Introduction
Background
Hypoglycemia is considered present when serum glucose level is less than 50 mg/dL. However, more specifically, it is defined as a decrease in the blood glucose level or its tissue utilization that results in demonstrable signs or symptoms. These signs or symptoms usually include altered mental status and/or sympathetic nervous system stimulation. The glucose level at which an individual becomes symptomatic is highly variable.
Pathophysiology
The organ systems that manifest the signs and symptoms of hypoglycemia are the central and autonomic nervous systems.
Hypoglycemia can be due to alimentary problems, idiopathic causes, fasting, insulinoma, endocrine problems, extrapancreatic causes, hepatic disease, and miscellaneous causes.
Mortality/Morbidity
Delay in treatment can result in profound sequelae, including death.
- Acute sequelae include coma, cardiac dysrhythmia, and death.
- The risk of permanent neurologic deficits increases with prolonged hypoglycemia; such deficits can include hemiparesis, memory impairment, diminished language skills, decreased abstract thinking capabilities, and ataxia.
- Because the consequences of hypoglycemia can be devastating and an antidote is readily available, diagnosis and treatment must be rapid in any patient with suspected hypoglycemia, regardless of the cause.
Sex
Females are affected by hypoglycemia more than males.
Age
Hypoglycemia affects predominantly older adults.
Clinical
History
- Patients often have a history of diabetes mellitus.
- A history of insulin usage or ingestion of an oral hypoglycemic agent may be known, and possible toxic ingestion should be considered.
- Inquire if the patient is taking any new medications.
- Obtaining an accurate medical history may be difficult if the patient's mental status is altered.
- The medical history may include diabetes mellitus, renal insufficiency/failure, alcoholism, hepatic cirrhosis/failure, other endocrine diseases, or recent surgery.
- The patient's medication and drug history should be reviewed carefully for potential causes of hypoglycemia.
- The social history may include ethanol intake and nutritional deficiency.
- Review systems for weight reduction, fatigue, somnolence, nausea and vomiting, and headache.
- Look for other symptoms suggesting infection.
- Central nervous system
- Headache
- Confusion
- Personality changes
- Cardiovascular system - Palpitations
- GI symptoms
- Hunger
- Nausea
- Belching
- Adrenergic symptoms
- Sweating
- Anxiety
- Tremulousness
- Nervousness
Physical
Physical findings are nonspecific in hypoglycemia and generally are related to the central and autonomic nervous systems.
- Assess vital signs for hypothermia, tachypnea, tachycardia, hypertension, and bradycardia (neonates).
- The head, eyes, ears, nose, and throat (HEENT) examination may indicate blurred vision, pupils normal to fixed and dilated, icterus (usually cholestatic due to hepatic disease), and parotid pain (due to endocrine causes).
- Cardiovascular disturbances may include tachycardia (bradycardia in neonates), hypertension or hypotension, and dysrhythmias.
- Respiratory disturbances may include dyspnea, tachypnea, and acute pulmonary edema.
- GI disturbances may include nausea and vomiting, dyspepsia, and abdominal cramping.
- Skin may be diaphoretic and warm or show signs of dehydration with decrease in turgor.
- Neurologic conditions include coma, confusion, fatigue, loss of coordination, combative or agitated disposition, stroke syndrome, tremors, convulsions, and diplopia.
Causes
- Causes of hypoglycemia are varied, but it is seen most often in diabetic patients.
- Hypoglycemia may result from medication changes or overdoses, infection, diet changes, metabolic changes over time, or activity changes; however, no acute cause may be found.
- Careful consideration should be given to all diabetic patients presenting with hypoglycemia. New medications, activity changes, and infection should be considered.
- Early in the course of non–insulin-dependent diabetes, patients may experience episodes of hypoglycemia several hours after meals. The symptoms generally are brief and respond spontaneously.
- Patients with no prior history of hypoglycemia require a complete workup to find a potentially treatable disease.
- Drugs that may be related to hypoglycemia include the following: oral hypoglycemics, sulfonamide, phenylbutazone, insulin, bishydroxy coumarin, salicylates, p-aminobenzoic acid, propoxyphene, haloperidol, stanozolol, ethanol, hypoglycin, carbamate insecticide, disopyramide, isoniazid, methanol, methotrexate, pentamidine, sulfonamide, tricyclic antidepressants, cytotoxic agents, organophosphates, propranolol plus ethanol, didanosine, chlorpromazine, quinine, sulfa drugs, fluoxetine, sertraline, fenfluramine, trimethoprim, 6-mercaptopurine, thiazide diuretics, thioglycolate, tremetol, ritodrine, disodium ethylenediaminetetraacetic acid (EDTA), clofibrate, angiotensin converting enzyme (ACE) inhibitors, and lithium.
- Factitious hypoglycemia or self-induced hypoglycemia can be seen in health care workers or in relatives who care for diabetic family members at home. Further discussion, including the diagnostic use of C-peptide levels and hemoglobin A1C, can be found in the articles Diabetes Mellitus, Type 1 - A Review and Diabetes Mellitus, Type 2 - A Review.
- Other causes include the following:
- GI surgery
- Idiopathic
- Hepatic disease
- Islet cell tumor/extrapancreatic tumor
- Exercise (in diabetic patients)
- Pregnancy
- Renal glycosuria
- Ketotic hypoglycemia of childhood
- Adrenal insufficiency
- Hypopituitarism
- Enzyme deficiency
- Large tumors (eg, mesenchymal tumors, epithelial tumors, endothelial tumors)
- Sepsis
- Starvation
- Artifact
More on Hypoglycemia |
 Overview: Hypoglycemia |
| Differential Diagnoses & Workup: Hypoglycemia |
| Treatment & Medication: Hypoglycemia |
| Follow-up: Hypoglycemia |
| References |
| Next Page » |
References
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Further Reading
Keywords
hypoglycemia, low blood sugar, low glucose, glucopenia, decrease in the blood glucose level, insulinoma, coma, cardiac dysrhythmia, confusion, convulsions, diabetes, non–insulin-dependent diabetes, oral hypoglycemics, islet cell tumor, extrapancreatic tumor,insulin, palpitations, nausea, sweating, anxiety, diabetes mellitus type 1, diabetes mellitus type 2
