Diabetes Mellitus — MCQs
A 45-year-old diabetic presents with sudden painless vision loss. Cotton wool spots and dot hemorrhages seen. HbA1c is 9.2. Most likely diagnosis?
What is a characteristic fundoscopic finding in advanced hypertensive retinopathy?
Which of the following ocular findings is not associated with diabetes?
Which of the following treatments is not suitable for advanced proliferative diabetic retinopathy with extensive vitreoretinal fibrosis and tractional retinal detachment?
What can be prevented by inhibiting aldose reductase in diabetes mellitus?
Vision 2020 includes all of the following, except?
Constantly changing refractive error is seen in:
A diabetic patient presents to you with visual acuity of 6/9 in one eye. Further investigations revealed preretinal hemorrhages with neovascularization at the optic disc. What is the next step in management?
The most common cause of early spontaneous abortion is:
In the management of diabetes mellitus, lactic acidosis is caused by which of the following?
Diabetes Mellitus Indian Medical PG Practice Questions and MCQs
Question 1: A 45-year-old diabetic presents with sudden painless vision loss. Cotton wool spots and dot hemorrhages seen. HbA1c is 9.2. Most likely diagnosis?
- A. Hypertensive retinopathy
- B. CRAO
- C. Diabetic retinopathy (Correct Answer)
- D. CRVO
Explanation: ***Diabetic retinopathy*** - The presence of **cotton wool spots** and **dot hemorrhages** in a diabetic patient with poor glycemic control (HbA1c 9.2) are classic signs of **diabetic retinopathy**. - **Painless vision loss** is a common presentation, especially with macular edema or proliferative disease. *Hypertensive retinopathy* - While cotton wool spots can be seen, **dot hemorrhages are less characteristic** than flame-shaped hemorrhages. - The primary driver here is **diabetes** and poor glycemic control, not necessarily hypertension as the main cause. *CRAO* - **Central retinal artery occlusion** typically presents with **sudden, profound, painless monocular vision loss**. - Funduscopic examination would reveal a **cherry-red spot** and **pale retina**, not cotton wool spots and dot hemorrhages. *CRVO* - **Central retinal vein occlusion** is characterized by **extensive retinal hemorrhages** (often described as "blood and thunder" appearance), tortuous veins, and optic disc edema. - While it can cause painless vision loss and some hemorrhages, the specific combination of **cotton wool spots and dot hemorrhages** in a diabetic context points more strongly to diabetic retinopathy.
Question 2: What is a characteristic fundoscopic finding in advanced hypertensive retinopathy?
- A. Cotton wool spots (Correct Answer)
- B. Microaneurysms
- C. Cherry-red spot
- D. Drusen
Explanation: ***Cotton wool spots*** - These are **soft exudates** that represent **acute focal infarction of the retinal nerve fiber layer** due to severe hypertension, indicating advanced hypertensive retinopathy (Grade III-IV). - They appear as **fluffy, white patches** with irregular, feathery borders in the superficial retina, caused by **ischemia and disruption of axoplasmic flow**. - In Grade IV (malignant hypertension), **optic disc edema** may also be present alongside cotton wool spots. *Microaneurysms* - These are small, dot-like hemorrhages common in **diabetic retinopathy**, resulting from weakened capillary walls. - While hypertension can coexist with diabetes and exacerbate retinal changes, **microaneurysms** are not a primary, characteristic finding of hypertensive retinopathy itself. *Cherry-red spot* - A **cherry-red spot** is a classic finding in **central retinal artery occlusion (CRAO)** and **Tay-Sachs disease**, due to the transparent fovea allowing visualization of the underlying choroidal circulation. - It does not characterize hypertensive retinopathy. *Drusen* - **Drusen** are yellow deposits under the retina, primarily associated with **age-related macular degeneration (AMD)**. - They are not a feature of hypertensive retinopathy.
Question 3: Which of the following ocular findings is not associated with diabetes?
