FMGE 2025 - Internal Medicine Practice Questions

Q: A 58-year-old woman comes to the clinic for a routine follow-up. She has a history of mild hypertension, which is well-controlled with medication. She reports no symptoms such as palpitations, dizziness, or chest pain. Her ECG shows a prolonged PR interval of 0.24 seconds with regular 1:1 AV conduction and narrow QRS complexes. What is the most likely diagnosis based on these ECG findings?

First-Degree AV Block. ***First-Degree AV Block*** - This ECG demonstrates a fixed and prolonged **PR interval** that is greater than 0.20 seconds (more than 5 small squares), which is the defining characteristic of a first-degree AV block. - There is a consistent **1:1 conduction** between the atria and ventricles, meaning every P wave is followed by a QRS complex, distinguishing it from higher-degree blocks. *Second-Degree AV Block* - This condition is characterized by intermittently **non-conducted P waves**, resulting in 'dropped' QRS complexes, which are not present in this ECG. - It has two types: **Mobitz I (Wenckebach)** with progressive PR prolongation before a dropped beat, and **Mobitz II** with a constant PR interval before an unpredictable dropped beat. *Third-Degree AV Block* - Also known as complete heart block, this involves complete **AV dissociation**, where there is no relationship between P waves and QRS complexes. - On an ECG, P waves and QRS complexes would occur at their own independent, regular rates, which is contrary to the 1:1 conduction seen here. *Bundle Branch Block* - The primary feature of a bundle branch block is a **wide QRS complex** (≥0.12 seconds) due to delayed ventricular depolarization. - The QRS complex in this ECG is **narrow** (<0.12 seconds), which rules out a bundle branch block.

Q: A 35-year-old woman presents with fluctuating muscle weakness, especially affecting her speech and swallowing. Repetitive nerve stimulation shows a decremental response. Her blood tests are negative for acetylcholine receptor (AChR) antibodies. Which of the following antibodies is most likely responsible for her symptoms?

Anti-MuSK antibodies. Detailed clinical evaluation of myasthenia gravis reveals that anti-MuSK antibodies target Muscle-Specific Kinase (MuSK), essential for clustering AChR at the NMJ [1]. Their presence confirms the diagnosis of Myasthenia Gravis (MG) in patients who are seronegative for AChR antibodies, often presenting with prominent bulbar and facial weakness [1]. Anti-dsDNA antibodies are specific for Systemic Lupus Erythematosus (SLE), an autoimmune disease that primarily causes arthritis, renal disease, and malar rash [2]. Although SLE can cause myositis or neuropathy, it does not typically present with the isolated, fluctuating postsynaptic weakness characteristic of Myasthenia Gravis and the decremental response. Anti-thyroid peroxidase (TPO) antibodies are primary markers for Hashimoto's thyroiditis, leading to hypothyroidism; screening for associated autoimmune thyroid disease is recommended in MG patients [1]. Anti-Ro antibodies, characteristic of Sjögren's Syndrome and SLE [2], primarily involve sicca symptoms and occasionally present with myositis, but not the hallmark features of ocular or bulbar MG.

Q: Which electrolyte abnormality will lead to cardiac arrhythmia in patients with severe vomiting?

Hypokalemia. ***Hypokalemia*** - Severe vomiting leads to significant loss of gastric acid and subsequent volume depletion, often resulting in **metabolic alkalosis** and substantial **potassium** loss (due to renal compensation and direct GI loss) [1]. - **Hypokalemia** directly affects cardiac muscle repolarization, predisposing the patient to various arrhythmias, including **ventricular tachycardia** (e.g., *Torsades de pointes*) [2], [3]. *Hyponatremia* - While severe vomiting can cause hyponatremia (due to volume loss and inappropriate ADH release), symptomatic effects are primarily **neurological** (e.g., seizures, confusion), not typically cardiac arrhythmias [2]. - The effect on the heart tends to be mild unless the drop is very rapid and severe; it primarily influences **myocardial contractility** through fluid shifts [2]. *Hyperkalemia* - Hyperkalemia causes severe and characteristic ECG changes (tall, peaked T waves, broadened QRS, possible asystole), but it is **not associated** with severe vomiting, which typically causes **hypokalemia** [2]. - Hyperkalemia is more commonly seen in conditions like **renal failure** or acidosis [4]. *Hypocalcemia* - Hypocalcemia primarily affects the heart by causing **prolongation of the QT interval**, which can increase the risk of *Torsades de pointes*, similar to hypokalemia. - However, calcium losses from simple gastric vomiting are generally **not as dramatic** or primary as the potassium losses, making hypokalemia the most direct and common cause of arrhythmia in this specific clinical scenario [1].

