NEET-PG 2021 — Internal Medicine

Q: A patient presents with generalized and easy fatigability. He reports weakness while working in a factory with exposure to benzene. Which of the following conditions should be suspected in this patient?

Leukemia. ***Leukemia*** - **Benzene exposure** is a well-established risk factor for developing **leukemia**, particularly acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). - **Generalized fatigue** and **easy fatigability** are common symptoms of leukemia, resulting from anemia, bone marrow infiltration, and systemic effects of the disease. - Benzene is classified as a **Group 1 carcinogen** by IARC with strong evidence for leukemogenesis. *Aplastic Anemia* - While benzene exposure can cause **aplastic anemia** (bone marrow failure), this condition typically presents with **pancytopenia** and more severe symptoms including bleeding and infections. - However, given the occupational exposure and symptoms, **leukemia** remains the primary concern as it is more commonly associated with chronic benzene exposure. - Aplastic anemia from benzene is less common than benzene-induced leukemia. *Hepatocellular Carcinoma* - While benzene exposure can be **hepatotoxic**, it is not primarily associated with an increased risk of **Hepatocellular Carcinoma**. - Risk factors for hepatocellular carcinoma include **chronic viral hepatitis** (HBV, HCV) and **alcoholism**. *Carcinoma Gall Bladder* - There is **no significant association** between benzene exposure and the development of **gallbladder cancer**. - Risk factors for gallbladder cancer include **gallstones**, porcelain gallbladder, and chronic inflammation. *Urinary Bladder Cancer* - **Aromatic amines** and **anilines** (often found in dye, rubber, and chemical industries) are established causes of bladder cancer, not typically benzene itself. - While benzene is a carcinogen, **bladder cancer** is not considered a primary or strong association with its exposure. [Practice more Internal Medicine PYQs on OnCourse]

10 Previous Year Questions with Answers & Explanations

Questions

A patient presents with cold skin, fatigue, shortness of breath on exertion, and an enlarged liver. Upon examination, his jugular venous pressure (JVP) reveals a prominent "a" wave. What is the most likely cause of the elevated "a" wave in this patient?

A patient presents with generalized and easy fatigability. He reports weakness while working in a factory with exposure to benzene. Which of the following conditions should be suspected in this patient?

A female engineer works for 12-14 hours a day and reports consuming only fast food, with no vegetables or fruits in her diet. Her hemoglobin (Hb) count is $9 \mathrm{~g} / \mathrm{dL}$, and her mean corpuscular volume (MCV) is 120 fL . Peripheral smear (PS) shows the presence of macrocytes. What is the most likely diagnosis?

A known case of AIDS with a productive cough and fever is found to have consolidation in the right infrascapular area. Chest X-ray shows right lower lobe consolidation, and the CD4 count is 55 per microlitre. What is the most common cause of this presentation?

A 56-year-old patient developed excruciating chest discomfort in the past 72 hours, relieved by GTN spray. Troponin I is normal, and the ECG shows features of left ventricular hypertrophy (LVH) with T wave flattening. The patient is already on statins, aspirin, and metoprolol 50 mg . What is the next best step in management?

A 68-year-old male presents with cough, sputum production, bronchial breath sounds, respiratory rate of 20/min, urea of 44 mg/dl, and BP of 110/70 mmHg. What is the next step in management?

A patient presents with breathlessness and wheezing. Absolute eosinophil count is 500 cells/ $\mu \mathrm{L}$. Chest X-ray shows a miliary pattern. What is the most likely diagnosis?

A patient presents with breathing difficulty and generalized weakness. On auscultation, a middiastolic murmur with a prominent "a" wave is observed. What is the most likely diagnosis?

A patient presents with confusion, altered mental status, and unusual behavior. On examination, CNS features such as disorientation and lethargy are noted. Laboratory results reveal a urine osmolality of 1000 mOsm/kg and a plasma osmolality of 250 mOsm/kg. What is the most likely electrolyte imbalance?

Q10

30-year-old male, weighing 70 kg , presents with a serum sodium level of $120 \mathrm{mEq} / \mathrm{L}$. Calculate the total sodium deficit.

NEET-PG 2021 - Internal Medicine NEET-PG Practice Questions and MCQs

Question 1: A patient presents with cold skin, fatigue, shortness of breath on exertion, and an enlarged liver. Upon examination, his jugular venous pressure (JVP) reveals a prominent "a" wave. What is the most likely cause of the elevated "a" wave in this patient?

