Vascular

CASE 53: reSt pain in the loWer limb

history

A 70-year-old man presents to the emergency department complaining of a dull pain in the dorsum of the right foot for the past 6 weeks. The pain is worse at night, waking him from sleep, and is relieved by hanging his leg over the edge of the bed. For the past week he has been sleeping in a chair to alleviate the pain. He is known to have hypertension and hypercholesterolaemia. His past history includes coronary artery bypass grafting 6 years ago. He lives with his wife and is fully independent.

examination

The right foot has a red tinge and is swollen. The right little toe is dusky. The right foot feels cool when compared with the left, with delayed capillary refill. The femoral pulse is palpable on both sides. Popliteal, dorsalis pedis and posterior tibial pulses are palpable on the left leg, but pulses below the femoral are absent on the right. The ABPI measures 0.9 on the left and 0.35 on the right.

The patient is admitted for an urgent duplex ultrasound, which suggest occlusion of the right superficial femoral artery. The following day an intra-arterial angiogram is carried out (Figure 53.1).

Figure 53.1 angiogram of the right lower limb.

Questions

•How do you explain the symptoms and signs?

•A decision is made to carry out arterial reconstruction – what choices of graft materials are available?

•What are the complications of surgery?

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100 Cases in Surgery

ANSWER 53

Pain in the foot that is worse at night and is relieved by dependence is classical of ischaemic rest pain and is the result of poor tissue perfusion and oxygenation. An ABPI of 0.35 is compatible. Discolouration of the toe suggests impending gangrene. The patient should be made comfortable using opiate analgesia. He should be treated with low-molecular-weight or unfractionated heparin, pending investigation and treatment.

The angiogram reveals occlusion of the superficial femoral artery on the right (Figure 53.2). The popliteal artery reforms at the level of the knee via collateral vessels. If attempts at recanalizing the vessel using angioplasty are unsuccessful, then the patient should be considered for a femoral-popliteal bypass graft.

Figure 53.2 arterial angiogram showing occlusion of the right superficial femoral artery and the popliteal artery reforming at the knee (arrows).

The material of choice for bypass grafting is autogenous vein. The long saphenous vein is most widely used but arm veins/the short saphenous vein are other options if the long saphenous vein has already been used (e.g. previous bypass, coronary artery grafting) or is small in calibre. Other options include prosthetic grafts (e.g. Dacron, polytetrafluoroethylene) or umbilical vein allografts. The long-term patency of prosthetic grafts is inferior compared with autogenous vein.

!Complications of bypass surgery

KEY POINTS

•rest pain indicates inadequate tissue perfusion.

•urgent investigation and treatment is required to salvage the limb.

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Vascular

CASE 54: poStoperative limb SWelling

history

You are asked to review a 68-year-old woman on the ward. She had an anterior resection for a rectal tumour 5 days ago. Postoperative recovery has been unremarkable and she has started to eat and drink and opened her bowels today. You have been asked to examine her as she is complaining of pain and swelling of the left leg. There is no history of trauma to the leg.

examination

Her temperature is 37.5°C and her pulse rate is 99/min. The abdomen is soft and non-tender. The left leg is swollen to mid-thigh, with erythema of the skin. The calf feels warm and is tender to touch. The foot pulses are normal.

INVESTIGATIONS

Questions

•What is the most likely diagnosis? What are the differentials?

•What investigation should be carried out next?

•What are the risk factors associated with this condition?

•How should this condition be treated?

•What are the long-term sequelae of this condition?

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100 Cases in Surgery

ANSWER 54

The most likely diagnosis is a deep vein thrombosis (DVT). Clinical examination is notoriously inaccurate for making the diagnosis, as the degree of swelling and pain varies and patients can be symptomless.

!Differential diagnoses

•Cellulitis

•lymphangitis

•Soft tissue injury

•lymphoedema

•haematoma

•arterial insufficiency

•ruptured baker’s cyst

A normal D-dimer assay (fibrin degradation products) would usually exclude a diagnosis of DVT, but is not useful in this case as the recent surgery means that it will be positive regardless. The diagnosis is best confirmed using duplex ultrasonography of the deep veins.

!Risk factors for deep vein thrombosis

Anticoagulation is the mainstay of treatment, aimed at preventing extension of the thrombus and reducing the risk of pulmonary embolism. Therapeutic low-molecular-weight heparin and warfarin are commenced at the same time. Heparin is stopped when the international normalized ratio (INR) becomes therapeutic. The target INR is usually in the range of 2–3. Some authorities do not treat DVT confined to the calf because of the very low risk of pulmonary embolism.

DVT can result in venous hypertension, and long-term consequences include the post-thrombotic syndrome, which consists of leg pain, swelling, lipodermatosclerosis and ulceration.

KEY POINTS

•treatment should be commenced once a Dvt has been diagnosed clinically.

•the diagnosis is confirmed with ultrasound.

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