Clinical Manifestations and Pathogenesis of Keshan Disease

Keshan disease is a severe cardiomyopathy caused by a deficiency of selenium, an essential trace mineral critical for antioxidant defense and immune function. Named after Keshan County in China, where it was first identified, this disease is prevalent in regions with selenium-deficient soils, such as parts of China, Africa, and certain areas in Europe and Asia. In these regions, the dietary intake of selenium is often insufficient, making the population vulnerable to this life-threatening condition.

The symptoms of Keshan disease vary depending on its classification into acute, subacute, chronic, or latent forms. Acute Keshan disease manifests as a sudden onset of severe cardiogenic shock, acute heart failure, and fatal arrhythmias. Early warning signs include nausea, dizziness, chills, shortness of breath, and a marked loss of appetite. Subacute Keshan disease typically presents with congestive heart failure, cardiogenic shock, and significant heart enlargement, which often progresses rapidly.

Chronic Keshan disease develops over time and is characterized by persistent symptoms, including palpitations, dyspnea (difficulty breathing), productive cough sometimes accompanied by hemoptysis (coughing up blood), pain in the right upper abdominal quadrant, peripheral edema, and progressive cardiomegaly (heart enlargement). These symptoms indicate long-term damage to the heart muscle, severely affecting its ability to pump blood efficiently.

Latent Keshan disease exhibits milder symptoms such as fatigue, dizziness, minor palpitations, and slight heart enlargement. While less dramatic than acute or chronic forms, latent Keshan disease poses significant risks if selenium deficiency persists, potentially escalating to more severe stages.

The pathogenesis of Keshan disease is linked to a combination of selenium deficiency and the presence of coxsackievirus infections, which exacerbate oxidative stress and myocardial damage. Selenium plays a vital role in the function of glutathione peroxidase, an enzyme that protects cells from oxidative damage. Without adequate selenium, the heart muscle becomes vulnerable to free radical injury, leading to structural and functional impairments.

Preventing and managing Keshan disease involves ensuring sufficient selenium intake through dietary sources like nuts, seafood, and organ meats, or supplementation where necessary. Public health interventions, such as soil enrichment programs and targeted supplementation campaigns, have significantly reduced the prevalence of Keshan disease in affected regions, underscoring the importance of addressing micronutrient deficiencies in global health initiatives.
Clinical Manifestations and Pathogenesis of Keshan Disease

Keshan Disease: A Silent Cardiac Threat

Keshan disease, a severe cardiomyopathy linked to selenium deficiency, was first identified in Keshan County, China, where its prevalence highlighted the critical role of trace elements in human health. Selenium, an essential micronutrient, is vital for antioxidant defenses and immune function. Its deficiency compromises heart muscle integrity, leading to progressive cardiac dysfunction.

The disease manifests in four phases: acute, subacute, chronic, and latent, each presenting distinct clinical features. In the acute phase, patients may experience sudden onset of cardiogenic shock, characterized by drastically low blood pressure and inadequate blood flow to organs. This is often accompanied by dizziness, severe nausea, projectile vomiting, and dyspnea. The subacute phase is marked by more gradual symptoms, including malaise, facial edema, and heart dilation, which can progress to cardiac shock.

Chronic Keshan disease presents with long-term complications such as persistent palpitations, chronic cough (sometimes hemoptysis), and fluid retention leading to edema. Enlargement of the heart and oliguria are also common, indicating compromised cardiac and renal function. Latent Keshan disease is milder, with symptoms like fatigue, mild palpitations, and slight heart enlargement, often unnoticed until progression occurs.

The global significance of selenium in preventing Keshan disease has prompted extensive research. Regions with selenium-deficient soils, such as parts of China, Siberia, and New Zealand, have reported higher incidences. However, with improved agricultural practices and dietary selenium supplementation, cases have significantly declined. Despite this, sporadic outbreaks still occur, especially in vulnerable populations with limited access to balanced diets.

Early diagnosis is pivotal. Selenium supplementation, often coupled with supportive therapies like antioxidants and heart medications, can reverse early-stage symptoms and prevent progression. Public health strategies, including food fortification and community health education, have proven effective in mitigating risks.

