A 60-year-old man with treated TB 1 year ago presents with low back pain. MRI spine shows a lesion. What is the most appropriate next investigation?

1. A

   A. CECT spine

2. B

   B. Mantoux test

3. C

   C. CT chest

4. D

   D. Biopsy

Appeared in: INI-CET EXAM -2026

Explanation

• The most critical step is to differentiate between recurrent infection (TB) and malignancy (cancer), as their treatments are completely different.
• A biopsy is the only method that provides a definitive tissue diagnosis through histopathology (examining cells) and microbiology (culturing for bacteria).
• Histopathology can identify the characteristic caseating granulomas of TB or the abnormal cells of a tumor.
• Microbiological culture of the biopsy sample can confirm active TB infection and determine which anti-tubercular drugs will be effective.
• Authoritative medical guidelines state that a bone biopsy is essential to confirm the diagnosis of skeletal TB and differentiate it from tumors or other infections.

Why Other Options Were Wrong

• Option A: A CECT scan provides detailed anatomical images but cannot provide a definitive tissue diagnosis. The findings can be similar in both infection and malignancy, so it is not the most appropriate next step for diagnosis.
• Option B: A Mantoux test will likely be positive due to the patient's previous TB infection. It cannot distinguish between a past, treated infection and a current, active one. Therefore, it has no diagnostic value in this specific situation.
• Option C: While a CT chest is a valuable part of the overall workup to look for a primary lung cancer or pulmonary TB, it does not diagnose the spinal lesion itself. The most direct and definitive next step is to investigate the lesion found on the MRI.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Diagnostic workup for a spinal lesion in a patient with a history of tuberculosis as background academic context rather than a clinical decision trigger.
• This scenario highlights a critical diagnostic dilemma. A nurse must understand the importance of obtaining a definitive diagnosis before treatment begins.
• Starting anti-tubercular therapy (ATT) for a patient who actually has cancer would delay life-saving cancer treatment and cause unnecessary drug toxicity.
• Conversely, treating a TB infection with chemotherapy or radiation would be ineffective and could worsen the patient's condition.

How to Approach the Question

• First, analyze the patient's clinical profile: a 60-year-old man with a history of treated TB.
• Identify the key finding: a lesion in the spine found on an MRI.
• Formulate the main differential diagnoses: recurrent TB (Pott's disease) vs. malignancy (metastasis).
• Evaluate each option based on its ability to definitively distinguish between these possibilities.
• Recognize that imaging (CECT) and immunological tests (Mantoux) are not definitive in this context.
• Conclude that a biopsy is the only option that provides a direct tissue diagnosis, which is essential for correct treatment planning.

Concept Tested & Keywords

• Concept Tested: Diagnostic workup for a spinal lesion in a patient with a history of tuberculosis.
• Stem keywords: 60-year-old man, treated TB, low back pain, MRI spine, lesion, next investigation
• Lead-in keywords: most appropriate
• Clinical cues: History of treated TB raises suspicion for recurrence (Pott's disease).
• Clinical cues: Age of 60 years makes malignancy (spinal metastasis) a strong possibility.

Question ID

Qk2EY5KHQw697HNIlecwhM

Copy ID

Reference Book

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1848-1850

E6 Medicine Harrison 22e Part 1 p. 1429-1431