 but < 100
• Stage 2 Hypertension: SBP > 160 or DBP > 100
• Hypertensive Urgency: Markedly elevated hypertension with no evidence of end-organ involvement
• Hypertensive Emergency: Hypertension with evidence of end-organ involvement

Blood Pressure Regulation

• Two mechanisms regulate blood pressure:
• Baroreceptor: acts quickly
• Renin-angiotensin: acts in the long term

Classification of Diuretic Drugs

• Diuretic drugs are used in renal disorders.
• Categorized based on whether they modify salt excretion or water excretion
• PCT, TAL, DCT, CCT, Osmotic diuretics, ADH agonists, ADH antagonists, Loop diuretics, Carbonic anhydrase inhibitors, Thiazides, K+-sparing diuretics.

Diuretics (Thiazides)

• Examples: Hydrochlorothiazide, Chlorthalidone, Metolazone
• Mechanism of action: Inhibit Na+ sodium reabsorption in the distal tubule

Thiazides in Hypertension

• First-line treatment for postmenopausal women or those with osteoporosis.
• Potential side effects: Hyponatremia, Hypokalemia, Hyperglycemia, Hyperuricemia, Hyperlipidemia, Hypercalcemia

Loop Diuretics

• Examples: Furosemide, Bumetanide, Torsemide, Etacrynic acid
• Mechanism of action: Inhibits sodium reabsorption in the ascending loop of Henle
• Third-line treatment for severe hypertension, including cases with kidney failure or abdominal/pulmonary edema

Loop Diuretics - Side Effects

• Hypokalemia (hypokalemic metabolic alkalosis)
• Hyperuricemia
• Hypocalcemia
• Hypomagnesemia
• Ototoxicity
• Allergic reactions

Potassium-Sparing Diuretics

• Aldosterone antagonist: Spironolactone
• Non-antagonists of aldosterone: Amiloride, Triamterene
• Mechanism of action: Reduces sodium reabsorption in the collecting ducts, reducing potassium release
• Do not affect blood pressure
• Prevent potassium excretion in loop diuretic and thiazide use
• Potential side effects: Hyperkalemia, Gynecomastia, Women's menstrual disorders, Inflammation and kidney stones (Triamterene)

Inhibitors of the Adrenergic System

• Centrally acting adrenergic blocking drugs
• Ganglion blocking drugs (Mecamylamine)
• Adrenergic neuron blocking drugs (Reserpine)
• Adrenergic receptor antagonists (alpha or beta blockers)

Central Adrenergic Blocking Drugs (Methyldopa)

• Decreases central (CNS) sympathetic outflow
• Stimulates central alpha-2 receptors controlling the vasomotor center of the medulla
• L-dopa analog; produces alpha-methyl norepinephrine
• Used in chronic hypertension during pregnancy
• Potential side effects: Sedation, depression, sleep disturbance, nightmare, orthostatic hypotension, increased prolactin secretion, bone marrow suppression, bradycardia, headache, tolerance

Preeclampsia & Eclampsia

• Multisystem disorder characterized by elevated blood pressure (above 130/90 mm Hg) and proteinuria (300 mg or more in 24 hours) after the 20th week of pregnancy.
• Eclampsia: Preeclampsia with seizures.
• Serious risks for both the fetus and mother, including intrauterine growth restriction, premature birth, and death.

Preeclampsia & Eclampsia - Management

• Management depends on gestational duration
• Near term and certain fetal maturity: induction of labor advised
• Earlier gestational stage: bed rest, prolonged hospitalization, antihypertensive drugs, anticonvulsant prophylaxis
• Severe cases: delivery is the definitive intervention
• Postponed delivery: labetalol is the drug of choice for lowering blood pressure IV bolus

Preeclampsia & Eclampsia - Prophylaxis

• Because severe preeclampsia can turn into eclampsia
• Magnesium sulfate is the preferred drug for seizure control
• Initial dose: 4-6 gm IV loading followed by 5 gm IM every 4 hours or continuous IV infusion (1-2 gm/hr)

Central Adrenergic Blocking Drugs (Clonidine)

• After IV injection, clonidine briefly increases then more prolonged hypotension
• Acts on alpha adrenoceptors in arterioles
• After oral usage, reduces sympathetic and increases parasympathetic tone resulting in BP lowering and bradycardia
• Binds to imidazoline receptors to mediate antihypertensive effects.
  • Side effects: Dry mouth, sedation
  • Should not be used in people at risk for mental depression.
  • Withdrawn if depression occurs during therapy.
  • Concomitant treatment with tricyclic antidepressants can block antihypertensive effects -Withdrawal after prolonged high dosage can cause life-threatening hypertensive crisis.
  • Omitting doses can result in nervousness, tachycardia, headache, and sweating.

