Congenital hypothyroidism differential diagnosis

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Differentiating Diagnosis

• Rickets
• Down's syndrome
• Congenital megacolon

Congenital hypothyroidism must be differentiated from other diseases that cause a failure to pass meconium or abdominal distension in infants, including meconium plug syndrome, small left colon syndrome, and Hirschsprung's disease.

Disease	Prominent clinical features	Radiological findings
Meconium plug syndrome	Transient intestinal obstruction for 1-2 days after birth. Obstruction is functional due to dilated colon and delayed passage of feces. Usually seen in premature infants.	Abdominal x-ray with contrast showing inspissated meconium in the intestine, proximal to the colon - Case courtesy of Radswiki, Radiopaedia.org, rID 11606
Small left colon syndrome	Reduced caliber of the colon starting from splenic flexure and going down, causing intestinal obstruction. Characterized by a sudden change of the colon diameter. Usually associated with gestational diabetes.	Abdominal x-ray with contrast, shows decreased caliber of the descending and sigmoid colon, loss of haustration along with filling defects corresponding to retained feces - Case courtesy of Dr Eric F Greif, Radiopaedia.org, rID 30024
Distal small intestine/colon atresia	Failure to pass meconium due to failure of intestine recanalization. Proximal lesions have an earlier onset of symptoms than distal lesions. Colonic atresia may affect normal children or may be associated with other abnormalities as Hirschsprung's disease or gastroschisis.	Normal appearing colon that is small and unused. Contrast fills the whole colon and passes to the ileum - Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID 5959
Meconium ileus	Intestinal obstruction due to inspissation of meconium in the distal ileum. Most cases of meconium ileus are secondary to cystic fibrosis. Typically presents with failure to pass meconium and abdominal distension with or without vomiting. Meconium ileus may first present with complications, including perforation and volvulus.	Contrast enema shows inspissated meconium starting from the mid-sigmoid colon and going up till the splenic flexure. The colon is normal in diameter, ruling out microcolon - Case courtesy of Dr Michael Sargent, Radiopaedia.org, rID 6009
Congenital hypothyroidism	Most infants are born asymptomatic. Symptoms, if present, may include, but not limited to: Macroglossia Hoarse cry Umbilical hernia Puffy facies Increased head circumference Hypothermia