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 both of which can contribute to the development of hypoglycemia.

Central nervous system findings are the most prevalent. These include headache, confusion, personality changes, palpitations, adrenergic symptoms, sweating, anxiety, nervousness and tremulousness. Hunger and nausea are also prevalent findings.

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.

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.

Other causes include the following: GI Surgery, hepatic disease, islet cell tumor or extrapancreatic tumors, exercise in diabetic patients, pregnancy, adrenal insufficiency, enzyme deficiencies, hypopituitarism, starvation, and sepsis.

If the cause of hypoglycemia is other than oral hypoglycemic agents or insulin in a diabetic patient, other lab tests may be necessary. C-peptide is elevated in insulinoma, normal or low with exogenous insulin, and elevated with oral sulfonylureas. Liver function tests, serum insulin, and cortisol and thyroid levels should be checked. A source of infection should be ruled out by utilizing the usual screening tests: complete blood count, urine analysis, chest x-ray and blood cultures.

The initial approach should include the following: ABCs, intravenous (IV) access, oxygen, monitoring, and Accucheck. Administration of glucose as part of the initial evaluation of altered mental status often corrects hypoglycemia.

Treatment should not be withheld while waiting for a laboratory glucose value. Because the brain uses glucose as its primary energy source, neuronal damage may occur if treatment of hypoglycemia is delayed. A hyperglycemic patient with an altered mental status may receive a bolus of glucose. This procedure is unlikely to harm the patient with high glucose; however, the delay in giving glucose to the hypoglycemic patient may be detrimental.

Once the diagnosis of hypoglycemia is made, search carefully for the cause in the previously healthy patient. In the diabetic patient, search diligently for the cause (e.g.: medication changes, dietary changes, new metabolic changes, recent illness, occult infection) of the episode.

Admission is reserved for patients with no known cause or no previous episodes of hypoglycemia, for overdose, accidental ingestion, or therapeutic misadventures with oral hypoglycemics. The length of admission and observation is based on the ingested oral hypoglycemic agent.

Unrecognized infection causing hypoglycemia in diabetic patients may result in recurrent hypoglycemic spells or progression of the infection. Therefore, when hypoglycemia is diagnosed, a search for possible infection should ensue.

Lastly, clinicians make a major mistake when they send home a patient who has become awake and alert after the administration of glucose, when the cause for the hypoglycemia is oral hypoglycemic medications. These patient usually drop their blood glucose again, and can lose consciousness and suffer related complications such as aspiration or fractures and head injury secondary to falling.