Thoracic duct and right lymphatic duct US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Thoracic duct and right lymphatic duct. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Thoracic duct and right lymphatic duct US Medical PG Question 1: A 39-year-old man presents with painless swelling of the right testis and a sensation of heaviness. The physical examination revealed an intra-testicular solid mass that could not be felt separately from the testis. After a thorough evaluation, he was diagnosed with testicular seminoma. Which of the following group of lymph nodes are most likely involved?
- A. Superficial inguinal lymph nodes (lateral group)
- B. Deep inguinal lymph nodes
- C. Superficial inguinal lymph nodes (medial group)
- D. Para-rectal lymph nodes
- E. Para-aortic lymph nodes (Correct Answer)
Thoracic duct and right lymphatic duct Explanation: ***Para-aortic lymph nodes***
- The **testes** develop in the abdomen and descend into the scrotum, retaining their original lymphatic drainage. Therefore, **testicular cancer** typically metastasizes to the **para-aortic** (or retroperitoneal) lymph nodes, which are located near the renal veins at the level of L1-L2.
- This is the primary lymphatic drainage pathway for the testes.
*Superficial inguinal lymph nodes (lateral group)*
- These lymph nodes primarily drain the skin of the **scrotum**, perineum, and lower limbs, but not the **testes** themselves.
- Involvement would suggest spread to the scrotal skin or compromised lymphatic flow due to prior scrotal surgery or infection, which is not indicated here.
*Deep inguinal lymph nodes*
- **Deep inguinal lymph nodes** drain structures deeper in the leg and gluteal region, as well as receiving efferent vessels from the superficial inguinal nodes.
- They are not the primary drainage site for the **testes**.
*Superficial inguinal lymph nodes (medial group)*
- Similar to the lateral group, the **medial superficial inguinal lymph nodes** primarily drain the external genitalia (excluding the testes), perineum, and lower abdominal wall.
- They are not the direct drainage route for **testicular cancer**.
*Para-rectal lymph nodes*
- **Para-rectal lymph nodes** are located near the rectum and are involved in the drainage of the rectum and lower sigmoid colon.
- They have no direct connection to the lymphatic drainage of the **testes**.
Thoracic duct and right lymphatic duct US Medical PG Question 2: A 61-year-old man comes to the physician because of a 3-month history of worsening exertional dyspnea and a persistent dry cough. For 37 years he has worked in a naval shipyard. He has smoked 1 pack of cigarettes daily for the past 40 years. Pulmonary examination shows fine bibasilar end-expiratory crackles. An x-ray of the chest shows diffuse bilateral infiltrates predominantly in the lower lobes and pleural reticulonodular opacities. A CT scan of the chest shows pleural plaques and subpleural linear opacities. The patient is most likely to develop which of the following conditions?
- A. Malignant mesothelioma
- B. Spontaneous pneumothorax
- C. Bronchogenic carcinoma (Correct Answer)
- D. Aspergilloma
- E. Mycobacterial infection
Thoracic duct and right lymphatic duct Explanation: ***Bronchogenic carcinoma***
- This patient has **asbestosis** from 37 years of shipyard work (asbestos exposure) combined with a **40-pack-year smoking history**, creating a **synergistic risk** for lung cancer.
- Asbestos exposure alone increases lung cancer risk **5-fold**, smoking alone increases it **10-fold**, but **combined exposure increases the risk 50-fold** due to synergistic effects.
- The chest imaging findings (diffuse bilateral infiltrates, pleural reticulonodular opacities, pleural plaques, and subpleural linear opacities) confirm **asbestosis**, making **bronchogenic carcinoma** the most likely future complication.
*Malignant mesothelioma*
- While strongly associated with **asbestos exposure**, it is **not synergistic with smoking** and has a lower absolute incidence compared to bronchogenic carcinoma in patients with combined exposures.
- Mesothelioma typically presents with **unilateral pleural thickening**, pleural effusion, and chest pain rather than the diffuse parenchymal infiltrates and bibasilar crackles seen here.
*Spontaneous pneumothorax*
- Characterized by sudden lung collapse with acute chest pain and dyspnea, appearing on imaging as air in the pleural space.
