Anatomy
1 questionsPupillary reflex pathway - All of the following are a part except?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 911: Pupillary reflex pathway - All of the following are a part except?
- A. Edinger Westphal nucleus
- B. Medial geniculate body (Correct Answer)
- C. Pretectal nuclei
- D. Retinal ganglion cell
Explanation: ***Medial geniculate body*** - The **medial geniculate body** is part of the **auditory pathway**, involved in processing sound information [2]. - It does not play a role in the **afferent** or **efferent** limbs of the pupillary light reflex. *Edinger Westphal nucleus* - The **Edinger-Westphal nucleus** is the **parasympathetic nucleus** of cranial nerve III (**oculomotor nerve**) [1]. - It provides preganglionic parasympathetic fibers that lead to pupillary constriction via the **ciliary ganglion** [1]. *Pretectal nuclei* - The **pretectal nuclei** receive input from the **retina** and are critical for the **afferent limb** of the pupillary light reflex [1], [3]. - They send fibers to the **Edinger-Westphal nuclei** bilaterally, mediating the direct and consensual light reflexes [1]. *Retinal ganglion cell* - **Retinal ganglion cells** are responsible for transmitting visual information from the **retina** to the brain [4]. - A subset of these cells, containing **melanopsin**, are photosensitive and specifically mediate the input for the **pupillary light reflex** [3].
Internal Medicine
5 questionsA patient involved in an accident presents with unconsciousness. Upon physical examination, there is unilateral pupillary dilatation. What is the most likely cause of this finding?
Which of the following symptoms is least likely to be associated with hyponatremia?
What is the most common cause of lung abscess in comatose patients?
Which of the following is least likely to be associated with emphysema?
Clicking noise in Pneumomediastinum is known as
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 911: A patient involved in an accident presents with unconsciousness. Upon physical examination, there is unilateral pupillary dilatation. What is the most likely cause of this finding?
- A. Uncal herniation (Correct Answer)
- B. Tonsillar herniation
- C. Cingulate herniation
- D. Transcalvarial herniation
Explanation: ***Uncal herniation*** - **Uncal herniation** compresses the **ipsilateral oculomotor nerve (CN III)**, leading to **pupillary dilation** due to predominant parasympathetic fiber damage [1], [2]. - This condition occurs when the **medial temporal lobe (uncus)** is forced over the tentorial notch, often as a result of a **supratentorial mass effect** [2]. *Tonsillar herniation* - **Tonsillar herniation** is the downward displacement of the **cerebellar tonsils** through the **foramen magnum** [1], [2]. - This compression primarily affects the **brainstem** and **cardiorespiratory centers**, causing **respiratory arrest** or **cardiac dysfunction**, not direct pupillary dilation [1]. *Cingulate herniation* - **Cingulate herniation** involves the displacement of the **cingulate gyrus** under the **falx cerebri**. - While it can lead to **hydrocephalus** and **cognitive changes**, it does not directly cause **unilateral pupillary dilation**. *Transcalvarial herniation* - **Transcalvarial herniation** occurs when **brain tissue** extends through a **skull defect** (e.g., following a craniectomy or skull fracture). - This type of herniation is typically visible externally and does not inherently cause **unilateral pupillary dilation** through direct nerve compression.
Question 912: Which of the following symptoms is least likely to be associated with hyponatremia?
- A. anorexia
- B. Drowsiness
- C. Convulsions
- D. Myalgia (Correct Answer)
Explanation: Myalgia - While muscle cramps can occur with electrolyte imbalances, generalized myalgia (muscle pain) is not a typical or primary symptom of hyponatremia. - Hyponatremia primarily affects neurological function due to osmotic shifts in the brain. anorexia - Anorexia (loss of appetite) is a common, non-specific symptom of many metabolic disturbances, including hyponatremia, and often accompanies nausea and vomiting. - It arises from the general malaise and gastrointestinal upset associated with the condition. Convulsions - Convulsions are a severe neurological symptom of acute and profound hyponatremia, resulting from cerebral edema and increased intracranial pressure [1]. - This occurs when the brain swells due to the osmotic shift of water into brain cells. Drowsiness - Drowsiness is a frequent neurological manifestation of hyponatremia, indicative of altered mental status [1]. - It reflects impaired brain function due to the osmotic disturbances and potential cerebral edema [1].
Question 913: What is the most common cause of lung abscess in comatose patients?