A. Tricuspid Stenosis (Correct Answer)
B. Mitral Stenosis
C. Tricuspid Regurgitation
D. Mitral Regurgitation
E. Pulmonary Stenosis

Explanation: ***Tricuspid Stenosis*** - A prominent "a" wave in the **JVP** indicates increased **right atrial pressure** during atrial contraction, which is characteristic of **tricuspid stenosis** due to resistance to blood flow from the right atrium to the right ventricle. - The symptoms of **cold skin**, **fatigue**, **shortness of breath on exertion**, and an **enlarged liver** are consistent with **right-sided heart failure** caused by tricuspid stenosis. - Among the valvular causes, tricuspid stenosis most directly causes a prominent "a" wave with associated right heart failure symptoms. *Mitral Stenosis* - **Mitral stenosis** primarily affects the **left atrium** and left ventricle, leading to pulmonary symptoms and, if severe, right heart failure. - It would typically cause a prominent "a" wave in the **pulmonary veins**, not directly in the JVP, although severe pulmonary hypertension could eventually lead to right ventricular overload. *Tricuspid Regurgitation* - **Tricuspid regurgitation** causes a large, prominent, and often **pulsatile "c-v" wave** in the JVP due to the reflux of blood into the right atrium during ventricular systole. - While it can cause right heart failure symptoms, it does not typically present with an isolated prominent "a" wave. *Mitral Regurgitation* - **Mitral regurgitation** primarily affects the **left side of the heart**, leading to symptoms related to left heart failure (e.g., pulmonary edema). - It does not directly cause an elevated "a" wave in the **JVP** unless there is severe, longstanding left-sided heart failure leading to secondary pulmonary hypertension and right heart failure. *Pulmonary Stenosis* - **Pulmonary stenosis** causes obstruction to right ventricular outflow, which can lead to a prominent "a" wave due to increased right atrial pressure. - However, pulmonary stenosis typically presents with a **systolic ejection murmur** at the left upper sternal border and may have signs of **RV hypertrophy** rather than the predominantly congestive symptoms seen here. - The clinical picture of hepatomegaly and signs of backward failure is more consistent with tricuspid stenosis than pulmonary stenosis.

Question 2: A patient presents with generalized and easy fatigability. He reports weakness while working in a factory with exposure to benzene. Which of the following conditions should be suspected in this patient?

A. Hepatocellular Carcinoma
B. Leukemia (Correct Answer)
C. Carcinoma Gall Bladder
D. Urinary Bladder Cancer
E. Aplastic Anemia

Explanation: ***Leukemia*** - **Benzene exposure** is a well-established risk factor for developing **leukemia**, particularly acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). - **Generalized fatigue** and **easy fatigability** are common symptoms of leukemia, resulting from anemia, bone marrow infiltration, and systemic effects of the disease. - Benzene is classified as a **Group 1 carcinogen** by IARC with strong evidence for leukemogenesis. *Aplastic Anemia* - While benzene exposure can cause **aplastic anemia** (bone marrow failure), this condition typically presents with **pancytopenia** and more severe symptoms including bleeding and infections. - However, given the occupational exposure and symptoms, **leukemia** remains the primary concern as it is more commonly associated with chronic benzene exposure. - Aplastic anemia from benzene is less common than benzene-induced leukemia. *Hepatocellular Carcinoma* - While benzene exposure can be **hepatotoxic**, it is not primarily associated with an increased risk of **Hepatocellular Carcinoma**. - Risk factors for hepatocellular carcinoma include **chronic viral hepatitis** (HBV, HCV) and **alcoholism**. *Carcinoma Gall Bladder* - There is **no significant association** between benzene exposure and the development of **gallbladder cancer**. - Risk factors for gallbladder cancer include **gallstones**, porcelain gallbladder, and chronic inflammation. *Urinary Bladder Cancer* - **Aromatic amines** and **anilines** (often found in dye, rubber, and chemical industries) are established causes of bladder cancer, not typically benzene itself. - While benzene is a carcinogen, **bladder cancer** is not considered a primary or strong association with its exposure.

Question 3: A female engineer works for 12-14 hours a day and reports consuming only fast food, with no vegetables or fruits in her diet. Her hemoglobin (Hb) count is $9 \mathrm{~g} / \mathrm{dL}$, and her mean corpuscular volume (MCV) is 120 fL . Peripheral smear (PS) shows the presence of macrocytes. What is the most likely diagnosis?

