Thiamine deficiency

Last revised by Calum Worsley on 9 Oct 2023

Thiamine deficiency is caused by a low level of thiamine (vitamin B1) in the body, and when severe, a deficiency may manifest in adults as beriberi.
There are two main forms:

  • wet beriberi: high-output cardiac failure predominates

  • dry beriberi: neurological dysfunction predominates

In practice patients may present with mixed beriberi, i.e. with elements of both the wet and dry forms.

  • high output heart failure:

    • symptoms may include dyspnea, palpitations, fatigue

    • exam may reveal signs of elevated filling pressures including jugular venous distention and/or pulmonary vascular congestion

    • periphery may be warm with vigorous palpable arterial pulses

    • bedside point of care ultrasonography may demonstrate:

      • dilation of the inferior vena cava with diminished respiratory variation

      • bilateral, symmetric lung rockets (>3 B lines per sonographic field) in a gravitationally dependent distribution

      • an elevated left ventricular outflow tract velocity time integral (VTI) consistent with a high stroke distance (and by extension cardiac output)

  • altered mentation

    • ranging from subtle memory impairment to profound encephalopathy

  • ataxia

    • vestibulo-cerebellar dysfunction predominantly affecting the lower extremities and gait

  • visual disturbance

    • particularly oculomotor abnormalities e.g. nystagmus, ophthalmoplegia

  • sensory and/or motor deficits

    • axonal degeneration with resultant myopathy and neuropathy

    • areflexia may also be noted

Tachycardia is common with early in the disease course, and assessment of a core temperature may demonstrate hypothermia. Tachypnea may also be present with a respiratory alkalosis on a blood gas. An elevated serum lactate may be present.

Confirmatory testing may include a whole blood thiamine level or an erythrocyte transketolase activity; the latter may be reassessed after thiamine repletion. can confirm the diagnosis.

Deficiency is typically related to insufficient thiamine intake, decreased gastrointestinal absorption, or increased elimination. Congenital causes are also a consideration, albeit with a far lower incidence.

The imaging features of beriberi reflect its underlying manifestations, and therefore in dry beriberi, cardiomegaly, pulmonary edema, dilated cardiomyopathy may be seen; however there are no pathognomonic cardiac imaging findings 5.

In dry beriberi the classic MRI features of Wernicke encephalopathy may be seen.

In general radiology is a corroborative tool in beriberi. The diagnosis is usually clinical with response to supplemental thiamine confirmatory.

Optimal treatment of beriberi relies upon a two-pronged approach:

  • thiamine supplementation

    • commonly administered parenterally, often with magnesium

    • biotin may be administered for certain genetic causes e.g. loss of low-affinity thiamine uptake transporter function

  • supportive therapies e.g. cardiac support

Recovery is often rapid once thiamine supplements are started. 

Beriberi derives from the Sinhalese for "weak, weak", a deliberate duplication of the same word to emphasize how poorly a patient with the condition feels 2.

An unrecognized nutrient on the surface of rice which was eliminated during the polishing process was speculated to be the nutritional factor deficient in beriberi in 1901 by Gerrit Grijns (1865-1944). The structure of thiamine was defined by Robert R Williams (1886-1965) and colleagues in 1934, and in 1936 was demonstrated in an avian model to reverse the metabolic derangement in aerobic glucose utilization present in thiamine deficiency.

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