hypoglycemic coma



OVERVIEW

Definition

Hypoglycemic coma is a neurologic syndrome with a series of cognitive deficits and impaired consciousness caused by severe hypoglycemia.

In the general population, blood glucose levels below ≤2.8 mmol/L are characterized as hypoglycemia. In diabetic patients, blood glucose ≤3.9 mmol/L is recognized as hypoglycemia. Hypoglycemia can lead to a series of nervous system dysfunction, and in severe cases, coma can occur.

Hypoglycemic coma can occur in non-diabetic people or in diabetic patients. Prompt treatment of hypoglycemic coma can quickly restore blood glucose levels and make hypoglycemic symptoms disappear. However, severe hypoglycemia or prolonged coma can cause a series of irreversible neurological sequelae, and may even be life-threatening.

Classification

There are many ways to classify hypoglycemia, and the common classifications are as follows:

American Diabetes Association Classification

Severe: requires third-party intervention for treatment due to cognitive impairment. This entry discusses this type of hypoglycemia.

Documented Symptoms: symptoms are not severe, symptom development is confirmed by blood glucose measurements, and self-treatment can lead to improvement.

Asymptomatic: detected only by testing blood glucose values.

Possibly symptomatic: symptoms of hypoglycemia develop without blood glucose measurement.

Pseudohypoglycemia: blood glucose is not low (>3.9 mmol/L), but hypoglycemic symptoms develop [1,2].

Classification of the Chinese Medical Association Diabetes Branch

Severe hypoglycemia: requires assistance from bystanders, often with impaired consciousness.

Symptomatic hypoglycemia: blood glucose ≤3.9 mmol/L with hypoglycemic symptoms.

Asymptomatic hypoglycemia: blood glucose ≤3.9mmol/L, but without hypoglycemic symptoms [3].

Classification according to the etiology of hypoglycemia

Hypoglycemia occurs less frequently in healthy conditions and almost exclusively after extreme exercise or in severe starvation. Patients with severe medical conditions such as combined severe hepatic and renal insufficiency, malignant tumors, etc., may experience coma symptoms [4-5].

Severe hypoglycemic symptoms often occur in diabetic patients due to improper diet and exercise and adjustment of glucose-lowering regimen [6].

Etiology

Causes of the disease

Hypoglycemic coma occurs as a result of low glucose concentration in the blood, <2.8 mmol/L in nondiabetic patients and ≤3.9 mmol/L in diabetic patients.Causes of hypoglycemia include the following:

Disease factors

Islet cell tumors, glucagon deficiency.

Inadequate secretion of anti-insulin hormones, such as anterior pituitary hypopituitarism, hypoadrenocorticism, and hypothyroidism decreases secretion of growth hormone, adrenocorticotropic hormone, and thyroxine.

In patients with severe liver disease, the liver cannot regulate blood glucose effectively due to insufficient glycogen storage in hepatocytes and low glycogen isomerization.

Malabsorption exists after intestinal surgery, such as gastrectomy.

Drug factors

It is mainly seen in diabetic patients using oral hypoglycemic drugs or inappropriate use of insulin.

Some other drugs may also cause hypoglycemia, such as quinolone antibiotics (levofloxacin) and beta-blockers (metoprolol), which have been reported to cause hypoglycemia after overdose.

Other factors

Insufficient sugar intake such as excessive dieting and starvation.

Excessive blood sugar consumption such as strenuous exercise, fever, severe diarrhea, etc.

Autonomic dysfunction such as idiopathic functional hypoglycemia.

Alcohol consumption.

Predisposing factors

Insulin adjustment in diabetic patients.

Failure to eat on time or eating less.

Increased exercise.

Alcohol consumption.

Presence of severe hepatic and renal abnormalities.

Pathogenesis

Hypoglycemic coma is due to low blood glucose levels, and the mechanisms of hypoglycemia include the following pathways [7-8]:

Inadequate sugar intake: Decreased blood glucose levels occur due to unmet somatic demand for sugar as a result of eating too little sugary food or impaired intestinal absorption.

Increased sugar consumption: In situations such as strenuous exercise or fever, blood glucose consumption is significantly increased compared to normal levels, and if it is not replenished in a timely manner, a decrease in blood glucose levels will ensue. Improper use of hypoglycemic drugs by diabetic patients may also cause excessive blood sugar consumption.

Abnormal blood glucose regulation: Under normal circumstances, the body will convert the remaining glucose into glycogen to be stored in the liver, muscles and other parts of the body, when the body consumption increases, glycogen will be converted into glucose to be released into the blood. If there are abnormalities in glycogen synthesis and decomposition, blood sugar is not effectively regulated and hypoglycemia may occur.

Symptoms

Main Symptoms

Hypoglycemic coma is mainly characterized by loss of consciousness and inability to be awakened, but coma is often preceded by the typical manifestations of hypoglycemia, which will develop into coma if not treated in time. Common manifestations include:

Sympathetic arousal

Common palpitations, cold sweats, anxiety, marked hunger, and pallor [9].

