Anatomy
1 questionsAnencephaly occurs due to the inability of the neural tube to close at which week of intrauterine life?
FMGE 2024 - Anatomy FMGE Practice Questions and MCQs
Question 91: Anencephaly occurs due to the inability of the neural tube to close at which week of intrauterine life?
- A. 2nd week
- B. 3rd week
- C. 4th week (Correct Answer)
- D. 5th week
Explanation: ***4th week***- The development of the **neural tube** occurs during the 4th week of intrauterine life, with the **anterior neuropore** normally closing around day 25 after conception. - Failure of this anterior closure, specifically at the cranial end during the 4th week, results in the severe congenital anomaly known as **anencephaly** [1].*3rd week*- The 3rd week is when **neurulation** (the folding of the neural plate) is initiated and the neural groove is formed, not when the final critical closure occurs.- The developing embryo is undergoing **gastrulation** during the 3rd week (formation of the three germ layers), preceding the completion of neural tube closure.*5th week*- By the 5th week, the neural tube is typically completely closed, and the process of **primary brain vesiculation** (forebrain, midbrain, hindbrain) is actively underway.- A closure defect leading to anencephaly would have necessarily occurred earlier, during the 4th week.*2nd week*- The 2nd week of development is characterized by the formation of the **bilaminar germ disc** (epiblast and hypoblast) and implantation.- **neurulation** (the process that forms the neural tube) does not begin until the start of the 3rd week, making the 2nd week too early for this specific closure defect.
Biochemistry
1 questionsWhich type of ion channel is affected by mutations in the CFTR gene?
FMGE 2024 - Biochemistry FMGE Practice Questions and MCQs
Question 91: Which type of ion channel is affected by mutations in the CFTR gene?
- A. Calcium
- B. Chloride (Correct Answer)
- C. Potassium
- D. Sodium
Explanation: ***Chloride***- The **CFTR** (Cystic Fibrosis Transmembrane Conductance Regulator) gene encodes an **ATP-gated chloride channel** that controls the movement of chloride ions across epithelial cell membranes.- Mutations in the CFTR gene cause defective chloride secretion and increased sodium and water reabsorption, leading to the dehydrated, thick mucus characteristic of **Cystic Fibrosis (CF)**.*Sodium*- While the lack of functional CFTR leads to excessive **sodium reabsorption** via the epithelial sodium channel (ENaC) in airways, CFTR itself is a chloride channel, not a sodium channel.- ENaC hyperactivity is a *secondary* effect resulting from the failure of CFTR to inhibit ENaC activity appropriately.*Potassium*- The primary role of the CFTR protein is not the regulation of potassium ions; potassium channels are distinct proteins involved in maintaining resting membrane potential and cell volume.- CFTR activity and the resultant disease phenotype are directly linked to chloride imbalance, not potassium transport defects.*Calcium*- CFTR does not function as a calcium channel; calcium channels are separate entities crucial for many cellular processes, including neurotransmitter release and muscle contraction.- Although intracellular calcium levels can sometimes modulate CFTR activity through signaling pathways, the channel protein itself transports chloride.
Internal Medicine
1 questionsWhich HLA is associated with Reiter syndrome?
FMGE 2024 - Internal Medicine FMGE Practice Questions and MCQs
Question 91: Which HLA is associated with Reiter syndrome?
