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Hyperemesis Gravidarum

Hyperemesis Gravidarum

While morning sickness can occur in up to 70% of all pregnancies, it is usually more troublesome than serious. The more severe and disturbing condition, hyperemesis gravidarum, may complicate up to .3% of pregnancies, causing physiological changes that may effect the mother and fetus. Maternal weight loss, dehydration, electrolyte imbalances, acid-base disturbances leading to renal and hepatic injury have all been reported in extreme cases. Persistent vomiting can lead to Mallory-Weiss tears and nutritional deficiencies may lead to Wernicke’s encephalopathy.  

Prematurity, low birth weight and a slight increase of central nervous system and integumentary malformations have been reported in fetuses of mothers affected with hyperemesis gravidarum. An increase risk of testicular cancer in male patients of mothers with hyperemesis gravidarum during their pregnancy has also been reported in the urology literature.  

Hyperemesis gravidarum should be considered when all other causes of persistent nausea and vomiting have been ruled out. Pyelonephritis, pancreatitis, cholecystitis, hepatitis, appendicitis, gastroenteritis, peptic ulcer disease, thyrotoxicosis, and hyperthyroidism can present in similar fashions, with intractable nausea and vomiting, and are treatable conditions. Late presenters need also to be ruled out for HELLP syndrome and other causes of hepatic and central nervous system dysfunction.  

The etiology of hyperemesis gravidarum is not well understood. Hormonal causes related to human chorionic gonadotropin, estradiol, progesterone, adrenal hormones and pituitary hormones have been proposed, but currently there is no conclusive evidence implicating any specific substance. Psychological and social factors influence this disease, such as in unwanted pregnancies, although this syndrome is not limited to unwanted pregnancies. Young, unwed mothers whom are felt to have "sinned" and therefore harassed by their parents, are common sufferers of this syndrome. Remarkable improvement with hospitalization is often noted in such cases, with rapid relapses once released to the home environment. Hysterical and immature personalities can predispose one to this condition. 

The diagnostic work-up must always start with confirmation of a viable, intrauterine pregnancy. Gestational trophoblastic neoplasia can present with hyperemesis gravidarum in up to 30% of cases. Electrolytes, liver function tests, thyroid function tests, creatinine, blood urea nitrogen, urinalysis and a complete blood count are some of the studies that need consideration in the work-up. 

Once the diagnosis is made, treatment consists of mainly supportive care. Intravenous fluid, up to 5 to 6 liters per day using the appropriate amounts of sodium, potassium, chloride, lactate or bicarbonate, glucose and water, are primarily used in correcting the hypovolemia, electrolyte and acid-base imbalances, and ketosis,. Until vomiting is controlled, these patients should be maintained as NPO. A low dose, continuous infusion of an antiemetic, such as promethazine, can have beneficial effects. Vitamins, including thiamine, can be added to supplement the intravenous fluids. Patients should be maintained NPO for at least 48 hours after all symptoms and vomiting have ceased, to prevent rapid regress. Initiate PO intake with neutral fluids and a small, bland, dry, carbohydrate diet, in frequent intervals. Avoid noxious stimuli such as unpleasant odors. Reassurance and emotional support is important at this time, and psychological counseling can be initiated once symptoms have abated. 

Patients with intractable, prolonged vomiting may be treated with nasogastric enteral feedings, peripheral parenteral nutrition, or total parenteral nutrition. Rarely is interruption of pregnancy necessary. 

Oral medications have long been the main stay of out-patient treatment. Until forced off the market Bendectin (pyridoxine-vitamin B-6 (10mg) and doxylamine succinate (10 mg)), a category B medication, was efficacious and safe for both mother and fetus. This formula can be reproduced over-the-counter using Unisom Nighttime Sleep Aid (25 mg) (not Maximum Strength Unisom Sleepgels, which contains diphenhydramine hydrochloride) one half tablet and Vitamin B-6 (25 mg) one half tablet, each in the morning and afternoon, and one tablet each at bedtime, as needed. Useful category C medications are prochlorperazine, promethazine, trimethobenzamide, and droperidol., although because of their category designation, informed consent should be obtained on all patients treated with the above medications.

References

References
1. Briggs G, Freeman R, Yaffe S: Drugs in Pregnancy and Lactation, 2nd edition. Baltimore, Williams and Wilkins, 1986
2. Creasy R, Resnik R: Maternal-Fetal Medicine: Principles and Practice, 2nd edition. Philadelphia, W.B. Saunders, 1989
3. Gabbe S, Neibyl J, Simpson J; Obstetrics: Normal and Problem Pregnancies, 2nd edition, Churchill Livingstone, 1991
4. Cunningham F, MacDonald P, Gant N: Williams Obstetrics, 18th edition. Appleton and Lange, 1989
5. Greenspoon J, Rosen D, Ault M: Use Of The Peripherally Inserted Central Catheter For Parenteral Nutrition During Pregnancy. Obstetrics and Gynecology 1993;81:831-4
6. Hsu J, Clark-Glena R, Nelson D, Kim C: Nasogastric Enteral Feeding In The Management Of Hyperemesis Gravidarum. Obstetrics and Gynecology 1996;88:343-346

 
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