Intestinal giardiasis presenting as acute sensory ataxia

Abstract

© Author(s) (or their employer(s)) 2021. No commercial reuse. See rights and permissions. Published by BMJ. A 20yearold student presented with progressive swaying while walking, worse in the dark, for 2 weeks. He was a lifelong vegetarian but had no other comorbidities. There was no family history of any neurological illness. On examination, he had grossly impaired vibration and joint position sense in both lower limbs with preserved light touch, pain and temperature sensations. There were no motor or cerebellar deficits and reflexes were normal. Palpation of nerves did not reveal any thickening or nodularity. Blood investigations showed macrocytosis with a mean corpuscular volume of 117 fL, haemoglobin of 146 g/L and moderate eosinophilia (14%). Vitamin B12 levels were low (55 pg/mL) with normal folate levels. Nerve conduction studies were normal. MRI of the brain with whole spine showed T2/fluidattenuated inversion recovery (FLAIR) hyperintensities in bilateral deep white matter along with T2/FLAIR hyperintensities in the posterolateral region of the thoracic cord which was suggestive of vitamin B12 deficiency (figure 1). Erythrocyte sedimentation rate was 14 mm/first hour. Fasting and postprandial sugar levels as well as glycated haemoglobin level were normal. Fasting lipid profile revealed hypertriglyceridemia (303 mg/dL), but was otherwise normal. Screening for inborn errors of metabolism by tandem mass spectroscopy was negative. Chest Xray was normal. Serology for HIV, hepatitis B and hepatitis C, antinuclear antibody, and serology for syphilis and serum copper were within normal limits. He was treated with intravenous cyanocobalamine 1000 μg daily for 1 week, followed by weekly for a month. Oesophagogastroduodenoscopy was done to evaluate for cause of vitamin B12 deficiency. The gastric and duodenal mucosae were grossly normal but duodenal biopsy showed lymphoplasmacytic infiltrate in the lamina propria with several flagellate, pearshaped binucleate Giardia parasites on the luminal surface of the mucosa (figure 2). Serum parietal cell antibody and serum intrinsic factor antibody were negative. Within 1 week of starting parenteral B12 supplementation, he improved significantly and was able to walk with minimal support. He was given albendazole 400 mg orally daily for 3 days. At followup after 1 month, he was asymptomatic, except for minimal swaying while walking in dim light. At 1year followup, he was completely asymptomatic.