A. Folic acid deficiency (Correct Answer)
B. Combined Vitamin B12 and Folic acid deficiency
C. Iron deficiency anemia
D. Vitamin B12 deficiency
E. Anemia of chronic disease

Explanation: ***Folic acid deficiency*** - A **highly restrictive diet** lacking vegetables and fruits, combined with **macrocytic anemia** (Hb 9 g/dL, MCV 120 fL), strongly suggests folic acid deficiency. - Folic acid is essential for **DNA synthesis**, and its deficiency leads to impaired erythrocyte maturation, resulting in **large, immature red blood cells (macrocytes)**. - **Folate stores deplete within 3-4 months** of inadequate intake, making dietary deficiency clinically significant. - The patient's diet explicitly lacks **folate-rich foods** (green vegetables, fruits, legumes). *Vitamin B12 deficiency* - Also causes **macrocytic anemia** with identical hematological findings. - However, **Vitamin B12 is found in animal products** (meat, dairy, eggs), which are commonly present in fast food. - **B12 stores last 3-5 years**, so dietary deficiency takes much longer to develop unless there is **malabsorption** (pernicious anemia, gastrectomy). - No evidence of malabsorption or strict veganism in this case. *Combined Vitamin B12 and Folic acid deficiency* - While theoretically possible, the dietary history points more specifically to **folate deficiency**. - Combined deficiencies are more common in **severe malnutrition** or **malabsorption syndromes**. - Fast food typically contains adequate B12 from animal products. *Iron deficiency anemia* - Presents as **microcytic hypochromic anemia** with **low MCV** (<80 fL). - This patient has **macrocytic anemia** (MCV 120 fL), which directly contradicts iron deficiency. - Caused by **chronic blood loss** or inadequate iron intake, leading to small, pale RBCs. *Anemia of chronic disease* - Usually presents as **normocytic** or **mildly microcytic** anemia, not macrocytic. - While chronic stress and poor nutrition could contribute, the **high MCV (120 fL)** and **macrocytes** are inconsistent with this diagnosis. - Anemia of chronic disease typically has **normal to low MCV** and **normal RBC morphology** without macrocytosis.

Question 4: A known case of AIDS with a productive cough and fever is found to have consolidation in the right infrascapular area. Chest X-ray shows right lower lobe consolidation, and the CD4 count is 55 per microlitre. What is the most common cause of this presentation?

A. Staphylococcus aureus
B. Pneumocystis jirovecii
C. Streptococcus pneumoniae (Correct Answer)
D. Mycoplasma pneumoniae
E. Mycobacterium tuberculosis

Explanation: ***Streptococcus pneumoniae*** - Despite severe immunocompromise (CD4 count 55), **bacterial pneumonia**, especially **Streptococcus pneumoniae**, remains the most common cause of pneumonia in patients with AIDS. - The presentation of productive cough, fever, and focal consolidation on chest X-ray (**right lower lobe consolidation**) is typical for bacterial pneumonia. *Staphylococcus aureus* - While *Staphylococcus aureus* can cause pneumonia in AIDS patients, particularly those with IV drug use or recent hospitalization, it is **less common** than *Streptococcus pneumoniae*. - *S. aureus* pneumonia often presents with **abscess formation** or **necrotizing pneumonia**, which is not explicitly mentioned. *Pneumocystis jirovecii* - *Pneumocystis jirovecii* pneumonia (PJP) is a common opportunistic infection in AIDS patients with **CD4 counts below 200**, but it typically presents with **diffuse interstitial infiltrates** or **no consolidation** on chest X-ray. - The classic presentation is **dry cough**, progressive dyspnea, and hypoxia, rather than focal consolidation and productive sputum. *Mycoplasma pneumoniae* - *Mycoplasma pneumoniae* causes **"walking pneumonia"** and is characterized by a less severe cough, **fewer systemic symptoms**, and usually **interstitial or patchy infiltrates**, not frank consolidation. - It is also **less common** in immunocompromised patients with such a low CD4 count compared to typical bacterial pathogens. *Mycobacterium tuberculosis* - While tuberculosis is an important opportunistic infection in AIDS patients with **CD4 counts below 100**, it typically presents with **chronic symptoms** (weeks to months), night sweats, weight loss, and often **upper lobe cavitary disease** or **miliary pattern** on chest X-ray. - The **acute presentation** with productive cough and **focal lobar consolidation** is more consistent with bacterial pneumonia than TB.

