The gastrointestinal system

Chapter 6 The gastrointestinal system





Gastroenterologists and gastrointestinal surgeons concern themselves with the entire length of the gut, the liver, the exocrine pancreas and the peripheral effects of alimentary disease.



The gastrointestinal history



Presenting symptoms (Table 6.1)



Abdominal pain


There are many causes of abdominal pain, and careful history taking will often lead to the correct diagnosis. The following should be considered.


TABLE 6.1 Gastrointestinal history







Major symptoms





















Patterns of pain











Heartburn and acid regurgitation


Heartburn refers to the presence of a burning pain or discomfort in the retrosternal area. Typically, this sensation travels up towards the throat and occurs after meals or is aggravated by bending, stooping or lying supine. Antacids usually relieve the pain, at least transiently. This symptom is due to regurgitation of stomach contents into the oesophagus. Usually these contents are acidic, although occasionally alkaline reflux can induce similar problems. Associated with gastro-oesophageal reflux may be acid regurgitation, in which the patient experiences a sour or bitter-tasting fluid coming up into the mouth. This symptom strongly suggests that reflux is occurring. Some patients complain of a cough that troubles them when they lie down. In patients with gastro



oesophageal reflux disease, the lower oesophageal sphincter muscle relaxes inappropriately. Reflux symptoms may be aggravated by alcohol, chocolate, caffeine, a fatty meal, theophylline, calcium channel blockers and anticholinergic drugs, as these lower the oesophageal sphincter pressure.


Waterbrash refers to excessive secretion of saliva into the mouth and should not be confused with regurgitation; it may occur, uncommonly, in patients with peptic ulcer disease or oesophagitis.



Dysphagia


Dysphagia is difficulty in swallowing. Such difficulty may occur with solids or liquids. The causes of dysphagia are listed in Table 6.2. If a patient complains of difficulty swallowing, it is important to differentiate painful swallowing from actual difficulty.1 Painful swallowing is termed odynophagia and occurs with any severe inflammatory process involving the oesophagus. Causes include infectious oesophagitis (e.g. Candida, herpes simplex), peptic ulceration of the


TABLE 6.2 Causes of dysphagia









Mechanical obstruction


















oesophagus, caustic damage to the oesophagus or oesophageal perforation.


If the patient complains of difficulty initiating swallowing, fluid regurgitating into the nose or choking on trying to swallow, this suggests that the cause of the dysphagia is in the pharynx (pharyngeal dysphagia). Causes of pharyngeal dysphagia can include neurological disease (e.g. motor neurone disease, resulting in bulbar or pseudobulbar palsy).


If the patient complains of food sticking in the oesophagus, it is important to consider a number of anatomical causes of oesophageal blockage.1 Ask the patient to point to the site where the solids stick. If there is a mechanical obstruction at the lower end of the oesophagus, most often the patient will localise the dysphagia to the lower retrosternal area. However, obstruction higher in the oesophagus may be felt anywhere in the retrosternal area. If heartburn is also present, for example, this suggests that gastro-oesophageal reflux with or without stricture formation may be the cause of the dysphagia. The actual course of the dysphagia is also a very important part of the history to obtain. If the patient states that the dysphagia is intermittent or is present only with the first few swallows of food, this suggests either a lower oesophageal ring or oesophageal spasm. However, if the patient complains of progressive difficulty swallowing, this suggests a stricture, carcinoma or achalasia. If the patient states that both solids and liquids stick, then a motor disorder of the oesophagus is more likely, such as achalasia or diffuse oesophageal spasm.



Diarrhoea


The symptom diarrhoea can be defined in a number of different ways. Patients may complain of frequent stools (more than three per day being abnormal) or they may complain of a change in the consistency of the stools, which have become loose or watery. There are a large number of possible causes of diarrhoea.


Some patients pass small amounts of formed stool more than three times a day because of an increased desire to defecate. The stools are not loose and stool volume is not increased. This is not true diarrhoea. It can occur because of local rectal pathology, incomplete rectal emptying, or because of a psychological disturbance that leads



to an increased interest in defaecation.


