Haemophilus parainfluenzae ostemyelitis: A case report and literature review

Abstract

Haemophilus parainfluenzae is a gram-negative coccobacillus commonly found in the normal flora of the mucosal membranes of the upper respiratory tract. It has been rarely reported to cause invasive infection including meningitis, endocarditis, urinary tract infections, soft tissue infections, hepatic abscess, and epidural abscess. Osteomyelitis and septic arthritis caused by Haemophilus parainfluenzae are a rare entity with just a few cases described in the literature. Case Presentation A 72-year-old man presented with a two-days of lower back pain. The pain was constant, non-radiating and worse with movement. He had a history of recurrent low back pain due to a previous L3 compression fracture and recurrent acute sinusitisepisodes. Physical exam was remarkable for tenderness to palpation of paraspinous muscle bilaterally at L3-L5 level, and limited flexion of the back due to pain. CT of the lumbar spine showed chronic changes including compression fracture and retropulsion of L3 vertebral body with moderate to severe narrowing of spinal canal. Despite been sent home with anti-inflammatories and muscle-relaxants, he continued with intractable back pain for the next two months. At this time, erythrocyte sedimentation rate was noted to be 36 mm/h and C-reactive protein 3.8 mg/dL. MRI showed concerning findings for osteomyelitis and discitis. CT guided- aspiration bone biopsy cultures grew Haemophilus parainfluenzae. He was treated with ceftriaxone for 6 weeks with improvement of symptoms. Discussion Bone and joint infections caused by H. Parainfluenzae have rarely been reported in literature. From our review of the literature, most of the cases mentioned in the literature about bone and joint infections cause by H. parainfluenzae were on patients with underlying chronic conditions, bone structural abnormalities, or recent procedure. From these cases hematogenous spread or close contaminated source seems to be the most common routes of infection for Haemophilus parainfluenzae given patients history. In our case, the patient had a recent history of recurrent upper respiratory infections with an underlying bone abnormality that could have served as a reservoir for infection. Although H. parainfluenzae is a rare cause of bone infection, careful evaluation of patient’s history and possible preceding factors for infection should be considered in every patient.