Progressive distal-to-proximal motor recovery following nerve regeneration is most characteristic of which type of nerve injury?
Which of the following complications is commonly associated with mitral valve prolapse?
Which type of fatty acids should be included in the diet to manage chyluria?
Renal vein thrombosis is associated with all of the following conditions except:
Which of the following is NOT typically seen in 3rd nerve palsy?
What is the most likely diagnosis for a young patient presenting with iritis and joint pain?
Among the following, most reliable test for screening of diabetes mellitus?
HIV post exposure prophylaxis should be started within?
What is the most common cause of ophthalmoplegia in adults?
A 45-year-old patient presents with progressive dyspnea, orthopnea, and bilateral pedal edema. On examination, there is elevated JVP, S3 gallop, and hepatomegaly. What is the most likely underlying pathophysiology?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 21: Progressive distal-to-proximal motor recovery following nerve regeneration is most characteristic of which type of nerve injury?
- A. Axonotmesis (Correct Answer)
- B. Neurotmesis
- C. Neuropraxia
- D. Nerve injury
Explanation: ***Axonotmesis*** - Involves damage to the **axon** and myelin sheath, while the surrounding **epineurium** remains intact. - This preservation of the connective tissue allows for guided **regeneration** of axons from distal to proximal, leading to a good prognosis for recovery [1]. *Neurotmesis* - Refers to the **complete transection** of the nerve, including the axon, myelin, and all connective tissue sheaths. - Recovery is often **incomplete** or requires surgical repair, as significant misdirection of regenerating axons is common. *Neuropraxia* - Characterized by a **temporary block** in nerve conduction, typically due to **demyelination**, with the axon remaining intact. - Recovery is usually **rapid** and complete, occurring within days to weeks, as no axonal regeneration is needed. *Nerve injury* - This is a **general term** that encompasses all types of nerve damage, from mild to severe. - It does not specify a particular mechanism or pattern of recovery, making it less precise than the more specific classifications.
Question 22: Which of the following complications is commonly associated with mitral valve prolapse?
- A. Ventricular arrhythmia
- B. Stroke
- C. Infective endocarditis (Correct Answer)
- D. Mitral stenosis
Explanation: Mitral valve prolapse (MVP) involves myxomatous degeneration of the mitral valve leaflets, which can create a rough surface predisposing to bacterial adhesion and subsequent infective endocarditis [1]. While the overall risk is low, patients with MVP and accompanying mitral regurgitation or thickened leaflets are at higher risk [1]. Patients with valvular heart disease are generally susceptible to bacterial endocarditis, often associated with procedures or dental hygiene [2]. Stroke - Although MVP can sometimes be associated with embolic events (e.g., from thrombi forming on the prolapsing valve), stroke is not considered a commonly associated complication. - The risk of stroke is generally higher in MVP patients with concomitant atrial fibrillation or other cardiovascular risk factors. Mitral stenosis - Mitral valve prolapse is characterized by the displacement of mitral valve leaflets into the left atrium during systole, which can lead to mitral regurgitation [3], not stenosis. - Mitral stenosis involves narrowing of the mitral valve orifice, usually due to rheumatic fever, which is a different pathophysiology [4]. Ventricular arrhythmia - While palpitations (often benign supraventricular ectopy) are common in MVP, clinically significant ventricular arrhythmias are less common. - Severe ventricular arrhythmias are more typically seen with significant underlying myocardial disease or severe mitral regurgitation causing left ventricular dysfunction.
Question 23: Which type of fatty acids should be included in the diet to manage chyluria?
- A. Short-chain fatty acids
- B. Medium-chain fatty acids (Correct Answer)
- C. Long-chain fatty acids
- D. Omega-3 fatty acids
Explanation: ***Medium-chain fatty acids*** - **Medium-chain fatty acids (MCFAs)** are absorbed directly into the **portal circulation** without being re-esterified to triglycerides or incorporated into chylomicrons [1]. This helps bypass the compromised lymphatic system. - In **chyluria**, the lymphatic system's integrity is disrupted, leading to leakage of **chyle** (lymphatic fluid rich in chylomicrons) into the urinary tract. MCFAs provide a source of fat that does not rely on the lymphatic pathway for transport [1]. *Short-chain fatty acids* - **Short-chain fatty acids (SCFAs)** are primarily produced by bacterial fermentation in the colon and are absorbed directly into the portal circulation. - While they do not rely on the lymphatic system, their dietary contribution as a significant energy source is limited, and they are not the primary fat source for patients with chyluria. *Long-chain fatty acids* - **Long-chain fatty acids (LCFAs)** are absorbed with the help of bile salts, re-esterified into triglycerides, and packaged into **chylomicrons** within the intestinal cells [2]. - These chylomicrons then enter the **lymphatic system** and eventually the bloodstream, which is precisely the pathway that is compromised in chyluria, making them unsuitable [2]. *Omega-3 fatty acids* - **Omega-3 fatty acids** are a type of **long-chain polyunsaturated fatty acid** that also follow the chylomicron-lymphatic pathway for absorption [3]. - While beneficial for other health aspects, they are not suitable for managing chyluria due to their reliance on the **lymphatic system** for transport, which is dysfunctional in this condition.
