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Cranial Arteritis
(Temporal / Giant Cell Arteritis)
What is Cranial Arteritis / Giant Cell Arteritis / Temporal
Arteritis
/ Horton's Disease?

Giant Cell Arteritis (GCA) is an inflammatory disease of
the head).  It is a form of
vasculitis.  The inflammation
causes the arteries to become narrow, restricting blood
flow in the head.  It is a serious disease that varies in
severity but can often be treated successfully.

The exact cause of
GCA is unknown, but it is thought to be
an
auto-immune reaction (one in which the immune system
reacts inappropriately) in the lining of the arteries.

The name,
Giant Cell Arteritis, reflects the type of
inflammatory cell that is involved (as seen on biopsy).

The name,
Temporal Arteritis, indicates that the Temporal
Artery
, which runs over the temple near the ear, is
affected.  Other arteries such as the
Aorta, may be
affected, especially those that supply the head and eyes.  


What are the signs & symptoms?

Physical Exam

  • Palpation of the head reveals prominent temporal
    arteries with or without pulsation.
  • The temporal area may be tender.
  • Decreased pulses may be found throughout the body.
  • Evidence of ischemia may be noted on fundal exam.
Laboratory Tests

  • Erythrocyte Sedimentation Rate (ESR), an
    inflammatory marker, > 60 mm / hour (normal 10 - 40
    mm / hour), but may be normal in approximately 20%
    of cases.
  • C-reactive protein, another inflammatory marker, is
    also commonly elevated.
  • Platelets may also be elevated.


Investigations

Biopsy.  The gold standard for diagnosing GCA is biopsy,
which involves removing a small part of the vessel and
examining it microscopically for
giant cells infiltrating the
tissue.  Since the blood vessels are involved in a patchy
pattern, there may be unaffected areas on the vessel and
the biopsy might have been taken from these parts.  
Unilateral biopsy of a 1.5 - 3 cm length is 85 - 90%
sensitive.  So, a negative result does not definitely rule out
the diagnosis.

Imaging studies.  Radiological examination of the temporal
artery
with ultrasound yields a halo sign.  Contrast
enhanced brain
MRI and CT is generally negative in this
disorder.  Recent studies have shown that
3T MRI using
super high resolution imaging and contrast injection can non-
invasively diagnose this disorder with high specificity and
sensitivity.

GCA - Key Features

  • Women, usually over 55 years, predominantly affected
  • Weakness, low-grade fever and weight-loss often
    early features
  • Severe throbbing headache is a major symptom
  • The Temporal Artery frequently becomes red, tender,
    firm, swollen and tortuous
  • Ischæmic pain in the masticatory muscles prominent
    in 20%.  Pain on mastication (chewing), comparable to
    and often misnamed, jaw claudication (claudication is
    literally, limping), is sometimes the main symptom and
    present in about 20% of patients.
  • ESR usually greatly raised
  • Disturbances of vision or sudden blindness due to
    involvement of the ophthalmic artery develops in 50%
    of untreated patients.
  • Good response to early treatment with corticosteroids
  • Polymyalgia rheumatica, with weakness and pain of
    the shoulder or pelvic girdles and fever may be
    associated.



What are the causes of Cranial Arteritis / Giant Cell
Arteritis
?

Inflammation involves the arterial media and intima (layers
within the blood vessel wall).  Infiltration by
mononuclear
cells
is typically associated with giant cells (immune and
inflammatory cells).  
Intimal damage leads to formation of
thrombi (blood clots), which usually become organised and
there may be severe damage to the
internal elastic
lamina
, sometimes going on to complete destruction.  
Healing is by
fibrosis (scarring), particularly of the media,
thickening of the
intima, and partial re-canalisation of the
thrombus (blood clot).

The risk of blindness makes it essential to start treatment
early.  Systemic
corticosteroids (starting with 60 mg/day)
should be given on the basis of inflamed scalp vessels and
a high (> 60 mm / h)
ESR.  Corticosteroids are usually
quickly effective and should be continued until the
ESR falls
to normal

Lesions skip short lengths of an artery and a biopsy should
be at least 3 cm long.

Corticosteroids, typically high-dose prednisone (40 – 60
mg BD), must be started as soon as the diagnosis is
suspected (even before the diagnosis is confirmed by
biopsy) to prevent irreversible blindness secondary to
ophthalmic artery occlusion (blockage).

Steroids do not prevent the diagnosis from later being
confirmed by biopsy, although certain changes in the
histology may be observed towards the end of the first
week of treatment and are more difficult to identify after a
couple of months.

The dose of steroid, such as
prednisone is lowered after 2
– 4 weeks and slowly tapered over the course of 9 – 12
months.  Oral steroids are at least as effective as
intravenous steroids, except in the treatment of acute visual
loss where intravenous steroids appear to offer significant
benefit over oral steroids.


Useful Websites:

Dept of Ophthalmology & Visual Sciences, University of
Iowa Healthcare

Wikipedia

Emedicine (Dermatology)

Emedicine (Radiology)

Emedicine (Emergency Medicine)

Emedicine (Neurology)

Emedicine (Pathology)

Emedicine (Rheumatology)

Emedicine (Temporal Artery Biopsy, Clinical Procedure)

American Academy of Family Physicians

Mayo Clinic

Net Doctor

NHS Clinical Knowledge Summaries


Useful Articles:

Ottawa Head Ache Clinic.  Temporal Arteritis.

J American Medical Association 2002.  Temporal Arteritis.

MJA 2002.  Lessons from Practice - Lingual Arteritis In An
Elderly Woman.

Orphanet Encyclopædia 2003.  Giant Cell Arteritis.

J Chin Med Assoc 2005.  Temporal Arteritis.

OT 2005.  Giant Cell Arteritis - Emphasis on the Temporal
Artery Biopsy.

JCDA 2008.  Point of Care.  Question 1.  What is the Rôle
of the Dentist in the Early Diagnosis of Temporal Arteritis.

EULAR Recommendations for the Management of Large
Vessel Vasculitis 2008.
Last Updated 18th August 2010