Basics
Description
- 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 estradiol
- Thyrotoxicosis
- Upper GI motility dysfunction
- Hepatic abnormalities
- Autonomic nervous system dysfunction
- Psychological factors
- Helicobacter pylori infection
- Genetic 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 vomiting
- Dehydration
- Weight loss of >5% of total body weight
- Lab 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 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
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 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
- CBC:
- May have an elevated hematocrit owing to dehydration
- WBC is usually normal
- Electrolytes:
- Elevated BUN indicating volume depletion; elevated creatinine if renal failure present
- Hyponatremia, 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 pregnancy
- Multiple 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 C
- Recent FDA warning regarding complications of IV promethazine administration
- Ondansetron:
- 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 hypomagesemia
- These have been used extensively in pregnancy, and there is little or no evidence associated with increased risk of congenital anomalies
- Antiemetics 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 resort
- Avoid 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 PRN
- Metoclopramide (category B): 10 mg PO q6 " 8h PRN
- Prochlorperazine (category C): 5 " 10 mg PO q6h or 25 mg PR q12h PRN
- Promethazine (category C): 12.5 " 25 mg PO or PR q4 " 6h PRN
- Pyridoxine (vitamin B6; category A): 25 mg PO TID (OTC)
- Ginger (Zingiber officinale): 500 " 1500 mg div. bid/tid
- Doxylamine (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 fats
- Avoid 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 confusion
- Be 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