- While smoking-related emphysema can lead to bullae rupture and pneumothorax, the primary findings here indicate chronic interstitial lung disease and pleural pathology from asbestos exposure.
*Mycobacterial infection*
- Would typically present with constitutional symptoms (fever, night sweats, weight loss) and possibly hemoptysis, which are not mentioned in this case.
- Imaging usually shows cavitary lesions, nodules, or upper lobe predominance, differing from the diffuse lower lobe infiltrates and pleural plaques characteristic of asbestosis.
*Aspergilloma*
- A fungal ball within a pre-existing cavity, typically seen in patients with tuberculosis, sarcoidosis, or other chronic cavitary lung diseases.
- The clinical presentation and imaging findings, particularly the occupational asbestos exposure and smoking history, point toward malignancy risk rather than fungal colonization.
Thoracic duct and right lymphatic duct US Medical PG Question 3: A 33-year-old woman is brought to the emergency department 15 minutes after being stabbed in the chest with a screwdriver. Her pulse is 110/min, respirations are 22/min, and blood pressure is 90/65 mm Hg. Examination shows a 5-cm deep stab wound at the upper border of the 8th rib in the left midaxillary line. Which of the following structures is most likely to be injured in this patient?
- A. Left kidney
- B. Left ventricle
- C. Intercostal nerve
- D. Lower lung lobe (Correct Answer)
- E. Spleen
Thoracic duct and right lymphatic duct Explanation: ***Lower lung lobe***
- A stab wound at the **8th rib in the left midaxillary line** is located within the anatomical boundaries of the **lower lobe of the left lung**. The diaphragm can rise to the level of the 5th intercostal space during expiration, and the lung extends into this region.
- The patient's **hypotension** and **tachycardia** are consistent with potential **hemorrhage** or **pneumothorax/hemothorax** due to lung injury.
*Left kidney*
- The left kidney is located retroperitoneally, typically at the level of the **T12 to L3 vertebrae**, making it less likely to be injured by a stab wound at the 8th rib in the midaxillary line of a standing or supine patient.
- Injury to the kidney would likely cause **hematuria**, which is not mentioned in the presentation as an immediate concern.
*Left ventricle*
- The left ventricle is located more medially and anteriorly within the chest, deep to the **sternum** and **costal cartilages**, making a stab wound at the 8th rib in the midaxillary line an unlikely entry point.
- Cardiac tamponade or severe hemorrhage from left ventricular injury would typically present with more rapid and profound hemodynamic collapse.
*Intercostal nerve*
- While an intercostal nerve would certainly be injured by a stab wound through the intercostal space, injury to the nerve alone would not explain the patient's **hemodynamic instability** (hypotension and tachycardia).
- Isolated intercostal nerve injury primarily causes **localized pain** and potentially some sensory or motor deficits in the distribution of that nerve.
*Spleen*
- The spleen is located in the left upper quadrant, typically lying beneath the **9th to 11th ribs**, making injury to the spleen possible with a deeper wound. However, it is situated more laterally and posteriorly than the lung at the 8th rib midaxillary line.
- While splenic injury can cause **hypotension** and **tachycardia**, the lung lies in a more superficial and posterior plane relative to the 8th rib in the midaxillary line, making it a more direct target for injury.
Thoracic duct and right lymphatic duct US Medical PG Question 4: A 76-year-old woman comes to the physician for evaluation of a 3-month history of vulvar itching and pain. She was diagnosed with lichen sclerosus 4 years ago. She has smoked 1 pack of cigarettes daily for 35 years. Physical examination shows a 2.5-cm nodular, ulcerative lesion on the vaginal introitus and left labia minora with surrounding erythema. Punch biopsy shows squamous cell carcinoma. A CT scan of the chest, abdomen, and pelvis shows enlarged lymph nodes concerning for metastatic disease. Which of the following lymph node regions is the most likely primary site of metastasis?
- A. Superficial inguinal (Correct Answer)
- B. Internal iliac
- C. External iliac
- D. Inferior mesenteric
- E. Para-aortic
Thoracic duct and right lymphatic duct Explanation: ***Superficial inguinal***
- The **vulva** drains primarily into the **superficial inguinal lymph nodes**, making them the most likely first site for metastatic spread from vulvar squamous cell carcinoma.