In summary, Keshan disease underscores the importance of micronutrients in cardiovascular health. Its prevention hinges on early detection, adequate selenium intake, and public health interventions. Addressing selenium deficiency remains crucial in safeguarding vulnerable populations from this potentially fatal condition.
Keshan Disease: A Silent Cardiac Threat

Hereditary Hemochromatosis Overview

Hereditary hemochromatosis (HH) denotes a group of uncommon genetic disorders characterized by the buildup of iron in various organs, including the skin, heart, liver, pancreas, pituitary gland, and joints.

Because the body lacks the capability to enhance iron excretion, an excess of iron can accumulate, resulting in abnormal storage that gradually becomes toxic, causing harm to tissues and organs.

Symptoms of hemochromatosis include fatigue, weight loss, joint discomfort, a bronze or grey skin tone, abdominal pain, and a reduced sex drive. Typically, these symptoms surface in adulthood, often after a significant surplus of iron has amassed in the body. Most individuals do not experience symptoms until later in life, typically after the age of 40 in men and 60 in women.

As the condition advances, affected individuals may develop arthritis, liver complications such as cirrhosis or cancer, diabetes, heart irregularities, and skin discoloration. The root cause of hemochromatosis lies in a faulty gene, commonly the HFE gene, which can be inherited from parents and affects the body's ability to absorb iron from food.
Hereditary Hemochromatosis Overview

Symptoms of manganese deficiency

Manganese is a naturally occurring element and an essential mineral nutrient. Manganese deficiency is very rare in humans.

Manganese helps the body form connective tissue, bones, blood clotting factors, and sex hormones. Manganese serves as an essential part of important enzymes, including mitochondrial superoxide dismutase. It also plays a role in fat and carbohydrate metabolism, calcium absorption, and blood sugar regulation.

A person that does have a deficiency in manganese could experience the following symptoms:
*Bone demineralization
*Slow or impaired growth
*Low fertility
*Abnormal metabolism of carbohydrate and fat
*Impaired glucose tolerance, a state between normal glucose maintenance and diabetes

Other symptoms include: skin rashes, hair depigmentation, decreased serum cholesterol, and increased alkaline phosphatase activity in men; and altered mood and increased premenstrual pain in women.

Rich dietary sources of manganese include nuts and seeds, wheat germ and whole grains (including unrefined cereals, buckwheat, bulgur wheat, and oats), legumes, and pineapples.
Symptoms of manganese deficiency

Symptoms of Wilson's disease

Wilson disease (WD) is an autosomal recessive inherited disorder caused by dysfunction of the copper transporter ATP7B, which is expressed mainly in hepatocytes and is critical for hepatic copper homeostasis. Subsequent copper accumulation, first in the liver but ultimately in the brain and other tissues, produces protean clinical manifestations that may include hepatic, neurological, psychiatric, ophthalmological, and other derangements,

It has been estimated that there are ~600 cases of Wilson’s disease in the United States and that ~ 1% of the population are carriers.

Wilson’s disease may present symptomatically at any age, although the majority presents between ages 5 and 35. The youngest patient reported with cirrhosis due to Wilson’s disease was 3-years-old. Many patients have a combination of symptoms. WD often presents in children as chronic liver disease with abnormal liver tests. Liver pathology ranges widely, from hepatic steatosis to acute and chronic hepatitis to cirrhosis. As WD progresses, many patients develop complications of portal hypertension and liver failure. Acute liver failure (ALF) due to WD develops in about 5% of patients.

Patients with WD are more likely to present with neurologic or psychiatric manifestations in their second or third decade of life. Some patients have symptoms of liver disease as well. Neurologic symptoms may be subtle or rapidly progressive, leading to severe disability over weeks to months.

The clinical hallmark of Wilson’s disease is the Kayser–Fleischer ring, which is present in 95% of patients with neurologic symptoms and somewhat over half of those without neurologic symptoms. In children presenting with liver disease, Kayser–Fleischer rings are usually absent. Kayser–Fleischer rings are caused by deposition of copper in Desçemet’s membrane of the cornea.
Symptoms of Wilson's disease

Dietary deficiency of chloride

The element chlorine is a poisonous gas. When chlorine reacts with sodium or hydrogen, however it forms the negative chloride ion. Chloride, an essential nutrient, is required in the diet.

