Anatomy
2 questionsNasopharyngeal chordoma arises from:-
During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?
NEET-PG 2018 - Anatomy NEET-PG Practice Questions and MCQs
Question 201: Nasopharyngeal chordoma arises from:-
- A. Luschka's bursa
- B. Pharyngeal bursa
- C. Rathke's pouch
- D. Notochord (Correct Answer)
Explanation: Correct Option: Notochord - **Chordomas** are rare malignant tumors that arise from embryonic remnants of the **notochord** [1] - The notochord is a flexible rod-like structure that forms the primitive axial skeleton during embryonic development - Chordomas typically occur along the **midline** at sites where notochordal remnants persist, most commonly at the **skull base (clivus/nasopharynx)** and **sacrococcygeal region** [1] Incorrect Option: Luschka's bursa - **Luschka's bursa** (also known as the pharyngeal bursa) is a small indentation or pocket in the nasopharynx posterior to the pharyngeal tonsil - While located in the nasopharynx, it is a **normal anatomical structure**, not an embryological remnant that gives rise to tumors - Not associated with chordoma development Incorrect Option: Pharyngeal bursa - **Pharyngeal bursa** is another term for **Luschka's bursa** (they are synonymous) - It is a normal anatomical structure in the nasopharynx - Not related to the embryonic remnants that give rise to chordomas Incorrect Option: Rathke's pouch - **Rathke's pouch** is an embryonic invagination of the stomodeum (primitive oral cavity) that gives rise to the **anterior pituitary gland** - Tumors arising from remnants of Rathke's pouch are **craniopharyngiomas**, which are distinct from chordomas - Craniopharyngiomas are typically suprasellar, while chordomas are more commonly found at the clivus or sacrum
Question 202: During acute tonsillitis, referred pain from the tonsil to the middle ear occurs via which nerve?
- A. Facial nerve
- B. Glossopharyngeal nerve (Correct Answer)
- C. Trigeminal nerve
- D. Vagus nerve
Explanation: ***Glossopharyngeal nerve*** - The **glossopharyngeal nerve (CN IX)** provides sensory innervation to the palatine tonsil via its tonsillar branches - CN IX also supplies the middle ear via the **tympanic nerve (Jacobson's nerve)**, which forms the tympanic plexus - This shared sensory pathway explains **referred otalgia** (ear pain) during acute tonsillitis - Inflammation of the tonsil stimulates CN IX, and the brain misinterprets this as pain from the middle ear *Facial nerve* - The **facial nerve (CN VII)** primarily provides motor innervation to muscles of facial expression and taste to the anterior two-thirds of the tongue - While it has a small sensory component (nervus intermedius) for the external auditory canal, it does not innervate the tonsil - Cannot serve as the pathway for referred pain from tonsil to middle ear *Trigeminal nerve* - The **trigeminal nerve (CN V)** provides sensory innervation to the face, anterior scalp, and oral cavity - Does not innervate the palatine tonsil or the middle ear cavity - Not involved in tonsillar referred otalgia *Vagus nerve* - The **vagus nerve (CN X)** provides sensory innervation to parts of the pharynx, larynx, and external auditory canal (via Arnold's nerve) - While it contributes to pharyngeal sensation, the **glossopharyngeal nerve is the primary pathway** for referred otalgia from tonsillar inflammation due to its direct innervation of both the tonsil and middle ear
Internal Medicine
1 questionsWhich of the following hematological problems may be precipitated by parvovirus?
NEET-PG 2018 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 201: Which of the following hematological problems may be precipitated by parvovirus?
