Silent but deadly diseases every doctor should watch for

By Naveed Saleh, MD, MS
Published July 7, 2021

Key Takeaways

In the best-case diagnostic scenarios, patients present with a set of signs and symptoms, a physician performs a work-up, and can then successfully diagnose and treat the condition. But what about diseases with no obvious symptoms? Diseases that disguise their warning signs and progress to an advanced stage before they are discovered?

These are known as "silent killers," and if too much time passes without treating them, they can cause serious complications or sometimes death. Let’s take a look at four such examples.

Pancreatic cancer

Pancreatic cancer is known as a silent killer for good reason. Patients with this disease are often asymptomatic until the disease has metastasized to other organs, notes the Mayo Clinic. By the time they are diagnosed, the cancer is in advanced stages and it’s too late to receive effective treatment. And early detection methods are still lacking. 

“With a 5-year survival proportion below 10%, pancreatic cancer is the deadliest solid organ cancer. If current trends continue, pancreatic cancer will become the second leading cause of cancer death by 2030,” wrote the authors of a high-powered case-control study published in PLOS One.

When symptoms do arise, they are often metabolic and gastrointestinal in nature. For instance, patients who present with newly diagnosed diabetes have four times or greater risk of a pancreatic cancer diagnosis within the next 2 years. Possible nonspecific symptoms include unintentional weight loss in those with pancreatic ductal adenocarcinoma (PDAC). PDAC can also be mistaken for pancreatitis.

In the PLOS One study, researchers attempted to determine whether the development of pancreatic adenocarcinoma could be predicted by a model of 16 risk factors and prediagnostic symptoms of pancreatic ductal adenocarcinoma, as evidenced in Medicare claims data. 

“The model provides some information bearing upon the emergent diagnosis of pancreatic cancer, but not enough on its own to be useful in population screening,” the authors concluded. “Excluding the final 3 months of claims prior to PDAC diagnosis reduced the discriminative performance of the model appreciably. Future models should consider sensitivity analyses excluding health changes noted in the final months of PDAC diagnosis in order to evaluate true clinical utility of prediction models for PDAC early detection.”

Silent heart attack

Silent ischemia may present with either no symptoms, minimal symptoms, or unrecognized symptoms. Symptoms can include feelings of indigestion, feelings of a strained muscle in the chest/upper back, or heavy fatigue. 

According to the American Heart Association, 170,000 of 805,000 heart attacks in the United States are silent. High-risk populations include women and those with diabetes. Silent heart attacks are often discovered only when a patient is receiving an EKG, echocardiogram, or cardiac MRI for another issue.

Results from a high-powered prospective study published in the Journal of the American College of Cardiology indicated that silent myocardial infarction is linked to an increased risk of heart failure, despite other risk factors for heart failure.

The authors wrote, “Currently, 5.7 million people in the United States have (heart failure) HF, and it is expected that by 2030, >8 million people will have this condition. Therefore, identifying a new potential mechanism contributing to this pandemic is of enormous importance. Although future research is needed to examine the cost-effectiveness of screening for SMI [silent myocardial infarction] as part of HF [heart failure] risk assessment, we believe that our report provides novel insights into an overlooked and potentially addressable contributor to the HF pandemic.”

Did you know that certain OTC medications may cause heart failure? Click here to learn more at MDLinx.  

Colorectal cancer

The symptoms of colon cancer—including stomach cramps and unintentional weight loss—are often subtle, and don’t usually present until advanced disease. Moreover, awareness of the risks of colorectal cancer is low, and it is rarely a beneficiary of high-profile fundraising campaigns.

Although more effective screening has led to an overall decrease in the incidence and mortality of colorectal cancer, rates are rising. According to the American Cancer Society, colorectal cancer is the third most common cancer diagnosed in both men and women in the United States (excluding skin cancers). Colorectal cancer is expected to cause about 52,980 deaths in 2021.

One effective means of preventing this silent killer is diet, according to the authors of a review published in Nutrients. Specifically, the authors pointed to the benefits of vitamin D.

“Epidemiological studies have suggested a protective role for Vitamin D in the development of colorectal cancer,” they wrote. “Both free and total 25-hydroxyvitamin D were shown to be inversely associated with colorectal cancer. A 10 ng increase in circulating Vitamin D level was associated with a 26% decreased risk of developing colorectal cancer.” 

The authors noted that definitive randomized controlled trials are needed to define risk factors that may play preventive and prognostic roles in this type of cancer. 

Learn more about other diseases Vitamin D may combat on MDLinx.


Approximately 100 million Americans have high blood pressure. Despite these high numbers, only half of these people have their blood pressure under control. People in their 30s and 40s are often diagnosed, but in light of the obesity epidemic, younger children are also being affected.

Increased blood pressure places the patient at increased risk of stroke, heart attack, and heart failure. There are often no signs and symptoms of this disease, and early detection is crucially important to institute lifestyle changes and pharmacotherapy.

Antihypertensive medications can take several days to begin working. Many patients have trouble remembering to take these drugs. The FDA recommends that “combination medicines, long-acting or once-a-day medications, may be used to decrease the burden of taking numerous medications and help ensure medications regularly.”

In a related topic, drug-induced hypertension is a serious and underappreciated problem—especially in those already taking antihypertensive drugs. Read more at MDLinx.

Share with emailShare to FacebookShare to LinkedInShare to Twitter