Gastrointestinal and nutritional disorders

12 Gastrointestinal and nutritional disorders


Diseases of the GI tract are a major cause of morbidity and mortality. Approximately 10% of all GP consultations in the UK are for indigestion, and 1 in 14 is for diarrhoea. Infective diarrhoea and malabsorption are responsible for much ill health and many deaths in the developing world.



PRESENTING PROBLEMS




DYSPEPSIA


Dyspepsia (‘indigestion’) may arise from causes within or outside the gut (Box 12.1). Heartburn and other ‘reflux’ symptoms are separate and are considered elsewhere. Although symptoms correlate poorly with diagnosis, careful history may reveal classical symptoms of peptic ulcer, ‘alarm’ features requiring urgent investigation (Box 12.2) or symptoms of other disorders. Dyspepsia affects up to 80% of the population at some time, often with no abnormality on investigation, especially in younger patients.








CLINICAL EXAMINATION OF THE GASTROINTESTINAL TRACT






GI BLEEDING



ACUTE UPPER GI HAEMORRHAGE


This is the most common GI emergency, accounting for 50–120 hospital admissions per 100 000 each year in the UK.


Haematemesis may be red with clots when bleeding is profuse, or black (‘coffee grounds’) when less severe. Syncope may occur with rapid bleeding. Anaemia suggests chronic bleeding. Melaena is the passage of black, tarry stools containing altered blood. This is usually due to upper GI bleeding, although the ascending colon is occasionally responsible. Severe acute upper GI bleeding occasionally causes maroon or bright red stool. Causes of acute upper GI haemorrhage are shown in Box 12.3.




Management


I.V. access: Should be secured with a large-bore cannula.


Clinical assessment: Should be made for circulatory status (tachycardia, hypotension and oliguria indicating severe bleeding), liver disease (jaundice, cutaneous stigmata, hepatosplenomegaly and ascites) and comorbidity (cardiorespiratory, cerebrovascular or renal disease, which increases the hazards of endoscopy and surgery).


Blood tests: FBC (slow bleeding causes anaemia; haemoglobin may be normal after sudden, major bleeding); cross-matching of at least 2 U of blood; U&Es (shock may cause renal failure; the urea also rises as the luminal blood is digested); LFTs and prothrombin time, if there is clinical suggestion of liver disease or in anticoagulated patients.


Resuscitation: Oxygen should be given to all patients in shock. I.V. crystalloid or colloid infusion restores blood pressure. Normal saline should be avoided in liver disease because it can cause ascites. Blood transfusion should be given if there is shock or the haemoglobin is <100 g/litre. CVP monitoring helps to reveal rebleeding and guide fluid replacement.


Endoscopy: After resuscitation, this will reveal a diagnosis in 80% of cases. Patients with spurting haemorrhage or a visible vessel can be treated by thermal probe, adrenaline (epinephrine) injection or metal clips. This may stop bleeding and, combined with i.v. proton pump inhibitor (PPI) therapy, prevent rebleeding, thus avoiding surgery.


Monitoring: Hourly pulse, BP and urine output.


Surgery: Indicated when endoscopic haemostasis fails to stop the bleeding, or rebleeding occurs once in an elderly or frail patient/twice in younger, fitter patients. Following successful surgery for ulcer bleeding, all patients should be treated with H. pylori eradication therapy if positive and should avoid NSAIDs.








WEIGHT LOSS


Unplanned weight loss of >3 kg over 6 mths is significant. Previous weight records may be valuable. Pathological weight loss can be due to psychiatric illness, systemic disease, GI causes or advanced disease of any specific organ system.




History and examination


‘Physiological’ weight loss: Should be obvious from the history but may be more difficult to determine in older patients when nutritional history may be unreliable; a dietitian’s opinion is often valuable.


Psychiatric illness: Features of anorexia nervosa, bulimia and affective disorders may only be apparent after formal psychiatric input. Alcoholic patients lose weight through self-neglect and poor diet.


Systemic diseases: Chronic infections lead to weight loss, and a history of foreign travel, fever, night sweats, rigors, productive cough and dysuria must be sought. Sensitive questions regarding lifestyle (promiscuous sexual activity and drug misuse) may suggest HIV infection. Weight loss is a late feature of disseminated malignancy (carcinoma, lymphoma or other haematological disorders), which may be revealed on examination.


GI disease: Dysphagia and gastric outflow obstruction cause defective intake. Malignancy may cause weight loss by mechanical obstruction, anorexia or systemic effects. Malabsorption from pancreas or small bowel causes profound weight loss and nutritional deficiencies. Crohn’s disease and ulcerative colitis cause anorexia, fear of eating, and loss of protein, blood and nutrients from the gut.


