Idiopathic hypereosinophilic syndrome: a new cause of vasculitis of the central nervous system

Abstract

Idiopathic hypereosinophilic syndrome (IHES) is a primary haematological condition characterised by persistent, otherwise unexplained hypereosinophilia sufficient to cause organ damage. Various neurological complications are reported, but very few have mentioned CNS pathology and none has included CNS vasculitis. Our objective here is to report IHES as a new cause of histopathologically confirmed CNS vasculitis. A 39-year-old man presented with a relapsing sub-acute encephalopathy, with severe headaches, confusion and drowsiness, myoclonus, ataxia and papilloedema. He had a history of nephrotic syndrome 18 years earlier, stable for the past 5 years on low-dose corticosteroids and low-dose tacrolimus (2 mg bd); lichen planus, and (15 years previously) aloplecia totalis. On admission, he had a marked peripheral eosinophilia (up to 9.1 × 10(9)/dL), which—it subsequently became clear—had been intermittently present for 16 years. After extensive investigation, biopsies of brain and bone marrow confirmed diagnoses of cerebral vasculitis, with lymphocytic and macrophage (but not eosinophilic) cellular infiltration of blood vessel walls, and IHES. CNS vasculitis can therefore now be added to the list of neurological complications of IHES. A dramatic and sustained neurological improvement, and likewise of the eosinophilia, following treatment with corticosteroids and cyclophosphamide, emphasises the tractability of this newly described form of CNS vasculitis.

Idiopathic hypereosinophilic syndrome with pulmonary hypertension

“…Other lab reports consisted of: AST 59.1 U/L (reference range ¼ 15-40 IU/L); ALT 112.7 U/L (reference range ¼ 9-50 IU/L); ALP 178.2 U/L (reference range ¼ 45-125 IU/L); albumin ¼ 26.5 g/L (reference range ¼ 40-55 g/L); globulin 43.9 g/L (reference range ¼ 20-40 g/L); total bilirubin 56. 6 Among antiphospholipid antibodies, anti b2-glycoprotein I antibody 34 RU/mL (0-20 RU/mL) and anticardiolipin IgA antibody 24 U/mL (reference range ¼ 0-10 U/mL), while anticardiolipin IgM antibody and anticardiolipin IgG antibody were within normal limits. Anti-nuclear antibody, anti-neutrophil antibody, and thyroid function tests were also within normal limits.…”

The diagnosis of primary central nervous system vasculitis

“…Finally, as mentioned in the first sentence, cerebral vasculitis is a descriptive term, not a disease, and it has always been anticipated that the term ‘primary CNS vasculitis’ would comprise a spectrum of specific disorders. These are now slowly being dissected and described 47–49. Aβ-related angiitis (ABRA) is one such disorder, likely a subtype of cerebral amyloid angiopathy (CAA), wherein intramural amyloid deposits have triggered an antiamyloid inflammatory reaction and so vasculitic change.…”

“…Aβ-related angiitis (ABRA) is one such disorder, likely a subtype of cerebral amyloid angiopathy (CAA), wherein intramural amyloid deposits have triggered an antiamyloid inflammatory reaction and so vasculitic change. Clearly, only biopsy can distinguish ABRA from other forms of primary CNS vasculitis (and from CAA-related inflammation, in which perivascular inflammation is apparent in the context of CAA—again perhaps triggered by amyloid deposition—but without vasculitis); similarly, only biopsy can identify the other recognised forms of the condition 47–49. In addition, though plainly not an argument that should sway the decision in any specific individual case, it is only by looking at tissue that further specific entities will come to be described.…”

A Closer Look at Angiitis of the central nervous system

“…The SACNS is a central nervous system vasculitis caused by known etiologies. Systemic vasculitides and vasculitis associated with some systemic diseases, especially immune abnormalities such as lupus vasculitis, rheumatoid vasculitis, Gougerot Sjögren’s syndrome and idiopathic hypereosinophilic syndrome, 4 , 12 may initiate ACNS. Cancer, certain drugs and infections are also considered to be potential etiologies.…”