Anesthesiology
1 questionsWhat is the ionized calcium (IC) content of Ringer's lactate in mmol/L, and why is it clinically significant?
NEET-PG 2015 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 541: What is the ionized calcium (IC) content of Ringer's lactate in mmol/L, and why is it clinically significant?
- A. 4 mmol/L (Correct Answer)
- B. 0 mmol/L
- C. 130 mmol/L
- D. 109 mmol/L
Explanation: ***4 mmol/L*** - Ringer's lactate contains **calcium chloride**, contributing to its ionized calcium content of **4 mmol/L**. - This calcium is a critical component for **blood clotting** and **cardiac function**, making it clinically significant, particularly in large volume resuscitation. *130 mmol/L* - This value is close to the **sodium content** of Ringer's lactate, not its ionized calcium. - Sodium is the primary determinant of **fluid balance** and **osmolarity**, distinct from calcium's roles. *109 mmol/L* - This value approximates the **chloride content** of Ringer's lactate, which is important for acid-base balance but not its ionized calcium. - Chloride's primary role is in maintaining **electrical neutrality** and fluid distribution. *0 mmol/L* - Ringer's lactate is a **balanced electrolyte solution** and definitely contains calcium. - A value of 0 would indicate the absence of calcium, which would contradict its formulation and clinical utility, especially in scenarios requiring **electrolyte repletion**.
Internal Medicine
1 questionsWhich of the following is a cause of post-transplantation hypertension? I. Rejection II. Cyclosporine nephrotoxicity III. Renal transplant artery stenosis (RTAS) IV. Recurrent disease in the allograft. Select the correct option.
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 541: Which of the following is a cause of post-transplantation hypertension? I. Rejection II. Cyclosporine nephrotoxicity III. Renal transplant artery stenosis (RTAS) IV. Recurrent disease in the allograft. Select the correct option.
- A. None of the above are correct causes.
- B. I, II, and IV are correct causes.
- C. I and III are correct causes.
- D. All of the options are correct causes of post-transplantation hypertension. (Correct Answer)
Explanation: ***All of the options are correct causes of post-transplantation hypertension.*** - Post-transplantation hypertension often has a multifactorial etiology, with **rejection**, **cyclosporine nephrotoxicity**, **renal transplant artery stenosis (RTAS)**, and **recurrent disease in the allograft** all being significant contributors. - Each of these conditions can lead to mechanisms that elevate blood pressure, such as **renal ischemia**, activation of the **renin-angiotensin system**, and inflammatory responses affecting renal function. *I, II, and IV are correct causes.* - This option is incorrect because it excludes **renal transplant artery stenosis (RTAS)** (III), which is a well-established cause of secondary hypertension in transplant recipients due to reduced blood flow to the allograft. - **RTAS** activates the renin-angiotensin-aldosterone system (RAAS), leading to **vasoconstriction** and **sodium retention**, contributing to hypertension. *I and III are correct causes.* - This option is incorrect as it omits other crucial causes like **cyclosporine nephrotoxicity** (II) and **recurrent disease in the allograft** (IV), both of which are documented contributors to post-transplantation hypertension. - **Cyclosporine nephrotoxicity** causes afferent arteriolar vasoconstriction and glomerulosclerosis, directly increasing blood pressure. *None of the above are correct causes.* - This option is incorrect because **rejection**, **cyclosporine nephrotoxicity**, **renal transplant artery stenosis (RTAS)**, and **recurrent disease in the allograft** are all recognized and significant causes of post-transplantation hypertension. - Each condition has distinct pathological mechanisms that contribute to **elevated blood pressure** in transplant recipients.
Pharmacology
7 questionsWhat is the best method for treating methanol poisoning?
Interstitial nephritis is associated with all of the following medications except:
What is the classification of Lorcaserin?
What is the half-life of nicotine in blood?
Flu-like symptoms are a side effect of which anti-TB drug?
All of the following are known adverse effects of thalidomide, except:
Where does the oxidation of drugs mainly take place?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 541: What is the best method for treating methanol poisoning?
- A. Calcium gluconate
- B. BAL
- C. Fomepizole (Correct Answer)
- D. Deferoxamine
Explanation: ***Fomepizole*** - **Fomepizole** (Antizol) is a potent inhibitor of **alcohol dehydrogenase**, the enzyme responsible for metabolizing methanol into toxic metabolites like formic acid [1]. - By inhibiting this enzyme, fomepizole prevents the formation of these harmful metabolites, thus halting the progression of methanol toxicity and reducing mortality [1]. - It is the **gold standard** antidote for methanol poisoning. *Calcium gluconate* - **Calcium gluconate** is primarily used to treat **hypocalcemia** and magnesium toxicity. - It has no role in the direct treatment or detoxification of methanol poisoning. *Deferoxamine* - **Deferoxamine** is a **chelating agent** used to treat **iron toxicity** by binding to iron and facilitating its excretion [3]. - It is not effective for methanol poisoning as it does not interact with methanol or its toxic metabolites. *BAL* - **BAL** (British Anti-Lewisite, dimercaprol) is a chelating agent primarily used for poisoning by **heavy metals** such as arsenic, mercury, and gold [2]. - It has no therapeutic role in methanol poisoning, which involves a different toxicological mechanism.
