Surgical cases of Tuberculosis of Central Nervous System

Tubercuolosis (TB) continues to be a major public health concern, especially in developing countries. TB is one of the top 10 causes of death worldwide . In 2016, 10.4 million people fell ill with TB; and 1.7 million died from the disease. In 2016, an estimated 1 million children became ill with TB and 250,000 children died of TB. 
Tuberculosis of central nervous system (CNS) can be treated effectively with anti-tubercular therapy (ATT). ATT duration for treatment of CNS TB is 12 months ( 2 months intensive phase and 10 months continuation phase). Some cases of CNS TB require neurosurgical intervention. I am presenting 3 cases of cranial TB where the presentations were unusual leading to delay in the diagnosis. All these three cases were effectively treated with neurosurgery along with ATT.

Patient 1 was a middle aged female with history of headace of long duration. CT scan of head revealed extradural collection beneath the frontal bone. The frontal bone was thickened. This was unusual as duration of symptom was in years and the bone above the lesion was thickened.

 Surgical image showing  pus coming out of frontal bone bur hole

As intensity of the headadche increased , patient was advised surgery. On craniectomy about 60 ml of pus came out under pressure. Patient became asymptomatic after surgery and ATT.

Patient 2 was a middle aged male with history of trauma and swelling over the vertex of skull about 15 days back. Patient was suspected to have scalp hematoma and swelling and was advised antibiotics and analgesics. CT scan showed a scalp swelling over the cranium. Patient underwent surgery and about 40 mL of pus was drained and it was sent for culture/ sensititivity, Gram stain , AFB stain. It came out positive for Staphylococcus. But, despite of prescribing antibiotic according to sensitivity, wound was not healing. Later, wound was re-explored and remaining pus drained out and bony osteomyelitis of the cranium was evident. Craniectomy of the pariental bone at the vertex was done and sent for histopathological examination. Biopsy was suggestive of tuberculosis.

                                                  Surgical image of the patient showing calvarial osteomyelitis

Patient's surgical wound healed with antibiotic and ATT. He became asymtomatic after taking ATT.

Patient 3 was a child of about 14 year age. He presented in emergency of my Institute with history of headache, vomiting, deterioration of conscious level, weakness of right half of body and recurrent seizures. CT scan of the brain and MRI of brain with contrast revealed intracranial subdural hypodense collections in interhemispheric fissure and left fronto-parietal convexity of brain.

                         Surgical image showing burr hole in the frontal bone and pus coming out of subdural space
Frontal region incision was made and single burr hole made in frontal bone under general anesthesisa. Dura was coagulated and incision made in dura. About 80 mL of thick pus came out under pressure. Patient improved after surgery and ATT.

Many types of neurotuberculosis have been described; most common intracranial forms are tuberculous meningitis and tuberculomas.Tuberculous brain abscess and subdural empyema are extremely rare manifestations of central nervous system tuberculosis. Subdural empyema or collection of pus in the subdural space is mostly pyogenic.  Intracranial tubercular subdural empyema is very rare in pediatric population. Various  diagnostic  modalities  and  treatment options  are  available  for  managing central nervous system tuberculosis (CNS  TB).   But, outcome  remains of CNS TB is poor as clinicians  face  many challenges  in  the  management  of  the  tubercular infection  of  the  brain  and  spinal cord.

Treatment of CNS TB is challenging due to lack of specific biochemical tests and inability to get the pathological sample from deeply located eloquent areas of CNS without causing any neurological deficit. Moreover, it is unnecessary to operate for biopsy in a patient who has presented with a very small granulomatious lesion in brain or spinal cord. In such as situations neuro-radiology helps in managing CNS TB and it may be the only source of establishing diagnosis and evaluating treatment response. Role of radiological investigation has expanded from the initial diagnosis to the therapeutic interventions. In some Muli-drug- resistant (MDR) CNS TB cases, stereotaxy or Ultrasonogram (USG) or CT guided biopsy helps in obtaining pathological sample and drug sensitivity testing. A regular clinical and neuro-radiological follow-up is mandatory during the entire course of anti tuberculous therapy to take prompt decisions to change ATT and to reduce morbidity and mortality associated with CNS TB.

Traditionally, culture for the mycobacterium is considered as gold standard for diagnosis of TB. But,  tuberculin  test,  biochemical  investigations and  AFB  stain  and  culture  of  the  cerebrospinal fluid  or  granulation  tissue  provide  little  support for the management of CNS TB or its sequelae.  There should be high index of suspicion for the CNS TB in a patient who is from an endemic region. There may be extensive tubercular involvement of CNS even  in  absence  of  the  history of pulmonary diseases,  tubercular  contact  or  any  other neurological  deficit.  It is difficult  to assess  the therapeutic response in the early follow up period in view of the lack of sensitive and specific tests. Vigilant clinical observation and imaging studies is required in the early follow up period to identify the  worsening  or  new  emerging  signs  in  the patients  of  CNS  TB.  Imaging  studies  are becoming  the  major  decisive  tools  for  the empirical  therapy  and  early  follow  up  of  the patients to evaluate the therapy.

Intracranial tubercular subdural empyema can be effectively treated with ATT and burr hole evacuation of pus. Close clinical observation, neuroradiological assessment with CT scan or MRI and prompt therapeutic interventions   are  necessary  for starting the empirical anti-tuberculous  therapy and early follow up of the patients to evaluate the therapeutic response. 

 In all these cases pus was negative for Acid Fast Bacillus (AFB). This is very common observation. So, high index of suspicion and close follow up is required in suspected cases of cranial TB. Clinical observation with empirical ATT is key in the management of CNS TB cases.

References

1.       An unusual presentation of neurotuberculosis: subdural empyema . Case report. Cayli SR, Onal C, Kocak A, Onmus SH, Tekinen A. J Neurosurg 2001 Jun; 94(6): 988-91

2.       Global tuberculosis report 2017, WHO ( www.who.int)

3.       Pediatric intracranial subdural empyema caused by Mycobacterium tuberculosis- a case report and review of literature. Banerjee AD, Pandey P, Ambekar S, Chandramouli BA. Child Nerv System. 2010, Aug: 26(8): 117-20.doi 10.1007/s00381-010-1157-3 Epub 2010 May 2

4.       Intracranial tuberculous subdural empyema: case report. Van Dellen A, Nadvi  SS, Nathoo N, Ramdial PK. Neurosurgery 1998, Aug; 43(2), 370-3.

5.        Vijaykumar B, Sarin K, Girija Mohan. Tuberculous brain abscess and subdural empyema in an immunocompetent child: Significance of AFB staining in aspirated pus. Ann Indian Acad Neurol. 2012, Apr-Jun, 15(2):130-133.

6.       Gautam VKS, Khurana S & Singh R. Diagnostic and therapeutic challenges in the surgical management of CNS tuberculosis. International Journal of Medicine and Health Sciences, 2013, Vol-2;Issue-2, 161-169.