NEET-PG 2025 - Internal Medicine Practice Questions

Q: Patient came with severe headache and seizures. Sodium on admission was 98 meq/L. We have started correction with 3 % saline and now after 24 hours of infusion sodium is 110 meq/L. Patient develops mutism and altered sensorium. Which investigation will you perform now?

MRI Head. ***MRI Head*** - A rapid correction of **severe chronic hyponatremia** (from 98 to 110 mEq/L in 24 hours, exceeding the recommended limit of 8-10 mEq/L) puts the patient at very high risk for **Osmotic Demyelination Syndrome (ODS)** (previously Central Pontine Myelinolysis). [1] - The new onset of **mutism** and **altered sensorium** are classic, late symptoms of ODS, necessitating an **MRI head** to visualize characteristic **pontine** (and sometimes extrapontine) lesions. *LP for CSF biochemistry* - LP is primarily indicated for diagnosing infections or inflammatory conditions of the CNS, which is less likely given the clear history of electrolyte imbalance and complication following rapid correction. - While CSF analysis can reveal demyelination products, an **MRI** is the definitive, non-invasive imaging modality for diagnosing ODS. *Brainstem evoked potentials* - Brainstem auditory evoked potentials (BAEP) primarily assess the **integrity of the auditory pathways** through the brainstem. [2] - While ODS affects the brainstem, BAEP is not the standard or most sensitive first-line investigation for confirming demyelinating lesions in the pons. *EEG* - EEG measures the electrical activity of the cerebral cortex and is primarily useful for localizing seizure foci or assessing the severity of encephalopathy. [2] - The symptoms (mutism, altered sensorium) point strongly to a structural brainstem lesion (ODS), which is best confirmed by **MRI head**, not EEG.

Q: A 68-year-old male with a history of COPD presents to the emergency room with severe dyspnea and altered mental status. An arterial blood gas (ABG) is drawn with the following results: pH: 7.28 PaCO2: 60 mmHg HCO3-: 28 mEq/L Na+: 142 mEq/L Cl-: 100 mEq/L Based on these results, what is the calculated anion gap?

B. 14 mEq/L. ***14 mEq/L*** - The **anion gap (AG)** is calculated using the formula: $\text{AG} = [\text{Na}^+] - ([\text{Cl}^-] + [\text{HCO}_3^-])$. [1] - Plugging in the patient's values: $142 - (100 + 28) = 142 - 128 = **14 \text{ mEq/L}**$. *10 mEq/L* - This value is below the calculated 14 mEq/L and would be considered low if the normal range upper limit is 12, suggesting a calculation error. [1] - An anion gap of 10 mEq/L is typically a normal value, but it is not the mathematically correct result based on the patient's **serum electrolyte** values. *18 mEq/L* - Obtaining this value would imply that $[\text{Cl}^-] + [\text{HCO}_3^-]$ equaled 124 mEq/L ($142 - 18$), which is incorrect as the sum is **128 mEq/L**. - An anion gap of 18 mEq/L indicates a **High Anion Gap Metabolic Acidosis (HAGMA)**, which is metabolically possible but mathematically inconsistent with the provided electrolyte numbers. [1] *24 mEq/L* - This value is significantly higher than 14 mEq/L and would suggest a severe uncompensated **HAGMA** (e.g., severe ketoacidosis or lactic acidosis). [1] - The calculation based on the given **plasma concentrations** of sodium, chloride, and bicarbonate simply does not support this result.

Q: Based on the image provided, what is the most appropriate confirmatory investigation?

Manometry. ***Manometry*** - Esophageal manometry is the **gold standard** (confirmatory test) for achalasia, as it directly evaluates the motility and pressure patterns of the esophagus. - It definitively demonstrates the two key pathognomonic findings: **absent esophageal peristalsis** and **incomplete relaxation of the lower esophageal sphincter (LES)**. *pH monitoring* - This test is used primarily to diagnose **Gastroesophageal Reflux Disease (GERD)** by quantifying abnormal acid exposure in the distal esophagus. - It is not relevant for confirming achalasia, which is a **motor disorder** causing functional obstruction, not acid reflux. *Upper GI Endoscopy* - Endoscopy is crucial for **ruling out secondary achalasia** (pseudoachalasia), caused by underlying conditions like malignancy, which can structurally mimic the radiologic findings. - Although mandatory in evaluation, it does not confirm the **functional motor deficit** (aperistalsis and failed relaxation) required for definitive diagnosis of primary achalasia. *Barium swallow study* - The image provided is a Barium swallow study, which serves as the **initial screening tool** for achalasia by showing the classic **"bird-beak" appearance** of the distal esophagus. - While suggestive, this radiological study reports morphology and transit, but **manometry** is required to confirm the associated physiological defect (abnormal pressures and motility).

