Sneddon's syndrome and antithrombin III

Livedo racemosa as a marker of increased risk of recurrent thrombosis in patients with negative anti-phospholipid antibodies

BACKGROUND AND OBJECTIVE

Livedo reticularis racemosa and cerebrovascular lesions characterize Sneddon's syndrome. We report 23 patients with livedo racemosa and describe the association with thrombotic events. Our objective was to determine whether livedo racemosa may be an independent clinical marker for the development of thrombotic events in patients who test negative for anti-phospholipid antibodies.

METHODS

Twenty-three patients with widespread livedo racemosa were studied. None of the patients were positive for anti-phospholipid antibodies. The clinical protocol included a register of thrombotic events, fetal death or miscarriages, hypertension, and valvular heart disease. Cerebral MRI and echocardiography were systematically performed in all patients.

RESULTS

Nineteen patients (82.60%) had thrombotic events. Fifteen (65.21%) had arterial thrombosis and eleven (47.82%) presented venous occlusions. Seven patients (30.43%) had both arterial and venous thrombosis. Fetal losses were recorded in seven cases (30.43%), with a total number of 33; five patients had 3 or more fetal losses. Eleven out of 23 patients (47.82%) had valvular heart disease. Arterial hypertension was detected in 16 (69.56%) patients. Four patients did not have thrombotic events but had other clinical manifestations. After anti-coagulation therapy was withdrawn, a new thrombotic event was observed in 9 out of the 14 treated patients (64.28%).

CONCLUSIONS

Livedo racemosa seems to be a good clinical marker for the detection of hypercoagulable states even in the absence of anti-phospholipid antibodies or other known biologic markers of thrombosis. Long-term anti-coagulation is probably warranted in patients with livedo racemosa and a previous thrombotic event.

Protein Z deficiency in antiphospholipid-negative Sneddon's syndrome

BACKGROUND

Sneddon's syndrome is characterized by the association of ischemic cerebrovascular events and widespread livedo racemosa. The pathophysiology of Sneddon's syndrome remains elusive, but various prothrombotic abnormalities have been previously reported in this setting. Low levels of protein Z, a downregulator of coagulation, have been recently linked to an increased risk of arterial thrombosis. The purpose of this study was to investigate the levels of protein Z in a series of Sneddon's syndrome patients without circulating antiphospholipid antibodies in comparison with an age- and sex-matched control population.

METHODS

Twenty-six patients and 78 healthy controls had determination of their protein Z blood levels by an enzyme-linked immunoassay test. Patients' thrombotic and vascular risk factors, including tobacco smoking, arterial hypertension, oral contraceptive agents, dyslipidemia, factor V Leiden, and factor II mutation were recorded.

RESULTS

Protein Z plasma levels were significantly lower in patients (mean 1.47 mg/L) than in controls (mean 1.93 mg/L) (P=0.02). Prevalence of protein Z deficiency (level <1 mg/L) was significantly higher (P=0.001) among patients (31%) than among controls (3.8%). Factor V Leiden and heavy smoking were observed in 4 and 7 patients, respectively.

CONCLUSIONS

Sneddon's syndrome could be viewed as the peculiar clinical expression of various and sometimes associated coagulation abnormalities. Low levels of protein Z may account, at least partly, for the thrombotic events observed in Sneddon's syndrome and shed a new light on its pathophysiology. Clinical implications for protein Z deficiency in this setting deserve further investigations.

Diagnostic impact and sensitivity of skin biopsies in Sneddon's syndrome. A report of 15 cases

BACKGROUND

Sneddon's syndrome is defined as a combination of idiopathic livedo racemosa generalisata and symptoms of cerebrovascular defect. The disease usually starts with vascular symptoms in the epidermis, with neurological deficits becoming evident later. For this reason, histological examination of skin biopsies and determination of arteriolar occlusion is of particular importance for reliable categorization and early diagnosis. To date, these methods have been considered to be too insensitive.

OBJECTIVES

To evaluate the sensitivity of skin biopsies in Sneddon's syndrome.

METHODS

We took a total of five deep punch biopsies (4 mm) from different areas of the livedo (three from white and two from red areas) in 15 patients. Present knowledge of the pathogenic relationships and the particular anatomical features of the skin were taken into account.

RESULTS

The method had a sensitivity of 27% with one biopsy, 53% with two biopsies and 80% with three biopsies taken from white areas in all cases.

CONCLUSIONS

Skin biopsies using the method presented achieved a high sensitivity, suggesting that the diagnosis in clinically suspected cases could be confirmed in the majority of cases with this technique.