NEET-PG 2013 Practice Questions

Q: What is the most appropriate initial management for paralysis resulting from organophosphorus poisoning?

Supportive care, including respiratory support. **Supportive care, including respiratory support** * **Paralysis** in organophosphorus poisoning (OPP) is often due to **nicotinic effects** at the neuromuscular junction, leading to respiratory muscle weakness and failure [2]. * **Respiratory support** through mechanical ventilation is crucial to maintain oxygenation and prevent complications while awaiting the effects of antidotal therapy [1], [2]. * *Atropine to counteract muscarinic symptoms* * **Atropine** primarily blocks **muscarinic receptors**, effectively treating symptoms like bradycardia, bronchorrhea, and miosis [2]. * It does **not reverse the nicotinic effects** responsible for muscle paralysis and respiratory failure. * *Oximes to reactivate acetylcholinesterase* * **Oximes (e.g., pralidoxime)** reactivate **acetylcholinesterase**, thereby addressing the underlying cause of acetylcholine accumulation [2]. * They are most effective if given **early** before irreversible aging of the enzyme occurs, but their effect on established paralysis can be limited without concurrent respiratory support [2]. * *No specific antidote* * This statement is incorrect; **atropine** and **oximes** are specific antidotes for organophosphorus poisoning [2]. * While these antidotes are vital, initial management prioritizing **airway and breathing support** is paramount due to the life-threatening respiratory paralysis [1].

Q: Which of the following glands is NOT typically involved in Multiple Endocrine Neoplasia type II A (MEN II A)?

Pituitary gland. ***Pituitary gland*** - The **pituitary gland** is not a characteristic component of **MEN II A**. It is, however, associated with **Multiple Endocrine Neoplasia type I (MEN I)**, which involves the 3 Ps: **pituitary**, **parathyroid**, and **pancreas** [1]. - **MEN IIA** classically involves **medullary thyroid carcinoma**, **pheochromocytoma**, and **parathyroid hyperplasia** [1]. *Thyroid gland* - The **thyroid gland** is centrally involved in MEN IIA, specifically through the development of **medullary thyroid carcinoma (MTC)**, a hallmark feature. - MTC arises from the parafollicular C cells of the thyroid and secretes **calcitonin**. *Parathyroid gland* - The **parathyroid gland** is often involved in MEN IIA, typically presenting as **parathyroid hyperplasia** or adenoma, leading to **primary hyperparathyroidism**. - This typically results in elevated **parathyroid hormone** levels and **hypercalcemia**. *Adrenal gland* - The **adrenal gland** is a key player in MEN IIA due to the occurrence of **pheochromocytoma**, a tumor of the adrenal medulla. - Pheochromocytomas can be bilateral and secrete **catecholamines**, leading to hypertension and other symptoms.

Q: Which of the following statements is false regarding hereditary spherocytosis?

Decreased MCHC. ***Decreased MCHC*** - Hereditary spherocytosis typically presents with an **increased MCHC** due to the spherocytes being more concentrated. - MCHC is a measure of the hemoglobin concentration in red blood cells, and in spherocytosis, this value is often elevated rather than decreased. *Defect in ankyrin* - This is a true statement; hereditary spherocytosis is associated with a defect in **ankyrin**, a protein that helps maintain the cell's membrane structure [2]. - Mutations in ankyrin lead to instability of the red blood cell membrane, resulting in spherocyte formation [2]. *Decreased MCV* - In hereditary spherocytosis, MCV is often **normal or slightly increased**, as it reflects the volume of red blood cells, which can be misinterpreted due to the presence of spherocytes. - Spherocytes are smaller cells, which can mistakenly suggest a falsely decreased MCV if not properly interpreted [1]. *Reticulocytosis* - This condition typically presents with **reticulocytosis** as a response to hemolysis, indicating the bone marrow is producing more red blood cells to compensate [1]. - The presence of reticulocytosis is a common finding in hereditary spherocytosis due to increased destruction of spherocytes. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641.

Q: Intracorpuscular hemolytic anemia is seen in ?

Thalassemia. ***Thalassemia*** - Thalassemia is characterized by **intracorpuscular hemolysis** due to defective hemoglobin synthesis, leading to premature destruction of red blood cells [1][2]. - It manifests as **microcytic anemia** with associated **extramedullary erythropoiesis** in severe cases [1]. *Autoimmune hemolytic anemia* - This condition leads to **extravascular hemolysis**, primarily affecting red blood cells in the spleen, not within the plasma [2]. - It is often associated with **positive direct Coombs test**, indicating reactants on the RBC surface. *TIP* - TIP (Thrombotic Microangiopathy) primarily involves **microangiopathic hemolytic anemia** and is not classified as intracorpuscular [2]. - The hemolysis in TIP occurs due to **microthrombi**, causing damage to red blood cells as they pass through narrowed vessels. *Infection* - Infections can lead to **hemolysis**, but this is typically **extravascular** due to splenic clearance or due to other mechanisms like **malaria** [2]. - The hemolytic mechanism is not intracorpuscular, as seen in conditions like thalassemia. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 596-597.

