Anesthesiology
3 questionsCocaine was first used as a local anesthetic by?
What is the critical temperature of Nitrous Oxide (N2O)?
Which of the following is NOT a contraindication for spinal anaesthesia?
NEET-PG 2012 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 1081: Cocaine was first used as a local anesthetic by?
- A. Holmer Wells
- B. Morton
- C. Carl Koller (Correct Answer)
- D. None of the options
Explanation: ***Carl Koller*** - **Carl Koller** (1857-1944), an Austrian ophthalmologist, is credited with the first clinical use of cocaine as a local anesthetic in 1884. - He demonstrated its efficacy for topical anesthesia in eye surgery, revolutionizing surgical practices. *Holmer Wells* - **Horace Wells** (not Holmer) was an American dentist who pioneered the use of **nitrous oxide** as an anesthetic in dentistry in the 1840s, preceding Koller's work with cocaine. - His contributions were focused on general anesthesia for pain relief during tooth extractions. *Morton* - **William T.G. Morton** was another American dentist who famously demonstrated the use of **ether** as a surgical anesthetic in 1846. - His work popularized surgical anesthesia, but it was not related to cocaine as a local anesthetic. *None of the options* - This option is incorrect because Carl Koller is historically recognized as the pioneer for the clinical use of **cocaine as a local anesthetic**.
Question 1082: What is the critical temperature of Nitrous Oxide (N2O)?
- A. -118°C
- B. -36°C
- C. -30°C
- D. -36.5°C (Correct Answer)
Explanation: **-36.5°C** - The **critical temperature** of **nitrous oxide (N2O)** is **36.5°C**, which is the temperature above which it cannot be liquefied by pressure alone. - This value is important for understanding the **physical state** and safe handling of N2O, as deviations can lead to phase changes or storage issues. *-118°C* - This temperature is significantly lower than the actual critical temperature of N2O and is incorrect. - This value might be related to the **boiling point of other gases** but not the critical temperature of N2O. *-36°C* - While close, **-36°C** is not the precise critical temperature for nitrous oxide. - This small difference can be significant in contexts requiring **exact physical properties** of gases. *-30°C* - This temperature is incorrect and is higher than the actual critical temperature of N2O. - At this temperature, N2O would still behave as a **liquefiable gas** under sufficient pressure, indicating it is below its critical point.
Question 1083: Which of the following is NOT a contraindication for spinal anaesthesia?
- A. Raised intracranial tension
- B. Bleeding disorder
- C. Hypertension (Correct Answer)
- D. Infection at injection site
Explanation: ***Hypertension*** - While **severe uncontrolled hypertension** may necessitate blood pressure stabilization before surgery, **mild to moderate hypertension** is not an absolute contraindication for spinal anesthesia. - In fact, spinal anesthesia can sometimes be beneficial in hypertensive patients due to its **vasodilatory effects**, which may help lower blood pressure. *Bleeding disorder* - A **bleeding disorder** (e.g., thrombocytopenia, coagulopathy) is a **major contraindication** due to the high risk of **epidural or spinal hematoma** formation. - A hematoma can lead to **spinal cord compression** and irreversible neurological damage. *Raised intracranial tension* - **Raised intracranial tension (ICT)** is a **strict contraindication** because the drop in cerebrospinal fluid (CSF) pressure during spinal anesthesia can worsen the pressure gradient across the foramen magnum. - This can precipitate **herniation of the brainstem** and lead to catastrophic neurological injury or death. *Infection at injection site* - The presence of an **infection at the injection site** is an absolute contraindication as it poses a significant risk of introducing bacteria into the **subarachnoid space**. - This can lead to serious complications such as **meningitis** or a **spinal abscess**.
Pharmacology
2 questionsWhich of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?
What is the effect of adding epinephrine to lignocaine (a local anesthetic)?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 1081: Which of the following is the prototypical sympathomimetic agent with both alpha and beta-adrenergic activity?
- A. Epinephrine (Correct Answer)
- B. Isoproterenol
- C. Norepinephrine
- D. Dopamine
Explanation: ***Epinephrine*** - Epinephrine (adrenaline) is a potent direct-acting **sympathomimetic** that stimulates both **alpha and beta-adrenergic receptors**. - Its diverse effects on the cardiovascular, respiratory, and other systems make it the prototypical agent for demonstrating both receptor activities. *Norepinephrine* - While norepinephrine (noradrenaline) also acts on **alpha and beta-1 receptors**, its affinity for **beta-2 receptors** is significantly lower than epinephrine. - This results in a predominant effect on **vasoconstriction** and cardiac contractility rather than bronchodilation or peripheral vasodilation. *Isoproterenol* - Isoproterenol is a **non-selective beta-adrenergic agonist**, meaning it primarily stimulates **beta-1 and beta-2 receptors**. - It has minimal or no activity at **alpha-adrenergic receptors**, differentiating it from epinephrine's mixed activity. *Dopamine* - Dopamine's effects are **dose-dependent**; at low doses, it primarily stimulates **dopamine receptors** and at moderate doses, it activates **beta-1 receptors**. - At high doses, it can stimulate **alpha-adrenergic receptors**, but its primary and distinguishing characteristic is its agonism at **dopamine receptors**, which epinephrine does not share.
