Ecase #15

Melissa Chen, M.D.

July 22-26, 2002

A 82-year-old woman presents to your clinic with daily bitemporal headaches but is otherwise well.  Her physical exam is unremarkable, and her ESR is moderately elevated at 70.   What additional history and physical exam findings suggest possible temporal arteritis?

Discussion

The average age of onset of TA is 72 years.   It virtually never occurs before the age of 50 years, and the annual incidence rises steadily thereafter. To be classified as having TA, the patient must meet 3 of 5 criteria:

1. Age >50 

2. new onset localized headache

3. temporal artery tenderness or decreased  pulse

4. ESR >50

5. abnormal temp artery biopsy findings demonstrating mononuclear infiltration or granulomatous inflammation.

These criteria do have limitations; some studies have shown that these criteria have a PPV of only 29%.

The only 2 historical features that substantially increased the likelihood of TA among patients referred for biopsy were jaw claudication (positive LR [likelihood ratio] 4.2) and diplopia (LR 3.4).   The absence of any temporal artery abnormality was the only clinical factor that modestly reduced the likelihood of disease (negative LR 0.53).  Predictive physical findings included temporal artery beading (LR 4.6), prominence (LR 4.3) and tenderness (LR 2.6).  Normal ESR indicated much less likelihood of disease (negative LR 0.2).  The absence of any historical element did not rule out TA or make the disorder substantially less likely.

The headache in TA (occurs in 77%) is a new headache that is either recent in onset or different from previous headaches.  Though often nonspecific in character, it is typically severe and throbbing, less often sharp/dull/burning, and is bitemporal in half of cases.  Headache may actually be due to scalp tenderness, reported as pain when combing hair or putting on a hat.

Jaw claudication (51%) refers to pain in the proximal jaw near the TMJ that develops only after a brief period of chewing, especially food requiring vigorous mastication.  It is essentially angina of the muscles of mastication.  However, only half the patients with jaw pain from TA provide a classic description;  many report only a vague discomfort in or around the jaw that may be unrelated to chewing, and some even present with sinus or ear pain.

Visual symptoms (29%) commonly include sudden monocular blindness, but may also include stuttering onset, amaurosis fugax, a field cut, or diplopia.PMR (34%) is an inflammatory polyarthritis with tendon or bursal involvement, typically causing abrupt onset of morning stiffness involving the neck, shoulders, and hips with referred pain to the proximal arms and thighs.

PMR occurs in 50% of those with TA;  TA occurs in 15% of those with PMR.  Presence of actual synovitis, however, makes positive biopsy results significantly less likely.Malaise, fever, and weight loss can be caused by cytokine release.  Fever (in up to 50%) is usually low grade, but can reach 39-40°C.

Physical exam is frequently unremarkable, but certain abnormalities may increase suspicion of disease.  Light palpation just anterior and slightly superior to the tragus of the ear may detect tenderness, reduced or absent pulsation, erythema, nodularity, or swelling.  The scalp and tongue should be inspected for ischemic or necrotic skin changes.    Check the carotid and subclavian arteries for bruits.

CRP is preferred to ESR when there are abnormalities of serum proteins that can false elevated ESR, such as a monoclonal gammopathy or the hypergammaglobulinemia associated with liver disease.    It also changes more rapidly with therapy. Diagnosis is facilitated by obtaining large biopsy specimens (>2cm long) because skip lesions are believed to occur.  Bilateral biopsies are usually not needed because they are concordant in 95-99% of cases.  Temporal artery Doppler/ultrasound is starting to be used - the "halo sign" is specific but not sensitive.

Steroids substantially reduce the incidence of visual loss.  Even among patients with complete unilateral visual loss, prompt treatment will decrease the risk of visual loss in the contralateral eye.  Empiric treatment should be started either immediately or immediately after an ESR is drawn.   Steroid treatment for less than 2 weeks does not alter biopsy yield.   Observational data suggests a better prognosis for those with visual loss if IV steroids are given.  For most patients, the effective starting dose is 40-60mg PO qd prednisone, which should be continued until all reversible symptoms and findings have disappeared, and lab tests have reverted to normal - usually 2-4 weeks.  If resistant, the diagnosis should be reevaluated.  Long duration is often required (often >2 years).  Methotrexate has been used as a steroid-sparing agent but has not always been successful.

References

Hellman, DB.  Temporal Arteritis.  JAMA 12 June 2002  287(22):  2996-3000.

Smetana, GW and RH Schmerling.  Does this patient have temporal arteritis?  JAMA 2 January 2002 2871(1): 92-101.