Adrenergic Receptor Antagonists - Alpha Blockers

• Prazosin and terazosin: selective alpha-1 antagonists
• Labetolol
• Decreased peripheral vascular resistance (vasodilation) in arteries and veins
• Sodium and water retention
• Third line of HTN
• HTN + benign prostate hyperplasia

Alpha Blocker Side Effects

• Reflex tachycardia
• Orthostatic hypotension
• Nasal congestion (increased nasal mucus volume)
• Miosis
• Other side effects of alpha-receptor blocking

Adrenergic Antagonists - Beta Blockers

• Beta-1 blockers: Atenolol, Metoprolol

• Non-selective beta-1 and -2: nadolol, propranolol, Timolol, pindolol

• Inhibits beta-1 receptors in the heart, reducing cardiac output

• Inhibits beta receptors of brain, kidney; inhibiting renin

• Second line of HTN treatment

• HTN + MI, migraine, stable angina

Beta Blockers - Side Effects

• Bradycardia
• AV Block
• CNS effects (sleep disorders, depression, nightmares)
• Worsening of asthma
• Impaired lipid profile
• Covering symptoms of hypoglycemia

Angiotensin Synthesis Inhibitors

• Captopril, Enalapril, Lisinopril
• Inhibits angiotensin-converting enzyme (ACE) that hydrolyzes angiotensin I to angiotensin II.
• Inhibit enzyme that destroys bradykinin (dilator)
• First-line treatment for hypertension
• HTN + MI, HF, Diabetes

ACE Inhibitors - Complications

• Dry cough
• Angioedema
• Hyperkalemia
• Blood pressure reduction (first use)
• Acute kidney failure
• Prohibited in pregnancy

Angiotensin II Receptor Blockers (ARBs)

• Valsartan, Saralasin, losartan
• Inhibits angiotensin II receptors.
• Similar side effects to ACE inhibitors without dry cough
• Increased possibility of fetal malformations in pregnancy

Calcium Channel Blockers

• Dihydropyridine (nifedipine, amlodipine)
• Non-Dihydropyridine (verapamil, diltiazem)
• Blocks calcium entry into smooth muscle of arteries (vasodilation)
• Decreased heart rate and contractility
• First-line treatment
  • HTN + angina, asthma, supraventricular arrhythmia, hypertensive urgency

Calcium Channel Blockers - Side Effects

• Headache, hypotension, reflex tachycardia, ankle edema
• Dihydropyridine: facial flushing, drowsiness
• Non-dihydropyridine: bradycardia, weakening of the heart, heart failure, AV block, constipation

Vasodilators - Mechanisms

• Release of nitric oxide
• Reduction of calcium influx
• Hyperpolarization of cell membranes (opening of potassium channels)
• Activation of dopamine receptors

Vasodilators

• Oral: Hydralazine, Minoxidil (long-term outpatient high blood pressure)
• Injectable: Nitroprusside, Fenoldopam (hypertensive emergencies)
• Calcium channel blockers
• Nitrates (ischemic heart disease, sometimes hypertensive emergencies)

Vasodilators - Minoxidil & Hydralazine

• Minoxidil: releases NO; opens ATP-dependent potassium channels; third line of treatment, hairiness, fluid accumulation around the heart
• Hydralazine: lupus-like syndrome (idiosyncratic), positive Coombs test; first six months of treatment

Vasodilators - Sodium Nitroprusside

• Treatment for hypertensive emergencies and severe heart failure.
• Releases nitric oxide (activates guanylyl cyclase).
• In the absence of heart failure: lowers blood pressure via decreased vascular resistance
• Light-sensitive, needs preparation before use, covered with opaque foil
• Most serious toxicity: cyanide accumulation
• Treatment with sodium thiosulfate and hydroxycobalamin
• Thiocyanate toxicity (weakness, disorientation, psychosis, muscle spasms, seizures)

Vasodilators - Fenoldopam

• Peripheral arteriolar dilator for emergencies and postoperative hypertension.
• Agonist of dopamine D1 receptors; dilates peripheral arteries and causes natriuresis.
• Short half-life (10 minutes); continuous IV infusion
• Side effects: Reflex tachycardia, headache, and flushing
• Avoid in patients with glaucoma (increases intraocular pressure)

Vasodilators - Diazoxide

• Effective, long-acting potassium channel opener; causes hyperpolarization in smooth muscle and pancreatic β cells.
• Arteriolar dilating property, formerly used parenterally for emergency cases
• High dose (300 mg rapid injection)
• Inhibits insulin release from the pancreas
• Oral dosage for hypoglycemia: 3-8 mg/kg/day in 3 divided doses, with a max of 15 mg/kg/day;
• Major toxicity from parenteral use: excessive hypotension
• Hyperglycemia can complicate diazoxide use, especially in renal insufficiency
• Causes renal salt and water retention

Test your knowledge on the management and characteristics of preeclampsia in this obstetrics and gynecology quiz. Questions cover the use of medications, side effects, and treatment options related to severe preeclampsia and eclampsia. Perfect for medical students and healthcare professionals.