Hypoglycemia is the clinical term given to a reduction of glucose concentration in the blood. These levels are always changing depending on various factors: the nutrients we take from our food, the secretion of insulin by the pancreas, and the creation of glucose by the liver. These internal mechanisms are designed to achieve something called glucose homeostasis, that is, the correct balance of glucose levels in the blood. However, when one of these systems and measures fail for one reason, and it is not compensated by the other, hypoglycemia ensues. It is typically an acute problem causing an array of signs and symptoms that could be very mild or quite severe, depending on the concentration of glucose and the susceptibility of the patient.
Hypoglycemia is usually a transient problem that is quickly solved with home measures. However, it may become a major problem in diabetics, older patients, neonates, and pregnant women. In any case, it is important to know and understand the signs and symptoms of this medical condition in order to contribute with early detection and quick implementation of first aid measures to improve the symptoms.
» Now, we will discuss the symptoms of low blood sugar “hypoglycemia”.
1. Sweating
This is a typical symptom of hypoglycemia, and it is caused by an activation of the adrenergic pathways in the central nervous system. It is called a sympathoadrenal symptom because it triggers the sympathetic nervous system, a branch of the autonomic nervous system that is in charge of the response of the body to stressful stimuli. Thus, a patient with hypoglycemia would typically have various symptoms we will describe further, and profuse sweating is a common feature to distinguish this entity from many others.
There are many other causes of profuse sweating, especially night sweats and hot flashes caused by hormonal imbalances in postmenopausal women. However, hypoglycemia-related sweating has an acute onset and progresses rapidly along with muscle weakness and dizziness as we will further describe.
2. Muscular weakness
Glucose is essential for muscle function, and it is required instantly to promote movement. The more strength you use, the more glucose your muscles need to start and maintain the movement. Therefore, hypoglycemia directly affects muscle function. Additionally, it will affect your nervous system because it requires energy in the form of glucose to operate correctly. Thus, muscular weakness falls into the neuroglycopenic symptoms, which is the same to say “symptoms of low levels of glucose in the nervous system.”
3. Dizziness and fainting
Feeling dizzy is a very uncomfortable symptom that is listed as a neuroglycopenic sign as well. It is caused by a sudden and unexpected shortage of energy in the brain. Even if we have other means to power-up the brain, they do not work as fast as glucose. Thus, during acute hypoglycemia, we may feel lightheaded and dizzy, sometimes even faint.
Fainting is more common in older adults and pregnant women, but it is not only limited to these patients. There are patients more susceptible than others, and slight changes in their glucose levels may cause fainting. In other cases, there are patients who would display a lower level of glucose and still do not experience so many signs and symptoms.
Fainting is a clearly severe symptom, and in most cases, it should be taken seriously and readily attended by a healthcare professional. Thus, do not delay searching for medical attention and applying first aid measures; meanwhile, if apparent hypoglycemia makes a patient faint.
4. Blurred vision
Another system that is deeply related to the nervous system and becomes affected right away during hypoglycemia is our visual perception. Our vision requires many different functions at the same time in order to keep ongoing. One of them is glucose; another is good irrigation of blood. In most cases, hypoglycemia is paired up with hypotension, as we will see further. That’s why we get a blurred vision: The eyes become unable to process and translate light impulses into nervous impulses because it starts lacking nutrients and oxygen that is being delivered to sensitive organs such as the brain and the hearth.
5. Difficulty to concentrate
As much as we disregard thinking and cognitive functions, they take quite a lot of neuronal processing, and they consume a lot of energy. In hypoglycemia, nutrients are being delivered to the most important centers in the brain, as well as other organs that keep us alive, such as the heart. Thus, other functions become relegated to a secondary priority, and that is why we become unable to concentrate and might even find trouble trying to recall certain events or create new memories. This has nothing to do with intellect. It is the result of a low level of energy available in the brain.
For this reason, some people undertaking very low-carbohydrate diets would start feeling difficulty to keep on learning and concentrating. This is often corrected after some time, but it is a very slow process because there’s nothing like glucose to get a faster energy supply.
6. Anxiety
Patients with hypoglycemia usually come to the emergency room with a very high level of anxiety, especially if they are experiencing neurological symptoms. After fainting or feeling dizzy with muscular weakness and other concerning symptoms in hypoglycemia, patients usually think they have a severe problem that needs urgent correction, and this makes them and their relatives very nervous. Additionally, as we mentioned earlier, the sympathetic nervous system activates in hypoglycemia, and it contributes to making patients feel even more nervous and fidgeting.
Thus, in the event of hypoglycemia, it is important to look for urgent medical attention, but stay calmed and apply first aid measures until medical help arrives. Some first aid measures would be to give space to the patient, ventilate, and give him something to drink, usually a sweet drink if the patient is not diabetic. I diabetic patients it is sometimes better to test their glucose levels before applying any measure unless there’s a clear history that suggests hypoglycemia such as insulin overdose or low energy intake.
