Epidemiology of Spine Infections in Children

Incidence and Prevalence

Spine infections in children

• 0.3 cases per 100,000 persons under age 20 per year: Although recent authors have cited higher rates, the overall incidence for all ages of spinal infection remains roughly 2.4 cases per 100,000 per year but only 0.3 cases per 100,000 per year in persons under the age of 20 years (147, 148).

Spinal epidural abscesses in children

• 0.2–2 per 10,000 total hospital admissions per year all ages: Improved initial evaluations by referring physicians and the use of better imaging diagnostic methods are attributed to the increase in diagnosis (16-18).
• Rare in children: Spinal epidural abscesses remain a rare entity in children, with fewer than 100 cases reported (19, 20). The incidence has been reported as high as 0.60 per 10,000 hospital admissions (21).

Spinal subdural abscesses in children

• Very rare in children: Abscesses of the spinal subdural space are extremely rare in children (24, 25).

Intramedullary spinal cord abscesses in children

• Extremely rare in children: Intramedullary spinal cord abscesses are exceedingly rare in both adults and children. Nevertheless, some epidemiological conclusions may be drawn from the extant (although limited) data. In the largest review of intramedullary spinal cord abscesses in children, Simon et al. found a slight male predominance (55%) with a median age at presentation of 36 months (range, 18 days to 17 years) (64). The male predominance in intramedullary spinal cord abscesses may mirror the known male predominance of dermal sinuses.

Age Distribution

Spine infections in children

• Most common in young children: In children spine infections are most prevalent in the very young, and they tend to be within the disk space. The mean age of diagnosis of spinal infections ranges from 2–7 years (6). Osteomyelitis is rare in children 3 years of age or younger, and diskitis is rare in children older than 8 years of age (4).

Diskitis vs. Osteomyelitis in Children: Shown is the high incidence of diskitis in infants and osteomyelitis occurring predominantly later in childhood (6).

Spinal epidural abscesses in children

• Around 8 years of age: The average pediatric age for spinal epidural abscess is 7.6–8 years (9, 10). However, isolated neonatal cases have been reported (17, 26, 27).

Spinal subdural abscesses in children

• Early in life: Only a few cases of spinal subdural abscesses have been reported (25). The majority of patients usually present as infants, babies, or toddlers.

Intramedullary spinal cord abscesses in children

• Median age of 36 months: In the largest review of intramedullary spinal cord abscesses in children, Simon et al. found a slight male predominance (55%) with a median age at presentation of 36 months (with a range of 18 days to 17 years) (64).

Sex Predilection

Spine infections in children

• 2:1 male:female: There is a 2:1 male:female ratio of spinal infections in children (6).

Spinal epidural abscesses in children

• 2:1 male:female in general population: Older studies found an equal sex ratio in adults, with more recent data indicating a male:female ratio of 1:0.56 (28). The ratio in children has not been established.

Spinal subdural abscesses in children

• Not determined

Intramedullary spinal cord abscesses in children

• 55% male: In the largest review of intramedullary spinal cord abscesses in children, Simon et al. found a slight male predominance (55%) (64). This male predominance may mirror the known male predominance of dermal sinuses.

Geographic Distribution

Spine infections in children

• Mediterranean, Central Asia, and Central and South America: Mediterranean countries, the Balkans, Central Asia, and Central and South America have higher incidences of spinal infections (72). Mycobacterium tuberculosis is the most common cause of granulomatous spondylitis (72). Other infective organisms include parasites, fungi, and Brucella.
• Parasitic infections – developing countries: Cysticercosis is the most common parasitic infection affecting the CNS (73). The infection is caused by Taenia solium larvae and is endemic to developing countries of Latin America, Asia, and Africa. The subarachnoid space is the most common location. However, spinal classification of cysticercosis includes isolated spinal infestation, spinal infestation with multifocal disease, direct spinal extension of intracranial disease, and cervical meningitis with cord degeneration (74).

Spinal epidural abscesses in children

In developing countries, the lack of immunizations and the delay of diagnosis and treatment of bacterial infections lead the causes of spinal epidural abscess. In developed countries, spinal epidural abscesses are mostly related to postoperative or post-procedural infections and the immunocompromised state (22, 23).

