Glucose Tolerance Tests Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Glucose Tolerance Tests. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Glucose Tolerance Tests Indian Medical PG Question 1: In Type 1 Diabetes Mellitus (DM) stage 3 beta cell destruction, which of the following is the most likely presentation?
- A. Dysglycemic symptomatic
- B. Normoglycemic symptomatic
- C. Dysglycemic asymptomatic
- D. Hyperglycemia symptomatic (Correct Answer)
- E. Normoglycemic asymptomatic
Glucose Tolerance Tests Explanation: ***Hyperglycemia symptomatic***
- **Type 1 DM stage 3** is characterized by sufficient **beta-cell destruction** to cause overt hyperglycemia.
- This level of hyperglycemia typically leads to classic symptoms such as **polyuria, polydipsia, and weight loss**.
*Dysglycemic symptomatic*
- **Dysglycemic** refers to abnormal blood sugar levels, but this term is too broad and doesn't specify the degree or symptomatic nature as precisely as **hyperglycemia symptomatic**.
- While patients are symptomatic, the primary issue is **hyperglycemia**, making that a more specific and accurate description.
*Normoglycemic symptomatic*
- **Normoglycemic** implies normal blood sugar levels, which is inconsistent with **Type 1 DM stage 3** where significant beta-cell destruction has occurred.
- This stage is defined by definite hyperglycemia, so a patient cannot be symptomatic while having normal glucose levels due to the disease.
*Dysglycemic asymptomatic*
- While there is **dysglycemia**, **asymptomatic presentation** is more characteristic of earlier stages (Type 1 DM stage 2), where hyperglycemia is present but not yet severe enough to cause overt symptoms.
- In **stage 3**, beta-cell destruction is substantial, leading to glucose levels that are high enough to cause noticeable symptoms.
*Normoglycemic asymptomatic*
- **Normoglycemic asymptomatic** describes **Type 1 DM stage 1**, where autoimmunity is present but beta-cell destruction has not yet progressed enough to affect glucose levels.
- This is the earliest stage of Type 1 DM, well before the overt hyperglycemia seen in stage 3.
Glucose Tolerance Tests Indian Medical PG Question 2: Which assay is primarily used to assess growth hormone levels?
- A. Diabetes mellitus
- B. Glucagon assay
- C. Growth hormone stimulation test (Correct Answer)
- D. Catecholamines
Glucose Tolerance Tests Explanation: ***Growth hormone stimulation test***
- This is the primary diagnostic assay to evaluate **growth hormone (GH) deficiency** or excess, as GH levels fluctuate throughout the day.
- Various stimuli, such as **insulin-induced hypoglycemia**, **arginine**, or **clonidine**, are used to trigger GH release, and levels are measured serially [1].
*Diabetes mellitus*
- This is a metabolic disorder characterized by **elevated blood glucose levels** due to insulin deficiency or resistance, not an assay for growth hormone.
- While growth hormone can affect glucose metabolism, diabetes mellitus describes a **disease state**, not a diagnostic test for growth hormone levels [2].
*Glucagon assay*
- A glucagon assay measures the level of **glucagon**, a hormone produced by the pancreas that raises blood glucose levels.
- While glucagon can be used in some stimulation tests for growth hormone, a "glucagon assay" alone is not the primary method to assess overall growth hormone status.
*Catecholamines*
- Catecholamines are a group of hormones, including **epinephrine (adrenaline)**, **norepinephrine**, and **dopamine**, which are involved in the body's stress response.
- Assays for catecholamines are used to diagnose conditions like **pheochromocytoma** or neuroblastoma, not to assess growth hormone levels.
Glucose Tolerance Tests Indian Medical PG Question 3: Stress hyperglycemia occurs due to all except -
- A. Increased level of ACTH
- B. Decreased level of norepinephrine (Correct Answer)
- C. Insulin resistance
- D. Increased level of cortisol
Glucose Tolerance Tests Explanation: ***Decreased level of norepinephrine***
- **Norepinephrine** is a **catecholamine** that generally **increases blood glucose** by stimulating **glycogenolysis** and **gluconeogenesis**.
