Acidosis
Acidosis may be caused by an overproduction of acid in the blood or an excessive loss of bicarbonate from the blood (metabolic acidosis). Or it may be caused by a buildup of carbon dioxide in the blood (respiratory acidosis). If an increase in acid overwhelms the body's acid-base control systems, the blood becomes acidic. Which of the following organs tries to compensate for the excess acid in the blood?
Heart
B.
Kidneys
C.
Liver
D.
Spleen
Answer: B: Kidneys. The kidneys try to compensate by excreting more acid in the urine. If the kidneys are not functioning normally, they are not able to excrete sufficient amounts of acid in the urine. As a result, production of even normal amounts of acid may lead to acidosis.
Which of the following characteristics is most likely to differentiate chronic respiratory alkalosis from acute respiratory alkalosis?
A.
Hyperpnea is often the only sign
B.
No distinctive signs are present
C.
Syncope is a common symptom
D.
Tachypnea is often the only sign
Answer: B: No distinctive signs are present. Chronic respiratory alkalosis has no distinctive signs and is usually asymptomatic. A, C, and D are characteristics of acute respiratory alkalosis.
Acidity and alkalinity are expressed on the pH scale, which ranges from 0 (strongly acidic) to 14 (strongly basic, or alkaline). Which of the following most closely describes the normal pH of the blood?
A.
Slightly acidic
B.
Slightly basic
C.
Strongly acidic
D.
Strongly basic
Answer: B: Slightly basic. Usually, the body maintains the pH of blood close to 7.40. A, C, and D: An increase or decrease in blood pH may indicate a disorder.
Which of the following disorders can cause dehydration by excessive urination?
A.
Atherosclerosis
B.
Diabetes mellitus
C.
High blood pressure
D.
Hyperthyroidism
Answer: B: Diabetes mellitus. Atherosclerosis, high blood pressure, and hyperthyroidism do not increase urine excretion.
Which of the following is a major cause of respiratory acidosis?
A.
Anxiety
B.
Fever
C.
Low oxygen levels
D.
Opioid overdose
Answer: D: Opioid overdose. People can develop respiratory acidosis when their breathing is slowed because of oversedation due to opioids (narcotics) or strong drugs that induce sleep (sedatives). A, B, and C: Anxiety or panic attacks, fever, and low levels of oxygen in the blood are major causes of respiratory alkalosis, which is the opposite of acidosis. In alkalosis, the blood has too much base (or too little acid), rather than too much acid (or too little base), as occurs in acidosis.
In patients with CNS disorders who are experiencing respiratory alkalosis, increasing inspired CO2 through rebreathing is contraindicated because the value of which of the following is already likely to be below normal?
A.
CSF pH
B.
Hydrogen ion
C.
Ionized calcium
D.
O2 gradient
Answer: A: CSF(cerebrospinal fluid) pH. Rebreathing may be dangerous in patients with CNS disorders who are experiencing hyperventilation because their CSF pH is most likely to be below normal. Rebreathing is not contraindicated in patients with CNS disorders if B, C, and D are below normal.
A solution containing which of the following household substances can neutralize acid in the body that is produced from food and is recommended for people with type 1 or 2 renal tubular acidosis?
A.
Baking soda
B.
Cream of tartar
C.
Lemon juice
D.
Salt
Answer: A: Baking soda. Baking soda, or sodium bicarbonate, when mixed with water, can neutralize acid that is produced from food and treat the symptoms of renal tubular acidosis. Choices B, C, and D: These substances will not neutralize the acid in the body caused by renal tubular acidosis.
Which of the following symptoms suggests severe dehydration?
A.
Confusion
B.
Dry mouth
C.
Thirst
D.
Reduced urine production
Answer: A: Confusion. Dry mouth, thirst, and decreased urine production are symptoms of mild to moderate dehydration. In severe dehydration, the sense of thirst may actually decrease.
Which of the following disorders can lead to a form of metabolic acidosis called ketoacidosis (the buildup of ketoacids)?
A.
An adrenal tumor
B.
Cushing syndrome
C.
Hypothyroidism
D.
Diabetes
Answer: D: Diabetes. The body produces excess acid in poorly controlled type 1 diabetes mellitus (diabetic ketoacidosis). A and B: An overactive adrenal gland (due to Cushing syndrome or some adrenal tumors) causes respiratory alkalosis (too much base in the blood or too little acid), not acidosis.
Respiratory alkalosis develops when rapid, deep breathing (hyperventilation) causes too much carbon dioxide to be expelled from the bloodstream. Which of the following is the most common cause of hyperventilation and, thus, of respiratory alkalosis?
A.
Anxiety
B.
Fever
C.
Low levels of oxygen in the blood
D.
Pain
Answer: A: Anxiety. The most common cause of hyperventilation and thus respiratory alkalosis is anxiety. B. C, and D: Other causes of hyperventilation and consequent respiratory alkalosis include pain, low levels of oxygen in the blood, and fever.
Which of the following symptoms can lead to chronic kidney disease and is only present in people who have type 1 renal tubular acidosis?
A.
Bone pain
B.
Fragile bones
C.
Kidney stones
D.
