A 21 year old farmer from North Central province of Sri Lanka; presented to Teaching Hospital- Kandy, with sudden onset bi lateral lower limb weakness and numbness with urine retention. Three days prior to this event he had had a low grade fever with chills, which subsided without medication. There was no history suggestive of skin ulceration or of trauma. His past medical history had been uneventful and he was a teetotaler and a non smoker. As a paddy farmer he had had repeated exposure to water and soil at work.
On examination, he was afebrile and the skin examination was normal. His pulse rate was 80 bpm with a blood pressure of 120/80 mmHg. Respiratory system and abdomen were clinically normal. Neurological examination revealed flaccid areflexic lower limbs with power of grade zero. He had sensory impairment of all modalities including joint position sensation and vibration; with a sensory level at T 10 and involvement of sphincters. His upper limbs, cranial nerves and higher functions were normal.
His full blood count showed a neutrophil leukocytosis. (White blood cell count - 20.91 × 109, 89% Neutrophils), Erythrocyte sedimentation rate was 120/1st hour and C- reactive protein was 196 mg/dl. His X-ray and Computerized tomography (CT) of the dorsal spine was normal, however CT dorsal spine incidentally revealed an abscess in the left psoas muscle (Figure 1). Magnetic resonance imaging (MRI) scan abdomen and thoracolumbar spine revealed a large multi loculated psoas abscess measuring 29.7 cm × 5.7 cm, which involves the entire length of the left psoas muscle with finger like extensions towards the spine. There was extensive myelitis involving the spinal cord from T4 downwards with foci of T2 weighted (T2W) hyperintensity and meningeal enhancement but definite extension of abscess to the spinal canal or a cord compression could not be seen. There was central canal dilatation in the entire length of the spinal cord (Figure 2). There were no other foci of sepsis noted.
An urgent ultrasound guided aspiration of the psoas abscess was carried out and about 350 cc of pus drained. A sample of pus was grown in both blood agar and Macconkey agar (MA). On blood agar it formed medium sized whitish non haemolytic colonies and on Macconkey agar it was typical non lactose fermenting colonies (NLF). Most of the culture characteristics which are needed for the presumptive identification of Burkholderia pseudomallei were present. When MA plate was kept in room temperature for 24 hours, it gave lactose fermenting colony appearance. The characteristic earthy smell too was present. (Though smelling of the plate is not recommended). When the isolate was gram stained, gram negative bacilli with characteristic safety pin appearance were seen. Biochemical identification was done using API (Analytical Profile Index)-20NE kit. Its diagnosis was given as Burkholderia pseudomallei. Antibiotic susceptibility testing was done by CLSI (Clinical and Laborotary Standards Institute) method. They were sensitive to Ceftazidime and resistant to Gentamicin and Colistin. Diagnosis of melioidosis was made due to the presence of high titres of Burkholderia pseudomallei antibodies and positive polymerase chain reaction (PCR). PCR was done with Burk Lpxo PCR Primer sequence. [BURK-3 F (Forward) 5’- GCG CCG CTC AAT TG TTT C -3’ and BURK-2R (Reverse) 5’- CCA CTC GCG CTT GAG GA].
His blood and urine cultures were negative and the fasting and post prandial sugar levels were normal. His renal function tests, liver function tests, coagulation screen and chest X ray were normal. CT Scan of the head was normal but CT scan of the chest was not performed. Repeat ultrasound scan of the abdomen confirmed complete evacuation of the psoas abscess. Cerebrospinal fluid (CSF) studies in this patient was not attempted because of the risk of introducing organisms into the central nervous system as the MRI could not rule out a definite extension of abscess to the spinal cord. Viral studies to exclude other causes of transverse myelitis were not performed because of the financial constrains and the patient being a previously healthy male, the rarity of existence of dual infections.
He was treated with IV ceftazidime 2 g 8 hourly (120 mg/kg/day) and oral cotrimoxazole 1920 mg twice daily for a period of one month followed by a course of oral cotrimoxazole 1920 mg twice daily together with oral doxycycline 100 mg twice daily until one year. As a treatment for myelitis, three day course of IV methylprednisolone 1 g daily was also continued after aspirating the abscess. Physiotherapy, bowel and bladder care and routine care to prevent pressure sores were arranged from the first day of the illness. Following completion of the course of IV antibiotics patient was transferred to a rehabilitation hospital for supportive care. Even though there was no progression of the illness, the residual neurological deficits including the paraplegia, complete sensory loss and sphincter disturbance persisted.
