Thiamine deficiency is a nutritional disorder that stems from the lack of thiamine, also known as vitamin B1. It is available in many foods and thiamine plays a key role in cellular metabolism. Individuals with severely low levels of this vitamin develop consequences that involve the brain, heart, and nerves.
While there are known sequelae in these patients, they may initially present with nonspecific symptoms such as anorexia, abdominal discomfort, fatigue, irritability, and precordial pain. Other early signs may include memory loss and sleep changes.
There are two components of neurologic complications which include peripheral neurologic deficits as well as central impairment. The former manifests in a stocking-glove distribution especially in the lower extremities. Specifically, the clinical picture consists of toe paresthesias, burning in the feet, calf muscles cramping, leg pain, and plantar dysesthesias. Persistent thiamine insufficiency leads to the progression of these symptoms as well as upper extremity involvement.
In very young infants receiving low thiamine breast milk, the consequences include rapid onset of heart failure and aphonia. Furthermore, they characteristically exhibit a loss of deep tendon reflexes.
In terms of the neurologic exam, remarkable findings include calf muscle tenderness and decreased vibratory sense in the toes. Additionally, these patients may encounter trouble with changing positions between squatting and standing.
A mental status exam is crucial as it reveals evidence of Wernicke-Korsakoff syndrome in those affected with it.
Patients with cardiovascular involvement are notable for features such as tachycardia, wide pulse pressure, evidence of edema, and other related findings. Cases with severe vasodilation can result in shock.
The clinical assessment consists of retrieving the medical and social history (including dietary and alcoholic intake) of the patient, performing a physical exam with a focus on cardiovascular and neurologic systems, and observing a therapeutic response to thiamine. It is important for a clinician to develop a high index of suspicion based on the understanding of the risk factors as well as the patient's history and physical exam.
The confirmatory method for diagnosis of this nutritional disorder is the successful response to thiamine correction. Note that this observation along with electrolyte measurements will help exclude differential diagnoses that present similarly to thiamine deficiency such as diabetes, vitamin B12 deficiency, and metal toxicities.
In cases with uncertainty, levels of serum thiamine, pyruvate lactate, alpha-ketoglutarate, and glyoxylate, as well as urinary thiamine can be obtained.
With regards to Wernicke-Korsakoff syndrome, the recommended regimen is treatment with 50 to 100mg thiamine intravenous (IV) or intramuscular (IM) to be administered twice a day for several days. This is followed by 10mg to 20mg daily until a successful response is achieved. Korsakoff psychosis may take up to 3 months for recovery.
Intake of the offending substance, alcohol, should be discontinued while the clinician monitors for alcohol withdrawal syndrome in these patients. Also, since alcohol cessation is difficult, the clinician should provide alcoholic patients with educational and community resources to help tackle this challenge.
Cardiovascular disease should also be addressed promptly in order to control the current manifestations and prevent further deterioration.
Finally, patients should consume a well-balanced diet with adequate levels of vitamins including thiamine. Furthermore, other B vitamins and water-soluble vitamins should be supplemented since deficiencies of these vitamins often coexist with thiamine deficiency.
While this easily treatable vitamin abnormality can be life-threatening, it is associated with a good prognosis if therapy is initiated in the early stage of the disease. Once Wernicke-Korsakoff syndrome manifests, this severe degree of damage can be irreversible. Although improvement can occur with thiamine administration. Specifically, Korsakoff psychosis is improved in 1 to 3 months although the neurologic features do not typically completely recover. Furthermore, ophthalmoplegia resolves within a day of treatment.
With regards to cardiovascular complications, thiamine replacement produces symptomatic improvement of acute cardiac failure within 12 hours of therapy while function and size are usually restored in 24 to 48 hours.
This nutritional disorder has an impact on the quality of life since it produces a state of low energy. Therefore, patients struggle with accomplishing normal daily activities.
Thiamine deficiency is more common in geographical areas with high consumption of food sources that are lacking in thiamine. Examples include highly processed foods, white cereals, polished white rice, white sugar and wheat flour. Additionally, foods that contain thiaminase such as raw shellfish, raw freshwater fish, and milled rice can lead to a significant deficiency in this vitamin. Furthermore, food with anti-thiamine factors like betel nuts, coffee, and tea can destroy thiamine. In contrast, poor intake of food rich in thiamine such as meat, fish,and vegetables also contribute to this nutritional disorder .
There are patient profiles that increase the risk for this condition, which tends to be those with a history of alcoholism, starvation, or gastric bypass surgery, with the latter resulting from diets restricted to reduced calories (600 to 900 kcal/day)   . Furthermore, patients receiving parenteral nutrition lacking thiamine replacement are at risk for developing this nutritional abnormality . as well as persons receiving peritoneal dialysis without thiamine correction, and patients treated with intravenous fluids containing high levels of glucose.
Additionally, this disorder occurs in individuals with chronic alcohol consumption, those who are severely malnourished, as well as persons with health states conducive to low-calorie intake and special diets.
