DKA US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for DKA. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
DKA US Medical PG Question 1: A 27-year-old man with a past medical history of type I diabetes mellitus presents to the emergency department with altered mental status. The patient was noted as becoming more lethargic and confused over the past day, prompting his roommates to bring him in. His temperature is 99.0°F (37.2°C), blood pressure is 107/68 mmHg, pulse is 120/min, respirations are 17/min, and oxygen saturation is 98% on room air. Laboratory values are ordered as seen below.
Serum:
Na+: 144 mEq/L
Cl-: 100 mEq/L
K+: 6.3 mEq/L
HCO3-: 16 mEq/L
BUN: 20 mg/dL
Glucose: 599 mg/dL
Creatinine: 1.4 mg/dL
Ca2+: 10.2 mg/dL
Which of the following is the appropriate endpoint of treatment for this patient?
- A. Clinically asymptomatic
- B. Normal anion gap (Correct Answer)
- C. Normal glucose
- D. Vitals stable
- E. Normal potassium
DKA Explanation: ***Normal anion gap***
- A **normal anion gap** (approximately 8-12 mEq/L) indicates resolution of the **metabolic acidosis** characteristic of diabetic ketoacidosis (DKA). The current anion gap is high (Na - (Cl + HCO3) = 144 - (100 + 16) = 28 mEq/L).
- The patient's presentation with **type 1 diabetes** and **altered mental status**, coupled with **hyperglycemia** (599 mg/dL) and **low bicarbonate** (16 mEq/L), is highly suggestive of DKA, for which anion gap normalization is a key treatment endpoint.
*Clinically asymptomatic*
- While a desirable outcome, resolution of symptoms occurs gradually and is not the primary biochemical endpoint for DKA treatment.
- Patients may have residual symptoms even after metabolic derangements have significantly improved.
*Normal glucose*
- In DKA treatment, glucose is allowed to drop to a level (e.g., <200 mg/dL) but not necessarily to normal range, before initiating **dextrose-containing intravenous fluids** to prevent hypoglycemia while continuing insulin.
- **Normal glucose** alone does not guarantee resolution of ketoacidosis, which is the main life-threatening aspect of DKA.
*Vitals stable*
- **Stable vital signs** indicate hemodynamic stability, which is crucial but does not confirm the resolution of the underlying DKA metabolic derangements.
- Vitals can stabilize or worsen independently of acidosis resolution, especially if complications arise.
*Normal potassium*
- **Potassium levels** are critical to monitor and correct during DKA treatment, as insulin administration drives potassium into cells, potentially causing **hypokalemia**.
- While important for patient safety, achieving a normal potassium level is part of supportive care and not the primary endpoint for resolving the ketoacidotic state itself.
DKA US Medical PG Question 2: A 17-year-old male presents to your office complaining of polyuria, polydipsia, and unintentional weight loss of 12 pounds over the past 3 months. On physical examination, the patient is tachypneic with labored breathing. Which of the following electrolyte abnormalities would you most likely observe in this patient?
- A. Hypophosphatemia
- B. Hypermagnesemia
- C. Hyperkalemia
- D. Hyponatremia (Correct Answer)
- E. Hyperphosphatemia
DKA Explanation: ***Hyponatremia***
- This patient's symptoms of polyuria, polydipsia, and weight loss, along with **tachypnea and labored breathing**, are highly suggestive of **diabetic ketoacidosis (DKA)**.
- **Hyponatremia** is the **most consistently observed** electrolyte abnormality in DKA, present in nearly all cases at initial presentation.
- This is typically **pseudohyponatremia** caused by the osmotic effect of severe hyperglycemia—glucose pulls water into the extracellular space, diluting the measured sodium concentration.
- The **corrected sodium** can be calculated using: Corrected Na = Measured Na + 0.016 × (Glucose - 100), which typically reveals a more normal sodium level.
- True hyponatremia from sodium loss via **osmotic diuresis** can also occur but is usually masked by the dilutional effect.
*Hyperkalemia*
- While serum potassium may appear normal or even elevated initially due to **transcellular shifts** (acidosis causes potassium to move from intracellular to extracellular space in exchange for hydrogen ions), this is not the most consistently observed abnormality.
- **Total body potassium is always depleted** in DKA due to osmotic diuresis and vomiting.
- Many patients present with normal or even low potassium levels despite acidosis.
- Potassium levels require careful monitoring during treatment as insulin therapy drives potassium back into cells, potentially causing life-threatening hypokalemia.
*Hypophosphatemia*
- While **phosphate levels** can fluctuate in DKA due to osmotic diuresis, initial presentation often involves normal or even elevated phosphate levels due to cellular shifts.