Question 542: Interstitial nephritis is associated with all of the following medications except:
- A. INH (Correct Answer)
- B. Diuretics
- C. Allopurinol
- D. Beta-lactam antibiotics
Explanation: ***INH*** - **Isoniazid (INH)** is primarily associated with **hepatotoxicity** (liver damage) and **peripheral neuropathy**, not typically interstitial nephritis. - While many drugs can rarely cause various adverse effects, INH is not a recognized common cause of **drug-induced interstitial nephritis**. *Beta-lactam antibiotics* - **Beta-lactam antibiotics**, including penicillins and cephalosporins, are among the most common causes of **drug-induced acute interstitial nephritis (AIN)**. - AIN is an **allergic hypersensitivity reaction** characterized by inflammation of the kidney's tubules and interstitium. *Diuretics* - Certain **diuretics**, particularly **thiazide diuretics** and **loop diuretics**, have been implicated in causing **acute interstitial nephritis**. - The mechanism is thought to be an **allergic or hypersensitivity reaction** within the renal tubules and interstitium. *Allopurinol* - **Allopurinol**, used to treat gout and hyperuricemia, is a known cause of **drug-induced acute interstitial nephritis**. - Renal involvement with allopurinol can range from mild tubular dysfunction to severe **acute kidney injury** due to AIN.
Question 543: What is the classification of Lorcaserin?
- A. Anti-anxiety
- B. Anti-smoking
- C. Anti-helminthic
- D. Anti-obesity (Correct Answer)
Explanation: ***Anti-obesity*** - Lorcaserin is a selective **serotonin 5-HT₂C receptor agonist** that works by promoting satiety and reducing food intake. - It is prescribed as a long-term treatment for **weight management** in adults who are obese or overweight with at least one weight-related comorbidity. *Anti-anxiety* - Anti-anxiety medications, such as **benzodiazepines** or **SSRIs**, primarily target neurotransmitters like GABA or serotonin 5-HT₁A receptors to reduce anxiety symptoms. - Lorcaserin's primary mechanism of action is distinct, focusing on the 5-HT₂C receptor for appetite regulation, not anxiety. *Anti-smoking* - Anti-smoking medications, like **varenicline** or **bupropion**, are designed to reduce nicotine cravings and withdrawal symptoms. - Their mechanisms often involve nicotinic acetylcholine receptors or dopamine and norepinephrine reuptake inhibition, which differs from lorcaserin's action. *Anti-helminthic* - Anti-helminthic drugs are used to treat **parasitic worm infections** by paralyzing or killing the worms. - Common examples include **albendazole** or **mebendazole**, which have no relation to appetite control or obesity treatment.
Question 544: What is the half-life of nicotine in blood?
- A. 2 hours (Correct Answer)
- B. 15 minutes
- C. 5 hours
- D. 24 hours
Explanation: ***2 hours*** - Nicotine has a **relatively short half-life** in the blood, typically around 2 hours, contributing to frequent dosing in tobacco users. - This rapid elimination means that nicotine concentrations decrease significantly within a few hours after the last dose, leading to **withdrawal symptoms** or cravings. *15 minutes* - A 15-minute half-life would imply an **extremely rapid clearance**, which is not characteristic of nicotine. - Such quick elimination would make it very difficult to maintain consistent drug levels and would lead to immediate, intense withdrawal. *5 hours* - While longer than the actual half-life, 5 hours is still within the realm of substances requiring **multiple daily doses**. - However, it would mean nicotine levels would remain elevated for a longer period than observed, potentially delaying withdrawal. *24 hours* - A 24-hour half-life would mean nicotine would accumulate significantly in the body with daily use, leading to **prolonged effects** and a much slower decline in concentrations after cessation. - This half-life is typical for drugs designed for **once-daily dosing**, which is not the case for nicotine.
Question 545: Flu-like symptoms are a side effect of which anti-TB drug?
- A. Rifampicin (Correct Answer)
- B. Isoniazid
- C. Pyrazinamide
- D. Ethambutol
Explanation: ***Rifampicin*** - **Flu-like syndrome** (fever, chills, myalgia, and headache) is a dose-dependent side effect of **rifampicin**, particularly with intermittent dosing. - This reaction is due to **immunological mechanisms**, involving antibodies against rifampicin. *Isoniazid* - The most significant side effect of isoniazid is **hepatotoxicity**, which can range from mild elevated liver enzymes to severe hepatitis. - It can also cause **peripheral neuropathy**, particularly in malnourished patients or those with risk factors, preventable with pyridoxine (vitamin B6) supplementation. *Pyrazinamide* - **Hepatotoxicity** is a major concern with pyrazinamide, often leading to elevated liver enzymes and, in some cases, severe liver damage. - It frequently causes **hyperuricemia**, which can precipitate acute gouty arthritis due to decreased excretion of uric acid. *Ethambutol* - The most characteristic adverse effect of ethambutol is **optic neuritis**, causing decreased visual acuity, red-green color blindness, and visual field defects. - Regular **ophthalmological monitoring** is crucial during treatment to detect this reversible side effect early.
