Anatomical approach to differential diagnosis US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Anatomical approach to differential diagnosis. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Anatomical approach to differential diagnosis US Medical PG Question 1: A 12-year-old boy is brought to the emergency department late at night by his worried mother. She says he has not been feeling well since this morning after breakfast. He skipped both lunch and dinner. He complains of abdominal pain as he points towards his lower abdomen but says that the pain initially started at the center of his belly. His mother adds that he vomited once on the way to the hospital. His past medical history is noncontributory and his vaccinations are up to date. His temperature is 38.1°C (100.6°F), pulse is 98/min, respirations are 20/min, and blood pressure is 110/75 mm Hg. Physical examination reveals right lower quadrant tenderness. The patient is prepared for laparoscopic abdominal surgery. Which of the following structures is most likely to aid the surgeons in finding the source of this patient's pain and fever?
- A. McBurney's point
- B. Linea Semilunaris
- C. Transumbilical plane
- D. Arcuate line
- E. Teniae coli (Correct Answer)
Anatomical approach to differential diagnosis Explanation: ***Teniae coli***
- The **teniae coli** are three distinct longitudinal bands of smooth muscle that run along the length of the large intestine, converging at the base of the appendix. They serve as reliable anatomical landmarks for locating the appendix during surgery.
- Given the patient's symptoms (periumbilical pain migrating to the right lower quadrant, fever, vomiting, and right lower quadrant tenderness), **acute appendicitis** is highly suspected, making the teniae coli crucial for surgical identification of the inflamed appendix.
*McBurney's point*
- **McBurney's point** is a clinical landmark on the abdominal wall, two-thirds of the way from the umbilicus to the right anterior superior iliac spine, that often corresponds to the base of the appendix. It is used to elicit tenderness during physical examination.
- While tenderness at McBurney's point is a strong indicator of appendicitis, it is a **surface landmark** for diagnosis and not an internal anatomical structure that aids the surgeon in _finding_ the appendix during a laparoscopic procedure.
*Linea Semilunaris*
- The **linea semilunaris** is the curved tendinous intersection found at the lateral border of the rectus abdominis muscle, extending from the costal margin to the pubic tubercle.
- It defines the lateral extent of the rectus sheath but has **no direct anatomical relationship** to the appendix or its surgical identification.
*Transumbilical plane*
- The **transumbilical plane** is an imaginary horizontal plane passing through the umbilicus. It is used in topographical anatomy for abdominal segmentation.
- It is a **surface and arbitrary anatomical plane** for regional description, not an internal structure that guides surgical access to or identification of the appendix.
*Arcuate line*
- The **arcuate line** is a crescent-shaped anatomical landmark located on the posterior wall of the rectus sheath, inferior to the umbilicus, marking the transition where the aponeuroses of the transverse abdominis and internal oblique muscles pass anterior to the rectus abdominis.
- This line is relevant to the integrity of the rectus sheath but is **anatomically distant from the appendix** and does not assist in its surgical localization.
Anatomical approach to differential diagnosis US Medical PG Question 2: A 54-year-old man comes to the physician for the evaluation of difficulty swallowing of both solids and liquids for 1 month. During the past 5 months, he has also had increased weakness of his hands and legs. He sails regularly and is unable to hold the ropes as tightly as before. Ten years ago, he was involved in a motor vehicle collision. Examination shows atrophy of the tongue. Muscle strength is decreased in the right upper and lower extremities. There is muscle stiffness in the left lower extremity. Deep tendon reflexes are 1+ in the right upper and lower extremities, 3+ in the left upper extremity, and 4+ in the left lower extremity. Plantar reflex shows an extensor response on the left foot. Sensation to light touch, pinprick, and vibration is intact. Which of the following is the most likely diagnosis?
- A. Amyotrophic lateral sclerosis (Correct Answer)
- B. Inclusion-body myositis
- C. Subacute combined degeneration of spinal cord
- D. Syringomyelia
- E. Cervical spondylosis with myelopathy
Anatomical approach to differential diagnosis Explanation: ***Amyotrophic lateral sclerosis***
- This diagnosis accounts for the combination of **upper motor neuron** (spasticity, hyperreflexia, extensor plantar response) and **lower motor neuron** (weakness, atrophy, dysphagia, tongue atrophy) signs and symptoms.
