Top 6 Commonly Misdiagnosed Diseases

We received this article in the latest newsletter from Return2Health and thought it was really interesting so we're sharing it here:

A misdiagnosis (or wrong diagnosis) is when the doctor gives the patient the wrong or incorrect illness to treat. For example, a doctor diagnosed a patient with acute gastritis (stomach pain) when the patient had a heart attack. Or a doctor diagnosed a patient to have lung cancer when the patient is cancer-free. In the US, the rate of misdiagnosis is estimated to be between 10-15%.

According to a study published in the Medical Journal of Australia last September 2020, doctors determined that the number of diagnostic errors, including misdiagnosis, was estimated to be around 140,000 annually in Australia. Of these cases, 21,000 have resulted in serious harm to the patient and between 2,000 to 4,000 deaths. It’s unfortunate and sad to know that more than 80% of diagnostic errors can be prevented.


1. A stroke or cerebrovascular accident (CVA) happens when the blood supply to a part of the brain is reduced or interrupted, blocking brain tissue from acquiring nutrients and oxygen. It’s a medical emergency involving the death of brain cells in minutes, so prompt treatment is crucial.

Why is it commonly misdiagnosed? Stroke is frequently misdiagnosed when the patient does not present with the typical signs and symptoms of stroke like facial drooping, arm weakness, speech difficulties, and the acute presentation of symptoms. Instead, the patient presents with dizziness, altered mental status, and nausea or vomiting. Which condition/s is it usually confused with? Stroke is usually confused with epilepsy, multiple sclerosis, brain lesions (like tumours, abscess, meningitis) and a person having a hypoglycaemic episode (low blood sugar). What is the most accurate diagnostic test (gold standard test) to confirm a diagnosis of stroke? During the first three hours of suspecting a stroke, non-contrast head CT scan (computerised tomography) is the gold standard for diagnosing stroke.

2. Sepsis is a life-threatening medical emergency wherein a localised infection you already have triggers a serious chain reaction throughout your body. It’s your body’s extreme response to an ongoing infection.

Why is it commonly misdiagnosed? Sepsis typically happens in the setting of a critically ill patient (admitted to the intensive care unit). Thus, its diagnosis can be challenging and blurred by the presence of inflammation and other diseases that are making the patient sick. Sepsis doesn’t happen alone, which makes its diagnosis hidden and more difficult. Therefore the doctor should always keep this diagnosis in the back of their mind whenever the patient's condition becomes critical. Other doctors also add that sepsis is misdiagnosed because the symptoms are misinterpreted and not thoroughly assessed. Which condition/s is it usually confused with? Other conditions that meet the criteria for sepsis that may be confused with it include pulmonary embolism, anaphylaxis, adrenal insufficiency, and diabetic ketoacidosis. What is the gold standard test to confirm a diagnosis of sepsis? A blood culture analysis remains the gold standard test for diagnosing sepsis.

3. Lung cancer is a type of cancer wherein cells in the lungs grow out of control and invade neighbouring tissues and organs. It can also develop secondary growths in distant organs (metastasis) like the other lung, liver, adrenal glands, bones, and brain.

Why is it commonly misdiagnosed? When a doctor tells you that you have lung cancer, it’s definitely life-changing. According to statistics, it has killed more New Zealanders than any other cancer combined. It’s also the number one cancer causing death among Australians. Many early symptoms of lung cancer like coughing up blood and shortness of breath are non-specific, meaning they can be seen in other diseases. A misdiagnosis of early signs and symptoms can tremendously impact a patient’s treatment outcome and quality of life. Which condition/s is it usually confused with? Conditions that are typically confused with lung cancer are pneumonia, asthma, chronic obstructive pulmonary disease, acid reflux, and gastroesophageal reflux disease (GERD). What is the gold standard test to screen and confirm a diagnosis of lung cancer? The gold standard test for screening lung cancer is low dose computed tomography (LDCT) scan. If a large nodule is seen that looks like cancer, a biopsy may be done next to confirm the diagnosis. Additional imaging tests like positron emission tomography (PET) scan are also requested. The goal of lung cancer screening (or any other cancer screening) is early detection during its initial stages when the chances of curing it are still high. When signs and symptoms have already manifested, lung cancer is more often than not in the advanced stages.

4. Heart attack. A heart attack is a medical emergency in which blood supply to a part of the heart is suddenly blocked, typically by a blood clot.

