A female presents with a 1 × 1 cm thyroid swelling. What is the next best step in management?
Q2
What is the most appropriate initial investigation for a solitary thyroid nodule (STN)?
Q3
A young patient presents to the OPD with recurrent colicky abdominal pain. Urine examination shows the presence of red blood cells (RBCs) and the following crystal shape in the figure. What is the most likely diagnosis?
Q4
An 11-year-old boy is brought to the emergency department 30 minutes after he was found screaming and clutching his head. He has had nausea and occasional episodes of vomiting for 1 week, fever and left-sided headaches for 2 weeks, and increasing tooth pain over the past 3 weeks. He has no history of ear or sinus infections. He is in moderate distress. His temperature is 38.7°C (101.7°F), pulse is 170/min, respirations are 19/min, and blood pressure is 122/85 mmHg. He is confused and only oriented to person. The pupils react sluggishly to light. Fundoscopic examination shows papilledema bilaterally. Extraocular movements are normal. Flexion of the neck causes hip flexion. Which of the following is the most likely diagnosis?
Q5
A 70-year-old man is brought to the emergency department for the evaluation of worsening upper abdominal pain that he first noticed this morning after waking up. The pain is of tearing and burning quality and radiates to his back. Yesterday, he underwent an upper endoscopy and was diagnosed with gastritis and a large hiatal hernia. He has hypertension, hypercholesteremia, and a left bundle branch block that was diagnosed 5 years ago. The patient's mother died of myocardial infarction at the age of 70 years, and his father died of aortic dissection at the age of 65 years. The patient smoked one pack of cigarettes daily for the past 40 years, but quit 10 years ago. He drinks three beers daily. Current medications include hydrochlorothiazide, amlodipine, atorvastatin, and pantoprazole. The patient appears to be in mild distress. His temperature is 37.8°C (100.4°F), pulse is 103/min, and blood pressure is 135/89 mm Hg in the left arm and 132/90 mm Hg in the right arm. Cardiopulmonary examination shows crackling with every heartbeat. Abdominal examination shows tenderness to palpation in the epigastric region; bowel sounds are normal. Laboratory studies show:
Hemoglobin 16.0 g/dL
Leukocyte count 11,000/mm3
Na+ 140 mEq/L
K+ 4.2 mEq/L
Cl- 101 mEq/L
HCO3- 25 mEq/L
Creatinine 1.3 mg/dL
Alanine aminotransferase 21 U/L
Aspartate aminotransferase 43 U/L
Lipase 40 U/L (N = 14–280)
Troponin I 0.025 ng/mL (N < 0.1)
Chest x-ray shows a large hiatal hernia and mediastinal lucency. A 12-lead EKG shows sinus tachycardia and a left bundle branch block. Which of the following is the most appropriate next step in diagnosis?
Q6
A 43-year-old woman was admitted to the hospital after a fall. When the emergency services arrived, she was unresponsive, did not open her eyes, but responded to painful stimuli. The witnesses say that she had convulsions lasting about 30 seconds when she lost consciousness after a traumatic event. On her way to the hospital, she regained consciousness. On admission, she complained of intense headaches and nausea. She opened her eyes spontaneously, was responsive but confused, and was able to follow motor commands. Her vital signs are as follows: blood pressure, 150/90 mm Hg; heart rate, 62/min; respiratory rate, 13/min; and temperature, 37.3℃ (99.1℉). There are no signs of a skull fracture. The pupils are round, equal, and poorly reactive to light. She is unable to fully abduct both eyes. Ophthalmoscopy does not show papillary edema or retinal hemorrhages. She has nuchal rigidity and a positive Kernig sign. An urgent head CT does not show any abnormalities. Which of the following is a proper investigation to perform in this patient?
Q7
A 52-year-old woman comes to the emergency department because of a 3-hour history of right flank pain and nausea. Her only medication is a multivitamin. Her vital signs are within normal limits. Physical examination shows tenderness in the right costovertebral angle. Urinalysis shows a pH of 5.1, 50–60 RBC/hpf, and dumbbell-shaped crystals. Which of the following best describes the composition of the crystals seen on urinalysis?