When a history of diarrhoea is obtained, it is also important to determine if this has occurred acutely or whether it is a chronic problem. Acute diarrhoea is more likely to be infectious in nature, while chronic diarrhoea has a large number of causes.


Clinically, diarrhoea can be divided into a number of different groups based on the likely disturbance of physiology.2



2. Osmotic diarrhoea is characterised by its

disappearance with fasting and by large-volume stools related to the ingestion of food. Osmotic diarrhoea occurs due to excessive solute drag; causes include lactose intolerance (disaccharidase deficiency), magnesium antacids or gastric surgery.






Constipation


It is important to determine what patients mean if they say they are constipated.3 Constipation is a common symptom and can refer to the passage of infrequent stools (fewer than three times per week), hard stools or stools that are difficult to evacuate. This symptom may occur acutely or may be a chronic problem. In many patients, chronic constipation arises because of habitual neglect of the impulse to defecate, leading to the accumulation of large, dry faecal masses. With constant rectal distension from faeces, the patient may grow less aware of rectal fullness, leading to chronic constipation. Constipation may arise from ingestion of drugs (e.g. codeine, antidepressants and aluminium or calcium antacids), and with various metabolic or endocrine diseases (e.g. hypothyroidism, hypercalcaemia, diabetes mellitus, phaeochromocytoma, porphyria, hypokalaemia) and neurological disorders (e.g. aganglionosis, Hirschsprung’sb disease, autonomic neuropathy, spinal cord injury, multiple sclerosis). Constipation can also arise after partial colonic obstruction from carcinoma; it is, therefore, very important to determine whether there has been a recent change in bowel habit, as this may indicate development of a malignancy. Patients with very severe constipation in the absence of structural disease may be found on a transit study to have slow colonic transit; such slow-transit constipation is most common in young women.


Constipation is common in the later stages of pregnancy.


Difficulty with evacuation of faeces may occur with disorders of the pelvic floor muscles or nerves, or anorectal disease (e.g. fissure, or stricture). Patients with this problem may complain of straining, a feeling of anal blockage or even the need to self-digitate to perform manual evacuation of faeces.


A chronic but erratic disturbance in defaecation (typically alternating constipation and diarrhoea) associated with abdominal pain, in the absence of any structural or biochemical abnormality, is very common; such patients are classified as having the irritable bowel syndrome.4 Patients who report abdominal pain plus two or more of the following symptoms—abdominal pain relieved by defaecation, looser or more frequent stools with the onset of abdominal pain, passage of mucus per rectum, a feeling of incomplete emptying of the rectum following defaecation and visible abdominal distension—are more likely to have the irritable bowel syndrome than organic disease.




Bleeding


Patients may present with the problem of haematemesis (vomiting blood), melaena (passage of jet-black stools) or haematochezia (passage of bright-red blood per rectum). Sometimes patients may present because routine testing for occult blood in the stools is positive (page 183). It is important to ensure that if vomiting of blood is reported, this is not the result of bleeding from a tooth socket or the nose, or coughing up of blood.


Haematemesis indicates that the site of the bleeding is proximal to or at the duodenum. Ask about symptoms of peptic ulceration; haematemesis is commonly due to bleeding chronic peptic ulceration, particularly from a duodenal ulcer. Acute peptic ulcers often bleed without abdominal pain. A Mallory-Weiss tear usually occurs with repeated vomiting; typically the patient reports first the vomiting of clear gastric contents and then the vomiting of blood. Less-common causes of upper gastrointestinal bleeding are presented in Table 6.3.


TABLE 6.3 Causes of acute gastrointestinal bleeding











Upper gastrointestinal tract
Less common
3. Mallory-Weiss* syndrome (tear at the gastro-oesophageal junction)




7. Dieulafoy’s ulcer (single defect that involves an ectatic submucosal artery)









Lower gastrointestinal tract
Less common



8. Meckel’s# diverticulum




CRST = calcinosis, Raynaud’s phenomenon, sclerodactyly and telangiectasia.


* George Kenneth Mallory (b. 1900), professor of pathology, Boston, and Soma Weiss (1898–1942), professor of medicine, Boston City Hospital described this syndrome in 1929.


Georges Dieulafoy (1839–1911), Paris physician.


