Case Study - April 2008
This is a CT scan of a 52 year old man who presented in an intoxicated state with a self-inflicted laceration to his lower limb. He developed right loin pain whilst in the Accident & Emergency Department.
- What does the CT scan show?
- What risk factors may be relevant in this patient?
- What management options are available?
Case presented by Mr Oliver Wiseman
Reveal Answer
Open answer There is no fixed answer to this question, however your response should be similar to the one below:
- There is a large area of reduced attenuation within the right kidney without any mass. This appearance is compatible with a diagnosis of a renal infarct. The infra-renal abdominal aorta is narrowed by atheroma. The left kidney enhances normally.
- The commonest cause of renal infarction is renal artery thromboembolism originating either locally or within the heart. Important risk factors are smoking, diabetes, hypertension, family history of IHD, hypercholesterolaemia, obesity. A previous history of rheumatic heart disease, atrial fibrillation, infective endocarditis or myocardial infarction is also significant. Other less common causes include trauma, thrombophilias (including Protein C and S deficiency), sickle cell disease and scleroderma.
- The management of renal infarction is controversial due to the paucity of comparative clinical trials into this rare condition. In recent years the general trend has been to use localised fibrinolysis, which has the benefits of targeted therapy with a reduction in the bleeding complications associated with systemic therapy. This technique involves the insertion of thrombolytic agents such as streptokinase, urokinase or tissue-type plasminogen activator into the renal artery during angiography. This should be followed by the long-term use of heparin or warfarin therapy to decrease the risk of further thrombus formation along with secondary prevention of associated peripheral vascular disease risk factors.
Whilst clot lysis is successful in the majority of patients, long-term renal function is preserved in only 50% of patients because of delays in diagnosis and institution of treatment beyond the warm ischaemia time of the kidney (60-90 minutes). Return of renal function to normal is also dependent upon the degree of occlusion of the artery, with sudden complete obstruction causing permanent damage even with treatment. Patients with incomplete occlusion or obstruction at the level of segmental branches, with a good collateral circulation, may result in preservation of renal function even if treatment is instituted many hours later.
Surgical options include embolectomy, angioplasty, aorto-renal bypass, renal autotransplant and vascular excision with end-to-end anastomosis. Their use is generally limited to cases of simultaneous bilateral renal infarction.
The magnetic resonance angiogram (MRA) below shows occlusion of the right renal artery with associated irregularity of the lower abdominal aorta and stenoses at the origins of both common iliac arteries.
