1. A lean 19-year-old presents with polyuria, weight loss, and a recent episode of diabetic ketoacidosis (DKA), and is diagnosed with type 1 diabetes mellitus. There is no measurable endogenous insulin secretion. Which insulin regimen most appropriately reflects the physiological replacement this patient requires?
A) A single morning dose of NPH (neutral protamine Hagedorn) insulin alone
B) A basal insulin analog once daily combined with a rapid-acting analog at each meal (basal-bolus), reproducing continuous between-meal suppression of hepatic glucose output plus mealtime coverage
C) A premixed 70/30 insulin once daily with no separate basal or bolus titration
D) Mealtime rapid-acting insulin only, with no basal component
E) An SGLT-2 (sodium-glucose cotransporter-2) inhibitor as monotherapy without insulin
ANSWER: B
Rationale:
Type 1 diabetes mellitus with absent endogenous secretion requires complete physiological replacement: a basal insulin to provide continuous suppression of hepatic glucose output between meals and overnight, plus a rapid-acting analog at each meal to cover postprandial excursions. A basal-bolus regimen accomplishes this and allows independent titration of each component, which is essential in a DKA-prone patient.
Option A: Option A is incorrect because once-daily NPH alone has a pronounced peak, does not provide flat basal coverage, and omits mealtime bolus insulin.
Option C: Option C is incorrect because a premixed formulation sacrifices the independent basal and bolus titration this patient needs.
Option D: Option D is incorrect because omitting basal insulin leaves hepatic glucose output unopposed overnight and risks recurrent ketoacidosis.
Option E: Option E is incorrect because insulin is mandatory in type 1 diabetes; an SGLT-2 inhibitor cannot replace it and carries ketoacidosis risk if used without insulin.
2. A patient with type 2 diabetes mellitus on bedtime NPH (neutral protamine Hagedorn) insulin has recurrent hypoglycemia at about 3 in the morning with otherwise acceptable daytime control. Which change is most appropriate to address the nocturnal hypoglycemia while maintaining basal coverage?
A) Increase the bedtime NPH dose to push glucose higher overnight
B) Move the NPH dose to the morning and add a second NPH dose at lunch
C) Discontinue all basal insulin and rely on mealtime bolus insulin only
D) Switch the bedtime NPH to a peakless long-acting basal analog such as glargine or degludec, eliminating the early-morning peak responsible for the nocturnal hypoglycemia
E) Add a rapid-acting analog at bedtime to smooth overnight glucose
ANSWER: D
Rationale:
NPH (neutral protamine Hagedorn) has a pronounced peak at roughly 4 to 8 hours, so a bedtime dose peaks in the early morning and is a recognized cause of nocturnal hypoglycemia. Switching to a peakless long-acting basal analog such as glargine or degludec provides flat basal coverage without the early-morning peak, directly addressing the problem.
Option A: Option A is incorrect because increasing the NPH dose intensifies the peak and worsens nocturnal hypoglycemia.
Option B: Option B is incorrect because adding daytime NPH does not remove the early-morning peak driving the nocturnal episodes.
Option C: Option C is incorrect because discontinuing basal insulin leaves hepatic glucose output unopposed overnight and is unsafe.
Option E: Option E is incorrect because adding a rapid-acting analog at bedtime would lower glucose further overnight and increase, not reduce, nocturnal hypoglycemia.
3. A patient with type 2 diabetes mellitus and severe insulin resistance requires more than 250 units of insulin per day. Glucose control is erratic, and the large injection volumes are causing inconsistent absorption. Which intervention best addresses this problem?
A) Switch to U-500 regular insulin, which at 500 units/mL reduces injection volume by about 80 percent and improves absorption consistency in patients requiring very large doses
B) Continue U-100 insulin but split each dose across many small injections at one site
C) Switch to a U-100 rapid-acting analog given once daily
D) Discontinue insulin and manage with diet alone
E) Add a second basal analog at the same total volume to spread the dose
ANSWER: A
Rationale:
Subcutaneous absorption becomes erratic when injected volumes exceed roughly 50 units per site, which is the problem in a patient needing more than 250 units per day. U-500 regular insulin contains 500 units/mL, a five-fold concentration that reduces injection volume by about 80 percent and improves absorption consistency, and its depot pharmacokinetics at high local concentration allow twice- or three-times-daily dosing.