Q8
A 21-year-old college student is brought to the emergency department in a state of confusion. He also had one seizure approx. 45 minutes ago. He was complaining of fever and headache for the past 3 days. There was no history of nausea, vomiting, head trauma, sore throat, skin rash, or abdominal pain. Physical examination reveals: blood pressure 102/78 mm Hg, heart rate 122/min, and temperature 38.4°C (101.2°F). The patient is awake but confused and disoriented. He is sensitive to light and loud noises. Heart rate is elevated with a normal rhythm. Lungs are clear to auscultation bilaterally. The fundus examination is benign. Brudzinski’s sign is positive. What is the next best step in the management of this patient?
Q9
A 45-year-old woman undergoes endoscopic retrograde cholangiopancreatography (ERCP) for evaluation of suspected biliary strictures. The ERCP identifies 2 ducts in the pancreas (a small ventral duct and a larger dorsal duct). A diagnosis of a congenital pancreatic anomaly is made. Which of the following statements best describes this anomaly?
Q10
A 24-year-old female presents to her primary care physician with right knee pain for the last week. She states that she first noticed it after a long flight on her way back to the United States from Russia, where she had run a marathon along a mountain trail. The patient describes the pain as dull, aching, and localized to the front of her kneecap, and it worsens with sitting but improves with standing. Aspirin has not provided significant relief. The patient has a history of a torn anterior cruciate ligament (ACL) on the right side from a soccer injury three years ago. In addition, she was treated for gonorrhea last month after having intercourse with a new partner. At this visit, the patient’s temperature is 98.5°F (36.9°C), blood pressure is 112/63 mmHg, pulse is 75/min, and respirations are 14/min. Which of the following is most likely to establish the diagnosis?
Differential diagnosis US Medical PG Practice Questions and MCQs
Question 1: A female presents with a 1 × 1 cm thyroid swelling. What is the next best step in management?
A. I-131
B. TSH (Correct Answer)
C. TSH & T4
D. T3 & T4
E. FNAC
Explanation: ***Correct Option: TSH***
- **Thyroid-stimulating hormone (TSH)** is the most sensitive initial test to assess thyroid function when a thyroid nodule is discovered.
- An abnormal TSH level (either high or low) can guide further investigation into whether the nodule is associated with a functional thyroid disorder.
- **TSH should be the first test** according to American Thyroid Association guidelines for thyroid nodule evaluation.
*Incorrect Option: I-131*
- **I-131 (radioactive iodine therapy)** is a treatment modality for hyperthyroidism or thyroid cancer, not a diagnostic step for initial thyroid swelling evaluation.
- Administering I-131 before assessing thyroid function would be inappropriate and could lead to unnecessary or harmful intervention.
*Incorrect Option: TSH & T4*
- While TSH is crucial, adding **T4 (thyroxine)** as an initial step is often not necessary if TSH is normal, as TSH alone effectively screens for primary thyroid dysfunction.
- Measuring both TSH and T4 is typically reserved for situations where TSH is abnormal or when central hypothyroidism is suspected.
*Incorrect Option: T3 & T4*
- Measuring **T3 (triiodothyronine)** along with T4 as an initial screening for a thyroid nodule is generally not recommended.
- T3 levels are primarily used to diagnose **hyperthyroidism** or to evaluate the severity of thyrotoxicosis after an abnormal TSH and T4 have been identified.
*Incorrect Option: FNAC*
- While **Fine Needle Aspiration Cytology (FNAC)** is an essential diagnostic tool for thyroid nodules, it is typically performed after TSH assessment.
- FNAC is indicated for nodules >1 cm with suspicious ultrasound features, but **functional assessment with TSH comes first** to rule out hyperfunctioning nodules.
Question 2: What is the most appropriate initial investigation for a solitary thyroid nodule (STN)?