- Significant **hypophosphatemia** is more typically observed during treatment as insulin drives phosphate back into the cells, similar to potassium.
*Hypermagnesemia*
- **Hypermagnesemia** is uncommon in DKA and is usually associated with impaired renal excretion or excessive magnesium intake.
- The symptoms described do not point towards magnesium imbalance.
*Hyperphosphatemia*
- Although cellular shifts can initially raise serum phosphate, sustained **hyperphosphatemia** is not a characteristic or common electrolyte abnormality seen in the acute presentation of DKA.
- More typically, total body phosphate is depleted due to **osmotic diuresis**.
DKA US Medical PG Question 3: A 22-year-old woman with a history of type I diabetes mellitus presents to the emergency department with nausea, vomiting, and drowsiness for the past day. Her temperature is 98.3°F (36.8°C), blood pressure is 114/74 mmHg, pulse is 120/min, respirations are 27/min, and oxygen saturation is 100% on room air. Physical exam is notable for a confused and lethargic young woman. Initial laboratory values are notable for the findings below.
Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 2.9 mEq/L
HCO3-: 9 mEq/L
BUN: 20 mg/dL
Glucose: 599 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.2 mg/dL
AST: 12 U/L
ALT: 10 U/L
An initial ECG is notable for sinus tachycardia. Which of the following is the best initial step in management for this patient?
- A. Normal saline and insulin
- B. Insulin and potassium
- C. Normal saline and potassium
- D. Normal saline, insulin, and potassium (Correct Answer)
- E. Normal saline, insulin, potassium, and sodium bicarbonate
DKA Explanation: ***Normal saline, insulin, and potassium***
- This patient presents with signs and symptoms consistent with **diabetic ketoacidosis (DKA)**, including hyperglycemia (glucose 599 mg/dL), metabolic acidosis (HCO3- 9 mEq/L, respiratory compensation with elevated respiratory rate), and altered mental status. The initial management of DKA involves aggressive **intravenous fluid resuscitation** (normal saline), **insulin administration** to correct hyperglycemia and acidosis, and **potassium replacement** due to total body potassium depletion and anticipated further drop with insulin therapy.
- Her **hypokalemia (2.9 mEq/L)**, even before insulin administration, necessitates immediate potassium repletion as insulin drives potassium intracellularly, which could worsen hypokalemia and lead to arrhythmias.
*Normal saline and insulin*
- While fluid resuscitation and insulin are crucial for DKA management, omitting **potassium replacement** in a patient with initial hypokalemia (K+ 2.9 mEq/L) would be inappropriate and potentially dangerous.
- Failure to correct hypokalemia before or with insulin administration can precipitate life-threatening **cardiac arrhythmias**.
*Normal saline, insulin, potassium, and sodium bicarbonate*
- **Sodium bicarbonate** is generally not recommended for DKA unless pH is extremely low (typically <6.9), as it can worsen cerebral edema and hypokalemia. The patient's bicarbonate of 9 mEq/L and presumably higher pH does not warrant bicarbonate administration.
- While fluids, insulin, and potassium are essential, the addition of sodium bicarbonate is usually reserved for severe, life-threatening acidosis (pH < 6.9).
*Normal saline and potassium*
- Administering only normal saline and potassium would address dehydration and hypokalemia but would fail to correct the underlying **hyperglycemia** and **ketoacidosis**, which are the core pathologies of DKA.
- **Insulin** is critical to stop ketogenesis and lower blood glucose.
*Insulin and potassium*
- Administering insulin and potassium without **fluid resuscitation** would be inadequate. The patient is likely significantly dehydrated due to osmotic diuresis from hyperglycemia and vomiting.
- **Fluid administration** is paramount in restoring circulating volume, improving renal perfusion, and reducing hyperglycemia by enhancing glucose excretion.
DKA US Medical PG Question 4: A 27-year-old man presents to the emergency department with his family because of abdominal pain, excessive urination, and drowsiness since the day before. He has had type 1 diabetes mellitus for 2 years. He ran out of insulin 2 days ago. The vital signs at admission include: temperature 36.8°C (98.2°F), blood pressure 102/69 mm Hg, and pulse 121/min. On physical examination, he is lethargic and his breathing is rapid and deep. There is a mild generalized abdominal tenderness without rebound tenderness or guarding. His serum glucose is 480 mg/dL. Arterial blood gas of this patient will most likely show which of the following?