Question 5: A 56-year-old patient developed excruciating chest discomfort in the past 72 hours, relieved by GTN spray. Troponin I is normal, and the ECG shows features of left ventricular hypertrophy (LVH) with T wave flattening. The patient is already on statins, aspirin, and metoprolol 50 mg . What is the next best step in management?

A. LMWH (Low Molecular Weight Heparin)
B. Increase beta blocker dose
C. IV NTG Drip
D. Add Clopidogrel (Correct Answer)
E. Arrange urgent coronary angiography

Explanation: ***Add Clopidogrel*** - The patient presents with **unstable angina** (chest discomfort relieved by GTN, normal troponin, and ECG changes indicative of ischemia) and is already on aspirin, statins, and a beta-blocker. - Adding **clopidogrel** (or another P2Y12 inhibitor) is crucial for **dual antiplatelet therapy (DAPT)**, which is a cornerstone in the management of unstable angina/NSTEMI to prevent further thrombotic events. - This is the **immediate next step** to optimize medical therapy before considering invasive strategies. *LMWH (Low Molecular Weight Heparin)* - While **anticoagulation** is important in acute coronary syndromes and would be appropriate to add, the question asks for the **next best step** given the patient's existing management. - LMWH would typically be added alongside DAPT, but establishing dual antiplatelet therapy takes priority. *Increase beta blocker dose* - The patient is already on metoprolol 50 mg, and while **titrating beta-blockers** is important for symptom control and reducing myocardial oxygen demand, the immediate priority in unstable angina is to address the underlying thrombotic process with DAPT. - Beta-blocker optimization can be done after ensuring adequate antiplatelet therapy. *IV NTG Drip* - **Intravenous nitroglycerin (IV NTG)** is used to relieve ongoing chest pain and reduce preload/afterload, especially in severe or refractory symptoms. - However, the patient's chest discomfort was already **relieved by GTN spray**, indicating that immediate pain control with IV NTG is not the most urgent next step compared to preventing further thrombotic events with DAPT. *Arrange urgent coronary angiography* - While **coronary angiography** is indicated in high-risk unstable angina, the immediate next step is to **optimize medical management** with dual antiplatelet therapy. - Angiography timing depends on risk stratification; in a stable patient already on aspirin, beta-blockers, and statins, adding clopidogrel first ensures optimal antiplatelet coverage before any invasive procedure. - Early invasive strategy (angiography within 24-72 hours) would be appropriate after medical stabilization.

Question 6: A 68-year-old male presents with cough, sputum production, bronchial breath sounds, respiratory rate of 20/min, urea of 44 mg/dl, and BP of 110/70 mmHg. What is the next step in management?

A. Admit in ICU without mechanical ventilation (MV)
B. Home treatment (Rx)
C. Admit in ICU with mechanical ventilation (MV)
D. Room admission (Correct Answer)
E. Observation in emergency department

Explanation: ***Room admission*** - The patient's **CURB-65 score** is **2** (one point for urea >7 mmol/L [44 mg/dL = 15.7 mmol/L] and one point for age ≥65 years), indicating **moderate mortality risk** and clear need for **hospital admission**. - **CURB-65 score of 2** mandates inpatient admission for monitoring, IV antibiotics if needed, and supportive care in a general medical ward. - While showing signs of respiratory infection, the vital signs are stable and do not meet criteria for ICU admission. *Admit in ICU without mechanical ventilation (MV)* - **ICU criteria** for pneumonia typically include severe respiratory failure, hemodynamic instability (shock requiring vasopressors), or impending organ dysfunction, which are not met. - The patient's respiratory rate (20/min) and blood pressure (110/70 mmHg) are within acceptable limits for a non-ICU setting. - CURB-65 score of 3-5 or presence of major severity criteria would warrant ICU consideration. *Home treatment (Rx)* - **CURB-65 score of 2** precludes outpatient management and requires hospital admission. - Outpatient treatment is only appropriate for CURB-65 scores of 0-1 in patients without other comorbidities. - Given the patient's age (68 years), elevated urea, and presence of **bronchial breath sounds** consistent with consolidative pneumonia, **hospital admission** is mandatory. *Admit in ICU with mechanical ventilation (MV)* - There is no indication of **severe respiratory distress** (e.g., severe hypoxemia with SpO2 <90% on high-flow oxygen, hypercapnia, or respiratory acidosis) that would necessitate immediate mechanical ventilation. - The respiratory rate of 20/min is normal, and there is no mention of altered mental status, severe tachypnea, or increased work of breathing. *Observation in emergency department* - While brief observation may be appropriate for borderline cases, a **CURB-65 score of 2** indicates the patient requires formal hospital admission rather than just ED observation. - The presence of consolidation (bronchial breath sounds) and elevated urea support the need for inpatient ward admission with monitoring and treatment.