Q: A patient presents with palpitations and an irregularly irregular pulse. He presents within 2 hours of symptom onset, and has no history of diabetes or other comorbidities. What is the most appropriate initial management?

Cardioversion. ***Cardioversion*** - Since the patient presented within **<12 hours** of symptom onset (paroxysmal AF) and is hemodynamically stable, particularly without comorbidities, urgent rhythm control via **cardioversion (electrical or pharmacological)** is the optimal management to restore sinus rhythm [1]. - The very early presentation (within 2 hours) and the absence of significant comorbidities suggest a good chance for maintenance of sinus rhythm without immediate concern for complex thrombus formation. *TEE for starting anticoagulation* - **Transesophageal echocardiography (TEE)** is performed to rule out left atrial appendage thrombus before cardioversion if the duration of AF is **unknown or >48 hours**, or if anticoagulation has been inadequate (less than 3 weeks). - In this case, since the onset is clearly 48 hours** ago. - For new-onset AF with a short duration, **rhythm control** (cardioversion) is preferred [1]. *Wait and watch* - **Wait and watch** is inappropriate as **atrial fibrillation (AF)** is associated with a high risk of systemic embolization and stroke, necessitating prompt management (either rhythm or rate control). - Immediate intervention is required to prevent complications and potentially restore sinus rhythm, especially given the very early presentation.

Q: A patient presents with sudden onset aphasia and right sided arm weakness for past 4 hours. Which of the following investigations will be done to determine etiology of this case presentation?

Transesophageal echocardiography. ***Transesophageal echocardiography*** - The patient presents with **sudden onset focal neurological deficits** (aphasia and hemiparesis), highly suggestive of an acute stroke, likely ischemic [2]. - TEE is superior to TTE for visualizing potential **cardiac sources of embolism**, such as intracardiac thrombi (especially in the left atrial appendage), patent foramen ovale (PFO), or aortic arch plaques, which are common etiologies in cryptogenic stroke [1], [4]. *Transthoracic echocardiography* - TTE is the initial, non-invasive cardiac evaluation but may miss smaller defects or clots, particularly in the **left atrial appendage** or smaller PFOs, due to poor resolution. - While useful for overall cardiac function, it has **lower sensitivity** than TEE for detecting specific high-risk embolic sources. *Carotid doppler* - This test assesses **carotid artery stenosis**, which is a common cause of ipsilateral stroke [1]. - It primarily determines large vessel disease in the neck, but the clinical presentation (sudden onset) and age may also suggest a **cardioembolic source** warranting cardiac investigation. *MRI brain* - MRI brain is the standard imaging modality used to **confirm the stroke** (especially DWI in the acute stage) and localize the lesion [1], [3]. - However, it determines the **consequence of the stroke** (location and extent of damage) rather than the underlying **etiology** (the source of the embolus or infarct), which is the focus of this question [1], [4].

Q: A patient presents with salt wasting, craving, hyperkalemia, metabolic acidosis, and skin pigmentation. What is the most likely diagnosis?

Addison's disease. ***Addison's disease*** - The features (salt wasting, hyperkalemia, metabolic acidosis, and skin pigmentation) are hallmarks of **primary adrenal insufficiency** (Addison's disease) [1], [2]. - **Skin pigmentation** (due to increased ACTH/MSH) and **salt wasting** (due to cortisol and aldosterone deficiency) are key differentiating points [2]. *Cushing's syndrome* - This condition is caused by **excess glucocorticoids** and typically presents with central obesity, moon facies, hypertension, and hypokalemia [3]. - It is characterized by **fluid retention** and suppressed ACTH (in secondary/tertiary causes), entirely opposite to the salt wasting seen here [3]. *Conn's syndrome* - Conn's syndrome is **primary hyperaldosteronism**, leading to sodium retention, **hypertension**, **hypokalemia**, and metabolic alkalosis [1]. - The presentation includes **hypokalemia** and **alkalosis**, which directly contradict the hyperkalemia and acidosis noted in the patient. *Pheochromocytoma* - This is a catecholamine-secreting tumor leading to episodic or sustained **hypertension**, palpitations, headaches, and sweating. - It primarily affects the cardiovascular system and does not cause the **salt wasting** or **hyperkalemia** profile seen in this patient.

