Case Report
A seven-year-old boy presented with history of sudden
onset of severe headache, vomiting and low-grade fever for seven days
associated with increasing diplopia, blurring of vision and photophobia
for three days. There was no history of head injury, physical weakness or
sensory loss. There was no past history of febrile illness with rash
suggestive of varicella. No similar illness was reported in any other
family members.
On examination, he was well oriented and interactive. A
resting tachycardia (heart rate 166/min) and hypertension (116/84 mmHg)
was found. Bilateral ptosis, mydriasis, loss of direct and consensual
reflex and severe limitation of eye movements on all directions were
noted. Fundo-scopy was normal. No other focal neurological deficit was
found. Other systems were normal.
Baseline hematological study was normal. Cerebrospinal
fluid showed a normal cell count with a high protein content (200mg %). An
awake EEG record showed slow background activity suggesting
encephalopathy. A diffuse high signal intensity involving the occipito-parietal
cortical and sub cortical regions were shown in T2 weighted MRI. MR
angiography revealed a diffuse narrowing of right sided internal carotid
artery, bilateral middle cerebral arteries and vertebrobasilar arteries (Fig.1).
Autoantibody screen, serum homocysteine, protein C, protein S,
antithrombin III, antiphospholipid antibody levels were normal. HIV-ELISA
was non reactive.
|
Fig.1 Diffuse narrowing of right internal
carotid and bilateral middle cerebral and vertebrobasilar arteries |
A presumptive diagnosis of primary CNS angiitis was
considered. Treatment was initiated with intravenous dexamethasone given
for one week followed by oral prednisolone (1 mg/kg/day) for four weeks.
Hypertension was treated with oral nifedipine. Major symptomatic
improvement was noted within two weeks and he became asymptomatic by 3rd
week. Prednisolone was tapered and discontinued in another two weeks. MR
angiography two and six months later showed complete resolution of all the
previous lesions and no evidence of any new lesion.
Considering the complete resolution of the
angiographically demonstrated vascular narrowing following a course of
steroid treatment a final diagnosis of benign angiopathy of central
nervous system (BACNS) was made.
Discussion
Diagnostic criteria of primary angiitis of CNS were
proposed in 1988 with clinical description of 46 cases worldwide. These
criteria included (i) an unexplained neurologic deficit despite
aggressive diagnostic evaluation; (ii) a high probability angiogram
for arteritis and/or histopathologic evidence of arteritis confined to the
CNS; and (iii) exclusion of all those disorders capable of
mimicking the angiographic findings or associated with vascular
inflammation of the CNS(1). The clinical presentations are highly variable
but the triad of headache, organic brain syndrome and multifocal
neurodeficit is highly suggestive of the condition. Systemic symptoms are
mostly absent in the affected patients as is laboratory evidence of
inflammation(2).
Blood tests are not helpful in the diagnosis of CNS
vasculitis. Cerebrospinal fluid (CSF) analysis is usually abnormal in
patients with PACNS, showing pleocytosis and elevated protein levels,
though it is usually normal in BACNS. CSF study is also helpful in ruling
out vasculitic mimics(2). The most important diagnostic aid remains the
MRI and MRA. Brain biopsy is considered gold standard for confirming
diagnosis and starting prolonged immunosuppressive therapy in this
condition(3). MRA findings include vascular beading and absence or cut off
of one or more vessels seen in single or multiple vascular beds.
Reversibility of angio-graphic abnormalities is essential for diagnosis of
BACNS. Reduced sensitivity for smaller caliber vessels remains the major
drawback of angio-graphy(4).
BACNS is treated with tapering course of oral
prednisolone and nifedipine for about 6 months which results in complete
radiological recovery and appearance of no new lesions. On the contrary,
PACNS cases usually need prolonged treatment with cyclophosphamide,
methotrexate, azathioprine and prednisolone along with several MR imaging
for monitoring of activity(5).
1. Calabrese LH, Malek JA. Primary angiitis of the
central nervous system. Report of eight new cases, review of the
literature and proposal for diagnostic criteria. Medicine 1994; 67: 20-40.
2. Calabrese LH. Vasculitis of the central nervous
system. Rheum Dis Clin North Am 1995; 21: 1059-1076.
3. Calabrese LH, Furlan AJ, Gragg LA, Ropos TJ. Primary
angiitis of the central nervous system: diagnostic criteria and clinical
approach. Cleve Clin J Med 1992; 59: 293-306.
4. Duna GF, Calabrese LH. Limitations of invasive
modalities in the diagnosis of primary angiitis of the central nervous
system. J Rheumatol 1995; 22: 662-667.
5. Hajj-Ali RA, Furlan A, Abou-Chebel A, Calabrese LH.
Benign angiopathy of the central nervous system: cohort of 16 patients
with clinical course and long-term follow up. Arthritis Rheum 2002; 47:
662-669.