Question 24: Renal vein thrombosis is associated with all of the following conditions except:
- A. Nephrotic syndrome
- B. Dehydration
- C. Sickle cell anemia
- D. Trauma (Correct Answer)
Explanation: **Trauma** - While trauma to the abdomen can cause **renal injury** and other vascular issues, isolated **renal vein thrombosis** is not a common direct association or complication [1]. - Renal vein thrombosis typically results from conditions that lead to a **hypercoagulable state** or local vascular stasis. *Sickle cell anemia* - Individuals with **sickle cell anemia** are prone to **vaso-occlusive crises** from sickled red blood cells obstructing blood flow [2]. - This can lead to **renal medullary ischemia** and infarction, making them highly susceptible to **renal vein thrombosis**. *Nephrotic syndrome* - **Nephrotic syndrome** is a significant risk factor for **renal vein thrombosis** due to the urinary loss of **antithrombin III**, a natural anticoagulant. - This loss creates a **hypercoagulable state**, increasing the likelihood of thrombus formation in renal veins. *Dehydration* - Severe **dehydration** leads to **hemoconcentration** (increased blood viscosity) and reduced blood flow. - These factors promote a **hypercoagulable state**, increasing the risk of thrombotic events, including **renal vein thrombosis**, especially in vulnerable populations like infants or the elderly.
Question 25: Which of the following is NOT typically seen in 3rd nerve palsy?
- A. Mydriasis
- B. Ptosis
- C. Loss of abduction (Correct Answer)
- D. Loss of light reflex
Explanation: ***Loss of abduction*** - The **oculomotor nerve (CN III)** controls adduction, elevation, and depression of the eye, but **not abduction**. [2] - **Abduction** is primarily controlled by the **abducens nerve (CN VI)**, so its loss would indicate a CN VI palsy. *Mydriasis* - The **oculomotor nerve (CN III)** innervates the **parasympathetic fibers** to the pupillary constrictor muscles. [3] - Palsy of these fibers leads to unopposed action of the sympathetic dilator muscles, causing **mydriasis (pupil dilation)**. [4] *Ptosis* - The **oculomotor nerve (CN III)** innervates the **levator palpebrae superioris muscle**, which lifts the eyelid. - Dysfunction of this nerve leads to **ptosis (drooping of the eyelid)**. [1] *Loss of light reflex* - The **efferent pathway** for the **pupillary light reflex** travels via the **oculomotor nerve (CN III)** to constrict the pupil. [3] - A 3rd nerve palsy, particularly affecting the parasympathetic fibers, **impairs pupillary constriction**, resulting in a loss of the direct and consensual light reflex in the affected eye. [4]
Question 26: What is the most likely diagnosis for a young patient presenting with iritis and joint pain?
- A. Gout
- B. RA
- C. AS (Correct Answer)
- D. Toxoplasma
Explanation: ***AS (Ankylosing Spondylitis)*** - **Iritis** (anterior uveitis) is a common extra-articular manifestation of **ankylosing spondylitis**, affecting up to 40% of patients [1]. - **Joint pain**, particularly in the axial skeleton (spine and sacroiliac joints), is a hallmark feature in young patients with AS [1]. *Gout* - Characterized by **recurrent attacks of acute inflammatory arthritis** due to **monosodium urate crystal deposition**. - While it causes severe joint pain, **iritis is not a typical manifestation** of gout. *RA (Rheumatoid Arthritis)* - RA is a **chronic autoimmune inflammatory disease** primarily affecting the **synovial joints** symmetrically, mostly in older adults. - While ocular manifestations like **scleritis** or **episcleritis** can occur, **iritis is less common** compared to AS. *Toxoplasma* - **Toxoplasmosis** primarily causes **chorioretinitis** (inflammation of the choroid and retina), not typically isolated iritis. - Although it can cause **arthralgia** (joint pain), it does not cause inflammatory arthritis like the spondyloarthropathies.
Question 27: Among the following, most reliable test for screening of diabetes mellitus?
