Caring for the patient with a disorder of the gastrointestinal system

4 Caring for the patient with a disorder of the gastrointestinal system



Anatomy at a glance 1

Physiology you need to know

Neoplastic disease

Peptic ulceration

Inflammatory bowel disease

Ten top tips


ANATOMY AT A GLANCE


The main structures of the gut are shown in Figure 4.1.


image

Figure 4.1 Structural divisions of the alimentary canal.


The gut is basically a muscular tube which has a similar structure throughout its entire length consisting of four layers:


image The inner layer is the mucosa which in the stomach and small intestine contains specialized cells with secretory or absorptive functions.

image The submucosa binds the mucosa to the muscularis.

image The muscularis (muscle) layer is composed of two layers of involuntary smooth muscle from the mid oesophagus onwards, each layer arranged in a longitudinal and circular pattern. Exceptions to this general plan are the upper oseophagus, which consists of voluntary muscle to permit the conscious act of swallowing, and the stomach, which has a third oblique layer of involuntary muscle.

image The serosa, a serous membrane of connective tissue which below the diaphragm consists of the visceral peritoneum.

The gut terminates with the internal anal sphincter which connects the rectum to the anus (under involuntary control) and the external anal sphincter which connects the anus to the outside (under voluntary control).



PHYSIOLOGY YOU NEED TO KNOW


The gastrointestinal system supplies the body with the nutrients and fluids it needs to function, in an acceptable form. This is achieved by the ingestion, digestion and absorption of food and fluids.




The Stomach


Food is passed from the mouth via the oesophagus to the stomach where digestion begins. Ingested food and gastric secretions form a semi-liquid substance known as chyme which is continually churned and mixed by regular waves of muscle contraction in the stomach wall (peristalsis). The stomach mucosa contains many small gastric pits which are lined by:


image Chief cells which secrete pepsinogen. This is converted to pepsin when it comes into contact with hydrochloric acid. Pepsin is a powerful enzyme which breaks down proteins.

image Parietal cells which pump hydrogen and chloride ions into the stomach where they combine to form hydrochloric acid.

image Mucus cells which secrete mucus to protect the gastric mucosa from hydrochloric acid and pepsin.

Together with water, these components make up gastric juice which is highly acidic. This acid environment kills many bacteria and begins the breakdown of ingested food.



The Small Intestine


Digestion continues in the small intestine where enzymes (e.g. trypsin) continue the breakdown of proteins into amino acids, carbohydrates into glucose and other sugars (e.g. amylase) and fats into fatty acids and glycerol (lipase). Many of these enzymes are contained in intestinal juice secreted by cells in the intestinal wall and pancreatic juice. Bile secreted by the liver helps to emulsify fats in the duodenum, thereby facilitating fat digestion. Absorption takes place through many small projections on the small intestine wall called villi each of which in turn is covered by millions of minute hair-like projections called microvilli. The absorbed substances are carried away in the hepatic portal vein to the liver and then are made available to the rest of the body after a range of metabolic processes take place in the liver (first pass metabolism).



The Colon


The large intestine (colon) is predominantly the site of water and electrolyte absorption. A great deal of bacterial activity takes place in the colon but these bacteria are normally not pathogenic and help the body by synthesizing useful substances such as vitamin K (essential for the manufacture of prothrombin), folic acid and thiamine. Large quantities of mucus are also produced in the colon. Irritation of the colon wall increases mucus output and also causes the outpouring of water and electrolytes in an attempt to dilute and wash away the irritant. The result is diarrhoea.



NEOPLASTIC DISEASE


The gut is a major site of neoplastic disease. Three of the ten most common cancers in men affect the bowel, stomach and oesophagus whilst in women, cancer of the bowel is second only to cancer of the breast in incidence.