- A. Retinopathy
- B. Early senile cataract
- C. Neovascular glaucoma
- D. Blepharophimosis (Correct Answer)
Explanation: ***Blepharophimosis*** - This is a **congenital disorder** characterized by small palpebral fissures, ptosis, and epicanthus inversus, which is **not associated with diabetes**. - It is a **developmental anomaly** of the eyelids, with no known link to metabolic conditions like diabetes. *Retinopathy* - **Diabetic retinopathy** is a common and serious complication of diabetes, caused by damage to the blood vessels in the retina. - It can lead to vision loss if not managed, and is directly linked to **poor glycemic control**. *Early senile cataract* - Diabetes is a significant risk factor for the **earlier development and progression of cataracts**, including senile cataracts. - High blood sugar levels can cause changes in the lens, leading to **opacification** and impaired vision. *Neovascular glaucoma* - This severe form of **secondary glaucoma** is often a complication of advanced **diabetic retinopathy**. - Ischemia in the retina triggers the growth of **new blood vessels** on the iris and in the angle of the eye, obstructing aqueous outflow and raising intraocular pressure.
Question 4: Which of the following treatments is not suitable for advanced proliferative diabetic retinopathy with extensive vitreoretinal fibrosis and tractional retinal detachment?
- A. Removal of epiretinal membrane
- B. Photocoagulation (Correct Answer)
- C. Vitrectomy
- D. Reattachment of detached or torn retina
Explanation: ***Photocoagulation*** - The question asks for a treatment **not suitable** for **advanced proliferative diabetic retinopathy** with **extensive vitreoretinal fibrosis** and **tractional retinal detachment (TRD)**. - **Panretinal photocoagulation (PRP)** is a laser treatment used to ablate ischemic peripheral retina and prevent neovascularization in proliferative diabetic retinopathy. However, it is a **preventive measure** used in **earlier stages of PDR** before the development of extensive fibrosis and tractional detachment. - Once **tractional retinal detachment** has developed with **extensive vitreoretinal fibrosis**, photocoagulation alone **cannot relieve the mechanical traction** on the retina or **reattach the detached retina**. At this advanced stage, **surgical intervention is required**. - While endolaser photocoagulation can be performed **during vitrectomy** as an adjunctive measure, standalone photocoagulation is not suitable as a primary treatment for established TRD with extensive fibrosis. *Vitrectomy* - **Pars plana vitrectomy** is the **definitive surgical treatment** for advanced PDR with tractional retinal detachment and extensive vitreoretinal fibrosis. - The procedure involves removal of the vitreous gel, fibrovascular membranes, and blood, which relieves traction on the retina and allows for retinal reattachment. - This is the **gold standard treatment** for this condition. *Removal of epiretinal membrane* - **Membrane peeling** (removal of epiretinal and fibrovascular membranes) is an **essential component** of vitrectomy for tractional retinal detachment. - Removing these membranes relieves the mechanical traction causing the retinal detachment, making this a **suitable and necessary** treatment step. - This is performed as part of the comprehensive vitrectomy procedure. *Reattachment of detached or torn retina* - **Retinal reattachment** is the primary **therapeutic goal** for tractional retinal detachment in advanced PDR. - This is achieved through vitrectomy with membrane peeling, often combined with endolaser, fluid-gas exchange, or silicone oil tamponade. - This is clearly a **suitable treatment objective** for this condition.
Question 5: What can be prevented by inhibiting aldose reductase in diabetes mellitus?