- The progressive weakness in both hands and legs, alongside **dysphagia** (difficulty swallowing) and **dysarthria** (implied by tongue atrophy), is highly characteristic of ALS, a neurodegenerative disorder affecting motor neurons.
*Cervical spondylosis with myelopathy*
- While it can cause some **upper motor neuron signs** (spasticity, hyperreflexia), it does not typically present with prominent **lower motor neuron signs** like widespread muscle atrophy or tongue atrophy.
- Sensation is usually impaired below the level of compression, but in this patient, sensation is **intact**, making cervical myelopathy less likely.
*Inclusion-body myositis*
- This is a **muscle disease** causing progressive weakness and atrophy, particularly in the quadriceps and forearm flexors, often with **dysphagia**.
- However, it is primarily a **myopathy** and does not cause **upper motor neuron signs** such as spasticity, hyperreflexia, or an extensor plantar response.
*Subacute combined degeneration of spinal cord*
- This condition is caused by **vitamin B12 deficiency** and typically presents with a combination of **sensory ataxia**, weakness, and **paresthesias**, affecting the dorsal and lateral columns.
- It usually presents with **paresthesias** and **sensory deficits** (especially vibratory sense and proprioception), which are specifically noted as intact in this patient.
*Syringomyelia*
- This involves a **fluid-filled cyst (syrinx)** within the spinal cord, leading to a classic "cape-like" distribution of **loss of pain and temperature sensation** in the upper extremities due to damage to the spinothalamic tracts.
- While it can cause weakness and atrophy, it characteristically spares light touch, vibration, and position sense but involves **dissociated sensory loss**, which is not seen in this patient.
Anatomical approach to differential diagnosis US Medical PG Question 3: A 74-year-old woman is brought by ambulance to the emergency department and presents with a complaint of excruciating chest pain that started about 45 minutes ago. The patient was sitting in the garden when she 1st noticed the pain in the upper abdomen. The pain has persisted and now localizes underneath of the sternum and the left shoulder. Milk of magnesia and aspirin were tried with no relief. The patient had previous episodes of chest pain that were of lesser intensity and rarely lasted more than 10 minutes. She is diabetic and has been managed for hypertension and rheumatoid arthritis in the past. On examination, the patient is breathless and sweating profusely. The vital signs include blood pressure 140/90 mm Hg and heart rate 118/min. The electrocardiogram (ECG) shows Q waves in leads V2 and V3 and raised ST segments in leads V2, V3, V4, and V5. Laboratory studies (including cardiac enzymes at 6 hours after admission show:
Hematocrit 45%
Troponin T 1.5 ng/mL
Troponin I 0.28 ng/mL
Creatine kinase (CK)-MB 0.25 ng/mL
The patient is admitted and started on analgesia and reperfusion therapy. She shows initial signs of recovery until the 6th day of hospitalization when she starts vomiting and complaining of dizziness. Physical examination findings at this time included heart rate 110/min, temperature 37.7°C (99.9°F), blood pressure 90/60 mm Hg. Jugular venous pressure is 8 cm. A harsh pansystolic murmur is present at the left lower sternal border. ECG shows sinus tachycardia and ST-segment elevation with terminal negative T waves. Laboratory studies show:
Hematocrit 38%
Troponin T 1.15ng/mL
Troponin I 0.18 ng/mL
CK-MB 0.10 ng/mL
Which of the following best explains the patient's current clinical condition?
- A. Aortic dissection complicating myocardial infarction
- B. A new myocardial infarction (re-infarction)
- C. Acute ventricular septal rupture complicating myocardial infarction (Correct Answer)
- D. Acute pericarditis complicating myocardial infarction
- E. Cardiac tamponade complicating myocardial infarction
Anatomical approach to differential diagnosis Explanation: ***Acute ventricular septal rupture complicating myocardial infarction***
- The development of a **harsh pansystolic murmur** at the **left lower sternal border** along with signs of **heart failure** (hypotension, tachycardia, increased JVP) approximately a week after a large anterior MI is highly suggestive of **ventricular septal rupture (VSR)**.
