Diabetic Emergencies and Altered Mental Status

Altered mental status — core concepts

Altered mental status (AMS) covers a broad spectrum of abnormal responsiveness, thought and mood, from mild anxiety to unconsciousness. Its causes fall into three groups: structural damage, such as a traumatic brain injury (TBI); chemical changes, such as toxins; and metabolic changes, such as a lack of oxygen or glucose. However subtle it may be, altered mental status is always a serious finding. Wakefulness is governed by the reticular activating system (RAS), which needs oxygen, glucose and water to function, and a deficiency of any of the three causes rapid and serious AMS.

Assessment begins with safety, because patients with altered mental status can be unpredictable. In the primary assessment, remember that hypoxia and carbon dioxide (CO2) retention are common causes of AMS, and consider shock as well. Establish the AVPU level early, and refine it later with a Glasgow Coma Scale (GCS) score. The secondary assessment includes a full history, interviews with bystanders and family, a review of the patient's medications, and a search for medical alert items.

Diabetes mellitus

Glucose is the body's basic energy source. To cross most cell membranes it needs insulin; brain cells are the exception and take up glucose without it. The pancreas secretes insulin when the blood glucose rises above roughly 90 mg/dL. Diabetes mellitus is the disease in which this system fails, and it takes two forms, compared in the table below.

Table 22.1Diabetes mellitus

Hypoglycemia vs. hyperglycemia

The two diabetic emergencies are opposites in cause and presentation. The table below contrasts them.

Table 22.2Hypoglycemia vs. hyperglycemia

Hypoglycemia has several common causes: too much insulin or oral medication, reduced food intake, over-exercise, vomiting a meal, or an increased metabolic rate. On the other side, diabetic ketoacidosis (DKA) and HHNS are both forms of severe hyperglycemia. You do not need to distinguish them in the field, because the treatment is the same.

Both hypoglycemia and hyperglycemia can mimic intoxication. Always suspect a diabetic cause behind apparent drunkenness.

Blood glucose meters & treatment

When a diabetic patient has altered mental status, measure the blood glucose, and generally use your own device rather than the patient's own meter. A reading below 70 mg/dL is the usual threshold for hypoglycemia, and it is where treatment starts in a symptomatic patient. Protocols vary on the exact number — some services use 60 — so learn the figure your own protocol uses and treat that as authoritative on the truck. The number matters less than the pairing: a low reading in a patient who is symptomatic is what you are treating, and a patient who is clearly hypoglycemic gets treated even if the meter reads a little above the line. Below 50 mg/dL, altered mental status is often significant and the patient may be unable to take oral glucose safely. A reading above 140 mg/dL is hyperglycemia, and above 300 mg/dL the patient becomes dehydrated and the symptoms become more serious.

Low glucose is more dangerous than high glucose. Giving glucose helps a hypoglycemic patient and does no meaningful harm to a hyperglycemic one, which is why, when you are uncertain, giving it is the safer default. Oral glucose has three criteria, all of which must be met:

• The patient has a history of diabetes.
• The patient has an altered mental status.
• The patient is awake enough to swallow safely.

If the patient loses consciousness at any point, stop giving oral glucose and secure the airway.

Seizure disorders

A seizure is a sudden change in sensation, behavior or movement produced by irregular electrical activity in the brain, which may follow injury, infection or disease. A seizure is a sign, not a disease in itself.

The tonic-clonic (grand mal) seizure passes through three phases. In the tonic phase, which lasts up to 30 seconds, the body becomes rigid and breathing may stop. In the clonic phase, which lasts 1 to 2 minutes, the patient jerks violently, may foam at the mouth, and the face becomes cyanotic. In the postictal phase the patient is drowsy and confused and gradually clears; a transient one-sided weakness is possible.

The most common cause of seizures in adults is a missed dose of antiseizure medication. Febrile seizures are most common between 6 months and 3 years of age. The other causes include hypoxia, stroke, TBI, toxins, hypoglycemia, brain tumor and infection.

Seizure management

While the patient is convulsing, your job is to prevent injury, not to stop the seizure. Position the patient on the floor or ground, side-lying if there is no suspicion of spine injury. Loosen restrictive clothing, clear away nearby objects that could cause harm, and protect the patient from injury. Do not hold the patient still, and never place anything in the mouth.

After the convulsions end, protect the airway, suctioning if the patient is drooling, and place the patient in the recovery position if there is no spine injury. Give oxygen guided by pulse oximetry, and assess and treat any injuries the seizure itself caused.

Status epilepticus is either 2 or more seizures in a row without a full recovery of consciousness between them, or a single seizure lasting longer than 5 minutes. It is a high-priority, life-threatening condition that calls for immediate transport and possibly an ALS intercept.

Stroke

An ischemic stroke, the most common type, occurs when a clot or embolism blocks an artery in the brain. A hemorrhagic stroke occurs when a vessel ruptures, often as a result of chronic hypertension or an aneurysm. Because motor control is crossed, damage on one side of the brain produces hemiparesis, weakness on one side of the body.

The Cincinnati Prehospital Stroke Scale consists of three tests, set out in the table below.

Table 22.3Stroke

An abnormal result on any one of the three tests indicates roughly a 70% chance of acute stroke. A transient ischemic attack (TIA) produces the same symptoms, but they fully resolve within 24 hours. You cannot distinguish a TIA from a stroke in the field, so always treat the patient as a stroke. Several conditions mimic stroke: hypoglycemia, which is why you should check the glucose if you are allowed to, postictal weakness after a seizure, and infection or sepsis in the elderly.

Management consists of calm reassurance, oxygen if the SpO2 is below 94% or the patient is in distress, and transport to a stroke-capable facility. Determining and documenting the exact time of symptom onset, or the time the patient was last known well, is one of the most valuable things an EMT can do, because thrombolytic therapy typically requires an onset within 3 to 4.5 hours.

Dizziness & syncope

Syncope is a brief loss of consciousness (LOC) with spontaneous, rapid recovery once the patient is supine. Its causes fall into 4 categories: cardiovascular, such as a dysrhythmia or a vasovagal episode; hypovolemic, such as dehydration or internal bleeding, including ectopic pregnancy, abdominal aortic aneurysm (AAA) and gastrointestinal (GI) bleeding; structural or metabolic, such as stroke, seizure, hypoglycemia and inner-ear problems; and environmental or toxicologic, such as alcohol, carbon monoxide (CO) and panic attacks.

Management is straightforward: lay the patient flat, loosen tight clothing, give oxygen according to saturation and distress, call for ALS if there are signs of instability, and treat any injuries from the fall. Most patients with syncope should be evaluated by ALS, because a cardiac cause always warrants consideration.