- The lesion's location on the **vaginal introitus** and **labia minora** directly correlates with this lymphatic drainage pathway.
*Internal iliac*
- **Internal iliac nodes** receive drainage mainly from deep pelvic structures like the cervix, upper vagina, and uterus, not directly from the vulva.
- Metastasis to these nodes usually occurs after involvement of more superficial nodes or in advanced disease with deeper invasion.
*External iliac*
- **External iliac nodes** generally drain the lower extremities and deeper pelvic structures (e.g., bladder, distal ureter), not the vulva as a primary site.
- Involvement here would typically indicate more advanced local spread or secondary metastasis from other pelvic nodes.
*Inferior mesenteric*
- **Inferior mesenteric nodes** drain the hindgut and its derivatives, including the distal colon and rectum, which are distant from the vulva.
- This region is not involved in the lymphatic drainage of the vulva.
*Para-aortic*
- **Para-aortic nodes** drain structures like the ovaries, fallopian tubes, and upper uterus; they are too superior for primary vulvar lymphatic drainage.
- Metastasis to these nodes from vulvar cancer would signify widespread, very advanced disease and not a primary site of spread.
Thoracic duct and right lymphatic duct US Medical PG Question 5: A 51-year-old woman comes to the physician because of swelling of her legs for 4 months. She first noticed the changes on the left leg, followed by the right leg. Sometimes her legs are itchy. She has a 1-month history of hoarseness. She returned from a trip to Mexico 8 months ago. She has a history of hypertension, constipation, and coronary artery disease. She works as a teacher at a primary school. Her mother had type-2 diabetes mellitus. She smoked one-half pack of cigarettes daily for 6 years but stopped smoking 11 years ago. She drinks one glass of wine daily and occasionally more on the weekend. Current medications include aspirin, bisoprolol, and atorvastatin. She is 165 cm (5 ft 5 in) tall and weighs 82 kg (181 lb); BMI is 30.1 kg/m2. Vital signs are within normal limits. Examination shows bilateral pretibial non-pitting edema. The skin is indurated, cool, and dry. Peripheral pulses are palpated bilaterally. The remainder of the examination shows no abnormalities. The patient is at increased risk for which of the following conditions?
- A. Cardiovascular complications
- B. Respiratory depression
- C. Hypothermia
- D. Cognitive impairment
- E. Myxedema coma (Correct Answer)
Thoracic duct and right lymphatic duct Explanation: ***Myxedema coma***
- The patient's symptoms of **non-pitting pretibial edema**, **hoarseness**, **cold and dry skin**, along with **constipation** and elevated BMI (30.1), are highly suggestive of **severe hypothyroidism**
- **Myxedema coma** is a life-threatening endocrine emergency representing the most severe manifestation of untreated hypothyroidism
- This patient with undiagnosed/untreated hypothyroidism is at highest risk for progression to myxedema coma, particularly if exposed to precipitating factors (infection, cold exposure, medications, surgery)
- Myxedema coma has high mortality (20-50%) and requires urgent recognition and treatment
*Cardiovascular complications*
- While hypothyroidism increases cardiovascular risk (bradycardia, pericardial effusion, heart failure), these are chronic complications
- The patient already has coronary artery disease, but the question asks about increased risk given the current presentation of severe hypothyroidism
- Myxedema coma represents a more immediate and life-threatening risk
*Respiratory depression*
- Respiratory depression can occur in severe hypothyroidism due to decreased respiratory drive and respiratory muscle weakness
- However, respiratory depression is typically a **feature of myxedema coma** rather than a separate entity
- Myxedema coma is the more comprehensive and critical diagnosis
*Hypothermia*
- Hypothermia is common in severe hypothyroidism due to decreased metabolic rate
- However, hypothermia is an **associated finding** of myxedema coma, not a separate complication
- Myxedema coma encompasses hypothermia along with altered mental status, cardiovascular collapse, and other systemic manifestations
*Cognitive impairment*
- Cognitive impairment (slowed thinking, memory problems, depression) can occur in chronic hypothyroidism
- This is a less acute and less life-threatening manifestation compared to the severe metabolic decompensation of myxedema coma
- Altered mental status in myxedema coma is more severe than chronic cognitive impairment
Thoracic duct and right lymphatic duct US Medical PG Question 6: A CT scan of the abdomen reveals a mass in the pancreatic uncinate process. Which of the following structures is most likely to be compressed by this mass?
