What is gastroparesis?
It was once considered to be a rare complication of diabetes mellitus. It was believed to occur occasionally in individuals who had longstanding diabetes mellitus complicated by autonomic neuropathy. With the development of gastric emptying scans and other similar modern techniques which assesses the function of the stomach more people are being diagnosed with this problem.
Literally, gastroparesis means incomplete or partial paralysis of the stomach. It is a disorder of emptying of stomach without any evidence of mechanical obstruction. Emptying of stomach involves storage of ingested food, mixing with gastric secretions, grinding of solid food into particles 1–2 mm in diameter and the regulated delivery of this into the small intestine at a rate designed to optimize digestion and absorption. Emptying of stomach is controlled by nerves that are located in the stomach wall, spinal cord and brain, which are part of nervous system called autonomic nervous system. The nerve that controls the stomach is called the vagus nerve.
When these functions are affected it results in delayed emptying of stomach also called as gastroparesis. Diabetes mellitus is the most common cause of gastroparesis.
Causes of gastroparesis
Gastroparesis is not a specific disease. It is a disorder of emptying of stomach which can occur due to various causes. The list includes
- Gastrointestinal disorder
- Peptic ulcer disease
- Endocrine (hormonal) disorder
- Collagen vascular disease
- Post-surgical disorders
- Vagotomy ( the vagus nerve is cut)
- Fundoplication ( antireflux surgery)
- Gastric bypass surgery
- Medications for controlling high blood pressure like nifedipine
- Anti-asthma medications like Albuterol
- Antiulcer medications like aluminum hydroxide
- Anorexia nervosa
- Unknown cause
Diabetes mellitus and gastroparesis
Diabetes mellitus can cause a spectrum of abnormalities on the function of stomach. It includes accelerated emptying, delayed gastric emptying and abnormal gastric sensation. Delayed gastric emptying or gastroparesis is a well known complication of diabetes. It is usually associated with longstanding Type 1 diabetes mellitus. About 30-60% of type 1 diabetics are affected by gastroparesis. It occurs due to diabetes affecting the autonomic nervous system. Gastroparesis can occur in Type 2 diabetics also.
In most of the diabetics the vagus nerve which controls the stomach is affected. But in few individuals the vagus may be normal and gastroparesis directly correlates with the blood glucose level, with the blood glucose level exceeding 270 mg/dl resulting in gastroparesis. The symptoms of gastroparesis in the latter situation improve when the blood glucose is brought under control.
Symptoms of diabetic gastroparesis
In longstanding diabetics, delayed emptying of solid food item is common. Most of the times this does not produce any symptoms. Even in individuals who become symptomatic, it may not be persistent. It runs a fluctuating course with episodes of pronounced symptoms interspersed with relative symptom–free intervals. This fluctuation may be due to infections and variation in blood sugar levels.
Symptom severity, however, does not necessarily correlate well with the degree of gastroparesis. The various symptoms of diabetic gastroparesis are
- Fullness of stomach after food
- Abdominal bloating
- Abdominal distention
- Vomiting which can occur immediately after food or can be delayed. Delayed emptying is more suggestive of gastroparesis.
- Abdominal pain
How diabetic gastroparesis is diagnosed?
Diabetes mellitus is one of the causes of gastroparesis. The tests done to diagnose gastroparesis are the same irrespective of the cause of gastroparesis. An upper gastrointestinal endoscopy should be done first to rule out mechanical obstruction of the stomach.
If in a person with longstanding diabetes the above mentioned symptoms are present, then the following tests may be done for evaluation.
(a) Measurement of gastric emptying
(b) Measurement of gastric intraluminal pressures or contractions
(c) Measurement of gastric myoelectrical activity
Measurement of gastric emptying
Scintigraphic measurement of gastric emptying is the most accurate and arguably, the only clinically useful assessment of gastric motility at present. Scintigraphy also allows the assessment of food distribution in the stomach and the frequency and amplitude of contractions of the stomach.
Ultrasound (Doppler) scan
This is only suited to measurement of gastric emptying of liquids. It measures stomach emptying, contractions and volume.
Carbon breath tests
Carbon breath tests have recently been used to quantify solid and liquid gastric emptying. It will prove to be useful as a screening test for gastroparesis.
Magnetic resonance imaging (MRI)
MRI measures stomach emptying, contractile activity and stomach volume.
Measurement of gastric intraluminal pressures or contractions
Manometry is a complex technique which can be used to record pressures in various parts of the stomach.
Contractions can also be measured with ultrasound, scintigraphy, MRI, Single photon-emission computed tomography (SPECT).
Measurement of gastric myoelectrical activity
Electrogastrography also called EGG measures the electrical activity. It indirectly measures the function of stomach. It is similar to EKG which measures the activity of heart.
Treatment of diabetic gastroparesis
The primary goals of treatment in gastroparesis of any cause are:
- Restoring nutritional status
- Providing symptomatic relief
- Improving emptying of stomach
Restoring nutritional status
Many patients with gastroparesis are nutritionally impaired. A low fat, low fiber, soft diet with frequent small meals should be initiated.
Providing symptomatic relief
Nausea usually persists for sometime even after the treatment of gastroparesis is started. Medications that control nausea and vomiting are useful in this regard. This includes medications like
- Promethazine (Phenargan)
- Scopolamine patch
- Odansetron (Zofran)
- Granisetron (Kytril)
Improving emptying of stomach
There is a group of medications called the prokinetics. These help in the emptying of stomach. The various prokinetics that are commonly used are –
- Metaclopromide (Reglan)
- Domperidone (Motilium)
- Tegaserod (Zelnorm)
In addition to the above mentioned treatment, adequate control of blood glucose should be done as blood level of glucose also influences the course of the disease.
If there is no improvement in spite of the above mentioned treatment the following options are available-
- Gastric electrical stimulator – It is a pacemaker which stimulates the stomach
- Surgery – Feeding jejunostomy
- Endoscopic therapy – Percutaneous endoscopic jejunostomy (PEJ)
- Botulinum toxin injection
- Sildenafil citrate