Patient with vomiting, diarrhea, and elevated temperature
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Kate is 18 months old and she started to throw up all of a sudden, suffered from diarrhea and had a slight fever. Her mother rushed her to the ambulant pediatrician where she was diagnosed with an acute gastroenteritis. Doctor recommended a tea diet. Therefore she was given a small amount of herbal tea every hour. When her mother came to check up on her at night, she could not wake Kate up. She shook with her but Kate did not wake up – she was unconscious most probably. Mother called an ambulance immediately.
When the ambulance arrived, the nurse performed a basic examination. Kate’s pulse was weak and much faster than usual and the girl did not respond to any stimuli. When she was examined in the ambulance car, the nurse did not find any specific signs of illness.
The nurse decided to measure the glucose level in Kate’s blood. The result was 1,1 mmol/l. Kate was therefore given a glucose infusion.
Upon the arrival to the hospital, Kate was checked by the pediatrician. She was still unconscious and reacting only to painful stimuli, her muscle tone and reflexes were increased and started shivering by the end of the examination. She was given diazepam suppository (terminating seizures and anticonvulsant effect). The doctor thought the findings were serious and it was necessary to take a quick action. The result of the second measurement of glucose level in the blood was 2,2mmol/l.
Questions:
How would you describe this glucose level ?
What sources of glucose are used by the body during fasting ?
Kate didn´t eat the last day. What nutrient should be the main energy source for her body ?
To confirm his findings, the doctor sent Kate‘s blood and urine to be examined in the lab and in the meantime she was still given the glucose infusion.
Laboratory values were:
Glycemia 2,8mmol/l
Fatty acids higher
3-hydroxybutyrate lower
Lactate 1,4mmol/l
Ammonia 102umol/l
Semi-quantitative chemical analysis of urine revealed an increased amount of acids.
More detailed urine analysis revealed: ketone bodies 0, significantly increased concentration of dicarboxylic acids.
Questions:
What is the chemical nature of ketone bodies ? When and how are they produced in the body ?
Can you find dicarboxylic acids commonly in human metabolism ?
If yes, describe their role.
If not, are there some compounds in the body that can be their precursors ?
To gain more information, did clinical biochemist GC/MS of organic acids in urine and GC/MS of acylcarnitines in plasma. The results were:
Urine organic acid by GC/MS:
normal values
Adipic acid : 164 umol/mmol creatinine <11
Suberic acid : 98 umol/mmol creatinine <3
Sebacic acid : 31 umol/mmol creatinine Not detected
3 hydroxy sebacic acid : 6 umol/mmol creatinine Not detected
Hexanoyl glycine : 25 umol/mmol creatinine Not detected
Suberyl glycine : 114 umol/mmol creatinine Not detected
GC/MS of acylcarnitines in plasma:
Massively increased concentration of hexanoyl carnitine, octanoyl carnitine and dekanoyl carnitine.
Questions:
Describe the chemical structure of adipic acid, sebacic acid and suberic acid.
Can you find these acids commonly in human metabolism ?
If yes, how are they produced ?
If not, are there some compounds in the body that can be their precursors ?
These lab results finally confirmed the diagnosis. The clinical course and lab findings provided one single explanation. GC/MS of organic acids in urine and GC/MS of acylcarnitines in plasma showed the exact localization of the defect.
The pediatrician continued in the previous treatment and Kate became conscious after 12 hours and also her neurological findings improved.
When she recovered to be sent home, the doctor had a detailed talk with her parents:
„Kate suffers from serious metabolism disorder which could endanger her life. It is important to follow these recommendations: She has to eat regularly. She must not starve longer than 6 hours otherwise she needs to get glucose infusion. If you are going to follow these, Kate is going to do well and she is not going to suffer from any serious consequences.“
Kate is 8 years old now and her development and abilities match her peers.
Questions:
Write the overview of energy metabolism and draw disorders of Kate’s metabolism before treatment (focus mainly on the metabolism of saccharides and lipids).
Try to explain reason of Kate’s state.
Kate’s hyperammonemia was not caused by defect of urea cycle enzymes, but due to faulty regulation of this metabolic pathway. Try to explain this faulty regulation.