Why is it commonly misdiagnosed? Ischaemic heart disease (also called coronary heart disease) is one of the leading causes of death in New Zealand and Australia (2019). Almost all of those deaths are attributed to a heart attack; a complication of ischaemic heart disease. A heart attack, medically referred to as an acute myocardial infarction, needs prompt diagnosis and correct treatment to reduce the risk of death or disability. A heart attack may be misdiagnosed because of one of the following reasons:

  • When the chest pain presents as a burning epigastric pain (pain on the stomach area). The pain is typically dismissed as secondary to dyspepsia or heartburn.

  • A silent heart attack? Yes. Some people experience a heart attack without having any perceivable symptoms. It’s usually seen among women or people diagnosed with diabetes.

  • Watch out for this one. Women are more likely than men to complain of pain not located on the chest, which the doctor could miss or ignore. A 2018 research article published in the Circulation Journal stated that women presented with more additional symptoms than men, which could mislead the doctor to other diseases. Other signs and symptoms include the following: pain in both arms (instead of just the left arm), shoulder or upper back pain, difficulty breathing, sleep problems, anxiety, and fatigue that is gradual or acute in onset.

Which condition/s is it usually confused with? Conditions that commonly mimic a heart attack include pulmonary embolism, gastroesophageal reflux disease (GERD), stable angina, anxiety attack, and musculoskeletal pain. What is the gold standard test to confirm a diagnosis of a heart attack? The best way to diagnose a heart attack is to use the World Health Organisation’s definition. It requires any two of three criteria: ischemic symptoms led by the characteristic chest pain, electrocardiographic (ECG) changes, and elevated cardiac enzyme levels in the blood (either high creatine kinase-MB levels or elevated troponin levels). If you have any two of the three criteria, you’re having a heart attack. Note: If you’re having any form of chest pain, act quickly. Take yourself or ask someone to take you to the nearest hospital.

5. Breast cancer is a type of cancer wherein cells in the breast grow out of control.

Why is it commonly misdiagnosed? Breast cancer is the third most common cancer in New Zealand. It accounts for greater than 600 deaths per year. It was estimated to be the most common cancer diagnosed in Australia for 2019. Breast cancer diagnosis errors can be as high as 70% of cases among doctors who lack breast cancer specialisation. These errors include delayed diagnosis, failure to diagnose, and misdiagnosis. Misdiagnosis of breast cancer usually depends on various symptoms that breast cancer patients manifest. A breast lump or mass is the most common symptom of breast cancer. After identifying this breast mass, the following actions are pretty straightforward and cause fewer misdiagnosis cases than those who present with additional symptoms. The most common source of misdiagnosis for breast cancer is a combination of three factors: the presence of a palpable breast mass, a negative mammogram result, and no further action on the doctor's part after the first two factors. To minimise the occurrence of this usual source of misdiagnosis, the patient should be offered to undergo a biopsy. Early detection is the key to successful treatment of breast cancer. It’s advised that women obtain breast cancer screening on a yearly schedule to detect early breast changes. Self-examination is also encouraged regularly. Which condition/s is it usually confused with? Breast cancer presenting as a lump on the breast can be confused with other diseases of the breast like fibroadenomas or cysts (benign) and metastasis of other types of cancers (colon, lung, or liver) to the breast. What is the gold standard test to confirm a diagnosis of breast cancer? A biopsy of the breast mass is the gold standard to confirm a diagnosis of breast cancer. The gold standard for screening breast cancer is mammography.

6. Deep Vein Thrombosis (DVT). DVT is a blood clot inside a deep vein, usually located in the leg.

Why is it commonly misdiagnosed? DVT symptoms include pain in the leg, swelling in the affected leg, discolouration of the skin of your leg, and a warm feeling over the affected leg. It can also occur without perceivable symptoms. The symptoms are nonspecific and commonly experienced. Which condition/s is it usually confused with? A DVT can be misdiagnosed as sciatica, cramp (it happens), varicose veins, peripheral artery disease, and muscle strain. What is the gold standard test to confirm a diagnosis of deep vein thrombosis? Contrast venography was the traditional gold standard for DVT diagnosis. Because of its high cost and invasiveness, some medical centres have replaced it with duplex ultrasonography as the gold standard. Note: Consult with your doctor if you experience symptoms of DVT. It’s a lot better to be wrong about your suspicion or diagnosis than to be right about it. One of the dreaded complications of DVT is a pulmonary embolism; a medical emergency.

There are thousands of diseases or disorders that have been discovered over the past 100 years. The process of diagnosing a patient with the right condition is definitely a lot more challenging and complex than it used to be. There are several or even hundreds of diseases that can fit in the diagnosis for every symptom that you have. Misdiagnosis happens but can be avoided or lessened. As a patient, be honest with your medical history, ask questions, and get a second opinion if you feel you need to.