Frontal Bone Tuberculous Osteomyelitis with Orbital Involvement: A Case Report
Corresponding Author: Prayas Sethi, Department of Medicine, All India Institute of Medical Sciences (AIIMS), Delhi, India, Phone: +91 9599544679, e-mail: email@example.com
Received on: 08 July 2022; Accepted on: 04 July 2023; Published on: 26 July 2023
Introduction: Tuberculosis (TB) is a significant health problem in developing countries like India. The rising trend of multidrug-resistant (MDR) TB and extrapulmonary TB (EPTB) imposes an additional burden on TB management. Though TB is endemic in India, calvarial TB is very rare, contributes only to 0.2–1.3% of skeletal TB and very limited data is available on calvarial MDR-TB. In this report, we present a rare case of multidrug-resistant tuberculous osteomyelitis affecting the frontal bone and involving the orbit in a young boy.
Case description: we present a case of a 14-year-old boy presented with a 3-month history of a gradually progressive, painless swelling in the scalp, located just above the forehead on the left side. additionally, he reported a 1-month history of swelling in the left eyelid. He also had history of fever, evening rise of temperature, loss of appetite and loss of weight of 4 kg over 3 months.
On examination, there was a fluctuant swelling of 6 x 7 cm in left side of the forehead, without any signs of inflammation or sinuses. The left eyelid was swollen with yellowish material inside, leading to severe mechanical ptosis. The right eye was normal. Systemic examination was normal.
On investigation, CECT revealed focal area of osteolysis and erosion in the left half of the frontal bone with osteolytic extension into the roof and lateral wall of the left orbit along with adjacent interconnecting epidural and subgaleal collection. GeneXpert ULTRA from the aspirated pus detected Mycobacterium tuberculosis and Rifampicin resistance. Later TB culture confirmed the presence of Mycobacterium tuberculosis and the line probe assay detected Rifampicin resistance and high-level Isoniazid resistance.
Hence, a definitive diagnosis of multidrug resistant tuberculous osteomyelitis affecting the left frontal bone with orbital involvement was made. The patient showed significant clinical improvement with bedaquiline-based oral longer MDR-TB regimen without any surgical intervention.
Discussion: Calvarial tuberculosis is a very rare entitity, but can be managed effectively with proper antituberculous drug regimen. Hence tuberculous osteomyelitis should be considered as a possible diagnosis when encountering lytic lesions of the skull. Maintaining a high index of suspicion, facilitating early diagnosis, and ensuring appropriate treatment is essential for achieving favorable outcomes in patients with calvarial tuberculous osteomyelitis.
How to cite this article: Vaitheeswaran KK, Raja R, Sethi P, et al. Frontal Bone Tuberculous Osteomyelitis with Orbital Involvement: A Case Report. J Postgrad Med Edu Res 2023;57(3):140–143.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient’s parents/legal guardians for publication of the case report details and related images.
Keywords: Calvarial tuberculosis, Case report, Frontal bone tuberculosis, Skull tuberculosis
Tuberculosis (TB) is a common devastating disease caused by the bacillus Mycobacterium tuberculosis and is one the major cause of death worldwide, especially in resource-poor countries. India contributes to the highest burden of TB and DR-TB globally. The Global TB Report 2022 published by WHO estimated that the worldwide prevalence of TB was 10.6 million (95% UI: 9.9–11 million) in 2021, and India contributed 28% to the global burden of TB. The estimated incidence of MDR TB or rifampicin (RIF)—resistant TB was 450,000 (95% UI: 399,000–501,000) in 2021, and India contributed 26% of it. According to the Global TB Report of 2020, the prevalence of extrapulmonary TB (EPTB) worldwide was 16%, corresponding to 1.2 million cases. In India, the India TB Report of 2023 indicated that 24% of EPTB cases were reported, amounting to 0.5 million cases. EPTB imposes a substantial burden, constituting 15–20% of all TB cases in individuals without human immunodeficiency virus (HIV) infection and significantly higher at 40–50% among those with HIV-positive status. Approximately 10% of all EPTB cases are attributed to bone and joint TB, with spinal TB being the prevailing manifestation.1 Skeletal TB represents 1–3% of the overall TB cases. Calvarial TB contributes to 0.2–1.3% of skeletal TB, thus making it very rare.2-4 Calvarial TB can present with atypical symptoms, leading to diagnostic challenges. In this report, we present a rare case of multidrug-resistant (MDR) tuberculous osteomyelitis affecting the frontal bone and involving the orbit in a young boy.
A 14-year-old boy presented with a 3-month history of a gradually progressive, painless swelling in the scalp, located just above the forehead on the left side. Additionally, he reported a 1-month history of swelling in the left eyelid. He was apparently normal 3 months back, and then he developed a small painless swelling in the scalp, just above the forehead on the left side, which was spontaneous in onset without any history of trauma. The swelling progressively increased and slowly migrated downwards to involve the left eyelid. The swollen and droopy eyelid obstructed the left eye’s vision. There was no history of ulcer or discharge. No history of headache, vomiting, or seizure. No history was suggestive of any focal neurological deficit. He also had a history of fever and evening rise of temperature, loss of appetite, and loss of weight of 4 kg over 3 months. He took symptomatic treatment from a nearby hospital for which no documents were available.