A. I-123 scan
B. Ultrasound (Correct Answer)
C. Fine-needle aspiration (FNA) biopsy
D. Thyroid function tests (TFTs)
E. CT scan of the neck
Explanation: ***Ultrasound***
- **Ultrasound** is the initial investigation of choice for a solitary thyroid nodule (STN) because it can differentiate between **solid, cystic, or mixed lesions**, assess nodule size, and identify suspicious features (e.g., microcalcifications, irregular margins, internal vascularity).
- It also helps to determine if there are other nodules not palpable on physical examination, allowing for a more complete assessment of the **thyroid gland**.
*Fine-needle aspiration (FNA) biopsy*
- **FNA biopsy** is the most accurate diagnostic tool for evaluating the malignant potential of a thyroid nodule, but it is typically performed *after* an initial ultrasound has characterized the nodule.
- It requires guidance (often by ultrasound) to obtain an adequate sample for cytological analysis, making ultrasound a prerequisite for optimal FNA performance.
*Thyroid function tests (TFTs)*
- **TFTs (TSH, T3, T4)** are important for assessing the functional status of the thyroid gland (e.g., hyperthyroidism or hypothyroidism) and can provide context for the nodule.
- However, TFTs do not directly evaluate the **morphology or malignant potential** of the nodule itself, making them less appropriate as an initial, stand-alone investigation for an STN.
*I-123 scan*
- An **I-123 scan** (radioactive iodine uptake and scan) is used to determine if a nodule is "hot" (hyperfunctioning/benign) or "cold" (non-functioning/potentially malignant).
- It is typically reserved for cases where **TSH levels are suppressed**, suggesting a hyperfunctioning nodule, and is not the first-line imaging modality for initial characterization of all STNs.
*CT scan of the neck*
- **CT scan** can visualize thyroid nodules and assess for extrathyroidal extension or lymphadenopathy, but it is **not recommended as an initial investigation** for STN.
- It involves **radiation exposure**, is more expensive than ultrasound, and provides **less detailed characterization** of nodule morphology compared to ultrasound, making it a less appropriate first-line modality.
Question 3: A young patient presents to the OPD with recurrent colicky abdominal pain. Urine examination shows the presence of red blood cells (RBCs) and the following crystal shape in the figure. What is the most likely diagnosis?
A. Cystine stone (Correct Answer)
B. Glomerulonephritis
C. Oxalate stone
D. Polycystic kidney disease
E. Uric acid stone
Explanation: ***Cystine stone***
- The image displays classic **hexagonal** crystals, which are pathognomonic for **cystine stones**.
- Recurrent colicky abdominal pain in a young patient with hematuria (RBCs in urine) is highly suggestive of **nephrolithiasis** (kidney stones), and the crystal morphology confirms cystine as the cause.
- Cystine stones are associated with **cystinuria**, an autosomal recessive disorder causing defective renal tubular reabsorption of cystine.
*Glomerulonephritis*
- While glomerulonephritis can cause hematuria, the presence of **hexagonal crystals** in the urine is not a feature of this condition.
- Glomerulonephritis typically involves **dysmorphic RBCs** and **RBC casts** in the urine, not hexagonal crystals.
*Oxalate stone*
- **Calcium oxalate crystals** typically appear as **envelope-shaped (dihydrate)** or **dumbbell-shaped (monohydrate)**.
- While oxalate stones are the most common cause of kidney stones and colicky pain, their crystal morphology is distinct from the hexagonal shape seen here.
*Polycystic kidney disease*
- Polycystic kidney disease is a genetic disorder characterized by **multiple cysts** in the kidneys, which can cause pain and hematuria.
- However, it does **not** typically present with specific crystal shapes like those shown in the image, as the primary pathology is structural, not related to crystal formation.
*Uric acid stone*
- **Uric acid crystals** typically appear as **rhomboid or diamond-shaped** crystals, often with a yellow-brown color.
- While uric acid stones can cause similar symptoms (colicky pain, hematuria), the crystal morphology is distinctly different from the hexagonal cystine crystals shown in the image.
- Uric acid stones are associated with **hyperuricemia**, **low urine pH**, and conditions like gout.
