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What is Gastroparesis?
Gastroparesis literally means weakness or paralysis
of the stomach. The lower portion of the stomach, or antrum which
grinds solid food, contracts poorly, or not at all. As a result
of this condition, the stomach becomes sluggish, and digests solid
food very slowly.
Symptoms
Symptoms of gastroparesis are a result of slow gastric
emptying. These include bloating, or a prolonged sensation of
fullness after eating, nausea and vomiting, loss of appetite,
and weight loss. A secondary effect of gastroparesis is excessive
acid secretion. Filling the stomach "turns on" acid
production. As the stomach digests the food and empties it into
the intestine, acid production normally slows to a low basal,
or resting, level. If the stomach does not empty, then acid production
never slows down as it should. This leads to symptoms of indigestion,
heartburn, regurgitation, and abdominal pain. These symptoms suggest
the presence of an ulcer. Many patients with gastroparesis are
initially diagnosed as having peptic ulcer disease, but usually
fail to respond completely to treatment.
What causes it?
Gastroparesis may be a primary or secondary problem.
Ulcers and tumors may cause swelling and a blockage which will not allow
food to pass out of the stomach. Vomiting which occurs with food
poisoning or intestinal flu may be a result of delayed gastric
emptying. Helicobacter infection and various drugs can also cause
delayed emptying. Hypothyroidism may also delay gastric emptying.
Gastroscopy is necessary in most cases to identify
obstruction and other potential problems, and to diagnose complications
such as esophagitis. Diabetes is the most commonly identified
disease associated with gastroparesis, but in most patients there
is no identifiable cause.
In many cases, nausea, vomiting and other symptoms
of gastroparesis may vary in severity for no apparent reason.
The response to medical treatment is also quite variable. This
may make treatment difficult at times.
Diagnosis
Gastroparesis is diagnosed using a gastric emptying
study. The patient is given a small meal containing a small amount
of radioactive tracer. A gamma camera is placed over the stomach
to measure the rate at which the stomach digests and empties the
food. If the stomach is emptying slowly, Reglan can be given to
see whether it speeds emptying. This information is sometimes
helpful, as not all patients respond to Reglan. Other more complicated
tests such as gastroduodenal motility studies and electrogastrography
are being performed in research centers. These tests have helped
us to better understand this disease, but are not required in
the management of most patients.
Treatment
Reglan (metoclopramide) was the first drug released
for treatment of gastroparesis. Reglan increases the muscular
contraction of the stomach and speeds gastric emptying. It also
strengthens the valve muscle at the lower end of the esophagus
to reduce regurgitation and heartburn. The drug also has a direct
effect on the brain to reduce nausea and vomiting. About ten percent
of patients have side effects which require stopping the drug.
Common side effects include drowsiness, anxiety or shakiness,
muscle tremors or spasm, diarrhea, urinary frequency, and breast
swelling or pain.
The usual dose of Reglan is 5 to 10 mg. four time
a day, taken 30 minutes before each meal and at bedtime.
Other Drugs
Erythromycin is an antibiotic which improves gastric
emptying by simulating the effect of a natural gut hormone called motilin. It is most effective if given intravenously. We have
treated a number of patients with liquid erythromycin suspension
given orally with variable results. Research is being done to
develop similar compounds which can be used to treat gastroparesis
Cisapride (Propulsid) is no longer available for treatment of gastroparesis. It
was withdrawn from the market because of reports of sudden cardiac deaths. Drugs
to reduce acid secretion may also alleviate some of the symptoms of
gastroparesis. When the stomach remains full, acid is produced almost
continuously. Fluid is also secreted into the stomach along with the acid and
may contribute to fullness, bloating and vomiting. Tagamet, Zantac and other
H2RAs (Histamine receptor antagonists) are usually not potent enough to turn off
the acid in this condition. Most patients require a PPI (proton pump inhibitor)
such as Prilosec, Prevacid, Aciphex, or Protonix, sometimes in rather high
doses.
Antiemetics (drugs to relieve nausea and vomiting)
such as Phenergan, Compazine and Tigan may also be useful in controlling
the nausea and vomiting associated with this disorder. They are
most readily absorbed when given as a liquid. Suppositories may
be required to control vomiting. Because of potential side effects,
these drugs should not be given for long periods of time unless
absolutely necessary.
Diet
Diet can be very important in the management of gastroparesis.
Even while taking medication, some patients are unable to tolerate
solid foods. This is because the stomach is unable to grind the
food into particles small enough to pass into the intestine. Liquids
are emptied more passively and do not require grinding. A liquid
diet is often necessary, at least temporarily, in some patients
with gastroparesis. Fatty foods can also cause worsening of nausea,
vomiting and abdominal pain. This occurs because fats slow gastric
emptying and delay digestion. A low fat diet is beneficial, at
least for relief of symptoms. Maintaining a balanced, complete
diet is often difficult, and may require extra vitamins and other
nutritional supplements.
A few patients will require placement of a feeding
tube into the intestine in order to provide nutritional support.
Occasionally, intravenous feedings (hyperalimentation) may be
necessary. This is generally a temporary but life saving measure. |
