A two-and-a-half-year-old boy presented to the pediatric emergency department with the symptoms of becoming groggy and unconscious. 5 days ago, he was vaccinated with pneumococcal conjugate vaccines (PCV). He felt faint for lack of food over 15 hours and was dysuria about 5 hours. He was starting to manifest as hyperventilation in relation to onset. His parents denied any accompanied signs, such as fever, cough, stomachache, headache seizures and apneic spells.
At the time of presentation, his physical examination revealed a temperature of 36.5℃, a heart rate of 98 beats per minute and a respiratory rate of 26 breathes per minutes. His oxyhemoglobin saturation was 98% in the supine posture. He had a very negative response to the painful stimuli. Pupil reaction to light was preserved in the lethargic boy and his lips were slightly dry. The cardiovascular physical examination focused on features of murmur, auscultation over the heart valves and assessment of peripheral perfusion. All findings on cardiac examination were normal. Absence of abnormalities on chest auscultation reduced the possibility of catching respiratory diseases. What’s more, he exhibited negative symptoms of abdomen distends and bellyache. Normal bowel sounds were present at the same time. Meanwhile, the abdominal examination reveal the normal size of liver and spleen. The neurologic examination, including Kernig sign, Brudzinski sign, Babinski sign, Gordon sign, Oppenheim sign and primitive reflexes, were normal as well.
He had been in recurrent low spirits for nearly one year and recovered after food feeding. However, it is the first record for him to manifest as coma. He was born with a normal history of pregnancy and delivery. There were no history of consanguineous marriage or chronic disease in his family. His six-year-old brother was also physical healthy. He received all childhood vacations, including hepatitis B vaccine, the Bacilli Calmette-Guerin (BCG) vaccine, polio vaccine, Diphtheria-Tetanus-Pertussis, measles vaccine, encephalitis vaccine and PCV. His parents denied history of hospitalization, traumatism and allergic reactions to drugs. Besides, he had normal growth and intellectual development.
Diagnostic Studies
Library tests included C-reactive protein (CRP), procalcitonin (PCT), glucose, blood ammonia, lactic acid and fasting insulin. Serum level of alanine aminotransferases (ALT) and aspartate aminotransferases (AST) were detect at the same time. All results were present in Table 1. Electrocardiograph (ECG) and echocardiography (UCG) were applied to evaluate cardiac structure and function. Other imaging examinations were also shown normal, such as ultrasound (abdomen) and brain magnetic resonance imaging (MRI) (Fig.1).
Genetic Analysis
After we received informed consent from his parents, blood samples of proband and his parents were collected to identify mutations in FBP1 gene. His little brother didn’t participate in the test. High-throughput sequencing (NGS) was adopted in this study. The results showed that G164S (c.490G>A) in exon 4 and P308R (c.923C>G) in exon 7, respectively detected from his father and mother, had a high risk of pathogenic potentiality. As both alleles of a diploid parent were different, his parents were all heterozygous at different loci. The child inherited G164S and P308R from each parent and then constituted a compound heterozygous mutation. Both mutations were caused by single-base substitution. All results of genetic analysis are shown in Table 2 and Fig 2.
Treatments
He put on a drip with glucose at a pace of 5 ml/kg/h. The patient received antibiotic therapies and liver-protecting drugs. 7 days later, abnormal levels in the blood returned to previous values. The level of glucose fluctuated from 4.5 mmol/L to 6.0 mmol/L when he discharged from hospital.
Follow-up
We suggested the little boy to reduce intake of fructose and sucrose and avoid prolonged fasting and febrile diseases, which could increase the risk of metabolic decompensation. He rarely manifests as hypoglycemia. He is in kindergarten now. he could perform an astonishing variety of accomplishments, such as drawing, singing and even reciting.