- The continued ECG changes (ST elevation with terminal negative T waves) and elevated, though improving, cardiac enzymes are consistent with the ongoing myocardial injury and the complications related to it.
*Aortic dissection complicating myocardial infarction*
- **Aortic dissection** typically presents with **sudden, severe, tearing chest pain** radiating to the back, which is distinct from the patient's initial presentation.
- While it can cause hemodynamic instability, it does not typically produce a **pansystolic murmur** at the left lower sternal border.
*A new myocardial infarction (re-infarction)*
- While the patient is still experiencing symptoms and some ECG changes, the **prominent new pansystolic murmur** and signs of acute heart failure are more indicative of a **mechanical complication** than simply a new MI.
- The cardiac enzyme levels, though still elevated, are trending downwards, which would be inconsistent with a large new infarction.
*Acute pericarditis complicating myocardial infarction*
- **Acute pericarditis** would typically present with **pleuritic chest pain** that improves when leaning forward and a characteristic **pericardial friction rub**.
- It would not explain the **pansystolic murmur** or the sudden hemodynamic deterioration to the same extent as VSR.
*Cardiac tamponade complicating myocardial infarction*
- **Cardiac tamponade** is characterized by **Beck's triad** (hypotension, JVD, muffled heart sounds) and pulsus paradoxus. While the patient has hypotension and JVD, the presence of a **harsh pansystolic murmur** points away from tamponade and towards a structural defect.
Anatomical approach to differential diagnosis US Medical PG Question 4: A 24-year-old woman comes to the emergency department because of abdominal pain, fever, nausea, and vomiting for 12 hours. Her abdominal pain was initially dull and diffuse but has progressed to a sharp pain on the lower right side. Two years ago she had to undergo right salpingo-oophorectomy after an ectopic pregnancy. Her temperature is 38.7°C (101.7°F). Physical examination shows severe right lower quadrant tenderness with rebound tenderness; bowel sounds are decreased. Laboratory studies show leukocytosis with left shift. An abdominal CT scan shows a distended, edematous appendix. The patient is taken to the operating room for an appendectomy. During the surgery, the adhesions from the patient's previous surgery make it difficult for the resident physician to identify the appendix. Her attending mentions that she should use a certain structure for guidance to locate the appendix. The attending is most likely referring to which of the following structures?
- A. Epiploic appendages
- B. Right ureter
- C. Deep inguinal ring
- D. Ileocolic artery
- E. Teniae coli (Correct Answer)
Anatomical approach to differential diagnosis Explanation: ***Teniae coli***
- The **teniae coli** are three distinct longitudinal bands of smooth muscle that run along the length of the cecum and colon, converging at the base of the **appendix**.
- Following these bands inferiorly from the ascending colon or cecum during surgery is a reliable method to locate the **vermiform appendix**, especially in the presence of adhesions.
*Epiploic appendages*
- These are small, fat-filled sacs that protrude from the surface of the **large intestine** but are not directly used as a reliable landmark for locating the appendix.
- While present in the vicinity, they do not consistently lead to the base of the appendix like the teniae coli.
*Right ureter*
- The **right ureter** is located retroperitoneally, deep to the cecum and appendix, and is not a direct anatomical landmark used for identifying the appendix during an appendectomy.
- Identifying the ureter is important to avoid injury, but not for localizing the appendix.
*Deep inguinal ring*
- The **deep inguinal ring** is an opening in the transversalis fascia, involved in the formation of the inguinal canal, and is located far anterior and inferior to the region of the appendix.
- It has no anatomical relationship that would guide a surgeon to locate the appendix.
*Ileocolic artery*
- The **ileocolic artery** branches from the superior mesenteric artery and supplies the terminal ileum, cecum, and appendix. While it provides blood supply to the appendix, it is not a direct or consistent surface landmark for locating the appendix itself, especially in complex cases with adhesions.
- Locating the artery would be more complex and less reliable for initial identification compared to the teniae coli.
