Chap 19 Flashcards
RAS
Reticular Activating System- series of neurological circuits in the brain that control the functions of staying awake, paying attention and sleeping
The brain tissue of the RAS has simple requirements to function properly and thereby keep a person alert and oriented. oxygen is needed to perfuse brain tissue, glucose is needed to nourish brain tissue and water is needed to keep brain tissue hydrated. Other harm to the brain such as trauma, infection, and chemical toxins (as in overdose and substance abuse)
Altered mental status can result from a primary brain problem, such as a stroke or symptom of a problem within another system such as hypoxia due to asthma.
Most common cause of altered mental status
Hypoxia
Baseline level of consciousness
Ask parents, family member, or bystanders that would know if this is the patients normal acting behavior
Glucose
a form of sugar, the body’s basic source of energy
Comes from sugar we eat or carbohydrates that the digestive system will convert to glucose
The glucose molecule is large and will not pass into most cells without the assistance of insulin. The pancreas secretes insulin when the blood glucose rises above 90mg/dL. insulin binds to receptor sites on cells- especially those in the liver and muscles-and allows the large glucose molecule to pass into the cells
Patients who are diabetic
- Don’t produce insulin
- Don’t produce enough insulin
- Have a body that has become resistant to the insulin that is produced
Insulin-Glucose relationship has been described as the “lock and key” mechanism
insulin
A hormone produced by the pancreas or taken as a medication by many diabetics
Insulin and the pancreas
Within the pancreas, specialized clusters of cells called the islets of Langerhans secrete insulin. Brain cells do not require insulin to move glucose from the bloodstream.
Diabetes Mellitus
Also called “sugar diabetes” or just diabetes.
1 in 17 or 16 million Americans have diabetes
-Underproduction of insulin or inability of the bodies cells to use insulin properly
Type 1 diabetes
Formerly known as insulin-dependent diabetes
Occurs when pancreatic cells fail to function properly and insulin is not secreted normally.
Synthetic insulin is used to supplement
Type 2 diabetes
Formerly known as non-insulin-dependent diabetes
Occurs when the body’s cells fail to use insulin properly. The pancreas may be secreting enough insulin but the body is unable to use it to move glucose out of the blood and into the cells. Patients with type 2 diabetes can often control their condition with diet and/or oral antidiabetic medications
Hypoglycemia
Low blood sugar
Caused by
- Takes too much insulin thereby transferring glucose into the cells too quickly and causing rapid depletion of available sugar
- Reduces sugar intake by not eating
- Over exercises or overexerts himself, thus using sugars faster than normal
- Vomits a meal, emptying the stomach of sugar as well as other food
- Increases the metabolic rate in conditions such as fever or shivering
- Rapid onset
- Abnormal behavior that often mimics a drunken stupor
- Responds with a fight or flight response. The sympathetic nervous system signals the liver to release glycogen (a form of stored sugar) in an attempt to raise blood glucose levels. Signs of this sympathetic discharge, which are very common, including pale, sweaty skin; tachycardia; and rapid breathing. Seizures can occur as a result of altered brain function.
Treatment
-Oral glucose to patient with altered mental status, conscious (able to swallow), and has a history of diabetes
Hyperglycemia
High blood sugar
Hyperglycemia is usually caused by a decrease in insulin which leaves sugar in the bloodstream rather than helping it to enter the cells. The insulin deficiency may be due to the body’s inability to produce insulin or may exist because insulin injections were forgotten or not given in sufficient quantity. Infection, stress or increasing dietary intake can also be a factor
- typically develops over days and even weeks-in contrast to the typical rapid onset of hypoglycemia. Glucose levels in the blood creep up while the cells of the body begin to starve for sugar. As blood sugar levels increase, the patient may complain of chronic thirst and hunger. In an attempt to rid the blood of excess sugar, the body will increase urination. Nausea is also a frequent complaint
- Extremely high levels of sugar in the blood begin to draw water away from the body’s cells, potentially resulting in profound dehydration. Starving body cells begin to burn fats and proteins in a manner that results in excessive waste products being released into the system. These waste products build up and combine with dehydration to cause a condition called diabetic ketoacidosis (DKA). A person who has diabetic ketoacidosis will commonly have a profoundly altered mental status. He will also have the signs and symptoms of severe shock, caused by dehydration. A waste product of DKA is ketones. This complication will make breathing rapid and often a fruity, acetone odor on his breath.
Glucose readings
Value less than 60mg/dL- in a symptomatic diabetic patient with a mild alteration in mental status or who is diaphoretic is typically of hypoglycemia. Patients values less than 50mg/dl will typically have significant alterations in mental status that may include complete unresponsiveness. Often will be unable to receive glucose safely.
A value of greater than 140 indicates hyperglycemia. Patients in the mid and high 100s are often without acute symptoms, although over time this level of hyperglycemia can cause damage to various organs. Levels greater than 300, especially for a prolonged time, may experience dehydration and other more serious symptoms
If reading is inconsistent with patients symptoms, potential of inaccurate results
Sometimes a reading of High/ HI means excess of 500mg/dL and LOW less than 15mg/dL
Hypoglycemia and Hyperglycemia compare
Onset- Hyperglycemia usually has a slower onset, whereas hypo tends to come on suddenly. this is because some sugar still reaches the brain in hyper. With hypo, it is possible that no sugar reaching the brain. Seizures may occur
Skin- Hyper patients often have warm, red, dry skin. Hypo patients have cold, pale, moist, or clammy skin
Breath- Hyper often have acetone breath. Hyper also breathe very deeply and rapidly as though they have just run a race. Dry mouth, intense thirst, abdominal pain and vomiting are all common signs and symptoms
Rule of thumb for diabetics
“Sugar for everyone”
Sepsis
Infection, especially a severe, systemwide response to infection
One of the most dangerous causes of altered mental status. Normally when an infection occurs, the body takes steps to fight the invaders locally at the site of infection. Blood vessels dilate to allow white blood cells to respond and capillaries become more permeable to allow fluid to dilute toxins released by the invaders. Severe sepsis occurs when these steps move from the local site of infection and become a systemic problem (systemic inflammatory response). The vasodilation that once helped move white blood cells now causes a severe drop in pressure within the cardiovascular system. Distributive shock results. The capillary permeability that helped dilute toxins now results in a massive fluid shift out of the cardiovascular system, causing hypovolemic shock. These two combined factors can lead to massive hypo perfusion of the body tissues. Finally if the infection becomes severe enough, the offending microbes, such as bacteria, can release toxins that harm cardiac out-put, furthering the shock state.
Three types of infections most commonly associated with severe sepsis are respiratory infections and pneumonia, urinary tract infections (UTI’s), and skin/wound infections.
Evidence of severe sepsis
- Altered mental status
- Increased heart rate
- Increased respiratory rate
- Low blood pressure
- High blood glucose levels
- Decreased capillary refill time
Always suspect sepsis in patients with altered mental status and recent infections