Central nervous system symptoms

Altered consciousness such as drowsiness and lethargy.

Impaired cognitive function.

Amnesia.

Weakness in limb movement, slurred speech.

Epileptiform seizures etc.

Other symptoms

Cardiac arrhythmia.

Agitation.

Hallucinations.

Severe hypoglycemia can induce angina pectoris and myocardial infarction, which can present with chest pain, chest tightness, and back pain [10].

Complications

Brain damage.

A severe and prolonged drop in blood glucose can cause altered mental status, cognitive impairment, convulsions, or coma due to lack of sugar in brain tissue.

Severe hypoglycemia lasting more than 6 hours can lead to permanent brain damage.

Myocardial ischemic disease

Hypoglycemia in the elderly is prone to induce angina pectoris and myocardial infarction.

Cerebral ischemia/infarction

Hypoglycemic episodes in the elderly can lead to transient cerebral ischemic attacks and cerebral infarction.

Aggravated retinopathy

Hypoglycemia in diabetic patients may aggravate retinopathy.

Falls and injuries

During hypoglycemic episodes, patients are prone to fall and sustain fall injuries, but such injuries are among the easily overlooked damages of hypoglycemia.

Consultation

Department of Medicine

Emergency Department

In the case of more serious conditions such as impaired consciousness, slurred speech, and limb weakness, you should consult a doctor immediately or call the 120 emergency number to avoid delaying treatment.

Endocrinology

For diabetic patients with symptoms of hypoglycemia, all hypoglycemic drugs should be stopped immediately, oral sugar-containing substances should be taken, and timely medical care should be sought to adjust the treatment plan.

General Internal Medicine

Anyone with recurrent hypoglycemia symptoms is advised to consult a doctor promptly.

Preparation

Consultation: Registration, Preparation of documents, Frequently Asked Questions

Tips for Consultation

Patients suspected of hypoglycemia should be given oral sugary substances (e.g., sugar-sweetened beverages, sugar cubes, cookies, etc.) immediately, and their blood glucose should be measured if possible.

If cardiac arrest has occurred, cardiopulmonary resuscitation (CPR) should be performed immediately (if you do not know how to perform CPR, you should call 120 immediately and complete it over the phone).

For patients with epileptiform seizures, sit or lie down in a stable position, keep the airway open, and do not forcefully immobilize the patient’s limbs to avoid injury.

Checklist for preparing for medical care

Particular attention needs to be paid to the time of symptom onset, special manifestations, etc.

Are there any symptoms such as hunger, palpitation, cold sweat, shaking hands before coma?

Is there any impairment of consciousness and to what extent?

Have similar symptoms occurred before?

When did the symptoms start and how long did they last?

Are there any aggravating or relieving factors for the symptoms?

Any previous history of diabetes mellitus, insulinoma, etc.?

Any previous history of cerebral infarction, cerebral hemorrhage, tumor, etc.?

Any recent adjustments to medication regimen?

Any recent dieting?

Did you exercise before the onset of the disease?

Examination results in the past six months, etc., which can be brought to the doctor

Laboratory tests: blood routine, blood biochemistry, blood glucose (the last measurement time and value).

Imaging: head CT or magnetic resonance, chest CT or chest X-ray.

Other tests: electrocardiogram, echocardiogram, etc.

Medication use in the last three months, if available, bring the box or package with you to the doctor’s office

Insulin: Glucagon, Mentholatum, Dieter’s insulin, etc.

Glucose-lowering drugs: glibenclamide, glimepiride, metformin, pioglitazone, selegiline, ligustine, etc.

Psychotropic drugs: eszopiclone, paroxetine, olanzapine, etc.

Diagnosis

Diagnosis is based on

Medical history

History of dieting, fasting exercise, and strenuous exercise.

Diabetes mellitus with recent glucose-lowering medication adjustments.

History of systemic chronic diseases.

Clinical manifestations

Palpitations.

Sweating.

Anxiety, irritability.

Significant hunger.

Forgetfulness.

Weakness of limb movement, slurred speech.

Blurred vision, tinnitus.

Irritability, convulsions.

Varying degrees of impaired consciousness, such as drowsiness and coma.

Increased heart rate and pulse.

Pallor.

Impaired limb movement, which may manifest as hemiparesis and other signs similar to cerebral infarction.

Laboratory Tests

Blood glucose: Fingertip blood glucose and venous blood glucose drop to below 2.8mmol/L mostly with severe hypoglycemic symptoms; below 2.2mmol/L, cerebral dysfunction can occur. However, there are large individual differences [6].

Insulin, C-peptide, insulin antibody and other tests: to clarify the etiology of hypoglycemia, which is less frequently measured in the acute stage.

