A case on streptococcal pneumonia associated with leptomeningitis, osteomyelitis and epidural abscess in a patient with AIDS.

Patients with acquired immunodeficiency syndrome (AIDS) are at higher risks of bacterial pneumonia than the general population, and the pathogen is the most commonly involved Streptococcus pneumoniae. We hereby report a case of pneumococcal pneumonia associated with leptomeningitis, osteomyelitis and epidural abscess in a patient with AIDS. He is being successfully treated with ampicillin/sulbactam and clindamycin. And because the pneumococcal infection is usually associated with morbidity and mortality rates in the setting of AIDS, we should consider for pneumococcal vaccinations among the AIDS populations.

Introduction

Patients with acquired immunodeficiency syndrome (AIDS) are exposed to multiple opportunistic infections. In the United States, the most common AIDS-related opportunistic infections recorded were Pneumocystis carinii pneumonia, Mycobacterium avium complex disease and esophageal candidiasis1, while in Thailand, tuberculosis was the most common cause. In Korea, the incidence of candidiasis has been reported as being higher than in the West2, and in recent years, AIDS patients with esophageal stenosis caused by candidiasis and retroperitoneal tuberculosis lymphadenopathy have been reported. In sub-Saharan Africa, tuberculosis, bacterial infections and malaria were the most common serious infections diagnosed in individuals with AIDS, and among bacterial infections a high prevalence of Streptococcus pneumoniae infection was found3.

One of risk factors for pneumococcal infection is an immune deficiency disease (e.g., human immunodeficiency virus [HIV]). And pneumococcal infection is associated with morbidity and mortality in patients with AIDS. We report the case of 53-year-old Korean male with AIDS and pneumococcal pneumonia in addition to leptomeningitis, osteomyelitis, and epidural abscess. He was successfully treated with appropriate antibiotics.

Case Report

A 53-year-old male presented with cough, sputum, and headache for 2 weeks.

Five years previously, he had been diagnosed with HIV. He noted the onset of cough, sputum, and headache. The cough worsened, his sputum turned more yellowish and headaches accompanied by neck stiffness were related to coughing.

Over the first five years following the diagnosis of HIV, he was treated with antiretroviral medications (lamivudine and zidovudine; Combivir, Ritonavir; Norvir, atazanavir sulfate; Reyataz).

1. Physical examination

Vital signs were as follows: temperature, 38.0℃; blood pressure, 110/70 mm Hg; pulse rate, 90/min; respiratory rate, 20/min. He was alert mentally. Auscultation revealed rales in the right lower lung field. A Brudzinski-Kernig test was positive.

2. Laboratory analysis

Complete blood count results were white blood cell 18.43×103/µL (neutrophils 91.3%, lymphocytes 3.5%), hemoglobin 14.0 g/dL, hematocrit 40.3%, and platelets 290×103/µL. Serum chemistry showed blood urea nitrogen 14 mg/dL, creatinine 0.66 mg/dL, aspartate aminotransferase 25 IU/L, alanine aminotransferase 23 IU/L, total bilirubin 1.92 mg/dL, and C-reactive protein 38.51 mg/dL. Cerebral spinal fluid (CSF) showed a white blood cell count of 108/µL, red blood cell count 0/µL, glucose 53 mg/dL, and protein 123 mg/dL. CSF and sputum bacterial cultures were negative. A CD4 T-cell count of 139/µL and HIV RNA of 20.7 copies/mL were recorded.

3. Radiological findings

Plain chest radiography showed ground glass opacity and consolidation in both lung fields (especially the right lower) (Figure 1A). Contrast-enhanced chest computed tomography showed multiple irregular nodular infiltration in both lungs and patchy consolidation with ground glass opacity of the right middle and lower lung (Figure 1B). Contrast-enhanced cervical spine magnetic resonance imaging (MRI) showed a posterior epidural abscess: a peripheral rim-enhancing lesion at the posterior C2-3 epidural space (Figure 2A); osteomyelitis; mild scanning enhancement of the clivus and cervical spine; early leptomeningitis; and prominent leptomeningeal enhancement (Figure 2B).

Figure 1

Initial lung images. (A) Initial chest X-ray showed ground glass opacity and consolidation on both lung fields (especially the right lower lung field). (B) Initial contrast-enhanced chest computed tomography showed multiple irregular nodular infiltration in both lungs and patchy consolidation with ground glass opacity in the right middle and lower lungs.

Figure 2

Contrast-enhanced cervical spine magnetic resonance imaging. (A) Posterior epidural abscess; peripheral rim enhancing lesion at the posterior epidural space of cervical spine (C2-3) (arrow). (B) Osteomyelitis; mild enhancement in the clivus and scanned cervical spine (circle), early leptomeningitis; prominent leptomeningeal enhancement (arrow).