7. Hypotension
Hypoglycemia and hypotension usually come together as one, and it is actually a complication of having low levels of glucose in the blood. Hypotension is a low blood pressure, which is a measure of how fast the blood circulates the cardiovascular system. A low blood pressure leads to a reduction of blood flow in the smaller arteries because as it goes down the blood flow in these minute blood vessels become slower. Hypotension further aggravates the energy failure in the central nervous system and the musculoskeletal system and makes the symptoms of hypoglycemia even more severe. Thus, if you’re suspecting hypoglycemia in a patient with severe symptoms, there’s a high chance he’s also experiencing hypotension and needs to be tested and attended by a doctor.
8. Tachycardia
The organism has its way to counter the deleterious effects of certain health problems, such as low blood pressure and low levels of glucose in the blood. Trying to compensate hypoglycemia, the heart needs to create extra glucose, which does not happen fast enough. However, there’s a way to compensate hypotension, and it is by increasing your heart rate. That is why, in most cases, you will see these individuals with very low blood pressure and accelerated heart rate. If you can’t measure a patient’s blood pressure, you can still test how fast is his heart beating, and that would give you an estimate of whether or not his blood pressure might be low.
However, you must keep in mind that many different things may be increasing blood pressure, including anxiety. Also, in some types of patient, blood pressure might be quite low, and their heart does not react by increasing heart rate, or it may do so in a small degree. Thus, the ultimate way to know his blood pressure readings is through a consistent measure made by a doctor.
9. Rapid breathing (Tachypnea)
Similar to rapid heartbeats, rapid breathing may be caused by hypoglycemia, anxiety, or both. These patients often breathe very rapidly, taking small breaths instead of longer breaths, and become easily agitated. When this is sustained for a very long time, rapid breathing can lead to an imbalance in blood gas and blood pH. In other words, this patient may require urgent medical attention. Thus, do not delay looking for the assistance of a doctor, especially if the patient is a senior, a pregnant woman, an infant, or a patient with a debilitating health condition.
10. Bradycardia in neonates
We mentioned that certain individuals would display a slower heart rate instead of increasing this vital sign. That’s the case of neonates with hypoglycemia. These patients have a very rapid heartbeat compared to adults, and the normal range changes as the baby get older. Bradycardia in infants may feel similar to our own heartbeat because their normal ranges are higher and should remain so. If you suspect hypoglycemia in your neonate or infant or find what your think is an abnormality in his heart beating, go straight to your doctor and try not to delay diagnosing your child. Besides hypoglycemia, there are many alterations in the structure of the heart that may be causing these and other symptoms.
11. Hypothermia
Patients with hypoglycemia start having circulatory changes as we have reviewed above. Blood pressure often drops along with glucose levels, this changes their heart rate as well, and the blood starts redirecting to meet the oxygen and nutrient demands of very important organs such as the heart and the brain. As the circulatory system redirects the blood to the inner parts of the body, the outer parts, including the skin and the mucosal layers reduce their blood flow and start feeling colder. That is why the patient may feel colder than usual, and this can be confirmed by taking his temperature.
There are many other causes of hypothermia, and it may be an additional source of health problems in cold weather. Thus, it is important to look for medical attention if you are not able to improve the symptoms by applying first aids measures.
12. Hunger
Patients with hypoglycemia usually start feeling hungry even before hypoglycemia symptoms start showing up. The majority of cases are preceded by a prolonged fasting time, usually longer than 6-8 hours. And even when this is not the case, patients may start feeling hungry as a defense mechanism, the body has to increase the circulating levels of glucose. As the brain perceives hypoglycemia, it starts sending a series of stimuli to promote the sensation of hunger and force the individual to take food in order to replenish the normal levels of energy and improve the symptoms.
13. Nausea, vomiting, and abdominal cramps
People with hypoglycemia may also have several gastrointestinal symptoms, including abdominal pain or discomfort, but more usually nausea and vomiting. Since they are often in a fasted state, vomiting might contain a yellow or greenish liquid that is called bile. Note that bilious vomiting might be related to various diseases, and it is an alarm sign in neonates.
14. Confusion and severe neurological symptoms
In severe cases of hypoglycemia or in susceptible populations, patients may start displaying severe neurological symptoms that may range from confusion and seizures to lethargy and coma. A very low level of energy to the brain and very low blood pressure might influence severe damage with a long-lasting lesion to various brain structures when not readily attended.
Hypoglycemia is a very common problem that may have severe consequences in susceptible patients. Neonates, older adults, pregnant women and people with diabetes mellitus deserve a special mention as they usually need urgent attention and in some cases may also need to be hospitalized. Many different first aid measures might work to treat these patients, but it is recommended to contact a healthcare professional for a full assessment of the health conditions in order to reach a proper understanding of the disease and detect any additional health problem we may need to address.
References
Mathew, P., & Thoppil, D. (2018). Hypoglycemia. In StatPearls [Internet]. StatPearls Publishing.
Egi, M., Bellomo, R., Stachowski, E., French, C. J., Hart, G. K., Taori, G., … & Bailey, M. (2010, March). Hypoglycemia and outcome in critically ill patients. In Mayo Clinic Proceedings (Vol. 85, No. 3, pp. 217-224). Elsevier.
Bromiker, R., Perry, A., Kasirer, Y., Einav, S., Klinger, G., & Levy-Khademi, F. (2019). Early neonatal hypoglycemia: incidence of and risk factors. A cohort study using universal point of care screening. The Journal of Maternal-Fetal & Neonatal Medicine, 32(5), 786-792.