- Therefore, a *decrease* in norepinephrine would *reduce* stress-induced hyperglycemia, making this the exception.
*Increased level of ACTH*
- **ACTH (Adrenocorticotropic Hormone)** stimulates the adrenal glands to release **cortisol**, which contributes significantly to stress hyperglycemia.
- Increased ACTH levels therefore *promote* hyperglycemia in stress.
*Insulin resistance*
- **Insulin resistance** is a common feature during stress, where target cells become less responsive to insulin's effects.
- This reduced insulin sensitivity leads to higher circulating glucose levels, contributing to hyperglycemia.
*Increased level of cortisol*
- **Cortisol** is a key **stress hormone** that promotes **gluconeogenesis** (production of glucose from non-carbohydrate sources) and **glycogenolysis** (breakdown of glycogen to glucose).
- Elevated cortisol levels directly lead to an increase in blood glucose, causing hyperglycemia.
Glucose Tolerance Tests Indian Medical PG Question 4: The diagnosis of diabetes mellitus is certain in which of the following situations?
- A. Abnormal oral glucose tolerance in a 24-yrs-old woman who has been dieting
- B. A serum glucose level >7.8 mmol/L in a woman in her twenty-fifth week of gestation after a 50-g oral glucose load
- C. Persistent asymptomatic glycosuria in a 30-yrs-old woman
- D. Successive fasting plasma glucose concentrations of 8, 9, and 8.5 mmol/L in an asymptomatic, otherwise healthy individual. (Correct Answer)
Glucose Tolerance Tests Explanation: ***Successive fasting plasma glucose concentrations of 8, 9, and 8.5 mmol/L in an asymptomatic, otherwise healthy individual.***
- A definitive diagnosis of **diabetes mellitus** requires two separate fasting plasma glucose (FPG) levels of **≥7.0 mmol/L** (126 mg/dL) or higher [1]. The given values (8, 9, 8.5 mmol/L) meet this criterion.
- Since the individual is **asymptomatic**, two abnormal tests are typically needed to confirm the diagnosis, which is satisfied by the successive elevated fasting glucose levels.
*Abnormal oral glucose tolerance in a 24-yrs-old woman who has been dieting*
- **Dieting** can affect glucose metabolism and potentially lead to an abnormal oral glucose tolerance test (OGTT) result that does not accurately reflect diabetes.
- A single abnormal OGTT in a dieting individual without confirmatory tests or symptoms is not sufficient for a definitive diagnosis of diabetes.
*A serum glucose level >7.8 mmol/L in a woman in her twenty-fifth week of gestation after a 50-g oral glucose load*
- A serum glucose level >7.8 mmol/L after a **50-g glucose challenge** is a positive screening test for **gestational diabetes mellitus**, but it is not diagnostic [2].
- A positive screening test requires further confirmation with a **100-g or 75-g oral glucose tolerance test** to diagnose gestational diabetes.
*Persistent asymptomatic glycosuria in a 30-yrs-old woman*
- **Glycosuria** (glucose in the urine) without hyperglycemia (elevated blood glucose) can be due to a low **renal threshold for glucose**, a benign condition called renal glycosuria.
- While it warrants investigation for diabetes, persistent asymptomatic glycosuria alone is **not diagnostic** of diabetes unless accompanied by elevated blood glucose levels.
Glucose Tolerance Tests Indian Medical PG Question 5: In infants of diabetic mothers (IDM), when is ophthalmologic evaluation indicated?
- A. At the time of diagnosis
- B. Only if visual symptoms develop (Correct Answer)
- C. After 5 years routinely
- D. After developing diabetes
Glucose Tolerance Tests Explanation: ***Only if visual symptoms develop***
- Unlike **retinopathy of prematurity**, infants of diabetic mothers (IDMs) do not have a higher incidence of **retinopathy** or other **ocular abnormalities** at birth or in early infancy.
- **Ophthalmologic evaluation** is generally reserved for IDMs who develop specific **visual symptoms** or signs of ocular pathology.
*At the time of diagnosis*
- Routine ophthalmologic screening at the time of diagnosis of IDM is **not standard practice**, as the risk of **congenital ocular anomalies** is not substantially elevated to warrant universal screening.
