A 17-year-old boy, referred to as "DA," presented to the emergency room with progressive deterioration in his hearing, sight, and vitality. His symptoms included a darkening field of vision and ringing in his ears. Tests revealed that he had macrocytic anemia, a condition where his red blood cells were larger than normal, and a vitamin B12 deficiency.
Despite having normal vitamin B12 levels in his blood, further testing revealed that he had high levels of homocysteine and methylmalonic acid, indicating a functional deficiency of vitamin B12. The cause of the deficiency was attributed to his extremely limited diet, which consisted only of french fries and potato chips, both of which are devoid of vitamin B12.
The deficiency led to optic neuropathy, a condition where the nerves that carry visual information from the eye to the brain become damaged. This caused DA's vision to deteriorate, and he became legally blind. The condition also affected his hearing.
The case highlights the importance of a balanced diet and the potential consequences of malnutrition. DA's vitamin B12 injections were restarted, and he was counseled on his eating habits. While his vision loss stabilized, his optic neuropathy and associated hearing loss were not reversible.
Here are the key facts extracted from the text:
1. A 17-year-old boy, referred to as "DA", presented to the emergency room with progressive deterioration in hearing, sight, and vitality.
2. DA reported that his field of vision had been slowly going dark over the last several months.
3. DA had a history of eating only potato chips and French fries for 10 years.
4. A blood test at age 14 showed that DA had macrocytic anemia and a marked vitamin B12 deficiency.
5. DA was given vitamin B12 injections to boost his levels and was advised to add more variety to his diet.
6. Despite normal vitamin B12 levels, DA's body was not absorbing the vitamin properly.
7. A neuro-ophthalmology examination found bilateral central visual field defects, confirming blind spots in DA's field of view.
8. Nerve fiber loss was detected in both of DA's eyes.
9. DA's motor and cognitive functions were normal.
10. DA's vision was 20/200, meaning he was legally blind in the United States.
11. A slit-lamp examination found no abnormalities, and an MRI confirmed no lesions in DA's brain.
12. A test for Leber's hereditary optic neuropathy was negative.
13. Analysis of DA's blood revealed macrocytic anemia and a functional vitamin B12 deficiency.
14. DA's liver, thyroid, and vitamin B12 levels were normal, but his homocysteine and methylmalonic acid levels were elevated.
15. DA's diet was found to be the cause of his malnutrition and functional vitamin B12 deficiency.
16. DA's body weight was average for his height, but he was malnourished due to his strict diet.
17. DA's optic neuropathy was caused by his functional vitamin B12 deficiency.
18. Vitamin B12 is essential for the production of ATP and the synthesis of fatty acids in the mitochondria.
19. The absence of vitamin B12 can cause degeneration of the myelin sheath, leading to impaired nerve conduction.
20. DA's treatment included vitamin B12 injections and counseling for his eating habits.