- A. Common bile duct
- B. Portal vein
- C. Splenic vein
- D. Superior mesenteric vein (Correct Answer)
Thoracic duct and right lymphatic duct Explanation: ***Superior mesenteric vein***
- The **uncinate process** of the pancreas hooks around the **superior mesenteric vessels**. Therefore, a mass in this region would most directly compress the **superior mesenteric vein (SMV)** and artery (SMA).
- Compression of the SMV can lead to **venous outflow obstruction** from the small intestine, potentially causing **bowel ischemia** or edema.
*Common bile duct*
- The **common bile duct** passes through the **head of the pancreas**, not typically the uncinate process.
- Compression of the common bile duct would more commonly be associated with masses in the **head of the pancreas**, leading to **jaundice**.
*Portal vein*
- The **portal vein** is formed by the union of the **splenic vein** and the **superior mesenteric vein**, generally posterior to the neck of the pancreas.
- While pancreatic masses can affect the portal vein, a mass specifically in the uncinate process would more directly impinge on the SMV before significantly affecting the main portal vein, which is superior and posterior to the uncinate process.
*Splenic vein*
- The **splenic vein** runs along the **posterior aspect of the body and tail of the pancreas**.
- A mass in the uncinate process, located at the inferior margin of the head, is relatively distant from the splenic vein.
Thoracic duct and right lymphatic duct US Medical PG Question 7: An otherwise healthy 39-year-old woman presents to her primary care provider because of right-leg swelling, which started 4 months ago following travel to Kenya. The swelling has been slowly progressive and interferes with daily tasks. She denies smoking or alcohol use. Family history is irrelevant. Vital signs include: temperature 38.1°C (100.5°F), blood pressure 115/72 mm Hg, and pulse 99/min. Physical examination reveals non-pitting edema of the entire right leg. The overlying skin is rough, thick and indurated. The left leg is normal in size and shape. Which of the following is the most likely cause of this patient condition?
- A. Obstruction of lymphatic channels (Correct Answer)
- B. Hypoalbuminemia
- C. Lymphatic hypoplasia
- D. Venous thromboembolism
- E. Persistent elevation of venous pressures
Thoracic duct and right lymphatic duct Explanation: ***Obstruction of lymphatic channels***
- The patient's history of travel to **Kenya**, along with **progressive, non-pitting edema** of the entire right leg and **rough, thick, indurated skin**, strongly suggests **filariasis**, a parasitic infection that obstructs lymphatic channels.
- **Obstruction of lymphatic channels** leads to **lymphedema**, which characteristically presents with the described symptoms and skin changes (e.g., **elephantiasis**).
*Hypoalbuminemia*
- **Hypoalbuminemia** typically causes **generalized, pitting edema** due to decreased plasma oncotic pressure, not localized, non-pitting edema in a single limb.
- There are no clinical signs to suggest **hepatic** or **renal dysfunction** that would cause significant hypoalbuminemia.
*Lymphatic hypoplasia*
- **Lymphatic hypoplasia** (primary lymphedema) is usually congenital or develops in early life and would not typically manifest acutely after travel in a 39-year-old.
- While it causes lymphedema, the travel history points to an acquired cause rather than a congenital defect.
*Venous thromboembolism*
- **Venous thromboembolism** (DVT) typically presents with acute onset of **painful, edematous** limb, often with **pitting edema**, and can be associated with warmth and erythema.
- The **slowly progressive** nature of the swelling over 4 months and **non-pitting edema** are less consistent with acute DVT.
*Persistent elevation of venous pressures*
- **Persistent elevation of venous pressures** (e.g., chronic venous insufficiency) leads to **pitting edema**, skin discoloration (**hyperpigmentation**), and **ulcerations**, not the rough, thick, indurated skin seen in this case.
