Graham Hughes1 and Shirish Sangle2
(1)
The London Lupus Centre, London Bridge Hospital, London, UK
(2)
Louise Coote Lupus Unit, St Thomas’ Hospital, London, UK
Abstract
Perhaps because of the overlap of some cases of APS with lupus, recognition of the importance and extent of renal involvement in primary APS was initially slow. However, it is now known that a variety of renal pathologies can be seen.
Perhaps because of the overlap of some cases of APS with lupus, recognition of the importance and extent of renal involvement in primary APS was initially slow. However, it is now known that a variety of renal pathologies can be seen.
11.1 Renal Artery Thrombosis
There are many reports of acute renal artery occlusion in APS – both unilateral and bilateral. Clinically the features include renal angle pain, haematuria, labile hypertension and, in some cases, acute renal failure.
Clearly an acute medical emergency, frequent options range from anticoagulation, through angioplasty to nephrectomy – the latter sometimes required for blood pressure control.
11.2 Renal Vein Thrombosis
Recognised in APS as well as aPL-positive lupus patients, renal vein thrombosis can be unilateral or bilateral. One of our cases presented post-partum with bilateral renal vein thrombosis and severe nephrotic syndrome.
11.3 Renal Artery Stenosis
The original description of the syndrome included the observation, “these patients blood pressure often fluctuates, apparently correlating with the severity of the livedo, suggesting a possible reno-vascular aetiology. However, this group of patients rarely has primary renal disease”.
We now know that renal artery stenosis underlies some of these cases (Fig. 11.1).
Figure 11.1
Magnetic resonance arteriography showing renal artery stenosis in Hughes syndrome
Studies of renal artery stenosis in APS found that, as might be expected, hypertension was a common accompaniment. This observation led to two others: firstly, that in APS, 80% of hypertensive patients were found to have livedo. And secondly, that in some APS patients, with renal artery stenosis, careful anticoagulation improves blood pressure control – another example of anticoagulation benefit in APS, even in the absence of overt thrombosis.
11.4 Thrombotic Microangiopathy
Glomerular thrombosis has long been recognised as a histological feature in some lupus kidney biopsy specimens. Indeed, careful studies have suggested that glomerular thrombi featured in up to 50% of lupus nephritis biopsies. It became clear that the association was with the presence of aPL, and in 1992, Amigo and her colleagues in Mexico reported the same pathology in primary APS.
Although thrombotic microangiopathy can be a result of a number of conditions, it is an important component of APS. In lupus, the search for aPL-related microthrombic lesions is now considered one of the main indications for renal biopsy.
Figure 11.2
A renal biopsy showing thrombotic micro-angiopathy in a patient with Hughes syndrome. This young patient presented with hypertension, hematuria and impaired renal function
11.5 Renal Transplantation
The presence of aPL has long been recognised as a predictor of access thrombosis in dialysis treatment of end stage renal disease. Much more serious is the probable increased risk of failure of renal transplantation of aPL-positive individuals. Many published reports cite the higher rejection rate in aPL-positive individuals – not only in renal transplants – the problems largely being peri- and post-operative thrombosis.
However, for some patients, the prothrombotic risk continues for life and thrombosis in the transplanted organ can occur years after the surgical procedure.
Recognition of the thrombotic risk in APS and its appropriate management with anticoagulation has had a major impact in this branch of surgery, as it has in others.
To quote two transplant surgeons:
In the United States in 2003, the average cost of a kidney transplant was estimated to be $117,317. The expense of losing a transplanted heart or liver to aPL-associated thrombosis not only includes healthcare dollars but often includes the loss of a patient’s life.
The encouraging news is that once aPL are identified pre-transplant, prophylactic anticoagulation appears capable of averting aPL associated allograft event. (Wagenknecht & McIntyre. Chapter in Hughes Syndrome. Ed. Khamashta MA. Springer).