So much of our daily life revolves around eating. Eating can be a very unpleasant experience for those who suffer from gastroparesis. Imagine getting sick every time you eat. Gastroparesis is a chronic, debilitating, and severe neuromuscular disorder of the stomach that results in a partially or completely paralyzed stomach.

The normal digestion process starts in the mouth where food is chewed and mixed with saliva breaking the food into pieces that can be swallowed. From there, the food is further broken down into a form that the body can absorb and use. The process ends at the anus where stool and unused food waste are eliminated from the rectum.

The autonomic nervous system controls body processes that are not under our conscious control such as the digestion process. For patients with gastroparesis, what was once functioning normally and outside their conscious awareness has now become acutely in the patient's realm of consciousness. It's hard to ignore things like nausea, vomiting, and acid reflux.

Other signs and symptoms of gastroparesis include:

  • A feeling of fullness after eating just a few bites
  • Abdominal bloating
  • Abdominal pain
  • Changes in blood sugar levels
  • Lack of appetite
  • Vomiting undigested food eaten a few hours earlier
  • Weight loss and malnutrition

Digestion time varies between individuals and between men and women. After eating, it generally takes about six to eight hours for food to pass through the stomach and small intestine. Food is moved through the digestive tract via peristalsis, which is a series of wave-like muscle contractions.

In many cases, gastroparesis is believed to be caused by damage to a nerve that controls the stomach muscles – the vagus nerve. The vagus nerve is one of 12 cranial nerves in the autonomic nervous system. It is the longest of the cranial nerves, extending from the brainstem to the abdomen.

Damage to the vagus nerve is not always the culprit leading to gastroparesis though. Often, the cause of gastroparesis is unknown or is unclear.

Other conditions known to cause gastroparesis include: uncontrolled diabetes, medications such as narcotics and some antidepressants, Parkinson's disease, multiple sclerosis, eating disorders, and rare conditions such as: amyloidosis and scleroderma.

The ICD-10-CM diagnosis code for gastroparesis is K31.84. There is a note in the Index under gastroparesis that directs the coder to see diabetes by type when coding gastroparesis. That's a wee bit tricky and can catch some coders off guard.

If the physician documents the patient has type 1 diabetes with gastroparesis and you want to assign the appropriate diagnosis code(s). If you started with the main term gastroparesis and followed the note as instructed, you would have gone to Diabetes Type 1 with gastroparesis E10.43, type 1 diabetes mellitus with diabetic autonomic polyneuropathy.

You might think you were done if you relied on the alpha Index, but as you know if you only use the Index, you are bound to make coding mistakes. Underneath code E10.43, it says, "type 1 diabetes mellitus with diabetic gastroparesis." The inexperienced coder might think that gastroparesis is an inherent part of this code. That is an incorrect assumption.

To capture the fact that the patient has gastroparesis, an additional code is needed. It is necessary to report both E10.43 as well as K31.84 in this clinical circumstance to specify that the autonomic neuropathy is gastroparesis.

Also tricky to code is a bezoar. This is undigested food in the stomach which can harden into a solid mass. Bezoars can cause nausea and vomiting and may be life-threatening if they prevent food from passing into the small intestine. Bezoars are coded as foreign bodies from ICD-10-CM code categories such as:

  • T18.2-, foreign body in stomach
  • T18.3-, foreign body in small intestine
  • T18.9-, foreign body in alimentary tract, part unspecified

Another condition you may commonly see related to gastroparesis is ileus. Ileus is the medical term for lack for movement somewhere in the intestines that leads to a buildup and potential blockage of food material. An ileus can lead to an intestinal obstruction. This means no food material, gas, or liquids can get through. It often, although certainly not always, occurs as a side effect after surgery. However, there are other causes for an ileus.

The coding of an ileus was discussed in Coding Clinic, First Quarter 2017. The article clarified that an ileus does not always result in an obstruction. When an ileus occurs postoperatively, Coding Clinic advises coders that it cannot be assumed that the ileus is a postoperative complication unless the physician's documentation supports this. If in doubt, Coding Clinic advises coders to query the physician.

If the physician confirms the ileus is a post-operative complication without obstruction, coders are advised to report K91.89, other postprocedural complications and disorders of digestive system and K56.7, ileus, unspecified.

On the other hand, if the post-operative ileus causes an obstruction and the physician documents it as a complication, Coding Clinic guidance instructs coders to use only code K91.3, postprocedural intestinal obstruction.