Question 7: A patient presents with breathlessness and wheezing. Absolute eosinophil count is 500 cells/ $\mu \mathrm{L}$. Chest X-ray shows a miliary pattern. What is the most likely diagnosis?

A. Tropical pulmonary eosinophilia (Correct Answer)
B. Bronchial asthma
C. Miliary Tuberculosis (TB)
D. Hypersensitivity pneumonitis
E. Allergic bronchopulmonary aspergillosis (ABPA)

Explanation: ***Tropical pulmonary eosinophilia*** - This condition is characterized by **eosinophilia** (absolute eosinophil count >500 cells/µL), **respiratory symptoms** such as breathlessness and wheezing, and a **miliary pattern** on chest X-ray, all consistent with the patient's presentation. - It results from a **hypersensitivity reaction** to microfilariae from Wuchereria bancrofti or Brugia malayi in individuals living in endemic regions. *Bronchial asthma* - While bronchial asthma can cause **breathlessness** and **wheezing**, a miliary pattern on chest X-ray is **not typical**, nor is an eosinophil count of 500 cells/µL, though eosinophilia can occur. - Asthma is primarily a disease of reversible airway obstruction, often triggered by **allergens** or irritants. *Miliary Tuberculosis (TB)* - **Miliary TB** would present with a miliary pattern on chest X-ray and breathlessness, but it is typically associated with **low or normal eosinophil counts**, and wheezing is less common. - Fever, night sweats, and weight loss are also common symptoms of Miliary TB. *Hypersensitivity pneumonitis* - This condition involves inflammation of the lung alveoli due to inhalation of organic dusts or chemicals, causing **breathlessness** and, occasionally, wheezing, but **eosinophilia is not a primary feature**. - Chest X-ray findings can be diverse, but a **miliary pattern** is less specific than for tropical pulmonary eosinophilia. *Allergic bronchopulmonary aspergillosis (ABPA)* - ABPA can present with **eosinophilia**, **wheezing**, and respiratory symptoms, but chest X-ray typically shows **central bronchiectasis** and **fleeting infiltrates** rather than a miliary pattern. - It occurs in patients with asthma or cystic fibrosis and is characterized by **hypersensitivity to Aspergillus fumigatus**.

Question 8: A patient presents with breathing difficulty and generalized weakness. On auscultation, a middiastolic murmur with a prominent "a" wave is observed. What is the most likely diagnosis?

A. Mitral Regurgitation (MR)
B. Mitral Stenosis (MS)
C. Tricuspid Regurgitation (TR)
D. Tricuspid Stenosis (TS) (Correct Answer)
E. Pulmonary Stenosis (PS)

Explanation: ***Tricuspid Stenosis (TS)*** - A **middiastolic murmur** in the tricuspid area (usually left lower sternal border) along with a **prominent "a" wave** (due to increased right atrial pressure against a stenotic tricuspid valve) is pathognomonic for tricuspid stenosis. - The symptoms of **breathing difficulty** and **generalized weakness** can arise from reduced cardiac output and venous congestion characteristic of TS. *Mitral Regurgitation (MR)* - MR typically presents with a **holosystolic murmur** best heard at the apex and radiating to the axilla. - It does not characteristically produce a middiastolic murmur or a prominent "a" wave. *Mitral Stenosis (MS)* - MS causes a **diastolic rumble** with an **opening snap**, best heard at the apex, but it is not typically associated with a pronounced "a" wave in the jugular venous pulse unless there's associated pulmonary hypertension and right heart strain. - The murmur is usually localized to the apex, whereas tricuspid murmurs are typically heard from the lower left sternal border. *Tricuspid Regurgitation (TR)* - TR is characterized by a **holosystolic murmur** that increases with inspiration, heard at the left lower sternal border. - It typically causes a prominent **"v" wave** in the jugular venous pulse due to regurgitant flow into the right atrium, not a prominent "a" wave. *Pulmonary Stenosis (PS)* - PS presents with a **systolic ejection murmur** at the left upper sternal border (pulmonic area), not a diastolic murmur. - While it can cause right heart strain, it does not produce the characteristic middiastolic murmur or prominent "a" wave seen in tricuspid stenosis.

