Gastroenterology

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4 Gastroenterology

Vomiting

Vomiting centres are located on the lateral reticular formation of the medulla and are stimulated by chemoreceptors trigger zones on the floor of the 4th ventricle and also by vagal afferents from the GI tract.

Causes of vomiting are shown in Table 4.1.

Table 4.1 Causes of vomiting

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Case history

A 70-year-old man was admitted with a 2-week history of repeated vomiting. He had lost more than 6 kg in weight. He had recently developed colicky abdominal pain and constipation without passage of wind.

On examination, his abdomen was distended and he was tender in the epigastrium.

You call for surgical advice. The surgeon, in addition to your findings, notes that there are increased bowel sounds. The patient’s hernial orifices and rectal examination show no abnormality.

Remember

Non-gastrointestinal causes are possible: a full examination is therefore necessary. Note: look at the fundi for papilloedema.

Investigations

• Haematological:

– FBC, ESR, CRP

• Radiological:

– Abdominal X-ray
– Chest X-ray

• Biochemical:

– Electrolytes
– Urea/creatinine/eGFR
– LFTs
– Calcium
– Amylase

• Chest X-ray (CXR). Normal. Look for evidence of air under the diaphragm (perforation), signs of pneumonia, hilar mass (tumour).

• Abdominal X-ray (AXR). Normal. With a history of this length, a normal X-ray would suggest that large or small bowel obstruction is unlikely. High obstruction in the gastrointestinal (GI) tract, i.e. in the oesophagus or stomach, is possible. Investigate for non-GI causes (metabolic, neurological – exclude brainstem lesion), occasionally severe depression.

• Abnormal. Might show evidence of small or large bowel obstruction or gastric distension.

In this patient, the AXR showed small bowel obstruction (Fig. 4.1). The differential diagnosis is shown in the Information box.

image

Figure 4.1 Small bowel obstruction, showing dilated loops of small bowel.

Information

Small intestinal obstruction: differential diagnosis:

• Adhesions (80% in adults)

• Hernia

• Crohn’s disease

• Intussusception

• Obstruction due to extrinsic involvement by cancer

Management

The ultimate goal is to relieve obstruction. In the interim:

• Infuse glucose/saline to maintain electrolyte balance (with additional K+ 20 mmol per litre).

• Insert nasogastric tube (on continuous drainage).

• Contact surgeons, await instruction as to further investigations (such as CT scan to localise obstructive lesion).

Progress.

At operation, a carcinoma of the ascending colon was found and resected.

Hiccups

Hiccups are due to involuntary diaphragmatic contractions with closure of the glottis. They are very common and usually not sinister, even if persistent.

Case history

You are called by the surgical SHO because he is concerned that a 70-year-old man has had continuous hiccups for 48 h, a fever, malaise and right hypochondrial pain. Ten days ago he had been admitted with intestinal obstruction (see case above) and a laparotomy for a carcinoma of the ascending colon had been performed. This is a classic situation for a subphrenic abscess occurring post-surgery in an elderly person.

How would you investigate?

Check Hb, WBC and liver biochemistry. An urgent ultrasound was performed and confirmed the diagnosis of a subphrenic abscess. Blood cultures were taken as he was febrile.

Treatment and prognosis of the abscess

He had drainage under ultrasound control and antibiotics were started. The bacteria causing abscesses are usually Bacteroides spp. and/or E. coli and he was therefore treated with a cephalosporin and metronidazole. His hiccups were controlled with chlorpromazine 50 mg or diazepam 5 mg as necessary.

Other causes of hiccups

• Metabolic, e.g. uraemia

• Neurological, e.g. brainstem tumour

• Other abdominal pathology

• No pathological cause.

Weight loss

Weight loss is often a perceived symptom by patients but does need to be verified. It is a general symptom, which can reflect disease in any part of the body.

Always make sure that the patient has a sufficient calorie intake for his/her requirements, bearing in mind the amount of exercise taken. In a young female, think of anorexia nervosa.

Reduced calorie intake can be due to intentional dieting but can also be a symptom of generalised disease due to anorexia.

Case history

A 40-year-old man has been admitted with a fever, tremor and 10 kg weight loss. He has previously been counselled for alcohol misuse.

