Usually, when we are sick with an illness or disease, we are aware of it and are doing everything we can to get better. But some serious diseases are often referred to as ‘silent killers’ because of their lack of obvious symptoms, which causes a delay in detection that can prove to be fatal. Here are 10 silent-killer diseases you should know about.

1. High Blood Pressure

High blood pressure is also known as hypertension, and it’s a common, very dangerous health issue. High blood pressure occurs when the pressure of the blood in vessels is higher than it should be, putting added pressure on the heart and arteries. This added pressure can increase the risk of cardiovascular diseases like stroke and heart attacks, as well as kidney failure.

Blood pressure will rise and fall naturally during the day, depending on what we’re doing at the time. When we’re relaxed and calm, the pressure is lower, but it rises due to things like exercise, excessive alcohol intake, smoking, age, sedentary lifestyle, obesity, age, diabetes and too much salt in the diet. Blood pressure that is too high will affect blood flow to the organs, which increases the chance of developing other health issues like eye disease and erectile dysfunction.

High blood pressure is known as a silent killer because most people with this condition will have no symptoms and feel generally healthy. If blood pressure is extremely high, a few people may experience dizziness, headache or sudden effects like chest pain or stroke. Because blood pressure rises and falls so frequently, it can be difficult to diagnose. Generally, if your blood pressure is higher than normal on three separate occasions, you have high blood pressure.

To treat high blood pressure, it’s important to lead a healthy, active lifestyle. Regular physical activity, quitting smoking, losing weight, limiting alcohol intake and improving your diet to include more fresh fruit and vegetables are some steps you can take to reduce high blood pressure. Some people may also require medication to help reduce blood pressure. If you think you may be at risk of high blood pressure, it’s important to see your doctor as soon as possible.

2. Diabetes

Diabetes is one of the biggest health issues of this century. It’s a serious condition that affects the entire body, and if it’s not treated or managed effectively it can have a significant impact on the quality of life, and reduce life expectancy. Though there is currently no cure for diabetes it can be controlled by learning about the condition, and how to manage it successfully.

Diabetes is a chronic disease that is characterized by high levels of sugar (glucose) in the blood. These levels are regulated by insulin, a hormone that is produced by the pancreas gland. When there’s a problem with insulin production, like the pancreas is unable to make enough, or the body can’t use it correctly, diabetes can occur. There are three main types of diabetes, type 1, type 2 and gestational diabetes, which can occur in pregnant women.

When our bodies are functioning properly, any sugar that is consumed in food is converted into energy, and insulin is essential in this conversion. Diabetics are not able to turn sugar into energy, and it instead stays in the blood, leading to high blood glucose levels. Patients with type 1 diabetes will usually be diagnosed quickly, because the symptoms are very sudden and can be potentially fatal. Symptoms of type 2 diabetes are often confused with other, less serious conditions, as they include things like being more thirsty than usual, feeling lethargic, itching skin, blurred vision, mood swings, headaches, leg cramps and weight gain.

If left untreated, diabetes can cause serious health complications like kidney damage, eye damage, nerve damage, heart disease, sexual difficulties and circulation problems. Currently, there is no cure for diabetes, but it can be managed effectively to prevent further complications. Treatment includes daily insulin injections, a healthy diet, self-monitoring blood sugar levels, adequate physical activity, medication, weight management and regular check-ups with the doctor.

3. Coronary Artery Disease (CAD)

Coronary artery disease (CAD) is a condition of the heart that occurs when the arteries get narrower, leading to a reduction in blood flow to the heart. This is usually caused by a condition known as atherosclerosis. Even from a young age, fatty material (known as plaque) begins to build up on the lining of the artery walls. Our bodies are quite adept at clearing up the inflammation caused by plaque, and it can take many years before any negative effects can be seen from plaque in the arteries. However, it builds up over time and eventually narrows the arteries so much that it causes discomfort and pain.

The cause and risk factors of atherosclerosis leading to coronary artery disease can vary, and are considered either controllable or uncontrollable. Controllable risks are things like high blood pressure, high cholesterol levels, diabetes, lack of physical activity and lifestyle choices like smoking and excessive drinking. Uncontrollable risks are things like gender, heredity and age.