Edvard Ehlers (1863–1937), German dermatologist, described the syndrome in 1901, and Henri Alexandre Danlos (1844–1912), French dermatologist, described the syndrome in 1908.


§ Pierre Ménétrier (1859–1935), French physician.


# Johann Friedrich Meckel the younger (1781–1833), Professor of Surgery and Anatomy at Halle. His father and grandfather were also professors of anatomy.


Haemorrhoids and local anorectal diseases such as fissures will commonly present with passing small amounts of bright-red blood per rectum. The blood is normally not mixed in the stools but is on the toilet paper, on top of the stools or in the toilet bowl. Melaena usually results from bleeding




from the upper gastrointestinal tract, although right-sided colonic and small bowel lesions can occasionally be responsible. Massive rectal bleeding can occur from the distal colon or rectum, or from a major bleeding site higher in the gastrointestinal tract. With substantial lower gastrointestinal tract bleeding, it is important to consider the presence of angiodysplasia or diverticular disease (where bleeding more often occurs from the right rather than the left colon, even though diverticula are more common in the left colon). Less-common causes of lower gastrointestinal bleeding are presented in Table 6.3.


Spontaneous bleeding into the skin, or from the nose or mouth, can be a problem for patients with coagulopathy resulting from liver disease.



Jaundice


Usually the relatives notice a yellow discoloration of the sclerae or skin before the patient does. Jaundice is due to the presence of excess bilirubin being deposited in the sclerae and skin. The causes of jaundice are described on page 185. If there is jaundice, ask about the colour of the urine and stools; pale stools and dark urine occur with obstructive or cholestatic jaundice because urobilinogen is unable to reach the intestine. Also ask about abdominal pain; gallstones, for example, can cause biliary pain and jaundice.5






Treatment


The treatment history is very important. Traditional non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, can induce bleeding from acute or chronic damage to the gastrointestinal tract. As described above, many drugs can result in disturbed defaecation. A large number of drugs are also known to affect the liver. For example, acute hepatitis can occur with halothane, phenytoin or chlorothiazide. Cholestasis may occur from a



hypersensitivity reaction to chlorpromazine or other phenothiazines, sulfonamides, sulfonylureas, phenylbutazone, rifampicin or nitrofurantoin. Anabolic steroids and the contraceptive pill can cause dose-related cholestasis. Fatty liver can occur with alcohol use, tetracycline, valproic acid or amiodarone. Large blood-filled cavities in the liver called peliosis hepatis can occur with anabolic steroid use or the contraceptive pill. Acute liver cell necrosis can occur if an overdose of paracetamol (acetaminophen) is taken.




Social history


The patient’s occupation may be relevant (e.g. healthcare workers may be exposed to hepatitis). Toxin exposure can also be important in chronic liver disease (e.g. carbon tetrachloride, vinyl chloride). If a patient has symptoms suggestive of liver disease, ask about recent travel to countries where hepatitis is endemic.


The alcohol history is very important, particularly as alcoholics often deny or understate the amount they consume (see Table 1.3, page 7).6 Contact with anybody who has been jaundiced should always be noted. The sexual history should be obtained. A history of any injections (e.g. intravenous drugs, plasma transfusions, dental treatment or tattooing) in a patient who presents with symptoms of liver disease is important, particularly as hepatitis B or C may be transferred in this way.




The gastrointestinal examination


Examination of the gastrointestinal system includes a complete examination of the abdomen. It is also important to search for the peripheral signs of gastrointestinal and liver disease. Some signs are more useful than others.7



Examination anatomy


An understanding of the structure and function of the gastrointestinal tract and abdominal organs is critical for the diagnosis of gastrointestinal disease (Figure 6.1). The mouth is the gateway to the gastrointestinal tract. It and the anus and rectum are readily accessible to the examiner, and both must be examined carefully in any patient with suspected abdominal disease. The position of the abdominal organs can be quite variable, but there are important surface markings which should be kept in mind during the examination.



The liver is the largest organ in the abdomen; it comprises a large right lobe and smaller left lobe divided into eight segments, including the caudate lobe (segment I) squeezed in between. The lower border of the liver extends from the tip of the right tenth rib to just below the left nipple. Normally the liver is not palpable but it may just be possible to feel the lower edge in healthy people.