Q: A farmer presents with fever and subconjunctival hemorrhage. The microscopic agglutination test is found to be positive. What is the diagnosis?

Leptospira. ***Leptospira***- The clinical presentation of fever in a patient with an occupation involving exposure to animal habitats (farmer), coupled with the classic finding of **subconjunctival hemorrhage** (conjunctival suffusion), highly suggests **Leptospirosis** (Weil's disease) [1]. - The **Microscopic Agglutination Test (MAT)** is the gold standard serological test for the diagnosis of **Leptospirosis**, supporting this etiology [1]. *Brucella* - *Brucella* causes **Brucellosis** (Undulant Fever), characterized primarily by cyclical undulating fevers, night sweats, and localized infection (e.g., osteomyelitis or epididymitis), not typically subconjunctival hemorrhage. - Diagnosis usually involves blood culture or the Standard Tube Agglutination Test (SAT), not MAT. *E coli* - *E. coli* is a common cause of GI infections, UTIs, and sepsis; systemic *E. coli* disease does not typically manifest with the specific finding of subconjunctival hemorrhage. - MAT is not used for the diagnosis of *E. coli* infections, which are confirmed primarily through culture. *Staph aureus* - *S. aureus* can cause a wide range of infections (skin infections, endocarditis, sepsis) but is not associated with the specific syndrome presenting here (farmer, subconjunctival hemorrhage). - Diagnosis relies on culture, not serological tests like MAT, which is specific for spirochetes.

Q: A patient presents with fever, neck rigidity, headache, vomiting, and petechial rashes on the lower limbs. What is the most likely causative organism?

Neisseria meningitidis. ***Neisseria meningitidis***- This gram-negative diplococcus is the most likely causative agent as it classically causes **meningococcal meningitis** combined with **meningococcemia**, which highly correlates with the presence of **petechial or purpuric rashes** on the skin.- The rash results from **endotoxin** (lipooligosaccharide) damage to the blood vessel walls, leading to **vasculitis** and hemorrhage, often progressing to severe complications like the **Waterhouse-Friderichsen syndrome**.*Clostridium perfringens*- This organism is primarily known for causing **gas gangrene** (myonecrosis) and tissue necrosis, often following severe trauma or surgery.- It is not a common cause of primary community-acquired bacterial meningitis, and its clinical presentation focuses on localized **soft tissue infection** rather than systemic meningoencephalitis.*Cryptococcus neoformans*- This is a **fungal pathogen** that causes meningitis, usually in patients with **severe immunosuppression** (e.g., uncontrolled HIV infection).- Although it causes fever and signs of meningeal irritation, the presentation is typically subacute or chronic, and a hemorrhagic rash is not a standard clinical feature.*Clostridium difficile*- This bacterium is the causative agent of **antibiotic-associated diarrhea** and **pseudomembranous colitis**.- Its effects are localized almost exclusively to the colon, and it does not cause acute bacterial meningitis with systemic rash.

Q: A patient reports difficulty switching between movements and experiences uncontrollable hand movements. What is the most likely diagnosis?

Dysdiadochokinesis. ***Dysdiadochokinesis***- This term refers to the impairment in the ability to perform **rapid alternating movements**, directly matching the complaint of "difficulty switching between movements" [2].- It is a classic sign of **cerebellar dysfunction**, which also accounts for the associated **uncontrollable movements** (often reflecting associated **ataxia** or **dysmetria**) [3].*Intentional Tremor*- This tremor is absent at rest, but its amplitude increases significantly as the patient attempts to reach a **visual target** (e.g., during the finger-to-nose test).- While it is a sign of **cerebellar disease**, the primary complaint in the stem is difficulty *switching* movements, which is characteristic of **dysdiadochokinesis**.*Metamorphosis*- This neurological term typically refers to **perceptual distortion** (specifically, *metamorphopsia* is the distortion of visual size or shape), which is unrelated to motor control or coordination.- It is not the term used to describe the inability to perform **rapid alternating movements** or uncontrolled movements due to cerebellar pathology.*Resting Tremor*- A resting tremor is maximal when the limb is completely relaxed and **supported against gravity**, classically seen in **Parkinson's disease** [1].- This tremor usually **improves significantly** or disappears entirely when the patient performs voluntary action, distinguishing it from intentional tremors and general lack of coordination.

Q: A hypertensive patient’s lab results reveal hypernatremia, hypokalemia, and metabolic alkalosis. What is the most probable diagnosis?