- A. HLA-DQ8
- B. HLA-DR3
- C. HLA-DR4
- D. HLA-B27 (Correct Answer)
Explanation: ***HLA-B27*** - **HLA-B27** is the major histocompatibility complex (MHC) class I allele strongly associated with **Reiter syndrome** (now termed **Reactive Arthritis**) a component of the **seronegative spondyloarthropathies** [1]. - Approximately 60-80% of patients with Reactive Arthritis who present with the classic triad (urethritis, conjunctivitis, arthritis) are positive for **HLA-B27** [1]. *HLA-DR3* - **HLA-DR3** is primarily associated with several autoimmune disorders, including **Celiac Disease**, **Graves' Disease**, and **Systemic Lupus Erythematosus** (SLE). - It is an MHC class II allele, distinguishing it from the MHC class I linkage observed in Reactive Arthritis. *HLA-DQ8* - **HLA-DQ8** (often with HLA-DQ2) is a key genetic risk factor for **Celiac Disease**, playing a role in presenting gliadin peptides to T cells. - This allele is also associated with **Type 1 Diabetes Mellitus** but lacks a significant established association with the pathogenesis of the spondyloarthropathies. *HLA-DR4* - **HLA-DR4** carries the strongest genetic risk for **Rheumatoid Arthritis** (RA), particularly in individuals prone to developing severe, erosive disease. - While associated with generalized autoimmunity, **HLA-DR4** is not the primary marker for the seronegative spondyloarthropathies like Reactive Arthritis [2].
Ophthalmology
1 questionsConjunctival xerosis is caused by which vitamin deficiency?
FMGE 2024 - Ophthalmology FMGE Practice Questions and MCQs
Question 91: Conjunctival xerosis is caused by which vitamin deficiency?
- A. Vitamin K
- B. Vitamin C
- C. Vitamin D
- D. Vitamin A (Correct Answer)
Explanation: ***Vitamin A***- Vitamin A is crucial for the maintenance and differentiation of **epithelial cells**, including those of the conjunctiva.- Deficiency leads to **xerophthalmia**, starting with **night blindness** and progressing to **conjunctival xerosis** (dryness) and eventual **keratomalacia**.*Vitamin K*- Vitamin K is essential for the hepatic synthesis of **clotting factors** (II, VII, IX, X).- Deficiency results in a **coagulopathy** characterized by **excessive bleeding** and prolonged prothrombin time (PT).*Vitamin C*- Vitamin C (*ascorbic acid*) is vital for the hydroxylation of **proline and lysine** during **collagen synthesis**.- Deficiency causes **Scurvy**, symptomatically involving **fragile capillaries**, **gingival swelling and bleeding**, and impaired wound healing.*Vitamin D*- Vitamin D's primary role is regulating **calcium and phosphate metabolism** to maintain bone health.- Deficiency leads to **Rickets** in children and **Osteomalacia** in adults, primarily affecting the skeletal system.
Pediatrics
1 questionsA child with diarrhea was eager to drink, and the skin pinch went back slowly. Which of the following categories is the child classified into as per IMNCI?
FMGE 2024 - Pediatrics FMGE Practice Questions and MCQs
Question 91: A child with diarrhea was eager to drink, and the skin pinch went back slowly. Which of the following categories is the child classified into as per IMNCI?
- A. Green
- B. None
- C. Pink
- D. Yellow (Correct Answer)
Explanation: ***Yellow***- This classification applies when the child shows two or more signs of **'Some Dehydration'** according to IMNCI guidelines, which include **eagerly drinking/thirst** and the **skin pinch going back slowly** (less than 2 seconds but noticeably delayed).- The management for the Yellow category involves treating dehydration using **Oral Rehydration Salts (ORS)** (Plan B).*Pink*- The **Pink (Severe Dehydration) category** requires at least two signs such as **lethargy/unconsciousness**, inability to drink/drinking poorly, or the **skin pinch going back very slowly** (≥ 2 seconds).- The child is **eager to drink**, which rules out the severe dehydration sign of being **unable to drink** or **drinking poorly**.*Green*- The **Green (No Dehydration) category** is applied when the child does not exhibit sufficient signs to classify them into the 'Some' or 'Severe' dehydration categories.- Since the child demonstrates two definite signs of dehydration (**thirst** and **slow skin pinch**), the 'No Dehydration' classification is incorrect.*None*- IMNCI provides specific and comprehensive categories (**Green, Yellow, Pink**) for classifying dehydration status based on clinical signs.- The combination of **eager drinking** and **slow skin pinch** definitively places the child in the **Yellow (Some Dehydration)** category.