Anatomical approach to differential diagnosis US Medical PG Question 5: A 48-year-old woman presents to the emergency department because of increasingly severe right upper abdominal pain, fever, and non-bloody vomiting for the last 5 hours. The pain is dull, intermittent, and radiates to her right shoulder. During the past 3 months, she has had recurring abdominal discomfort after meals. The patient underwent an appendectomy more than 30 years ago. She has hypertension, diabetes mellitus type 2, and chronic back pain. She takes bisoprolol, metformin, and ibuprofen daily. She is 171 cm (5 ft 6 in) tall and weighs 99 kg (218 lb). Her BMI is 35.2 kg/m2. She appears uncomfortable and is clutching her abdomen. Her temperature is 38.5°C (101.3°F), pulse is 108/min, and blood pressure is 150/82 mm Hg. Abdominal examination shows right upper quadrant abdominal tenderness and guarding. Upon deep palpation of the right upper quadrant, the patient pauses during inspiration. Laboratory studies show the following:
Blood
Hemoglobin 13.1 g/dL
Leukocyte count 10,900/mm3
Platelet count 236,000/mm3
Mean corpuscular volume 89/µm3
Serum
Urea nitrogen 28 mg/dL
Glucose 89 mg/dL
Creatinine 0.7 mg/dL
Bilirubin
Total 1.6 mg/dL
Direct 1.1 mg/dL
Alkaline phosphatase 79 U/L
Alanine aminotransferase (ALT, GPT) 28 U/L
Aspartate aminotransferase (AST, GOT) 32 U/L
An X-ray of the abdomen shows no abnormalities. Further evaluation of the patient is most likely to reveal which of the following?
- A. History of recent travel to Indonesia
- B. Frequent, high-pitched bowel sounds on auscultation
- C. History of multiple past pregnancies (Correct Answer)
- D. Elevated carbohydrate-deficient transferrin
- E. History of recurrent sexually transmitted infections
Anatomical approach to differential diagnosis Explanation: ***History of multiple past pregnancies***
- This patient's symptoms (right upper quadrant pain radiating to the shoulder, guarding, positive Murphy's sign on deep palpation) along with fever and leukocytosis are highly suggestive of **acute cholecystitis**, likely due to gallstones.
- The "5 F's" risk factors for gallstones include **fat, female, forty, fertile (multiple pregnancies), and fair**, making a history of multiple pregnancies a highly relevant finding in this clinical context.
*History of recent travel to Indonesia*
- Recent travel to certain regions, including Indonesia, might increase the risk of certain **infectious diarrheal diseases** or **parasitic infections** that could cause abdominal pain.
- However, the classic symptoms and signs presented in the patient (RUQ pain, radiation to shoulder, positive Murphy's, fever, leukocytosis) are not typical for travel-related infections and point more strongly to biliary pathology.
*Frequent, high-pitched bowel sounds on auscultation*
- **High-pitched bowel sounds** are often associated with **bowel obstruction**, indicating hyperperistalsis above the obstruction point trying to push contents forward.
- This patient's presentation is consistent with acute cholecystitis, not bowel obstruction, and her abdominal X-ray was normal, making bowel obstruction less likely.
*Elevated carbohydrate-deficient transferrin*
- **Carbohydrate-deficient transferrin (CDT)** is a biomarker primarily used to detect **chronic excessive alcohol consumption**.
- While chronic alcohol use can contribute to various gastrointestinal issues (e.g., pancreatitis, liver disease), this patient's presentation is not typical of alcohol-related illness, and elevated CDT would not directly explain her acute cholecystitis symptoms.
*History of recurrent sexually transmitted infections*
- A history of recurrent sexually transmitted infections (STIs) might be relevant for conditions like **pelvic inflammatory disease (PID)**, which can sometimes cause right upper quadrant pain if it leads to **Fitz-Hugh-Curtis syndrome** (perihepatitis).
- However, the patient's presentation with classic signs of cholecystitis (Murphy's sign, radiation to shoulder, risk factors) along with elevated total and direct bilirubin, is much more indicative of biliary disease than an STI-related complication.
Anatomical approach to differential diagnosis US Medical PG Question 6: A 72-year-old woman is brought in to the emergency department after her husband noticed that she appeared to be choking on her dinner. He performed a Heimlich maneuver but was concerned that she may have aspirated something. The patient reports a lack of pain and temperature on the right half of her face, as well as the same lack of sensation on the left side of her body. She also states that she has been feeling "unsteady" on her feet. On physical exam you note a slight ptosis on the right side. She is sent for an emergent head CT. Where is the most likely location of the neurological lesion?
