Holospinal epidural abscess caused by Streptococcus anginosus group: a literature review

Abstract

Spinal epidural abscess (SEA) usually extends over three to four vertebrae. We present a case of holospinal epidural abscess (HEA) caused by the Streptococcus anginosus group (SAG). A man in his 40s with a 2-week history of fever, back pain, and progressive tetraparesis was referred to us from the local hospital. MRI showed epidural fluid collection from C2 to S1. Blood and pus cultures revealed the presence of SAG. He was treated by emergency laminoplasty, epidural drainage and antibiotic treatment. After the 111st hospital day, his manual muscle test was shown to improve; hence, he was transferred for rehabilitation. According to the previous reports, we identified 12 cases of SEA extending from the cervical spine to the sacrum, including our case. For one-fourth of these cases, SAG was the causative organism of this rare SEA. Therefore, SAG should be considered causative organisms in HEA.

Background

Streptococcus anginosus group (SAG) comprises Streptococcus anginosus, Streptococcus intermedius and Streptococcus constellatus, which are commensal bacteria of the oral cavity, gastrointestinal tract and urogenital tract.¹ These organisms also cause abscesses in the liver, intra-abdominal and brain. Alternatively, S. aureus is responsible for two-thirds of the reported cases of spinal epidural abscess (SEA) and caused by SAG are extremely rare.² In this report, we have described a case of holospinal epidural abscess (HEA) from the cervical spine to the sacrum caused by SAG and review the literature of previous reports.

Case presentation

A man in his 40s without immunosuppressive diseases and dental caries presented to the local hospital with a 2-week history of fever, back pain and progressive tetraparesis. MRI of the cervical spine showed a space occupied lesion from C2 to the upper thoracic spine. The same day, he was referred to our hospital for further management.

At our hospital, his Manual Muscle Testing (MMT), which is rated on a 6-point scale from 0 (no evidence of contractility) to 5 (complete range of motion against gravity with full resistance), was 0 for the upper right limb, 3 for the left upper limb and 0 for the lower limbs. Moreover, he presented sensory disturbances below the C5 level and atonic anal sphincter. The blood test showed that the white cell count was 43.9 ×10⁹/L, C reactive protein was 25.81 mg/dL, and creatinine level was 1.35 mg/dL.

Investigations

The last MRI performed did not include the entire image of the space occupying lesion on the spine. Therefore, MRI of the entire spine was performed and showed epidural fluid collection from C2 to S1 (figure 1). Additionally, plain CT showed abscesses in the left psoas and the right piriformis muscle (figure 2A, B).

Figure 1.

Sagittal T2-weighted MRI of the whole spine revealed epidural fluid collection (arrowhead) from C2 to thoracic level (A) and from thoracic level to S1 (B) performed in our hospital.

Figure 2.

(A) CT revealed left psoas muscle swelling and internal low density area, indicating abscess formation (arrowhead). (B) CT revealed abscess in the right piriformis muscle (circle).

Treatment

On his first hospital day, we performed emergency laminoplasty at C3–7, laminectomy at Th12–L4 and epidural drainage, followed by the administration of the intravenous meropenem and linezolid. On the fourth hospital day, S. intermedius, one of the SAG, grew in blood and pus cultures, and then we discontinued linezolid. On the seventh hospital day, the antibiotic was changed to intravenous ampicillin/sulbactam according to the antibiotic susceptibility result. Despite being sensitive, penicillin was not used because of the high serum potassium level. Finally, on the 45th hospital day, intravenous antibiotics were switched to oral levofloxacin.

Outcome and follow-up

His muscle strength was improved by rehabilitation and weaning. Three months later, his MMT recovered to 4/5 in all limbs, and he could start walking. Then, on the 111st hospital day, he was transferred to a rehabilitation facility.