Coronary artery disease is known as a silent killer because often, people won’t know they have a problem until they’re experiencing chest pain (angina), or suffering a heart attack or stroke. Symptoms of angina include pressure, heaviness, burning, aching, numbness, squeezing or pain. These symptoms usually occur in the chest but can also be felt in the left shoulder, arms, neck, back and jaw.

Treatment for coronary artery disease includes lifestyle changes like a healthy diet, adequate exercise, quitting smoking, avoiding excessive drinking and taking medication. Common procedures like coronary artery bypass grafting can be performed to improve blood flow to the heart by grafting a healthy blood vessel taken from the leg, chest or arm to the coronary artery, which creates a new path for blood flow. Several tests are usually needed in order to properly diagnose CAD, but if you believe you may be at risk of developing it, or already have developed it, it’s important to visit a healthcare professional to discuss treatment options.

4. Fatty Liver Disease

It’s normal for everyone to have some amount of fat in the liver. Fat accumulates in the liver cells from triglycerides and other fats from the foods we eat, and if it builds up to account for more than 10 percent of the weight of the liver, it’s classified as fatty liver disease. Also known as steatosis, it occasionally causes no damage, but often it will lead to inflammation, which causes the liver to grow hardened with scarring. This condition is known as cirrhosis, and can cause serious complications if not treated.

There are two main types of fatty liver disease. The first is alcoholic liver disease (ALD), which is caused by excessive alcohol intake, hepatitis C, obesity or an overload of iron in the body. The second is non-alcoholic fatty liver disease (NAFLD), which is more likely to occur at random and to those who are middle-aged, overweight, have high cholesterol or diabetes. Other causes include medication, autoimmune disease, malnutrition or rapid weight loss. Fatty liver disease can also occur during pregnancy, though this is rare.

Often, fatty liver disease can affect a person without their knowing it. The symptoms are often non-existent or blamed on something else, as they include tiredness, weight loss, weakness, nausea and confusion. These symptoms may also be accompanied by an inflamed liver, pain in the belly, and melasma (dark-colored patches of skin) around the neck or under the arms.

Fatty liver disease can be detected through a blood test, physical examination, ultrasound, computed tomography (CT) scans, or medical resonance imaging (MRI). Treatment includes weight loss, reducing fat intake in the diet, avoiding alcohol, controlling blood sugar levels, increasing physical activity and continuing to receive regular check-ups to ensure the condition is not worsening.

5. Osteoporosis

Once we’re over the age of 35, our bones begin to gradually lose mineral density. It’s a normal part of the aging process, but for some people, it can lead to osteoporosis. Osteoporosis is a common disease that affects the bones, making them brittle and much more prone to breaks and fractures. This is due to the loss of calcium, phosphorus and other important minerals, and as the bones become thinner and weaker, even minor knocks or falls can cause serious fractures.

Osteoporosis can affect the entire body, but is most commonly experienced in the wrists, hips and spine. Known as a silent killer because it’s often not discovered until a bone is broken, osteoporosis develops gradually over the years to the point where even coughing or sneezing can cause a fractured rib. As osteoporosis is seen more in older people, broken bones can lead to problems with mobility, further fractures and other health issues.

Women are at a higher risk of developing osteoporosis as they age, due to the rapid decrease of oestrogen levels that occurs during menopause. Poor bone health can also be hereditary, and lack of calcium and vitamin D can also contribute to the risk of developing osteoporosis. Lifestyle choices like smoking, too much alcohol or lack of physical activity and medical issues like low hormone levels, thyroid problems, coeliac disease, rheumatoid arthritis and some medication can also increase the risk of osteoporosis.

If you’re at a high risk of osteoporosis, your doctor can assess you before referring you to receive a bone density scan, which measures the density of the bones and determines whether you have osteoporosis or not. Treatment includes safer variations of exercise, medication and fall prevention such as walking aids. Prevention is the best way to avoid any future issues, so ensure you follow a healthy diet and exercise regime, and visit the doctor for regular check-ups.