Specific diseases of any major organ system: Endocrine disease, including diabetes mellitus, Addison’s disease and thyrotoxicosis, may cause weight loss. In patients with disabling end-stage respiratory, cardiac or rheumatological diseases, weight loss occurs from a combination of anorexia, physical disability and the systemic effects of their conditions, often compounded by drug effects (e.g. digoxin) which may cause nausea, dyspepsia, constipation or depression.





ABDOMINAL PAIN


Abdominal pain may be:







THE ACUTE ABDOMEN


This accounts for ∼50% of all urgent admissions to general surgical units. It is a consequence of one or more pathological processes:


Inflammation (e.g. appendicitis, pancreatitis, diverticulitis): Diffuse pain develops gradually, over hours. If the parietal peritoneum is involved, pain becomes localised. Movement exacerbates it; rigidity and guarding occur.


Perforation (e.g. peptic ulcer, ovarian cyst, diverticular disease): Pain starts abruptly, is severe and leads to generalised peritonitis.


Obstruction (intestinal, biliary or ureteric): Pain is colicky, with spasms causing the patient to writhe around. If it does not disappear between spasms, this suggests complicating inflammation.


If there are signs of peritonitis (i.e. guarding and rebound tenderness with rigidity), adequate resuscitation is needed. In other circumstances further investigations are required:















DISORDERS OF NUTRITION




MALNUTRITION



STARVATION AND FAMINE


There remain regions of the world, particularly in Africa, where the prevalence of BMI <18.5 in adults remains as high as 20%. In adults, the predominant form of protein–energy malnutrition is undernutrition, i.e. a sustained negative energy (calorie) balance.


Decreased energy intake: Causes include:







Increased energy expenditure: Causes include:










MALNUTRITION IN HOSPITAL


One-third of hospital patients in the UK (particularly the elderly) are affected by moderate or severe malnutrition on admission. Once in hospital, many lose weight due to poor appetite, concurrent illness and being kept ‘nil by mouth’ for investigations. Malnutrition leads to impaired immunity and muscle weakness, and to increased morbidity, mortality and length of stay.



Nutritional support of the hospital patient


Normal diet: Inadequate intake may be due to unpalatability of food, cultural and religious factors restricting diet, or simple problems such as difficulty with hand dexterity (arthritis, stroke) or immobility in bed. Patients at risk of malnutrition should have food intake charted.


Dietary supplements: If a patient is unable to achieve sufficient nutritional intake from normal diet alone, then liquid dietary supplements with high energy and protein content should be used.


Enteral tube feeding: Patients who cannot swallow may require artificial nutritional support. The enteral route should be used if possible, as this preserves the integrity of the mucosal barrier, prevents bacteraemia and, in intensive care patients, reduces the risk of multi-organ failure.





Parenteral nutrition: IV feeding is expensive, carries higher risks of complications and should only be used when enteral feeding is impossible. Less than 1wk of parenteral feeding confers little benefit. There are a number of possible routes:







ANOREXIA NERVOSA


Anorexia nervosa is a well-defined eating disorder, although a much higher prevalence of abnormal eating behaviour in the population does not meet the diagnostic criteria. There is marked weight loss, arising from food avoidance, in combination with bingeing, purging, excessive exercise, or the use of diuretics and laxatives. Despite their emaciation, patients feel overweight due to body image disturbance. Downy hair (lanugo) develops on the back, forearms and cheeks. Extreme starvation is associated with a range of pathophysiological changes, such as cardiac arrhythmias (prolonged QT and ventricular tachycardia), anaemia and osteoporosis. The condition usually emerges in adolescence, and 90% of cases are female.


Diagnostic criteria are:






Differential diagnosis includes:









OBESITY


Obesity is a pandemic with potentially disastrous consequences for health. More than 20% of adults in the UK and more than 30% in USA are obese. The prevalence of obesity is increasing.


The pandemic reflects changes in both energy intake and expenditure. The estimated average global daily supply of food energy per person increased from ∼2350kcal in the 1960s to ∼2800kcal in the 1990s. Portion sizes, particularly of sugary drinks and high-fat snacks, have increased. Corresponding changes in energy expenditure are important; obesity is correlated positively with hours spent watching television, and inversely with physical activity.


Although obese people were ridiculed in the past when they bemoaned their inability to control their weight, it is likely that susceptibility does vary between individuals. Twin studies confirm a genetic pattern of inheritance, suggesting a polygenic disorder. In a few cases, specific causal factors can be identified, such as hypothyroidism, Cushing’s syndrome or insulinoma. Drugs implicated include: tricyclic antidepressants, sulphonylureas, sodium valproate and β-blockers.