On examination, the swelling was 6 × 7 cm in size, fluctuant, and without any signs of inflammation or sinuses. The left eyelid was swollen, and the overlying skin was erythematous and exfoliated with yellowish material inside, leading to severe mechanical ptosis (Fig. 1A). Visible conjunctiva was normal, with no proptosis; however, vision and fundus examination could not be performed. The right eye was normal. Systemic examination was normal.
Routine hematology was normal, and the erythrocyte sedimentation rate was 5 mm at 1 hour. Testing for HIV and venereal disease research laboratory test were negative. X-ray chest and ultrasound of the abdomen were normal. Contrast-enhanced computed tomography (CECT) head and the orbit (Fig. 1) were performed, revealing a focal area of osteolysis and erosion in the left half of the frontal bone with osteolytic extension into the roof and lateral wall of the left orbit. The imaging revealed an adjacent epidural collection measuring approximately 2.0 × 1.6 × 0.9 cm (volume 1.5 cc) along the left frontal lobe, as well as an extracranial subgaleal collection measuring around 4.3 × 2.3 × 1.2 cm (volume 6.5 cc). These collections were interconnected through an osteolytic defect and displayed peripheral rim enhancement. Specks of the osteolytic bony fragment were seen within the collections. The epidural collection was causing effacement of underlying sulcal spaces; however, no significant underlying parenchymal edema or midline shift was seen. An additional peripherally enhancing collection measuring approximately 2.4 × 1.7 × 1.9 cm (with a volume of 4.2 cc) was observed in the superolateral aspect of the left orbit. This collection extended from the bony surface within the superior eyelid to the lateral canthus (Figs 1B to F).
The scalp collection was aspirated under ultrasound guidance for microbiological examination, but Ziehl-Neelsen staining showed no acid-fast bacilli. Still, GeneXpert ULTRA detected Mycobacterium tuberculosis and RIF resistance. The Mycobacteria growth indicator tube (MGIT) liquid culture confirmed the presence of Mycobacterium tuberculosis, and the line probe assay detected RIF resistance and high-level Isoniazid resistance. All other bacteriological microscopy and culture studies yielded negative results. The cytopathological examination showed only necrotic inflammatory exudate and did not suggest any evidence of malignancy. A biopsy was not done as the GeneXpert ULTRA was already positive and suggested TB.
Hence, a definitive diagnosis of MDR tuberculous osteomyelitis affecting the left frontal bone with orbital involvement was reached. After proper pretreatment evaluation, the patient was started on a bedaquiline-based oral longer MDR TB regimen containing bedaquiline, levofloxacin, linezolid, clofazimine, and cycloserine. His parents gave negative consent for surgical drainage of the pus and hence, plan for medical management with close follow-up. After 1 month of anti-TB therapy (ATT), there was a marked reduction in the size of both the swellings observed, demonstrating significant clinical improvement (Fig. 1D).
Skull TB has an estimated incidence of approximately one case/10,000 cases of TB,5 highlighting its exceptionally rare occurrence. The rarity of calvarial TB can be attributed to the limited lymphatic drainage in the skull, which prevents the common lymphatic dissemination observed in other bones. The first report of calvarial TB dates back to 1842 by Reid.6 Typically, this condition primarily affects children, with approximately 50% of cases occurring in individuals under the age of 10 and 75–90% in those under the age of 20.7-9 However, isolated cases of skull TB in the elderly have also been documented.10
The clinical presentation of calvarial TB varies depending on the individual’s immune status. Typically, it manifests as a painless swelling of the scalp and the presence of discharging sinuses, while seizures and motor deficits are rare occurrences.8,9 Our case presented with a painless swelling in the scalp, just above the forehead extending into the left eyelid.
Parietal and frontal bones are usually affected due to high cancellous portions.8,11 Due to this, infants are usually not affected, and occipital and sphenoid bones are rarely affected. Similarly, the left frontal bone was affected in our case.
Calvarial TB commonly arises as a result of hematogenous dissemination from a primary infection located elsewhere in the body. However, the primary focus may not always be evident. Similarly, in our case, no active focus of TB was found in clinical examination and investigations. Direct inoculation of the organism can occur in trauma and surgery.2
In the early stages, the Mycobacterium tuberculosis inoculum enters and becomes established within the marrow of the diploe. Subsequently, the infection progresses to involve both the inner and outer table of the skull, resulting in bone destruction and the formation of granulation tissue. The fibroblasts proliferate and form an encircling layer to restrict the further spread of the infection. If it is not arrested, the infection will spread through either table.12 Commonly, the inner table of the skull is affected first, then the outer table, and finally, perforation occurs. If this process occurs rapidly, sequestration might develop, appearing as “bony sand” on radiography.13 Specks of the osteolytic bony fragment were seen within the collections in our case.
