L1 Question 1:
Which mycobacterium species is most commonly responsible for disseminated tuberculosis?
- A) Mycobacterium tuberculosis
B) Mycobacterium bovis
C) Mycobacterium kansasii
D) Mycobacterium avium complex
Answer: A) Mycobacterium tuberculosis
Comment:
Mycobacterium tuberculosis is the primary pathogen responsible for disseminated TB, accounting for most cases of hematogenous spread of tuberculosis.
Incorrect Answers:
- B) Mycobacterium bovis can cause zoonotic TB but is far less common in human cases of disseminated TB.
- C) Mycobacterium kansasii is an atypical mycobacterium and does not commonly cause disseminated disease.
- D) Mycobacterium avium complex typically affects immunocompromised patients, such as those with AIDS, and presents with a different clinical pattern.
Reference:
Sharma SK, Mohan A. Extrapulmonary tuberculosis. Indian J Med Res. 2004;120(4):316-353.
L1 Question 02:
Which of the following factors most differentiates Mycobacterium tuberculosis from Mycobacterium bovis in terms of transmission and presentation?
- A) Hematogenous spread predominates in bovis
B) M. bovis is typically ingested and affects the gastrointestinal tract
C) M. tuberculosis only causes pulmonary disease
D) Both cause identical disease patterns
Answer: B) M. bovis is typically ingested and affects the gastrointestinal tract
Comment:
M. bovis is often transmitted through the ingestion of contaminated dairy products, leading to primary involvement of the gastrointestinal tract, whereas M. tuberculosis primarily spreads via the respiratory route.
Incorrect Answers:
- *A) Hematogenous spread can occur with both species but is more characteristic of M. tuberculosis.
- *C) M. tuberculosis can also affect multiple organs beyond the lungs in disseminated TB.
- D) The patterns of disease differ based on the route of transmission and primary organ involvement.
Reference:
Grange JM, Yates MD. Zoonotic aspects of Mycobacterium bovis infection. J Appl Bacteriol. 1990;68(6):477-484.
L1 Question 03:
What distinguishes disseminated TB from miliary TB?
- A) Disseminated TB involves peritoneal spread while miliary TB is always hematogenous
B) Miliary TB shows a classic micronodular lung pattern on CXR
C) Disseminated TB only affects solid organs
D) Miliary TB is more common in immunocompetent patients
Answer: B) Miliary TB shows a classic micronodular lung pattern on CXR
Comment:
Miliary TB is a form of disseminated TB where the disease spreads hematogenously, often producing a classic micronodular lung pattern on imaging.
Incorrect Answers:
- A) Disseminated TB can be both hematogenous and transperitoneal.
- C) Disseminated TB affects both solid organs and serosal surfaces.
- D) Miliary TB is more common in immunocompromised individuals.
Reference:
Sharma SK, Mohan A. Miliary tuberculosis. Clin Chest Med. 2019;40(4):705-719.
L2 Question 4:
A 35-year-old male presents with persistent fever, night sweats, and weight loss. CXR reveals diffuse micronodular opacities throughout both lungs. What is the most likely diagnosis?
- A) Disseminated tuberculosis
B) Sarcoidosis
C) Miliary tuberculosis
D) Metastatic cancer
Answer:
C) Miliary tuberculosis
Comment:
Miliary tuberculosis is the most likely diagnosis due to the classic presentation of diffuse micronodular opacities on CXR combined with constitutional symptoms. The term “miliary” specifically describes the hematogenous spread of Mycobacterium tuberculosis, resulting in a characteristic “millet seed” pattern on imaging. Disseminated TB, though related, refers to more widespread systemic involvement beyond a purely hematogenous spread pattern.
Incorrect Answers:
- A) Disseminated tuberculosis: While disseminated TB can also affect multiple organs, the term “miliary TB” specifically describes the hematogenous spread leading to diffuse pulmonary nodules.
- B) Sarcoidosis: Sarcoidosis more commonly presents with bilateral hilar lymphadenopathy and perilymphatic nodules, not diffuse micronodules.