Chloride accounts for approximately 0.2% of the body’s weight and it is widely distributed throughout tissues.

Chloride losses may occur in conditions such as heavy sweating, chronic diarrhea, and vomiting. Because the normal intake and output of chloride from the body parallels that of sodium, conditions leading to a sodium deficiency also can lead to a chloride deficiency.

Severe deficiency may result in alkalis (an excess of alkali in the blood), which is characterized by slow and shallow breathing, listlessness, muscle cramps, loss appetite and occasionally convulsion.
Dietary deficiency of chloride 

Sodium depletion and water balance in human body

The human body is made up of 50 – 60% water by weight. Under normal circumstances, the amount of water taken into the body, and lost is equal over a period of time. In such a condition, the person is said to be in water equilibrium.

The results of sodium depletion are closely related to the state of water balance.  If only sodium is lost and water is retained, serum sodium concentration eventually will decrease, as when water only is replaced following excessive sweating.

As a result water will migrate into the cells and symptoms of water intoxication develop: loss of appetite, weakness, mental apathy and muscle twitching.

If sodium loss is accompanied by water loss, symptoms of extra cellular fluid depletion develop: low blood volume, high hematocrit, collapse of veins, low blood pressure and muscle cramps. Most cases of dehydration seen in medical practice result from excessive loss of fluid from the gastrointestinal tract as a consequence of vomiting or diarrhea.

Following a reduction in body water, the only way to increase body water levels is to ingest fluid. This is largely controlled by the sensation of thirst although deviations in body water are not well detected by the thirst response. The thirst response is a complex concentration of physiological, psychological and behavioral factors.
Sodium depletion and water balance in human body

Manganese toxicity

Toxicity of manganese compounds appears to depend upon type of manganese ion presents and the oxidation state of manages.

It has been suggested that manganese cations are more toxic than the anion forms. In 1901 research showed that manganese toxicity could result in neurological damage in humans.

However, it was not until a series of reports in the 1930s and 1940s describing a high incidence of manganese toxicity in manganese mine workers that manganese toxicity was recognized as a significant health workers. Chronic inhalation exposure of humans to high levels may result in a syndrome called manganism and typically begins with feelings of weakness and lethargy and progresses to other symptoms such as gait disturbances, clumsiness, tremors, speech disturbances, a mask-like expression, and psychological disturbances.

Additionally, individuals with liver failure are at greater risk for toxicity because manganese homeostasis is maintained largely by the liver through excretion in the bile.

Manganese toxicity secondary to liver failure is characterized by manganese accumulation within the liver and other organs such as the brain; accumulation in the brain results in neurologic abnormalities.

Psychological changes including mental irritability, headaches, nervousness, compulsive actions, and hallucinations can occur.
Manganese toxicity 

Keshan disease

Keshan disease an endemic cardiomyopathy that was first described in Keshan County, Heilongjiang Province, Northeast China in 1935. Keshan disease is a cardiomyopathy that may be exacerbated by viral infections.

The heart pathology is characterized by foci or necrosis throughout the myocardium.  Keshan disease occurs with symptoms of congestive heart failure or less frequently, as sudden death or stroke from diffuse cardiac thromboses. Symptoms include ECG changes such as right branch block and cardiogenic shock.

Keshan disease was predominantly found in children between 2 to 10 years old, and to a lesser extends women of child bearing age.

The epidemiology of Keshan disease suggested an environmental factor because of the distribution of the disease occurred in a belt-like fashion from northeast to southwest China and in very specific hilly and mountainous areas. It is the selenium poor areas of the iodine deficient band of land.

Widespread selenium supplementation of the population in affected areas has caused a dramatic decrease in the incidence of Keshan disease.
Keshan disease

Toxicity of zinc

In humans, most of the body’s zinc is in the skeletal muscle (about 60%) and one third in the bone, skin, liver, brain, kidneys and the heart have small total amounts in this regard. Excessive intakes of zinc cause toxicity.

