A 16-year-old high school student with a 4-year history of diabetes mellitus was
ID: 149322 • Letter: A
Question
A 16-year-old high school student with a 4-year history of diabetes mellitus was brought to the emergency department because of excessive drowsiness, vomiting, and diarrhea. His diabetes had been well controlled with 40 units of NPH insulin daily until several days ago, when he developed excessive thirst and polyuria. For the past 3 days he has also had headaches, myalgia, and a low-grade fever. Diarrhea and vomiting began 1 day ago. Chemistry and Urinalysis results are listed below:
Based on the clinical symptoms and laboratory results, what is the most likely diagnosis? (Be specific!)
Why are the ketones positive?
What test could be used to measure the serum and urine ketones? What is the principle of the test? Which ketone bodies are measured?
What are two options that could be used long-term to monitor this patient’s glucose levels? What is the principle behind each method?
Urinalysis Results Chemistry Results Specific Gravity 1.012 5.0 Sodium Potassium Chloride Bicarbonate BUN Creatinine Serum ketones 126 mEa/L 6.1 mEa/L 87 mEa/L Glucose Ketone Large 48 mg/dL 2.0 mg/dlExplanation / Answer
1: Excessive thirst, polyuria, increased urine specific gravity, ketones in serum and urine and electrolyte imbalance are the symptoms of type 1 diabetes in which absolute deficiency of insulin secretion causes hyperglycemia.
2: The deficiency of insulin secretion makes the cells unable to pick glucose from blood. Glucose is not avaiable as energy source and cells use lipids as alternative. beta oxidation of fats produce acetyl CoA which in turn is converted into ketone bodies in liver. Ketone bodies are the water soluble fuel that is delivered to brain cells and other tissues when glucose is not available.
3: Rothera'a test measures presence of acetone and acetoacetate in urine. It is based on the principle that Nitroprusside in alkaline medium reacts with ketone group to form purple ring. Presence of beta hydroxy butyrate is measured indirectly by first removing acetone and acetoacetate from urine. This is done by adding acetic acid to urine followed by Rothera's test. Gerhard's test is done for diacetic acid based on the priciple that acetoacetate is converted into acetone upon boiling and does not tests positive for acetocetate which other wise gives purple color.
4: Urine analysis and blood test can be done to observe the kidney function and nutrient levels in blood. Glycated hemoglobin test tells about average blood sugar level for last 3 months. Type 1 diabetes leads to higher blood sugar level due to no insulin secretion and causes kidney damage due to formation of ketone bodies and electrolyte imbalance
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