- D) Metastatic cancer: Although metastatic cancer can cause multiple nodules, it typically lacks the uniform micronodular distribution seen in miliary TB and often presents with larger, variable nodules.
Reference:
Sharma SK, Mohan A. Miliary tuberculosis: New insights into an old disease. Lancet Infect Dis. 2019;19(2):e131-e141.
L1 Question 5:
What is the primary difference between miliary TB and disseminated TB?
- A) Miliary TB is limited to the lungs, while disseminated TB involves multiple organs.
B) Miliary TB results from direct extension, while disseminated TB involves hematogenous spread.
C) Miliary TB refers to hematogenous spread with a characteristic pattern of tiny nodules.
D) Disseminated TB refers only to peritoneal involvement.
Answer: C) Miliary TB refers to hematogenous spread with a characteristic pattern of tiny nodules.
Comment:
Miliary TB occurs when TB bacilli spread hematogenously, leading to numerous small nodules, often throughout the lungs and sometimes multiple organs. Disseminated TB can involve both hematogenous and direct spread.
Incorrect Answers:
- A) Miliary TB can affect multiple organs and is not limited to the lungs.
- B) Both forms can involve hematogenous spread, but miliary TB specifically presents with small, uniform nodules.
- D) Disseminated TB can involve any organ, not just the peritoneum.
Reference:
Burrill J et al. Radiological features of extra-pulmonary tuberculosis. Radiographics. 2007;27(5):1255-1273.
L2 Question 6:
Which laboratory test provides the definitive diagnosis of active TB?
- A) Sputum AFB smear
B) Quantiferon Gold
C) Mycobacterial culture
D) Chest X-ray
Answer: C) Mycobacterial culture
Comment:
Mycobacterial culture is the gold standard for diagnosing active TB, but it may take up to 6-8 weeks due to the slow growth rate of Mycobacterium tuberculosis.
Incorrect Answers:
- A) Sputum smear microscopy has lower sensitivity.
- B) Quantiferon Gold detects latent TB, not active disease.
- D) CXR is supportive but not confirmatory.
Reference:
Forbes BA et al. Diagnostic strategies for tuberculosis. Clin Microbiol Rev. 2018;31(1):e00042-
L2 Question 7:
A 50-year-old patient with HIV presents with fever, weight loss, and night sweats. Which of the following tests should be ordered to confirm active disseminated TB?
(Select all that apply)
- A) Blood culture for mycobacteria
B) Sputum GeneXpert MTB/RIF
C) Bone marrow biopsy
D) Chest X-ray
Answer: A, B, C
Comment:
Blood cultures for mycobacteria, GeneXpert, and bone marrow biopsy can all confirm active TB in disseminated cases, especially in immunocompromised patients.
Incorrect Answer:
- D) CXR can suggest disease but does not confirm it.
Reference:
Lawn SD et al. Diagnostic approaches for HIV-associated tuberculosis. Lancet Infect Dis. 2011;11(3):203-212.
L2 Question 8:
Which test is the most appropriate to confirm latent TB infection?
- A) Quantiferon-TB Gold Test
B) Sputum smear microscopy
C) Chest X-ray
D) PCR from pleural fluid
Answer: A) Quantiferon-TB Gold Test
Comment:
Quantiferon-TB Gold is an interferon-gamma release assay (IGRA) used for diagnosing latent TB infection.
Incorrect Answers:
- B) Sputum smear is used for active TB, not latent infection.
- C) CXR can suggest active disease but cannot confirm latent infection.
- D) PCR is more specific for active TB in fluid analysis.
Reference:
Pai M et al. Interferon-gamma assays in the immunodiagnosis of tuberculosis. Lancet Infect Dis. 2008;8(3):219-229.
L2 Question 9:
Which of the following tests is most specific for diagnosing active disseminated TB? (Multiple answers can be correct)
- A) Sputum acid-fast bacilli (AFB) smear
B) TB skin test
C) Interferon-Gamma Release Assay (IGRA)
D) Mycobacterial culture from biopsy tissue
Answer: A) Sputum AFB smear, D) Mycobacterial culture from biopsy tissue
Comment:
AFB smear and biopsy cultures are the most specific tests for diagnosing active TB infection, whereas TB skin tests and IGRA primarily indicate exposure.