Conn's Syndrome. ***Conn's Syndrome***- This condition, known as primary **hyperaldosteronism**, is defined by autonomous overproduction of aldosterone, leading to volume expansion and **hypertension** [1].- Aldosterone acts on the principal cells of the collecting duct to increase Na+ reabsorption (causing hypernatremia) while simultaneously promoting K+ and H+ excretion (causing **hypokalemia** and **metabolic alkalosis**) [2].*Addison’s Disease*- Addison’s disease is primary adrenal insufficiency, characterized by deficiency of mineralocorticoids and glucocorticoids [3].- This lack of aldosterone leads to impaired Na+ reabsorption and deficient K+ excretion, resulting in **hyponatremia** and **hyperkalemia** (the opposite of the clinical picture).*Diabetes Insipidus*- Diabetes Insipidus (DI) is a disorder of insufficient ADH action, resulting in polyuria and profound free water loss leading to **hypernatremia**.- DI does not arise from mineralocorticoid dysfunction, thus it would not typically cause **hypokalemia** or metabolic alkalosis.*Cushing's Disease*- Cushing's disease involves excess **cortisol** (a glucocorticoid), which can cause hypertension and occasionally hypokalemia.- However, the combination of **hypernatremia**, significant **hypokalemia**, and severe **metabolic alkalosis** strongly points toward primary **mineralocorticoid excess** rather than glucocorticoid excess [1].

Q: A patient presents with a history of vomiting. Arterial blood gas analysis reveals the following: - pH: 7.5 - pCO₂: 48 mm Hg - HCO₃⁻: 30 mEq/L What is the most likely acid-base abnormality?

Metabolic alkalosis. ***Metabolic alkalosis***- The high pH (7.5) indicates **alkalemia**, while the elevated **bicarbonate (HCO₃⁻)** of 30 mEq/L identifies the primary metabolic cause [3].- The mild elevation in **pCO₂ (48 mm Hg)** shows appropriate respiratory compensation via **hypoventilation**, attempting to normalize the pH [1, 2]. *Metabolic acidosis*- Requires a low **HCO₃⁻** level (< 22 mEq/L) and a low pH (< 7.35), directly contradicting the observed **high pH** (7.5) and high HCO₃⁻.- This state often arises from conditions like **lactic acidosis** or **diabetic ketoacidosis**, which are not supported by these blood gas results [4]. *Respiratory acidosis*- While the **pCO₂ is elevated (48 mm Hg)**, if this were the primary disorder, it would drive the pH toward an **acidemic** state (< 7.35), which is inconsistent with the pH of 7.5 [3].- Elevated pCO₂ in the context of alkalemia indicates that the respiratory change is a secondary, **compensatory response** to the primary metabolic alkalosis [1]. *Respiratory alkalosis*- This condition is characterized by a low **pCO₂** (< 35 mm Hg) leading to alkalemia, typically due to **hyperventilation** [1].- This diagnosis is ruled out because the patient’s pCO₂ is significantly elevated (48 mm Hg), not low.

Q: A patient with a history of Graves' disease underwent I-131 ablation therapy. Which of the following is the most likely long-term side effect of this treatment?

Hypothyroidism. ***Hypothyroidism*** - The primary mechanism of **I-131 ablation** is the destruction of functional thyroid tissue by radiation, leading to a permanent reduction in hormone production. - **Hypothyroidism** is the most common and often inevitable long-term complication following successful **radioiodine ablation** for conditions like Graves' disease or thyroid cancer, occurring in 80-90% of patients within the first year [1]. - Requires lifelong thyroid hormone replacement therapy. *Acute Thyroiditis* - This is a possible immediate side effect, known as **radiation thyroiditis**, causing transient local pain and tenderness within days to weeks of treatment. - It is a short-term inflammatory response due to radiation-induced thyroid cell damage, not the defining long-term side effect [1]. - Usually self-limiting and managed with NSAIDs or corticosteroids. *Hyperthyroidism* - Although an initial transient surge of thyroid hormones (due to tissue destruction releasing stored hormone) can occur within the first 1-2 weeks after I-131, this is temporary [2]. - The treatment's primary purpose is to permanently cure hyperthyroidism by destroying thyroid tissue. - Persistent or recurrent hyperthyroidism would indicate treatment failure, not a side effect. *Thyroid Storm* - A **thyroid storm** is an acute, life-threatening exacerbation of hyperthyroidism usually precipitated by factors like infection, surgery, or trauma [2]. - While extremely rare, radioiodine therapy can theoretically precipitate a storm in inadequately prepared, severely hyperthyroid patients [2]. - This is **not a likely or common side effect** compared to permanent hypothyroidism, and proper pre-treatment with antithyroid drugs minimizes this risk.

Q: In the context of mitral stenosis, which clinical feature is typically observed?