Option B: Option B is incorrect because injecting many small volumes at a single site promotes lipohypertrophy and does not solve the underlying volume problem.
Option C: Option C is incorrect because a once-daily U-100 rapid-acting analog provides neither adequate basal coverage nor a reduced volume.
Option D: Option D is incorrect because diet alone cannot control a patient with this degree of insulin requirement.
Option E: Option E is incorrect because adding more insulin at the same concentration does not reduce per-injection volume and would worsen the absorption problem.
4. A critically ill patient in the intensive care unit (ICU) has persistent hyperglycemia and anticipated prolonged inability to eat. Based on the evidence from intensive-care glucose trials, which approach to glycemic management is most appropriate?
A) Subcutaneous glargine once daily with no glucose monitoring
B) Intermittent subcutaneous NPH every 6 hours targeting a glucose below 110 mg/dL
C) An intravenous regular insulin infusion titrated by a structured algorithm targeting a glucose of 140 to 180 mg/dL, the range supported by the NICE-SUGAR (Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation) trial
D) Intravenous insulin infusion targeting a glucose of 81 to 108 mg/dL for the tightest possible control
E) Oral agents alone, deferring insulin until the patient can eat
ANSWER: C
Rationale:
For a critically ill patient with sustained hyperglycemia and prolonged inability to eat, an intravenous regular insulin infusion titrated by a structured algorithm provides the most precise control, and the NICE-SUGAR (Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation) trial supports a target of 140 to 180 mg/dL.
Option A: Option A is incorrect because basal insulin without monitoring cannot provide the precise, responsive control a critically ill patient needs.
Option B: Option B is incorrect because intermittent subcutaneous NPH is not the standard ICU approach and a sub-110 target increases hypoglycemia risk.
Option D: Option D is incorrect because NICE-SUGAR demonstrated that intensive control targeting 81 to 108 mg/dL increased mortality compared with conventional control, largely from severe hypoglycemia.
Option E: Option E is incorrect because withholding insulin in a hyperglycemic critically ill patient is inappropriate and oral agents are unsuitable in this setting.
5. A patient with cirrhosis and type 2 diabetes mellitus on a stable insulin regimen develops increasingly frequent hypoglycemia as the liver disease progresses. Which management decision and rationale are most appropriate?
A) Increase the insulin dose, because cirrhosis raises insulin requirements through enhanced hepatic clearance
B) Make no change, because the liver has no role in insulin handling
C) Switch entirely to NPH (neutral protamine Hagedorn) insulin, because it is unaffected by hepatic disease
D) Add a sulfonylurea, because it is the safest agent in cirrhosis
E) Reduce the insulin dose, because cirrhosis reduces first-pass hepatic insulin extraction, increasing peripheral insulin exposure and predisposing to hypoglycemia
ANSWER: E
Rationale:
Cirrhosis reduces first-pass hepatic insulin extraction, so a larger fraction of each dose reaches the peripheral circulation, increasing insulin exposure and predisposing to hypoglycemia; cirrhotic patients therefore often require reduced insulin doses despite peripheral insulin resistance.
Option A: Option A is incorrect because cirrhosis decreases hepatic insulin extraction and clearance, so requirements typically fall rather than rise.
Option B: Option B is incorrect because the liver is a major site of insulin handling, so progressive liver disease directly affects insulin exposure.
Option C: Option C is incorrect because NPH is not protected from the effects of hepatic dysfunction, and switching insulin type does not address the reduced clearance.
Option D: Option D is incorrect because sulfonylureas carry hypoglycemia risk and are not a safe substitute in cirrhosis, particularly in a patient already prone to hypoglycemia.
6. A kidney transplant recipient maintained on tacrolimus develops new hyperglycemia, and the insulin doses needed to control it are steadily climbing. Which explanation best accounts for the rising insulin requirements?