6. Colon Cancer

Colon (also known as colorectal) cancer occurs when uncontrolled cell growth forms in the large intestine, causing a malignant tumor on the inner walls. The majority of colon cancers begin as a polyp, which is a small growth that appears on the inner lining of the rectum or colon. Not all polyps become cancers, and generally, there are two main types: adenomatous polyps, which can change into cancer, and hyperplastic polyps, which are more common and usually not cancerous.

If colon cancer isn’t discovered and treated as soon as possible, the cancerous cells can spread and grow outward into the lymph or blood vessels, the lymph nodes and other parts of the body which damages healthy tissues and causes many health complications. Colon cancer can be a hereditary issue, and other factors including old age, poor diet, a sedentary lifestyle, obesity, diabetes, smoking and alcohol can also increase the risk of developing colon cancer.

Symptoms of colon cancer can be varied and depend on many things like the location and size of the tumor, and whether it has spread or not. They include diarrhea, constipation, stool changes, bleeding from the rectum, blood in the stool, painful bowel movements, weakness, fatigue, irritable bowel syndrome, painful cramps and gas in the abdomen and iron deficiency like anemia. These symptoms often don’t occur in the early stages of colon cancer, which is why it’s so important to have frequent bowel cancer screenings.

Treating colon cancer depends on the stage of the cancer is at. Minimally invasive surgery can be performed if the cancer is still very small and in the early stages, and if it’s become invasive, a partial colectomy, colostomy or lymph node removal might be suggested. For advanced cancers, treatment includes surgery, chemotherapy, radiation therapy and palliative care. Early detection is the best remedy, as well as leading a healthy lifestyle.

7. Nonmelanoma Skin Cancer

Nonmelanoma skin cancer refers to cancers that are not melanoma, yet occur in the skin. The two most common types are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Basal cell carcinomas begin in the top layer of skin, also called the epidermis, and can appear anywhere on the body, but are usually found on the parts that receive the most sun exposure. This type of skin cancer tends to develop gradually over time, and doesn’t spread to other parts of the body, whereas squamous cell carcinomas appear quickly and can grow rapidly over weeks or months.

Nonmelanoma skin cancers occur when the cells are damaged, by things like over-exposure to the sun’s ultraviolet (UV) rays, and tend to affect people with fair skin, freckles, light eye and hair color, or those who have had previous skin cancers. Other risk factors include the use of tanning beds, gender, age, and a weakened immune system. Symptoms of nonmelanoma skin cancers can often be confused with symptoms of other diseases, and as such they can be hard to diagnose.

Symptoms vary depending on the type of cancer. Basal cell carcinoma symptoms include open sores that bleed or ooze and refuse to heal for an extensive period of time, raised, itchy red patches, and shiny pink, red, white or translucent bumps that appear shiny. Squamous cell carcinoma symptoms include growths that look like warts, scaly red patches that bleed easily and don’t go away, open sores that have trouble healing and more.

If you believe you’re experiencing symptoms of skin cancer, it’s important to get tested immediately. Prognosis depends on the type and size of skin cancer and the age and general health of the patient, but the majority of nonmelanoma skin cancers can be successfully treated. Treatment includes biopsy, surgery, chemotherapy, or radiotherapy. Prevention of nonmelanoma skin cancer includes avoiding direct exposure to sunlight for prolonged periods of time, using a high-SPF sunscreen, wearing sun-protection clothing and properly examining your skin for any changing or new moles and sun spots.

8. Chagas

Chagas is a disease caused by a parasite known as Trypanosoma cruzi, which is transmitted to humans and animals by insect bites. It’s mainly found in America, specifically Latin America. According to the World Health Organization, over 6 million people worldwide are infected with this parasite. The infection is curable if treatment is initiated quickly, but if left untreated it can cause cardiac problems, as well as digestive and neurological issues.

Chagas disease is known as a silent killer because both phases of this disease can be free of symptoms, and life-threatening. The first phase of Chagas is the acute phase, which occurs during the first weeks and months of infection. This phase can be unnoticed because if symptoms do occur they are usually mild and can be easily dismissed. These symptoms include fatigue, headaches, rash, loss of appetite, diarrhea, nausea and vomiting. Physical symptoms can include mild swelling of the liver and spleen, swollen glands, and swelling where the bite occurred.