Q: A known type 1 diabetic presents with glucose 799 mg/dL, Na+ 128 mEq/L, Cl- 88 mEq/L, and signs of dehydration. Which of the following is NOT used in the initial management?

3 % Saline. Hypotonic conditions in Diabetic Ketoacidosis (DKA) are typically addressed with isotonic fluids. 3% saline is not used in initial management because it is reserved for severe cerebral edema or profound hypovolemia [3]. The immediate priority for fluid resuscitation in DKA is often 0.9% Normal Saline to correct volume depletion and hypotonicity [2], [4]. *0.9 % Normal saline* - This is essential for volume resuscitation to correct the severe dehydration (due to osmotic diuresis) and is the standard initial fluid administered in DKA [1], [2]. - It helps restore effective circulating volume and is initiated before insulin therapy to prevent vascular collapse [4]. *IV infusion insulin* - After initial fluid therapy is initiated, IV regular insulin infusion is crucial to transition the patient from a catabolic to an anabolic state, stopping ketone production and lowering blood glucose levels [2]. - Insulin therapy must be delayed until fluid resuscitation begins to prevent vascular collapse [4]. *Potassium monitoring* - Continuous and careful potassium monitoring is vital because acidosis and cellular shifts lead to rapid changes in serum potassium levels [2], [3]. - Potassium supplementation is often required if the serum potassium is < 5.5 mmol/L (or 5.2 mEq/L) to prevent life-threatening cardiac arrhythmias [2].

Q: A 55-year-old man presents with altered sensorium and deep labored breathing. ABG is given below. What is the most likely acid-base disorder? pH: 7.20 pCO₂: 31 mmHg HCO₃⁻:16 mEq/L Na⁺: 130 mEq/L Cl⁻: 84 mEq/L PaO₂: 80 mmHg

Metabolic acidosis. ***Metabolic acidosis*** - The **low pH (7.20)** indicates **acidosis** [2]. The primary cause is low **bicarbonate (HCO₃⁻ 16 mEq/L)**, defining it as metabolic acidosis [1]. - This patient presents with **Kussmaul breathing** (deep, labored breathing) as a respiratory attempt to compensate (blowing off CO₂) for the underlying metabolic acidosis, suggested by the low **pCO₂ (31 mmHg)** [1]. *Metabolic alkalosis* - This would be characterized by a **high pH (>7.45)** and a **high HCO₃⁻** level, which is the opposite of the current findings [3]. - Commonly caused by conditions like **vomiting** or excessive intake of **alkali** substances [3]. *Respiratory acidosis* - This requires a **high pCO₂ (>45 mmHg)**, which is the cause of acidemia, typically due to **hypoventilation** or respiratory failure [2]. - The current pCO₂ (31 mmHg) is low, indicating **hyperventilation** (compensation). *Respiratory alkalosis* - This would show a **high pH (>7.45)** caused by a **low pCO₂ (<35 mmHg)** due to **hyperventilation** (e.g., anxiety, high altitude) [2]. - While pCO₂ is low, the pH is acidic (7.20), not alkaline, ruling out primary respiratory alkalosis [2].

Q: Old man underwent joint replacement surgery 3 days ago. Today he develops SOB with chest pain. O/E : pulse 100/min, BP 100/70 mm Hg, RR28/min and sp02: 85% room air. D-dimer is elevated. Which is the next best test

CTPA. ***CTPA*** - This is the **gold standard** for diagnosing acute pulmonary embolism (PE) by visualizing the filling defects in the pulmonary arteries [2]. - Given the high clinical suspicion (post-operative status, classical symptoms, elevated D-dimer) and hemodynamic instability, rapid confirmation with **CTPA** is essential for determining the need for treatments like thrombolysis [2], [3]. *V/Q scan* - **V/Q scans** are generally reserved for patients where CTPA is contraindicated, such as in severe renal failure or certain allergies, and are typically not performed in unstable patients [2]. - It frequently yields an intermediate probability result, which is less conclusive than a CTPA, especially when a definitive, rapid diagnosis is needed due to **hemodynamic compromise**. *ECG* - **ECG** is a vital part of the initial assessment to rule out conditions like acute myocardial infarction and to check for signs of right heart strain common in massive PE (e.g., S1Q3T3 pattern) [1]. - Although crucial for risk stratification, it is only a **supportive test** and is not the definitive diagnostic tool for confirming the presence of PE. *CXR* - The **CXR** is primarily useful for excluding other pulmonary pathologies that mimic PE, such as pneumonia or pneumothorax, and is often normal in the setting of acute PE [1]. - Findings associated with PE (like **Westermark's sign** or **Hampton hump**) are often subtle, non-specific, and lack the sensitivity required to confirm the diagnosis [1].