A) Tacrolimus lowers insulin requirements by improving beta cell function
B) Tacrolimus, a calcineurin inhibitor, is directly toxic to pancreatic beta cells and promotes insulin resistance, raising insulin requirements, so anticipatory dose increases and glucose monitoring are warranted
C) Tacrolimus has no effect on glucose metabolism, so the hyperglycemia must be unrelated to the drug
D) Tacrolimus increases endogenous insulin secretion, which paradoxically lowers glucose
E) The hyperglycemia reflects accelerated insulin clearance caused by tacrolimus
ANSWER: B
Rationale:
Tacrolimus is a calcineurin inhibitor that is directly toxic to pancreatic beta cells and promotes insulin resistance (an effect generally greater than with cyclosporine), predictably raising insulin requirements; anticipatory dose increases with close glucose monitoring are appropriate.
Option A: Option A is incorrect because tacrolimus impairs rather than improves beta cell function.
Option C: Option C is incorrect because calcineurin inhibitors are a well-recognized cause of post-transplant hyperglycemia, so the drug is directly relevant.
Option D: Option D is incorrect because tacrolimus reduces, not increases, insulin secretion.
Option E: Option E is incorrect because the rising requirement reflects beta-cell toxicity and insulin resistance, not accelerated insulin clearance.
7. A healthcare worker without diabetes is brought in with recurrent unexplained hypoglycemia. During an episode, laboratory testing shows a high plasma insulin level with a suppressed (low) C-peptide. What is the most likely explanation?
A) Surreptitious administration of exogenous insulin, because exogenous insulin raises measured insulin while C-peptide, which is co-secreted only with endogenous insulin, is suppressed
B) An insulinoma, because tumor hypersecretion raises both insulin and C-peptide
C) A sulfonylurea overdose, because sulfonylureas raise insulin and C-peptide together
D) Renal failure causing reduced insulin clearance, because this elevates both insulin and C-peptide
E) Normal physiology, because high insulin with low C-peptide is the expected fasting pattern
ANSWER: A
Rationale:
C-peptide is co-secreted in equimolar amounts with endogenous insulin but is absent from all commercial insulin preparations. A high measured insulin level with a suppressed C-peptide therefore indicates an exogenous insulin source, consistent with surreptitious (factitious) insulin administration, and the healthcare occupation increases access.
Option B: Option B is incorrect because an insulinoma raises endogenous secretion, elevating both insulin and C-peptide.
Option C: Option C is incorrect because sulfonylureas stimulate endogenous secretion, also raising C-peptide along with insulin.
Option D: Option D is incorrect because reduced renal clearance would not selectively suppress C-peptide relative to insulin in this discriminating pattern.
Option E: Option E is incorrect because high insulin with suppressed C-peptide is not a normal fasting pattern; fasting normally lowers insulin.
8. A patient with type 1 diabetes mellitus plans a long afternoon run and has had hypoglycemia during previous workouts. Which preemptive strategy best reduces the exercise-related hypoglycemia risk?
A) Inject the pre-exercise bolus into the leg that will be exercised to speed its action
B) Increase the pre-exercise mealtime bolus to cover anticipated activity
C) Reduce the pre-exercise mealtime bolus and avoid injecting into the limb that will be exercised, because exercise increases insulin-independent glucose uptake and exercising the injected limb accelerates insulin absorption, both of which lower glucose
D) Apply heat to the injection site before running to stabilize absorption
E) Skip basal insulin on exercise days to prevent any hypoglycemia
ANSWER: C
Rationale:
Exercise lowers glucose by increasing insulin-independent (AMPK-mediated) GLUT4 (glucose transporter type 4) translocation, and exercising a limb into which insulin was injected accelerates absorption by raising local blood flow; both effects compound the risk of hypoglycemia. Reducing the pre-exercise mealtime bolus and choosing an injection site away from the exercised limb directly mitigates these mechanisms.
Option A: Option A is incorrect because injecting into the limb to be exercised speeds absorption and increases hypoglycemia risk.
Option B: Option B is incorrect because increasing the bolus before exercise would deepen the glucose fall.
Option D: Option D is incorrect because heat raises local blood flow and accelerates absorption, worsening rather than stabilizing the situation.
Option E: Option E is incorrect because omitting basal insulin in type 1 diabetes risks ketoacidosis and is not appropriate management.
9. A pregnant patient with type 1 diabetes mellitus required nearly double her pre-pregnancy insulin dose by the third trimester. She is about to deliver. What insulin adjustment should the team anticipate at the time of delivery, and why?
