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Hyperemesis Gravidarum, Emergency Medicine

Basics

Description

- Exact cause unknown - Possible causes include the following: - Elevated gestational hormone levels of human chorionic gonadotropin (hCG) and/or estradiol - Thyrotoxicosis - Upper GI motility dysfunction - Hepatic abnormalities - Autonomic nervous system dysfunction - Psychological factors - Helicobacter pylori infection - Genetic predisposition

- Peak onset is at 8 " 12 wks - Hyperemesis gravidarum is a clinical diagnosis defined by the following: - Persistent and severe nausea and vomiting - Dehydration - Weight loss of >5% of total body weight - Lab findings: Increased urine specific gravity, ketonuria, electrolyte disturbances, ketonemia

- Last menstrual period - Oral intake - Urine output - Bloody or bilious vomiting - Abdominal pain - Vaginal bleeding - Risk factors include the following: - History of motion sickness - Younger age - Migraine headaches - Symptoms earlier in the day - Low prepregnancy body mass index - More common in nulliparous women - 15% recurrence rate if manifested in previous pregnancy

- Urinalysis: - Increased specific gravity and ketonuria - Presence of glucose mandates checking serum glucose to rule out diabetes - Presence of bilirubin mandates a search to rule out hepatobiliary cause for the vomiting

- Oral rehydration in the ED after the initial fluid resuscitation and antiemetics - Thiamine 100 mg IV/IM/PO in the patient who requires IV rehydration due to case reports of Wernicke encephalopathy - Antihistamines have been shown to be effective - Methylprednisolone may be effective for patients with hyperemesis gravidarum: - Last resort - Avoid if <10 wks gestation

  • Hyperemesis gravidarum is the most severe form along the continuum of nausea and vomiting of pregnancy
  • Also known as pernicious vomiting of pregnancy
  • Characterized by unexplained intractable vomiting and dehydration
  • Occurs in 0.3 " 2% of pregnancies
  • Diagnosis of exclusion

Etiology

  • Exact cause unknown
  • Possible causes include the following:Elevated gestational hormone levels of human chorionic gonadotropin (hCG) and/or estradiolThyrotoxicosisUpper GI motility dysfunctionHepatic abnormalitiesAutonomic nervous system dysfunctionPsychological factorsHelicobacter pylori infectionGenetic predisposition

Diagnosis

Signs and Symptoms

  • Nausea and vomiting during pregnancy affects between 50% and 90%
  • Onset of symptoms by the 4th " 10th wk of pregnancy with resolution by the 20th:Symptoms after the 20th wk should raise ones suspicion of another process
  • Peak onset is at 8 " 12 wks
  • Hyperemesis gravidarum is a clinical diagnosis defined by the following:Persistent and severe nausea and vomitingDehydrationWeight loss of >5% of total body weightLab findings: Increased urine specific gravity, ketonuria, electrolyte disturbances, ketonemia

History

  • Onset of vomiting
  • Gestational history:Similar symptoms in prior pregnancies
  • Last menstrual period
  • Oral intake
  • Urine output
  • Bloody or bilious vomiting
  • Abdominal pain
  • Vaginal bleeding
  • Risk factors include the following:History of motion sicknessYounger ageMigraine headachesSymptoms earlier in the dayLow prepregnancy body mass indexMore common in nulliparous women15% recurrence rate if manifested in previous pregnancy

Physical Exam

  • Observe for signs of dehydration
  • Abdominal tenderness

Essential Workup

  • History and physical exam with special attention to state of hydration and abdominal exam for other diagnoses associated with vomiting (appendicitis, cholecystitis, etc.)
  • Obtain an uncontaminated urinalysis
  • If patient has unremitting vomiting for >24 hr, obtain a CBC, electrolytes, renal function, liver enzymes, bilirubin, and lipase

Diagnosis Tests & Interpretation

Lab

  • Urinalysis:Increased specific gravity and ketonuriaPresence of glucose mandates checking serum glucose to rule out diabetesPresence of bilirubin mandates a search to rule out hepatobiliary cause for the vomiting
  • CBC:May have an elevated hematocrit owing to dehydrationWBC is usually normal
  • Electrolytes:Elevated BUN indicating volume depletion; elevated creatinine if renal failure presentHyponatremia, hypokalemia, hypochloremia, and metabolic alkalosis from loss of HCl in emesis
  • Liver function tests:Mild increases in bilirubin may occur, but should be <4 mg/dL.AST and ALT may also be mildly elevated, but not >100 IU/L
  • Amylase/lipase:In 1 study, amylase was elevated in 24% of patients with hyperemesis gravidarum; however, the amylase was salivary in origin; use lipase rather than amylase to evaluate for pancreatitis
  • TSH
  • Serum hCG levels are not indicated if known intrauterine pregnancy

Imaging

  • US when 1st trimester US has not been performed to evaluate for:Molar pregnancyMultiple gestations

Differential Diagnosis

  • Pyelonephritis; most commonly missed
  • Gastroenteritis; gastroparesis; intestinal obstruction; Mallory " Weiss tear
  • Hepatobiliary disease; hepatitis, cholecystitis, fatty liver of pregnancy, achalasia
  • Pancreatitis
  • Appendicitis
  • Diabetic ketoacidosis
  • Hyperthyroidism; hyperparathyroidism
  • Uremia; persistent nausea and vomiting are seen with severe renal dysfunction.
  • Pseudotumor cerebri

