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ANSWER 88

The liver function tests show a predominantly obstructive picture with raised alkaline phosphatase and gamma-glutamyl transpeptidase, while cellular enzymes are only slightly raised. The symptoms and investigations are characteristic of primary biliary cirrhosis, an uncommon condition found mainly in middle-aged women. In the liver there is chronic inflammation around the small bile ducts in the portal tracts. Hypercholesterolaemia, xanthelasmata and xanthomata are common. The dry eyes and dry mouth may occur as part of an associated sicca syndrome. Itching occurs because of raised levels of bile salts, and can be helped by the use of a binding agent such as cholestyramine which interferes with their reabsorption. The presence of antimitochondrial antibodies in the blood is typical of primary biliary cirrhosis. These antibodies are found in 95 per cent of cases.

Hypothyroidism might explain some of her symptoms but the normal thyroid-stimulating hormone (TSH) level shows that her current dose of 150 &g thyroxine is providing adequate replacement. The thyroid antibodies reflect the autoimmune thyroid disease which is associated with other autoantibody-linked conditions such as primary biliary cirrhosis.

The diagnosis is confirmed by a liver biopsy. This should only be carried out after an ultrasound confirms that there is no obstruction of larger bile ducts. Ultrasound will help to rule out other causes of obstructive jaundice although the clinical picture described here is typical of primary biliary cirrhosis. No treatment is known to affect the clinical course of this condition.

KEY POINTS

•The pattern of liver enzyme abnormalities usually reflects either an obstructive or hepatocellular pattern.

•Symptoms such as itching have a wide differential diagnosis. Dealing with the underlying cause, wherever possible, is preferable to symptomatic treatment.

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CASE 89: LOSS OF CONSCIOUSNESS

History

A 40-year-old man is admitted to the emergency department having been found unconscious at home by his wife on her return from work in the evening. He has suffered from insulin-dependent diabetes mellitus for 18 years and his diabetic control is poor. He has had recurrent hypoglycaemic episodes, and has been treated in the emergency department on two occasions for this. Over the past few weeks he has developed pain in his right foot. His general practitioner diagnosed cellulitis and he has received two courses of oral antibiotics. This has made him feel unwell and he has complained to his wife of fatigue, anorexia and feeling thirsty. In his medical history he had a myocardial infarction 2 years ago. He has had bilateral laser treatment for proliferative diabetic retinopathy. He was a builder but is now unemployed. He smokes 25 cigarettes per week and drinks 30 units of alcohol per week. His treatment is twice-daily insulin, he checks his blood glucose irregularly at home.

Examination

He is clinically dehydrated with reduced skin turgor and poor capillary return. His pulse is regular and 116/min. His blood pressure is 92/70 mmHg lying, 72/50 mmHg sitting up. He seems short of breath with a respiratory rate of 30/min. Otherwise, examination of his respiratory and abdominal systems is normal. He has an ulcer on the third toe of his right foot and the foot looks red and feels warm. He is rousable only to painful stimuli. There is no focal neurology. Funduscopy shows bilateral scars of laser therapy.

INVESTIGATIONS

Questions

•What is the cause for this man’s coma?

•How would you manage this patient?

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ANSWER 89

This man has signs of dehydration and the high urea with a normal creatinine is consistent with this. He is acidotic. The blood glucose level is not given but the picture is likely to represent hyperglycaemic ketoacidotic coma. The key clinical features on examination are dehydration and hyperventilation, and the triggering problem with the infection in the foot. A persistently high sugar level induced by his infected foot ulcer causes heavy glycosuria triggering an osmotic diuresis. This leads to hypovolaemia and reduced renal blood flow causing prerenal uraemia. The extracellular hyperosmolality causes severe cellular dehydration, and loss of water from his brain cells is the cause of his coma. Decreased insulin activity with intracellular glucose deficiency stimulates lipolysis and the production of ketoacids. He has a high anion gap metabolic acidosis due to accumulation of ketoacids (acetoacetate and 3-hydroxybutyrate). The anion gap is calculated from the equation:

[Na'] ' [K'] * ([Cl*] ' [HCO*3 ])

and is normally 10–18 mmol/L; in this case it is 31.5 mmol/L. Ketones cause a characteristically sickly sweet smell on the breath of patients with diabetic ketoacidosis (about 20 per cent of the population cannot smell the ketones). The metabolic acidosis stimulates the respiratory centre leading to an increase in the rate and depth of respiration (Kussmaul breathing) producing the reduction in paCO2 as respiratory compensation for the acidosis. In older diabetic patients there is often evidence of infection precipitating these metabolic abnormalities, e.g. bronchopneumonia, infected foot ulcer.