Question 4: An 11-year-old boy is brought to the emergency department 30 minutes after he was found screaming and clutching his head. He has had nausea and occasional episodes of vomiting for 1 week, fever and left-sided headaches for 2 weeks, and increasing tooth pain over the past 3 weeks. He has no history of ear or sinus infections. He is in moderate distress. His temperature is 38.7°C (101.7°F), pulse is 170/min, respirations are 19/min, and blood pressure is 122/85 mmHg. He is confused and only oriented to person. The pupils react sluggishly to light. Fundoscopic examination shows papilledema bilaterally. Extraocular movements are normal. Flexion of the neck causes hip flexion. Which of the following is the most likely diagnosis?
A. Subarachnoid hemorrhage
B. Cavernous sinus thrombosis
C. Pyogenic brain abscess (Correct Answer)
D. HSV encephalitis
E. Medulloblastoma
Explanation: ***Pyogenic brain abscess***
- The patient's history of **increasing tooth pain** over three weeks, followed by fever, headache, nausea, vomiting, confusion, and **papilledema**, strongly suggests a pyogenic brain abscess originating from a dental infection.
- **Brudzinski's sign** (nuchal rigidity with **hip flexion upon neck flexion**) indicates meningeal irritation, and confusion with sluggish pupillary reaction are signs of increased intracranial pressure, consistent with an expanding mass lesion and inflammation.
*Subarachnoid hemorrhage*
- While it can cause sudden severe headache ("thunderclap"), nausea, vomiting, and meningeal signs, the **subacute onset** of symptoms (weeks) and the presence of prior dental pain make this diagnosis less likely.
- **Fever** with prolonged, progressive symptoms and signs of focal neurological deficits (which can be subtle like confusion and sluggish pupils) are not typical for SAH.
*Cavernous sinus thrombosis*
- This condition is typically associated with infections in the facial region or sinuses, leading to **ophthalmoplegia**, **proptosis**, and chemosis due to involvement of cranial nerves III, IV, VI, and the ophthalmic/maxillary branches of V.
- Although the patient has headache and fever, the absence of specific ocular signs like paralysis of extraocular muscles or proptosis makes this less probable.
*HSV encephalitis*
- While HSV encephalitis can cause fever, headache, altered mental status, and seizures, its onset is typically **acute to subacute** (days), and it often presents with **focal neurological deficits** or personality changes, not typically originating from dental pain.
- The preceding tooth pain and the relatively prolonged symptom timeline (weeks) are less characteristic of primary HSV encephalitis.
*Medulloblastoma*
- This is a common posterior fossa tumor in children, which can cause symptoms of increased ICP like headache, nausea, vomiting, and papilledema due to hydrocephalus.
- However, the presence of **fever** and a clear preceding **infectious source** (dental pain) points away from a primary tumor and more towards an infectious process like an abscess.
Question 5: A 70-year-old man is brought to the emergency department for the evaluation of worsening upper abdominal pain that he first noticed this morning after waking up. The pain is of tearing and burning quality and radiates to his back. Yesterday, he underwent an upper endoscopy and was diagnosed with gastritis and a large hiatal hernia. He has hypertension, hypercholesteremia, and a left bundle branch block that was diagnosed 5 years ago. The patient's mother died of myocardial infarction at the age of 70 years, and his father died of aortic dissection at the age of 65 years. The patient smoked one pack of cigarettes daily for the past 40 years, but quit 10 years ago. He drinks three beers daily. Current medications include hydrochlorothiazide, amlodipine, atorvastatin, and pantoprazole. The patient appears to be in mild distress. His temperature is 37.8°C (100.4°F), pulse is 103/min, and blood pressure is 135/89 mm Hg in the left arm and 132/90 mm Hg in the right arm. Cardiopulmonary examination shows crackling with every heartbeat. Abdominal examination shows tenderness to palpation in the epigastric region; bowel sounds are normal. Laboratory studies show:
Hemoglobin 16.0 g/dL
Leukocyte count 11,000/mm3
Na+ 140 mEq/L
K+ 4.2 mEq/L
Cl- 101 mEq/L
HCO3- 25 mEq/L
Creatinine 1.3 mg/dL
Alanine aminotransferase 21 U/L
Aspartate aminotransferase 43 U/L
Lipase 40 U/L (N = 14–280)
Troponin I 0.025 ng/mL (N < 0.1)
Chest x-ray shows a large hiatal hernia and mediastinal lucency. A 12-lead EKG shows sinus tachycardia and a left bundle branch block. Which of the following is the most appropriate next step in diagnosis?
