Three Acquired Immunodeficiency Syndrome Patients with Central Nervous System Infection: Diagnostic Approach and Outcome of Treatment
Patients with acquired immunodeficiency syndrome (AIDS) are highly susceptible to opportunistic infections due to their compromised immune systems. The human immunodeficiency virus (HIV), which causes AIDS, is neuropathic, and approximately 10% of AIDS patients initially present with central nervous system (CNS) symptoms. Without treatment, more than 40% of AIDS patients will develop CNS diseases. Diagnosing and treating AIDS patients with intracranial lesions is challenging and primarily relies on clinical experience, laboratory tests, and, when necessary, brain biopsies. This article presents a detailed analysis of three AIDS cases with CNS infections treated at Peking Union Medical College Hospital, focusing on their diagnostic approaches and treatment outcomes.
Background and Clinical Context
From 1985 to 2017, 442 cases of AIDS were admitted to Peking Union Medical College Hospital. Among these, three cases were confirmed to have intracranial infections through cerebrospinal fluid (CSF) analysis and brain biopsies. These cases were selected for further analysis because routine antiretroviral therapy and empirical treatments failed to improve their conditions, necessitating more invasive diagnostic measures. The study was conducted in accordance with the Declaration of Helsinki and approved by the hospital’s Ethics Committee.
Case Presentations
Case 1: Progressive Multifocal Leukoencephalopathy and Toxoplasma Encephalopathy
A 47-year-old woman was diagnosed with AIDS in 2006 following significant weight loss. She developed focal neurological symptoms, including dysphonia and paresthesia. Serological tests revealed positive cytomegalovirus (CMV)-IgG/IgM, and brain MRI showed multiple abnormal intracranial signals. A biopsy of the left frontal lobe confirmed progressive multifocal leukoencephalopathy (PML) combined with toxoplasma encephalopathy. Special staining for Toxoplasma gondii was positive for hexamine silver and periodic acid-Schiff (PAS) stains. The patient was treated with highly active antiretroviral therapy (HAART) and anti-Toxoplasma gondii medications, including trimethoprim (TMP), clindamycin, azithromycin, and compound sulfamethoxazole (SMZco). Despite treatment, her neurological symptoms showed no significant improvement upon discharge.
Case 2: Bacterial CNS Infection
A 25-year-old man presented with motor disturbances and asyndesis in his right limb for three months. CSF analysis showed elevated protein levels, and serology was positive for CMV-IgG. Brain MRI revealed multiple abnormal signals, and a biopsy of the left frontal-temporal lobe identified gram-positive cocci and gram-negative bacilli in the smear. The patient was treated with HAART and anti-infective therapy, including ceftazidime and norvancomycin. His symptoms improved significantly, and he was discharged with a favorable outcome.
Case 3: Tuberculous Meningitis
A 37-year-old man was admitted in 2013 with fever and headache. Initial sputum acid-fast staining was positive, and subsequent CSF analysis confirmed the presence of acid-fast bacilli. CSF bacterial culture also identified Staphylococcus hominis. Although the histopathology results were nonspecific, the patient was diagnosed with tuberculous meningitis based on clinical and laboratory findings. He was treated with HAART and a four-drug anti-tuberculosis regimen, including isoniazid, rifampin, pyrazinamide, and ethambutol. His symptoms improved significantly, and he was discharged with a positive outcome.
Diagnostic Challenges and Approaches
Diagnosing CNS infections in AIDS patients is complex due to the overlapping clinical presentations of various opportunistic infections. Routine serological and CSF tests often provide insufficient information, necessitating more invasive procedures like brain biopsies. In these three cases, biopsies were critical in confirming the diagnoses and guiding treatment. The first case highlighted the importance of special staining techniques, such as hexamine silver and PAS, for identifying Toxoplasma gondii. However, the authors suggested that additional diagnostic methods, such as immunohistochemistry, in situ hybridization, or polymerase chain reaction (PCR), could provide further evidence.
The second and third cases demonstrated the value of biopsy smears and CSF analysis in identifying bacterial and mycobacterial infections. In the third case, the positive sputum and CSF acid-fast staining, combined with the patient’s response to anti-tuberculosis therapy, strongly supported the diagnosis of tuberculous meningitis. This case also underscored the importance of repeated CSF testing, as the initial sample may not always yield definitive results due to the low burden of mycobacteria.
Treatment Outcomes and Recommendations
The treatment outcomes varied among the three cases, reflecting the complexity of managing CNS infections in AIDS patients. In the first case, despite aggressive HAART and anti-Toxoplasma gondii therapy, the patient’s neurological symptoms did not improve. This lack of improvement may be attributed to the dual pathology of PML and toxoplasma encephalopathy, as well as the limited penetration of antiretroviral drugs across the blood-brain barrier. The authors recommend high-dose, high-tolerant HAART regimens containing three or four drugs in the early stages of infection to improve CNS drug levels.
In contrast, the second and third cases showed significant improvement with HAART and targeted anti-infective therapies. The second case demonstrated the effectiveness of broad-spectrum antibiotics in treating bacterial CNS infections, while the third case highlighted the efficacy of anti-tuberculosis therapy in managing tuberculous meningitis. These positive outcomes emphasize the importance of obtaining a specific diagnosis to guide appropriate treatment.
The Role of Brain Biopsy in AIDS Patients with CNS Infections
Brain biopsies play a crucial role in diagnosing CNS infections in AIDS patients, especially when empirical treatments fail. Studies have shown that the diagnostic accuracy of brain biopsies in AIDS patients exceeds 90%. For example, Rosenow et al. reported a 92.3% positive diagnostic rate in 246 cases of stereotactic brain biopsies in AIDS patients with intracranial lesions. Similarly, Zibly et al. reported a 93.75% diagnostic yield. These findings underscore the utility of biopsies in identifying a wide range of cerebral lesions associated with AIDS.
However, biopsies are not without limitations. In some cases, the results may be descriptive or nondiagnostic, as seen in the third case of this study. Additionally, biopsies carry inherent risks, including bleeding and infection, which must be carefully weighed against the potential benefits. The authors advocate for a multidisciplinary approach, combining imaging, serology, CSF analysis, and biopsies, to improve diagnostic accuracy and treatment outcomes.
Conclusion
AIDS patients with CNS infections present significant diagnostic and therapeutic challenges. The three cases discussed in this article illustrate the importance of a comprehensive diagnostic approach, including brain biopsies, in identifying specific pathogens and guiding treatment. While HAART and targeted anti-infective therapies can improve outcomes, the presence of comorbidities and the blood-brain barrier often limit their effectiveness. Early, aggressive treatment and multidisciplinary collaboration are essential to improving the prognosis of these patients.
doi.org/10.1097/CM9.0000000000000507
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