- A. Staph aureus
- B. Oral anaerobes (Correct Answer)
- C. Klebsiella
- D. Tuberculosis
Explanation: Oral anaerobes - **Comatose patients** are at high risk for **aspiration** of oropharyngeal flora, which predominantly consists of anaerobic bacteria. [1] - Aspiration of these organisms, especially in compromised lung tissue, frequently leads to **necrotizing pneumonia** and subsequent abscess formation. [1] *Staph aureus* - While *Staphylococcus aureus* can cause lung abscesses, particularly in the context of **hematogenous spread** (e.g., endocarditis) or nosocomial infections, it is not the most common cause in *comatose patients* who typically aspirate oral flora. [2] - *S. aureus* lung abscesses are often associated with multiple, smaller lesions rather than a single, large abscess from aspiration. *Klebsiella* - *Klebsiella pneumoniae* can cause severe, **rapidly progressive pneumonia** that may lead to abscess formation, especially in individuals with **alcoholism** or **diabetes**. - However, it is less common than oral anaerobes as the primary cause of abscess in the general population of comatose patients, whose main risk factor is aspiration of normal oral flora. [1] *Tuberculosis* - **Mycobacterium tuberculosis** can cause cavitary lung lesions, but these are typically chronic and result from primary or reactivated tuberculosis disease, not acute aspiration. [3] - Lung abscesses caused by tuberculosis are histologically distinct from pyogenic abscesses and are characterized by **granulomatous inflammation** and caseous necrosis.
Question 914: Which of the following is least likely to be associated with emphysema?
- A. Associated with smoking
- B. Type I respiratory failure (Correct Answer)
- C. Barrel shaped chest
- D. Cyanosis
Explanation: **Type I respiratory failure** - **Emphysema** primarily causes **Type II respiratory failure** (hypercapnic) due to impaired gas exchange and CO2 retention resulting from alveolar destruction and air trapping [2][4]. - While hypoxemia can occur in severe emphysema, it is the more prominent **hypercapnia** that defines its typical respiratory failure pattern, making pure Type I less likely [3][4]. *Associated with smoking* - **Cigarette smoking** is the leading cause of emphysema, directly linked to the destruction of alveolar walls and loss of elastic recoil [1]. - The inhaled toxins trigger an inflammatory response in the lungs, leading to the release of proteases that break down lung tissue [1][2]. *Barrel shaped chest* - This is a classic sign of advanced emphysema, caused by **chronic air trapping** and subsequent hyperinflation of the lungs [2]. - The diaphragm flattens, and the ribs become more horizontal, increasing the anterior-posterior diameter of the chest. *Cyanosis* - Often seen in patients with severe emphysema (especially in a subgroup referred to as "blue bloaters" for chronic bronchitis overlap) due to **significant hypoxemia** [3]. - Impaired gas exchange leads to insufficient oxygenation of hemoglobin, causing a bluish discoloration of the skin and mucous membranes [3].
Question 915: Clicking noise in Pneumomediastinum is known as
- A. Hamman's sign (Correct Answer)
- B. Traube's sign
- C. Kussmaul's sign
- D. None of the options
Explanation: Hamman's sign - Hamman's sign is a crunching, bubbling, or clicking sound synchronous with the heartbeat, audible on auscultation over the precordium. - It is pathognomonic for pneumomediastinum, caused by the heart beating against air-filled tissues. Traube's sign - Traube's sign refers to a pistol-shot sound heard over the femoral artery in severe aortic regurgitation [1]. - It is a vascular sign and not related to pneumomediastinum. Kussmaul's sign - Kussmaul's sign is a paradoxical rise in jugular venous pressure (JVP) during inspiration. - It is typically seen in conditions like constrictive pericarditis or right ventricular infarction, not pneumomediastinum. None of the options - This option is incorrect because Hamman's sign accurately describes the clicking noise associated with pneumomediastinum. - The other options refer to different clinical phenomena unrelated to pneumomediastinum.
Ophthalmology
4 questionsSilk retina is seen in ?
Pseudopapilledema with tigroid fundus appearance is seen in?
1mm change in axial length of the eyeball would change the refracting power of the eye by?
A 30 year old man presents to the clinic with pain in the eye, watering, redness, and photophobia. Examination of his eyes shows circumcorneal congestion and keratic precipitates. Assertion: Keratic precipitates (KPs) are proteinaceous deposits that can occur in various patterns on the corneal endothelium. Reason: Mutton fat KPs are seen in granulomatous iridocyclitis and are composed of epithelioid cells and macrophages.
NEET-PG 2015 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 911: Silk retina is seen in ?
- A. Retinal detachment (Correct Answer)
- B. Diabetic retinopathy
- C. Macular degeneration
- D. Hypertensive retinopathy
Explanation: ***Retinal detachment*** - **"Silk retina" or "silky sheen"** is a classic ophthalmoscopic finding in retinal detachment, describing the **smooth, glistening appearance** of the detached sensory retina. - The detached retina appears **elevated, gray, and translucent** with characteristic folds or undulations, exhibiting a **satiny or silky luster** when examined. - Patients typically present with **photopsias (flashes of light)**, **floaters**, and progressive **visual field defect** described as a "curtain" or "shadow." - This is a true **ophthalmic emergency** requiring urgent surgical intervention. *Diabetic retinopathy* - Characterized by **microaneurysms, dot-blot hemorrhages, hard exudates**, and **cotton-wool spots** in non-proliferative stages. - Proliferative diabetic retinopathy shows **neovascularization** and vitreous hemorrhage. - Does not produce the "silk retina" appearance. *Macular degeneration* - Age-related macular degeneration presents with **drusen, pigmentary changes**, and in advanced stages, **geographic atrophy** or **choroidal neovascularization**. - May show a **"beaten-bronze" appearance** in certain macular dystrophies (Best's disease), but not "silk retina." - Central vision loss is the predominant symptom. *Hypertensive retinopathy* - Features include **generalized arteriolar narrowing, AV nicking, flame-shaped hemorrhages**, and **cotton-wool spots**. - In severe cases (Grade IV), **optic disc edema** and macular star exudates may occur. - Vascular changes dominate the clinical picture, not a silky retinal appearance.