• The Americas: Prompt access to health care with readily available antimicrobial therapy and advance diagnostic neuroimaging has improved the diagnosis and treatment of patients with spinal epidural abscess in the U.S. and Canada. Regional differences in the incidence of spinal epidural abscesses in Central and South America result from epidemiological variability in risk factors and comorbidities. Bacteriological profiles have indicated that S. aureus is the predominant organism in these regions, followed by M. tuberculosis and S. epidermidis. In a case report from Chile, Peptostreptococcus sp.. were also identified. Bartonella bacilliformis is another pathogen found in patients with spinal epidural abscesses, the vector of which is a mosquito that is geographically limited to Bolivia, Peru, Ecuador, and Colombia (28).
• Africa: S. aureus and enteric gram-negative bacilli are the most prevalent bacterial causes of epidural abscesses in this region. M. tuberculosis osteomyelitis has also been reported. Alternative diagnostic techniques have been used, such as ultrasonography in neonates and infants. Because of limited access to MRI, the diagnostic technique of choice is CT, which also facilitates preoperative neurosurgical planning (28).
• Eurasia: The incidence of spinal epidural abscesses in Asian countries has increased with injected-drug use; tuberculosis is still a common cause of spinal epidural abscesses in the region because of rising numbers of immunocompromised patients (28). Developed countries in Europe and Asia tend to have epidemiological characteristics and treatment algorithms similar to those of the North Americas (29). Different pathogens like Brucella with a high prevalence in Europe have been described (30).

Spinal subdural abscesses in children

• Unclear if geographic preference: As most of the spinal subdural abscesses are related to the presence of dermal sinuses, there is not an explicit geographical distribution for these cases. With 13 (17%), the United States had the most reported cases in the literature, followed by India with 9 reported (12.3%); Iran 8 (11%); Turkey 8 (11%); and Morocco 7 (9.6%) (73).
• Western hemisphere: In the West, the majority of spinal infections occur in the setting of dysraphic or otherwise congenitally diseased spines.
• Middle East, North Africa, and South Asia: Children from non-Western countries account for a higher percentage of spinal subdural tuberculosis and hydatidosis than their Western peers. Eastern, specifically Middle Eastern, North African, and South Asian countries had much higher percentages of infections in children with normal spines than their counterparts in the West (73).

Risk Factors

Spine infections in children

• Hematogenous spread from infection elsewhere: Sources of infection include the skin, genitourinary tract, gastrointestinal tract, oral cavity, and respiratory tract (76).

Spinal epidural abscesses in children

• One-third associated with a disease: In contrast to adults, only one-third of children with spinal epidural abscesses had underlying diseases (22).
• Immunocompromised state: Spinal epidural abscesses are occasionally associated with immunocompromised states (21, 31). The immunocompromised states of sickle cell anemia, polymyositis, and leukemia, and their associated organisms have been well described (31–33).
• Tuberculosis: A few cases of spinal tubercular epidural abscess have been reported in India (35).
• Osteomyelitis of the spine: Vertebral osteomyelitis, a frequent cause of spinal epidural abscess in adults, precedes the disease less frequently in children (20, 36).
• Trauma: Trauma and hematoma formation have been suggested as predisposing events in the development of spinal epidural abscess in 17–24% of cases in children (20, 37).

Spinal subdural abscesses in children

• Dermal sinus tracts: Abscesses of the spinal subdural space are uncommon, and most occur as extensions of infection in patients with midline congenital dermal sinuses; rarely, blood-borne cases are encountered (24).

Intramedullary spinal cord abscesses in children

• Dermal sinus tracts: 53% of patients with intramedullary spinal cord abscesses had a sinus tract diagnosed either before (37%) or after (13%) presenting with signs of abscess formation (95).
• Hematogenous spread of infection: Infections of the vulva, urinary tract, lungs, middle ear, endocardium, kidney, and sagittal sinus have been reported as sources for hematogenous spread to the spinal cord (64, 95).
• Other: Intramedullary spinal cord abscesses have been reported in association with intramedullary spinal cord tumors, trauma, and bacterial meningitis (64, 95, 121).