- A. Diabetic nephropathy
- B. Diabetic cataract (Correct Answer)
- C. Deafness
- D. Diabetic neuropathy
Explanation: ***Diabetic cataract*** - **Aldose reductase** is the key enzyme in the **polyol pathway**, which converts glucose to **sorbitol**. - In diabetes, high glucose levels lead to excessive sorbitol accumulation in the **lens**, causing **osmotic stress** and contributing to cataract formation. - **Aldose reductase inhibitors are most effective** in preventing diabetic cataracts, as the lens has limited sorbitol metabolism capacity. *Deafness* - While diabetes can affect **hearing**, the primary mechanism is often related to **microvascular damage** rather than the direct action of aldose reductase. - Aldose reductase inhibition is not a primary strategy for preventing diabetic hearing loss. *Diabetic nephropathy* - This kidney complication of diabetes is primarily caused by **glomerular hypertrophy**, **basement membrane thickening**, and **mesangial expansion**. - While the polyol pathway might play a minor role, it's not the main driver of nephropathy, and aldose reductase inhibitors have not shown significant benefit in preventing it clinically. *Diabetic neuropathy* - The **polyol pathway does contribute** to diabetic neuropathy through sorbitol accumulation in peripheral nerves, causing osmotic stress and **myoinositol depletion**. - However, neuropathy is **multifactorial**, involving **microvascular ischemia**, **oxidative stress**, and **advanced glycation end products (AGEs)**. - While aldose reductase inhibitors have shown **some benefit** for neuropathy, they have had **limited clinical success** compared to their effectiveness in preventing cataracts, making diabetic cataract the **best answer** to this question.
Question 6: Vision 2020 includes all of the following, except?
- A. Diabetic Retinopathy
- B. Refractive Errors
- C. Cataract
- D. Age-related Macular Degeneration (Correct Answer)
Explanation: ***Age-related Macular Degeneration*** - **Age-related macular degeneration (AMD)** was originally **not included** as one of the priority diseases in the initial "Vision 2020: The Right to Sight" initiative. - The initial focus was on conditions with a high burden of preventable blindness that were readily treatable or preventable with widely available interventions. *Diabetic Retinopathy* - **Diabetic retinopathy** is a major cause of preventable blindness and was specifically targeted by Vision 2020 efforts due to its increasing prevalence globally. - Early detection and treatment through retinal screening are crucial components of preventing vision loss from diabetic retinopathy. *Refractive Errors* - **Uncorrected refractive errors** are a leading cause of visual impairment worldwide, and their correction with spectacles is a simple and cost-effective intervention. - Vision 2020 emphasized accessible and affordable refractive error services to improve vision in affected populations. *Cataract* - **Cataract** is the leading cause of blindness globally, and its surgical removal is a highly effective and widely accessible treatment. - Vision 2020 prioritized increasing the number of cataract surgeries to restore sight to millions.
Question 7: Constantly changing refractive error is seen in:
- A. Morgagnian cataract
- B. Intumescent cataract
- C. Traumatic cataract
- D. Diabetic cataract (Correct Answer)
Explanation: ***Diabetic cataract*** - Fluctuating blood glucose levels in diabetes can cause changes in the **osmolarity of the aqueous humor**, which in turn affects the hydration of the lens and its refractive power. - This leads to a **constantly changing refractive error**, where a person's prescription might change rapidly over short periods of time. *Morgagnian cataract* - This is a type of **hypermature cataract** where the cortex has liquefied, allowing the nucleus to sink within the capsular bag. - While vision is severely impaired, it doesn't typically present with a constantly changing refractive error, but rather a stable, significant vision loss. *Intumescent cataract* - An **intumescent cataract** is a mature or hypermature cataract where the lens has become significantly swollen due to water absorption. - This swelling causes the anterior capsule to stretch, but it results in a fixed and profound vision loss, not a fluctuating refractive error. *Traumatic cataract* - A **traumatic cataract** develops as a result of blunt or penetrating ocular injury, causing damage to the lens fibers. - While the specific type of refractive error can vary depending on the trauma, it typically presents as a stable visual impairment rather than a constantly changing refractive error.
Question 8: A diabetic patient presents to you with visual acuity of 6/9 in one eye. Further investigations revealed preretinal hemorrhages with neovascularization at the optic disc. What is the next step in management?