The spleen is a lymphoid organ that underlies the ninth, tenth and eleventh ribs posteriorly on the left. It is usually not palpable in health.


The kidneys lie anteriorly 4 finger-breadths from the midline and posteriorly under the twelfth rib. Normally, the right kidney extends 2.5 cm lower than the left. In thin patients, the lower pole of the right kidney may be palpable in health.


The gallbladder is a pear-shaped organ and the fundus (top) is at the tip of the right ninth costal cartilage; it cannot be felt in health. The pancreas is situated in the retroperitoneum (behind the peritoneum), with the head tucked into the C-shaped duodenum and the tail snuggling into the spleen. A huge pancreatic mass may rarely be large enough to be palpable.


The aorta lies in the midline and terminates just to the left of the midline at the level of the iliac crest. A pulsatile mass in the middle of the abdomen is likely to be arising from the aorta and may indicate an aneurysm.


The stomach is usually J-shaped and lies in the left upper part of the abdomen over the spleen and pancreas; it connects with the duodenum. The small intestine ranges from 3 to 10 metres in length and comprises the upper half (duodenum and jejunum) and the lower half (ileum). The small intestine lies over the middle section of the abdomen but is usually impalpable.


The colon is approximately 1.5 metres in length, and from right to left consists of the caecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon, rectum and anal canal (anorectum). The appendix usually lies in the right lower abdominal area, arising posterior-medially from the caecum. The caecum and ascending colon lie on the right side of the abdomen, the transverse colon runs across the upper abdomen from right to left, and then the descending colon and sigmoid and rectum lie on the left side of the abdomen. Rarely, masses arising from the colon will be felt in the abdomen.


Other important anatomical areas include the inguinal canal and the anorectum which will be described later in this chapter in relation to examination of hernias and the rectal examination.




General appearance





Skin


The gastrointestinal tract and the skin have a common origin from the embryoblast. A number of diseases can present with both skin and gut involvement (Figures 6.36.8, Table 6.4).8











Peutz-Jeghersc syndrome


Freckle-like spots (discrete, brown-black lesions) around the mouth and on the buccal mucosa (Figure 6.5) and on the fingers and toes, are associated with hamartomas of the small bowel (50%) and colon (30%), which can present with bleeding or intussusception. In this autosomal dominant condition the incidence of gastrointestinal adenocarcinoma is increased.



Acanthosis nigricans


These are brown-to-black velvety elevations of the epidermis due to confluent papillomas and are usually found in the axillae and nape of the neck (Figure 6.6). Acanthosis nigricans is associated rarely with gastrointestinal carcinoma (particularly stomach) and lymphoma, as well as with acromegaly, diabetes mellitus and other endocrinopathies.



Hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber syndromed)


Multiple small telangiectasia occur in this disease. They are often present on the lips and tongue (Figure 6.7), but may be found anywhere on the skin. When they are present in the gastrointestinal tract they can cause chronic blood loss or even, occasionally, torrential bleeding. An associated arteriovenous malformation in the liver may be present. This is an autosomal dominant condition and is uncommon.



Porphyria cutanea tarda


Fragile vesicles appear on exposed areas of the skin and heal with scarring (Figure 6.8). The urine is dark in this chronic disorder of porphyrin metabolism associated with alcoholism, liver disease and hepatitis C.




Mental state


Assess orientation (page 380). The syndrome of hepatic encephalopathy, due to decompensated advanced cirrhosis (chronic liver failure) or fulminant hepatitis (acute liver failure), is an organic neurological disturbance. The features depend on the aetiology and the precipitating factors (page 188). Patients eventually become stuporous and then comatose. The combination of hepatocellular damage and portosystemic shunting due to disturbed hepatic structure (both extrahepatic and intrahepatic) causes this syndrome. It is probably related to the liver’s failure to remove toxic metabolites from the portal blood. These toxic metabolites may include ammonia, mercaptans, short-chain fatty acids and amines.