The next phase is the chronic phase, wherein the infection can remain dormant for decades. This is the phase in which cardiovascular and/or intestinal problems can occur, which can be potentially fatal. If you believe you’re infected with Chagas disease, it’s important to visit your healthcare professional as soon as possible. Chagas disease can be transmitted by consumption of contaminated food, so it’s important to practice proper hygiene methods.

Two avenues of treatment are available to treat Chagas. These are anti-parasitic treatment, which involves medication to kill the parasite, and symptomatic treatment, which focuses on the intestinal and cardiovascular problems that can occur during the chronic phase. There are no vaccines available currently to prevent Chagas disease, so those at risk should use bed netting, protective clothing and insect repellent to avoid infection.

9. Hepatitis

Hepatitis is inflammation of the liver, and the word ‘hepatitis’ is derived from Ancient Greek, with hepar meaning liver and itis meaning inflammation. There are different forms of hepatitis including hepatitis A, B, C, D and E. Hepatitis is usually caused by a viral infection but can be brought on by things like toxic substances such as drugs and alcohol, and the most common types are A, B and C. Types B and C are particularly dangerous, as they most commonly cause cirrhosis of the liver and certain types of cancer.

The cause of hepatitis depends on the type. Hepatitis A is caused by contaminated food or water, hepatitis B is a sexually transmitted disease, hepatitis C is spread through direct contact with the blood of a person infected with disease, hepatitis D can affect those already infected with hepatitis B, and hepatitis E is caused by contaminated drinking water. Hepatitis is either acute, which lasts under six months, or chronic, which can last much longer.

Often, hepatitis has no symptoms at all, but if they are experienced they can include flu-like symptoms, nausea, fever, dark urine, swelling, painful joints, jaundice and lethargy. Hepatitis is diagnosed by physical examination, liver biopsy, ultrasound, blood test, and testing of liver functions. Treatment will vary depending on the cause and type of hepatitis. Hepatitis A doesn’t usually require specific treatment aside from bed rest followed by vaccination, and hepatitis B usually requires no specific form of treatment but is generally treated with antiviral medication.

Hepatitis C is usually treated using a combination of antiviral medications, and if cirrhosis of the liver occurs as a result of the disease, a liver transplant may be required. Hepatitis D is treated with a specific type of medication called alpha interferon, though patients often experience hepatitis D again, even after treatment. Currently, there is no specific treatment for hepatitis E, but it generally resolves itself.

10. Cervical Cancer

Cervical cancer is a type of cancer that forms in the tissues of the cervix. It’s also known as uterine cancer, and there are two main types. Squamous cell carcinoma, which starts in the squamous cells that line the outer surface of the cervical neck, and adenocarcinoma, which develops from the glandular cells. A third, much rarer form of cervical cancer is known as neuroendocrine, which tends to be much more aggressive.

The risk factors of being diagnosed with cervical cancer stem from the human papillomavirus (HPV) infection, which is present in the majority of all cervical cancers. Other risk factors include age, smoking, weakened immune system, many sexual partners, early sexual activity and sexually transmitted diseases like gonorrhea, chlamydia and syphilis. When cervical cancer is in its early stages, it often produces no noticeable symptoms. As it advances, symptoms can include vaginal bleeding after intercourse, heavy discharge that may be bloody or watery, and pelvic pain during intercourse.

The earlier cervical cancer is detected, the more successful the outcome. Cervical cancer screenings consist mainly of Pap tests, wherein cells are brushed from the cervix and examined in a laboratory for any abnormal cells. An abnormal Pap test result doesn’t always lead to a diagnosis of cervical cancer, but abnormal cells can increase risk, and treatment is necessary. If you are diagnosed with cervical cancer, treatment depends on things such as which stage the cancer is at and any other health issues you may have.

To avoid suffering from silent diseases, it’s important to lead a life that is as healthy as possible. This includes eating a diet rich in essential vitamins and minerals, avoiding smoking and excessive alcohol, getting adequate exercise, practicing safe sex, and visiting your doctor for regular medical check-ups.