- A. Focal laser photocoagulation
- B. Pan-retinal photocoagulation (Correct Answer)
- C. Grid laser photocoagulation
- D. Scleral buckling
Explanation: ***Pan-retinal photocoagulation*** - The presence of **preretinal hemorrhages** and **neovascularization at the optic disc (NVD)** indicates **high-risk proliferative diabetic retinopathy (PDR)**. - **NVD is a high-risk characteristic** for severe vision loss and requires urgent treatment with **pan-retinal photocoagulation (PRP)**. - PRP aims to ablate ischemic peripheral retina, which reduces the production of **VEGF** and other angiogenic factors that stimulate neovascularization. *Focal laser photocoagulation* - This treatment targets discrete leaking microaneurysms in cases of **clinically significant macular edema (CSME)**, which is not the primary issue here. - It is used for **non-proliferative diabetic retinopathy** with macular involvement, not for neovascularization. *Grid laser photocoagulation* - Grid laser is a type of focal laser used for **diffuse macular edema** where specific leaking microaneurysms cannot be identified. - It is not indicated for **neovascularization** or **preretinal hemorrhages**, which are signs of PDR. *Scleral buckling* - **Scleral buckling** is a surgical procedure primarily used to treat **retinal detachment** by indenting the sclera to relieve vitreoretinal traction. - It is not the initial or primary treatment for **proliferative diabetic retinopathy** or **neovascularization**.
Question 9: The most common cause of early spontaneous abortion is:
- A. Teratogens
- B. Endocrine disorder
- C. Infection
- D. Chromosomal abnormality (Correct Answer)
Explanation: ***Chromosomal abnormality*** - **Chromosomal abnormalities**, such as aneuploidy (e.g., trisomy, monosomy), are responsible for approximately 50-70% of all **early spontaneous abortions**. - These abnormalities often result in **non-viable embryos** or fetuses, leading to pregnancy loss before 12-20 weeks of gestation. *Teratogens* - **Teratogens** are agents that can cause birth defects, but they are a less common cause of **early spontaneous abortion** compared to chromosomal abnormalities. - While they can lead to fetal demise, their primary impact is often on **fetal development** rather than embryonic non-viability. *Endocrine disorder* - **Endocrine disorders** like uncontrolled diabetes or thyroid disease can increase the risk of spontaneous abortion, but they are not the **most common cause**. - These factors tend to contribute to a smaller percentage of **early pregnancy losses** compared to genetic errors. *Infection* - Certain **infections** (e.g., TORCH infections, bacterial vaginosis) can cause spontaneous abortion, especially if systemic or severe. - However, similar to endocrine disorders, infections are a less frequent cause of **early spontaneous abortion** than chromosomal abnormalities.
Question 10: In the management of diabetes mellitus, lactic acidosis is caused by which of the following?
- A. Pioglitazone
- B. Metformin (Correct Answer)
- C. Glipizide
- D. Tolbutamide
Explanation: ***Metformin*** - Metformin can cause **lactic acidosis**, especially in patients with **renal impairment**, as it inhibits hepatic gluconeogenesis and lactate clearance [1]. - The risk is increased in conditions leading to **tissue hypoperfusion** or **hypoxemia**, where lactate production is elevated. *Pioglitazone* - **Pioglitazone** is a thiazolidinedione that improves insulin sensitivity but is not associated with lactic acidosis [1]. - Its main risks include **fluid retention**, **heart failure**, and increased risk of **bladder cancer**. *Glipizide* - **Glipizide** is a sulfonylurea that stimulates insulin secretion from beta cells but does not cause lactic acidosis [2]. - The primary adverse effect is **hypoglycemia** [2]. *Tolbutamide* - **Tolbutamide** is an older generation sulfonylurea, similar to glipizide, and also acts by stimulating insulin release [2]. - Its main risk is **hypoglycemia**, and it is not associated with lactic acidosis [2].
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