What should you do?

You need to consider a number of diagnoses and this might be helped by additional history and examination:

• Hyperthyroidism: check for symptoms and signs of hyperthyroidism (see p. 434).

• Alcoholic liver disease (see p. 70).

• Malnutrition: check by asking the patient’s family. Perhaps there is a psychiatric history?

• Underlying cancer, particularly lung, bowel and pancreas.

• Biochemical investigations: should help determine underlying metabolic or renal disease.

• Malabsorption: often causes anorexia, which contributes to weight loss.

This patient had no major signs of chronic liver disease but did admit to recurrent episodes of upper abdominal pain radiating through to his back. These tended to occur on Monday, following his weekend binges. This suggests pancreatic disease resulting from his heavy alcohol intake.

What initial investigations are appropriate?

• FBC, LFTs, calcium, blood alcohol

• Plain X-ray of the abdomen for pancreatic calcification

• Abdominal ultrasound to assess the pancreas for cysts and potential masses.

This patient was admitted in a malnourished, hyperdynamic state due to acute alcohol withdrawal (see p. 72). Treat this initially and further investigate the pancreas later.

Further investigations

• CT scan of the pancreas:

• MRCP: this is non-invasive and of value in assessment of the pancreas and biliary tree

• ERCP to delineate the biliary and pancreatic ducts (if MRCP is unavailable)

• Endoscopic ultrasound: can help define pancreatic cysts and masses

Progress.

This man was treated initially with benzodiazepine and IV thiamine (p. 527) and made a good recovery from his acute withdrawal state. Further investigations showed chronic pancreatitis; he was referred to the Gastroenterology Clinic.

Dysphagia

Dysphagia is difficulty in swallowing. It is an immediate, obstructive sensation during the passage of liquid or solid through the pharynx or oesophagus.

Case history

A 55-year-old patient has been referred urgently because of acute dysphagia. She gave a history of reflux for years and increasing dysphagia for 6 months. She had been eating an orange, which became lodged in her gullet and all efforts to dislodge it were unsuccessful. The underlying diagnosis is likely to be food bolus obstruction on an already present oesophageal stricture.

What should you do?

Refer for an urgent endoscopy. The endoscopy findings were of a stricture in the mid-oesophagus with no obvious malignant lesion. Biopsies were taken and the stricture dilated.

Remember

Submucosal cancer can look like a benign lesion.

Unfortunately, this woman developed severe chest pain immediately after the dilatation and surgical emphysema could be felt in her neck. Clinically, an oesophageal tear is suspected.

A CXR with a water soluble contrast agent orally, confirms an oesophageal rupture.

Diagnosis.

The underlying cause is more likely to be oesophageal cancer because careful dilatation of benign lesions rarely causes a tear.

Initial management

• Nil by mouth

• IV line for fluids

• Antibiotic prophylaxis

• Surgical referral.

Small tears in a peptic stricture can resolve in a few days on conservative management. Large tears generally need surgery in a dedicated thoracic unit. Endoscopic stenting is used initially for tears in malignant lesions but again surgery may be required.

Biopsies later confirmed a squamous carcinoma.

Management will include assessment for surgery with:

• Blood count, liver biochemistry

• CXR

• ECG

• Respiratory function tests

• Abdominal US, CT scan to assess operability

• Endoscopic ultrasound is an accurate way of staging lesion and any local lymph nodes

• PET scan to look for distant metastases.

Discussion should take place at an MDT to decide on the patient’s treatment.

As investigations showed no distant metastases, surgery with neo-adjuvant (preoperative) and adjuvant (postoperative) chemoradiation treatment was given.

Constipation

This is the infrequent passage of stools, < 3 per week + straining and the passage of hard stools.

Case history

Your house officer asks you what she should prescribe for an elderly man who hasn’t opened his bowels for 5 days. The patient, who was previously well and active, had been admitted a week ago with a chest infection. Rectal examination revealed a loaded colon with no local lesion.

Should this patient be investigated?

Not initially because it seems likely that constipation is due to immobility. A barium enema may be necessary if there is no improvement.