4. Treatment and prognosis

The patient was administered vancomycin (1 g q 12 hr IV), ceftriaxone (2 g q 24 hr), clindamycin (600 mg q 12 hr) and fluconazole (400 mg q 24 hr). The patient's fever reduced 3 days following admission. His epidural abscess was discussed with the neurosurgeon in our hospital. There were no neurological symptoms, no surgical treatment was performed and antibiotic therapy was maintained. At follow-up 5 days after admission, a plain chest radiograph showed improvement, and S. pneumoniae was detected in two blood cultures that showed sensitivity to most antibiotics. The patient was thus switched from vancomycin plus ceftriaxone to ampicillin (2 g) plus sulbactam (1 g q 6 hr IV). Fifteen days after admission, neck stiffness had improved and cough and sputum production reduced. A plain chest X-ray showed decrease in both ground glass opacity and consolidation in both lung fields (Figure 3A). Twenty-six days after admission, laboratory analysis was as follows: white blood cell count 5.42×103/µL, neutrophils 55.9%, lymphocytes 25.9%, and C-reactive protein 0.26 mg/dL. The patient wished to be discharged, so antibiotic therapy was switched from intravenous to oral (amoxicillin/clavulanate 625 mg PO tid). Since discharge, no recurrence of symptoms or evidence of pneumonia according to plain chest radiography have been observed. One year after discharge, there is no abnormal finding on cervical MRI (Figure 3B).

Figure 3

Follow-up of chest X-ray and cervical spine magnetic resonance. (A) Decreased ground glass opacity and consolidation on both lung fields were noted. (B) There is no abnormal signal nor contrast enhancement in C-spine and leptomeninges.

Discussion

In patients with AIDS, the lung is the site most frequently affected by the disease and, currently, the most frequent pulmonary manifestation in developed countries is bacterial (especially pneumococcal) pneumonia, with the next most frequent being Pneumocystis jiroveci pneumonia. Clinical symptoms include fever, cough and the production of purulent sputum. The symptoms are similar in bacterial and Pneumocystis pneumonia, but acute onset of symptoms suggests a bacterial process4. Factors that increase the risk of invasive pneumococcal disease include alcohol abuse, drug addiction and an HIV-infected population. The literature includes one case of spinal epidural abscess with myelitis and meningitis caused by S. pneumoniae in a young child5. In Korea, one fatal case of S. pneumoniae infection associated with AIDS was reported6.

The incidence of bacterial meningitis has dropped dramatically in the general population since the introduction of vaccines effective against bacterial pathogens such as S. pneumoniae, Neisseria gonorrhoeae, and Haemophilus influenzae. However, S. pneumoniae is the most common strain involved in bacterial meningitis in patients with AIDS, with an incidence 150-fold that of the general population. The therapeutic regimen of choice for pneumococcal meningitis in adults with AIDS is ampicillin plus ceftazidime plus vancomycin. Adjuvant therapy with corticosteroids reduces mortality among adults in the general population, but is not recommend for patients with AIDS7.

The mortality rate for osteomyelitis is over 20% in patients with AIDS. In particular, this rate is higher in patients with both AIDS and one or more artificial joints. In most cases of osteomyelitis in patients with AIDS, pathogens were disseminated from septic arthritis, the most common being Staphylococcus aureus and S. pneumoniae. MRI is the most sensitive and specific method for the detection of osteomyelitis (sensitivity 82% to 100%, specificity 75% to 96%)8. Definitive diagnosis is made by bone biopsy and culture, and blood cultures may be positive in cases of bacterial osteomyelitis resulting from haematogenous spread. In addition to surgical treatment, cases of acute osteomyelitis can be treated with antibiotic therapy alone, and the key to successful management is early diagnosis9,10.

Spinal epidural abscess empyema is a rare condition that usually occurs secondary to metastatic infection such as osteomyelitis, and is more common in patients with AIDS. Therefore, in patients with spinal infection, immunosuppressive diseases such as AIDS should also be considered. Diagnosis of spinal infection requires the analysis of cerebrospinal fluid and MRI. An early surgical approach should be considered in the event of complication by compressive myelopathy8.

In the present case, who had no history of pneumococcal vaccination, the patient presented with upper respiratory symptoms diagnosed as pneumonia complicated by leptomeningitis, osteomyelitis and epidural abscess, as confirmed by MRI. S. pneumoniae, as detected by blood culture, can cause upper and lower respiratory tract infections, meningitis, bacteraemia and/or invasive infections. A review of the literature allows identification of the main risk factors: congestive cardiac failure, diabetes mellitus, chronic lung disease and immunodeficiency (including those with AIDS). Infection due to S. pneumoniae is more frequent and more severe in such patients11. In regard to treatment of streptococcal infections, patients with AIDS receive the same as the general population, but AIDS is the main risk factor for streptococcal infections and mortality is high in these patients compared with the general population. Therefore, HIV-infected adults with a CD4+ count of >200 cells/µL should be administered a single dose of 23-valent polysaccharide pneumococcal vaccine unless they had received this vaccine during the previous 5 years12. One recent report discusses the protective effect of 7-valent conjugated vaccine in severe pneumococcal infections in HIV-infected patients13. Community-acquired pneumonia caused by S. pneumoniae is an important public health problem, especially in immunosuppressive diseases such as AIDS. Highly active antiretroviral therapy has led to improved survival rates in patients with AIDS, and thus vaccination is recommended to reduce the incidence of pneumococcal infections in patients with AIDS. More research is needed on the effects of vaccination.