Thiamine neuropathy

Genetic testing

NCV/EMG

Laboratory

Imaging

Biopsy

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Anatomy/distribution

Symptoms

Clinical syndrome/ signs

Pathogenesis

Diagnosis

Differential diagnosis

Therapy

Prognosis Reference

Thiamine deficiency causes degeneration of sensory and motor nerves, vagus, recurrent laryngeal nerve, and brainstem nuclei. Lactate accumulates in axons due to the absence of thiamine diphosphate and transketolase.

The symptoms indicate a sensory and motor neuropathy: distal paresthesias, aches and pains, and limb weakness.

"Dry Beriberi" is characterized by painful distal paresthesias, ankle areflexia, and motor weakness. "Wet Beriberi" combines the neuropathy with cardiac failure. "Wernicke-Korsakoff Syndrome", resulting from long-term thiamine deficiency, causes CNS dysfunction that includes confusion, memory loss, oculomotor and gait problems.

Beriberi is caused by states of poor nutrition: starvation, alcoholism, excessive and prolonged vomiting, post-gastric stapling, or unbalanced diets of carbohydrates without vitamins, protein, or fat (polished, milled rice or ramen noodles). The importance of thiamine to carbohydrate metabolism may be the cause of the nervous system damage.

CMAPs and SNAPs are reduced or absent, with distal denervation. RBC transketolase, serum lactate, and pyruvate may elevate after glucose loading.

The sensory motor neuropathy caused by beriberi is similar to other causes of non-specific sensory motor neuropathy. Facial and tongue weakness, and recurrent laryngeal nerve deficiency are uncommon in other causes of sensory motor neuropathy, and should suggest beriberi.

For Wernicke-Korsakoff patients: 100 mg thiamine IV and 100 mg IM immediately, plus 100 mg IM or orally for three days. Without Wernicke-Korsakoff, restore a nutritious diet with additional thiamine.

Improvement varies with thiamine replacement. The non-neuronal components respond well, but neuropathic beriberi may result in permanent impairment.

Kril JJ (1996) Neuropathology of thiamine deficiency disorders. Metab Brain Dis 11: 9-17

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