This week’s case record of the Massachusetts General Hospital in the New England Journal of Medicine (1) is one of a 19-month-old child with failure to thrive. These case records, formerly called clinical pathologic conferences, appear in each issue of the NEJM and describe cases of rare and difficult to diagnose problems. They show week after week that the history is by far the most important tool for diagnosis. Laboratory studies and x-rays rarely help although they are always done in great profusion. Even physical exam, apart from just looking and interacting with the whole patient, is usually of little help in diagnosis. “Listen to your patient, he is telling you the diagnosis,” Doctor William Osler said.
The standard tactic for trying to make a difficult diagnosis is called the differential method. What are all the diseases that can cause this constellation of findings and what is the best method to diagnose each member of that differential? But a simpler distillation is called by me “the Aunt Millie method.” How do you know that that is your Aunt Millie? She has brown hair and two eyes and … whatever, but really you just instantly put it all together and you know that that is your Aunt Millie with almost 100% accuracy. But it is important to remind everybody that in the day to day practice of medicine in doctor’s offices, many symptoms go undiagnosed. “I don’t know,” is a common diagnosis. Certainty is not part of this business. And even well described diseases are slightly, or not so slightly different, in every individual human that gets those diseases.
Final proof of diagnosis in these case reports is usually the pathological report, either from an autopsy after the patient dies or a strategic biopsy or tissue sample.
This 19 month old Puerto Rican girl stopped gaining weight after about 7 months of age. She was otherwise happy and active and healthy. She ate lots of good food and even high calorie supplements prescribed by a nutritionist. Her development was normal. Her height and head growth were also normal. Scads of laboratory tests were normal.
Failure to thrive is the final common pathway for an endless list of diseases in children. Usually it is caused either by obvious severe disease like infection or heart or lung or nervous system problems, or it is caused by terrible social and environmental deprivation. Even though failure to thrive is commonly classified according to calorie arithmetic, this is almost always not helpful. Spending time trying to explain it by counting calories never solves the diagnosis.
So this little girl didn’t fit the usual picture. But she looked like the picture of diencephalic syndrome which is caused by a brain tumor in the area of the hypothalamus near the crossing of the nerves from the eyes – the optic chiasm. So they did an MRI of the brain and saw a tumor and took a biopsy of it to prove the diagnosis. She was treated with chemotherapy and after 3 months her tumor shrank by 25% and her weight increased by 37%.
Nobody knows what causes the diencephalic syndrome, also called Russell’s syndrome, first described by Dr. Russell in 1951. It is very rare. Different kinds of brain tumor and only 20% of brain tumors in this region of the brain cause the diencephalic syndrome.
If you want to find a magic bullet to cure obesity, figure out the cause of diencephalic syndrome.
John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- firstname.lastname@example.org or phone-354-6605.