Hyperglycemia: Symptoms to Pay Attention To

Having high blood sugar (glucose), also known as hyperglycemia, most often appears in people with diabetes but can also occur with the use of certain medications, such as steroids, or in certain conditions, including pancreatic disease and Cushing syndrome. Sometimes, being sick with something as simple as the common cold can cause blood glucose levels to escalate in those with diabetes. Emotional stress, such as grief or a lousy work situation, can also send your blood sugar soaring. 

The hormone insulin is typically released from your pancreas when you eat carbohydrates. Insulin lowers blood sugar by unlocking the cells so that they can pick up the glucose from the blood. Some people either don’t make enough insulin, or the cells are resistant to the insulin produced. 

Any glucose that isn’t immediately needed for energy is stored in the muscle and liver for future use. If you have diabetes, making proper diet choices, exercising regularly, and taking your medication as prescribed will help to prevent high blood sugar. 

Even moderately elevated blood sugar can adversely affect our health. Some examples of long-term complications of hyperglycemia include kidney damage, cataracts, and skin infections or ulcerations. This is why the U.S. Preventive Services Task Force recommends blood glucose testing for all adults who are overweight or obese between the ages of 40 and 70. 

Frequent Urination

Healthline succinctly explains why people with high glucose might have frequent urination. Medical professionals refer to this as “polyuria.” You might not only urinate more often but be surprised by how much you urinate at one time. According to diabetes.co.uk, the average person passes one to two liters per day, while someone with polyuria passes at least three liters.   

Excess sugar in your blood causes the kidneys to work harder to excrete it. If you begin to wake up in the middle of the night to pee, and you never have before, this could be a sign that you need a diabetes screening. In the early stages of diabetes, it is not uncommon for individuals to become dehydrated due to increased urine output. Frequent urination can be a sign of type 1 or type 2 diabetes. Still, frequent urination is only one sign of diabetes and shouldn’t cause much worry unless accompanied by other symptoms. 

Increased Thirst

As polyuria refers to frequent urination, polydipsia refers to frequent thirst, and as you can imagine, the two are usually a package deal for people with high blood sugar. Because you are urinating more to rid the body of that extra blood sugar, you’ll likely feel thirstier as the body tries to compensate for the fluid loss. The body will also extract stored fluid from your tissues in an effort to meet its needs, leading to dehydration for many people. 

As WebMD reminds readers, many medications, including steroids and antipsychotics, can also cause dry mouth, as can various medical conditions. People with diabetes should be aware of the symptoms of dehydration, which include nausea, dizziness, and headaches. If you become severely dehydrated, your kidneys won’t be able to excrete the glucose in your blood since you’re peeing less, and your blood sugar will increase. If you have diabetes, you must drink plenty of water every day to prevent dehydration and keep the kidneys functioning in tip-top shape. 

Blurred Vision

Blurry vision is not a cause for panic if you have diabetes. Even adjusting to a new insulin dosage can cause transient vision changes  (via Optometrists Network). Still, it should be a wake-up call if you haven’t seen an optometrist recently or aren’t following the diet, physical activity, and medication guidelines for glycemic control. If you haven’t been diagnosed with diabetes but suddenly experience trouble seeing clearly, you should ask your physician about being screened for diabetes.

High blood sugar causes the fluid in your eyes to shift, which results in swelling o the eye’s lens. If this is the cause of your blurry vision, getting your blood sugar under control will stop the problem. Over an extended period, chronically elevated blood sugar levels can cause a vision-threatening condition, diabetic retinopathy, resulting from damaged blood vessels. Sadly, about half of the people diagnosed with diabetic retinopathy will also have diabetic macular edema, which causes permanent vision loss. 

The American Diabetes Association advises everyone with type 1 diabetes to get an eye exam within five years of their diagnosis. Those with type 2 diabetes should have an eye exam as soon after diagnosis as possible, as should women with diabetes who are pregnant or are planning to get pregnant. 


In one study published in Diabetes Care, among those newly diagnosed with type 2 diabetes, 61% complained of fatigue, which did not necessarily improve once normal blood glucose was achieved. An acute episode of either hyperglycemia or hypoglycemia will result in easily-corrected fatigue, while a chronic pattern of glucose fluctuations will contribute to chronic fatigue. 

Although illness can trigger fatigue in diabetes and other chronic health conditions, behaviors and thought processes can perpetuate it. For example, feeling that fatigue is out of your control and focusing on how tired you are can exacerbate it. Additionally, the more tired you are, the less likely that you’ll feel motivated to exercise, but lack of physical activity can also trigger and worsen fatigue.