Zinc has low human toxicity by the oral route, but high levels can cause gastrointestinal distress. An acute zinc toxicity (such as from 4 g of zinc gluconate, which provides 570 mg of elemental zinc) produces some of the following symptoms: metallic taste, headache, weak heart beat, nausea, vomiting, epigastric pain, abdominal cramps and bloody diarrhea.

Tachycardia, hemolytic anemia, pancreatitis, renal damage and death have been reported on this occasion.

Long term oral intakes of zinc at levels of 18,5 to 25 mg/day can interfere with copper absorption and intakes 10 to 30 items the RDA can impair immune responses and decrease serum high density lipoprotein.

The most common sources of zinc poisoning in human are metal fumes, and illness arising the ingestion of acidic foods prepared in zinc galvanized containers. The inhalation of zinc phosphide or phosphine gas also results in acute toxicity.
Toxicity of zinc

Copper deficiency symptoms

Copper is an essential trace mineral. Copper is necessary for proper absorption of iron in the body, and it is found primarily in foods containing iron.

Copper deficiency can produce various symptoms, including diarrhea, inefficient utilization of iron and protein, and stunted growth.

The most frequent symptoms of copper deficiency are anemia, neutropenia, and skeletal defects while less frequent symptoms are lack of pigmentation, impaired growth, increased incidence of infections and abnormalities of glucose and cholesterol metabolism, defective fatty-acid metabolism and abnormalities in the cardiovascular system.

Possible manifestations, in addition to the features of severe deficiency, are conditions such as arthritis, arterial disease, and neurological effects.

Infants are more susceptible to overt symptoms of copper deficiency that are any other population group.

Among the predisposing factors of copper deficiency are prematurity, low birth weight, and malnutrition, especially when combined with feeding practices such as cow’s milk or total parenteral nutrition.

The development of nerve, bone and lung tissue can be impaired and the structure of these body parts may be altered.
Copper deficiency symptoms

Signs and symptoms of Hyponatremia

Hyponatremia is the most common electrolyte abnormality and is defined as plasma sodium concentration of less than 135 mmol/ L.

Hyponatremia results from an excess of water relative to sodium, regardless of the volume status. Young adult patient appears to tolerate a specific level of hyponatremia belter than does the older patient.

Symptoms may include headache, lethargy ataxia and hypertension. Other symptoms than accompany severe hyponatremia include loss, appetite, nausea, vomiting, cramps, weakness, altered level of consciousness, coma, and seizure.

In the great majority of cases, hyponatremia is mild as asymptomatic and generally does not require aggressive treatment.

Hyponatremia is associated with substantially increased mortality, both as a direct effect of hyponatremia and because hyponatremia is associated with severe systemic disease.

Severe hyponatremia of rapid inset may lead to brain edema and herniation and therefore requires rapid treatment. Cheyne-Stokes respiration may be a hallmark of severe acute hyponatremia.
Signs and symptoms of Hyponatremia 

What are symptoms of hypophosphatemia?

Hypophosphatemia occurs when the serum phosphorus level falls below 2.5 mg/dl. Signs and symptoms of hypophosphatemia depend on the severity, associated deficiencies and underlying illness.

Mild to moderate hypophosphatemia is often asymptomatic and major clinical sequelae are usually seen only in severe hypophosphatemia.

Hypophosphatemia affects the musculoskeletal, central nervous system, cardiac and hematologic systems. With hypophosphatemia, muscle weakness is the most common symptom. Other symptom may include diplopia, malaise, and anorexia. The patient may experience a weakened hand grasp, slurred speech or dysphagia and also may develop myalgia.

Hypophosphatemia can cause rhabdomyolysis. This may be asymptomatic, manifested only by increased serum muscle enzyme levels or may cause severe muscle pain and weakness and acute renal failure. 

Osteomalacia, loss of bone density and bone pain may occur with prolonged hypophosphatemia and can result in pathological fractures.

Respiratory insufficiency is common among severely hypophosphatemia patients. Respiratory failure may result from weakened respiratory muscles and poor contractility of the diaphragm.

Hypophosphatemia may also cause hemolytic anemia because of changes in the structure and function of red blood cells. Hypophosphatemia results in impaired production of 2,3-DPG in the erythrocyte, causing a leftward shift of the oxyhemoglobin dissociation curve and decreased tissue oxygen delivery.

