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Emergency And Acute Medicine-Hyperemesis Gravidarum
Basics
Description Hyperemesis gravidarum is the most severe form of nausea and vomiting of pregnancy, also known as pernicious vomiting of pregnancy. It is characterized by persistent, unexplained vomiting leading to dehydration and metabolic disturbances. It occurs in approximately 0.3–2% of pregnancies and is a diagnosis of exclusion.
Etiology The exact cause is unknown. Proposed mechanisms include elevated levels of hCG and estradiol, thyrotoxicosis, upper gastrointestinal motility disorders, hepatic dysfunction, autonomic nervous system abnormalities, psychological factors, Helicobacter pylori infection, and genetic predisposition.
Diagnosis
Signs and symptoms Nausea and vomiting affect 50–90% of pregnancies, typically beginning between 4–10 weeks and resolving by 20 weeks. Symptoms peaking at 8–12 weeks are typical; onset after 20 weeks suggests an alternate diagnosis. Hyperemesis gravidarum is defined by severe, persistent vomiting, dehydration, and weight loss exceeding 5% of prepregnancy weight, often accompanied by ketonuria, ketonemia, electrolyte abnormalities, and elevated urine specific gravity.
History Assess onset and duration of vomiting, gestational age, prior similar pregnancies, last menstrual period, oral intake, urine output, presence of bloody or bilious emesis, abdominal pain, and vaginal bleeding. Risk factors include motion sickness, migraines, younger maternal age, low prepregnancy BMI, nulliparity, early-day symptom predominance, and a 15% recurrence risk in subsequent pregnancies.
Physical exam Evaluate hydration status and abdominal tenderness.
Essential workup Perform focused history and physical examination emphasizing hydration status and exclusion of alternative causes such as appendicitis or cholecystitis. Obtain uncontaminated urinalysis. If vomiting persists beyond 24 hours, obtain CBC, electrolytes, renal function tests, liver enzymes, bilirubin, and lipase.
Diagnosis tests and interpretation
Laboratory Urinalysis typically shows elevated specific gravity and ketonuria. Glucosuria warrants serum glucose testing; bilirubinuria prompts hepatobiliary evaluation. CBC may show hemoconcentration; WBC count is usually normal. Electrolytes may reveal elevated BUN, creatinine, hyponatremia, hypokalemia, hypochloremia, and metabolic alkalosis. Liver enzymes and bilirubin may be mildly elevated but should remain <100 IU/L and <4 mg/dL, respectively. Amylase may be elevated due to salivary origin; lipase is preferred to assess pancreatitis. TSH may be abnormal. Serum hCG levels are not indicated if an intrauterine pregnancy is confirmed.
Imaging Ultrasound is indicated if first-trimester imaging has not been performed to evaluate for molar pregnancy or multiple gestations.
Differential diagnosis Pyelonephritis, gastroenteritis, gastroparesis, bowel obstruction, Mallory–Weiss tear, hepatobiliary disease, pancreatitis, appendicitis, diabetic ketoacidosis, hyperthyroidism, hyperparathyroidism, uremia, and pseudotumor cerebri.
Treatment
Prehospital Initiate IV access and monitoring if significant volume depletion is suspected.
Initial stabilization/therapy Begin IV crystalloid hydration with normal saline or lactated Ringer’s solution.
Emergency department management Continue IV hydration; add dextrose to interrupt ketosis if indicated. Administer IV antiemetics to break the vomiting cycle. Transition to oral rehydration once symptoms improve. Thiamine 100 mg IV/IM/PO should be given to patients requiring IV fluids to prevent Wernicke encephalopathy. Antihistamines may be effective. Methylprednisolone may be considered as a last resort and should be avoided before 10 weeks’ gestation.
Medication First line Metoclopramide 10–20 mg IV; ondansetron 4–8 mg IV or 4 mg PO/ODT q8h; prochlorperazine 5–10 mg IV (max 40 mg/day); promethazine 12.5–25 mg IM. Outpatient options include meclizine 25 mg PO q6h PRN, metoclopramide 10 mg PO q6–8h PRN, prochlorperazine PO or PR, promethazine PO or PR, pyridoxine 25 mg PO TID, ginger supplements, doxylamine 12.5 mg PO q6–8h (often combined with pyridoxine), and thiamine 50 mg PO daily for symptoms lasting >3 weeks. Second line Methylprednisolone 16 mg IV or PO q8h for 3 days with taper, prescribed in consultation with obstetrics.
Follow-up and disposition
Admission criteria Inability to tolerate oral intake, persistent vomiting despite therapy, severe electrolyte or metabolic derangements, or early gestation (<8 weeks) with severe disease.
Discharge criteria Tolerance of oral intake, correction of dehydration, improvement in symptoms, and reduced ketonuria with reliable follow-up. Counsel patients on small, frequent meals rich in carbohydrates and low in fat; avoid spicy or irritant foods. Home IV therapy may be arranged if necessary.
Follow-up recommendations All patients should receive at least 3 mg of thiamine daily; 50 mg PO daily is recommended. The risk of first-trimester fetal loss is lower in women with hyperemesis gravidarum.
Key points Consider alternative diagnoses when nausea and vomiting begin after 9 weeks’ gestation. PICC lines are associated with increased maternal morbidity compared with enteral or medication-based management. Correct hyponatremia cautiously to avoid central pontine myelinolysis. Wernicke encephalopathy is a rare but severe complication and may present without classic features; administer thiamine promptly in any patient with confusion or apathy.
