Gastrointestinal Symptoms and Lactic Acidosis in a Chronic Marijuana User

Discussion

Gastrointestinal beriberi has been reported in chronic cannabis users who present with nausea, vomiting, epigastric pain, leukocytosis, and lactic acidosis; all these symptoms rapidly improve after thiamine administration.^5,6 The patient’s dietary change also eliminated her intake of vitamin B₁₂, which compounded her condition. Thiamine deficiency produces lactic acidosis by disrupting pyruvate metabolism.⁷ Bradycardia also can be a sign of thiamine deficiency, although the patient’s use of clonidine for migraines is a confounder.⁸

Chronically ill patients are prone to nutritional deficiencies, including deficiencies of thiamine.^7,9 Many patients with chronic illnesses also use cannabis to ameliorate physical and neuropsychiatric symptoms.² Recent reports suggest cannabis users are prone to gastrointestinal beriberi and Wernicke encephalopathy.^5,10 Treating gastrointestinal symptoms in these patients can be challenging to diagnose because gastrointestinal beriberi and CHS share many clinical manifestations.

The patient’s presentation is likely multifactorial resulting from the combination of gastrointestinal beriberi and CHS. However, thiamine deficiency seems to play the dominant role.

There is no standard treatment regimen for thiamine deficiency with neurologic deficits, and patients only retain about 10 to 15% of intramuscular (IM) injections of cyanocobalamin.^11,12 The British Committee for Standards in Haematology recommends IM injections of 1,000 mcg of cyanocobalamin 3 times a week for 2 weeks and then reassess the need for continued treatment.¹³ The British Columbia guidelines also recommend IM injections of 1,000 mcg daily for 1 to 5 days before transitioning to oral repletion.¹⁴ European Neurology guidelines for the treatment of Wernicke encephalopathy recommend IV cyanocobalamin 200 mg 3 times daily.¹⁵ Low-level evidence with observational studies informs these decisions and is why there is variation.

The patient’s serum lactate and leukocytosis normalized 1 day after the administration of thiamine. Thiamine deficiency classically causes Wernicke encephalopathy and wet beriberi.¹⁶ The patient did not present with Wernicke encephalopathy’s triad: ophthalmoplegia, ataxia, or confusion. She also was euvolemic without signs or symptoms of wet beriberi.

Conclusions

Thiamine deficiency is principally a clinical diagnosis. Thiamine laboratory testing may not be readily available in all medical centers, and confirming a diagnosis of thiamine deficiency should not delay treatment when thiamine deficiency is suspected. This patient’s thiamine levels resulted a week after collection. The administration of thiamine before sampling also can alter the result as it did in this case. Additionally, laboratories may offer whole blood and serum testing. Whole blood testing is more accurate because most bioactive thiamine is found in red blood cells.¹⁷