Uveitis or Iritis of Unknown Etiology: Inflammation in the eye for unknown reasons


Uveitis or Iritis of Unknown Etiology: Inflammation in the eye for unknown reasons



Uveitis is inflammation of the uveal tract, which is further subdivided into anterior (front) and posterior (back part of eye) components. 


The anterior tract is composed of the iris and ciliary body. Inflammation of the iris is called iritis.
The posterior tract includes choroid. 


Uveitis is inflammation of any of these components and may also include other surrounding tissues such as sclera, retina, and optic nerve.


Uveitis can be due to many causes.


The most common is idiopathic, which means, all blood test are normal and we do not know why the inflammation is there. 
Other causes are:
1. Trauma
2. Autoimmune Disease or immune reaction: (ie from Rheumatoid Arthritis, Inflammatory Bowel Disease, Crohn’s)
3. Infections: from virus, bacteria
4. Cancer


The red coloring below represents the uveal tract. 





First episode of non-granulomatous iritis (a type of iritis or eye inflammation and the most common) usually does not require an extensive work up. If there are no other finding on a general physical examination, we follow the patient to see if another episode occurs. 

However, if there is any risk of Lyme, Herpes disease, we would recommend a baseline Lyme, Herpes titers. 

If iritis (or uveitis) recurrs multiple times, the standard of care for blood tests are as follows: 

1. CBC, 

2. ESR, 

3. CRP, 

4. HLA-B27

5. RPR, 

6. FTA-ABS, 

7. ACE level, 

8. Lyme titer, 

9. Toxoplasmosis titer, 

10. PPD, 

11. urinalysis, 

12. Chest X-ray, 

13. HIV. 

If the patient has diarrhea or a history of Inflammatory Bowel Disease (Crohn’s Disease or Ulcerative Colitis), we will recommend: 

14. test for anti-Saccharomyces cerevisiae antibodies (ASCA): more common in Crohn disease 


15. perinuclear anti-neutrophil cytoplasmic antibody (pANCA):more common in Ulcerative Colitis 

Studies have shown a nonspecific approach to laboratory work-up in the initial diagnosis of iritis/uveitis is both inefficient and cost-intensive. Thus a focused history and examination would determine which labs tests are most appropriate so we do not order 15 labs.


For patients who we suspect of having Inflammatory Bowel Disease:




How is it used?

The test for anti-Saccharomyces cerevisiae antibodies (ASCA) is used to help distinguish between Crohn disease (CD) and ulcerative colitis (UC), the two most common types of inflammatory bowel disease (IBD). Testing usually includes detecting two different classes of ASCA in the blood, IgG and IgA.
ASCA are immune proteins that are frequently present in people who have IBD. The association between the presence of ASCA and their involvement in the disease process, however, is not understood at this time.
IBDs are primarily diagnosed through non-laboratory evaluations, such as a biopsy of the intestine. In some cases, however, it can be difficult to distinguish between CD and UC. An ASCA test is often ordered along with a test for perinuclear anti-neutrophil cytoplasmic antibody (pANCA) to help determine which type of IBD a person has. The presence of ASCA is more common in CD, while pANCA is more common in UC. Anti-CBir1 (anti-flagellin antibody) and anti-Omp C (anti-outer membrane protein antibody) are indicative of CD and may also be used in combination with ASCA testing.
Since the symptoms associated with IBD may be seen with a number of conditions, other tests are frequently performed prior to or along with ASCA testing to rule out other causes for the symptoms. For more on this, see the article onInflammatory Bowel Disease.
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When is it ordered?

ASCA testing is primarily ordered when a person has signs and symptoms that suggest IBD and a healthcare practitioner is attempting to distinguish between CD and UC. It may be ordered along with pANCA and other antibody testing.
Signs and symptoms of an IBD may include:
  • Abdominal pain and cramps
  • Diarrhea
  • Rectal bleeding
  • Fever
  • Fatigue
  • In some people, joint, skin, bone and organ-related symptoms
  • Children may also have delayed development and growth retardation.
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What does the test result mean?

A positive ASCA result is not diagnostic of CD, UC, or of an IBD, but it does make it more likely that a person with symptoms has an IBD.
Results of ASCA testing are often interpreted in conjunction with the results of pANCA testing:
  • If ASCA is positive and pANCA is negative, then it is likely that the person has CD.
  • If ASCA is negative and pANCA is positive, then it is likely that the person has UC.
A negative result for ASCA and pANCA does necessarily rule out IBD. A person who is negative may still have CD, UC, or another IBD.
The presence of multiple antibodies (ASCA, anti-CBir1, anti-Omp C) may indicate the likelihood of a more aggressive disease, but negative results do not rule out aggressive disease.
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Is there anything else I should know?

There are many other antibody biomarkers that are associated with IBD.
The amount of ASCA and/or pANCA present does not correlate with the severity of a person’s symptoms or condition and it cannot be used to monitor response to treatment
https://labtestsonline.org/understanding/analytes/asca/tab/test/
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