Basics
Description Hyperemesis gravidarum is the most severe form of nausea and vomiting of pregnancy, also known as pernicious vomiting of pregnancy. It is characterized by persistent, unexplained vomiting leading to dehydration and metabolic disturbances. It occurs in approximately 0.3–2% of pregnancies and is a diagnosis of exclusion.
Etiology The exact cause is unknown. Proposed mechanisms include elevated levels of hCG and estradiol, thyrotoxicosis, upper gastrointestinal motility disorders, hepatic dysfunction, autonomic nervous system abnormalities, psychological factors, Helicobacter pylori infection, and genetic predisposition.
Diagnosis
Signs and symptoms Nausea and vomiting affect 50–90% of pregnancies, typically beginning between 4–10 weeks and resolving by 20 weeks. Symptoms peaking at 8–12 weeks are typical; onset after 20 weeks suggests an alternate diagnosis. Hyperemesis gravidarum is defined by severe, persistent vomiting, dehydration, and weight loss exceeding 5% of prepregnancy weight, often accompanied by ketonuria, ketonemia, electrolyte abnormalities, and elevated urine specific gravity.
History Assess onset and duration of vomiting, gestational age, prior similar pregnancies, last menstrual period, oral intake, urine output, presence of bloody or bilious emesis, abdominal pain, and vaginal bleeding. Risk factors include motion sickness, migraines, younger maternal age, low prepregnancy BMI, nulliparity, early-day symptom predominance, and a 15% recurrence risk in subsequent pregnancies.
Physical exam Evaluate hydration status and abdominal tenderness.
Essential workup Perform focused history and physical examination emphasizing hydration status and exclusion of alternative causes such as appendicitis or cholecystitis. Obtain uncontaminated urinalysis. If vomiting persists beyond 24 hours, obtain CBC, electrolytes, renal function tests, liver enzymes, bilirubin, and lipase.
Diagnosis tests and interpretation
Laboratory Urinalysis typically shows elevated specific gravity and ketonuria. Glucosuria warrants serum glucose testing; bilirubinuria prompts hepatobiliary evaluation. CBC may show hemoconcentration; WBC count is usually normal. Electrolytes may reveal elevated BUN, creatinine, hyponatremia, hypokalemia, hypochloremia, and metabolic alkalosis. Liver enzymes and bilirubin may be mildly elevated but should remain <100 IU/L and <4 mg/dL, respectively. Amylase may be elevated due to salivary origin; lipase is preferred to assess pancreatitis. TSH may be abnormal. Serum hCG levels are not indicated if an intrauterine pregnancy is confirmed.
Imaging Ultrasound is indicated if first-trimester imaging has not been performed to evaluate for molar pregnancy or multiple gestations.
Differential diagnosis Pyelonephritis, gastroenteritis, gastroparesis, bowel obstruction, Mallory–Weiss tear, hepatobiliary disease, pancreatitis, appendicitis, diabetic ketoacidosis, hyperthyroidism, hyperparathyroidism, uremia, and pseudotumor cerebri.
Treatment
Prehospital Initiate IV access and monitoring if significant volume depletion is suspected.
Initial stabilization/therapy Begin IV crystalloid hydration with normal saline or lactated Ringer’s solution.
Emergency department management Continue IV hydration; add dextrose to interrupt ketosis if indicated. Administer IV antiemetics to break the vomiting cycle. Transition to oral rehydration once symptoms improve. Thiamine 100 mg IV/IM/PO should be given to patients requiring IV fluids to prevent Wernicke encephalopathy. Antihistamines may be effective. Methylprednisolone may be considered as a last resort and should be avoided before 10 weeks’ gestation.
Medication First line Metoclopramide 10–20 mg IV; ondansetron 4–8 mg IV or 4 mg PO/ODT q8h; prochlorperazine 5–10 mg IV (max 40 mg/day); promethazine 12.5–25 mg IM. Outpatient options include meclizine 25 mg PO q6h PRN, metoclopramide 10 mg PO q6–8h PRN, prochlorperazine PO or PR, promethazine PO or PR, pyridoxine 25 mg PO TID, ginger supplements, doxylamine 12.5 mg PO q6–8h (often combined with pyridoxine), and thiamine 50 mg PO daily for symptoms lasting >3 weeks. Second line Methylprednisolone 16 mg IV or PO q8h for 3 days with taper, prescribed in consultation with obstetrics.
Follow-up and disposition
Admission criteria Inability to tolerate oral intake, persistent vomiting despite therapy, severe electrolyte or metabolic derangements, or early gestation (<8 weeks) with severe disease.
Discharge criteria Tolerance of oral intake, correction of dehydration, improvement in symptoms, and reduced ketonuria with reliable follow-up. Counsel patients on small, frequent meals rich in carbohydrates and low in fat; avoid spicy or irritant foods. Home IV therapy may be arranged if necessary.
Follow-up recommendations All patients should receive at least 3 mg of thiamine daily; 50 mg PO daily is recommended. The risk of first-trimester fetal loss is lower in women with hyperemesis gravidarum.
Key points Consider alternative diagnoses when nausea and vomiting begin after 9 weeks’ gestation. PICC lines are associated with increased maternal morbidity compared with enteral or medication-based management. Correct hyponatremia cautiously to avoid central pontine myelinolysis. Wernicke encephalopathy is a rare but severe complication and may present without classic features; administer thiamine promptly in any patient with confusion or apathy.
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