- A. Pons
- B. Internal capsule
- C. Cervical spinal cord
- D. Medulla (Correct Answer)
- E. Midbrain
Anatomical approach to differential diagnosis Explanation: ***Medulla***
- This presentation describes **Wallenberg syndrome** (lateral medullary syndrome), characterized by **ipsilateral facial sensory loss**, **contralateral body sensory loss**, and **ataxia** due to involvement of the spinothalamic tracts, trigeminal nucleus, and cerebellar pathways.
- **Dysphagia** (choking) and **Horner's syndrome** (ptosis, miosis, anhidrosis) are also classic signs, specifically the ptosis seen here, pointing to an infarct in the **lateral medulla**.
*Pons*
- Lesions in the pons typically present with varying degrees of **cranial nerve deficits** (e.g., trigeminal, abducens, facial) and **motor or sensory deficits** affecting both sides of the body due to the decussation of tracts.
- The specific combination of **crossed sensory loss** and other symptoms seen here is not characteristic of isolated pontine lesions.
*Internal capsule*
- A lesion in the internal capsule would primarily cause **contralateral motor weakness (hemiparesis)** and **sensory loss** affecting both the face and body on the same side, without the ipsilateral facial involvement.
- It would not explain the **ataxia** or specific cranial nerve signs like ptosis.
*Cervical spinal cord*
- Spinal cord lesions result in **sensory and motor deficits below the level of the lesion**, affecting both sides of the body symmetrically, or ipsilaterally depending on the tract involved.
- They do not cause **facial sensory disturbances**, **dysphagia**, or **ataxia** in the manner described.
*Midbrain*
- Midbrain lesions typically involve the **oculomotor nerve** (CN III), causing eye movement abnormalities, and can result in **contralateral hemiparesis**.
- They do not produce the **crossed sensory deficits** (ipsilateral face, contralateral body) or **ataxia** characteristic of this case.
Anatomical approach to differential diagnosis US Medical PG Question 7: A 65-year-old man presents to the emergency department for sudden weakness. He was doing mechanical work on his car where he acutely developed right-leg weakness and fell to the ground. He is accompanied by his wife, who said that this has never happened before. He was last seen neurologically normal approximately 2 hours prior to presentation. His past medical history is significant for hypertension and type II diabetes. His temperature is 98.8°F (37.1°C), blood pressure is 177/108 mmHg, pulse is 90/min, respirations are 15/min, and oxygen saturation is 99% on room air. Neurological exam reveals that he is having trouble speaking and has profound weakness of his right upper and lower extremity. Which of the following is the best next step in management?
- A. Thrombolytics
- B. Noncontrast head CT (Correct Answer)
- C. CT angiogram
- D. MRI of the head
- E. Aspirin
Anatomical approach to differential diagnosis Explanation: ***Noncontrast head CT***
- A **noncontrast head CT** is the most crucial initial step in managing acute stroke symptoms because it can rapidly rule out an **intracranial hemorrhage**.
- Distinguishing between ischemic stroke and hemorrhagic stroke is critical, as the management strategies are vastly different and administering thrombolytics in the presence of hemorrhage can be fatal.
*Thrombolytics*
- **Thrombolytics** can only be administered after an **intracranial hemorrhage** has been excluded via noncontrast head CT.
- Administering thrombolytics without imaging could worsen a hemorrhagic stroke, causing significant harm or death.
*CT angiogram*
- A **CT angiogram** is used to identify large vessel occlusions in ischemic stroke and is typically performed after a noncontrast CT rules out hemorrhage.
- This imaging is crucial for determining eligibility for **endovascular thrombectomy** but is not the very first diagnostic step.
*MRI of the head*
- An **MRI of the head** is more sensitive for detecting acute ischemic changes but takes longer to perform and is often not readily available in the acute emergency setting.
- It is not the initial imaging of choice for ruling out hemorrhage due to its longer acquisition time compared to CT.