Mild dehydration
Answer: C: Kidney stones. People with type 1 renal tubular acidosis are more likely to have calcium deposits, which then lead to kidney stones and can eventually lead to chronic kidney disease. Choices A, B, and D: These are all symptoms that can occur in people with type 1 or type 2 renal tubular acidosis.
Which of the following organs is particularly susceptible to damage due to overhydration?
A.
Liver
B.
Brain
C.
Heart
D.
Kidneys
Answer: B: Brain cells are particularly susceptible to overhydration and to low sodium levels in the blood. When overhydration occurs slowly and is mild or moderate, brain cells have time to adapt, so only mild symptoms (if any), such as distractibility and lethargy may ensue. When overhydration occurs quickly or when dehydration is severe, confusion, seizures, or coma may develop. A, C, and D: Other organs may be affected less critically than the brain.
Several symptoms may occur at the onset of ketoacidosis. Which of the following is a symptom often experienced by children with ketoacidosis but usually not by adults?
A.
Abdominal pain
B.
Excessive thirst
C.
Fatigue
D.
Weight loss
A
Which of the following conditions requires urine chloride assessment, as well as assessment of serum electrolytes, BUN, and creatinine, in a patient with volume depletion?
A.
Burns
B.
Diarrhea
C.
Metabolic alkalosis
D.
Renal failure
Answer: C: Metabolic alkalosis. A, B, and D: Standard serum electrolyte testing may be done.
In renal tubular acidosis, the kidney tubules malfunction, resulting in excess levels of acid in the blood. This condition may be permanent, or it may be intermittent. Which of the following types of people are most likely to have permanent renal tubular acidosis?
A.
People who have inherited the disorder
B.
People who take diuretics that conserve the body’s potassium
C.
People with diabetes
D.
People with sickle cell disease
Answer: A: People who have inherited the disorder. Renal tubular acidosis may be a permanent, inherited disorder in children. Choices B, C, and D: Renal tubular acidosis may be an intermittent or temporary disorder in people who take diuretics that conserve the body’s potassium, people with diabetes, or people with sickle cell disease.
Overhydration can occur when people drink much more water than their body needs. Overhydration can also develop if people have a disorder that decreases the body’s ability to excrete water or increases the body's tendency to retain water. Which of the following happens if someone with normally functioning kidneys drinks too much water?
A.
Nothing bad unless the person is an athlete
B.
Low levels of sodium in the blood
C.
Usually nothing because normally functioning kidneys excrete the excess water
D.
Confusion or seizures
Answer: C: Usually nothing because normally functioning kidneys excrete the excess water. To exceed the body’s ability to excrete water, a young adult with normal kidney function would have to drink more than 6 gallons of water a day on a regular basis. A: Athletes drink a lot of water but usually do not develop overhydration. B and D: Overhydration may lead to these consequences, but drinking large amounts of water usually does not cause overhydration if the pituitary gland, kidneys, liver, and heart are functioning normally.
Diabetic ketoacidosis is a complication of diabetes. It occurs mostly in people with type 1 diabetes. Diabetic ketoacidosis occurs when a lack of insulin prevents glucose in the bloodstream from entering the cells. Without adequate glucose, the cells burn fat for energy, producing compounds called ketones. Ketones supply some energy, but they also make the blood too acidic. There are several causes of ketoacidosis. Which of the following is a cause of ketoacidosis?
A.
Consumption of high amounts of sugar
B.
Failure to take insulin by a person with type 1 diabetes
C.
Taking too much insulin
D.
Not getting enough exercise
B
Metabolic alkalosis develops when the body loses too much acid or gains too much base. Loss of enough potassium to cause metabolic alkalosis may result from which of the following types of drug?
A.
Chemotherapy drugs
B.
Opioids
C.
Diuretics
D.
Proton pump inhibitors
Answer: C: Diuretics. Loss of potassium sufficient to cause metabolic alkalosis may result from an overactive adrenal gland or the use of diuretics (such as thiazides or furosemide).
The blood's acid-base balance is precisely controlled because even a minor deviation from the normal range can severely affect many organs. The body uses different mechanisms to control the blood's acid-base balance. Which of the following is one of the main mechanisms to control acid-base balance?
A.
Breathing
B.
Digestion
C.
Heart rate
D.
Sleeping
Answer: A: Breathing. Carbon dioxide (a mildly acidic waste product) is carried to the lungs, where it is exhaled. As carbon dioxide accumulates in the blood, the pH of the blood decreases (acidity increases). The amount of carbon dioxide exhaled, and consequently the pH of the blood, increases as breathing becomes faster and deeper. By adjusting the speed and depth of breathing, the brain and lungs are able to regulate the blood pH minute by minute. The kidneys have some ability to alter the amount of acid or base that is excreted, but because the kidneys make these adjustments more slowly than the lungs do, this compensation generally takes several days.
Drinking plenty of water and drinking beverages containing electrolytes may NOT treat dehydration caused by which of the following?
A.
24-hour diarrhea
B.
Prolonged vomiting
C.
Profuse sweating
D.
Use of diuretic drugs
Answer: B: Prolonged vomiting. Doctors may treat the person with intravenous fluids containing sodium chloride. A, C, and D can usually be treated by drinking fluids and replacing electrolytes with special oral rehydration solutions.