The differential diagnosis of coma in diabetics includes non-ketotic hyperglycaemic coma, particularly in elderly diabetics, lactic acidosis especially in patients on metformin, profound hypoglycaemia, and non-metabolic causes for coma, e.g. cerebrovascular attacks and drug overdose. Salicylate poisoning may cause hyperglycaemia, hyperventilation and coma, but the metabolic picture is usually one of a dominant respiratory alkalosis and mild metabolic acidosis.

The aims of management are to correct the massive fluid and electrolyte losses, hyperglycaemia and metabolic acidosis. Rapid fluid replacement with intravenous normal saline and potassium supplements should be started. In patients with cardiac or renal disease, a central venous pressure (CVP) line is mandatory to control fluid balance. Regular monitoring of plasma potassium is essential, as it may fall very rapidly as glucose enters cells. Insulin therapy is given by intravenous infusion adjusted according to blood glucose levels. A nasogastric tube is essential to prevent aspiration of gastric contents, and a bladder catheter to measure urine production. Antibiotics and local wound care should be given to treat this man’s foot ulcer. In the longer-term it is important that this patient and his wife are educated about his diabetes and that he has regular access to diabetes services. His smoking and alcohol consumption will also need to be addressed. There may be social issues to be considered in relation to his unemployment.

KEY POINTS

•Dehydration, tachypnoea and ketosis are the key clinical signs of diabetic ketoacidosis.

•Twenty per cent of the population (and therefore doctors) cannot smell ketones.

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CASE 90: COUGH AND BREATHLESSNESS

History

A 69-year-old widower smoked 20 cigarettes a day for over 40 years but then gave up 9 months ago when his first grandchild was born. He has had a cough with daily sputum production for the last 20 years and has become short of breath over the last 3 years. He coughs up a little white or yellow sputum every morning. He has put on weight recently and now weighs 100 kg. His ankles have become swollen recently and his exercise tolerance has decreased. He can no longer carry his shopping back from the supermarket 180 m (200 yards) away. He worked as a warehouseman until he was 65 and has become frustrated by his inability to do what he used to do. He is not able to look after his grandchild because he feels too short of breath.

There is no other relevant medical or family history. He lives alone and has a cat and a budgerigar at home.

His general practitioner (GP) gave him a salbutamol metered-dose inhaler which produced no improvement in his symptoms.

Examination

He is overweight. He appears to be centrally and peripherally cyanosed and has some pitting oedema of his ankles. His jugular venous pressure is raised 3 cm. He has poor chest expansion. There are some early inspiratory crackles at the lung bases.

INVESTIGATIONS

FEV1: forced expiratory volume in 1 s; FVC, forced vital capacity; FER, forced expiratory ratio; PEF, peak expiratory flow.

His chest X-ray is shown in Fig. 90.1.

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Figure 90.1 Chest X-ray.

Questions

•What is the likely diagnosis?

•What management is appropriate?

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ANSWER 90

The most likely diagnosis is chronic obstructive pulmonary disease (COPD). The physical signs and chest X-ray indicate overinflation. The early inspiratory crackles are typical of COPD.

Treatment with bronchodilators should be pursued looking at the effect of $2-agonists and anticholinergic agents, judging the effect from the patient’s symptoms and exercise tolerance rather than spirometry. Theophylline may sometimes be useful as a third-line therapy but has more side-effects.

With this degree of severity, inhaled corticosteroids and long-acting bronchodilators (salmeterol/formoterol or tiotropium) would be appropriate inhaled therapy. Careful attention would need to be given to inhaler technique.

He is cyanosed and has signs of right-sided heart failure (cor pulmonale). Blood gases should be checked to see if he might be a candidate for long-term home-oxygen therapy (known to improve survival if the pressure of arterial oxygen (paO2) in the steady-state breathing air remains !7.2 kPa). Gentle diuresis might help the oedema although oxygen would be a better approach if he is sufficiently hypoxic. Annual influenza vaccination should be recommended and Streptococcus pneumoniae vaccination should be given. Antibiotics might be kept at home for infective exacerbations.

