Saturday, April 29, 2017

Phocomelia

Phocomelia is defined as 'seal limb'- a birth anomaly (i.e., congenital malformation) in which the hands are essentially attached to the chest.  There may be a short bone connecting the hands to the chest, either a forearm bone or arm bone, but not both.  Phocomelia is incredibly rare and really became a recognized abnormality in relation the the thalidomide epidemic in the late 1950s and early 1960s.  Thalidomide was approved for use (actually without even a prescription in Germany) as it had proven safe in animal experiments.  It was used for morning sickness and nausea in pregnant women, especially in the first trimester (which happens to be when the limbs develop and form). There was an explosion of cases of phocomelia in both Europe and Australia  and Canada (rare in the USA as the drug was never approved for use).  Thankfully, the source of the increased incidence of phocomelia was identified and the drug was removed from use (it has recently been used for nausea in chemotherapy for those without a chance of being pregnant).  There have been notable books and articles on this terrible epidemic.  50 years after the epidemic, the drug manufacturer, Grunenthal, finally apologized.

Dark Remedy: outstanding book exploring the thalidomide- phocomelia epidemic.
Specifically defined, phocomelia means a segmental deficiency of the extremity, typically an absence of the either the arm or forearm segment.  But, it is important to remember that the segments that are present, including the hand, are never normal.  In 2005, we shared the St. Louis and Dallas experience around patients diagnosed with phocomelia.  We examined the extensive patient experience at three busy hospitals: Texas Scottish Rite, St. Louis Shriners Hospital, and St. Louis Childrens Hospital to assess all patients with a diagnosis of phocomelia.  We learned that most of the kids so diagnosed really had either a severe form of radial longitudinal deficiency More information on RLD or ulnar longitudinal deficiency More information on ULD and NOT phocomelia.  We established and defined the Type 5 radial and ulnar deficiency in the manuscript describing our findings:  Manuscript Link  There were some kids in our large group that could not be labeled as radial or ulnar longitudinal deficiency- those were kids more likely to have the segmental deficiency of phocomelia.

So while most kids that appear to have phocomelia really have either a radial or ulnar longitudinal deficiency, some will truly have a segmental defect as phocomelia.  Typically this is likely a spontaneous mutation or birth defect but there are some inherited patterns such as Roberts Syndrome, among others listed at OMIM- OMIM syndrome list.

I am grateful that the family of this child agreed to allow us to post pictures and x-rays to demonstrate the appearance of phocomelia.

Patient with phocomelia.  Note the limited hand development.

Patient with phocomelia.  Note the limited hand development.

X-ray of phocomelia patient.  There are several fingers and a short bone attaching to the chest.

Patients with phocomelia have functional challenges primarily because the limbs are short.  Getting the hands to the mouth and using the toilet are tough due to the length of the arms.  This patient has normal lower extremities and some kids will chose to use their feet for functional activities including writing and eating.  We absolutely support this type of functional activity and sometimes have to encourage schools to be supportive of this as well.  In addition, there are therapy tools and tricks which can help with all sorts of daily activities to make life easier.  Finally, surgery is only very rarely indicated and is typically focused on either stabilizing digits or lengthening the bones that are present.

Charles A. Goldfarb, MD
My Publication List
congenitalhand@wudosis.wustl.edu

No comments:

Post a Comment