Anatomy
1 questionsMost common site for medulloblastoma is-
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 611: Most common site for medulloblastoma is-
- A. Cerebellum (Correct Answer)
- B. Pituitary
- C. Cerebrum
- D. Pineal gland
Explanation: ***Cerebellum*** - **Medulloblastoma** is a highly malignant primary brain tumor that characteristically arises in the **cerebellum** [1]. - It is the most common malignant brain tumor in children, typically originating from the **roof of the fourth ventricle**. *Pituitary* - The **pituitary gland** is mostly associated with **adenomas**, which are benign tumors arising from anterior pituitary cells. - Tumors like **craniopharyngiomas** can also be found in the sellar region, but medulloblastomas do not originate here. *Cerebrum* - The **cerebrum** is the most common site for **gliomas** (e.g., glioblastoma multiforme) and metastatic tumors in adults. - Medulloblastoma specifically originates from primitive neuroectodermal cells in the posterior fossa [1]. *Pineal gland* - The **pineal gland** is associated with **pinealomas** (e.g., pineoblastoma, pineocytoma) and **germinomas** [2]. - These are distinct from medulloblastomas in their cellular origin and typical anatomical location.
Ophthalmology
4 questionsWhich of the following is not a risk factor for angle closure glaucoma?
The 'headlight in fog' appearance is seen in which condition?
What visual disturbance is caused by an optic tract lesion?
How is the angle of squint measured?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 611: Which of the following is not a risk factor for angle closure glaucoma?
- A. Small eye
- B. Small cornea
- C. Small lens (Correct Answer)
- D. Hypermetropia
Explanation: ***Correct Answer: Small lens*** - A smaller lens would lead to a **deeper anterior chamber**, reducing the likelihood of iridotrabecular contact and angle closure. - In contrast, a **large or thick lens** is a well-established risk factor for angle closure glaucoma as it pushes the iris forward, causing pupillary block. - Small lens size is **NOT a risk factor** for angle closure glaucoma. *Incorrect: Small eye* - A small eye (e.g., in **nanophthalmos**) is associated with a relatively large lens in proportion to the eye size, which can push the iris forward and narrow the angle. - This anatomical configuration makes individuals more prone to **pupillary block** and angle closure. *Incorrect: Hypermetropia* - **Hyperopic eyes** tend to be shorter with reduced axial length, which often results in a shallower anterior chamber and a relatively crowded anterior segment. - This shallow anterior chamber increases the risk of the iris occluding the **trabecular meshwork**, predisposing to angle closure. *Incorrect: Small cornea* - A small corneal diameter can be indicative of a generally smaller anterior segment, often correlating with a **shallow anterior chamber**. - A smaller cornea contributes to a more crowded anterior segment, predisposing to **angle closure glaucoma**.
Question 612: The 'headlight in fog' appearance is seen in which condition?
- A. Syphilis
- B. Toxocara
- C. Herpes
- D. Toxoplasmosis (Correct Answer)
Explanation: ***Toxoplasmosis*** - The "headlight in fog" appearance is a classic description of **chorioretinitis** caused by **congenital toxoplasmosis**. - It refers to an old, healed **retinal scar** (headlight) surrounded by active inflammation and **vitreous haze** (fog). *Syphilis* - Ocular syphilis can cause various presentations, including uveitis, retinitis, and optic neuropathy, but it does **not typically** present with the specific "headlight in fog" appearance. - Ocular lesions are often more diffuse or involve distinct **gummatous lesions**. *Toxocara* - Ocular toxocariasis often presents as a **granuloma** (either peripheral or macular) or as **endophthalmitis**, but not the characteristic "headlight in fog" pattern. - The lesions are usually a result of a direct larval migration and subsequent inflammatory reaction. *Herpes* - Herpes simplex virus (HSV) or varicella-zoster virus (VZV) can cause **acute retinal necrosis** (ARN) or progressive outer retinal necrosis (PORN), presenting with widespread retinal whitening and vascular occlusion. - These conditions have distinct appearances, generally **lacking the central scar** with surrounding active inflammation seen in "headlight in fog."
Question 613: What visual disturbance is caused by an optic tract lesion?
