An Unusual Case of Acute Sarcoidosis Triggered by Latent Tuberculosis: Diagnostic and Therapeutic Challenges

An Unusual Case of Acute Sarcoidosis Triggered by Latent Tuberculosis: Diagnostic and Therapeutic Challenges

Panigrahi SUBHANKAR^1*, Yadav PRIYANKA²¹Medical Officer, Department of Medical Oncology, Bagchi Sri Shankara Cancer Research Institute, Bhubaneswar, India
²Medical officer, Department of emergency medicine, Manmohan memorial institute of medical sciences, Manmohan hospital Kathmandu, Nepal

Received Date: March 03, 2025; Accepted Date: March 21, 2025; Published Date: April 17, 2025;
^*Corresponding author: Panigrahi SUBHANKAR, Medical Officer, Department of Medical Oncology, Bagchi Sri Shankara Cancer Research Institute, Bhubaneswar, India; Email: psubhankar553@gmail.com

Citation: Subhankar P, Priyanka Y (2025) An Unusual Case of Acute Sarcoidosis Triggered by Latent Tuberculosis: Diagnostic and Therapeutic Challenges. Adv Pub Health Com Trop Med: APCTM-214.

DOI: 10.37722/APHCTM.2025101

Abstract

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that can present with clinical features overlapping with tuberculosis (TB). Distinguishing between sarcoidosis and TB is challenging, especially in TB-endemic regions. We present a case of acute sarcoidosis in a 35-year-old male with latent TB, posing unique diagnostic and therapeutic dilemmas. The patient exhibited erythema nodosum, joint pain, and a positive TB Gold test with no pulmonary involvement. Anti-tubercular therapy (ATT) was initiated, leading to significant clinical improvement within two months. This case underscores the need for a comprehensive diagnostic approach to differentiate sarcoidosis from TB and highlights the challenges of managing these coexisting conditions.

Introduction

Sarcoidosis is a systemic inflammatory disease characterized by non-caseating granulomas in affected tissues. While its exact cause remains unknown, various environmental and infectious agents have been hypothesized as potential triggers. The overlap between sarcoidosis and tuberculosis is particularly complex, as both conditions can present with granulomatous inflammation and share immunological features. The possibility of latent TB acting as a trigger for sarcoidosis remains a topic of debate.

Here, we describe an unusual case of acute sarcoidosis in a young male with latent TB. The case highlights key diagnostic challenges, as well as the necessity of an individualized treatment approach to balance the risks of TB activation with effective sarcoidosis management.

Case Presentation

A 35-year-old male presented with a two-month history of bilateral ankle pain, swelling, and erythematous nodular lesions on the shins. His symptoms began with an episode of high-grade fever lasting five days, which resolved spontaneously. This was followed by progressive joint discomfort, particularly in the lower extremities. The patient also reported a mild dry cough for two days but denied systemic symptoms such as weight loss, night sweats, or respiratory distress.

Clinical Findings

On examination, the patient exhibited bilateral erythema nodosum over the anterior shins. There was mild swelling and tenderness over both ankles without evidence of joint effusion. There was no lymphadenopathy, hepatosplenomegaly, or respiratory compromise.

Investigations

A detailed workup was performed, revealing the following findings:

Complete Blood Count (CBC): Normal
C-Reactive Protein (CRP): Mildly elevated (1.07 mg/L)
Angiotensin-Converting Enzyme (ACE): Elevated (71.17 U/L)
HLA-B27: Negative
TB Gold Test (IGRA): Positive
Mantoux Test: Negative
Skin Biopsy: Septal panniculitis with leukocytoclastic vasculitis, consistent with erythema nodosum
Liver Function Tests (LFT): Mildly elevated serum proteins
Chest X-ray & HRCT Thorax: No evidence of pulmonary sarcoidosis or TB-related lung injury
Ultrasound Abdomen: Incidental finding of a 0.9 mm gallstone

Diagnosi

Based on the clinical presentation, laboratory findings, and histopathology, a diagnosis of acute sarcoidosis triggered by latent tuberculosis was established. The positive TB Gold test suggested latent TB infection, while the absence of lung involvement on imaging helped rule out active TB.

Treatment and Follow-Up
Intensive Phase (2 months)

– Rifampicin 150 mg
– Isoniazid 75 mg
– Pyrazinamide 400 mg
– Ethambutol 275 mg

Continuation Phase (4 months)

– Rifampicin + Isoniazid + Ethambutol

Symptomatic Management

– Naproxen for joint pain
– Etoricoxib 90 mg (Selective COX-2 inhibitor)
– Pyridoxine 40 mg

Follow-Up Outcomes

After two months of ATT, the patient demonstrated significant clinical improvement:

– Resolution of bilateral swelling
– Erythema nodosum subsided
– No active symptoms

Discussion
Challenges in Diagnosing Sarcoidosis and TB

Sarcoidosis and TB both involve granulomatous inflammation, making differentiation difficult. Several factors helped guide the diagnosis in this case:

Positive TB Gold Test, but No Lung Involvement– The IGRA test confirmed TB infection, but the absence of lung pathology ruled out active pulmonary TB.
Negative Mantoux Test – This further indicated latent rather than active TB.
Histopathological Findings – The presence of septal panniculitis with leukocytoclastic vasculitis supported sarcoidosis over tuberculosis.
Elevated ACE Levels– Suggestive of sarcoidosis, though not specific.

Conclusion

This case highlights the diagnostic and therapeutic complexities of acute sarcoidosis in a patient with latent tuberculosis. The positive TB Gold test, absence of pulmonary involvement, and histopathological findings helped differentiate the conditions. The successful resolution of symptoms with ATT without corticosteroids reinforces the importance of tailored treatment strategies, particularly in TB-endemic regions. Clinicians must maintain a high index of suspicion and employ a multidisciplinary approach when managing similar cases.

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