- A. Aplastic crisis (Correct Answer)
- B. Hemolytic crisis
- C. Thrombocytopenia
- D. Pancytopenia
Explanation: ***Aplastic crisis*** - Parvovirus B19 preferentially infects and destroys **erythroid progenitor cells** in the bone marrow, leading to a temporary halt in red blood cell production [1]. - This can precipitate an **aplastic crisis**, especially in individuals with underlying chronic hemolytic anemias (e.g., **sickle cell disease** or **hereditary spherocytosis**), where red blood cell lifespan is already shortened [2]. *Hemolytic crisis* - A hemolytic crisis involves an **accelerated destruction of red blood cells**, leading to a sudden drop in hemoglobin. - While parvovirus can indirectly worsen anemia, it primarily affects red cell production rather than directly increasing their destruction, acting more as a trigger for a production problem than a hemolytic one [1]. *Thrombocytopenia* - **Thrombocytopenia** is characterized by a low platelet count, which can lead to bleeding disorders. - While viral infections can sometimes cause mild myelosuppression affecting platelets, parvovirus B19 is not typically associated with severe or primary thrombocytopenia. *Pancytopenia* - **Pancytopenia** is a reduction in all three blood cell lines (red blood cells, white blood cells, and platelets). - While parvovirus can cause a transient aplastic crisis (affecting red cells), it rarely causes a severe, sustained suppression of all cell lines to be classified as true pancytopenia, though some transient leukopenia may occur [1].
Obstetrics and Gynecology
2 questionsWhich of the following is an indication for use of Hormone Replacement Therapy in menopausal women:-
Which among the following is not a premalignant lesion of vulva?
NEET-PG 2018 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 201: Which of the following is an indication for use of Hormone Replacement Therapy in menopausal women:-
- A. Post menopausal bleeding
- B. Hot flushes (Correct Answer)
- C. Cardiovascular protection
- D. Pyelonephritis
Explanation: ***Hot flushes*** - Hormone Replacement Therapy (HRT) is highly effective in alleviating **vasomotor symptoms** like hot flushes and night sweats, which can severely impact quality of life in menopausal women. - The primary goal of using HRT is to manage these **menopausal symptoms** when they are bothersome. *Post menopausal bleeding* - **Postmenopausal bleeding** is a contraindication, not an indication, for new HRT initiation as it requires investigation to rule out endometrial pathology, including cancer. - If a woman on HRT experiences bleeding, it warrants immediate investigation to determine its cause and may necessitate stopping or changing the HRT regimen. *Cardiovascular protection* - While earlier beliefs suggested HRT offered cardiovascular protection, current evidence, particularly from the **Women's Health Initiative (WHI) study**, showed that HRT does not provide primary or secondary cardiovascular protection. - In fact, HRT may increase the risk of **cardiovascular events** like stroke and venous thromboembolism, especially when initiated many years after menopause. *Pyelonephritis* - **Pyelonephritis** is an infection of the kidney, typically caused by bacteria, and is not directly related to menopausal symptoms or hormonal status. - Treatment for pyelonephritis involves **antibiotics** and supportive care, not HRT.
Question 202: Which among the following is not a premalignant lesion of vulva?
- A. Paget's disease
- B. Bacterial Vaginosis (Correct Answer)
- C. Bowen's disease
- D. Lichen Sclerosus
Explanation: ***Bacterial Vaginosis*** - This is a common **vaginal infection** caused by an imbalance of normal vaginal bacteria, characterized by specific symptoms like increased discharge and odor. - Bacterial vaginosis is not considered a premalignant lesion and does not increase the risk of developing vulvar cancer. *Paget's disease* - This is a rare form of intraepithelial adenocarcinoma that can occur on the vulva, presenting as a red, itchy, scaly rash. - While it is a **carcinoma in situ**, it has the potential to become invasive, thus considered a premalignant or pre-invasive condition. *Bowen's disease* - This is a form of **squamous cell carcinoma in situ (SCCIS)**, typically appearing as a slow-growing, red, scaly patch on the skin. - It is considered a premalignant lesion because it can progress to invasive squamous cell carcinoma if left untreated. *Lichen Sclerosus* - This is a chronic inflammatory skin condition primarily affecting the anogenital region, leading to thinning, whitening, and scarring of the skin. - Although it is a benign condition, individuals with vulvar lichen sclerosus have an increased risk (3-5%) of developing **vulvar squamous cell carcinoma**, making it a premalignant condition.