- A. Marcus Gunn pupil
- B. Bilateral blindness
- C. Contralateral homonymous hemianopsia (Correct Answer)
- D. Ipsilateral homonymous hemianopsia
Explanation: ***Contralateral homonymous hemianopsia*** - An **optic tract lesion** interrupts the nerve fibers originating from the contralateral nasal retina and the ipsilateral temporal retina, leading to **vision loss in the contralateral visual field** of both eyes. - This results in a defect where the patient cannot see objects on the **opposite side** of the body from the lesion. *Marcus Gunn pupil* - A **Marcus Gunn pupil**, also known as an **afferent pupillary defect**, indicates asymmetric disease of the **retina** or **optic nerve**, not specifically the optic tract. - It is characterized by paradoxical dilation of the affected pupil when light is swung from the unaffected to the affected eye. *Bilateral blindness* - **Bilateral blindness** typically results from severe damage to both **optic nerves**, the **optic chiasm**, or extensive bilateral lesions in the visual cortex. - An optic tract lesion affects only one side of the visual pathway posterior to the chiasm, thus not causing complete bilateral vision loss. *Ipsilateral homonymous hemianopsia* - **Ipsilateral homonymous hemianopsia** is not a standard neurological visual field defect. Visual field defects are usually described relative to the lesion side as contralateral or ipsilateral based on the specific anatomical location. - An optic tract lesion always produces a **contralateral homonymous hemianopsia** because optic tract fibers cross at the optic chiasm.
Question 614: How is the angle of squint measured?
- A. Gonioscopy
- B. Prism (Correct Answer)
- C. Retinoscopy
- D. Keratometry
Explanation: ***Prism*** - The **angle of squint**, which indicates the deviation of the eyes, is most accurately measured using **prisms** in conjunction with the **prism cover test** or **alternate prism cover test**. - Prisms quantify the degree of ocular deviation in **prism diopters** by neutralizing the misalignment so that the light falls correctly on the fovea. *Gonioscopy* - This technique is used to examine the **anterior chamber angle** of the eye, which is relevant for diagnosing conditions like **glaucoma**. - It does not involve measuring the angle of ocular deviation or misalignment of the eyes. *Retinoscopy* - Retinoscopy is an objective method to determine the **refractive error** of the eye (e.g., myopia, hyperopia, astigmatism). - While it assesses the eye's ability to focus light, it does not directly measure the angle of a squint. *Keratometry* - Keratometry measures the **curvature of the cornea**, primarily used for fitting contact lenses or calculating intraocular lens power for cataract surgery. - It does not assess the alignment of the eyes or the magnitude of a squint.
Pathology
3 questionsIn which condition is retinal astrocytoma commonly seen?
Orphan Annie nuclei are characteristic of which of the following?
Which of the following is the most likely proliferating breast mass?
NEET-PG 2012 - Pathology NEET-PG Practice Questions and MCQs
Question 611: In which condition is retinal astrocytoma commonly seen?
- A. Tuberous sclerosis (Correct Answer)
- B. Sturge weber syndrome
- C. Von Hippel-Lindau syndrome
- D. Neurofibromatosis
Explanation: ***Tuberous sclerosis*** - **Retinal astrocytoma**, also known as **retinal astrocytic hamartoma**, is a common ocular manifestation of **tuberous sclerosis complex (TSC)** [1]. - These lesions can appear as **mulberry-like nodules** or flat, whitish patches on the retina. - Found in approximately **40-50% of patients** with tuberous sclerosis. *Sturge weber syndrome* - Characterized by a **port-wine stain (facial nevus flammeus)**, **leptomeningeal angioma**, and **glaucoma**. - Ocular manifestations include **choroidal hemangiomas** and increased episcleral venous pressure. - Does not typically involve **retinal astrocytomas**. *Von Hippel-Lindau syndrome* - Associated with **retinal capillary hemangioblastomas** (vascular tumors) and various tumors in other organs like the kidneys, pancreas, and brain. - This condition involves **vascular tumors** in the retina, not astrocytic tumors. - Important differential as it also presents with retinal lesions. *Neurofibromatosis* - A neurocutaneous syndrome characterized by **café-au-lait spots**, **neurofibromas**, and **Lisch nodules** (iris hamartomas). - Ocular manifestations include **optic nerve gliomas** and iris hamartomas, but **not retinal astrocytomas**. - NF-1 is the most common neurocutaneous syndrome but has different retinal pathology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1318-1319.
Question 612: Orphan Annie nuclei are characteristic of which of the following?
- A. Paraganglioma with Zellballen pattern
- B. Meningioma with psammoma bodies
- C. Pituitary adenoma with atypical nuclei
- D. Papillary thyroid carcinoma (Correct Answer)
Explanation: ***Papillary carcinoma thyroid***[1][2] - Characterized by **Orphan Annie nuclei**[1], which are large and round with a clear or empty appearance due to the presence of intranuclear cytoplasmic inclusions[1]. - Often associated with **thyroid follicular structures** and is the most common type of thyroid cancer[2]. *Meningioma* - Typically presents with **dural-based tumors** and does not exhibit Orphan Annie nuclei. - Histologically, it may demonstrate **whorled patterns** or calcifications instead. *Carcinoma pituitary* - Involves **adenomatous changes** in the pituitary gland but does not demonstrate the characteristic Orphan Annie nuclei. - More commonly shows **varied cellular morphology** depending on the type of secretory cells (e.g., prolactin, ACTH). *Paraganglioma* - Derived from **neuroendocrine cells**, and presents with **zellballen pattern** rather than Orphan Annie nuclei. - Often shows **chromaffin cells** and is typically associated with catecholamine secretion. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1099. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 429-430.