Question 1

Patient came with severe headache and seizures. Sodium on admission was 98 meq/L. We have started correction with 3 % saline and now after 24 hours of infusion sodium is 110 meq/L. Patient develops mutism and altered sensorium. Which investigation will you perform now?

Accepted Answer

MRI Head

Answer

LP for CSF biochemistry

Answer

EEG

Answer

Brainstem evoked potentials

Question 2

A 30-year-old man with 6 month past history of PND and SOB. On examination, JVP is elevated with irregularly irregular pulse and tender hepatomegaly and MDM. past medical history of ARF. Which of the following is not seen in this patient?

Accepted Answer

Presystolic accentuation of mid-diastolic murmur is hallmark feature

Answer

Right heart failure

Answer

Absent a wave in JVP

Answer

Patient has increased risk of embolic stroke

Question 3

A 68-year-old male with a history of COPD presents to the emergency room with severe dyspnea and altered mental status. An arterial blood gas (ABG) is drawn with the following results:
pH: 7.28
PaCO2: 60 mmHg
HCO3-: 28 mEq/L
Na+: 142 mEq/L
Cl-: 100 mEq/L
Based on these results, what is the calculated anion gap?

Accepted Answer

B. 14 mEq/L

Answer

A. 10 mEq/L

Answer

D. 24 mEq/L

Answer

C. 18 mEq/L

Question 4

Based on the image provided, what is the most appropriate confirmatory investigation?

Accepted Answer

Manometry

Answer

Barium swallow study

Answer

Upper GI Endoscopy

Answer

pH monitoring

Question 5

A patient presents with palpitations and an irregularly irregular pulse. He presents within 2 hours of symptom onset, and has no history of diabetes or other comorbidities. What is the most appropriate initial management?

Accepted Answer

Cardioversion

Answer

Control ventricular rate with verapamil

Answer

TEE for starting anticoagulation

Answer

Wait and watch

Question 6

A patient presents with sudden onset aphasia and right sided arm weakness for past 4 hours. Which of the following investigations will be done to determine etiology of this case presentation?

Accepted Answer

Transesophageal echocardiography

Answer

Transthoracic echocardiography

Answer

MRI brain

Answer

Carotid doppler

Question 7

A patient presents with salt wasting, craving, hyperkalemia, metabolic acidosis, and skin pigmentation. What is the most likely diagnosis?

Accepted Answer

Addison's disease

Answer

Pheochromocytoma

Answer

Cushing's syndrome

Answer

Conn's syndrome

Question 8

A known type 1 diabetic presents with glucose 799 mg/dL, Na+ 128 mEq/L, Cl- 88 mEq/L, and signs of dehydration. Which of the following is NOT used in the initial management?

Accepted Answer

3 % Saline

Answer

0.9 % Normal saline

Answer

Potassium monitoring

Answer

IV infusion insulin

Question 9

A 55-year-old man presents with altered sensorium and deep labored breathing. ABG is given below. What is the most likely acid-base disorder?
pH: 7.20
pCO₂: 31 mmHg
HCO₃⁻:16 mEq/L
Na⁺: 130 mEq/L
Cl⁻: 84 mEq/L
PaO₂: 80 mmHg

Accepted Answer

Metabolic acidosis

Answer

Respiratory acidosis

Answer

Respiratory alkalosis

Answer

Metabolic alkalosis

Question 10

Old man underwent joint replacement surgery 3 days ago. Today he develops SOB with chest pain. O/E : pulse 100/min, BP 100/70 mm Hg, RR28/min and sp02: 85% room air. D-dimer is elevated. Which is the next best test

Accepted Answer

CTPA

Answer

CXR

Answer

ECG

Answer

V/Q scan

NEET-PG 2025 — Internal Medicine