Incorrect Answers:
- B) TB skin tests can yield false positives in previously vaccinated individuals.
- C) IGRA tests cannot distinguish between latent and active TB.
Reference:
Lewinsohn DM et al. ATS/IDSA/CDC Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children. Clin Infect Dis. 2017;64(2):111-115.
L2 Question 10:
A 60-year-old male with a history of unpasteurized dairy consumption presents with colonic thickening and necrotic mesenteric nodes. What is the most likely diagnosis?
- A) Crohn’s Disease
B) Mycobacterium bovis infection
C) Ulcerative colitis
D) Peritoneal carcinomatosis
Answer: B) Mycobacterium bovis infection
Comment:
M. bovis commonly affects the GI tract and can be contracted through unpasteurized dairy products.
Incorrect Answers:
- A, C) Inflammatory bowel diseases typically show continuous mucosal inflammation and skip lesions.
- D) Carcinomatosis rarely presents with necrotic lymph nodes.
Reference:
Paustian FF et al. Gastrointestinal tuberculosis and Mycobacterium bovis infection. AJR. 1985;144:285-290.
L2 Question 11:
What imaging finding is most specific for hepatic TB in a patient with disseminated disease?
- A) Diffuse hepatomegaly
B) Multiple subcapsular nodules
C) Portal venous thrombosis
D) Homogeneous liver enhancement
Answer: B) Multiple subcapsular nodules
Comment:
Subcapsular nodules are a hallmark of hepatic TB and often represent granulomatous spread.
Incorrect Answers:
- A) Hepatomegaly is non-specific.
- C) Portal thrombosis can be seen in cirrhosis or malignancy.
- D) Homogeneous enhancement is not typical for TB.
Reference:
Sharma SK et al. Imaging of hepatic TB. Radiographics. 2015;35:1232-1241.
L2 Question 12:
Which of the following imaging findings is most characteristic of splenic involvement in disseminated TB?
- A) Hypodense nodules
B) Multiple calcifications
C) Homogeneous splenomegaly
D) Single cystic lesion
Answer: A) Hypodense nodules
Comment:
Splenic involvement in disseminated TB often presents with multiple hypodense nodules, representing granulomas.
Incorrect Answers:
- B) Calcifications are rare in acute TB but can occur in chronic cases.
- C) Homogeneous splenomegaly is non-specific and seen in various conditions like lymphoma.
- D) Single cystic lesions are not typical for TB.
Reference:
Sharma SK et al. Radiologic patterns of extrapulmonary tuberculosis. Radiographics. 2015;35(5):1232-1241.
L2 Question 13:
Which of the following imaging features would most likely be seen in colonic involvement due to Mycobacterium bovis infection?
- A) Cecal thickening with necrotic mesenteric lymph nodes
B) Extensive peritoneal nodularity with ascites
C) Diffuse hepatosplenomegaly
D) Miliary nodules throughout the lungs
Answer: A) Cecal thickening with necrotic mesenteric lymph nodes
Comment:
Mycobacterium bovis can be contracted through the ingestion of unpasteurized dairy products and often affects the gastrointestinal tract, particularly the cecum, leading to thickening and necrotic mesenteric lymphadenopathy.
Incorrect Answers:
- B) Peritoneal nodularity with ascites is more typical of peritoneal TB rather than M. bovis infection.
- C) Hepatosplenomegaly is non-specific and can occur in other infectious diseases, including disseminated TB.
- *D) Miliary nodules in the lungs are more consistent with hematogenous spread from M. tuberculosis rather than M. bovis.
Reference:
Paustian FF, Fink GH. Gastrointestinal tuberculosis: Diagnostic features and management. AJR Am J Roentgenol. 1985;144(2):285-290.
L2 Question 14:
What is the most likely mechanism for hepatic capsular involvement in disseminated TB?