Discussion

The incidence of SEA was 5.1 cases per 10 000 hospital admissions, the mortality rate was 7%, and 8% of the patients suffered from paralysis.³ Recently, the number of patients with SEA has been increasing due to the ageing population, increasing use of spinal instrumentation and vascular access, and the spread of injection–drug use.⁴ In general, SEA is more likely to occur in the posterior thoracolumbar spine region because the posterior epidural space has a weaker dural-periosteal bond than the anterior. Moreover, the thoracolumbar epidural space is larger and contains more infection-prone fat tissue.⁵ The patients with SEA frequently reported back pain consistent with the site of abscess formation, fever and neurologic symptoms as the disease progressed. MRI is the most superior, non-invasive, and a highly specific diagnostic method. As the surgical approach depends on the extent of the abscess, an accurate assessment of the abscess in MRI is important.

The extent of SEA is usually limited to two regions, and the one which extends from the cervical spine to the sacrum is very rare. We searched PubMed with the terms ‘holospinal epidural abscess’ and ‘panspinal epidural abscess,’ reviewed all the literature, and selected only the cases with HEA confined from the cervical to the sacral region to find 11 cases being reported previously (table 1).^6–15 All the patients were men, the youngest was 5 years old, and the oldest was 73 years old. Including our case, 11 (91.7%) were found to have a fever at the time of examination and 9 (75.0%) had back pain and neurological symptoms. However, previous reports have shown that only 42% of SEA presents neurologic symptoms.³ The reason for the neurologic symptoms may be spread of abscesses to the entire spine, resulting in severe spinal compression. S. aureus was the most common pathogen in HEA, accounting for seven cases (58.3%), followed by SAG, which accounted for three cases (25.0%). Reihsaus et al reported only five cases (0.7%) of SEA by SAG.²

Table 1.

Reported cases of holospinal epidural abscess

Reference	Age	Sex	Range of abscess	Pathogen	Risk factor	Symptoms
						Fever	Back pain	Neurologic
6	69	M	C to S	SAG	Diabetes	Yes	Yes	Yes
7	73	M	C1 to S2	SAG	Diabetes	Yes	Yes	Yes
8	46	M	C1 to S	MSSA	Diabetes	Yes	Yes	Yes
9	19	M	C2 to S	MSSA	None	Yes	Yes	No
10	65	M	C6 to S1	MSSA	Sacral epidural block	Yes	Yes	No
11	>20	M	C3 to S1	MSSA	Intravenous drug use	Yes	Yes	Yes
12	5	M	C1 to S	MRSA	None	Yes	No	Yes
12	51	M	C to S	MRSA	None	No	Yes	No
13	14	M	C1 to S	S. aureus	None	Yes	No	Yes
14	5	M	C4 to S2	Enterococcus sp. Tuberculosis sp. Anaerobic bacteria	None	Yes	No	Yes
15	25	M	C2 to S1	N/A	Crohn’s disease	Yes	Yes	Yes
Present case	40s	M	C2 to S1	SAG	None	Yes	Yes	Yes

MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus; N/A, not available value; SAG, Streptococcus anginosus group.

SAG, gram-positive, and catalase-negative cocci, is known to be a normal human flora. These organisms are known for high abscess-forming capacity and are commonly reported as causative organisms for the abscess of the liver, intra-abdomen and brain.^{16 17} The underlying mechanism of the abscess-forming capacity is not fully understood, but polysaccharide capsules, exothermic exotoxins and hydrolytic enzymes might be contributing factors.¹⁸ As mentioned above, SEA caused by SAG is rare, but if SAG causes infection of the spinal epidural space, the abscess can spread extensively due to the characteristics of SAG. Therefore, SAG should be considered as one of the causative organisms in HEA.

In conclusion, HEA is an infrequently reported form of SEA, but it tends to present with more typical symptoms. Therefore, an entire spine MRI scan should be performed in all suspected cases with HEA. Moreover, because of the high capacity of abscess formation of the causative microorganism, SAG should be considered in HEA cases for timely investigation and proper management.

Learning points.

• Holospinal epidural abscess (HEA) is a very rare disease; if suspected, an MRI of the entire spine is warranted.

• HEA tends to present more typical symptoms, such as fever and neurological symptoms than a usual spinal epidural abscess.

• Streptococcus anginosus group (SAG) is relatively frequent as the causative organisms in HEA, so it is necessary to search for infectious gateway and treatment, taking into account SAG as well.

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