Blood biochemistry: it is meaningful to determine the severity of the disease, including liver and kidney function, electrolytes, amylase, lipase and so on. If the patient is in coma, there are mostly elevated creatinine, liver enzymes, bilirubin, amylase, lipase.

Arterial blood gas analysis: to determine whether there is hypoxia, respiratory depression.

Blood toxin test/urine metabolite test: to determine whether there is overdose of hypoglycemic drugs.

Imaging

Echocardiography: Used to exclude cardiac disease and assess the prognosis of the disease, most patients are normal, but may appear different depending on the severity of the disease.

Head CT/Magnetism: used to identify acute cerebrovascular disease.

Electrocardiogram

Used to identify cardiovascular disease.

Differential Diagnosis

Cerebral infarction, cerebral hemorrhage

Similarity: both may have weakness of limb movement, slurred speech, and different degrees of consciousness disorder.

Differences: Before the occurrence of coma in cerebral infarction and cerebral hemorrhage, there is no typical hypoglycemia manifestation, and the symptoms do not improve after supplementing sugar. Head CT, magnetic resonance examination can be differentiated.

Diabetic ketoacidosis

Similarity: both have a history of diabetes mellitus, manifested by different degrees of impaired consciousness.

Differences: patients with diabetic ketoacidosis have a rotten apple odor on expiration, positive urine ketone bodies, blood gas analysis suggestive of metabolic acidosis, and blood glucose is usually higher than normal.

Hyperosmolar diabetic coma

Similarities: both have a history of diabetes mellitus, manifested by varying degrees of impaired consciousness.

Differences: Hyperosmolar diabetic coma patients tend to have sluggish expression, drowsiness, gradually deteriorating to coma, blood glucose is usually higher than 33.3mmol/L, and blood sodium is high.

Treatment

Treatment aim: correct hypoglycemia, reduce mortality.

Treatment principle: raise blood glucose to normal or slightly higher level as soon as possible, and release the causes of hypoglycemia.

General treatment

For hypoglycemic comatose patients, cardiac monitoring and maintenance of effective circulation should be carried out.

Pay attention to the patient’s state of mind, heart rate, respiration, inlet and outlet, etc., and apply pressure-raising drugs if necessary.

Keep the airway open.

Monitor blood glucose.

Medication

Glucose

Fast and effective, often as the first choice of drugs.

Clinically, 50% dextrose injection is mostly applied to flush into the vein to monitor blood glucose, which can be applied repeatedly, and then 10% dextrose injection can be applied to maintain blood glucose by intravenous drip.

Adverse reactions: 50% dextrose injection can cause intravenous drip extravasation, phlebitis, etc., resulting in local redness, swelling and pain.

Glucagon

Can antagonize insulin and act to increase blood glucose. It is fast-acting, but the maintenance time is short.

Commonly used subcutaneous, intramuscular, intravenous injection.

Short maintenance time, need to monitor blood glucose, advise the patient to eat as soon as possible or apply enteral nutrition, so as to avoid recurrence of hypoglycemia.

Glucocorticoid

Used for those who have cerebral edema, can reduce cerebral edema.

Commonly used drugs include dexamethasone and methylprednisolone.

Prognosis

Cure

With timely diagnosis and treatment, most of the cases have a good prognosis.

Coma lasting more than 6 hours can lead to irreversible brain damage or even death.

Prognostic factors

The following factors can affect the prognosis of patients with hypoglycemic coma:

Duration of hypoglycemia.

Age.

Underlying disease.

Hazards.

Patients with prolonged coma duration may experience irreversible brain damage and death. Even if resuscitation is successful, sequelae may still occur [11], such as ischemic-hypoxic encephalopathy, secondary epilepsy, and organ dysfunction.

Neonates with hypoglycemia that is not corrected in time may have extensive brain damage, leading to mental retardation, etc. Adult patients may have sequelae such as amnesia, cognitive dysfunction, and behavioral abnormalities.

Daily

Daily management

Patients with diabetes mellitus should carry out lifestyle management such as diet and exercise under the guidance of doctors.

Monitor blood glucose routinely.

Use or adjust the glucose-lowering program as prescribed by the doctor.

Abstain from alcohol.

Meals must be taken after insulin injection.

Those who lose weight should choose exercise to lose weight, not excessive dieting.

Disease monitoring

Regular endocrinology clinic follow-up.

Monitor the patient’s mental status, cognitive function, behavior, memory, and mood.

Diabetic patients should monitor blood glucose as required by the endocrinologist.

Follow-up review

Follow the doctor’s instructions to the hospital for review.

Blood glucose, insulin, C-peptide and other tests may be needed.

Prevention

Keep sugar cubes and cookies with you to take as soon as possible when symptoms such as palpitations, sweating and shaking hands occur, and seek medical advice as soon as possible.

Avoid strenuous exercise on an empty stomach.

Diabetic patients should strictly follow the doctor’s instructions to adjust the dosage of hypoglycemic drugs, do not adjust the medication according to the symptoms or blood glucose level without authorization.