Teaching NeuroImage: Microangiopathic complications in pseudoxanthoma elasticum

Cerebral microbleeds: a magnetic resonance imaging review of common and less common causes

Cerebral microbleeds (CMBs) are small foci of (acute, subacute or chronic) blood products, best seen using magnetic resonance imaging (MRI) techniques sensitive to iron deposits (i.e. gradient-echo T2*-weighted and susceptibility-weighted imaging), frequently encountered in small vessel disease (SVD) (with hypertensive vasculopathy and cerebral amyloid angiopathy as the most frequent conditions) and also in other disorders. In this review, the MRI characteristics of CMBs and the associated MRI abnormalities encountered in common and less common SVD and non-SVD conditions are the main focus. Identification of the origin of CMBs depends on their localization, the presence of other associated MRI abnormalities, and the patient's history and clinical state.

Neurologic manifestations of inherited disorders of connective tissue

Inherited disorders of connective tissue are single gene disorders affecting structure or function of the connective tissue. Neurological manifestations are classic and potentially severe complications of many such disorders. The most common neurological manifestations are cerebrovascular. Ischemic stroke is a classic complication of vascular Ehlers-Danlos syndrome (type IV), homocystinuria, and arterial tortuosity syndrome, and may occasionally be seen in Marfan syndrome and pseudoxanthoma elasticum with distinct underlying mechanisms for each disease. Vascular Ehlers-Danlos syndrome can also lead to cervical artery dissection (with or without ischemic stroke), carotid-cavernous fistula, intracranial dissections and aneurysms potentially causing subarachnoid or intracerebral hemorrhage, and arterial rupture. Other neurological manifestations include nerve root compression and intracranial hypotension due to dural ectasia in Marfan and Loeys-Dietz syndrome, spinal cord compression in osteogenesis imperfecta, and mucopolysaccharidosis type I and VI, carpal tunnel syndrome in mucopolysaccharidosis type I, II, and VI. Impaired mental development can be observed in homocystinuria, mucopolysaccharidosis type II, and the severe form of mucopolysaccharidosis type I. For the neurologist, being aware of these complications and of the diagnostic criteria for inherited connective tissue disorders is important since neurological complications can be the first manifestation of the disease and because caution may be warranted for the management of these patients.