- A) Direct spread from pulmonary lesions
B) Hematogenous spread
C) Retrograde lymphatic spread
D) Secondary to peritoneal involvement
Answer:
D) Secondary to peritoneal involvement
Comment:
Hepatic capsular involvement in disseminated TB commonly occurs due to direct peritoneal seeding rather than hematogenous spread. The peritoneum often serves as a primary site of infection in extrapulmonary TB, with direct extension to the hepatic capsule.
Incorrect Answers:
- A) Direct spread from pulmonary lesions: Pulmonary lesions in TB typically lead to hematogenous rather than direct spread to the liver.
- B) Hematogenous spread: Hematogenous dissemination can cause miliary liver involvement but does not usually result in capsular involvement specifically.
- C) Retrograde lymphatic spread: Retrograde lymphatic spread can affect nodes but is less common for capsular involvement.
Reference:
Maliwan N, et al. Hepatic tuberculosis: A diagnostic challenge. Radiographics. 2018;38(3):761-773.
L2 Question 14:
Which imaging finding is most suggestive of disseminated TB in the liver?
- A) Large solitary hepatic mass
B) Multiple small hypodense nodules
C) Hepatic calcifications
D) Diffuse hepatomegaly
Answer: B) Multiple small hypodense nodules
Comment:
Multiple hypodense hepatic nodules are characteristic of disseminated TB, often with subcapsular involvement.
Incorrect Answers:
- A) Large solitary masses are more typical of metastases or primary hepatic tumors.
- C) Calcifications suggest a more chronic or healed TB infection.
- D) Diffuse hepatomegaly is non-specific.
Reference:
Maliwan N et al. Hepatic tuberculosis: A diagnostic challenge. Radiographics. 2018;38(3):761-773.
L2 Question 15:
Which of the following is a common manifestation of hepatic involvement in disseminated TB?
- A) Capsular enhancement with nodular liver lesions
B) Diffuse hepatomegaly without focal lesions
C) Cystic liver lesions
D) Single large hepatic abscess
Answer: A) Capsular enhancement with nodular liver lesions
Comment:
Disseminated TB often involves the liver with capsular enhancement and nodular lesions, often subcapsular in location.
Incorrect Answers:
- B) Diffuse hepatomegaly is non-specific and not characteristic of TB.
- C) Cystic lesions are more typical of hydatid disease than TB.
- D) Single large abscesses are more indicative of pyogenic or amebic liver abscesses.
Reference:
Maliwan N et al. Hepatic tuberculosis: A diagnostic challenge. Radiographics. 2018;38(3):761-773.
L2 Question 16: :
Which imaging feature is most characteristic of peritoneal involvement in disseminated TB?
- A) Hepatomegaly
B) Ascites with peritoneal enhancement
C) Calcified granulomas in the lungs
D) Splenic infarcts
Answer: B) Ascites with peritoneal enhancement
Comment:
Ascites with smooth peritoneal thickening and enhancement is a classic imaging feature in peritoneal tuberculosis, often referred to as “omental caking.”
Incorrect Answers:
- A) Hepatomegaly is non-specific and can occur in other conditions like hepatic metastases.
- C) Calcified granulomas are more typical of healed TB rather than active peritoneal disease.
- D) Splenic infarcts are not characteristic of TB and are more commonly seen in vascular pathologies.
Reference:
Sahn SA, Sharma SK. Abdominal tuberculosis: Imaging findings and diagnostic challenges. AJR Am J Roentgenol. 2011;196(2):325-330.
L2 Question 17:
Which of the following mechanisms can contribute to the spread of disseminated TB? (Multiple answers can be correct)
- A) Hematogenous spread
B) Lymphatic spread
C) Direct extension
D) Transperitoneal spread
Answer: A) Hematogenous spread, B) Lymphatic spread, D) Transperitoneal spread
Comment:
Disseminated TB can spread via hematogenous, lymphatic, and direct peritoneal seeding mechanisms.
Incorrect Answers:
- C) Direct extension is rare in disseminated TB and more typical of locally invasive forms.
