Thursday 4 August 2011

Systemic lupus erythematosus (SLE) MRI Brain

A 28 yo female under psychiatric treatment for confusional state and altered cognition.
Previous CT report mentions cerebral cortical atrophy. 
MRI Brain FLAIR with non contrast 3D TOF MR Angiography of Brain and Neck shows:
Diffuse cerebral cortical atrophy - mild but significant for age.
A chronic infarct involving right medial temporal lobe - right cortical PCA territory.
A small right parietal cortical infarct.
Multiple chronic lacunes and lacunar infarcts.
No significant major vessel stenosis or occlusion on MR Angio.

Possibilities suggested in this case were SLE, Anti phospholipid Antibody syndrome.
Considering young female pt with psychiatric history goes in favor of SLE.
Patient responding well to Steroids and immuno suppressants.

Systemic lupus erythematosus
Syn: Neuropsychiatric SLE (NP SLE)

An autoimmune disorder that affects many organ systems, including CNS.

MRI is the investigation of choice.
Imaging wise diagnostic clue is age significant atrophy cerebral cortical atrophy with multi focal cortical infarcts, chronic lacunes and lacunar infarcts in white matter.

Angiographies as well as Venography both are needed in addition. In SLE, CT or MR Angiography often normal. May be abnormal, may show thrombotic occlusion of intra cranial vessels or thrombosed dural venous sinuses especially in cases of antiphospholipid syndrome.

Imaging wise DDs
- Antiphospholipid antibodies (non-SLE).
- Small vessel disease.
- Microangiopathy, Vasculitides Primary angiitis of CNS, Polyarteritis nodosa, Wegener, Behcet disease, Syphilis, Sjogren syndrome.

Pathogenesis of NP SLE is likely multi factorial.
Genetic predisposition is known; HLA-DR2, HLA-DR3, null complement alleles, congenital deficiencies of complement C4, C2.
Neuronal dysfunction mediated by anti-neuronal, anti-ribosomal, P-protein and anti-cytokines antibodies.
Circulating immune complexes leading to vascular injury.
Endothelial cell activation by cytokines and complement activation leading to occlusive vasculopathy.
Antiphospholipid antibodies (APL-Ab) lead to macro and micro vascular thrombosis.

All age groups affected; peak incidence in young 20-45 years with strong female predominance as high as 5:1
NP SLE is due to CNS involvement, seen in up to 75% of cases of SLE
Most common signs and symptoms include migraine, seizures, stroke, chorea. Psychosis, mood disorders, acute confusional state, cognitive dysfunction are common.
Transient neurologic deficits.
Rarely Transverse myelopathy, cranial neuropathies, aseptic meningitis.

Neurological complications worsen prognosis of SLE
Mortality rate in NP SLE is 7-40%

Immunosuppressive agents like steroids, cyclophosphamide for Vasculitis.
Lifelong anticoagulation for APL-Ab-mediated thromboembolic events.
Intrathecal methotrexate and dexamethasone for severe cases.
Prophylactic Aspirin, lipid-lowering drugs.

Reference: Osborn Diagnostic Imaging.

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