Материал: 100_Cases_in_Clinical_Medicine

CASE 100: PAIN IN THE LEG

History

A 22-year-old woman is admitted to hospital with a painful left leg. She uses intravenous drugs and injects into veins in the arms and the groins. The left leg has become swollen and painful over the last week. She has had two previous admissions to hospital within the last 6 months, once for an overdose of heroin and once for an infection in the left arm. She smokes 20 cigarettes daily and drinks up to 40 units of alcohol per week.

Examination

Her pulse is 84/min and regular. Her blood pressure is 124/74 mmHg. Her temperature is 37.2°C. The heart sounds are normal and there are no abnormal findings on examination of the respiratory system. She has a swollen left calf with some local tenderness. There are puncture sites in both groins but no obvious sepsis.

INVESTIGATIONS

Ultrasound of left leg: venous thrombus extending into the left femoral vein

Venous access is difficult but a line is inserted in the right arm and she is treated with subcutaneous low-molecular-weight heparin, intravenous vitamins and benzodiazepines, and a methadone-replacement regime. On the fourth day of her admission she became much more unwell.

Further examination

Her pulse is 112 per minute and regular. Her blood pressure is 88/50 mmHg although she seems warm and well perused. The respiratory rate is18/min, jugular venous pressure is not raised, there are no new heart murmurs and oxygen saturation is 97 per cent on room air. Her temperature is 37.6°C.

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ANSWER 100

The initial diagnosis was a deep vein thrombosis. This complication is not unusual in intravenous drug users and can be associated with sepsis although there was no sign of this on the initial investigations. She has been treated for the thrombosis and for alcohol withdrawal and her opiate use.

There are a number of possibilities for her acute deterioration. The deep vein thrombosis would have predisposed her to a pulmonary embolus, but the normal respiratory rate, lack of elevation of jugular venous pressure and normal oxygen saturation make this unlikely. As an intravenous drug user she might have taken more drugs even under supervision in hospital.

The tachycardia and lowered blood pressure raise the possibility of haemorrhage which might be precipitated by the anticoagulants. However, the raised CRP, white cell count and abnormal electrolytes in a warm, well-perfused patient suggest sepsis as the likely cause. In an intravenous drug user one would think of infective endocarditis which may occur on the valves of the right side of the heart and be more difficult to diagnose. Lung abscesses from septic emboli are another possibility in an intravenous drug user with a deep vein thrombosis, and a chest X-ray should be taken although the lack of respiratory symptoms makes this less likely. In this case the intravenous line has been left in place longer than usual because of the difficulties of intravenous access and it has become infected. Lines should be inspected every day, changed regularly and removed as soon as possible. The previous hospital admissions raise then possibility of infections such as methicillin-reistant Staphylococcus aureus (MRSA). In this case MRSA was found in blood cultures and treated with intravenous vancomycin with good effect.

On recovery and discharge there were problems with the question of anticoagulation. Warfarin treatment raised difficulties because of the unreliability of dosing, attendance at anticoagulant clinics and blood sampling. It was decided to continue treatment as an outpatient with subcutaneous heparin for 6 weeks.

KEY POINTS

•Patients using intravenous drugs often pose problems in venous access, and sampling for tests such as international normalized ratio (INR).

•Indwelling venous lines should be changed regularly and removed as soon as possible.

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INDEX

References are by case number with relevant page number(s) following in brackets. References with a page range e.g. 25(68–70) indicate that although the subject may be mentioned only on one page, it concerns the whole case.

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