PATHOLOGY: Key facts



image Oesophageal cancer (p440) is increasing in frequency. It is more common in men, typically aged 50–70 and most commonly occurs in the lower third. The ability to swallow is progressively impaired and the growth spreads to involve surrounding organs such as the trachea, bronchi and stomach. The prognosis is poor with few patients surviving more than a year from diagnosis.

image Stomach cancer (p448) has the highest death rate in the age range 55–60 although the overall death rate has been falling in recent years. Predisposing factors are benign gastric ulceration, gastritis, Helicobacter pylori infection and pernicious anaemia. Gastric cancer invades adjacent organs and also spreads rapidly around the body as metastases via the lymphatic system.

image Bowel cancer (p477) most frequently occurs in the rectum. The sigmoid colon, caecum and ascending colon are the next most common sites. Cancers of the small bowel are very rare. Cancer of the colon is multifactorial in cause. A high-fat diet rich in red meat but poor in fruit and vegetables and lack of exercise are associated with an increased risk whilst some 20% of colorectal cancers have a genetic cause (e.g. familial polyposis) or a familial predisposition.


WHAT TO LOOK OUT FOR



image Oesophageal cancer Difficulty in swallowing (dysphagia) solids occurs first followed by problems with swallowing liquids. Discomfort and pain in the sub-sternal region may be accompanied by regurgitation. Loss of weight and strength develop as the person’s food intake diminishes.

image Stomach cancer has an insidious onset, gradually belching, regurgitation, nausea and vomiting develop associated with a loss of appetite, weight and strength. Blood may appear in the vomitus or colouring the stool (melaena). Pain is a relatively late sign.

image Bowel cancer usually manifests itself by a change in regular bowel habit (alternating diarrhoea or constipation) and blood in the stool which may also be steaked with mucus. The person’s overall health deteriorates as they feel tired and generally unwell, lose weight and develop anaemia. The person will often describe a feeling of incomplete evacuation when they defecate. Pain is again a late symptom and, generally speaking, the higher the cancer (e.g. in the caecum) the later the presentation as symptoms are not so apparent in the early stages.


MEDICAL MANAGEMENT


Oesophageal cancer is diagnosed by oesophagoscopy and/or barium swallow. Surgical intervention may be attempted in early cases to attempt to remove the tumour. In more advanced cases, the surgeon may only be able to introduce a feeding tube or stent to bypass the tumour and allow nutrition. Radiotherapy may also be offered to help reduce the size of the tumour.


Stomach cancer is diagnosed after endoscopy and biopsy, barium meal radiography and cytological studies of gastric juice. Computerized tomography may also be ordered to investigate the size and spread of the tumour in the abdomen and thorax. Surgery is the treatment of choice, the exact nature of the operation depending upon the tumour and its development. The lower oesophagus, omentum, spleen, pancreas or sections of the duodenum may also be involved in the surgery, depending upon the spread of the tumour. Radiotherapy and chemotherapy have so far not made any significant contribution to treatment of this cancer.


In bowel cancer, screening by faecal occult blood testing is being introduced as early detection greatly improves survival. Sigmoidoscopy or colonoscopy (and biopsy) coupled with barium enema investigations usually confirms the provisional diagnosis made from the history. Surgery to remove the tumour and a section of disease-free bowel either side is the treatment of choice. The two cut ends of the bowel are then surgically joined together (anastomosed). If the tumour is within a few centimetres of the anus, the rectum and anus are excised and a permanent colostomy formed. Radiotherapy and or chemotherapy may also be offered, particularly in advance of surgery, to shrink the size of the tumour.



PHARMACOLOGICAL FOCUS


Treatment of cancers of the gastrointestinal tract is primarily surgical, there are therefore no specific drugs unique to these disorders. Opioid analgesia is obviously important in the postoperative recovery phase for pain relief whilst in terminal illness, it plays a key role in palliative care.



PRIORITIES FOR NURSING CARE



image Oesophageal cancer patients need:
• Nutritional support such as special diet and nutritional supplements. Food must be of a consistency that they can swallow.

• Fluid balance charting and assistance and encouragement with drinking to ensure hydration.

• Oral toilet and mouth care due to risk of regurgitation.

• Privacy, support and easily accessible vomit bowl if regurgitation is a problem.

• Psychological support to deal with altered body image (serious weight loss may occur) and the knowledge that they have a terminal disease.

• Pain control postoperatively and in advanced stages of the disease when pain becomes a problem.

• Full pre- and post-operative care if surgery is being undertaken.

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Feb 3, 2017 | Posted by in NURSING | Comments Off on Caring for the patient with a disorder of the gastrointestinal system

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