WBR0502

Author	[[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Behavioral Science/Psychiatry
Sub Category	SubCategory::Endocrine
Prompt	[[Prompt::A 7-year-old boy is brought to the pediatrics clinic for fever of 39 °C (102.2 °F), cough, and wheezing for the past week. Over the last 24 hours, the child has developed nausea, vomiting, and watery diarrhea. The child's past medical history is significant for neurofibromatosis, asthma, and seizure disorder. He is currently taking daily albuterol and valproic acid. His mother explains that she was diagnosed with insulin-dependent diabetes mellitus at his age and fears he may have developed it too. On physical examination, you note a lethargic and ill-appearing boy. His heart rate is 96/min, blood pressure is 124/84 mm Hg, temperature is 36.8°C (98.2°F), and respiratory rate is 28/min. You decide to admit the child for evaluation and monitoring. Over the next two days, the patient has recurrent episodes of hypoglycemia, with fingerstick glucose levels as low as 33 mg/dL. Both episodes occur at night, with the mother alerting the nurses each time. Further investigation reveals a serum insulin level of 2344 µU/mL (5–25 µU/mL) and a C-peptide level of 0.7 ng/mL (0.8–4.0 ng/mL). What is the most likely diagnosis in this patient?]]
Answer A	AnswerA::Insulinoma
Answer A Explanation	AnswerAExp::
Answer B	AnswerB::Sulfonylurea intake
Answer B Explanation	AnswerBExp::
Answer C	AnswerC::Exogenous insulin administration
Answer C Explanation	AnswerCExp::
Answer D	AnswerD::Type 1 diabetes mellitus
Answer D Explanation	AnswerDExp::
Answer E	AnswerE::Adrenal insufficiency
Answer E Explanation	AnswerEExp::
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient in this scenario is presenting for recurrent hypoglycemic episodes that are most likely related to exogenous administration of insulin. The classical triad in of patients with true hypoglycemia is known as the Whipple's triad. It consists of (1) symptoms known or likely to be caused by hypoglycemia, (2) a low plasma glucose measured at the time of the symptoms, and (3) a relief of symptoms when glucose level is restored to normal. In patients who are not diabetic, a thorough work-up to uncover the etiology of hypoglycemia is indicated. Insulin levels followed by measurement of C-peptide and proinsulin in patients with elevated insulin levels are required as a primary assessment. In patients with elevated C-peptide, further evaluation for sulfonylurea abuse, insulinoma, or autoimmune hypoglycemia. Autoimmune syndromes are a rare cause of hypoglycemia and can be diagnosed by screening for specific antibodies. In patients with low C-peptide i.e. low endogenous production of insulin, and high insulin levels, the cause is exogenous insulin administration and is almost always factitious. This patient is a victim of Munchausen's syndrome by proxy, whereby the mother Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Insulin, WBRKeyword::Insulinoma, WBRKeyword::Munchausen's syndrome by proxy, WBRKeyword::Hypoglycemia, WBRKeyword::C-peptide
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::