Reference:
Sharma SK, Mohan A. Extra-pulmonary tuberculosis. Indian J Med Res. 2004;120(4):316-353.
L1 Question 18:
What is the primary difference between miliary TB and disseminated TB?
- A) Miliary TB is limited to the lungs, while disseminated TB involves multiple organs.
B) Miliary TB results from direct extension, while disseminated TB involves hematogenous spread.
C) Miliary TB refers to hematogenous spread with a characteristic pattern of tiny nodules.
D) Disseminated TB refers only to peritoneal involvement.
Answer: C) Miliary TB refers to hematogenous spread with a characteristic pattern of tiny nodules.
Comment:
Miliary TB occurs when TB bacilli spread hematogenously, leading to numerous small nodules, often throughout the lungs and sometimes multiple organs. Disseminated TB can involve both hematogenous and direct spread.
Incorrect Answers:
- A) Miliary TB can affect multiple organs and is not limited to the lungs.
- B) Both forms can involve hematogenous spread, but miliary TB specifically presents with small, uniform nodules.
- D) Disseminated TB can involve any organ, not just the peritoneum.
Reference:
Burrill J et al. Radiological features of extra-pulmonary tuberculosis. Radiographics. 2007;27(5):1255-1273.
L1 Question 19:Disseminated Dx Radiology
Which imaging feature is most characteristic of peritoneal involvement in disseminated TB?
- A) Hepatomegaly
B) Ascites with peritoneal enhancement
C) Calcified granulomas in the lungs
D) Splenic infarcts
Answer: B) Ascites with peritoneal enhancement
Comment:
Ascites with smooth peritoneal thickening and enhancement is a classic imaging feature in peritoneal tuberculosis, often referred to as “omental caking.”
Incorrect Answers:
- A) Hepatomegaly is non-specific and can occur in other conditions like hepatic metastases.
- C) Calcified granulomas are more typical of healed TB rather than active peritoneal disease.
- D) Splenic infarcts are not characteristic of TB and are more commonly seen in vascular pathologies.
Reference:
Sahn SA, Sharma SK. Abdominal tuberculosis: Imaging findings and diagnostic challenges. AJR Am J Roentgenol. 2011;196(2):325-330.
L2 Question 20:
Which of the following can be a differential diagnosis for omental thickening? (Multiple answers can be correct)
- A) Peritoneal carcinomatosis
B) Primary peritoneal mesothelioma
C) Pseudomyxoma peritonei
D) Tuberculous peritonitis
Answer:
A) Peritoneal carcinomatosis, B) Primary peritoneal mesothelioma, D) Tuberculous peritonitis
Comment:
Omental thickening can occur in several conditions:
- Peritoneal carcinomatosis is a common cause, characterized by irregular, nodular omental thickening.
- Primary peritoneal mesothelioma often involves diffuse omental thickening with ascites.
- Tuberculous peritonitis typically presents with uniform omental thickening, ascites, and peritoneal enhancement, often mimicking malignancy.
Incorrect Answer:
- C) Pseudomyxoma peritonei: Pseudomyxoma peritonei is not a typical cause of omental thickening. Instead, it is characterized by “jelly-like” mucinous deposits in the peritoneal cavity, leading to scalloping of visceral surfaces without significant omental involvement.
Reference:
Sahn SA, Good JT. Radiologic features of tuberculous peritonitis. AJR Am J Roentgenol. 2011;196(2):325-330.
L2 Question 22:
What is the standard duration of treatment for disseminated tuberculosis with first-line anti-tuberculous therapy?
- A) 6 months
B) 9 months
C) 12 months
D) 18 months
Answer: A) 6 months
Comment:
The standard treatment for disseminated TB involves a 6-month regimen consisting of a 2-month intensive phase with isoniazid, rifampin, pyrazinamide, and ethambutol, followed by a 4-month continuation phase with isoniazid and rifampin. Prolongation beyond 6 months is only required in specific cases such as TB meningitis or drug-resistant TB.
Incorrect Answers:
- B, C, D) Extended treatment durations are typically reserved for cases of drug-resistant TB or complications such as meningeal or bone TB.