The hands


Even the experienced gastroenterologist must restrain his or her excitement and begin the examination of the gastrointestinal tract with the hands. The signs that may be elicited here give a clue to the presence of chronic liver disease. Whatever its aetiology, permanent diffuse liver damage results in similar peripheral signs. However, none of these signs alone is specific for chronic liver disease.




The palms







The arms


Inspect the upper limbs for bruising. Large bruises (ecchymoses) may be due to clotting abnormalities. Hepatocellular damage can interfere with protein synthesis and therefore the production of all the clotting factors (except factor VIII, which is made elsewhere in the reticuloendothelial system). Obstructive jaundice results in a shortage of bile acids in the intestine, and therefore may reduce absorption of vitamin K (a fat-soluble vitamin), which is essential for the production of clotting factors II (prothrombin), VII, IX and X.


Petechiae (pinhead-sized bruises) may also be present. Chronic excessive alcohol consumption can sometimes result in bone marrow depression, causing thrombocytopenia, which may be responsible for petechiae. In addition, splenomegaly secondary to portal hypertension can cause hypersplenism, with resultant excessive destruction of platelets in the spleen; in severe liver disease (especially acute hepatic necrosis), diffuse intravascular coagulation can occur.


Look for muscle wasting, which is often a late manifestation of malnutrition in alcoholic patients. Alcohol can also cause a proximal myopathy (page 391).


Scratch marks due to severe itch (pruritus) are often prominent in patients with obstructive or cholestatic jaundice. This is commonly the presenting feature of primary biliary cirrhosish before other signs are apparent. The mechanism of pruritus is thought to be retention of an unknown substance normally excreted in the bile, rather than bile salt deposition in the skin as was earlier thought.


Spider naevii (Figure 6.10) consist of a central arteriole from which radiate numerous small vessels which look like spiders’ legs. They range in size from just visible to half a centimetre in diameter. Their usual distribution is in the area drained by the superior vena cava, so they are found on the arms, neck and chest wall. They can occasionally bleed profusely. Pressure applied with a pointed object to the central arteriole causes blanching of the whole lesion. Rapid refilling from the centre to the legs occurs on release of the pressure.



The finding of more than two or three spider naevi anywhere on the body is likely to be abnormal. Spider naevi can be caused by cirrhosis, most frequently due to alcohol. In patients with cirrhosis the number of spider naevi may increase or decrease as the patient’s condition changes, as does palmar erythema. They may occur transiently with viral hepatitis. During the second to fifth months of pregnancy, spider naevi frequently appear, only to disappear again within days of delivery. It is not known why they occur only in the upper part of the body, but it may be related to the fact that this is the part of the body where flushing usually occurs. Like palmar erythema they are traditionally attributed to oestrogen excess. Part of the normal hepatic function is the inactivation of oestrogens, which is impaired in chronic liver disease. Oestrogens are known to have a dilating effect on the spiral arterioles of the endometrium, and this has been used to explain the presence of spider naevi, but changes in plasma oestradiol levels have not been found to correlate with the appearance and disappearance of spider naevi.


The differential diagnosis of spider naevi includes Campbell de Morganjspots, venous stars and hereditary haemorrhagic telangiectasia. Campbell de Morgan spots are flat or slightly elevated red circular lesions that occur on the abdomen or the front of the chest. They do not blanch on pressure and are very common. Venous stars are 2- to 3-cm lesions that can occur on the dorsum of the feet, legs, back and the lower chest. They are due to elevated venous pressure and are found overlying the main tributary to a large vein. They are not obliterated by pressure. The blood flow is from the periphery to the centre of the lesion, which is the opposite of the flow in the spider naevus. Lesions of hereditary haemorrhagic telangiectasia (page 228) occasionally resemble spider naevi.


Palpate the axillae for lymphadenopathy (page 229). Look in the axillae for acanthosis nigricans.



