History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include chronic alcohol excess, a staple diet of polished rice, age <1 year in endemic thiamine deficient region, malnutrition, gastrointestinal surgery, recurrent vomiting (e.g., hyperemesis gravidarum), chronic diarrhoea, and refeeding and total parenteral nutrition.
ocular abnormalities (Wernicke's encephalopathy)
Acute, severe deficiency may lead to Wernicke's encephalopathy, which is characterised by the classic triad of mental state changes (e.g., acute confusion), ataxia, and ocular abnormalities (e.g., nystagmus and strabismus).
Other diagnostic factors
common
confusion (Wernicke's encephalopathy)
Acute, severe deficiency may lead to Wernicke's encephalopathy, which is characterised by the classic triad of mental state changes (e.g., acute confusion), ataxia, and ocular abnormalities (e.g., nystagmus and strabismus).
It should be noted that this is a common, non-specific sign in patients presenting to hospital.
ataxia (Wernicke's encephalopathy)
Acute, severe deficiency may lead to Wernicke's encephalopathy, which is characterised by the classic triad of mental state changes (e.g., acute confusion), ataxia, and ocular abnormalities (e.g., nystagmus and strabismus).
fatigue
The early, subclinical stages of vitamin B1 deficiency present with non-specific symptoms, such as fatigue and muscle aches.
muscle aches
The early, subclinical stages of vitamin B1 deficiency present with non-specific symptoms, such as fatigue and muscle aches.
incessant crying (infantile beri-beri)
Initially a loud, hoarse cry, which evolves into a “silent cry,” or aphonia.
anorexia (infantile beri-beri)
Refusal to breastfeed or loss of appetite.
bulging fontanelle (infantile beri-beri)
In areas with low awareness of thiamine deficiency, symptoms are easily mistaken for meningitis.[1]
dyspnoea (wet beriberi)
Symptom of cardiac failure in wet beriberi due to acute or chronic deficiency.
orthopnoea (wet beriberi)
Shortness of breath on lying flat is a symptom of cardiac failure in wet beriberi due to acute or chronic deficiency.
tachycardia (wet beriberi)
Sign of cardiac failure in wet beriberi due to acute or chronic deficiency.
peripheral cyanosis (wet beriberi)
Sign of cardiac failure in wet beriberi due to acute or chronic deficiency.
peripheral oedema (wet beriberi)
Sign of cardiac failure in wet beriberi due to acute or chronic deficiency.
decreased sensation (dry beriberi)
Dry beriberi is characterised by a distal peripheral polyneuropathy (particularly of the legs) with paraesthesia, reduced knee jerks and other tendon reflexes, and progressive severe weakness with muscle wasting.
reduced tendon reflexes (dry beriberi)
Dry beriberi is characterised by a distal peripheral polyneuropathy (particularly of the legs) with paraesthesia, reduced knee jerks and other tendon reflexes, and progressive severe weakness with muscle wasting.
muscle weakness (dry beriberi)
Dry beriberi is characterised by a distal peripheral polyneuropathy (particularly of the legs) with paraesthesia, reduced knee jerks and other tendon reflexes, and progressive severe weakness with muscle wasting.
muscle wasting (dry beriberi)
Dry beriberi is characterised by a distal peripheral polyneuropathy (particularly of the legs) with paraesthesia, reduced knee jerks and other tendon reflexes, and progressive severe weakness with muscle wasting.
Risk factors
strong
chronic alcohol excess
malnutrition
Vitamin B1 deficiency may result from poor nutritional intake, specifically a low consumption of bread and other cereal-based foods. Neurological features (‘dry beriberi’) and high-output cardiac failure (‘wet beriberi’) may occur separately or together, and Korsakoff’s psychosis can be precipitated by carbohydrate administration in sub-clinically deficient subjects. Dietary intake of about 1 mg of thiamine per day, obtainable from whole-grain cereals, pulses, nuts, and red meat, prevents clinical deficiency.[38] Those at risk of deficiency include those who chronically abuse alcohol and people who follow extreme weight-loss diets for long periods without supplementation.[39]
staple diet of polished rice
The germ cells of whole-grains and seeds are rich in thiamine, but polished rice is deficient in thiamine. In countries, where the diet is based around polished rice, outbreaks of beriberi are common.[1][4][5] Rates of beriberi decrease when the food supply is enriched with thiamine or when non-polished rice is used.[5]
age <1 year in endemic thiamine deficient region
The risk of thiamine deficiency disorders is highest in the first year of life in regions where thiamine deficiency is common, especially in exclusively breastfed infants as the thiamine content of breastmilk is related to maternal thiamine status.[1]
refeeding/total parenteral nutrition
Thiamine is a co-factor in the metabolism of carbohydrates. Therefore, vitamin B1 deficiency should always be considered and treated before refeeding orally, enterally, or parenterally (including simple intravenous dextrose).[27][40] Inadequate thiamine supplementation in total parenteral nutrition can lead to vitamin B1 deficiency.[28]
hyperemesis gravidarum
There is an increased demand for thiamine during pregnancy from the fetus and the hypermetabolic state of pregnancy itself.[41] In women with hyperemesis gravidarum, the thiamine absorption rate is decreased significantly due to excessive vomiting and poor oral intake, with resulting symptomatic thiamine deficiency. Nausea, vomiting, and a loss of appetite are common, non-specific presenting symptoms of thiamine deficiency and overlap with symptoms of hyperemesis gravidarum such that early diagnosis is often missed.[9] Thiamine deficiency can result in Wernicke’s encephalopathy, a life-threatening condition that may lead to permanent cognitive deficit or maternal death in women with hyperemesis gravidarum if not recognised and adequately treated.[9]
recurrent vomiting/chronic diarrhoea
weak
obesity
Increased caloric intake leads to an increased load on metabolic pathways, in particular glucose metabolism, and an increased demand for micronutrients such as thiamine as enzyme cofactors.[10]Thiamine deficiency has been reported in 16%-47% of patients planning to undergo bariatric surgery for obesity.[10][11][12]
magnesium deficiency
Magnesium is a co-factor for thiamine-containing enzymes.[10] Thus, an adequate supply of magnesium is required in order for thiamine to function fully. Thus, an adequate supply of magnesium is required in order for thiamine to function fully. Magnesium deficiency may be acute secondary to increased loss, such as diarrhoea following bariatric surgery, or chronic, such as in patients with alcohol-related liver disease due to low dietary uptake, greater urinary secretion, and lower plasma albumin concentrations.[10][29]
HIV infection/AIDS
cancer and chemotherapy
The anorexia, nausea and vomiting, and, in some cases, malabsorption associated with malignancy place these patients at risk of vitamin B1 deficiency.[22] Gastrointestinal malignancies and haematological malignancies are particularly implicated.[22][23]
Some chemotherapeutic agents interfere with thiamine function.[22][24][25][26]
thiaminase- and thiamine antagonist-containing diet
Thiaminases break down thiamine in food, and thiamine antagonists can interfere with the absorption of thiamine. A diet rich in certain foods, such as fermented fish (source of thiaminase), betel nuts, tea, coffee, and red cabbage (sources of thiamine antagonists), can result in vitamin B1 deficiency.[30][31]
genetic mutation
Patients who match a well-defined clinical phenotype may have a genetic mutation that affects thiamine transport and metabolism.[32] Mutations in SLC19A2 (thiamine transporter-1), SLC19A3 (thiamine transporter-2), TPK1 (thiamine pyrophosphokinase), and SLC25A19 (mitochondrial thiamine pyrophosphate carrier) exhibit well-defined clinical phenotypes and are inherited in a recessive pattern.[32][33]
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