Differential Diagnosis in Neurology

16.12. Vasculitic and Microangiopathic Forms of Dementia

• General considerations:
  • Deficits occur in:
    • Cranial nerves
    • Peripheral nerves
    • Spinal cord
    • Large or small vessel stroke
  • Rarer presentation:
    • Depressed consciousness
    • Confusional states
    • Dementia

SLE

• General considerations:
  • Dementia occurs often with acute exacerbations and increased disease activity
• Clinical features:
  • Large and small cerebral infarcts lead to multi-infarct dementia:
    • Lupus anticoagulant, anticardiolipin antibodies (ACL antibodies are present)
    • Spontaneous thrombosis of large and small vessels
    • Stroke syndrome of young adults
  • Associated findings:
    • Livedo reticularis (ACL antibodies)
    • Libman–Sachs endocarditis (verrucous subvalvular fibrin deposits with emboli)
    • History of thrombotic events and abortion is common
• Laboratory evaluation:
  • Prolonged PTT, false positive syphilis serology, thrombocytopenia suggest ACL antibody state
• Pathology:
  • Vasculitis (neutrophils invading cerebral) 85%
  • CSF:
    • Increased protein, lymphocytes and IgG
    • Decreased complement
    • Imaging:
      • SPECT may show defects > MRI

Polyarteritis Nodosa

• General considerations:
  • Peripheral nerve or plexus lesions (40–60%)
  • CNS involvement:
    • 20–40% of patients
    • Involvement of large intra and extracranial vessels, intracranial arterioles
• Clinical features:
  • Multifocal deficits
  • Global encephalopathy
  • Dementia
  • Seizures
  • Large vessel stroke
  • Stupor and coma
• Pathology:
  • Necrotizing vasculitis of small and medium sized muscular arteries
  • Segmental lesions
  • Endothelial proliferation
  • Polymorphonuclear and mononuclear cell infiltration of blood vessels
  • Kidneys involved with consequent HCVD

Isolated Vasculitis of the Central Nervous System (Primary Granulomatous Angitis)

• General considerations:
  • Involvement of arterioles primarily
  • Occasional involvement of large intracranial vessels
  • No systemic signs of vasculitis
• Clinical features:
  • Affects adults in fifth to eight decade
  • Cognitive decline (subacutely)
  • Seizures
  • Focal neurological signs
  • Headache
  • Impaired consciousness
  • Cranial neuropathy (rare)
  • Spinal cord infarction (rare)
• Laboratory evaluation:
  • Normal sed rate
  • Mild pleocytosis and elevated CSF protein
  • Angiographic demonstration of vasculitis:
    • Segmental narrowing of tertiary blood vessels

Giant Cell Arteritis

• General considerations:
  • Extracranial blood vessels
  • Sed rate usually between 80–120 mm³
• Clinical features:
  • Severe headache (burning scalp)
  • Blindness (infarction of the posterior ciliary arteries that form watershed with the CRA at the optic disc)
  • Rarely involvement of carotid, vertebral arteries, and arch of the aorta
  • Brainstem and cerebellar involvement
  • Vascular dementia
• Laboratory evaluation:
  • Sed rate elevated

Thrombotic Thrombocytopenic Purpura (TTP)

• General considerations:
  • Antibody attack on platelets
  • Naked thrombocytes in the bone marrow
• Clinical features:
  • Acute confusional state
  • Psychosis
  • Seizures
  • Renal failure
  • Purpuric skin lesions
  • Rare vascular dementia
• Pathology:
  • Granular atrophy of the cerebral cortex
  • Fibrotic cortical vessels
  • Organized thrombi
• Differential Diagnosis of TTP:
  • Cerebral form of thromboangiitis obliterans

Central Nervous System Angioendotheliosis

• General characteristics:
  • Malignant lymphoma of blood vessels
  • Affects dural blood vessels
• Clinical features:
  • Subacute dementia over months
  • Skin ulcerations
  • Renal failure
• Pathology:
  • Proliferation of endothelial cells in many organs
  • No inflammation
  • Occlusion of small vessels with secondary thrombosis
  • Ischemic necrosis of the cerebral cortex