A. Contrast esophagography with gastrografin (Correct Answer)
B. Contrast-enhanced CT of the aorta
C. Esophagogastroduodenoscopy
D. Abdominal ultrasound
E. Coronary angiography
Explanation: ***Contrast esophagography with gastrografin***
- The patient's symptoms (worsening abdominal pain after endoscopy, tearing/burning quality radiating to the back) and imaging findings (mediastinal lucency on chest x-ray, crackling with every heartbeat suggestive of **Hamman's sign**) are highly indicative of **esophageal perforation**.
- **Gastrografin** (water-soluble contrast) is the preferred initial study for suspected esophageal perforation because it is less irritating to the mediastinal tissues and can be reabsorbed if extravasated, unlike barium.
*Contrast-enhanced CT of the aorta*
- Although the patient has risk factors for **aortic dissection** (hypertension, family history), his symptoms are more classic for esophageal perforation, particularly after recent endoscopy.
- The **mediastinal lucency** on chest x-ray strongly suggests esophageal perforation rather than aortic dissection.
*Esophagogastroduodenoscopy*
- Repeating an **EGD** would be contraindicated and dangerous in a patient with suspected esophageal perforation as it could worsen the tear and lead to further mediastinal contamination.
- The initial EGD likely contributed to the current presumed perforation.
*Abdominal ultrasound*
- An abdominal ultrasound is useful for evaluating conditions like **cholecystitis**, **pancreatitis**, or abdominal aortic aneurysm, but it would not reliably detect an esophageal perforation.
- The patient's pain radiation and chest x-ray findings point away from these diagnoses.
*Coronary angiography*
- While the patient has cardiac risk factors and a family history of **myocardial infarction**, his **troponin I** is normal, and his pain description of tearing/burning quality radiating to the back is less typical for cardiac ischemia.
- The combined clinical picture and mediastinal lucency point strongly towards esophageal pathology.
Question 6: A 43-year-old woman was admitted to the hospital after a fall. When the emergency services arrived, she was unresponsive, did not open her eyes, but responded to painful stimuli. The witnesses say that she had convulsions lasting about 30 seconds when she lost consciousness after a traumatic event. On her way to the hospital, she regained consciousness. On admission, she complained of intense headaches and nausea. She opened her eyes spontaneously, was responsive but confused, and was able to follow motor commands. Her vital signs are as follows: blood pressure, 150/90 mm Hg; heart rate, 62/min; respiratory rate, 13/min; and temperature, 37.3℃ (99.1℉). There are no signs of a skull fracture. The pupils are round, equal, and poorly reactive to light. She is unable to fully abduct both eyes. Ophthalmoscopy does not show papillary edema or retinal hemorrhages. She has nuchal rigidity and a positive Kernig sign. An urgent head CT does not show any abnormalities. Which of the following is a proper investigation to perform in this patient?
A. Lumbar puncture (Correct Answer)
B. Angiography
C. Sonography
D. Brain MRI
E. EEG
Explanation: ***Lumbar puncture***
- The patient's symptoms, including **severe headache**, **nuchal rigidity**, **positive Kernig sign**, and **abnormal oculomotor findings** (poorly reactive pupils, inability to abduct eyes), despite a normal head CT, are highly suggestive of **subarachnoid hemorrhage**. A lumbar puncture is essential to look for **xanthochromia** (yellowish discoloration of CSF due to bilirubin from lysed red blood cells), which confirms the diagnosis, especially when CT is negative in the first 6-12 hours.