 In this study, 350 participants with type 1 diabetes between 18 and 75 years of age were asked to complete questionnaires and were matched with a control group with similar demographic backgrounds. Participants were asked questions to assess their fatigue severity over the previous two weeks. Sixty participants had their blood glucose levels continuously measured for five days. These participants were asked to rank their level of fatigue at six points throughout the day. A significantly higher percentage of patients with type 1 diabetes had chronic fatigue symptoms than matched controls, and their fatigue severity was considerably higher. Those with depressive symptoms were even more likely to experients fatigue, as were those with neuropathy, nephropathy, and heart disease. 

Among the 34 assessed diabetes-related symptoms, fatigue was the most troublesome. The five most problematic symptoms were “overall sense of fatigue, lack of energy, increasing fatigue in the day, fatigue in the morning when getting up, and sleepiness or drowsiness. Chronically fatigued patients were more likely to experience hypoglycemia (low blood sugar) throughout the day. 


People newly diagnosed with diabetes often complain of headaches when they are establishing a treatment regimen. Although you might not think of it, exercising can help to stop a headache caused by hyperglycemia. Drinking water might also help rectify the dehydration that is often the underlying cause of these headaches (via Diabetes Self-Management). However, people with type 1 diabetes and ketones in their urine should not engage in physical activity. 

According to Verywell, the hormone fluctuations caused by hyperglycemia might lead to headaches. Other causes of headaches among people with diabetes are infection, stress, high blood pressure, and dehydration. Still, if your headache is severe, you can’t get your blood glucose back down, or you’re experiencing other symptoms along with the headache, it’s essential to seek medical care.

Fruity-Smelling Breath

Per WebMD, a fruity breath scent similar to that of acetone (think of the smell of nail polish remover) occurs in ketoacidosis, a condition resulting from the buildup of acids in the blood when the body is unable to use glucose for energy and must rely on fat instead. 

Ketoacidosis is most likely to develop in type 1 diabetes but can also occur in type 2 diabetes. Other symptoms of ketoacidosis include nausea, vomiting, shortness of breath, dry mouth, weakness, confusion, and abdominal pain. Ketoacidosis can lead to a coma if it goes on long enough without medical intervention (via the Mayo Clinic). 

People with diabetes should always have ketone test strips on hand to check their urine for the presence of ketones. If your blood sugar is staying above 300 mg/dL or you have more than one symptom of diabetic ketoacidosis, seek medical treatment immediately. 

Nausea and Vomiting

There are several explanations for why people with hyperglycemia might experience nausea. Elevated blood sugar levels themselves can cause nausea (via Healthline). The most commonly prescribed diabetes medication, Metformin (Glucophage), causes nausea, especially when taken on an empty stomach. Injectable medications for diabetes, including exenatide (Byetta), liraglutide (Victoza), and pramlintide (Symlin), also cause nausea, especially when you first start to use them. 

Nausea is another symptom of ketoacidosis that results from very high blood glucose levels. People with prolonged hyperglycemia are also at risk of developing gastroparesis or delayed stomach emptying caused by nerve damage in the stomach. Symptoms of gastroparesis include nausea, vomiting, heartburn, abdominal pain and swelling, frequent swings in blood sugar, loss of appetite, and nutrient deficiencies (via Mayo Clinic). Diabetes also increases the chances of pancreatitis development, which causes symptoms including nausea, vomiting, abdominal pain, and elevated triglycerides in the blood. 


According to Diabetes.co.uk, when diabetes is uncontrolled, and the cells are resistant to insulin, or the pancreas cannot produce a sufficient amount of insulin, hunger can result as the body tries to overcome the lack of energy brought about by the body’s inability to use glucose as fuel.  However, eating will not get rid of hunger and will only further increase blood glucose. This excessive hunger is called polyphagia. Despite the increase in food intake, individuals with undiagnosed or uncontrolled diabetes will often still lose weight because the body must rely on muscle and fat to meet its energy needs (via endocrineweb). 

Just looking at or smelling food can cause your pancreas to release insulin (via The Diabetes Council). In turn, elevated insulin levels can increase hunger and make food taste better (especially sweets). People with hyperglycemia should focus on high-fiber foods to satisfy their hunger and drink plenty of water. 

Mood Changes

A study published in Diabetes Care found that among 20 participants with type 2 diabetes and a median age of 61.5, mood state deteriorated during periods of hyperglycemia. The participants described feeling low-energy, sad, and anxious when their blood sugar was elevated. 