Pharmacology
3 questionsCoagulation testing is needed for:
Amphotericin B acts on:-
Drug which lacks intrinsic activity against anaerobes is:-
NEET-PG 2018 - Pharmacology NEET-PG Practice Questions and MCQs
Question 201: Coagulation testing is needed for:
- A. Lepirudin (direct thrombin inhibitor) (Correct Answer)
- B. Dabigatran (oral anticoagulant)
- C. Enoxaparin (low molecular weight heparin)
- D. Fondaparinux (synthetic pentasaccharide)
Explanation: ***Lepirudin (direct thrombin inhibitor)*** - **Lepirudin**, being a direct thrombin inhibitor, necessitates **coagulation testing** (such as aPTT) to monitor its anticoagulant effect and adjust dosing, especially in patients with renal impairment. - Its narrow therapeutic window and potential for bleeding complications require careful monitoring to ensure patient safety and drug efficacy, as it lacks a specific antidote. *Dabigatran (oral anticoagulant)* - **Dabigatran** is a **direct oral anticoagulant (DOAC)** that typically does not require routine coagulation monitoring due to its predictable pharmacokinetic and pharmacodynamic profiles. - While specific tests can assess its effect in emergencies, they are not part of standard management, distinguishing it from drugs requiring regular monitoring. *Enoxaparin (low molecular weight heparin)* - **Enoxaparin**, a **low molecular weight heparin (LMWH)**, usually does not require routine coagulation monitoring in most patients due to its predictable dose-response relationship. - Monitoring with anti-Xa levels may be considered in specific populations, such as those with renal insufficiency, extremes of weight, or in pediatric and pregnant patients. *Fondaparinux (synthetic pentasaccharide)* - **Fondaparinux** is a synthetic pentasaccharide that **does not require routine coagulation monitoring** as its anticoagulant effect is highly predictable and dose-dependent. - Its action is mediated through selective inhibition of **Factor Xa**, and standard coagulation tests like aPTT or PT are not sensitive to its effects.
Question 202: Amphotericin B acts on:-
- A. Cell membrane (Correct Answer)
- B. Cytoplasm
- C. Nucleus
- D. Cell wall
Explanation: ***Cell membrane*** Amphotericin B primarily targets the **ergosterol** in the fungal **cell membrane** [1]. It binds to **ergosterol**, forming pores and disrupting the membrane's integrity, leading to leakage of cellular contents and ultimately cell death [1]. *Cytoplasm* The cytoplasm is the internal fluid of the cell where many metabolic processes occur, but it is **not the primary target** of amphotericin B's fungicidal action. While cytoplasmic contents leak out due to membrane damage, the drug does not directly act on cytoplasmic components to exert its effect. *Nucleus* The nucleus contains the genetic material of the fungal cell, but amphotericin B does **not directly interact with nuclear components** or DNA. Damage to the cell membrane is the primary mechanism, with nuclear function only indirectly affected by overall cellular disruption. *Cell wall* Fungal cell walls are composed of **chitin and glucans**, but amphotericin B **does not target these components**. Its action is distinct from drugs that inhibit cell wall synthesis, such as echinocandins.
Question 203: Drug which lacks intrinsic activity against anaerobes is:-
- A. Beta lactams
- B. Aminoglycosides (Correct Answer)
- C. Metronidazole
- D. Chloramphenicol
Explanation: ***Aminoglycosides*** - Aminoglycosides require an **oxygen-dependent transport system** to enter bacterial cells and exert their effects. - Due to the **anaerobic environment**, this transport system is inactive, rendering aminoglycosides ineffective against anaerobic bacteria. *Beta lactams* - Many beta-lactam antibiotics, especially certain **cephalosporins (e.g., cefoxitin, cefotetan)** and **carbapenems (e.g., imipenem, meropenem)**, have significant activity against anaerobes. - They inhibit **cell wall synthesis** and are a common choice for infections involving anaerobes. *Metronidazole* - **Metronidazole** is a potent and widely used antibiotic specifically effective against a broad spectrum of **anaerobic bacteria** and protozoa. - It acts by forming **cytotoxic reduced products** that disrupt bacterial DNA synthesis in anaerobic conditions. *Chloramphenicol* - **Chloramphenicol** is a broad-spectrum antibiotic that is highly effective against both aerobic and **anaerobic bacteria**. - It works by binding to the **50S ribosomal subunit**, thereby inhibiting bacterial protein synthesis.
