Title: Sudden acquired retinal degeneration syndrome

{{Short description|Disease of dogs}}
'''Sudden acquired retinal degeneration syndrome''' ('''SARDS''') is a disease in [[dog]]s causing sudden blindness.  It can occur in any breed, but female dogs may be predisposed.&lt;ref&gt;{{cite journal |vauthors=Cullen C, Grahn B |title=DIAGNOSTIC OPHTHALMOLOGY: What are your clinical diagnosis, lesion localization, and differential diagnoses? |journal=Can Vet J |volume=43 |issue=9 |pages=729–30 |year=2002 |pmid=12240536 |pmc=339566}}&lt;/ref&gt;  Approximately 4000 cases are seen in the [[United States]] annually.&lt;ref name=DVM_July&gt;{{cite journal | title = Some blind dogs may get chance to see again | journal = DVM | pages = 1S | publisher = Advanstar Communications |date=July 2007 }}&lt;/ref&gt;

==Characteristics==

Symptoms include sudden permanent blindness, but may occur more slowly over several days, weeks or months,&lt;ref&gt;{{cite web | title = Sudden Acquired Retinal Degeneration (SARD) | work = The Merck Veterinary Manual | year = 2006 | url = http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/160611.htm| accessdate = 2007-03-11 }}&lt;/ref&gt; dilated [[pupil]]s. Pupillary light reflexes  are usually reduced but present; the slow phase mediated by [[melanopsin]] in [[retinal ganglion cell]]s is retained. Other symptoms commonly seen are similar to those seen with [[Cushing's disease]] and include increased water consumption and urination, weight gain, confusion, restlessness, behavioral changes and lethargy. These symptoms may develop over a few months preceding the onset of SARDS.&lt;ref&gt;{{cite web | last = Ofri | first = Ron | title = Examination of the Blind Animal | work = Proceedings of the 31st World Congress of the World Small Animal Veterinary Association | year = 2006 | url = http://www.ivis.org/proceedings/wsava/2006/lecture21/Ofri2.pdf?LA=1 | accessdate = 2007-03-11 }}&lt;/ref&gt; Clinical signs and disease progression vary markedly among individual animals, depending on the number and type of hormones that are increased, the degree of hormone elevation, and the age of the dog.&lt;ref name=&quot;Carter RT 2003&quot;&gt;Carter RT, Bentley E, Oliver JW, et al.: Elevations in adrenal sex hormones in canine sudden acquired retinal degeneration syndrome (SARDS) [abstract]. Proc Am Coll Vet Ophthalmol:9:40, 2003.&lt;/ref&gt;

Some owners notice a more obvious &quot;eye shine&quot; in photographs due to the dilated pupils and retinal atrophy creating what is described as a &quot;hyper-reflective tapetum&quot;.{{cn|date=October 2025}}

==Causes==

The cause of SARDS is considered to be [[idiopathic]] and the veterinary community is divided as to its cause, but the most common hypotheses on the causes of the disease possibly include [[autoimmune disease]], or exposure to toxins. Autoimmune disease as a cause is controversial because some studies have supported the presence of antiretinal [[autoantibody|autoantibodies]] in dogs with SARDS,&lt;ref&gt;{{Cite journal|last1=Braus|first1=Barbara K.|last2=Hauck|first2=Stefanie M.|last3=Amann|first3=Barbara|last4=Heinrich|first4=Christine|last5=Fritsche|first5=Jens|last6=Köstlin|first6=Roberto|last7=Deeg|first7=Cornelia A.|date=July 2008|title=Neuron-specific enolase antibodies in patients with sudden acquired retinal degeneration syndrome|journal=Veterinary Immunology and Immunopathology|volume=124|issue=1–2|pages=177–183|doi=10.1016/j.vetimm.2008.02.020|pmid=18405980}}&lt;/ref&gt;&lt;ref&gt;{{Cite journal|last1=Bellhorn|first1=R. W.|last2=Murphy|first2=C. J.|last3=Thirkill|first3=C. E.|date=February 1988|title=Anti-retinal immunoglobulins in canine ocular diseases|journal=Seminars in Veterinary Medicine and Surgery (Small Animal)|volume=3|issue=1|pages=28–32|issn=0882-0511|pmid=3363244}}&lt;/ref&gt; but others have failed to show a link.&lt;ref&gt;{{cite journal|vauthors=Keller R, Kania S, Hendrix D, Ward D, Abrams K|year=2006|title=Evaluation of canine serum for the presence of antiretinal autoantibodies in sudden acquired retinal degeneration syndrome|journal=Veterinary Ophthalmology|volume=9|issue=3|pages=195–200|doi=10.1111/j.1463-5224.2006.00466.x|pmid=16634935}}&lt;/ref&gt; Despite similar symptoms and blood test results to Cushing's disease, evaluation of dogs with SARDS did not reveal any tumors in the [[pituitary gland|pituitary]] or [[adrenal gland]]s,&lt;ref&gt;{{cite journal |vauthors=Gilmour M, Cardenas M, Blaik M, Bahr R, McGinnis J |title=Evaluation of a comparative pathogenesis between cancer-associated retinopathy in humans and sudden acquired retinal degeneration syndrome in dogs via diagnostic imaging and western blot analysis |journal=Am J Vet Res |volume=67 |issue=5 |pages=877–81 |year=2006 |pmid=16649924 |doi=10.2460/ajvr.67.5.877|doi-access=free }}&lt;/ref&gt; and recent work has indicated significant differences in the clinical and laboratory test parameters between the two diseases.&lt;ref&gt;{{Cite journal|last1=Oh|first1=Annie|last2=Foster|first2=Melanie L.|last3=Williams|first3=Jonathan G.|last4=Zheng|first4=Chaowen|last5=Ru|first5=Hongyu|last6=Lunn|first6=Katharine F.|last7=Mowat|first7=Freya M.|date=2019-03-12|title=Diagnostic utility of clinical and laboratory test parameters for differentiating between sudden acquired retinal degeneration syndrome and pituitary-dependent hyperadrenocorticism in dogs|journal=Veterinary Ophthalmology|volume=22 |issue=6 |pages=842–858 |doi=10.1111/vop.12661|pmid=30864251|s2cid=76666023 }}&lt;/ref&gt;

