Why it's not a good idea to keep vitamin B12 a secret: case report of thrombosis in the brain and hydrocephalus in a vegan in Sri Lanka

A new case report of an adult vegan in Sri Lanka with severe vitamin B12 deficiency was just published. The vegan suffered from hydrocephalus and a blockage due to blood clotting (thrombosis) in a major vein inside his brain. This vein is one of the veins in which the blood flows out from the brain and back into the rest of the body.  

The report was published by Priyankara et al. (National Hospital of Sri Lanka, Colombo, Sri Lanka) in the journal Case Reports in Critical Care.

Below you can see the relevant details of the case study:
  • 24-year-old vegan man
  • diagnosis: cerebral venous sinus thrombosis - which is uncommon
  • additional diagnosis: hydrocephalus - which is also very rare
  • This vegan had a severe vitamin B12 deficiency which leads to strongly increased homocysteine levels, and this can increase the risk of blood clotting (thrombosis) inside veins and arteries. 
  • In addition, this vegan had folate ("folic acid") deficiency - this is unusual, indicating that he neither consumed many vegetables nor many legumes.
  • Symptoms: The young man went to hospital because a severe headache and strange movements in his face and right arm (present for two days). He also felt drowsy. 
  • His blood pressure was increased.
  • First he first diagnosed with meningoencephalitis (inflammation of the brain).
  • He then underwent a CT scan ("CAT scan") of the brain.
  • In the hospital over the next 24 hours his condition became worse, with breathing difficulties, high blood pressure and the heart beating too slowly - this indicated that the pressure inside his brain was increasing quite quickly.
  • He was taken to the intensive care unit and received artificial respiration ("ventilation").
  • He underwent an MRI scan of the brain - which showed that there were blood clots in some of the veins in his brain as well as bleeding into the brain tissue, hydrocephalus, and damage to the white matter of the brain.
  • An external ventricular drain (EVD) was inserted - this means fluids was drain from a brain ventricle which is a hollow, fluid-filled space inside the brain.
  • He received anti-blood clotting medication.
  • Blood analysis showed that his red blood cells were too big indicating vitamin B12 and/or folate ("folic acid") deficiency.
  • Vitamin B12 in his blood and in his red blood cells was low.
  • The homocysteine concentration in his blood was very high: 50 µmol/l. 
  • Therapy: His received a vitamin B12 supplement (1000 µg/day) for two weeks (information on whether this was an oral supplement is not clearly stated). He also received folic acid (5000 µg/day) and vitamin B6 (25 mg/day) supplements. 
  • Effect of therapy: His situation improved dramatically. On day 6 artificial respiration was stopped, and on day 7 the EVD (brain fluid drainage) was stopped. On day 15 he could leave the hospital without any nerve or brain damage.
  • Follow-up: He was given the supplements. After 12 weeks his blood homocysteine concentration, as well as his blood vitamin B12 and folate ("folic acid") concentrations had become completely normal. After three months the anti-blood clotting medication (warfarin) was stopped.

 Brain scan (MRI) of the 24-year-old vegan man with severe vitamin B12 deficiency: showing hydrocephalus, oedema in the brain, and white matter abnormalities

Brain scan (magnetic resonance venography, MRV) showing blood clotting in several veins inside the brain

External ventricular drain - this image is not from the case report article

Background info:
  • Cerebral venous sinus thrombosis (CVT) accounts for about 0.5–2% of all stroke cases in adults and carries a high morbidity and mortality rate.
  • High blood homocysteine increases the risk for CVT.
  • "Our patient was a strict vegan and had folate and vitamin B12 deficiency."
  • "Our patient's homocysteine levels had come to normal levels in 12 weeks with vitamin supplementation suggesting H-Hcy [excessively high homocysteine] was purely due to folate and vitamin B12 deficiency." [not due to genetic effects]
  • "Early detection and treatment of CVT is important to prevent structural and irreversible damage in affected individuals."

Take home message:
All humans need to consume vitamin B12. Vitamin B12 is an essential nutrient. All vegans should make sure to consume reliable vegan sources of vitamin B12, i.e. vitamin B12 supplements and/or vitamin B12-fortified foods. For the recommended amounts, see here.

Priyankara, W. D. D.; Chandimal, A. V. I.; Sivagnanam, F. G.; Manoj, E. M. (2019): Cerebral Venous Sinus Thrombosis and Hydrocephalus in a Vegan Secondary to Acquired Hyperhomocystinaemia. In: Case Reports in Critical Care 2019. DOI: 10.1155/2019/1468704. (link)