Second edition

10.qxd 3/10/08 5:52 PM Page 438
438 Vascular disorders
example to the posterior cerebral artery. It also appears that
small branches of the vertebral arteries may also be
occluded, leading to medullary infarction. With involvement
of the internal carotid artery, clots may also form, with
embolization downstream to cause occlusion of the middle
or anterior cerebral arteries or their branches. It is debated
whether (or with what frequency) smaller arteries in the
anterior circulation become inflamed; however, one report
suggested that small penetrating arteries may be involved,
causing multiple lacunes. In some cases, if the number and
location of infarctions is appropriate, either a multi-infarct
dementia (Caselli 1990) or a lacunar dementia (Nightingale
et al. 1982) may ensue.
Most cases of cranial arteritis are further characterized
by constitutional symptoms, such as malaise, fatigue,
anorexia, and a low-grade fever, and most patients will also
have an associated polymyalgia rheumatica, with muscle
aching and stiffness, which, although diffuse, is most
prominent in the neck and shoulders.
With rare exceptions (Kansu et al. 1977) the erythrocyte
sedimentation rate (ESR) is elevated, generally above
50 mm/min (Westergen) and often above 100 mm/min.
Mild anemia is common and the alkaline phosphatase may
also be elevated. The diagnosis is confirmed by biopsy of an
involved artery, such as the temporal artery; given the segmental
nature of the inflammation, however, false negatives
are possible and multiple biopsies may be required.
Course
The inflammatory process generally undergoes a gradual,
spontaneous remission in anywhere from several months
to several years.
Etiology
Involved arteries show a graulomatous inflammation characterized
by the presence of giant cells. As noted, the
inflammation is segmental, and between the involved segments
the artery may be normal. Thrombi may form over
the inflamed areas and, as noted earlier, emboli may be
generated (Wilkinson and Russell 1972); in some cases the
artery may become occluded. Although the mechanism
underlying the inflammation is not known, an autoimmune
process is suspected.
Differential diagnosis
The diagnosis should be suspected in cases of amaurosis
fugax, blindness, or stroke, occurring in the setting of
headache, constitutional symptoms, polymyalgia rheumatica,
or an elevated ESR. Systemic lupus erythematosus may
be considered in the differential, but here the anti-nuclear
antibody (ANA) test is positive. Polyarteritis nodosa may
also be suspected; however, here, renal or gastrointestinal
involvement will indicate the correct diagnosis.
Treatment
Urgent treatment with steroids is essential to prevent stroke
or blindness. Traditionally, prednisone is used, starting at
doses of approximately 60 mg/day and, once symptoms are
controlled and the ESR has dropped, tapering the dose
gradually to the minimum required to keep the patient
asymptomatic and the ESR down. Recent work suggests
that aggressive treatment with methylprednisolone at
15 mg/kg (of ideal body weight) daily for the first 3 days,
followed by prednisone, induces a more rapid remission
and ensures a more favorable course (Mazlumzadeh et al.
2006). Uncontrolled work further suggests that use of lowdose
aspirin concurrent with prednisone may also reduce
the risk of stroke (Nesher et al. 2004).
10.6 CEREBRAL AMYLOID ANGIOPATHY
Cerebral amyloid angiopathy, also known as congophilic
amyloid angiopathy, is a not uncommon disorder characterized
by an amyloid angiopathy that may lead to spontaneous
lobar intracerebral hemorrhages, a gradually
progressive dementia secondary to a widespread leukoencephalopathy,
or a combination of these findings; cerebral
‘microhemorrhages’ commonly accompany these findings.
Clinical findings
Cerebral amyloid angiopathy typically has an onset in the
seventh or later decades, and may present with either spontaneous
lobar intracerebral hemorrhages or with a gradually
progressive dementia (Cosgrove et al. 1985; Gilles et al.
1984; Haan et al. 1990a; Nobuyoshi et al. 1984; Yoshimura
et al. 1992).
The lobar intracerebral hemorrhages present with a
gradual evolution, over perhaps a half-hour, of headache,
nausea and vomiting, and a focal deficit appropriate to the
location of the hemorrhage. Classically, the hemorrhage
occurs spontaneously and recurrences are the rule. With
multiple recurrences, a ‘stepwise’ accrual of cognitive
deficits may occur, eventually leading to a picture of multiinfarct
dementia.
Dementia, as noted, may also be of gradual onset and
progression, and in this instance it is non-specific in character,
with decreased short-term memory, variable disorientation,
and deficits in abstracting and calculating ability.
Cerebral microhemorrhages may occur, and these may
be silent or may present with relatively minor focal findings
that, in most cases, resolve over time (Greenberg et al.
1993). Residual deposits of hemosiderin may serve as
seizure foci, and partial seizures may also occur.