- A. Urine sugar
- B. Random sugar
- C. Fasting sugar (Correct Answer)
- D. Glucose tolerance test
Explanation: ***Fasting sugar*** - A **fasting plasma glucose** (FPG) test is the most common and reliable initial test for screening for **diabetes mellitus** because it measures blood glucose after an overnight fast (typically 8-12 hours), providing a baseline level unaffected by recent food intake [1]. - A fasting glucose level of **≥ 126 mg/dL** (7.0 mmol/L) on two separate occasions is diagnostic of diabetes, making it an excellent screening tool for identifying individuals with impaired glucose metabolism [1]. *Random sugar* - A random plasma glucose test can be used to diagnose diabetes if the level is **≥ 200 mg/dL** (11.1 mmol/L) in a symptomatic individual, but it is less reliable for screening asymptomatic individuals due to its variability depending on recent food intake [1]. - Because it can be measured at any time of day without regard to the last meal, it has a **lower sensitivity** for detecting early stages of diabetes compared to fasting glucose. *Glucose tolerance test* - An **oral glucose tolerance test** (OGTT) is highly sensitive and specific for diagnosing diabetes and impaired glucose tolerance, but it is more cumbersome and time-consuming, involving multiple blood draws over two hours after consuming a sugary drink. - While it is a definitive diagnostic test, its complexity makes it **less practical for routine screening** in large populations compared to simpler tests like fasting plasma glucose. *Urine sugar* - The presence of glucose in urine (glycosuria) indicates that blood glucose levels have exceeded the **renal threshold** (typically around 180 mg/dL), meaning the kidneys are unable to reabsorb all the glucose. - This is a **less sensitive and specific** method for screening, as it only becomes positive once blood glucose is significantly elevated, and it does not detect milder forms of impaired glucose metabolism or early diabetes.
Question 28: HIV post exposure prophylaxis should be started within?
- A. 1-2 hrs
- B. 14 hrs
- C. 18 hrs
- D. 72 hrs (Correct Answer)
Explanation: ***72 hrs*** - **Post-exposure prophylaxis (PEP)** aims to prevent HIV infection after potential exposure and should ideally be initiated as soon as possible, but no later than **72 hours** after exposure [1]. - Starting PEP within this window significantly increases its effectiveness in preventing HIV seroconversion. *1-2 hrs* - While initiating PEP as soon as possible is crucial, stating it must be within **1-2 hours** can be misleading as the window of effectiveness extends beyond this. - This timeframe might be an ideal, but not the absolute crucial limit for efficacy. *14 hrs* - This timeframe is **too restrictive** for the recommended window for PEP initiation. - Missing the opportunity within **14 hours** does not negate the effectiveness of PEP if started within the broader 72-hour window. *18 hrs* - Similar to **14 hours**, **18 hours** is an unnecessarily strict limit for PEP initiation. - Guidelines universally support starting PEP up to **72 hours** post-exposure for optimal benefit [1].
Question 29: What is the most common cause of ophthalmoplegia in adults?
- A. Cranial nerve palsy (Correct Answer)
- B. Myasthenia gravis
- C. Diabetes mellitus
- D. Trauma
Explanation: ***Cranial nerve palsy*** - **Cranial nerve palsies**, particularly those affecting cranial nerves III, IV, or VI, are the most frequent causes of isolated ophthalmoplegia in adults [1]. - They can result from various etiologies like **ischemia**, **compression**, or **inflammation**, directly impairing the nerves responsible for eye movement [1]. *Myasthenia gravis* - While it frequently causes **ocular symptoms** (ptosis and diplopia), it typically presents with **fluctuating weakness** that worsens with sustained effort [1]. - It's a neuromuscular junction disorder, not a primary cranial nerve issue, and often affects other muscle groups beyond the eyes. *Diabetes mellitus* - **Diabetic ophthalmoplegia** is a specific type of cranial nerve palsy (often CN III or VI) caused by microvascular ischemia. - While common in diabetics, it is a *cause* of cranial nerve palsy, not the overarching most common cause of ophthalmoplegia itself. *Trauma* - **Trauma** can certainly cause ophthalmoplegia, often due to direct damage to **extraocular muscles**, **orbital fractures**, or **cranial nerve injury**. - However, in the general adult population, non-traumatic cranial nerve palsies are more frequently encountered as the cause of ophthalmoplegia.
Question 30: A 45-year-old patient presents with progressive dyspnea, orthopnea, and bilateral pedal edema. On examination, there is elevated JVP, S3 gallop, and hepatomegaly. What is the most likely underlying pathophysiology?
- A. DALEY
- B. HALE (Correct Answer)
- C. OALY
- D. None of the options
Explanation: ***HALE*** - This acronym stands for **Heart-failure Associated Lung Edema**. The symptoms of **progressive dyspnea**, **orthopnea**, **bilateral pedal edema**, **elevated JVP**, **S3 gallop**, and **hepatomegaly** are classic signs of **congestive heart failure** leading to fluid overload and pulmonary congestion [1]. - The pathophysiology involves the heart's inability to pump blood effectively, causing a buildup of pressure in the pulmonary and systemic circulations, leading to the observed symptoms [1]. *DALEY* - This is not a recognized acronym in medical pathophysiology. The symptoms presented are strongly indicative of a specific cardiovascular condition. - There is no clinical scenario where "DALEY" would accurately describe the underlying pathophysiology of dyspnea, edema, and heart failure signs. *OALY* - This is not a recognized acronym in medical pathophysiology. The presented clinical picture requires a well-established and specific pathophysiological explanation. - Using an unrecognized term would not provide an accurate or helpful description of the patient's condition. *None of the options* - The acronym HALE (Heart-failure Associated Lung Edema) accurately captures the core pathophysiology evident from the patient's symptoms and signs. - Given the strong clinical presentation of congestive heart failure with pulmonary and systemic congestion, one of the provided options *does* accurately describe the situation.