Question 613: Which of the following is the most likely proliferating breast mass?
- A. Duct ectasia
- B. Adenosis
- C. Papilloma
- D. Fibroadenoma (Correct Answer)
Explanation: **Fibroadenoma** - A **fibroadenoma** is a benign **biphasic breast tumor** composed of both glandular and stromal tissue, making it a common proliferating mass [3]. - It is often seen in **young women** and typically presents as a firm, movable, non-tender lump [3]. *Duct ectasia* - **Duct ectasia** is a non-proliferative condition characterized by dilation of the **subareolar ducts**, often with inflammation and fibrosis. - It is more commonly associated with **nipple discharge** and **periductal inflammation** rather than being a primary proliferating mass. *Adenosis* - **Adenosis** refers to an increase in the number of **glands or lobules** within the breast parenchyma, which can be sclerosing or florid [2]. - While it involves increased glandular elements, it is generally considered a **benign proliferative change** and less likely to form a distinct, palpable mass compared to a fibroadenoma [1], [4]. *Papilloma* - A **papilloma** is a benign epithelial proliferation within a **duct**, characterized by a central fibrovascular core [2]. - It commonly presents with **nipple discharge**, often bloody, and is typically a smaller lesion within the ductal system rather than a large, palpable proliferating mass [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1052-1054. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 446-447. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 448-449. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1052.
Pharmacology
2 questionsWhat is the best drug for open-angle glaucoma?
Which of the following best describes a Type B adverse drug reaction?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 611: What is the best drug for open-angle glaucoma?
- A. Latanoprost (Correct Answer)
- B. Pilocarpine
- C. Physostigmine
- D. Apraclonidine
Explanation: Latanoprost - Latanoprost is a prostaglandin analog and is often considered a first-line treatment for open-angle glaucoma due to its efficacy in reducing intraocular pressure (IOP) and its once-daily dosing. - It works by increasing the outflow of aqueous humor through the uveoscleral pathway, thereby lowering IOP. Pilocarpine - Pilocarpine is a cholinergic agonist that causes miosis and ciliary muscle contraction [3], increasing the outflow of aqueous humor through the trabecular meshwork [4]. - While effective, its side effects (e.g., accommodative spasm, miosis) [1] and more frequent dosing make it generally a second-line or third-line agent for long-term management compared to prostaglandins. Physostigmine - Physostigmine is an acetylcholinesterase inhibitor that indirectly increases acetylcholine, mimicking cholinergic stimulation. - Although it can lower IOP, it is generally not used for open-angle glaucoma due to significant side effects and the availability of safer, more effective alternatives [1]. Apraclonidine - Apraclonidine is an alpha-2 adrenergic agonist [2] used primarily for short-term control of IOP, especially before or after ocular surgery, or as an adjunct therapy. - Its efficacy as a long-term monotherapy for open-angle glaucoma is limited by tachyphylaxis and potential for significant systemic side effects with chronic use.
Question 612: Which of the following best describes a Type B adverse drug reaction?
- A. Augmented effect of drug
- B. Effect seen on chronic use of drug
- C. Delayed effect of drug
- D. Unpredictable bizarre reaction (Correct Answer)
Explanation: ***Unpredictable bizarre reaction*** - Type B reactions are **unpredictable**, **bizarre**, and not directly related to the drug's known pharmacological actions. - They often involve **immunological reactions** or genetic predispositions, such as allergies or idiosyncratic responses. *Augmented effect of drug* - This describes a **Type A** adverse drug reaction, which is predictable and results from an **exaggerated pharmacological effect** of the drug. - It is typically dose-dependent and can be managed by adjusting the dosage. *Effect seen on chronic use of drug* - This description can apply to several types of adverse reactions, but it commonly relates to **Type C (chronic) reactions**, where effects occur only after prolonged exposure. - These reactions might be due to **cumulative toxicity** or adaptive changes in the body. *Delayed effect of drug* - This aligns with **Type D (delayed) adverse drug reactions**, which manifest long after the drug exposure has ended or after a period of latency. - Examples include **carcinogenesis** or teratogenesis, occurring months or years later.