Pharmacology
3 questionsA patient was given an antipsychotic drug, haloperidol, and the patient developed acute dystonia. Which is the next best step?
A group of people are travelling to the mountains, and a girl starts complaining of mountain sickness. What is the drug of choice?
Which of the following is an atypical antipsychotic with the least metabolic side effects?
FMGE 2024 - Pharmacology FMGE Practice Questions and MCQs
Question 91: A patient was given an antipsychotic drug, haloperidol, and the patient developed acute dystonia. Which is the next best step?
- A. Give Fluphenazine
- B. Give Benztropine (Correct Answer)
- C. Increase dose of haloperidol
- D. Change to clozapine
Explanation: ***Give Benztropine***- **Acute dystonia** is a severe extrapyramidal symptom (EPS) requiring rapid intervention, often treated intramuscularly or intravenously.- **Benztropine** (an anticholinergic agent) is the drug of choice for the immediate management of acute dystonia, working to restore the balance between dopamine and acetylcholine.*Change to clozapine*- While **clozapine** has a significantly lower risk of causing acute dystonia, it is not the initial treatment for an acute episode due to its slow titration requirements and side-effect profile.- Switching to clozapine is a long-term strategy for patients intolerant to other antipsychotics, not an acute rescue medication.*Give Fluphenazine*- **Fluphenazine** is a high-potency first-generation antipsychotic, similar to haloperidol, which also carries a high risk of EPS.- Administering another high-potency antipsychotic would perpetuate the excessive **dopaminergic blockade** responsible for the acute dystonia.*Increase dose of haloperidol*- **Acute dystonia** is a direct dose-related side effect of D2 receptor blockade by haloperidol in the nigrostriatal pathway.- Increasing the dose of **haloperidol** would worsen the underlying neurochemical imbalance, thereby intensifying the dystonic symptoms.
Question 92: A group of people are travelling to the mountains, and a girl starts complaining of mountain sickness. What is the drug of choice?
- A. Thiazide
- B. Acetazolamide (Correct Answer)
- C. Promethazine
- D. Dimenhydrinate
Explanation: ***Acetazolamide*** - This drug is the agent of choice for prophylaxis and treatment of **Acute Mountain Sickness (AMS)** due to its ability to accelerate **acclimatization**. - It functions as a **carbonic anhydrase inhibitor**, inducing a mild metabolic acidosis that stimulates the respiratory center, thereby increasing ventilation and improving blood oxygen saturation. *Promethazine* - This is an **antihistamine** (H1 blocker) often used for its potent **antiemetic** (nausea) and sedative effects. - While it may relieve nausea symptoms associated with AMS, it does not address the underlying physiological disturbances or enhance **acclimatization**. *Dimenhydrinate* - This medication is also an **antihistamine** typically employed to treat and prevent **motion sickness** and vertigo. - It lacks the crucial physiological mechanism (carbonic anhydrase inhibition) required to improve breathing efficiency and accelerate the body's response to **hypoxia**. *Thiazide* - This category of drugs, such as hydrochlorothiazide, are **diuretics** primarily used for hypertension and edema. - They do not possess the necessary respiratory stimulation properties of **Acetazolamide** and are therefore ineffective in treating or preventing mountain sickness.
Question 93: Which of the following is an atypical antipsychotic with the least metabolic side effects?