Question 1082: What is the effect of adding epinephrine to lignocaine (a local anesthetic)?
- A. Increases distribution of local anesthetic
- B. Decreases absorption of local anesthetic (Correct Answer)
- C. Decreases duration of local anesthetic
- D. Increases metabolism of local anesthetic
Explanation: ***Decreases absorption of local anesthetic*** - Epinephrine causes **vasoconstriction** at the site of injection, which reduces the rate at which the local anesthetic is absorbed into the systemic circulation. - This slower absorption leads to a **higher concentration of the anesthetic** at the nerve fibers, prolonging its effect and reducing systemic toxicity. - This is the primary mechanism by which epinephrine enhances local anesthetic efficacy. *Increases distribution of local anesthetic* - The primary effect of epinephrine is to **localize the anesthetic** by reducing its systemic distribution. - This localization is achieved through **vasoconstriction**, which keeps the drug at the desired site rather than allowing it to distribute widely. *Decreases duration of local anesthetic* - By slowing absorption, epinephrine effectively **increases the duration of action** of the local anesthetic. - The anesthetic remains at the site of action for a longer period, providing **extended pain relief**. *Increases metabolism of local anesthetic* - Epinephrine does not directly affect the **metabolic rate** of local anesthetics. - The primary mechanism of metabolism for amides like lignocaine is in the **liver** by cytochrome P450 enzymes.
Radiology
5 questionsThe most appropriate first-line imaging modality to detect adrenal metastasis due to bronchogenic carcinoma is:
Which of the following conditions characteristically causes bilateral hypertranslucency of lung fields on chest X-ray?
Which of the following is not typically seen on a chest X-ray in pulmonary artery hypertension?
Investigation of choice for intramedullary SOL is -
Popcorn calcification is seen in:
NEET-PG 2012 - Radiology NEET-PG Practice Questions and MCQs
Question 1081: The most appropriate first-line imaging modality to detect adrenal metastasis due to bronchogenic carcinoma is:
- A. PET scan
- B. MRI of the abdomen
- C. Adrenal radionuclide scan
- D. Contrast Enhanced CT abdomen (Correct Answer)
Explanation: **Contrast Enhanced CT abdomen** - **Contrast-enhanced CT abdomen** is generally considered the most sensitive and cost-effective imaging modality for detecting **adrenal metastases**. - It allows for detailed visualization of adrenal gland morphology, including size, shape, and enhancement patterns, which can help differentiate benign from malignant lesions. *PET scan* - While **PET (Positron Emission Tomography) scans** are highly sensitive for detecting metabolically active metastatic disease, they are often used as a secondary imaging modality to characterize indeterminate lesions found on CT or MRI. - **PET scans** can have false positives in benign adrenal tumors (e.g., adenomas rich in fat) and are less readily available or higher in cost for initial screening compared to CT. *MRI of the abdomen* - **MRI of the abdomen** can be very useful for further characterization of adrenal masses, especially for distinguishing between lipid-rich adenomas and metastases. - However, for initial detection, especially in the context of screening for distant metastases from bronchogenic carcinoma, **CT is generally preferred due to its wider availability, speed, and lower cost**. *Adrenal radionuclide scan* - **Adrenal radionuclide scans** (e.g., using MIBG or iodocholesterol) are primarily used for functional imaging of adrenal glands, typically to detect specific types of tumors like pheochromocytomas or aldosteronomas. - These scans are **not sensitive for detecting adrenal metastases** from bronchogenic carcinoma, as the metastatic lesions do not typically exhibit the specific uptake patterns targeted by these radiotracers.
Question 1082: Which of the following conditions characteristically causes bilateral hypertranslucency of lung fields on chest X-ray?