Question 9: A patient presents with confusion, altered mental status, and unusual behavior. On examination, CNS features such as disorientation and lethargy are noted. Laboratory results reveal a urine osmolality of 1000 mOsm/kg and a plasma osmolality of 250 mOsm/kg. What is the most likely electrolyte imbalance?

A. Hypokalemia
B. Hyperkalemia
C. Hyponatremia (Correct Answer)
D. Hypernatremia
E. Hypercalcemia

Explanation: ***Hyponatremia*** - The **low plasma osmolality** (250 mOsm/kg) combined with a **high urine osmolality** (1000 mOsm/kg) indicates that the kidneys are inappropriately concentrating urine despite diluted plasma, a hallmark finding in euvolemic hyponatremia. - **Confusion**, **altered mental status**, and **unusual behavior** are classic neurological symptoms associated with hyponatremia, particularly when it develops acutely or severely. *Hypokalemia* - **Hypokalemia** is characterized by low serum potassium and can cause muscle weakness, arrhythmias, and fatigue, but it does not directly explain the given plasma and urine osmolality findings. - The neurological symptoms described are not typical primary manifestations of hypokalemia. *Hyperkalemia* - **Hyperkalemia** involves high serum potassium, commonly leading to cardiac arrhythmias and muscle weakness. - The provided **osmolality values** are not consistent with a primary diagnosis of hyperkalemia. *Hypernatremia* - **Hypernatremia** is defined by high serum sodium and would present with **high plasma osmolality**, which contradicts the given plasma osmolality of 250 mOsm/kg. - While it can cause neurological symptoms, the osmolality findings rule it out. *Hypercalcemia* - **Hypercalcemia** can present with neurological symptoms including confusion and lethargy ("stones, bones, groans, and psychiatric overtones"). - However, hypercalcemia does not produce the characteristic **low plasma osmolality with high urine osmolality** pattern seen in this case.

Question 10: 30-year-old male, weighing 70 kg , presents with a serum sodium level of $120 \mathrm{mEq} / \mathrm{L}$. Calculate the total sodium deficit.

A. 630 mEq
B. 280 mEq
C. 420 mEq
D. 840 mEq (Correct Answer)
E. 1260 mEq

Explanation: ***840 mEq*** - The formula for calculating **total sodium deficit** is: **(Desired Na - Actual Na) × Total Body Water (TBW)**. - In a male, TBW is approximately **60% of body weight**. For a 70 kg male, **TBW = 0.6 × 70 kg = 42 L**. - With a desired sodium of **140 mEq/L** (normal) and actual sodium of **120 mEq/L**, the total deficit is: - **(140 - 120) × 42 = 20 × 42 = 840 mEq** - This represents the **complete calculated sodium deficit** needed to restore serum sodium to normal levels. - **Note:** In clinical practice, this entire deficit is NOT replaced rapidly. Typically, only **6-12 mEq/L increase per 24 hours** is recommended to prevent **osmotic demyelination syndrome**, but the question asks for the total calculated deficit. *630 mEq* - This value represents a **partial correction target**, corresponding to raising serum sodium to approximately **135 mEq/L** instead of 140 mEq/L: (135 - 120) × 42 = 630 mEq. - Alternatively, it equals about **75% of the total deficit** (840 × 0.75 = 630). - While this may reflect a practical clinical target, it does not answer the question which asks for the **total deficit**. *420 mEq* - This corresponds to raising serum sodium by **10 mEq/L** (10 × 42 = 420 mEq). - This represents the **maximum recommended increase in the first 24 hours** to prevent complications. - It is a safe initial correction amount but not the total calculated deficit. *280 mEq* - This represents an even smaller increment, roughly equivalent to raising serum sodium by **6-7 mEq/L**. - This would be an **ultra-conservative initial correction** for chronic hyponatremia. - It significantly underestimates the total sodium deficit. *1260 mEq* - This is an **overestimation** that might result from incorrectly using 100% body weight as TBW instead of 60%: (140 - 120) × 70 = 1400 mEq (close to this range). - Or from miscalculation using wrong formula components. - This exceeds the actual total sodium deficit.