Question 546: All of the following are known adverse effects of thalidomide, except:
- A. DVT
- B. Neuropathy
- C. Teratogenicity
- D. Diarrhoea (Correct Answer)
Explanation: ***Diarrhoea*** - **Diarrhoea** is generally *not* considered a common or significant adverse effect of thalidomide. Constipation is more frequently reported. - While individual reactions vary, thalidomide's primary adverse effect profile does not typically include diarrhoea. *Teratogenicity* - **Teratogenicity** is the most notorious adverse effect of thalidomide, causing severe birth defects like **phocomelia** (shortened or absent limbs) in infants exposed during pregnancy. - Due to this, stringent **risk evaluation and mitigation strategies (REMS)** are in place for thalidomide use. *DVT* - Thalidomide is known to increase the risk of **venous thromboembolism (VTE)**, including **deep vein thrombosis (DVT)** and pulmonary embolism, especially in patients with multiple myeloma. - Prophylactic anticoagulation is often recommended for patients receiving thalidomide, particularly in combination with corticosteroids. *Neuropathy* - **Peripheral neuropathy** is a common and dose-limiting adverse effect of thalidomide, often presenting as numbness, tingling, and pain in the hands and feet. - It can be progressive and potentially irreversible, requiring careful monitoring and dose adjustments.
Question 547: Where does the oxidation of drugs mainly take place?
- A. Smooth ER (Correct Answer)
- B. Rough ER
- C. Cytoplasm
- D. Nucleus
Explanation: **Smooth ER** - The **smooth endoplasmic reticulum (SER)** is rich in enzymes, particularly the **cytochrome P450 system**, which is primarily responsible for phase I **oxidation reactions** of many drugs and xenobiotics [1]. - These oxidative reactions typically **increase the polarity** of drugs, making them easier to excrete [1]. *Nucleus* - The nucleus primarily contains the cell's **genetic material** (DNA) and is involved in **gene expression** and replication. - It does not contain the necessary enzymatic machinery for the major oxidative metabolism of drugs. *Rough ER* - The **rough endoplasmic reticulum (RER)** is characterized by the presence of **ribosomes** and is mainly involved in the **synthesis, folding, modification, and transport of proteins** destined for secretion or insertion into membranes [2]. - While it plays a role in protein synthesis, it is not the primary site for drug oxidation. *Cytoplasm* - The cytoplasm contains various organelles and is the site of many metabolic pathways, including **glycolysis** and some **phase II drug metabolism** (e.g., glucuronidation, sulfation) [1]. - However, the bulk of phase I **oxidative drug metabolism** does not occur in the general cytoplasm but rather within the smooth ER due to the concentration of relevant enzymes there [1].
Physiology
1 questionsLower esophageal sphincter pressure is increased by all of the following substances, EXCEPT:
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 541: Lower esophageal sphincter pressure is increased by all of the following substances, EXCEPT:
- A. Motilin
- B. Gastrin
- C. Substance P
- D. Secretin (Correct Answer)
Explanation: ***Secretin*** - **Secretin** is a gastrointestinal hormone that *decreases* lower esophageal sphincter (LES) pressure - This hormone is released from S cells in the duodenum in response to acidic chyme - Its primary role is to stimulate the pancreas to release **bicarbonate-rich fluid** to neutralize acidic chyme entering the duodenum - By decreasing LES pressure, it facilitates the passage of gastric contents into the duodenum during digestion *Gastrin* - **Gastrin** is a hormone that *increases* lower esophageal sphincter (LES) pressure - This helps prevent gastroesophageal reflux when the stomach is distended - It also stimulates the secretion of **gastric acid** by parietal cells in the stomach - Released from G cells in the gastric antrum in response to protein ingestion *Motilin* - **Motilin** is a peptide hormone that *increases* lower esophageal sphincter (LES) pressure - It initiates the **migrating motor complex (MMC)** during the interdigestive period - Stimulates gastric and intestinal motility - Released from M cells in the duodenum and jejunum *Substance P* - **Substance P** is a neuropeptide that *increases* lower esophageal sphincter (LES) pressure - Functions as both a neurotransmitter and neuromodulator in the enteric nervous system - Plays a role in **smooth muscle contraction** and gastrointestinal motility - Also involved in pain transmission and inflammatory responses