- The history of a "traumatic event" followed by convulsions and transient loss of consciousness, along with a "lucid interval" then renewed symptoms (headache, confusion), raises suspicion for head injury leading to hemorrhagic event. The **elevated BP and bradycardia** (Cushing's reflex components), though not fully developed, also suggest increased intracranial pressure, further warranting investigation for hemorrhage.
*Angiography*
- While angiography (CTA or conventional) is performed **after a subarachnoid hemorrhage is confirmed** to identify the source of bleeding (e.g., aneurysm), it is not the *initial* diagnostic test to *confirm* the hemorrhage itself when CT is negative.
- Doing an angiography before ruling out significant hemorrhage via LP (when CT is negative) is premature and could expose the patient to unnecessary risks without a confirmed diagnosis.
*Sonography*
- **Sonography** (ultrasound) has **no role** in the acute diagnosis of subarachnoid hemorrhage or other intracranial pathology in adults.
- It is used for imaging the brain in neonates through the open fontanelles but is ineffective through the adult skull.
*Brain MRI*
- While an **MRI is more sensitive than CT for detecting subarachnoid hemorrhage** (especially subacute hemorrhage or small bleeds missed by CT), it is generally **less readily available** in an emergency setting than CT and LP.
- In cases where CT is negative but clinical suspicion for SAH is high, **lumbar puncture is typically the next step** as it can detect early SAH via xanthochromia, which might not be immediately visible on MRI. MRI may be used later to identify causes or small bleeds not picked up by CT.
*EEG*
- An **EEG (electroencephalogram)** is used to **evaluate seizure activity** and other types of brain dysfunction related to electrical activity.
- While the patient had convulsions, the primary concern given her overall presentation (severe headache, meningeal signs, altered mental status, and cranial nerve palsies) is **subarachnoid hemorrhage**, not solely seizure. An EEG would not help diagnose the underlying cause of her acute neurological deterioration.
Question 7: A 52-year-old woman comes to the emergency department because of a 3-hour history of right flank pain and nausea. Her only medication is a multivitamin. Her vital signs are within normal limits. Physical examination shows tenderness in the right costovertebral angle. Urinalysis shows a pH of 5.1, 50–60 RBC/hpf, and dumbbell-shaped crystals. Which of the following best describes the composition of the crystals seen on urinalysis?
A. Calcium phosphate
B. Magnesium ammonium phosphate
C. Cystine
D. Ammonium urate
E. Calcium oxalate (Correct Answer)
Explanation: ***Calcium oxalate***
- The presence of **dumbbell-shaped crystals** in the context of **flank pain**, nausea, and **hematuria** is highly characteristic of calcium oxalate stones.
- While calcium oxalate crystals can also be Envelope (octahedral) shaped, the **dumbbell shape** is a common morphology found, particularly in calcium oxalate monohydrate.
*Calcium phosphate*
- Calcium phosphate crystals typically present in an **alkaline urine** (pH > 7.0), appearing as amorphous, stellate, or platelike shapes, not dumbbell-shaped.
- This patient's urine pH of 5.1 is **acidic**, making calcium phosphate less likely.
*Magnesium ammonium phosphate*
- Also known as **struvite crystals**, these are typically associated with **alkaline urine** and **urinary tract infections** caused by urea-splitting bacteria (e.g., *Proteus*).
- They appear as **coffin-lid shaped crystals** and are not dumbbell-shaped.
*Cystine*
- Cystine crystals are associated with a rare genetic disorder, **cystinuria**, and appear as characteristic **hexagonal plates** in acidic urine.
- They are not dumbbell-shaped.
*Ammonium urate*
- Ammonium urate crystals are typically observed in **alkaline urine** and have a characteristic **thorn apple** or spiky sphere appearance.
- This patient's urine pH is acidic, and the crystal morphology doesn't match.
Question 8: A 21-year-old college student is brought to the emergency department in a state of confusion. He also had one seizure approx. 45 minutes ago. He was complaining of fever and headache for the past 3 days. There was no history of nausea, vomiting, head trauma, sore throat, skin rash, or abdominal pain. Physical examination reveals: blood pressure 102/78 mm Hg, heart rate 122/min, and temperature 38.4°C (101.2°F). The patient is awake but confused and disoriented. He is sensitive to light and loud noises. Heart rate is elevated with a normal rhythm. Lungs are clear to auscultation bilaterally. The fundus examination is benign. Brudzinski’s sign is positive. What is the next best step in the management of this patient?