*Aspirin*
- **Aspirin** is indicated for acute ischemic stroke but should only be given after an **intracranial hemorrhage** has been ruled out.
- Like thrombolytics, aspirin could exacerbate a hemorrhagic stroke and is thus deferred until initial imaging is complete.
Anatomical approach to differential diagnosis US Medical PG Question 8: A 55-year-old woman presents to the emergency department with retrosternal pain that started this evening. The patient states that her symptoms started as she was going to bed after taking her medications. She describes the pain as sudden in onset, worse with swallowing, and not associated with exertion. The patient has a past medical history of diabetes, anemia, and congestive heart failure and is currently taking metoprolol, insulin, metformin, iron, and lisinopril. Her temperature is 99.2°F (37.3°C), blood pressure is 125/63 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 100% on room air. Physical exam is notable for an obese woman who appears uncomfortable. An initial electrocardiogram (ECG) demonstrates sinus rhythm, and a set of troponins are pending. Which of the following is the most likely diagnosis?
- A. Spontaneous pneumothorax
- B. Myocardial infarction
- C. Esophageal rupture
- D. Pulmonary embolism
- E. Esophagitis (Correct Answer)
Anatomical approach to differential diagnosis Explanation: ***Esophagitis***
- The patient's presentation with **sudden onset retrosternal pain** that is **worse with swallowing** (odynophagia) shortly after taking medications and going to bed strongly suggests **pill-induced esophagitis**.
- Medications, especially those that are acidic or poorly dissolved like iron supplements (which the patient is taking), can cause direct mucosal injury if they remain in contact with the esophageal lining for too long.
*Spontaneous pneumothorax*
- This typically presents with **sudden onset pleuritic chest pain** and **shortness of breath**, often accompanied by ipsilateral diminished breath sounds.
- The patient's pain is described as worse with swallowing, not breathing, and there is no mention of respiratory distress or physical exam findings consistent with a pneumothorax.
*Myocardial infarction*
- While retrosternal pain is a hallmark, MI pain is typically described as **pressure-like** or **squeezing**, often **radiating** to the arm, neck, or jaw, and is usually **exertion-related**.
- The patient's pain is sudden, worse with swallowing, and specifically *not* associated with exertion, and her ECG is currently stable.
*Esophageal rupture*
- This is a catastrophic event usually presenting with **severe, acute, excruciating chest pain**, often following forceful vomiting, retching, or iatrogenic injury.
- While it causes odynophagia and retrosternal pain, the patient's symptoms are less severe, and there are no signs of mediastinitis or sepsis typically seen with rupture.
*Pulmonary embolism*
- A PE usually presents with **sudden onset dyspnea**, **pleuritic chest pain**, and sometimes **hemoptysis**.
- The patient's pain is primarily linked to swallowing and not described as pleuritic, and her oxygen saturation is 100% on room air, making PE less likely.
Anatomical approach to differential diagnosis US Medical PG Question 9: A previously healthy 33-year-old woman comes to the physician because of pain and sometimes numbness in her right thigh for the past 2 months. She reports that her symptoms are worse when walking or standing and are better while sitting. Three months ago, she started going to a fitness class a couple times a week. She is 163 cm (5 ft 4 in) tall and weighs 88 kg (194 lb); BMI is 33.1 kg/m2. Her vital signs are within normal limits. Examination of the skin shows no abnormalities. Sensation to light touch is decreased over the lateral aspect of the right anterior thigh. Muscle strength is normal. Tapping the right inguinal ligament leads to increased numbness of the affected thigh. The straight leg test is negative. Which of the following is the most appropriate next step in management of this patient?
- A. Advise patient to wear looser pants (Correct Answer)
- B. Reduction of physical activity
- C. MRI of the lumbar spine
- D. X-ray of the hip
- E. Blood work for inflammatory markers
Anatomical approach to differential diagnosis Explanation: ***Advise patient to wear looser pants***
- This patient presents with symptoms consistent with **meralgia paresthetica**, a condition caused by compression of the **lateral femoral cutaneous nerve (LFCN)**. Modifying clothing or belts that compress the inguinal ligament can relieve pressure on the nerve.
- Her increased weight, a recent increase in physical activity, and a positive Tinel's sign at the inguinal ligament (tapping leads to increased numbness) support this diagnosis.