- A. ↑ pH, ↑ bicarbonate, and normal pCO2
- B. ↓ pH, ↓ bicarbonate and ↑ anion gap (Correct Answer)
- C. ↑ pH, normal bicarbonate and ↓ pCO2
- D. ↓ pH, ↓ bicarbonate and normal anion gap
- E. ↓ pH, normal bicarbonate and ↑ pCO2
DKA Explanation: ***↓ pH, ↓ bicarbonate and ↑ anion gap***
- The patient's symptoms (abdominal pain, excessive urination, drowsiness, rapid and deep breathing, hyperglycemia) and history of Type 1 diabetes with missed insulin are highly suggestive of **diabetic ketoacidosis (DKA)**.
- DKA is characterized by **metabolic acidosis** due to the accumulation of ketone bodies, leading to a **decreased pH**, consumption of bicarbonate and thus a **decreased bicarbonate level**, and an **increased anion gap**.
*↑ pH, ↑ bicarbonate, and normal pCO2*
- This pattern suggests a **metabolic alkalosis**, which is inconsistent with the patient's presentation of DKA.
- Metabolic alkalosis is typically seen in conditions like severe vomiting or diuretic use, not uncontrolled diabetes.
*↑ pH, normal bicarbonate and ↓ pCO2*
- This profile describes **respiratory alkalosis**, often caused by primary hyperventilation.
- While the patient has rapid and deep breathing (Kussmaul respiration), this is a compensatory mechanism for metabolic acidosis, not a primary respiratory alkalosis.
*↓ pH, ↓ bicarbonate and normal anion gap*
- This indicates a **normal anion gap metabolic acidosis**, also known as hyperchloremic acidosis.
- This is typically seen in conditions like renal tubular acidosis or severe diarrhea, where bicarbonate is lost or chloride is retained, which is not the case for DKA.
*↓ pH, normal bicarbonate and ↑ pCO2*
- This presentation indicates **respiratory acidosis**, which is caused by hypoventilation and retention of CO2.
- The patient's rapid and deep breathing (Kussmaul breathing) is a compensatory mechanism to blow off CO2 and would decrease pCO2, not increase it.
DKA US Medical PG Question 5: A previously healthy 14-year-old girl is brought to the emergency department by her mother because of abdominal pain, nausea, and vomiting for 6 hours. Over the past 6 weeks, she has also had increased frequency of urination, and she has been drinking more water than usual. She has lost 6 kg (13 lb) over the same time period despite having a good appetite. Her temperature is 37.1°C (98.8°F), pulse is 125/min, respirations are 32/min, and blood pressure is 94/58 mm Hg. She appears lethargic. Physical examination shows deep and labored breathing and dry mucous membranes. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Urine dipstick is positive for ketones and glucose. Further evaluation is most likely to show which of the following findings?
- A. Excess water retention
- B. Serum glucose concentration > 800 mg/dL
- C. Increased arterial pCO2
- D. Increased arterial blood pH
- E. Decreased total body potassium (Correct Answer)
DKA Explanation: ***Decreased total body potassium***
- This is the correct answer. In **diabetic ketoacidosis (DKA)**, patients have **significant total body potassium depletion** due to osmotic diuresis and urinary losses.
- **Serum potassium may initially appear normal or even elevated** due to acidosis-induced extracellular shift of potassium from cells.
- However, **total body potassium stores are markedly depleted**, and during treatment with insulin and fluids, severe hypokalemia can develop as potassium shifts back intracellularly.
*Excess water retention*
- The patient's symptoms, including **polydipsia**, **polyuria**, and **dry mucous membranes**, indicate **dehydration**, not excessive water retention.
- Her blood pressure of 94/58 mm Hg also suggests **volume depletion**.
*Serum glucose concentration > 800 mg/dL*
- While the patient has significant hyperglycemia (indicated by glucose in urine), **DKA** typically presents with glucose levels between **250-600 mg/dL**.
- Glucose levels >800 mg/dL are more characteristic of **hyperosmolar hyperglycemic state (HHS)**, which is less common in children and usually lacks significant ketosis.
*Increased arterial pCO2*
- The patient exhibits **Kussmaul respirations** (deep and labored breathing) and an increased respiratory rate (32/min), which are compensatory mechanisms for **metabolic acidosis**.
- This compensation leads to **decreased arterial pCO2** as the body tries to blow off CO2 to raise pH.
*Increased arterial blood pH*
- The symptoms, particularly **Kussmaul respirations** and the presence of **ketones** in the urine, strongly suggest **diabetic ketoacidosis (DKA)**.
- DKA is characterized by **severe metabolic acidosis**, meaning the arterial blood pH would be **decreased**, not increased.
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