Management


The health risks of obesity are largely reversible. Interventions which reduce weight in studies in obese patients have also been shown to ameliorate cardiovascular risk factors. Lifestyle advice which lowers body weight and increases physical exercise reduces the incidence of type 2 diabetes.


Most patients seeking assistance will have attempted weight loss previously, sometimes repeatedly. An empathetic explanation of energy balance, recognising that some individuals are more susceptible to obesity, is important. Appropriate weight loss goals (e.g. 10% of body weight) should be agreed.


Lifestyle advice: All patients should be advised to maximise their physical activity by incorporating it into the daily routine (e.g. walking rather than driving to work). Changes in eating behaviour (including portion size control, avoidance of snacking, regular meals to encourage satiety, and use of artificial sweeteners) should be discussed.


Weight loss diets: In overweight people, the lifestyle advice given above may gradually succeed. In obese patients, more active intervention is usually required. Weight loss diets require a reduction in daily total energy intake of ∼2.5MJ (600kcal) from the patient’s normal consumption. The goal is to lose ∼0.5kg/week. Patient compliance is the major determinant of success. In some patients more rapid weight loss is required, e.g. in preparation for surgery. There is no role for starvation diets, which carry a risk of sudden death from heart disease. Very low calorie diets produce weight loss of 1.5–2.5kg/week, but require the supervision of a physician and nutritionist.


Drugs: Drug therapy is usually reserved for obese patients with a high risk of complications. Patients who continue to take anti-obesity drugs tend to regain weight with time. This has led to the recommendation that anti-obesity drugs are used short-term to maximise the weight loss in patients who are demonstrating their adherence to a low calorie diet by current weight loss.




Surgery: Surgery to reduce the size of the stomach is the most effective long-term treatment for obesity. It should be contemplated in patients with a very high risk of developing the complications of obesity, in whom dietary and drug therapy has been ineffective. The mechanism of weight loss may not relate to limiting the stomach capacity per se, but rather in disrupting the release of ghrelin from the stomach, which signals hunger in the hypothalamus. Mortality is low in experienced centres but post-operative complications are common.



DISEASES OF THE MOUTH AND SALIVARY GLANDS


Aphthous ulceration: Common, superficial, painful and idiopathic. In severe cases other causes, such as infection, drug reaction or Behçet’s syndrome, must be considered. Topical triamcinolone in Orabase or choline salicylate gel can aid healing.


Squamous carcinoma of the oral cavity: Common world-wide and increasing in the UK. Mortality is ∼50%, largely as a result of late diagnosis. Poor diet, alcohol excess, smoking or tobacco chewing, or chewing areca nuts wrapped in betel leaves (‘betel nuts’) are the main risk factors. Suspicious lesions should be biopsied if treatment for local trauma or infection fails to produce improvement after 2 wks. Treatment is by resection, radiotherapy or both.


Vincent’s angina: Deep, sloughing gum ulcers, caused by invasion of the mucous membranes by organisms such as Borrelia vincentii. Poor oral hygiene, malnutrition, debility and AIDS predispose. Symptoms include halitosis and fever, and treatment with hydrogen peroxide mouthwashes and broad-spectrum antibiotics is indicated.


Candida albicans: A normal mouth commensal which proliferates to cause thrush in babies, patients receiving corticosteroids, antibiotic or cytotoxic therapy, people with diabetes and the immunosuppressed. White patches are seen on the tongue and buccal mucosa. Dysphagia suggests pharyngeal and oesophageal candidiasis. A clinical diagnosis is sufficient to instigate therapy, using nystatin or amphotericin suspensions or lozenges.


Parotitis: Due to viral or bacterial infection. Mumps causes a self-limiting acute parotitis. Bacterial parotitis usually occurs as a complication of major surgery and can be avoided by good post-operative care. Broad-spectrum antibiotics are required, whilst surgical drainage is necessary if abscesses are present.



DISEASES OF THE OESOPHAGUS



GASTRO-OESOPHAGEAL REFLUX DISEASE (GORD)


Gastro-oesophageal reflux resulting in heartburn affects ∼30% of the general population.


GORD develops when the oesophageal mucosa is exposed to gastric contents for prolonged periods, resulting in symptoms and, in a proportion of cases, oesophagitis. Reflux may occur if there is reduced oesophageal sphincter tone or frequent inappropriate sphincter relaxation. Herniation of the stomach through the diaphragm (hiatus hernia) occurs in 30% of the population >50 and is often asymptomatic. It causes reflux because of loss of the oblique angle between the cardia and oesophagus. Almost all patients who develop oesophagitis, Barrett’s oesophagus or peptic strictures have a hiatus hernia. Defective oesophageal peristaltic activity is common in patients with oesophagitis, and persists after oesophagitis has been healed by acid-suppressing drugs.