- This condition is also typically associated with factors like prolonged standing or obesity, which are not mentioned here.
Thoracic duct and right lymphatic duct US Medical PG Question 8: A 72-year-old woman is brought to the emergency department because of lethargy and weakness for the past 5 days. During this period, she has had a headache that worsens when she leans forward or lies down. Her arms and face have appeared swollen over the past 2 weeks. She has a history of hypertension and invasive ductal carcinoma of the left breast. She underwent radical amputation of the left breast followed by radiation therapy 4 years ago. She has smoked two packs of cigarettes daily for 40 years. Current medications include aspirin, hydrochlorothiazide, and tamoxifen. Her temperature is 37.2°C (99°F), pulse is 103/min, and blood pressure is 98/56 mm Hg. Examination shows jugular venous distention, a mastectomy scar over the left thorax, and engorged veins on the anterior chest wall. There is no axillary or cervical lymphadenopathy. There is 1+ pitting edema in both arms. Which of the following is the most likely cause of this patient's symptoms?
- A. Pulmonary embolism
- B. Pulmonary tuberculosis
- C. Lung cancer (Correct Answer)
- D. Nephrotic syndrome
- E. Constrictive pericarditis
Thoracic duct and right lymphatic duct Explanation: ***Lung cancer***
- The patient's history of **heavy smoking** and prior **breast cancer with radiation therapy** significantly increases her risk for developing **lung cancer**.
- Symptoms like **headache worsened by bending/lying down**, **facial/arm swelling**, **jugular venous distention**, and **engorged chest wall veins** are classic signs of **superior vena cava (SVC syndrome)**, commonly caused by lung cancer compressing the SVC.
*Pulmonary embolism*
- This typically presents with **acute onset dyspnea**, **pleuritic chest pain**, and **tachycardia**, often without the progressive facial and arm swelling or engorged chest veins seen here.
- While a possibility in a bedridden patient, the constellation of symptoms strongly points away from a primary pulmonary embolism.
*Pulmonary tuberculosis*
- Characterized by **chronic cough**, **fever**, **night sweats**, and **weight loss**, symptoms not predominantly featured in this patient's presentation.
- While it can cause lymphadenopathy and venous obstruction in rare cases, the patient's risk factors and specific symptoms are more indicative of malignancy.
*Nephrotic syndrome*
- Primarily causes widespread **edema** (anasarca) due to **severe proteinuria** and **hypoalbuminemia**, which would present as generalized swelling rather than localized facial and arm swelling with prominent venous engorgement.
- It would not typically explain the headache worsened by position or localized SVC syndrome signs.
*Constrictive pericarditis*
- Presents with signs of right-sided heart failure, including **jugular venous distention**, **ascites**, and peripheral edema, but without the specific facial/arm swelling or engorged superficial chest veins characteristic of SVC syndrome.
- It usually results from chronic inflammation of the pericardium and is less likely to cause positional headaches or localized upper body venous obstruction.
Thoracic duct and right lymphatic duct US Medical PG Question 9: A 52-year-old woman presents to the urgent care center with several hours of worsening abdominal discomfort that radiates to the back. The patient also complains of malaise, chills, nausea, and vomiting. Social history is notable for alcoholism. On physical exam, she is febrile to 39.5°C (103.1℉), and she is diffusely tender on abdominal palpation. Other vital signs include a blood pressure of 126/74 mm Hg, heart rate of 74/min, and respiratory rate of 14/min. Complete blood count is notable for 13,500 white blood cells (WBCs), and her complete metabolic panel shows bilirubin of 2.1 and amylase of 3210. Given the following options, what is the most likely diagnosis?
- A. Choledocholithiasis
- B. Cholelithiasis
- C. Acute cholecystitis
- D. Ascending cholangitis
- E. Gallstone pancreatitis (Correct Answer)
Thoracic duct and right lymphatic duct Explanation: ***Gallstone pancreatitis***
- The elevated **amylase** (3210) strongly indicates **acute pancreatitis**, while the **elevated bilirubin** (2.1) suggests **biliary obstruction**, pointing toward a **gallstone etiology** blocking the common bile duct.