Question 912: Pseudopapilledema with tigroid fundus appearance is seen in?
- A. Astigmatism
- B. Presbyopia
- C. Hypermetropia
- D. Myopia (Correct Answer)
Explanation: ***Myopia*** - **Pseudopapilledema** with a **tigroid fundus** (tessellated or salt-and-pepper appearance) is characteristically observed in high myopia due to the oblique entry of the **optic nerve** into the globe and thinning of the choroid and retinal pigment epithelium. - The pseudopapilledema is caused by the crowding of axons and glial tissue within the optic disc, giving a raised appearance, and is distinct from true papilledema which involves **optic disc edema** due to increased **intracranial pressure**. - The tigroid fundus results from the visibility of underlying **choroidal vessels** through the attenuated retinal pigment epithelium in the stretched, elongated myopic eye. *Hypermetropia* - **Hypermetropia** (farsightedness) typically presents with a small, compact optic disc, but does not exhibit the specific findings of **pseudopapilledema** or tigroid fundus. - This condition is characterized by the eye being too short or the lens having insufficient power, causing light to focus behind the retina. *Astigmatism* - **Astigmatism** is characterized by an **irregularly shaped cornea** or lens, leading to blurred vision at all distances. - While it can cause some distortion, it is not associated with the specific optic disc appearance of **pseudopapilledema** or the fundus changes seen in high myopia. *Presbyopia* - **Presbyopia** is an age-related condition where the eye's natural lens loses its flexibility, making it difficult to focus on **near objects**. - It affects the **accommodative ability** of the eye and does not manifest with any characteristic changes in the optic disc morphology such as **pseudopapilledema** or retinal/choroidal changes.
Question 913: 1mm change in axial length of the eyeball would change the refracting power of the eye by?
- A. 1D
- B. 2D
- C. 3D (Correct Answer)
- D. 4D
Explanation: ***3D*** - A 1mm change in the **axial length** of the eyeball leads to an approximate **3 diopter (D) change** in the refractive power of the eye. - This relationship is crucial for understanding **refractive errors** like myopia (if the eyeball is too long) or hyperopia (if it's too short). *1D* - A 1D change in refractive power corresponds to a much larger change in the **focal length** of the eye, not typically 1mm in axial length. - This value is too small to reflect the significant impact of a 1mm axial length alteration on the eye's focusing ability. *2D* - While a direct relationship exists, 2D is an **underestimation** of the actual refractive change caused by a 1mm alteration in axial length. - This value would imply a less sensitive optical system than the human eye. *4D* - A 4D change would represent an **overestimation** of the refractive power change for a 1mm alteration in axial length. - Such a high value is generally seen with more substantial anatomical variations or surgical interventions.
Question 914: A 30 year old man presents to the clinic with pain in the eye, watering, redness, and photophobia. Examination of his eyes shows circumcorneal congestion and keratic precipitates. Assertion: Keratic precipitates (KPs) are proteinaceous deposits that can occur in various patterns on the corneal endothelium. Reason: Mutton fat KPs are seen in granulomatous iridocyclitis and are composed of epithelioid cells and macrophages.
- A. Both Assertion and Reason are true, and Reason is the correct explanation for Assertion
- B. Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion (Correct Answer)
- C. Assertion is true, but Reason is false
- D. Assertion is false but reason is true
Explanation: ***Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion*** **Why both statements are true:** - The **Assertion** is correct: Keratic precipitates (KPs) are inflammatory cell and protein deposits that adhere to the **corneal endothelium** and can present in various patterns including fine dusty KPs, medium-sized KPs, and large mutton fat KPs. - The **Reason** is also correct: **Mutton fat KPs** are characteristic of **granulomatous anterior uveitis** (granulomatous iridocyclitis) and consist of aggregations of **epithelioid cells and macrophages**, appearing as large, greasy, white deposits. **Why Reason does NOT explain Assertion:** - The Reason describes a **specific type** of KP (mutton fat) and its cellular composition in one particular form of inflammation (granulomatous). - The Assertion makes a **general statement** about KPs occurring in various patterns. - The Reason does not explain **why** KPs can occur in various patterns or what determines these different patterns - it only describes one specific pattern. *Incorrect: Both true with Reason explaining Assertion* - The Reason is too specific and only describes one type of KP, not the general mechanism of pattern variation. *Incorrect: Assertion true, Reason false* - Both statements are medically accurate and well-established in ophthalmology literature. *Incorrect: Assertion false, Reason true* - KPs are well-documented deposits on the corneal endothelium in various forms of uveitis, making the Assertion true.