*Reduction of physical activity*
- While excessive physical activity can contribute to meralgia paresthetica, simply reducing it without addressing the underlying compression might not fully resolve symptoms.
- The patient has recently increased physical activity, which could be a contributing factor, but it's not the primary or most direct intervention for nerve compression.
*MRI of the lumbar spine*
- An MRI of the lumbar spine would be considered if there were signs of **radiculopathy** or other spinal pathology, such as weakness, reflex changes, or a positive straight leg test, which are absent here.
- The symptoms are localized to the distribution of the LFCN, and the physical exam points away from a central spinal cause.
*X-ray of the hip*
- An X-ray of the hip would be indicated for suspected **hip joint pathology** or **bony abnormalities**, which are not suggested by the patient's symptoms (pain and numbness in the thigh, not hip joint pain).
- Meralgia paresthetica is a nerve entrapment syndrome, not a structural issue of the hip joint.
*Blood work for inflammatory markers*
- Inflammatory markers like **ESR** or **CRP** would be relevant if an **inflammatory arthritis**, infection, or systemic inflammatory condition was suspected, but the patient's symptoms are purely neurological and localized.
- There is no clinical evidence of inflammation, fever, or joint swelling to suggest an underlying inflammatory process.
Anatomical approach to differential diagnosis US Medical PG Question 10: A 43-year-old woman presents to the neurology clinic in significant pain. She reports a sharp, stabbing electric-like pain on the right side of her face. The pain started suddenly 2 weeks ago. The pain is so excruciating that she can no longer laugh, speak, or eat her meals as these activities cause episodes of pain. She had to miss work last week as a result. Her attacks last about 3 minutes and go away when she goes to sleep. She typically has 2–3 attacks per day now. The vital signs include: blood pressure 132/84 mm Hg, heart rate 79/min, and respiratory rate 14/min. A neurological examination shows no loss of crude touch, tactile touch, or pain sensations on the right side of the face. The pupillary light and accommodation reflexes are normal. There is no drooping of her mouth, ptosis, or anhidrosis noted. Which of the following is the most likely diagnosis?
- A. Atypical facial pain
- B. Cluster headache
- C. Trigeminal neuralgia (Correct Answer)
- D. Bell’s palsy
- E. Basilar migraine
Anatomical approach to differential diagnosis Explanation: ***Trigeminal neuralgia***
- The patient's presentation of sudden, sharp, stabbing, electric-shock-like pain on one side of the face, triggered by activities like speaking, eating, and laughing, is highly characteristic of **trigeminal neuralgia**.
- The attacks are typically brief (lasting seconds to minutes), severe, and can cause significant functional impairment, consistent with the patient's report of missed work and inability to eat or speak.
*Atypical facial pain*
- This condition involves persistent, aching, or burning facial pain without clear neurological deficits, and it often does not have the paroxysmal, electric-shock quality seen in trigeminal neuralgia.
- Unlike **trigeminal neuralgia**, atypical facial pain is usually continuous rather than episodic and is not typically triggered by specific activities.
*Cluster headache*
- Characterized by severe, unilateral pain, often periorbital or temporal, accompanied by autonomic symptoms such as **lacrimation, conjunctival injection, nasal congestion, rhinorrhea, sweating, miosis, ptosis, and eyelid edema**.
- While very painful, the pain quality is usually deep and boring, not typically described as sharp, electric-shock like, and it is not triggered by facial movements like eating or speaking.
*Bell’s palsy*
- This condition involves **acute unilateral facial weakness or paralysis** due to inflammation of the facial nerve (CN VII), not pain as the primary symptom.
- While some patients may experience mild pain around the ear, the hallmark is facial muscle weakness leading to drooping of the mouth and inability to close the eye, which are absent in this patient.
*Basilar migraine*
- A rare type of migraine with aura symptoms originating from the brainstem, including **vertigo, dysarthria, tinnitus, bilateral visual symptoms, ataxia, and sometimes decreased level of consciousness**.
- While it can cause severe headache, it does not typically present with the described electric-shock-like facial pain triggered by movement, and the neurological examination did not reveal brainstem symptoms.
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