If less than 0.2 mg of thiamine per 1000 kcal (4.2 MJ) is consumed in the diet, the first symptoms of vitamin B1 deficiency may appear after only 4 to 10 days. Marginal thiamine deficiency is initially manifested by nonspecific symptoms, such as fatigue, weight loss, and confusional states. Clinical symptoms of thiamine deficiency include.
- Disturbances in carbohydrate metabolism – elevation of pyruvate and lactate levels in blood as a result of decreased pyruvate decarboxylation, (secondary) acidosis, decreased urinary thiamine excretion (normal >66 µg/24 hours, marginal 27-65, severe deficiency <27)
- In the acute form of marked thiamine deficiency, metabolic acidosis occurs clinically (disturbances in the acid-base balance due to the increase in organic acids, causing the pH of the blood to fall below 7.36) – possibly associated with heart failure
- Peripheral neuropathies – disease of the peripheral nervous system, neurological disorders, disorders in neuromuscular information transmission – especially in the extremities with the highest degree of activity.
- Muscular atrophy – muscle atrophy, progressive loss of muscle mass as well as strength, and impaired or abolished muscle function – accompanied by muscle weakness, muscle pain and cramps (calf cramps), involuntary muscle twitching, and increased vulnerability
- Tachycardia – cardiac arrhythmias with increased heart rate, sustained pulse acceleration to over 100 regular beats per minute, without an increased need for cardiac pumping
- Changes in the electrocardiogram
- Limitation of the performance
- Memory loss
- Psychological lability in the form of poor concentration, irritability, depression, and anxiety.
- Apathy – apathy, lack of excitability, as well as insensitivity to external stimuli.
- Sleep disturbances
- Loss of appetite [
- Anorexia nervosa
- Gastrointestinal disorders – nausea (nausea, nausea)
- Decrease in gastric juice secretion.
In rare cases, vitamin B1 deficiency results in a symptom complex of diabetes mellitus, anemia and deafness.Central nervous deficits occur only when brain vitamin B1 levels fall below 20% of normal. Thiamine concentrations in the heart, liver, and kidneys, as well as urinary excretion, decline much more rapidly than thiamine levels in the brain. BeriberiA severe persistent vitamin B1 deficiency manifests itself in the clinical picture of beriberi [4.1., 17]. Depending on the course of the disease and the involvement of other nutrients and vital substances (for example, protein deficiency), patients suffer from neurological deficits – polyneuropathies, skeletal muscle atrophy, cardiac dysfunction and weakness, and edema.Classic avitaminosis beriberi is divided into several forms. Atrophic beriberi (dry or polyneuritic form) – “dry beriberi”.
Neurological symptoms
- Degenerative polyneuropathies of the extremities (bilateral, symmetrical)
- Paresthesias – tingling, numbness, falling asleep of the limbs, cold and heat perception disorders.
- Eye tremor, double vision
- Memory disturbances
- Reflex disorders
- Suspended foot
- Cramps
- Burning Feet Syndrome – seizure-like, painful burning of the feet.
- Limb ataxia – neurological disturbance of the usual movement and balance regulation.
- Atrophy of limb muscles, muscle weakness.
- Paralysis
For the pathogenesis of atrophic beriberi, in addition to vitamin B1 deficiency, caloric restriction is essential. Exudative beriberi (wet or cardiovascular form) – “wet beriberi”.
Cardiovascular symptoms
- Cardiac arrhythmias
- Sinus tachycardia – increased heart rate to over 100 regular beats per minute originating from the sinus node (“pacemaker of the heart”).
- Cardiac enlargement
- Right dilation (beriberi heart) – dilation of the right side of the heart (affecting the atrium and ventricle) due to overdistension as a result of excessive filling caused by inhibited outflow from the hollow organs
- Pericardial effusion – abnormal accumulation of fluid due to inflammation, in which the volume of fluid in the pericardium may increase up to one liter, which is normally 20 to 50 ml
- Heart failure (cardiac insufficiency) – decreased pumping function of the heart resulting in insufficient supply of blood and oxygen to the body, may lead to blood stasis in the lungs and other organs
Other characteristics
- Pulmonary and peripheral edema (facial, lower extremities, trunk).
- Ascites (abdominal dropsy) – abnormal accumulation of fluid in the free abdominal cavity.
- Rarely lactic acidosis without edema (Shoshin disease) – increase in the level of lactate in the blood and a simultaneous decrease in blood pH, hyperacidity of the blood, due to the accumulation of lactic acid; in severe cases, lactic acidosis can lead to shock and failure of renal function.
- Orthopnea – shortness of breath or difficult breathing (dyspnea), which occurs in a horizontal position (in bed) and improves when the upper body is raised; frequent occurrence in conjunction with heart failure.
For the development of exudative beriberi, high carbohydrate intake and protein deficiency play a major role, in addition to vitamin B1 deficiency. Wernicke encephalopathy / Wernicke-Korsakov syndrome (cerebral form) according to Carl Wernicke and Sergei Sergeyevich Korsakov.
Neurological symptoms
- Nystagmus (“eye tremor“) – uncontrollable, rhythmic movements of an organ, usually the eyes.