Hypophosphatemia cause lack of ATP results in decreased leukocyte production, making the patient susceptible to infection.

Chronic hypophosphatemia also effects platelet function, resulting in bruising and bleeding, particularly mild GI bleeding.
What are symptoms of hypophosphatemia?

Manganese toxicity symptoms

Manganese is widely distributed in the biosphere: it constitutes approximately 0.085% of the Earth’s crust, making it the twelfth most abundant element. Exposure to high levels of oral, parental and air manganese may result in toxicity.

Manganese toxicity in humans is primary a concern for those exposed to high airborne concentration in the workplace, especially industrial workers and miners.

Severe neurological damage has been observed in inhabitants of Groote Eylandt, an island in the Gulf of Carpentaria off the north coasts of Australia which contains one of the world’s richest manganese mines.

In addition to neural damage, reproduction and immune dysfunction, nephritis, testicular damage, pancreatitis, lung disease, and hepatic damage can occur with manganese toxicity, though the frequency of these disorders in unknown. Manganese toxicity can result in a permanent neurological disorder known as manganese with symptoms that include tremor, difficulty walking and facial muscle spasms.

In the milder form, toxicity is expressed by hyperirritability, violent acts, hallucinations, disturbances of libido and coordination.

Cases of manganese toxicity in humans have reported only for adults; however, it has been suggested that infants may be at high risk for manganese toxicity due to a high absorptive capacity for the element and/or an immature excretory pathway for it.

Additionally, individuals with liver failure are at greater risk for toxicity because manganese homeostasis is maintained largely by lover though excretion in the bile.

The symptoms of manganese toxicity may appear slowly over months and years.
Manganese toxicity symptoms

Symptomatology of magnesium deficiency

Since magnesium is present in most common foodstuff, low dietary intakes of magnesium are associated with general nutritional insufficiency.

Marked symptoms of magnesium deficiency appeared and the early symptoms of magnesium deficiency can include fatigue, anorexia, irritability, insomnia and muscle tremors or twitching.

Symptoms of a deficiency principally occurs in the nervous system, skeletal muscles, gastrointestinal tract and cardiovascular system.

Symptom associated with the central nervous system often begin with apathy, apprehension, decreased learning ability, confusion, poor memory, depression, and reduced ability to concentrate.

Neuromuscular hyperirritability may be the most common presenting problem in magnesium depleted patients. Cardiac arrhythmias are a serious complication of magnesium depletion.

Symptoms associated with gastrointestinal tract: intestinal malabsorption, severe vomiting, diarrhea or other causes of intestinal loss.

Deficiency is more likely in those who eat processed food diet. Deficiency is also more common when magnesium absorption is decreased, such as after burns, serious injuries or surgery and in patients with diabetes, liver disease or malabsorption problems, and when magnesium elimination is increased as in people who use alcohol, caffeine or excess sugar.
Symptomatology of magnesium deficiency

Deficiency of Chromium

Deficiency of Chromium
Researchers estimate that two out of every three Americans are hypoglycemic, pre-hypoglycemic or diabetic. The ability to maintain normal blood sugar levels is jeopardized by the lack of chromium in our soil and water supply and by a diet high in refined white sugar, flour and junk foods. A number of human and animal studies have found that chromium supplements can improves insulin sensitivity and blood sugar in the face of insulin resistance, elevated blood sugar levels, impaired glucose tolerance and diabetes.

A deficiency of chromium can lead to anxiety, fatigue, glucose intolerance, (particularly in people with diabetes), inadequate metabolism of amino acids and an increased risk of arthrosclerosis. Excessive intake (the level depends upon individual tolerance) can lead to chromium toxicity, which has been associated with dermatitis, gastrointestinal ulcers, and kidney and liver impairment.

Supplemental chromium is best absorbed by the body when it is taken in a form called chromium picolinate (chromium chelated with picolinate, a naturally occurring amino acid metabolite). Picolinate enables chromium to readily enter into the body’s cells, where the mineral can then help insulin do its job much more effectively.
Deficiency of Chromium