The face



Eyes


Look first at the sclerae for signs of jaundice (Figure 6.11) or anaemia. Bitot’sk spots are yellow keratinised areas on the sclera (Figure 6.12). They are the result of severe vitamin A deficiency due to malabsorption or malnutrition. Retinal damage and blindness may occur as a later development. Kayser-Fleischer ringsl (Figure 6.13) are brownish green rings occurring at the periphery of the cornea, affecting the upper pole more than the lower. They are due to deposits of excess copper in Descemet’s membranem of the cornea. Slit-lamp examination is often necessary to show them. They are typically found in Wilson’s disease,n a copper storage disease that causes cirrhosis and neurological disturbances. The Kayser-Fleischer rings are usually present by the time neurological signs have appeared. Patients with other cholestatic liver diseases, however, can also have these rings. Iritis may be seen in inflammatory bowel disease (page 191).





Xanthelasma are yellowish plaques in the subcutaneous tissues in the periorbital region and are due to deposits of lipids (see Figure 4.19, page 57). They may indicate protracted elevation of the serum cholesterol. In patients with cholestasis, an abnormal lipoprotein (lipoprotein X) is found in the plasma and is associated with elevation of the serum cholesterol. Xanthelasma are common in patients with primary biliary cirrhosis.


Periorbital purpura following proctosigmoidoscopy (‘black eye syndrome’) is a characteristic sign of amyloidosis (perhaps related to factor X deficiency) but is exceedingly rare (Figure 6.14).




Salivary glands


Next inspect and palpate the cheeks over the parotid area for parotid enlargement (Table 6.5). Ask the patient to clench the teeth so that the masseter muscle is palpable; the normal parotid gland is impalpable but the enlarged gland is best felt behind the masseter muscle and in front of the ear. Parotidomegaly that is bilateral is associated with alcoholism rather than liver disease per se. It is due to fatty infiltration, perhaps secondary to alcohol toxicity with or without malnutrition. A tender, warm, swollen parotid suggests the diagnosis of parotiditis following an acute illness or surgery. A mixed parotid tumour (a pleomorphic adenoma) is the commonest cause of a lump. Parotid carcinoma may cause a facial nerve palsy (page 343). Feel in the mouth for a parotid calculus, which may be present at the parotid duct orifice (opposite the upper second molar). Mumps also causes acute parotid enlargement which is usually bilateral.


TABLE 6.5 Causes of parotid enlargement







Bilateral


3. Mikulicz* syndrome: bilateral painless enlargement of all three salivary glands. This disease is probably an early stage of Sjögren’s syndrome



Unilateral



* Johann von Mikulicz-Radecki (1850–1905), professor of surgery, Breslau. He described this condition in 1892.


Submandibular gland enlargement is most often due to a calculus. This may be palpable bimanually (Figure 6.15). The examiner’s gloved index finger is placed on the floor of the mouth beside the tongue, feeling between it and fingers placed behind the body of the mandible. It may also be enlarged in chronic liver disease.




The mouth



The teeth and breath


The very beginning of the gastrointestinal tract is, like the very end of the tract, accessible to inspection without elaborate equipment.9 Look first briefly at the state of the teeth and note whether they are real or false. False teeth will have to be removed for a complete examination of the mouth. Note whether there is gum hypertrophy (Table 6.6) or pigmentation (Table 6.7). Loose-fitting false teeth may be responsible for ulcers and decayed teeth may be responsible for fetor (bad breath).


TABLE 6.6 Causes of gum hypertrophy













1 Phenytoin
2 Pregnancy
3 Scurvy (vitamin C deficiency: the gums become spongy, red, bleed easily and are swollen and irregular)
4 Gingivitis, e.g. from smoking, calculus, plaque, Vincent’s* angina (fusobacterial membranous tonsillitis)
5 Leukaemia (usually monocytic)

* Jean Hyacinthe Vincent (1862–1950), professor of forensic medicine and French Army bacteriologist, described this in 1898.