- Initial management focuses on metabolic stability, especially **glucose control**, and screening for other common IDM-related complications like **cardiac defects** or **respiratory distress**.
*After 5 years routinely*
- There is **no evidence or recommendation** for routine ophthalmologic screening of IDMs specifically at the age of 5 years.
- Regular **well-child check-ups** include basic vision screening, which would identify significant refractive errors or strabismus, but not specifically for diabetes-related ocular issues.
*After developing diabetes*
- While it is true that individuals with **type 1 or type 2 diabetes** require regular **ophthalmologic evaluations** for **diabetic retinopathy**, this refers to the child developing diabetes later in life, not being an IDM.
- Being an IDM is a **risk factor for developing diabetes** later in life, but it doesn't automatically mean they have diabetes-related ocular issues from birth.
Glucose Tolerance Tests Indian Medical PG Question 6: Low osmolarity ORS - false statement is
- A. Sodium concentration 75 mmol/liter
- B. Osmolarity is 311 mosm/liter (Correct Answer)
- C. Potassium is 20 mmol/liter
- D. Glucose concentration 75 mmol/liter
Glucose Tolerance Tests Explanation: ***Osmolarity is 311 mosm/liter***
- Low osmolarity ORS has an osmolarity of **245 mOsm/L**, calculated as: **Sodium 75 + Potassium 20 + Chloride 65 + Glucose 75 + Citrate 10 = 245 mOsm/L**.
- An osmolarity of **311 mOsm/L** corresponds to the **standard WHO ORS**, not the low osmolarity ORS which was developed to reduce osmotic load.
*Sodium concentration 75 mmol/liter*
- This statement is **true** for low osmolarity ORS, as its sodium concentration is indeed **75 mmol/L**.
- The reduced sodium concentration (compared to **90 mmol/L** in standard ORS) helps achieve the lower overall osmolarity.
*Potassium is 20 mmol/liter*
- This statement is **true** for low osmolarity ORS, as it contains **20 mmol/L of potassium**.
- Potassium is crucial for replacing **electrolyte losses** in diarrhea and maintaining intracellular fluid balance.
*Glucose concentration 75 mmol/liter*
- This statement is also **true** for low osmolarity ORS, with a glucose concentration of **75 mmol/L (13.5 g/L)**.
- The glucose promotes **sodium-glucose co-transport** in the intestine, facilitating water absorption despite lower sodium concentration.
Glucose Tolerance Tests Indian Medical PG Question 7: Hyperglycemia occurs after what % of beta cell mass is destroyed:
- A. 40%
- B. 80% (Correct Answer)
- C. 60%
- D. 20%
Glucose Tolerance Tests Explanation: ***80%***
- **Hyperglycemia** typically manifests only after a significant portion of **beta cell mass** (around 80-90%) has been destroyed.
- This extensive loss of **insulin-producing cells** compromises the body's ability to maintain normal glucose levels [1].
*20%*
- A 20% destruction of beta cell mass is generally **insufficient** to cause clinical hyperglycemia.
- The remaining beta cells can usually compensate for this relatively small loss through increased insulin secretion.
*40%*
- While 40% loss represents a considerable reduction, it's often still within the compensatory capacity of the pancreas.
- At this stage, individuals might experience **impaired glucose tolerance** but not overt hyperglycemia [1].
*60%*
- Even with a 60% loss, the body may still be able to maintain near-normal glucose levels, especially in the early stages of beta cell destruction [1].
- Hyperglycemia is more likely to develop as the destruction progresses beyond this point.
Glucose Tolerance Tests Indian Medical PG Question 8: TRH stimulation testing is useful in diagnosis of disorders of the following hormones?
- A. PTH
- B. ACTH
- C. Insulin
- D. Growth hormone (Correct Answer)
Glucose Tolerance Tests Explanation: ***Growth hormone***
- **TRH** (Thyrotropin-Releasing Hormone) normally stimulates the release of **TSH** and **prolactin** from the anterior pituitary, but **does not normally affect growth hormone**.
- In certain pathological conditions like **acromegaly**, TRH can **paradoxically stimulate growth hormone release**, where GH levels abnormally increase instead of remaining unchanged.