Exercise tolerance will be reduced by his obesity and by lack of muscle use. A weightreducing diet should be started. If he has the motivation to continue exercising, then a pulmonary rehabilitation programme has been shown to increase exercise tolerance by around 20 per cent and to improve quality of life. Other more dramatic interventions such as lung-reduction surgery or transplantation might be considered in a younger patient. Depression is often associated with the poor exercise tolerance and social isolation, and this should be considered.

COPD is often regarded as a condition where treatment has little to offer. However, a vigorous approach tailored to the need of the individual patient can provide a worthwhile benefit.

KEY POINTS

•In COPD $2-agonists and anticholinergic agents produce similar effects or a greater response from anticholinergics. The combination may be helpful. In contrast, in asthma $2-agonists produce a greater effect.

•Assessment for home oxygen should be made in a stable state on optimal inhaled therapy.

•Exercise and diet are important elements in the management of COPD.

•Depression is common in chronic conditions such as COPD.

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CASE 91: PAIN IN THE FOOT

History

A 65-year-old man presents with an ulcer on the dorsum of his right foot. He noticed a sore area on the right foot 3 weeks ago and this has extended to an ulcerated lesion which is not painful. He has complained of pain in the legs for some months. This pain comes on when he walks and settles down when he stops.

He had an inguinal hernia repaired 2 years ago and he stopped smoking then on the advice of the anaesthetist. Previously he smoked 20 cigarettes per day. He drinks four pints of beer at weekends. His father died of a myocardial infarction aged 58 years.

Examination

His blood pressure is 136/84 mmHg. The respiratory, cardiovascular and abdominal systems are normal. There is a 3 cm ulcerated area with a well-demarcated edge on the dorsum of the right foot. The posterior tibial pulses are palpable on both feet, and the dorsalis pedis on the left. The capillary return time is 4 s. On neurological examination there is some loss of light touch sensation in the toes. Varicose veins are present in the long saphenous distribution on both legs.

INVESTIGATIONS

Question

• What is the likely diagnosis?

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ANSWER 91

The presence of varicose veins raises the possibility of a venous ulcer related to poor venous return. However, venous ulcers are usually found around the medial malleolus and are often associated with skin changes of chronic venous insufficiency. This has the features of an ulcer caused by arterial rather than venous ulceration or a mixed aetiology. Arterial ulcers are often on the dorsum of the foot. Arterial ulcers tend to be deeper and more punched out in appearance. The left dorsalis pedis pulse is not palpable and the capillary return time is greater than the normal value of 2 s. The story of pain in the legs on walking requires a little more detail but it is suggestive of intermittent claudication related to insufficient blood supply to the exercising calf muscles.

The raised HbA1c suggests diabetes and prolonged hyperglycaemia. In diabetes the arterial involvement may be in small vessels with greater preservation of the pulses. The peripheral sensory neuropathy may also be associated with diabetes and lead to unrecognized trauma to the skin which then heals poorly. Other risk factors for arterial disease are the family history and the history of smoking.

Further investigations would include measurement of the ankle:brachial blood pressure ratio. If this is less than 0.97 it suggests arterial disease, and a low index would be a contraindication to pressure treatment in trying to heal the ulcer.

Ultrasonic angiology would help to identify the anatomy of the arterial circulation in the lower limbs and would show if there are correctable narrowings of major vessels. Good control of diabetes can slow progression of complications such as neuropathy and microvascular disease. Care of the feet is a very important part of the treatment of diabetes and should be a regular element of follow-up.

KEY POINTS

•The position and nature of ulcers provide clues to their cause.

•Diabetic feet are particularly vulnerable because of sensory loss, arterial insufficiency and high sugars. Foot care is an important element of regular diabetic management.

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CASE 92: A HEALTHY MAN?

History

A 50-year-old man has a health screen as part of an application for life insurance. He has no symptoms. He smokes 15 cigarettes per day and drinks 10 units of alcohol per week. In his family history his father died of a myocardial infarction aged 56 years.

Examination

He weighs 84 kg and is 1.6 m (5 ft 8 in) tall. His blood pressure is 164/98 mmHg. Examination is otherwise normal.

INVESTIGATIONS

His electrocardiogram (ECG) is shown in Fig. 92.1.

II

Figure 92.1 Electrocardiogram.

Question

• What is the appropriate management?

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