TABLE 6.7 Causes of pigmented lesions in the mouth













1 Heavy metals: lead or bismuth (blue-black line on the gingival margin), iron (haemochromatosis—blue-grey pigmentation of the hard palate)
2 Drugs: antimalarials, the oral contraceptive pill (brown or black areas of pigmentation anywhere in the mouth)
3 Addison’s disease (blotches of dark brown pigment anywhere in the mouth)
4 Peutz-Jeghers syndrome (lips, buccal mucosa or palate)
5 Malignant melanoma (raised, painless black lesions anywhere in the mouth)

Other causes of fetor are listed in Table 6.8. These must be distinguished from fetor hepaticus which is a rather sweet smell of the breath. It is an indication of severe hepatocellular disease and may be due to methylmercaptans. These substances are known to be exhaled in the breath and may be derived from methionine when this amino acid is not demethylated by a diseased liver. Severe fetor hepaticus that fills the patient’s room is a bad sign and indicates a precomatose condition in many cases. The presence of fetor hepaticus in a patient with a coma of unknown cause may be a helpful clue to the diagnosis.


TABLE 6.8 Causes of fetor (bad breath)



















1 Faulty oral hygiene
2 Fetor hepaticus (a sweet smell)
3 Ketosis (diabetic ketoacidosis results in excretion of ketones in exhaled air, causing a sickly sweet smell)
4 Uraemia (fish breath: an ammoniacal odour)
5 Alcohol (distinctive)
6 Paraldehyde
7 Putrid (due to anaerobic chest infections with large amounts of sputum)
8 Cigarettes

Unless the smell is obvious one should get a patient to exhale through the mouth while one sniffs a little of the exhaled air.



The tongue


Thickened epithelium with bacterial debris and food particles commonly causes a coating over the tongue, especially in smokers. It is rarely a sign of disease and is more marked on the posterior part of the tongue where there is less mobility and the papillae desquamate more slowly. It occurs frequently in respiratory tract infections, but is in no way related to constipation or any serious abdominal disorder.


Lingua nigra (black tongue) is due to elongation of papillae over the posterior part of the tongue, which appears dark brown because of the accumulation of keratin. There is no known cause and apart from its aesthetic problems it is symptomless. Bismuth compounds may also cause a black tongue.


Geographical tongue is a term used to describe slowly changing red rings and lines that occur on the surface of the tongue. It is not painful, and the condition tends to come and go. It is not usually of any significance, but can be a sign of riboflavin (vitamin B2) deficiency.


Leucoplakia is white-coloured thickening of the mucosa of the tongue and mouth; the condition is premalignant. Most of the causes of leucoplakia begin with ‘S’: sore teeth (poor dental hygiene), smoking, spirits, sepsis or syphilis, but often no cause is apparent. Leucoplakia may also occur on the larynx, anus and vulva.


The term glossitis is generally used to describe a smooth appearance of the tongue which may also be erythematous. The appearance is due to atrophy of the papillae, and in later stages there may be shallow ulceration. These changes occur in the tongue often as a result of nutritional deficiencies to which the tongue is sensitive because of the rapid turnover of mucosal cells. Deficiencies of iron, folate and the vitamin B group, especially vitamin B12, are common causes. Glossitis is common in alcoholics and can also occur in the rare carcinoid syndrome. However, many cases, especially those in elderly people, are impossible to explain.


Enlargement of the tongue (macroglossia) may occur in congenital conditions such as Down syndrome (page 314) or in endocrine disease, including acromegaly (page 307). Tumour infiltration (e.g. haemangioma or lymphangioma) or infiltration of the tongue with amyloid material in amyloidosis can also be responsible for macroglossia.



Mouth ulcers


This is an important topic because a number of systemic diseases can present with ulcers in the mouth (Table 6.9). Aphthous ulceration is the commonest type seen (Figure 6.16). This begins as a small painful vesicle on the tongue or mucosal surface of the mouth, which may break down to form a painful, shallow ulcer. These ulcers heal without scarring. The cause is completely unknown. They usually do not indicate any serious underlying systemic disease, but may occur in Crohn’so disease or coeliac disease. HIV infection may be associated with a number of mouth lesions (page 457). Angular stomatitis refers to cracks at the corners of the mouth; causes include deficiencies in vitamin B6, vitamin B12, folate and iron.


TABLE 6.9 Causes of mouth ulcers







Common


Uncommon

Rheumatological disease: Behçet’s* syndrome, Reiter’s syndrome




* Halusi Behçet (1889–1948), Turkish dermatologist. He described the disease in 1937.


Hans Reiter (1881–1969), Berlin bacteriologist, described this in 1916.


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