Research appearing in Scientific Reports in 2017 determined that the consumption of sugary food increases the chances of developing depressive symptoms. Men in the highest tertile of sugar intake had a 23% increased odds of developing this common mental disorder within five years. This association was independent of health behaviors, socio-demographic factors, other dietary variables, body fat, and the presence of other health conditions. 

After reviewing mood and glycemic control research, Isa Kay, MPH, RDN, wrote for the University of Michigan that practicing stress-management techniques will improve blood glucose control. She recommends that people struggling with mood changes and hyperglycemia focus on eating foods rich in protein and fiber while simultaneously decreasing their intake of added sugar and refined carbohydrates. 

Dental Problems

If you’re suddenly developing cavities and other dental problems, it might be time to get your blood glucose checked. Sugar nourishes the bacteria in the mouth, increasing the amount of plaque on the teeth. Plaque is acidic and attacks the teeth surfaces, leading to dental caries and gum disease (via the Mayo Clinic). This plaque hardens, especially if you aren’t diligent with brushing and flossing, into tartar beneath the gum line, where you can’t get to it. The plaque and tartar are irritating to the gums and cause the gums to become inflamed and susceptible to bleeding. 

The condition of having fragile gums due to plaque and tartar is known as gingivitis. Gingivitis might progress to periodontitis, resulting in the destruction of soft tissue and bone in the mouth. Eventually, tooth loss occurs if you don’t get treated and change your lifestyle and dental hygiene habits. People with diabetes are more susceptible to infection and poor healing, increasing the chances that periodontitis will rear its ugly head. 

Excess sugar in the mouth also feeds yeast and can increase the chances that you’ll develop a painful yeast infection in your mouth, known as oral thrush. The dry mouth that occurs in poorly controlled diabetes also increases the chances of developing these dental problems. 

Cognitive Problems

In a study published in Diabetes Care, 20 participants with type 2 diabetes and a median age of 61.5 experienced decreases in information processing speed, working memory, and attention during episodes of hyperglycemia. Accuracy wasn’t lessened in this research, but speed was sacrificed when blood sugar was elevated. Previous studies have shown poor language skills and reduced IQ associated with hyperglycemia. 

Ongoing research has found that people with type 2 diabetes are more likely to develop cognitive impairment, most likely due to the metabolic derangements that occur with diabetes. It appears that hyperglycemia might negatively affect cerebral function. Acute hyperglycemia has also been found to worsen the cerebral damage caused by ischemic stroke. 

Abdominal Pain

It is not uncommon for people with diabetes to complain of abdominal pain, which can occur due to complications involving the gastrointestinal tract, liver, pancreas, or biliary disease. According to a study published in Endocrinology Advisor, up to three-quarters of patients with longstanding diabetes have gastrointestinal complaints. 

For example, gastroparesis that results from nerve damage in the stomach causes delayed emptying of the stomach, leading to stomach pain.  According to the authors of this study, 40% of people with type 1 diabetes and 10-20% of those with type 2 diabetes will develop gastroparesis. Alternatively, the pain might be a result of impairment of the gallbladder. Patients with diabetes are two to three times more likely to develop gallstones than individuals who do not have diabetes.  Fatty liver disease also occurs more often among people with insulin resistance and diabetes. The pain from fatty liver disease is usually isolated in the right upper quadrant. 

People with diabetes might develop small bacterial overgrowth (SIBO) if hyperglycemia has injured the nervous system in the intestines. SIBO causes abdominal discomfort secondary to the production of gases by the bacteria that colonize the gut. Two-thirds of people with diabetes experience this uncomfortable condition, resulting in abdominal bloating and pain. People with diabetes are also more likely to develop constipation, which can also be painful. 

Slow-healing Cuts and Sores

High blood sugar levels will stop nutrients and oxygen from providing energy to cells, damage the immune system, and increase inflammation throughout the body (via Healthline). As a result, wounds are slow to heal and more likely to worsen when blood sugar levels are high. A simple scratch on the foot can rapidly progress to a deep ulcer needing immediate medical attention. It’s been estimated that about one in five people with diabetes who develop an ulcer will necessitate lower limb amputation. 

Peripheral neuropathy might develop if blood sugar levels remain elevated for an extended period. In this condition, the nerves and vessels become damaged, lessening sensation in the hands and feet. Because people with neuropathy don’t have adequate feeling, they might not know that they have wounds or how severe those wounds are until it’s too late. 

Not to be confused with peripheral neuropathy, peripheral vascular disease is another leading cause of skin problems among individuals with diabetes. In fact, people with diabetes are twice as likely to develop this condition in which the blood vessels are narrowed, lessening the ability to blood to reach the limbs. Glucose also increases blood viscosity, making it even less likely to adequately reach the limbs.