Bury the Buzzword: Cherry-red Coloration

This post addresses the large differential diagnosis of the buzzword Cherry-red coloration. The cherry-red coloration most often refers to the macula located on the retina of the eye, but it can also refer to the coloration of the skin, esophagus, and epiglottis.

The cherry-red spot on the macula is seen on funduscopic examination. It is observed in the middle of the macula and has a pale-yellow or white area around it. This buzzword could be considered a misnomer, because the cherry-red spot is theoretically a normal finding. It becomes visually enhanced by the pathological discoloration of the retina surrounding it.

The macula is the area located a few millimeters lateral to the optic disc. There is a circular area in the middle of the macula termed the fovea, and a circular area in the middle of the fovea termed the foveola. These anatomical terms are important to understand the pathophysiology.

The cherry-red spot on the macula is most commonly caused by the metabolic diseases listed below. These metabolic diseases are characterized by buildup of storage material in the retina, which causes it to have a pale-yellow or white discoloration. However, the foveola does not collect these deposits so the blood vessels are still able to be seen through it, allowing it to remain a cherry-red color.

Select metabolic diseases causing a cherry-red spot on the macula:

·        Tay-Sachs disease

·        Sandhoff disease

·        Sialidosis

·        Niemann-Pick disease

·        GM1 Gangliosidosis

·        Galactosialidosis

·        Metachromatic leukodystrophy

·        Farber’s disease

·        Goldberg’s disease

·        Gaucher’s disease

·        Hurler’s syndrome

There are also other metabolic diseases that have been associated with a cherry-red spot on the macula, but the ones listed above are the most board relevant.

After the metabolic diseases, the next most board relevant condition causing a cherry-red spot on the macula is central retinal artery occlusion. Since the retinal artery is blocked, the loss of blood supply causes a white discoloration of the retina. The fovea remains a cherry-red color because it receives its blood supply from the choroid (the vascular layer of the eye), and not the retinal artery.

Additional conditions causing a cherry-red spot on the macula include orbital ischemia and orbital contusion due to constriction of the arteries. Quinine, dapsone, methanol, and carbon monoxide poisoning are substance-induced causes.

Cherry-red discoloration of the skin can also be found in carbon monoxide poisoning, as well as cyanide poisoning. Furthermore, cherry-red discoloration of the esophagus can be due to esophageal varices and cherry-red discoloration of the epiglottis can be due to epiglottitis.

In conclusion, cherry-red coloration can be due to a variety of different pathology. It is important to not jump too quickly to a diagnosis because the answer may not always involve the macula. It is imperative to take the entire clinical scenario into context when dealing with this buzzword.

Sources:

Fauci, Anthony S., and Tinsley Randolph Harrison. Harrison's Principles of Internal Medicine. 17th ed. New York: McGraw-Hill Medical, 2008. Print.

Goljan, Edward F. Rapid Review Pathology. 3rd ed. Philadelphia, PA: Mosby/Elsevier, 2010. 4, 86, 601. Print.

Le, Tao, and Vikas Bhushan. First Aid for the USMLE Step 1. 2010 ed. New York: McGraw-Hill Medical, 2010. 111, 183, 417, 516. Print.

Suvarna JC, Hajela SA. Cherry-red spot. J Postgrad Med [serial online] 2008 [cited 2011 Dec 5];54:54-7. Available from: http://www.jpgmonline.com/text.asp?2008/54/1/54/39196