When the infection reaches the outer table of the skull, it typically manifests as scalp swelling or the presence of a discharging sinus. On the other hand, the involvement of the inner table leads to the formation of extradural granulation tissue. The dura serves as a barrier, impeding further spread; however, occasional cases of intradural involvement have been observed.13 A robust immune response slows down the progression of the lesion, restricting its evolution, whereas decreased resistance can result in the rapid formation of subgaleal and extradural collections, as well as the development of fistulas.13 In our case, an epidural collection of 1.5 cc and a subgaleal collection of 6.5 cc was present, and both were communicating through the frontal bone osteolytic defect.
There are no specific imaging criteria available for the diagnosis of tuberculous osteomyelitis. In skull X-rays, early stages may reveal rarefication that progresses to the development of punched-out defects. CT scans of the brain demonstrate bony destruction, assess the extent of involvement in the brain parenchyma and meninges, and identify the presence of extradural soft tissue.8 Magnetic resonance imaging is more sensitive in detecting changes in the meninges and brain parenchyma.9
Circumscribed lytic and sclerotic lesions.
Diffuse TB of the cranium.
Other pathologies that can mimic a similar presentation include pyogenic osteomyelitis, fungal osteomyelitis, aneurysmal bone cysts, eosinophilic granulomas, syphilis, myeloma, hemangioma, and metastases.5,12,16
In calvarial TB, there can be a spread or extension of the infection to adjacent structures such as the orbit, paranasal sinuses, or other calvarial bones.11 However, in our case, CECT revealed a focal area of osteolysis and erosion in the left half of the frontal bone with osteolytic extension into the roof and lateral wall of the left orbit.
The diagnosis of calvarial TB is confirmed through microscopy and culture of infected material. Tissue specimens can be acquired through needle aspiration and/or biopsy techniques. The Xpert Mycobacteriumtuberculosis (MTB)/RIF assay and the more sensitive Xpert ULTRA may be adjuncts to diagnose skeletal TB, with 79 and 91% sensitivity, respectively.17 Even though the Xpert ULTRA is less specific than the Xpert MTB/RIF assay, Xpert ULTRA is likely to offer considerable clinical benefit in the setting of high TB and HIV prevalence. In our case, the diagnosis was confirmed by the GeneXpert ULTRA and the MGIT culture.
Antituberculous therapy is the mainstay of the treatment, with or without surgical intervention. The effectiveness of treatment can be assessed by monitoring the patient’s clinical and radiological response, as well as conducting culture studies. According to the Indian extrapulmonary tuberculosis guidelines for EPTB, the recommended treatment approach involves an extended course of ATT. This consists of a 2-month intensive phase that includes four drugs (isoniazid, RIF, pyrazinamide, and ethambutol), followed by a continuation phase lasting 10–16 months, which is determined based on the patient’s clinical progress.18 In the case of MDR/RR TB, the patient should receive an oral bedaquiline-containing MDR/RR TB regimen course based upon the eligibility criteria for 18–20 months, as per Programmatic Management of DR-TB March 2021 guidelines.19 Urgent surgical intervention is necessary when significant extradural collections are present, causing mass effects and neurological deficits. In such cases, thorough debridement and removal of sequestrum are recommended, particularly for large pus collections in the subgaleal plane and sinus formation.9,15,20,21 Associated secondary infections need treatment with appropriate antibiotics.
In conclusion, tuberculous osteomyelitis should be carefully considered as a possible diagnosis when encountering lytic lesions of the skull, particularly in areas where TB is prevalent. The key to diagnosing this condition lies in the correlation of clinical, radiological, microbiological, and histopathological findings. Maintaining a high index of suspicion, facilitating early diagnosis, and ensuring appropriate treatment is essential for achieving favorable outcomes in patients with tuberculous osteomyelitis.
Dr Karthick Kumar V and Ragu R (Department of Medicine, All India Institute of Medical Sciences, New Delhi) have written the case report. All authors contributed to the literature review and discussion writing.
Arvind Kumar https://orcid.org/0000-0002-9229-1081
Naveet Wig https://orcid.org/0000-0002-6603-601X
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5. Myoung Soo Kim (2012). Osteomyelitis Skull, Baptista Prof Mauricio S. (Ed.), ISBN: 978-953-51-0399-8, In Tech, Available from: http://www.intechopen.com/books/osteomyelitis/skull-osteomyelitis.
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11. Raut AA, Nagar AM, Muzumdar D, et al. Imaging features of calvarial tuberculosis: a study of 42 cases. AJNR Am J Neuroradiol 2004;25(3):409–414.
18. INDEX, TB Guidelines. Guidelines on extrapulmonary tuberculosis for India. Central TB Division. Ministry of Health and Family Welfare, Government of India.
19. PMDT, TB Guidelines. Guidelines for Programmatic Management of Drug-Resistant Tuberculosis in India-2021.
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