==Diagnosis==

Examination with an [[ophthalmoscope]] will initially show no changes, but in a few months [[atrophy]] of the [[retina]] will resemble the appearance of [[progressive retinal atrophy]].  [[Pathology|Pathologically]], there is a loss of the [[rod cell|rod]] and [[cone cell]]s followed by degeneration of other layers of the retina.  The retinal degeneration appears to be related to [[apoptosis]] of these cells.&lt;ref&gt;{{cite journal |vauthors=Miller P, Galbreath E, Kehren J, Steinberg H, Dubielzig R |title=Photoreceptor cell death by apoptosis in dogs with sudden acquired retinal degeneration syndrome |journal=Am J Vet Res |volume=59 |issue=2 |pages=149–52 |year=1998 |pmid=9492927}}&lt;/ref&gt;  SARDS must be distinguished from other causes of sudden blindness that have no visible pathology, including retrobulbar [[optic neuritis]], a tumor at the [[optic chiasm]], or other [[central nervous system]] diseases.  [[Electroretinography]] is useful to definitively diagnose SARDS.&lt;ref&gt;{{cite web | last = Gilger | first = Brian C. | title = Diagnosis and Treatment of Ocular Fundus Disorders of Geriatric Dogs | work = Proceedings of the North American Veterinary Conference | year = 2006 | url = http://www.ivis.org/proceedings/navc/2006/SAE/305.pdf?LA=1 | format = PDF | accessdate = 2007-03-11 | url-status = dead | archiveurl = https://web.archive.org/web/20070929110028/http://www.ivis.org/proceedings/navc/2006/SAE/305.pdf?LA=1 | archivedate = 2007-09-29 }}&lt;/ref&gt;

==Treatment==

While there is no unilateral treatment for SARDS&lt;ref name=&quot;Komáromy 2016&quot;&gt;{{cite journal|last1=Komáromy|first1=AM|last2=Abrams|first2=KL|last3=Heckenlively|first3=JR|last4=Lundy|first4=SK|last5=Maggs|first5=DJ|last6=Leeth|first6=CM|last7=MohanKumar|first7=PS|last8=Petersen-Jones|first8=SM|last9=Serreze|first9=DV|last10=van der Woerdt|first10=A|title=Sudden acquired retinal degeneration syndrome (SARDS) - a review and proposed strategies toward a better understanding of pathogenesis, early diagnosis, and therapy.|journal=Veterinary Ophthalmology|date=July 2016|volume=19|issue=4|pages=319–31|doi=10.1111/vop.12291|pmid=26096588|hdl=2027.42/122446|url=https://deepblue.lib.umich.edu/bitstream/2027.42/122446/1/vop12291.pdf|doi-access=free}}&lt;/ref&gt; researchers at the Iowa State University (ISU) led by Dr. Siniša Grozdanić, a veterinary ophthalmologist at ISU, have successfully restored vision in two dogs who have been in 2007 successfully treated through an experimental treatment by intravenous immunoglobin (IVIg). &quot;Although the dogs won't be catching any Frisbees, they can navigate and not bump into objects,&quot;, Dr. Grozdanić notes.&lt;ref&gt;{{Cite web|title=Blind dogs can see after new ISU treatment for a sudden onset blinding disease • News Service • Iowa State University|url=https://www.news.iastate.edu/news/2007/may/blind.shtml|access-date=2021-09-15|website=www.news.iastate.edu}}&lt;/ref&gt;

Various immunosuppressive treatment regimens have been tried, but are not consistently effective.&lt;ref name=&quot;Komáromy 2016&quot; /&gt;&lt;ref&gt;{{Cite journal|last1=Young|first1=Whitney M.|last2=Oh|first2=Annie|last3=Williams|first3=Jonathan G.|last4=Foster|first4=Melanie L.|last5=Miller|first5=William W.|last6=Lunn|first6=Katharine F.|last7=Mowat|first7=Freya M.|date=November 2018|title=Clinical therapeutic efficacy of mycophenolate mofetil in the treatment of SARDS in dogs-a prospective open-label pilot study|journal=Veterinary Ophthalmology|volume=21|issue=6|pages=565–576|doi=10.1111/vop.12545|pmid=29383824|s2cid=23927483 |doi-access=free}}&lt;/ref&gt; Treatment regimens with adrenal steroids and [[thyroid]] hormones have been proposed, but as of 2016 no controlled, [[peer review]]ed studies had investigated the effectiveness of such treatments.&lt;ref name=&quot;Komáromy 2016&quot; /&gt;

==References==
{{reflist}}

[[Category:Syndromes in dogs]]
[[Category:Eye diseases]]