Treatment

Pre-Hospital

  • IV, monitor if signs of significant volume depletion
  • IV hydration

Initial Stabilization/Therapy

IV hydration using a crystalloid solution (LR or NS)

Ed Treatment/Procedures

  • IV hydration using LR or NS
  • Dextrose may be added to help break cycle of ketosis
  • Treat until patient is no longer symptomatic from hypovolemia
  • Antiemetics administered IV are given to break the vomiting cycle
  • Most commonly used medications:Metoclopramide:Promethazine and prochlorperazine:Both FDA category CRecent FDA warning regarding complications of IV promethazine administrationOndansetron:FDA category B with recent warning about the risk of prolonged QT syndrome and the recommendation for ECG monitoring of the patient with electrolyte abnormalities such as hypokalemia or hypomagesemiaThese have been used extensively in pregnancy, and there is little or no evidence associated with increased risk of congenital anomaliesAntiemetics are preferable to the risk of prolonged ketosis and hypovolemia
  • Oral rehydration in the ED after the initial fluid resuscitation and antiemetics
  • Thiamine 100 mg IV/IM/PO in the patient who requires IV rehydration due to case reports of Wernicke encephalopathy
  • Antihistamines have been shown to be effective
  • Methylprednisolone may be effective for patients with hyperemesis gravidarum:Last resortAvoid if <10 wks gestation

Medication

First Line

  • Metoclopramide (category B): 10 " 20 mg IV
  • Ondansetron (category B): 4 " 8 mg IV or 4 mg PO or ODT every 8 hr
  • Prochlorperazine (category C): 5 " 10 mg IV not to exceed 40 mg/d
  • Promethazine (category C): 12.5 " 25 mg IM
  • Discharge outpatient medications:Meclizine (category B): 25 mg PO q6h PRNMetoclopramide (category B): 10 mg PO q6 " 8h PRNProchlorperazine (category C): 5 " 10 mg PO q6h or 25 mg PR q12h PRNPromethazine (category C): 12.5 " 25 mg PO or PR q4 " 6h PRNPyridoxine (vitamin B6; category A): 25 mg PO TID (OTC)Ginger (Zingiber officinale): 500 " 1500 mg div. bid/tidDoxylamine (Unisom " OTC) 12.5 mg PO q6 " 8h usually with pyridoxine (vitamin B6)Thiamine: 50 mg PO per day for symptoms >3 wks

Second Line

Methylprednisolone (category C): 16 mg IV or PO q8h 3 days and then taper. Should be prescribed in consultation with obstetrician.

Follow-Up

Disposition

Admission Criteria

  • Inability to tolerate oral intake after treatment
  • Inability to control the emesis despite treatment
  • Severe electrolyte or metabolic disturbances
  • At highest risk <8 wk gestation

Discharge Criteria

  • Most patients can be discharged as long as they are able to tolerate oral intake and have adequate follow-up
  • Correction of dehydration and associated symptoms
  • Decreased ketonuria
  • Reassure patient that their symptoms are common and usually self-limited
  • Patients should be counseled that frequent, small meals may be helpful:Meals should contain simple carbohydrates and be low in fatsAvoid irritant or spicy foods
  • Home IV therapy can be arranged if indicated

Follow-Up Recommendations

  • All patients with diagnosis should take at least 3 mg thiamine/day to help prevent Wernicke encephalopathy; a supplement of 50 mg/day PO is recommended
  • Risk for 1st trimester fetal loss is less in women with hyperemesis

Pearls and Pitfalls

  • Other diagnoses should be explored in patients presenting after 9 wk gestation with nausea and vomiting as initial symptoms
  • The use of PICC lines has been shown to carry significantly increased risk of maternal morbidity when compared to patients managed with either NG tube or medications alone
  • Be aware of the risk for central pontine myelinosis in hyponatremia patients when replacing sodium
  • Wernicke encephalopathy is the most devastating maternal complication:Patients may not have the classic triad of ataxia, nystagmus, and dementia. Be concerned for any evidence of apathy or confusionBe sure to give patients thiamine 100 mg IV for any patient who presents with apathy or confusion

Additional Reading

  • Bottomley C, Bourne T. Management strategies in hyperemesis. Best Prac Res Clin Obstet Gynaecol. 2009;23:549 " 564.
  • Goodwin TM. Hyperemesis gravidarum. Obstet Gynecol Clin North Am. 2008;35(3):401 " 417.

Codes

ICD9

  • 643.00 Mild hyperemesis gravidarum, unspecified as to episode of care or not applicable
  • 643.10 Hyperemesis gravidarum with metabolic disturbance, unspecified as to episode of care or not applicable

ICD10

  • O21.0 Mild hyperemesis gravidarum
  • O21.1 Hyperemesis gravidarum with metabolic disturbance

SNOMED

  • 14094001 Excessive vomiting in pregnancy (disorder)
  • 199025001 hyperemesis gravidarum with metabolic disturbance (disorder)
  • 19569008 Mild hyperemesis gravidarum
  • 129597002 Moderate hyperemesis gravidarum