- This **paradoxical GH response to TRH** is used as a diagnostic test in suspected acromegaly patients, helping differentiate it from normal physiology.
- Note: The primary uses of TRH stimulation are for assessing **TSH** (thyroid axis disorders) and **prolactin** (hyperprolactinemia), but among the given options, growth hormone is the relevant answer.
*PTH*
- **PTH** (Parathyroid Hormone) regulation is primarily controlled by **serum calcium levels**, not by TRH.
- Disorders of PTH are diagnosed through **calcium, phosphate, and PTH measurements**, not TRH stimulation.
*ACTH*
- **ACTH** (Adrenocorticotropic Hormone) release is stimulated by **CRH** (Corticotropin-Releasing Hormone), not TRH.
- Conditions involving ACTH are typically evaluated using **CRH stimulation tests** or **dexamethasone suppression tests**.
*Insulin*
- **Insulin** secretion by pancreatic beta cells is primarily regulated by **blood glucose levels**, not by TRH.
- Insulin-related disorders are diagnosed through **glucose tolerance tests**, **C-peptide levels**, and **insulin measurements**.
Glucose Tolerance Tests Indian Medical PG Question 9: The "cutoff" value of plasma glucose in a 50-g glucose challenge test is
- A. 120 mg/dL
- B. 140 mg/dL (Correct Answer)
- C. 160 mg/dL
- D. 180 mg/dL
Glucose Tolerance Tests Explanation: ***140 mg/dL***
- A plasma glucose level of **140 mg/dL** (7.8 mmol/L) or higher one hour after a **50-g glucose challenge** is considered abnormal and warrants further investigation with a 3-hour oral glucose tolerance test (OGTT).
- This cutoff helps identify individuals at risk for **gestational diabetes mellitus (GDM)**.
*120 mg/dL*
- This value is below the established cutoff for an abnormal 50-g glucose challenge test.
- A plasma glucose level of 120 mg/dL one hour after glucose intake is generally considered within the **normal range** for this screening test.
*160 mg/dL*
- While 160 mg/dL is an elevated value, the standard cutoff used to indicate a positive screen is 140 mg/dL.
- Using a higher cutoff like 160 mg/dL would **decrease the sensitivity** of the screening test, potentially missing cases of gestational diabetes.
*180 mg/dL*
- A plasma glucose level of 180 mg/dL is significantly elevated and would certainly lead to further testing.
- However, the American College of Obstetricians and Gynecologists (ACOG) and other major organizations recommend the **140 mg/dL cutoff** for initial screening to maximize sensitivity.
Glucose Tolerance Tests Indian Medical PG Question 10: Which test produces characteristic crystals for the detection of semen?
- A. Acid phosphatase test
- B. Florence test
- C. Barberio's test (Correct Answer)
- D. PSA test
Glucose Tolerance Tests Explanation: ***Barberio's test***
- This test is specifically used for the **microscopic detection of seminal fluid** by producing **characteristic spermine picrate crystals**.
- It involves the addition of a **saturated picric acid solution** to a semen stain extract, leading to the formation of distinct **yellow, needle-like crystals** that are diagnostic.
- It is a **confirmatory microscopic crystal test** that provides visual evidence of semen presence.
*Acid phosphatase test*
- This is a **presumptive test for semen** that relies on the detection of high levels of acid phosphatase, an enzyme found in seminal fluid.
- While it indicates the *possible* presence of semen, it is **not confirmatory** as acid phosphatase can be found in other bodily fluids and vegetable matter.
- Does **not produce crystals** for identification.
*Florence test*
- The Florence test is a **presumptive crystal test** that detects choline in semen, forming dark brown, rhombic crystals of choline periodide.
- However, it is **not specific for semen** because choline can be found in other biological materials and vaginal secretions.
- Less reliable than Barberio's test for semen confirmation.
*PSA test*
- The **prostate-specific antigen (PSA) test** is a highly specific **immunological confirmatory test** for human semen.
- It detects the glycoprotein PSA (P30) produced by the prostate gland.
- However, it does **not produce crystals** and uses different methodology (immunochromatography/ELISA).
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