Loud S1. ***Loud S1*** - Mitral stenosis keeps the mitral leaflets in an open position until late diastole, resulting in an **abrupt and forceful closure** at the onset of systole, producing an abnormally loud S1. - This loud, snapping S1 is one of the **classic auscultatory findings** in non-calcific, mobile mitral stenosis. - The intensity of S1 correlates with valve mobility; as the valve becomes more calcified and immobile, S1 becomes softer. *Absent S1* - An absent or soft S1 indicates a **severely calcified, immobile mitral valve** (very advanced stenosis) or significant mitral regurgitation. - In early to moderate mitral stenosis, the valve leaflets remain mobile enough to generate a loud closure sound. - Loss of S1 intensity suggests progression to severe, end-stage valvular disease. *S3 gallop* - An S3 gallop is a sign of **rapid ventricular filling** caused by volume overload, typically heard in left ventricular systolic heart failure or significant mitral regurgitation. - Since mitral stenosis **restricts diastolic filling** into the left ventricle, an S3 is generally not heard in pure, isolated mitral stenosis. - The presence of S3 in a patient with MS should raise suspicion for coexistent left ventricular dysfunction or mixed valvular disease. *Muffled heart sounds* - Muffled or distant heart sounds suggest pathologies that dampen sound conduction, such as **pericardial effusion**, severe obesity, or emphysema. - Mitral stenosis characteristically produces **accentuated sounds** (loud S1, opening snap, diastolic rumble) rather than muffled sounds. - The presence of muffled sounds should prompt evaluation for alternative or additional cardiac pathology.

Question 1

A 58-year-old woman comes to the clinic for a routine follow-up. She has a history of mild hypertension, which is well-controlled with medication. She reports no symptoms such as palpitations, dizziness, or chest pain. Her ECG shows a prolonged PR interval of 0.24 seconds with regular 1:1 AV conduction and narrow QRS complexes. What is the most likely diagnosis based on these ECG findings?

Accepted Answer

First-Degree AV Block

Answer

Third-Degree AV Block

Answer

Second-Degree AV Block

Answer

Bundle Branch Block

Question 2

A 35-year-old woman presents with fluctuating muscle weakness, especially affecting her speech and swallowing. Repetitive nerve stimulation shows a decremental response. Her blood tests are negative for acetylcholine receptor (AChR) antibodies. Which of the following antibodies is most likely responsible for her symptoms?

Accepted Answer

Anti-MuSK antibodies

Answer

Anti-TPO antibodies

Answer

Anti-dsDNA antibodies

Answer

Anti-Ro antibodies

Question 3

Which electrolyte abnormality will lead to cardiac arrhythmia in patients with severe vomiting?

Accepted Answer

Hypokalemia

Answer

Hyponatremia

Answer

Hyperkalemia

Answer

Hypocalcemia

Question 4

A farmer presents with fever and subconjunctival hemorrhage. The microscopic agglutination test is found to be positive. What is the diagnosis?

Accepted Answer

Leptospira

Answer

Brucella

Answer

E coli

Answer

Staph aureus

Question 5

A patient presents with fever, neck rigidity, headache, vomiting, and petechial rashes on the lower limbs. What is the most likely causative organism?

Accepted Answer

Neisseria meningitidis

Answer

Cryptococcus neoformans

Answer

Clostridium difficile

Answer

Clostridium perfringens

Question 6

A patient reports difficulty switching between movements and experiences uncontrollable hand movements. What is the most likely diagnosis?

Accepted Answer

Dysdiadochokinesis

Answer

Metamorphosis

Answer

Resting Tremor

Answer

Intentional Tremor

Question 7

A hypertensive patient’s lab results reveal hypernatremia, hypokalemia, and metabolic alkalosis. What is the most probable diagnosis?

Accepted Answer

Conn's Syndrome

Answer

Addison’s Disease

Answer

Cushing's Disease

Answer

Diabetes Insipidus

Question 8

A patient presents with a history of vomiting. Arterial blood gas analysis reveals the following: - pH: 7.5 - pCO₂: 48 mm Hg - HCO₃⁻: 30 mEq/L What is the most likely acid-base abnormality?

Accepted Answer

Metabolic alkalosis

Answer

Respiratory acidosis

Answer

Respiratory alkalosis

Answer

Metabolic acidosis

Question 9

A patient with a history of Graves' disease underwent I-131 ablation therapy. Which of the following is the most likely long-term side effect of this treatment?

Accepted Answer

Hypothyroidism

Answer

Thyroid Storm

Answer

Hyperthyroidism

Answer

Acute Thyroiditis

Question 10

In the context of mitral stenosis, which clinical feature is typically observed?

Accepted Answer

Loud S1

Answer

S3 gallop

Answer

Muffled heart sounds

Answer

Absent S1

FMGE 2025 — Internal Medicine