What is the role of lab testing in the workup of transient vision loss (TVL)?

Updated: May 21, 2019
  • Author: Andrew J Tatham, MD, MBA, FRCOphth, FEBO, FRCS(Ed); Chief Editor: Andrew G Lee, MD  more...
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Answer

Answer

Patients with transient vision loss (TVL) should undergo a basic laboratory workup. Blood pressure should be checked, in that hypotension is not infrequent cause of visual disturbance. The following blood investigations should be considered in the appropriate clinical setting:

  • Complete blood count (CBC) to check for conditions such as anemia and polycythemia
  • Connective tissue diseases (eg, Wegener granulomatosis)
  • Coagulopathy studies (eg, for antiphospholipid syndrome)
  • Sickle cell test
  • Acute phase reactants in elderly patients suspected of having giant cell arteritis (eg, ESR and CRP)

A hypercoagulable thrombotic state may exist as a consequence of increased activity of procoagulant compounds (eg, prothrombin, factor Va, thrombin, factor VIII, lipoprotein [a], and fibrinogen), decreased levels of anticoagulants (eg, protein C, protein S, and antithrombin III), or decreased levels of fibrinolytic compounds (eg, plasminogen and plasmin).

Hypercoagulability may also be caused by antibodies against membrane phospholipids and plasma proteins (eg, lupus anticoagulant and anticardiolipin antibodies). Young people with transient focal neurologic events, particularly those with monocular visual symptoms and no family history of migraine, may have antiphospholipid antibodies. [37]

Urinalysis should be performed to test for glucose to evaluate for acute hypoglycemia or diabetes.


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