Cervical Myelopathy due to Tubercular Retropharyngeal Abscess

Tuberculosis is the commonest infectious disease in developing country. A retropharyngeal abscess is an immediate life-threatening emergency, with potential for airway compromise and other catastrophic complications. We report the clinical, radiological and histological findings of symptomatic 16 years old girl with the features of cervical cord compression due to retropharyngeal abscess of tubercular origin. The patient improved after surgical management of abscess was done followed by anti-tuberculous drugs. Keyword: Retropharyngeal abscess, extrapulmonary tuberculosis, compressive myelopathy 1. Assistant Professor, Department of Medicine, Dhaka Medical College 2. Honorary Medical Officer, Department of Medicine, Dhaka Medical College Hospital 3. Registrar, Department of Medicine, Dhaka Medical College 4. Associate Professor, Department of Medicine, Dhaka Medical College 5. Professor, Department of Medicine, Shaheed Suhrawardy Medical College Correspondence: Dr. Md. Robed Amin, Assistant Professor, Department of Medicine, Dhaka Medical College. E-mail: robedamin@yahoo.com adjacent tissues. Posterior spread of infection can result in osteomyelitis and erosion of the spinal column, causing vertebral subluxation and spinal cord injury2. The infection itself can evolve into necrotizing fasciitis, sepsis, and death. We report the clinical, radiological and histological findings of symptomatic 16 years old girl with the features of cervical cord compression due to retropharyngeal abscess. Case Report A 16 years old girl was admitted in Dhaka Medical College Hospital with the complaints of pain in neck for 5 months, fever for 5 months and weakness in all four limbs & dysphagia for the last 3 months.Neck pain was associated with gradual stiffness. Pain was intermittent, but its frequency and duration had gradually increased. Fever was low grade, irregular, with evening rise and relieved by sweating with medication. Weakness in all 4 limbs was gradual in onset and progressive in nature associated with decreased sensation of all sensory modality in four limbs. She also complained of dysphagia and breathlessness over the few days during hospital stay. Dysphagia was more for solid food than liquid. Her bowel and bladder habit was normal. On examination, her pulse rate was76 beats/min, BP-110/ 70mmHg, temparature-100°F on admission. Nervous system examination revealed, higher psychic function-normal, functions of all 12 cranial nerves were intact. Motor Functionbulk of muscle of upper limb-wasting of the small muscle of hand with clawing deformity of fingers of both hands. In J MEDICINE 2010; 11 : 180-182

adjacent tissues.Posterior spread of infection can result in osteomyelitis and erosion of the spinal column, causing vertebral subluxation and spinal cord injury 2 .The infection itself can evolve into necrotizing fasciitis, sepsis, and death.
We report the clinical, radiological and histological findings of symptomatic 16 years old girl with the features of cervical cord compression due to retropharyngeal abscess.

Case Report
A 16 years old girl was admitted in Dhaka Medical College Hospital with the complaints of pain in neck for 5 months, fever for 5 months and weakness in all four limbs & dysphagia for the last 3 months.Neck pain was associated with gradual stiffness.Pain was intermittent, but its frequency and duration had gradually increased.Fever was low grade, irregular, with evening rise and relieved by sweating with medication.Weakness in all 4 limbs was gradual in onset and progressive in nature associated with decreased sensation of all sensory modality in four limbs.She also complained of dysphagia and breathlessness over the few days during hospital stay.Dysphagia was more for solid food than liquid.Her bowel and bladder habit was normal.
On examination, her pulse rate was76 beats/min, BP-110/ 70mmHg, temparature-100°F on admission.Nervous system examination revealed, higher psychic function-normal, functions of all 12 cranial nerves were intact.Motor Functionbulk of muscle of upper limb-wasting of the small muscle of hand with clawing deformity of fingers of both hands.In lower limb-reduced symmetrically in both the lower limb.Tone of muscle-increased in all the four limbs.Power of muscle-2/5 in all the four limbs.Jerks exaggerated in all four limbs.Planter extensor bilaterally and clonus present.Sensation is reduced in all four limbs but no definite level.Other systems were unremarkable.
On investigation, Hb-12.6g/dl,ESR-50 mm 1 st hour, total count -65000/mm 3 , neutrophils-58%, lymphocyte-36%.Total platelet count-290000/mm 3 , X-Ray of neck (both view) normal (Figure 1).Chest X-ray was normal.MRI of dorsal spine shows retropharyngeal abscess with epidural extension resulting in corresponding spinal cord compression and compressive myleopathy (Figure 2).Consultation with an ENT specialist was done and exploratoion and drainage was undertaken.A large pocket of pus was present behind the stemocleidomastoid muscle medial to the internal jugular vein.The pus was drained and sent for microbiologic examination.On an acid-fast smear, Mycobacterium tuberculosis bacilli were identified.Biopsy of tissue from posterior pharyngeal wall showed granulomatous inflammation with caseous necrosis consistent with TB.A diagnosis of Pott's disease was established, and the patient was started on antituberculous therapy.She improved rapidly over the next few days.Her neck stiffness decreased and she was able to eat comfortably.But her quadriplegia had poor improvement initially.At second week she started to show improvement with gradual movement of limbs and regaining of sensation.She was discharged with advice of anti TB drug for one year duration with steroid coverage.

Discussion
Retropharyngeal abscess (RPA) is of two types-acute & chronic. 3Acute RPA usually occurs in children below 7 years of age because after 7 years retropharyngeal lymph nodes obliterate.Chronic RPA usually occurs in adult & the cause almost always is tuberculosis.RPA complicated by suppuration in the central nervous system, intra-or extraaxial, is rare. 3Retropharyngeal tuberculous abscess is a rare presentation of tuberculosis, even in a patient with extensive pulmonary tuberculosis.It has been reported that 1% of all patients hospitalized with tuberculosis have skeletal tuberculosis, 4 with only 7% of these having involvement of the cervical spine. 5Infection in Pott's disease originates in the pelvic organs and disseminates hematogenously via Batson's plexus to involve more superior areas of the spine in a watershed fashion. 6This explains why only the most anterior portion of the spine is involved and why Pott's disease is rare in the cervical area.Acute transverse myelopathy complicating a retropharyngeal abscess may be more frequent than epidural spinal abscess and usually affects the thoracic cord.Therefore, the occurrence of acute high cervical transverse myelopathy is rarely encountered.As the abscess expands, it may bulge anteriorly into the airway and cause respiratory obstruction, or it may compress the spinal cord and lead to weakness of the extremities and quadriplegia.
Clinical suspicion for Pott's disease should be high for any patient who presents with a destructive lesion of the spine.Radiographically, the most common finding is an osteolytic lesion with widening of the retropharyngeal soft-tissue space. 7Treatment includes incision and drainage of the abscess under antibiotic and antituberculous treatment cover.Early diagnosis & treatment is vital to prevent the formation or progression of neurological deficit.The need for neuroradiologic diagnostic evaluation is emphasized in order to rule out a surgically treatable lesion.

Fig.- 1 :
Normal finding on X-ray cervical spine lateral view