- A. Risperidone
- B. Ziprasidone (Correct Answer)
- C. Haloperidol
- D. Quetiapine
Explanation: ***Ziprasidone*** - Among the atypical (second-generation) antipsychotics, **Ziprasidone** has the lowest risk regarding adverse **metabolic side effects**, including **weight gain**, dyslipidemia, and insulin resistance. - Due to its minimal impact on metabolic parameters, it is a preferred choice for patients with pre-existing **cardiovascular risk factors** or obesity. *Haloperidol* - Haloperidol is a **first-generation (typical)** antipsychotic, which primarily risks **extrapyramidal symptoms (EPS)** and elevated prolactin, rather than being an atypical agent. - While its metabolic risk is generally lower than high-risk atypicals (e.g., Olanzapine), it is not the correct classification for answering a question focusing on *atypical* drugs. *Risperidone* - Risperidone is an atypical antipsychotic but carries a **moderate to high risk** of causing significant **weight gain** and **hyperprolactinemia**. - Its metabolic profile is considerably worse than that of Ziprasidone or Aripiprazole. *Quetiapine* - Quetiapine carries a substantial risk profile regarding metabolic adverse effects, specifically high rates of **sedation** and clinically significant **weight gain**. - It is frequently linked to the development of **dyslipidemia** and **Type 2 diabetes mellitus**.
Physiology
1 questionsWhich of the following oxygen-sensitive channels is present in peripheral chemoreceptors?
FMGE 2024 - Physiology FMGE Practice Questions and MCQs
Question 91: Which of the following oxygen-sensitive channels is present in peripheral chemoreceptors?
- A. Ca++
- B. Na+
- C. K+ (Correct Answer)
- D. Cl-
Explanation: ***K+***- **Oxygen-sensitive K+ channels**, specifically members of the **TASK-like potassium channels** family, are central to the response of **glomus cells** in the carotid body to **hypoxia**.- When oxygen levels fall, these channels are **inhibited**, reducing K+ efflux and causing the cell membrane to **depolarize**, initiating the signaling cascade.*Na+*- While **voltage-gated Na+ channels** are essential for action potential generation in the afferent nerve, they are not the primary channels that directly sense changes in **pO2** within the glomus cells.- The initial depolarizing signal stems from the inhibition of K+ channels, not the activation or inhibition of Na+ channels.*Ca++*- **Voltage-gated Ca++ channels** open in response to the **depolarization** caused by K+ channel inhibition upon hypoxia.- The resulting **calcium influx** is mandatory for the final step: triggering the release of **neurotransmitters** (e.g., dopamine, ATP) that signal the brainstem.*Cl-*- **Cl- channels** (Chloride channels) are present in glomus cells and help regulate cell volume and membrane potential, but they do not function as the mechanism's primary oxygen sensor.- The entire chemosensing process is primarily governed by the modulation of **cation** movement (K+ efflux and subsequent Ca++ influx) rather than chloride flux.
Radiology
1 questionsWhich among the following is the least radiosensitive cell?
FMGE 2024 - Radiology FMGE Practice Questions and MCQs
Question 91: Which among the following is the least radiosensitive cell?
- A. Lymphocytes
- B. Neutrophils
- C. Monocytes
- D. Platelets (Correct Answer)
Explanation: ***Platelets*** - Platelets are **anuclear cell fragments** derived from megakaryocytes, lacking a nucleus and DNA, which makes them highly resistant to the direct cytotoxic effects of radiation. - They are one of the **least radiosensitive** circulating components; platelet counts typically require very high radiation doses to fall significantly. *Monocytes* - Monocytes are generally considered **moderately radiosensitive**, more susceptible to radiation-induced death than mature neutrophils or platelets. - They exhibit susceptibility to **interphase death** upon irradiation, although less sensitive than lymphocytes. *Lymphocytes* - Lymphocytes are the **most radiosensitive** mature circulating blood cells, undergoing rapid apoptosis (programmed cell death) even at low radiation doses (sub-2 Gy). - Their high sensitivity relates to their dependence on DNA integrity for survival and their prompt initiation of the **apoptotic pathway** following damage. *Neutrophils* - Mature neutrophils are considered relatively radiosensitive, but significantly **less sensitive than lymphocytes** and moderately less sensitive than monocytes. - Their numbers drop less rapidly than lymphocytes primarily because of a large pre-formed **reserve pool** in the bone marrow, providing temporary protection.