A. Intensive care unit referral
B. MRI of the brain
C. CT scan of the brain (Correct Answer)
D. Electroencephalography
E. Lumbar puncture
Explanation: ***CT scan of the brain***
- The patient presents with **altered mental status** (confusion, disorientation) and a **recent seizure**, which are **absolute indications for CT scan before lumbar puncture** according to IDSA guidelines.
- Even with a benign fundus examination, CT is necessary to rule out **increased intracranial pressure**, **mass lesions**, or **brain abscess** that could cause herniation during LP.
- In suspected meningitis with these risk factors, the standard approach is: **CT first → then LP if CT is safe** → empiric antibiotics if LP is delayed.
- This protects against the potentially fatal complication of **cerebral herniation** during lumbar puncture.
*Lumbar puncture*
- While lumbar puncture is **essential for diagnosing meningitis** and analyzing CSF, it must be performed safely.
- In patients with altered consciousness or seizures, **LP should be deferred until after CT** rules out contraindications.
- If LP is delayed, **empiric antibiotics** (e.g., ceftriaxone + vancomycin + acyclovir) should be started immediately after blood cultures.
*Intensive care unit referral*
- ICU referral may be appropriate after initial diagnostic workup and stabilization, or if the patient deteriorates rapidly.
- However, the **immediate next step** is to obtain neuroimaging before proceeding with LP to confirm the diagnosis.
*MRI of the brain*
- MRI provides superior detail for evaluating **encephalitis**, **brain abscess**, or other parenchymal pathology.
- However, **CT is faster and more readily available** in the emergency setting and is sufficient for ruling out LP contraindications.
- MRI may be obtained later for further characterization if needed.
*Electroencephalography*
- EEG evaluates seizure activity and can identify seizure foci or status epilepticus.
- While the patient had a seizure, the **primary concern is suspected meningitis**, which requires CSF analysis (after safe neuroimaging).
- EEG does not diagnose the underlying infectious cause and is not the immediate priority.
Question 9: A 45-year-old woman undergoes endoscopic retrograde cholangiopancreatography (ERCP) for evaluation of suspected biliary strictures. The ERCP identifies 2 ducts in the pancreas (a small ventral duct and a larger dorsal duct). A diagnosis of a congenital pancreatic anomaly is made. Which of the following statements best describes this anomaly?
A. Endoscopic ultrasonography reveals a 'stack sign' in patients with this condition
B. Patients with recurrent episodes of pancreatitis due to this condition do not require any intervention
C. It is the most common congenital anomaly of the pancreas
D. Magnetic resonance cholangiopancreatography (MRCP) scanning of the abdomen is the most sensitive non-invasive diagnostic technique for this condition (Correct Answer)
E. Most of the patients with this condition present in early childhood with abdominal symptoms
Explanation: ***Magnetic resonance cholangiopancreatography (MRCP) scanning of the abdomen is the most sensitive non-invasive diagnostic technique for this condition***
- **MRCP** is highly effective in visualizing the pancreatic ductal system, offering **non-invasive detection** of **pancreas divisum** by showing the separate dorsal and ventral ducts.
- This imaging modality can clearly delineate the **anatomic variations**, including the anomalous drainage of the main pancreatic duct through the minor papilla.
- MRCP is considered the **gold standard non-invasive imaging** for pancreas divisum, superior to CT or transabdominal ultrasound.
*Endoscopic ultrasonography reveals a 'stack sign' in patients with this condition*
- The "stack sign" is typically associated with **autoimmune pancreatitis**, characterized by a homogenous, hypoechoic enlargement of the pancreas, and is not a feature of congenital anomalies like pancreas divisum.
- While EUS can visualize pancreatic ducts, it does not reveal a specific "stack sign" for pancreas divisum; the diagnosis relies on demonstrating separate ducts draining into different papillae.
