Vitamin C (ascorbic acid) deficiency is known to affect brain function and is associated with parkinsonism.1 In 1752, James Lind, MD, described emotional and behavioral changes that herald the onset of scurvy and precede hemorrhagic findings.2 The World Health Organization (WHO) today refers to this stage as latent scurvy.3 The 2 case studies that follow present examples of patients with vitamin C deficiencies whose parkinsonism responded robustly to vitamin C replacement. These cases suggest that vitamin C deficiency may be a treatable cause of parkinsonism.
Case 1
Mr. A, a 60-year-old white male, was admitted to the Medicine Service for alcohol detoxification. The patient had a history of alcohol dependence, alcohol withdrawal seizures, tobacco dependence, and hyperlipidemia. He took no medications as an outpatient. On admission Mr. A’s body mass index (BMI) was 27.2. An initial examination revealed a marked resting tremor of the patient’s right hand with cogwheeling, which had not been present in examinations conducted in the previous 3 years. Mr. A had no prior history of a tremor. He had no cerebellar findings and no evidence of asterixis or of tremulousness associated with high-output cardiac states, such as de Musset sign.
Mr. A reported he had experienced the tremor for a month and that it had been worsening. He also was having difficulty using his dominant right hand, for routine daily activities. Mr. A was oriented, and his short-term memory was intact. He was ill-appearing, irritable with psychomotor slowing, and did not wish to rise from his bed. He had no gingival or periungual bleeding and did not bruise easily. He had no corkscrew hairs. The patient was started on no medications known to cause extrapyramidal symptoms (EPS).
In the hospital, the tremor persisted unabated for 2 days. On the third day, Mr. A was started on 1,000 mg vitamin C IV twice daily. He received a total of 2,000 mg IV that day, but the IV fell out, and he refused its replacement. Several hours later, Mr. A stated that he felt much better, got out of bed, and asked to go outside to smoke. The author noted complete resolution of the right hand tremor and cogwheeling 20 hours after starting the vitamin C IV. Mr. A refused a repeat serum vitamin C assay.
Laboratory studies initially revealed that Mr. A had hyponatremia with a serum sodium of 121 mmol/L (normal range: 133 to 145 mmol/L) as well as hypokalemia with a serum potassium of 3.2 mmol/L (normal range: 3.5 to 5.0 mmol/L). He was hypoosmolar, with a serum osmolality of 276 mOsm/kg (normal range: 278 to 305 mOsm/kg). His vitamin C level was low at 0.2 mg/dL (normal range: 0.4 to 2.0 mg/dL). Mr. A also had a serum vitamin C level drawn 2 years prior that showed no symptoms of EPS, and at that time, the reading was 0.7 mg/dL. At admission to Medicine Services, Mr. A had a serum alcohol level of 211 mg/dL. Neuroimaging revealed diffuse cerebral and cerebellar volume loss.
Normal laboratory results included serum levels of vitamin B12, red cell folate, homocysteine, methylmalonic acid, free and total carnitine, alkaline phosphatase, manganese, and zinc. A urine drug screen was negative.
Case 2
Mr. B, a 69-year-old black male, was admitted to the hospital for depression complicated by alcohol dependence. He also had tobacco dependence, type 2 diabetes mellitus, hypertension, and gout. The patient’s BMI at admission was 16.1. Mr. B appeared ill, was worried about his health, and remained recumbent unless asked to move. He reported that his right hand had begun to shake at rest in the month prior to admission. The tremor made it difficult for him to drink. He pointed out stains on his hospital gurney from an attempt to drink orange juice prior to being assessed.
A physical examination revealed a distinct resting tremor with cogwheeling of the right hand; there was no other evidence of EPS, nor was there evidence of cognitive, cerebellar, or skin abnormalities, such as hemorrhages or corkscrew hairs. Asterixis was absent as was evidence of a high-output cardiac state that might produce a tremor, such as de Musset sign. A serum vitamin C level was obtained and returned at 0.0 mg/dL. A head computed tomography scan obtained the next day revealed mild cerebellar volume loss. A serum alkaline phosphatase level was elevated slightly at 136 U/L (normal range: 42 to 113 U/L). Normal serum values were returned for zinc, vitamins B12 and folate, rapid plasma reagin, sodium, and serum osmolality. A urine drug screen was negative, and serum alcohol level was < 5.0 mg/dL.
Mr. B took no medications expected to cause EPS. He received no micronutrient replacement until the day after admission when he began receiving oral vitamin C 1,000 mg twice a day. After receiving 3 doses, Mr. B’s resting tremor and cogwheeling completely resolved. He noticed he had stopped shaking and could now drink without spilling fluids. He also got out of bed and began interacting with others. Mr. B said he felt he was “doing well.” A repeat serum vitamin C level was 0.2 mg/dL on that day. The improvement was sustained over 3 days, and Mr. B was discharged to home.
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