Q: Muscarinic cholinergic receptors are seen at all sites, except?

Neuromuscular junction. ***Neuromuscular junction*** - The **neuromuscular junction** primarily contains **nicotinic cholinergic receptors**, not muscarinic receptors. - Activation of these nicotinic receptors by acetylcholine causes muscle contraction. *Stomach* - The stomach contains **muscarinic M3 receptors** which mediate gastric acid secretion and smooth muscle contraction. - Activation by acetylcholine via the vagus nerve promotes digestion. *CNS* - The **central nervous system** has various subtypes of **muscarinic receptors (M1-M5)** distributed throughout, playing roles in learning, memory, and motor control. - These receptors modulate neuronal excitability and neurotransmitter release. *Glands* - Most exocrine glands (e.g., salivary, lacrimal, sweat glands) are richly supplied with **muscarinic receptors**, primarily **M3**. - Activation leads to increased glandular secretion.

Q: Which urinary bladder spasmolytic has local anesthetic properties?

Oxybutynin. ***Oxybutynin*** - Possesses both **anticholinergic properties** (bladder smooth muscle relaxation) and **direct local anesthetic properties**, which contribute to its spasmolytic effect on the detrusor muscle. - The **local anesthetic action** directly reduces bladder detrusor muscle contractions, explaining its efficacy in treating urge incontinence and overactive bladder. - This dual mechanism makes it unique among bladder spasmolytics. *Tamsulosin* - Is an **alpha-1 adrenergic receptor blocker** used for benign prostatic hyperplasia (BPH) by relaxing smooth muscle in the prostate and bladder neck. - Does **not have local anesthetic properties** and is not a bladder detrusor spasmolytic. *Terazosin* - Also an **alpha-1 adrenergic receptor blocker**, similar to tamsulosin, used for BPH and hypertension. - Acts via **vascular and prostatic smooth muscle relaxation**, without local anesthetic or bladder spasmolytic effects. *Yohimbine* - Is an **alpha-2 adrenergic receptor antagonist** known for increasing sympathetic outflow. - Does **not have bladder spasmolytic effects** or local anesthetic properties.

Q: Which of the following is classified as an antispasmodic agent?

Dicyclomine. ***Dicyclomine*** - **Dicyclomine** is an **anticholinergic** medication that works by blocking muscarinic receptors, thereby reducing smooth muscle spasm in the gastrointestinal tract. - It is commonly used to treat symptoms of **irritable bowel syndrome (IBS)**, such as abdominal pain and cramping. *Physostigmine* - **Physostigmine** is a **cholinesterase inhibitor** that increases the concentration of acetylcholine at the synaptic cleft. - It is used to treat **anticholinergic poisoning** by reversing the effects of anticholinergic drugs, rather than acting as an antispasmodic itself. *Tropicamide* - **Tropicamide** is an **anticholinergic** agent primarily used as a **mydriatic** (pupil dilator) and **cycloplegic** (paralyzes the ciliary muscle) for ophthalmic examinations. - Its action is localized to the eye and it does not have significant systemic antispasmodic effects. *None of the options* - This option is incorrect because one of the listed medications is indeed classified as an antispasmodic agent. - When "None of the options" appears as a choice, it should only be selected if all other options are clearly incorrect.

Q: Besides its properties of decreasing intraocular pressure, timolol is preferred in the treatment of glaucoma because it

Produces no miosis. ***Produces no miosis*** - Timolol, a **non-selective beta-blocker**, decreases intraocular pressure without affecting pupillary size. - This is a **key advantage** in glaucoma treatment as miosis (pupil constriction) can worsen vision, especially in patients with cataracts. - Unlike **miotics** (e.g., pilocarpine), timolol does not cause pupillary constriction, making it better tolerated. *Possesses membrane stabilizing activity* - While some beta-blockers possess **membrane-stabilizing activity** (local anesthetic effect), this property is not a primary reason for timolol's preference in glaucoma. - This action is more relevant in antiarrhythmic uses of beta-blockers due to its effect on cardiac action potentials. *Increases outflow of aqueous humor* - Timolol primarily reduces intraocular pressure by **decreasing the production of aqueous humor**, not by increasing its outflow. - Drugs like **pilocarpine** (a cholinergic agonist) or **prostaglandin analogs** increase outflow. *Is a selective beta-adrenoceptor blocker* - Timolol is a **non-selective beta-blocker**, meaning it blocks both beta-1 and beta-2 adrenergic receptors. - Its non-selectivity is associated with systemic side effects (e.g., bronchospasm, bradycardia), and selective beta-blockers like **betaxolol** exist but are not the primary reason for timolol's preference in glaucoma.

Q: Which of the following is not a recognized use of alpha-2-agonists?