*Patients with recurrent episodes of pancreatitis due to this condition do not require any intervention*
- Patients with **symptomatic pancreas divisum**, especially those with recurrent **pancreatitis**, often benefit from intervention such as **endoscopic sphincterotomy** of the minor papilla to improve drainage.
- Leaving symptomatic cases untreated can lead to continued episodes of pancreatitis, causing progressive pancreatic damage and complications.
*It is the most common congenital anomaly of the pancreas*
- This statement is **factually true** - pancreas divisum affects 5-10% of the population and is indeed the most common congenital pancreatic anomaly.
- However, in the context of this question asking what "**best describes** this anomaly," the statement about MRCP is more directly relevant as it describes the **diagnostic characteristics** rather than just epidemiological prevalence.
- While this is an important fact about pancreas divisum, it is less specific in describing the anomaly itself compared to the diagnostic imaging features.
*Most of the patients with this condition present in early childhood with abdominal symptoms*
- The majority of individuals with **pancreas divisum** are **asymptomatic** throughout their lives (up to 95% remain asymptomatic).
- When symptoms do occur, they typically manifest in **adulthood**, often as recurrent episodes of acute pancreatitis due to impaired drainage through the minor papilla.
Question 10: A 24-year-old female presents to her primary care physician with right knee pain for the last week. She states that she first noticed it after a long flight on her way back to the United States from Russia, where she had run a marathon along a mountain trail. The patient describes the pain as dull, aching, and localized to the front of her kneecap, and it worsens with sitting but improves with standing. Aspirin has not provided significant relief. The patient has a history of a torn anterior cruciate ligament (ACL) on the right side from a soccer injury three years ago. In addition, she was treated for gonorrhea last month after having intercourse with a new partner. At this visit, the patient’s temperature is 98.5°F (36.9°C), blood pressure is 112/63 mmHg, pulse is 75/min, and respirations are 14/min. Which of the following is most likely to establish the diagnosis?
A. Ballotable patella test
B. MRI of the knee
C. Anterior drawer test
D. Patellar compression with extended knee (Correct Answer)
E. Plain radiograph of the knee
Explanation: ***Patellar compression with extended knee***
- This maneuver helps to diagnose **patellofemoral pain syndrome** by compressing the patella against the femur, exacerbating symptoms if the articular cartilage is irritated. The patient's symptoms of **anterior knee pain** worsening with sitting and improving with standing, especially after intense physical activity (marathon) and a flight, are highly suggestive of patellofemoral pain syndrome ("runner's knee" or "airplane knee").
- The patient's history of a prior **ACL tear** may predispose her to patellofemoral pain due to altered knee biomechanics and muscle imbalances.
*Ballotable patella test*
- This test is used to detect significant **knee effusion**, but the patient's symptoms are not indicative of a large effusion, and this test would not specifically diagnose patellofemoral pain syndrome.
- While some joint swelling can occur with patellofemoral pain, a ballotable patella suggests a more substantial fluid accumulation, which is not the primary symptom here.
*MRI of the knee*
- An MRI might show cartilage changes or other structural abnormalities but is generally not the initial diagnostic test for **patellofemoral pain syndrome**, which is primarily a clinical diagnosis.
- Furthermore, MRI is an expensive imaging modality and is usually reserved for cases where other diagnoses are suspected or if conservative treatment fails.
*Anterior drawer test*
- This test assesses the integrity of the **anterior cruciate ligament (ACL)**. While the patient has a history of an ACL tear, her current symptoms are not consistent with acute ACL instability, but rather chronic anterior knee pain.
- The anterior drawer test would be positive if there was an ongoing ACL tear or laxity, but it would not specifically diagnose patellofemoral pain syndrome.
*Plain radiograph of the knee*
- Plain radiographs are useful for identifying **bony abnormalities** like fractures, osteophytes, or severe arthritis, but they are typically normal in cases of patellofemoral pain syndrome.
- They would not show the inflammation or cartilage irritation characteristic of patellofemoral pain, although they might rule out other bone-related causes of pain.