- Double vision
- Ophthalmoplegia – eye muscle paralysis
- Cerebellar ataxia – neurological disorder of usual movement and balance regulation.
- Paralysis – complete paralysis of the motor nerves of a body part – Wernicke-Korsakow syndrome involves paralysis of the 6th cranial nerve [7, 9
- Polyneuropathy (burning feet syndrome).
- Reflex disorders
Other characteristics
- Psychoses – severe mental disorders associated with a temporary extensive loss of reference to reality; prominent symptoms include delusions and hallucinations.
- Memory loss
- Impaired consciousness, disorientation
- Apathy and somnolence (drowsiness with abnormal sleepiness).
- Hyperexcitability
- Vegetative disorders, such as hypotension (low blood pressure with insufficient blood flow), hypothermia (hypothermia), and hyperhidrosis (excessive sweat production)
Individuals with high alcohol consumption are at increased risk for developing Wernicke’s encephalopathy or Wernicke-Korsakow syndrome due to usually low thiamine levels (for example, due to low dietary vitamin B1 intake and malabsorption). Effects of alcohol on thiamine metabolism.
- Inhibition of transport of vitamin B1
- Blocking thiamine conversion to the active coenzyme thiamine pyrophosphate, which is particularly responsible for energy production
- High thiamine consumption, as vitamin B1 is required for biochemical alcohol degradation.
- Increased excretion via the kidney
Korsakow syndrome, unlike Wernicke’s encephalopathy or Wernicke-Korsakow syndrome, is not a consequence of vitamin B1 deficiency. It is a form of amnesia – memory impairment, lack of memory – occurring mainly in chronic alcoholics. Korsakow’s syndrome is mainly attributed to alcohol-related partial destruction of the diencephalon and limbic system, always affecting the hippocampus. Vitamin B1 deficiency, in addition to Wernicke’s encephalopathy and Wernicke-Korsakow syndrome, respectively, can lead to cardiomyopathy with dilatation of the right ventricle – disease of the heart muscle with significant dilatation of the right ventricle – and polyneuropathy in a chronic alcoholic. Infantile beriberi
This form of beriberi disease occurs in breastfed infants whose mothers have severe thiamine deficiency. Infantile beriberi manifests between 2 and 6 months of age and is associated with symptoms similar to those of the mother. Neurologic symptoms
- Convulsions due to increased intracranial pressure (increased intracranial pressure).
Cardiovascular symptoms
- Tachycardia
- Heart failure
Other characteristics
- Nausea, vomiting
- Diarrhea
- Cyanosis – blue discoloration of the skin, especially on the lips and fingers (the discoloration occurs when less than 35% of hemoglobin (red blood pigment) is oxygenated).
- Colic – attack of violent cramp-like pain caused by the spasmodic contraction of a hollow organ (for example, intestine, ureter, gallbladder).
- Dyspnea – shortness of breath or difficult breathing.
- Weakness in drinking
- Apathy
- Restlessness
Metabolic disorders
Since some enzymes are vitamin B1-dependent, congenital thiamine deficiency may result in enzyme defects due to insufficient or absent synthesis Enzyme deficiency eventually leads to metabolic disorders [4.1. ].Deficiency of thiamine-dependent enzymes results in the following hereditary enzymopathies Leucinosis – maple syrup disease.
- Impaired degradation of branched-chain amino acids, leading to the accumulation of their keto analogs.
- In the mild or intermittent form of leucinosis, the residual activity of dehydrogenase is up to 40% and in the more common classical form is about 2% of normal
- The course of the mild or intermittent form can be improved by administration of 10 to 150 mg of vitamin B1 per day and simultaneous restriction of protein intake
- Without any treatment, leucinosis can cause severe neurological changes, physical and mental developmental abnormalities, and in severe cases, death in patients [4.1].
Leigh syndrome – necrotizing encephalomyelopathy.
- Presumed to be a genetic disorder of thiamine triphosphate transferase with impaired formation of thiamine triphosphate, in some cases in combination with weakened keto acid dehydrogenase (TTP).
- Patients suffer from neurological deficits, nystagmus and paralysis of the external eye muscles, convulsions, ataxia, as well as confusional states resembling Wernicke’s encephalopathy
- For therapy, vitamin B1 and lipid-soluble derivatives (fursultiamine) should be administered in doses up to the gram range; bicarbonate administration and a low-carbohydrate diet should reduce the concomitant lactic acidosis [4.1].
Congenital lactic acidosis
- Defect of pyruvate dehydrogenase or partial enzymes of this complex.
- Clinical symptoms resemble those of Leigh syndrome, although clear differentiation of these enzymopathies is often not possible
- Both clinical symptoms and acidosis could be influenced by thiamine administration only in isolated cases
Thiamine-responsive megaloblastic anemia.
- The cause of this metabolic disorder is still unclear; it is thought to be a disorder of thiamine transport possibly affecting only individual tissues
- Peculiar combination of anemia with insulin-dependent diabetes mellitus and inner ear deafness.
- To improve anemia, the patient needs about 20 to 100 mg of vitamin B1 daily, only in exceptional cases diabetes mellitus also improves.