Benign Hyperplasia of prostate. ***Correct Answer: Benign Hyperplasia of prostate*** - Alpha-2-agonists are **NOT** used to treat **benign prostatic hyperplasia (BPH)**; this condition is typically managed with **alpha-1-blockers** (e.g., tamsulosin, alfuzosin) or 5-alpha-reductase inhibitors. - Alpha-1-blockers relax the smooth muscle in the prostate and bladder neck, improving urine flow, which involves a different receptor mechanism than alpha-2-agonists. - Alpha-2-agonists would not provide therapeutic benefit for BPH. *Incorrect: Glaucoma* - Alpha-2-agonists (e.g., **brimonidine**, **apraclonidine**) **are** used to treat **glaucoma** by reducing aqueous humor production and increasing uveoscleral outflow. - This action helps to **lower intraocular pressure**, a primary goal in glaucoma management. *Incorrect: Hypertension* - Central-acting alpha-2-agonists (e.g., **clonidine**, **methyldopa**) **are** used as **antihypertensive agents**. - They reduce sympathetic outflow from the central nervous system, leading to decreased heart rate, vasodilation, and consequently, **lower blood pressure**. *Incorrect: Sedation* - Alpha-2-agonists like **dexmedetomidine** and **clonidine** **are** commonly used for **sedation** in critically ill patients, especially in intensive care units. - They produce sedation, analgesia, and anxiolysis without causing significant respiratory depression, making them valuable in certain clinical settings.

Q: Which of the following factors influences the duration of action of a drug?

All of the options. ***All of the options*** - **Clearance** and **rate of elimination** are the primary determinants of how long a drug stays in the body at therapeutic levels, thus directly influencing its duration of action. - **Bioavailability** affects the intensity and onset but can influence the perceived duration if subtherapeutic concentrations are achieved. - The interplay of these pharmacokinetic parameters ultimately determines the drug's therapeutic window and frequency of dosing. *Clearance* - **Clearance** is the rate at which the active drug is removed from the body, primarily by the kidneys and liver. - A higher clearance generally leads to a shorter elimination half-life and a **shorter duration of action**, as the drug is removed more quickly from the systemic circulation. *Rate of elimination* - The **rate of elimination** directly dictates how quickly the concentration of a drug in the body decreases over time. - A faster elimination rate (shorter half-life) means the drug's effects will wear off sooner, resulting in a **shorter duration of action**. - This is quantified by the elimination rate constant (Kel) and half-life (t½). *Bioavailability* - **Bioavailability** refers to the fraction of an administered dose of unchanged drug that reaches the systemic circulation. - While bioavailability primarily affects the **peak concentration (Cmax)** and **intensity** of drug effect, it can indirectly influence duration. - If bioavailability is very low, therapeutic concentrations may not be sustained long enough, effectively shortening the **clinically relevant duration of action**. - However, two drugs with identical elimination rates but different bioavailabilities will have the same elimination half-life and similar duration at therapeutic doses.

Question 1

What is the most appropriate initial management for paralysis resulting from organophosphorus poisoning?

Accepted Answer

Supportive care, including respiratory support

Answer

Atropine to counteract muscarinic symptoms

Answer

Oximes to reactivate acetylcholinesterase

Answer

No specific antidote

Question 2

Which of the following glands is NOT typically involved in Multiple Endocrine Neoplasia type II A (MEN II A)?

Accepted Answer

Pituitary gland

Answer

Thyroid gland

Answer

Parathyroid gland

Answer

Adrenal gland

Question 3

Which of the following statements is false regarding hereditary spherocytosis?

Accepted Answer

Decreased MCHC

Answer

Defect in ankyrin

Answer

Reticulocytosis

Answer

Normal to increased MCV

Question 4

Intracorpuscular hemolytic anemia is seen in ?

Accepted Answer

Thalassemia

Answer

Infection

Answer

Thrombotic thrombocytopenic purpura (TTP)

Answer

Autoimmune hemolytic anemia

Question 5

Muscarinic cholinergic receptors are seen at all sites, except?

Accepted Answer

Neuromuscular junction

Answer

Stomach

Answer

CNS

Answer

Glands

Question 6

Which urinary bladder spasmolytic has local anesthetic properties?

Accepted Answer

Oxybutynin

Answer

Tamsulosin

Answer

Terazosin

Answer

Yohimbine

Question 7

Which of the following is classified as an antispasmodic agent?

Accepted Answer

Dicyclomine

Answer

Physostigmine

Answer

Tropicamide

Answer

None of the options

Question 8

Besides its properties of decreasing intraocular pressure, timolol is preferred in the treatment of glaucoma because it

Accepted Answer

Produces no miosis

Answer

Is a selective beta-adrenoceptor blocker

Answer

Increases outflow of aqueous humor

Answer

Possesses membrane stabilizing activity

Question 9

Which of the following is not a recognized use of alpha-2-agonists?

Accepted Answer

Benign Hyperplasia of prostate

Answer

Glaucoma

Answer

Hypertension

Answer

Sedation

Question 10

Which of the following factors influences the duration of action of a drug?

Accepted Answer

All of the options

Answer

Bioavailability

Answer

Clearance

Answer

Rate of elimination

NEET-PG 2013

Internal Medicine

Pathology

Pharmacology