A) Continue the third-trimester doses unchanged for several weeks postpartum
B) Increase the insulin dose further immediately after delivery to match peak resistance
C) Taper the dose slowly over the next two to three months with no acute change
D) Reduce the insulin dose sharply right after delivery, because removal of the placenta abruptly eliminates the placental hormones driving insulin resistance, causing requirements to fall steeply and creating hypoglycemia risk if the high dose is continued
E) Stop all insulin permanently because pregnancy resolves type 1 diabetes
ANSWER: D
Rationale:
Placental hormones (human placental lactogen, cortisol, progesterone, prolactin) drive progressive insulin resistance, often roughly doubling the insulin requirement by the third trimester. Delivery of the placenta abruptly removes these hormones, so insulin requirements fall steeply within hours; continuing the high third-trimester dose would cause hypoglycemia, and the dose must be reduced sharply right after delivery.
Option A: Option A is incorrect because requirements drop immediately at delivery rather than persisting for weeks.
Option B: Option B is incorrect because resistance falls, not rises, once the placenta is delivered.
Option C: Option C is incorrect because the change is abrupt at delivery, not a gradual months-long taper.
Option E: Option E is incorrect because type 1 diabetes persists after pregnancy and insulin remains required.
10. An insulin-treated patient is brought to the emergency department unconscious with a fingerstick glucose of 28 mg/dL. Intravenous access is already established. Which treatment is the most appropriate definitive therapy in this in-hospital setting?
A) Oral glucose gel placed in the cheek of the unconscious patient
B) Withhold treatment and recheck glucose in 30 minutes
C) Intramuscular glucagon as the definitive in-hospital treatment
D) A rapid-acting insulin correction to stabilize glucose
E) Intravenous dextrose (for example, 25 to 50 mL of 50% dextrose, D50W), the definitive in-hospital treatment for severe hypoglycemia when intravenous access is available
ANSWER: E
Rationale:
For severe hypoglycemia in a patient who cannot safely take oral glucose, intravenous dextrose (for example, 25 to 50 mL of 50% dextrose, D50W) is the definitive in-hospital treatment and acts rapidly; with intravenous access already in place it is preferred over glucagon.
Option A: Option A is incorrect and unsafe because giving oral glucose to an unconscious patient risks aspiration.
Option B: Option B is incorrect because severe hypoglycemia requires immediate treatment, not delayed rechecking.
Option C: Option C is incorrect because, although glucagon is the standard out-of-hospital option, intravenous dextrose is the definitive choice when access is available, and glucagon depends on adequate hepatic glycogen.
Option D: Option D is incorrect and dangerous because giving insulin would lower glucose further.
11. A patient with type 2 diabetes mellitus on insulin is started on olanzapine for a psychiatric indication. Over the following months he gains substantial weight, and his insulin requirements rise steadily with worsening glycemic control. Which explanation and management consideration are most appropriate?
A) Olanzapine improves insulin sensitivity, so the rising requirements must reflect nonadherence alone
B) Olanzapine, an atypical antipsychotic, promotes weight gain and insulin resistance, which raises insulin requirements; management includes intensified glucose monitoring, anticipatory insulin adjustment, coordination with psychiatry about the antipsychotic choice, and weight-mitigating strategies
C) Olanzapine has no metabolic effects, so the weight gain and hyperglycemia are coincidental
D) Olanzapine accelerates insulin clearance, which is why more insulin is needed
E) The weight gain is purely from insulin, and the olanzapine is metabolically neutral
ANSWER: B
Rationale:
Atypical antipsychotics such as olanzapine (and clozapine) are well recognized to promote weight gain and insulin resistance, predictably raising insulin requirements and worsening glycemic control. Appropriate management includes intensified glucose monitoring, anticipatory insulin adjustment, coordination with psychiatry regarding the choice of antipsychotic, and weight-mitigating strategies.
Option A: Option A is incorrect because olanzapine worsens, not improves, insulin sensitivity.
Option C: Option C is incorrect because olanzapine has well-documented metabolic effects, so the findings are not coincidental.
Option D: Option D is incorrect because the rising requirement reflects insulin resistance and weight gain, not accelerated insulin clearance.
Option E: Option E is incorrect because olanzapine is not metabolically neutral; it is a major contributor to the weight gain and insulin resistance.
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