Gastric acid is the most important oesophageal irritant and there is a close relationship between acid exposure time and symptoms. Gastric emptying is delayed in patients with GORD. Increased intra-abdominal pressure due to pregnancy and obesity may contribute. Weight loss may improve symptoms. Dietary fat, chocolate, alcohol and coffee relax the lower oesophageal sphincter and may provoke symptoms.





Complications


Oesophagitis: Features a range of endoscopic findings, from mild redness to severe, bleeding ulceration with stricture formation, with a poor correlation between symptoms and appearances. A normal endoscopy and normal histology do not exclude significant reflux disease.


Barrett’s oesophagus (‘columnar lined oesophagus’, CLO): A premalignant condition in which the squamous lining of the lower oesophagus is replaced by columnar mucosa with areas of metaplasia. It occurs in response to chronic reflux and is seen in 10% of endoscopies for reflux. The true prevalence may be up to 20 times greater, as it is often asymptomatic or first discovered when the patient develops oesophageal cancer. CLO carries a lifetime risk of oesophageal adenocarcinoma of ∼10%. The absolute risk is low and >95% of patients with CLO die of causes other than oesophageal cancer. Prevalence is increasing, especially in white men aged >50. It is weakly associated with smoking but not alcohol. Duodenogastro-oesophageal reflux, containing bile, pancreatic enzymes and pepsin in addition to acid, may be important.


Diagnosis requires multiple biopsies to detect intestinal metaplasia and/or dysplasia.


Neither acid suppression nor antireflux surgery stops progression of CLO, and treatment is only indicated for symptoms of reflux or complications such as stricture. Endoscopic ablation or photodynamic therapy can induce regression but islands of glandular mucosa remain and cancer risk is not eliminated. Regular endoscopic surveillance is controversial; it can detect dysplasia and early malignancy but, because most CLO is undetected until cancer develops, will not reduce overall oesophageal cancer mortality.


Oesophagectomy is widely recommended for those with high-grade dysplasia (HGD), as the resected specimen harbours cancer in up to 40%. Close follow-up with biopsies every 3 mths is an alternative for those with HGD.


Iron deficiency anaemia: Occurs as a consequence of chronic blood loss from oesophagitis. Many such patients have bleeding from erosions in a hiatus hernia. Nevertheless, hiatus hernia is very common and other causes of blood loss, particularly colorectal cancer, must be considered even when endoscopy reveals oesophagitis and a hiatus hernia.


Benign oesophageal stricture: Develops as a consequence of longstanding oesophagitis, usually in elderly patients presenting with dysphagia for solids. A history of heartburn is common but not invariable in the elderly. Diagnosis is by endoscopy, when biopsies can be taken to exclude malignancy. Endoscopic balloon dilatation or bouginage is helpful, followed by long-term therapy with a PPI to reduce the risk of recurrence. Dentition should be checked and the patient advised to chew food thoroughly.


Gastric volvulus: Occasionally a massive intrathoracic hiatus hernia twists upon itself (gastric volvulus), causing complete obstruction, severe chest pain, vomiting and dysphagia. The diagnosis is made by CXR and barium swallow. Most resolve spontaneously but recur and surgery is usually advised.






MOTILITY DISORDERS




ACHALASIA OF THE OESOPHAGUS


Achalasia is characterised by a hypertonic lower oesophageal sphincter which fails to relax during swallowing and failure of propagated oesophageal contraction, with progressive dilatation. The cause is unknown, although failure of the local nerve supply is implicated. Chagas disease (infestation with Trypanosoma cruzi) is endemic in South America and causes an indistinguishable clinical syndrome (p. 112).






TUMOURS OF THE OESOPHAGUS



CARCINOMA OF THE OESOPHAGUS


Almost all are adenocarcinoma or squamous cancers. Small-cell cancer is a rare third type.


Squamous cancer: Rare in the West (approx. 4 : 100 000) but common in Iran, parts of Africa and China (200 : 100 000). Squamous cancer can arise anywhere in the oesophagus but almost all tumours above the lower third of the oesophagus are squamous.


Adenocarcinoma: Arises in the lower third of the oesophagus from Barrett’s oesophagus or from the cardia of the stomach. Incidence is increasing in the UK (approx. 5 : 100 000).






DISEASES OF THE STOMACH AND DUODENUM


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Apr 3, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Gastrointestinal and nutritional disorders

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