Reversal of thrombocytopenia following oral anticoagulation in two patients with primary antiphospholipid syndrome

Cryptic conspirators: a conversation about thrombocytopenia and antiphospholipid syndrome

Purpose of review

Although antiphospholipid syndrome (APS) is best known for conveying increased risk of thrombotic events and pregnancy morbidity, thrombocytopenia is also recognized as a common association. In this review, we will explore the relationship between thrombocytopenia and APS, highlighting our evolving understanding – and persistent knowledge gaps – through clinically oriented questions and answers.

Recent findings

A history of thrombocytopenia likely portends a more severe APS phenotype (including increased risk of thrombosis). Although the pathophysiology underlying thrombocytopenia in APS has yet to be definitively revealed, mechanisms that play a role (at least in subsets of patients) include: immune thrombocytopenic purpura/ITP-like autoantibodies against platelet glycoproteins; antiphospholipid antibody (aPL)-mediated platelet activation and consumption; and potentially life threatening thrombotic microangiopathy. Although thrombocytopenia is often ‘mild’ in APS (and therefore, may not require specific therapy), there are causes of acute-onset thrombocytopenia that mandate emergent work-up and treatment. When APS-related thrombocytopenia does require therapy, the approach must be individualized (requiring an understanding of pathophysiology in the particular APS patient). For patients with ITP-like disease, rituximab is emerging as a popular approach to treatment; in contrast, there are hints that thrombopoietin mimetics may be associated with elevated thrombotic risk.

Summary

Thrombocytopenia is common in APS, and is likely associated with more severe disease. Improved understanding of thrombocytopenia in APS has the potential to improve risk stratification, reveal novel aspects of APS pathophysiology, and lead to treatments that are more individualized and holistic.

Autoimmune thyroid disease and antiphospholipid antibodies

OBJECTIVE

Autoimmune thyroid disease (ATD) is associated with circulating autoantibodies reactive with epitopes on thyroid tissue and that are thought to be pathogenic in the development of these diseases. Antiphospholipid antibodies (APLA) are a family of immunoglobulins that recognize a variety of plasma proteins in association with anionic phospholipids. These antibodies may lead to a number of clinical syndromes including venous and arterial thromboses, thrombocytopaenia, and recurrent fetal loss. We have studied the prevalence of APLA in patients with ATD and have determined the prevalence of the APLA syndrome among APLA-positive patients.

DESIGN

The study was a retrospective survey of patients with autoimmune thyroid disease attending the endocrinology clinic of a tertiary care academic hospital.

PATIENTS AND MEASUREMENTS

One hundred and thirty patients with autoimmune thyroid disease from the endocrinology clinic at our hospital were studied. 84% had chronic thyroiditis and 16% had Graves' disease. Free T4 and thyroid stimulating hormone (TSH) levels, antimicrosomal and antithyroglobulin antibodies, and an antiphospholipid antibody test were performed on all subjects.

RESULTS

43% of patients with chronic thyroiditis and 43% of patients with Graves' disease were APLA positive, with an overall rate of 43% APLA positivity among patients with ATD. Of the 56 patients that were APLA positive, forty-eight (86%) had APLA of the IgG subtype, four (7%) had IgM antibodies, and nine (16%) had both IgG and IgM antibodies. None of the patients had clinical evidence of the APLA syndrome.

CONCLUSIONS

We conclude that the prevalence of APLA in ATD is increased compared to healthy individuals but that this is likely to be an epiphenomenon. However, prolonged follow up is necessary in order to determine the true clinical significance of these antibodies in ATD patients.

Splenectomy for refractory thrombocytopenia in the antiphospholipid syndrome

OBJECTIVE

Thrombocytopenia, usually mild, is one of the clinical criteria of the antiphospholipid syndrome (APS). Rarely, this disorder requires treatment and, due to the shared characteristics with idiopathic thrombocytopenic purpura (ITP), similar rules are followed. We report our experience in patients who required splenectomy after being refractory to steroids and immunosuppressive therapy.

METHODS

Fifty-five APS patients with a platelet count of < 100 x 10(9)/l at least twice were analysed retrospectively. Therapeutic response or remission was considered when the platelet count was > 100 x 10(9)/l after 1 month and with no relapse on stopping or tapering the steroid dose. No response or refractory disease was defined as an absence of increase in platelet count, a total count that never exceeded 50 x 10(9)/l during treatment or when the dose requirements were such that the patient developed serious side-effects.

RESULTS

Fifty patients were classified as having secondary APS associated with systemic lupus erythematosus (SLE) and five were identified as primary APS (PAPS). Splenectomy was performed in 11 cases (20%), two PAPS and nine SLE-APS, with an average time of 28 +/- 9 months after the development of thrombocytopenia. Eight patients were initially characterized as ITP (six SLE-APS, two PAPS) with an average time of 4.4 +/- 1.1 yr until the APS diagnosis. All but two were responsive to splenectomy.

CONCLUSION

Splenectomy was required in 11 (20%) of the patients with APS-associated thrombocytopenia. There was a high rate of good and long-term response.

Primary antiphospholipid syndrome and cerebral atrophy: a rare association?

Neurologic complications are common in patients with antiphospholipid syndrome. In this article, we report the case of a young woman with neurologic disorders, a history of hypertension and transient ischemic attacks, and cerebral atrophy associated with primary antiphospholipid syndrome (PAPS). Magnetic resonance imaging of the brain showed multiple ischemic lesions and remarkable atrophy of frontal and parietal lobes. Cerebral atrophy in patients with PAPS can be considered as a feature of this disease. The case is discussed on the basis of relevant past literature. Although there are few reports on neuroradiologic findings in patients with PAPS, cerebral atrophy has been described. Because PAPS is more frequently recognized today than in the past, this condition should be included in the differential diagnosis of cerebral atrophy, particularly in young patients.