Thiamine, an essential co-factor in key metabolic pathways, is found in all cells. Physiologically diminished levels of this vitamin result in the impairment of thiamine-dependent enzymes and mitochondrial function. Hence, the effects of thiamine shortage are devastating on all organs, especially that of the brain . as neuronal death is a consequence of energy compromise at sites of increased metabolic requirements and thiamine turnover . Specifically, this insufficiency leads to the degeneration of the mammillary bodies, thalamic nucleus, periaqueductal gray matter ., cerebral cortex, hippocampus, the fornices, and the areas surrounding the third ventricle . This disorder also affects the structures on the floor of the fourth ventricle including the cerebellar vermis, vestibular nuclei, and the ocular motor nuclei .
Since the memory circuits are affected ., alcoholics are predisposed to develop Wernicke-Korsakoff syndrome. Specifically, this complication is a combination of Wernicke encephalopathy and Korsakoff psychosis. The former likely occurs in response to an acute deficiency of thiamine superimposed on the long-term deficit of the vitamin while the latter stems from chronic deprivation. Frequently, Korsakoff syndrome is preceded by Wernicke encephalopathy.
Additionally, there is a decline in cerebral perfusion as thiamine is a key factor in cerebral metabolism.
The cardiac structure and function can undergo serious alterations as a result of fluid entering the interstitial spaces resulting in the swelling of the muscle fibers and the dilation of the heart. Furthermore, peripheral edema secondary to vasodilation is likely to occur as well as increased arteriovenous blood shunting. These events culminate into high output cardiac failure.
Education is available to guide the public about adequate nutrition. It is imperative that people consume nutritionally balanced meals including the daily requirements of vitamins.
Those at risk for this condition such as alcoholics and anorexic individuals should be encouraged to address these serious issues to prevent thiamine deficiency and the many other serious health risks associated with these starved states.
Additionally, since patients post-gastric bypass typically consume low-calorie diets, they should be receiving thiamine supplementation. Furthermore, patients receiving parenteral nutrition also warrant thiamine therapy.
Finally, since this disorder can cause infant death, pregnant and lactating mothers should be educated about thiamine-rich diets and their effects on their infants.
Thiamine deficiency emerges primarily from the lack of thiamine, which is attributed to either the scarcity of this vitamin in available food or inadequate intake of thiamine-enriched foods. Additionally, states such as chronic alcoholism, starvation and other health related conditions are chief risk factors for developing this vitamin deficiency.
Since thiamine is critical for metabolism, its insufficiency is detrimental to the normal function of the brain, heart, and nerves. Severe complications include Wernicke encephalopathy and Korsakoff psychosis, which arise particularly in alcoholics  . that manifest as cerebral impairment. Further sequelae of thiamine deficiency include peripheral nerve deficits, acute heart failure, and infantile death.
Diagnosis is achieved through careful assessment of the patient's history and risk factors, clinical picture (which should raise suspicion for this condition), and physical exam. Furthermore, the diagnosis is confirmed by the patient's successful therapeutic response to thiamine replacement. In cases where the diagnosis is inconclusive, there are blood and urine tests that can confirm the diagnosis.
Thiamine supplementation is the key treatment for these patients. It is initially administered in high doses and then tapered after a few days. Since it is highly likely that other vitamins abnormalities are also present, these should be corrected as well. Finally, another component in the management plan is alcohol cessation among alcoholics.
What is thiamine?
Thiamine is another name for vitamin B1, which is found in many foods. Thiamine is used in all cells and is required for the metabolism of carbohydrates and the production of energy. It is necessary for normal functioning of the brain, heart, muscle and the nerves.
Thiamine is found in meat, fish, vegetables, etc.
Who develops thiamine deficiency?
Individuals with low thiamine diets tend to develop this condition. The following foods have low amounts of thiamine:
Foods that contain enzymes and factors that degrade thiamine can cause this as well. Examples include:
Individuals with the following conditions can develop thiamine deficiency:
What are the signs and symptoms of thiamine deficiency?
Early symptoms may include:
Symptoms of peripheral nerve include:
Signs of Wernicke-Korsakoff syndrome include:
Signs of heart failure include:
How is this diagnosed?
The clinician will obtain a full history of the patient including details about the alcohol and food consumption. Also, the clinician will examine the patient thoroughly. The clinical picture will be indicative of the thiamine deficiency.
The best method to confirm this condition is by treating it with thiamine and achieving improvement.
There are blood and urine tests that can be performed to confirm the condition if necessary.
How is this treated?
Replacing thiamine is the main treatment of this deficiency. The first few days will require high amounts of thiamine which can then be decreased to lower doses. Also, since these patients may lack other vitamins, those should be corrected as well.
Note that alcohol should be stopped altogether. Furthermore, since quitting alcohol intake is difficult and challenging, these individuals should be receiving resources to help them through their journey.
How can this be prevented?
Public health education should include information on healthy diets and nutritious meals. Pregnant and breastfeeding women should also receive education on what constitutes a thiamine-rich diet and how this impacts their infants.
Kessels RP, Kortrijk HE, Wester AJ, et al. Confabulation behavior and false memories in Korsakoff's syndrome: role of source memory and executive functioning. Psychiatry and Clinical Neurosciences. 2008; 62(2):220-5.