- The radiating abdominal pain to the back, nausea, and vomiting along with systemic inflammatory response (fever, leukocytosis) are classic symptoms of **acute pancreatitis**.
- While the patient has a history of alcoholism, the elevated bilirubin is the key finding that suggests **gallstone-induced** rather than alcoholic pancreatitis.
*Choledocholithiasis*
- While an elevated bilirubin suggests **biliary obstruction**, the significantly high **amylase** points primarily to **pancreatic inflammation** rather than just a stone in the common bile duct.
- **Choledocholithiasis** typically causes **biliary colic**, jaundice, and potentially cholangitis, but not the markedly elevated amylase seen here unless it leads to pancreatitis.
*Cholelithiasis*
- **Cholelithiasis** (gallstones) often presents as **biliary colic**, characterized by episodic right upper quadrant pain, but usually without the systemic symptoms or markedly elevated amylase.
- While it's a precursor to other biliary conditions, it doesn't explain the patient's severe generalized symptoms, fever, or the definitive **pancreatitis labs**.
*Acute cholecystitis*
- **Acute cholecystitis** involves inflammation of the **gallbladder**, typically causing **right upper quadrant pain**, fever, and leukocytosis, often with a positive Murphy's sign.
- Although there's fever and leukocytosis, the **diffuse abdominal tenderness** and significantly high **amylase** are more indicative of pancreatitis than isolated gallbladder inflammation.
*Ascending cholangitis*
- **Ascending cholangitis** presents with **Charcot's triad** (fever, right upper quadrant pain, jaundice) or **Reynolds' pentad** (adding hypotension and altered mental status), but the key differentiating factor here is the extremely high amylase.
- While **elevated bilirubin** suggests biliary involvement, the primary pathology indicated by the **amylase level** is pancreatic, not solely biliary infection.
Thoracic duct and right lymphatic duct US Medical PG Question 10: A 2-year-old boy is brought to the emergency department by his mother for evaluation of severe abdominal pain that began one hour ago. On examination, the patient is afebrile and has diffuse rebound tenderness with acute epigastric pain. A stool guaiac test is positive. A small bowel perforation is suspected. What is the embryologic structure that is the underlying cause of this patient’s presentation?
- A. Fibrous cord remnant
- B. Anal membrane
- C. Vermiform appendix
- D. Cloaca
- E. Vitelline duct (Correct Answer)
Thoracic duct and right lymphatic duct Explanation: ***Vitelline duct***
- The symptoms of **severe abdominal pain**, rebound tenderness, epigastric pain, and **positive stool guaiac** (indicating bleeding) in a 2-year-old suggest a bleeding **Meckel's diverticulum**, which is a remnant of the **vitelline duct**.
- **Meckel's diverticulum** is the most common congenital anomaly of the GI tract, often containing **ectopic gastric or pancreatic tissue** that can lead to ulceration, bleeding, or perforation.
*Fibrous cord remnant*
- While a fibrous cord remnant can be associated with the **vitelline duct**, it typically presents with **intestinal obstruction (volvulus or intussusception)** rather than perforation and bleeding from ectopic mucosa.
- A fibrous cord is a potential complication of a persistent **vitelline duct**, but it is not the underlying embryologic structure responsible for ectopic tissue or bleeding.
*Anal membrane*
- The **anal membrane** is involved in the development of the **anus and rectum**.
- Persistence of the **anal membrane** would lead to **anal atresia** or stenosis, causing symptoms of difficult defecation or obstruction, not abdominal pain and perforation like in this case.
*Vermiform appendix*
- The **vermiform appendix** is a lymphoid organ arising from the **cecum**.
- While **appendicitis** can cause severe abdominal pain and perforation, a positive stool guaiac and presentation with ectopic gastric tissue leading to ulceration are not characteristic features.
*Cloaca*
- The **cloaca** is a common embryologic structure that divides into the **urogenital sinus** and the **anorectal canal**.
- Abnormalities of the **cloaca** typically result in complex **anomalies of the urogenital and GI tracts**, such as persistent cloaca with a single perineal opening, not an isolated perforation with bleeding.
More Thoracic duct and right lymphatic duct US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