- A. Mcleod syndrome
- B. Poland syndrome
- C. Emphysema (Correct Answer)
- D. Pneumothorax
Explanation: ***Correct: Emphysema*** - **Emphysema** causes destruction of alveolar walls, leading to enlarged air spaces and **air trapping**, making both lungs appear hypertranslucent on X-ray - This **bilateral hypertranslucency** is due to reduced lung tissue density, decreased vascular markings, and increased air volume - Classic radiographic features include flattened diaphragms, increased retrosternal space, and hyperlucent lung fields *Incorrect: Mcleod syndrome* - Also known as **Swyer–James–MacLeod syndrome**, this condition causes **unilateral** lung or lobe hyperlucency due to post-infectious obliterative bronchiolitis - The key differentiating feature is that it's **unilateral**, whereas the question asks for bilateral hypertranslucency - Affected lung shows air trapping on expiratory films *Incorrect: Pneumothorax* - A **pneumothorax** presents as a **unilateral** or focal hypertranslucent area due to air in the pleural space - Characterized by **absence of lung markings** beyond the visceral pleural line and associated lung collapse - This is a pleural space abnormality, not a bilateral parenchymal lung disease *Incorrect: Poland syndrome* - **Poland syndrome** is a congenital condition with absence or underdevelopment of the pectoralis major muscle - Can lead to **unilateral** apparent hyperlucency on the affected side due to missing chest wall muscle - This is a **chest wall anomaly**, not a parenchymal lung disease causing bilateral hypertranslucency
Question 1083: Which of the following is not typically seen on a chest X-ray in pulmonary artery hypertension?
- A. Enlargement of central arteries
- B. Peripheral pruning
- C. Narrowing of central arteries (Correct Answer)
- D. None of the options
Explanation: ***Narrowing of central arteries*** - **Pulmonary artery hypertension** is characterized by the **enlargement of the central pulmonary arteries** due to increased pressure. - **Narrowing of central arteries** would contradict the hemodynamic changes seen in pulmonary hypertension. - This is the finding that is **NOT typically seen**, making this the correct answer. *Enlargement of central arteries* - This is a **hallmark radiographic finding** in pulmonary hypertension, reflecting the **dilatation of the main and proximal pulmonary arteries** due to increased pressure. - The **pulmonary artery segment becomes prominent**, often appearing convex on the left heart border. *Peripheral pruning* - This refers to the **abrupt tapering and loss of peripheral pulmonary vascular markings**, indicating reduced blood flow to the distal lung parenchyma. - It is a **common finding in advanced pulmonary hypertension**, as the distal vessels constrict and become obliterated. *None of the options* - This is incorrect since **narrowing of central arteries** is clearly not a typical finding in pulmonary hypertension.
Question 1084: Investigation of choice for intramedullary SOL is -
- A. MRI (Correct Answer)
- B. USG
- C. CT
- D. X-ray
Explanation: ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice for intramedullary lesions due to its superior **soft tissue contrast** and ability to visualize the **spinal cord** parenchyma. - It provides detailed information on lesion size, location, and internal characteristics, which is crucial for diagnosis and surgical planning. *USG* - **Ultrasound (USG)** has limited utility for intramedullary lesions as a primary diagnostic tool because **bone impedes sound waves**, making it difficult to visualize structures within the spinal canal. - It might be used for neonatal spinal screening or intraoperative guidance, but not for definitive diagnosis of intramedullary lesions in adults. *CT* - **Computed Tomography (CT)** excels at visualizing **bone structures** and calcifications, but it provides less detailed information about soft tissue elements like the spinal cord compared to MRI. - While it can identify bony changes associated with intramedullary lesions, it is not the preferred initial imaging modality for characterizing the lesion itself. *X-ray* - **X-rays** provide basic imaging of bone but offer essentially **no visualization of soft tissues** such as the spinal cord or intramedullary lesions. - They are primarily used to identify gross bony abnormalities like fractures or severe degenerative changes, not for subtle intraspinal pathologies.
Question 1085: Popcorn calcification is seen in:
- A. Pulmonary hamartoma (Correct Answer)
- B. Bronchogenic carcinoma
- C. Tuberculosis
- D. Pulmonary metastases
Explanation: ***Pulmonary hamartoma*** - **Popcorn calcification** is a pathognomonic radiographic finding highly suggestive of **pulmonary hamartoma**, a **benign tumor** composed of cartilage, fat, and connective tissue - This characteristic calcification pattern is due to the presence of **chondroid (cartilaginous) tissue** within the lesion - Appears as coarse, irregular calcifications resembling popcorn on chest X-ray or CT scan *Bronchogenic carcinoma* - Malignant lung lesions typically show **irregular, spiculated, or ill-defined margins** and tend to grow rapidly - While calcification can occur in some lung malignancies, it usually appears as **eccentric, stippled, or amorphous** rather than the distinctive popcorn pattern - Popcorn calcification is not a feature of primary lung cancers *Tuberculosis* - **Granulomatous infections** such as tuberculosis often lead to calcification, but it usually presents as **laminated, clustered, or target-like patterns** in lymph nodes or within granulomas (Ghon lesion, Ranke complex) - **Popcorn calcification** is not a typical feature of active or healed tuberculous lesions *Pulmonary metastases* - **Metastatic lesions** are generally not calcified, although a few primary tumors (e.g., mucinous adenocarcinoma, osteosarcoma, chondrosarcoma) can metastasize as calcified nodules - When calcification is present in metastases, it is rarely in the specific **popcorn pattern** and is usually diffuse, punctate, or amorphous