Radiology
1 questionsThe CT thorax image shows:
NEET-PG 2018 - Radiology NEET-PG Practice Questions and MCQs
Question 201: The CT thorax image shows:
- A. Descending aortic dissection
- B. Aortic aneurysm
- C. Ascending aortic dissection (Correct Answer)
- D. Aortic coarctation
Explanation: ***Ascending aortic dissection*** - The CT image shows a **classic intimal flap** separating the true and false lumens in the ascending aorta, which is the hallmark feature of an aortic dissection. - This represents a **Stanford Type A dissection** involving the ascending aorta, which is a life-threatening emergency requiring **immediate surgical intervention** due to high risk of complications including rupture, cardiac tamponade, and acute aortic regurgitation. - The presence of the intimal flap creating two distinct channels (true and false lumens) is pathognomonic for dissection. *Descending aortic dissection* - While the intimal flap is characteristic of dissection, the image specifically shows involvement of the **ascending aorta** (proximal to the left subclavian artery), not the descending thoracic aorta. - Descending aortic dissections (Stanford Type B) are typically managed **medically** with blood pressure control, unlike ascending dissections which require surgery. *Aortic aneurysm* - An **aortic aneurysm** represents focal dilatation of the aortic wall (>50% increase in diameter) without separation of the intimal layers. - While aneurysms can be a risk factor for dissection, the key finding here is the **intimal flap dividing the lumen**, which defines dissection rather than simple aneurysmal dilatation. - The image does not show the uniform circumferential enlargement typical of aneurysms. *Aortic coarctation* - **Aortic coarctation** is a congenital narrowing of the aorta, typically located at the aortic isthmus (near the ligamentum arteriosum), distal to the left subclavian artery. - CT would show focal narrowing with pre-stenotic dilatation and collateral vessel formation, not an intimal flap. - This is a completely different pathology without the characteristic dissection flap seen in this image.
Surgery
1 questionsThe ideal synthetic material used for femoropopliteal bypass when autologous vein is unavailable is:
NEET-PG 2018 - Surgery NEET-PG Practice Questions and MCQs
Question 201: The ideal synthetic material used for femoropopliteal bypass when autologous vein is unavailable is:
- A. Dacron
- B. Xenograft
- C. Saphenous vein
- D. PTFE (non-expanded)
- E. Cryopreserved vein graft
- F. ePTFE (Correct Answer)
- . Polyethylene terephthalate (PET)
- . Allograft
Explanation: ***ePTFE (Expanded Polytetrafluoroethylene)*** - **ePTFE** is the preferred synthetic graft for femoropopliteal bypass when autologous vein is unavailable - Offers good **biocompatibility** and relative resistance to **thrombosis** - Provides superior patency rates in above-knee femoropopliteal bypasses compared to other synthetic materials (5-year patency ~50-60%) - The expanded structure allows tissue ingrowth and better integration *Dacron (Polyethylene terephthalate)* - Generally used for **larger diameter vessels** (e.g., aortoiliac grafts) - Has **inferior patency rates** in smaller diameter femoropopliteal position compared to ePTFE - More prone to kinking and associated with higher rates of intimal hyperplasia in peripheral circulation *Saphenous vein* - The autologous saphenous vein is the **gold standard** for femoropopliteal bypass with superior long-term patency (5-year patency ~70-80%) - However, this question specifically asks for synthetic material when vein is unavailable or unsuitable - Not always available or of adequate quality in all patients *PTFE (non-expanded)* - **Non-expanded PTFE** lacks the porous structure of ePTFE - Not used for vascular grafts due to absence of tissue ingrowth capability - The **expanded** form is specifically engineered for vascular applications