Thursday, December 23, 2010

Clinical Case: A Child With Microcephaly, Cat-Like Cry.....

Clinical Vignette: A  6-month-old  child with  severe  mental  retardation is brought  to  a specialty  clinic.  Physical examination  is remarkable  for  microcephaly, a  cat-like  cry,  and an  anti-mongoloid  slant to  the palpebral fissures. This child should be further evaluated for which of the following disorders?

       A. Duodenal atresia 
       B. Hepatocellular carcinoma 
       C. Nephroblastoma  
       D. Renal cysts 
       E. Ventricular septal defect 


The  correct  answer  is  E.  This clinical vignette describes a common USMLE scenario, in which the diagnosis is not asked but something related to that diagnosis is asked. 
The  presentation  is classic  for  cri-du-chat  syndrome,  caused  by  a deletion  of the  short arm  of chromosome  5(5p-).  Approximately one-quarter  of such  patients have a  ventricular  septal  defect.  Other  features  of the  syndrome  include  short  stature,  distorted laryngeal  anatomy, profound  mental  retardation, microcephaly,  a  wide nasal  bridge,  and an  anti-mongoloid   slant   to  the  palpebral   fissures.  The   laryngeal  malformation  causes  feeding  and respiratory  difficulties, as  well as  the cat-like  cry, which  typically disappears  by age  1. Many patients survive to adulthood, but are usually institutionalized.