Treatment

• Initially, the patient will require a laxative to ‘get things moving’. Glycerol suppositories are useful. Oral magnesium sulphate, an osmotic purgative, is effective and cheaper than the more usually prescribed osmotic laxative lactulose.

• Do not use stimulant laxatives.

• Stop ‘constipating’ drugs if possible.

• Faecal impaction might require digital extraction followed by small-volume phosphate enemas.

• Advise the patient regarding high-fibre diets and fluid intake.

Information

Causes of constipation:

• Simple/idiopathic

• Intestinal obstruction

• Colonic disease, e.g. carcinoma

• Painful anal conditions

• Drugs, e.g. codeine, iron, verapamil, tricyclic anti-depressants, opiates

• Hypothyroidism, hypercalcaemia

• Depression

• Immobility

Diarrhoea

Increased frequency of defecation can, even in a previously fit patient, produce dehydration and severe electrolyte depletion. Diarrhoea can also be a recurrent problem in patients with established gastrointestinal disease.

What should you do in a case of diarrhoea presenting in A&E?

In the history, ascertain whether the patient has eaten suspect food or travelled overseas. Check for drug history, e.g. antibiotics. Ask about accompanying symptoms, e.g. abdominal pain, weight loss. It is essential to:

• Establish history of onset.

• Determine frequency, consistency, content of stool, presence of blood.

• Determine the state of hydration and electrolyte balance.

• Send stool for culture, parasites (ova or cysts) and C. difficile toxin (if the patient has previously been hospitalised or been on antibiotics).

• Perform a rectal examination; sigmoidoscopy (if bloody diarrhoea) should be done by the gastroenterology team.

• Do blood cultures in severe cases with a temperature.

• Do a plain abdominal X-ray.

Information

Likely pathogens causing diarrhoea

Bacteria (50%):

• E. coli

• Campylobacter spp.

• Salmonella spp.

• Shigella spp.

Viruses (1% but seldom produce severe diarrhoea in adults):

• Rotavirus

• Noravirus

Protozoa:

• Giardia

• Entamoeba histolytica

• Cryptosporidium

Helminths (e.g. Strongyloides):

Some cases have no pathogens or multiple pathogens found (this occurs in 20–50% of cases).

Management

This will depend on the case scenario (see below) but most diarrhoeal illnesses are self-limiting and short lived; 1–10% might persist for a month. Identification of the pathogen will determine specific therapy (see Chapter 1).

Case history (1)

A 24-year-old returned from travelling for 3 months, during which he passed through several countries. He was fairly well on his return but after 3 days he developed severe diarrhoea which has now been present for 2 weeks.

On admission to MAU he is dehydrated and has lost over 5 kg in weight.

What immediate action would you take?

• FBC, U&Es, LFTs.

• Send stools for ova, cysts and culture.

• Rehydration with oral glucose/electrolyte solutions initially. IV fluids are usually not necessary.

• Vomiting might need to be treated with an anti-emetic (metoclopramide 10 mg × 3/day).

Diagnosis

This is not acute diarrhoea due to a viral/bacterial cause as the patient did not have diarrhoea when he returned to the UK. Viral/bacterial diarrhoea usually starts in the country where the infection occurred and generally clears up within 7 days. Possible causes are shown in the Information box.

Information

Causes of non-acute diarrhoea in a returning traveller:

• Giardiasis

• Cryptosporidiosis

• Amoebiasis

• Tropical sprue (SE Asia, Caribbean)

• Schistosomiasis

• Strongyloidiasis

Stool samples showed no abnormal findings.

Progress.

Giardiasis is very likely in this patient and treatment with metronidazole 2 g a day for 3 successive days was given, with dramatic improvement.

Case history (2)

A 30-year-old, white, Caucasian, female patient presented with a 2-week history of passing six to ten motions a day. The stools were loose and contained blood. She felt tired and had lost about 5 kg in weight.

On admission to MAU she was not dehydrated but had a fever and was very lethargic.

What is the differential diagnosis?

• Infective diarrhoea. Send specimens for microbiological testing.

• First presentation of inflammatory bowel disease (most likely in this woman).

Inflammatory bowel disease (IBD)

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