Varsha Rathi¹, Nidhi Singh^2*

¹Professor, ²Junior Resident, Department of Radiodiagnosis, Grant Medical College & JJ Hospitals, Mumbai, Maharashtra, INDIA.

Email: drvpr@hotmail.com , ndhsingh78@gmail.com

Table 1: Diagnosis and frequency of CNS pathologies in HIV patients

In our study 38% ( 08/21) patients with CNS tuberculosis presented with isolated Tuberculous meningitis. Isolated Tuberculomas were seen in equal percentage of patients while 9.5 % (2/21) patients had tuberculous meningitis with tuberculomas. Tubercular abscess was seen in 14.3 % (03/21) cases. 08/21 i.e 38% patients had hydrocephalus, all being communicating hydrocephalus. Vasculitic infarcts were seen in 28.3 % ( 5/21) cases. Other findings like arachnoiditis (1/21) and Pott’s spine (2/21) were seen in 14.2% (03/21) patients.

Table 2: Spectrum of Neurotuberculosis in HIV patients (n =21)

In our study,five cases of toxoplasmosis were encountered. 80% (04/05) patients showed multiple lesions and gangliocapsular region was the most common location. Ring enhancement was seen in 80% (04/05) patients. Blooming on SWI was noted in 60% (03/05) cases. Two patients showed eccentric target lesion like enhancement. All patients showed surrounding edema and mass effect. We did not find meningeal enhancement in any of the patients. Progressive multifocal leukoencephalopathy an opportunistic infection caused by JC virus was seen in eight patients. White matter lesions were asymmetric in distribution and bilateral in all the cases. Sub cortical white matter was the most common location (87.5%) followed by brain stem ( 50%).Single case showed patchy diffusion restriction. None of the lesion showed mass effect or enhancement. Associated cerebral atrophy and ventricular prominence were present in 75% ( 06/08) cases. Three cases of CNS lymphoma are present in our study. All the cases showed multiple lesions. Out these 3 cases 2 were involving supratentorium (periventricular and subcortical white matter). All the lesions were isointense on T1W images. Single case showed hypo to isointense lesions on T2W images and rest were hyperintense on T2W images. Variable enhancement patterns were seen with each case showing homogeneous, ring pattern and heterogeneous enhancement. Two cases showed surrounding edema, while single case showed mass effect. 66.6 %( 02/03) cases showed hyper perfusion on perfusion study.

Total 9 patients had HIV encephalopathy.Bilateral symmetrical lesions were seen in all 9 (100%) patients. Periventricular lesions were seen in 8 (88%) . None of them showed contrast enhancement. Associated cerebral cortical atrophy was seen in 4 (44.5 %) of patients Out of 60 patients, 6 % ( 10/60) showed meningitis. All the cases of meningitis were associated with CNS tuberculosis. We did not come across aseptic meningitis or meningitis due to other opportunistic infections.

In our study 11 (18.3 %) patients had imaging feature suggestive of Infarct. Five patients had infarct secondary to tuberculosis infection.In another five patients etiology of infarct was not clearly established but these patients had no other risk factors such as hypertension, diabetes, hyperlipidemia or smoking. In this particular group in absence of obvious etiological factors and after ruling out other predisposing factors to CV stroke, presumed diagnosis of HIV Vasculopathy was considered.

Table 3: Correlation between CD4 Count and Neurological manifestations

In our study, 37.8% of PML cases had CD4 count under 100, 37.8% between 101-150 and 25.0% cases had CD4 count between 210-205. None of the cases had CD4 counts above 250.60% patients of Toxoplasmosis had CD4 count below 100. None of the patients had CD4 count more than 150.Single case of Cryptococcosis had CD4 count below 50.All three cases of lymphoma had their CD4 count below 150 with one case each in 0-50, 51-100 and 101-150.Among the cases of CNS Tuberculosis, maximum 52.4% (11/21) patients had CD4 counts above 250. Similarly, maximum number of patients with HIV encephalopathy i.e. 77.7% ( 07/09) had CD4 counts above 250.

Case 1: HIV encephalopathy

Figure 1: Flair axial; Figure 2: Post contrast T1 FAT SAT axial

Case 2: Progressive multifocal leukoencephalopathy

               Figure 3: Flair axial                Figure 4: T2WI axial                        Figure 5: T1WI axial        Figure 6: Post contrast T1 axial

Case 3: Tuberculous meningitis with Vasculitic infarcts

    Figure 7: Flair axial           Figure 8: Flair axial               Figure 9: DWI                          Figure 10: ADC

Figure 11: Post contrast T1 FAT SAT; Figure 12: Post contrast flair

Case 4: Tubercular abscess

          Figure 13: Flair axial        Figure 14: Post contrast flair axial                Figure 15: DWI                          Figure 16: ADC

Case 5: Tuberculomas with tubercular meningitis and arachnoiditis

                                  Figure 17: Post contrast Figure 18: Post contrast               Figure 19: Post contrast      Figure 20: Spine post

            T1W1 axial                           T1W1 axial                                           flaire axial            contrast T1 fat sat sagittal

Case 6: Toxoplasmosis

    Figure 21: T2WI axial  Figure 22: Post Contrast flair axial                Figure 23: DWI                                Figure 24: ADC

Case 7: Cryptococcosis

                   Figure 25: Flair axial          Figure 26: T2W1 axial              Figure 27: T1WI axial     Figure 28: Post contrast T1WI

Case 8: Primary CNS lymphoma

          Figure 29: Flair axial               Figure 30: DWI                        Figure 31: ADC       Figure 32: Post contrast T1     Figure 33: Post contrast

              FAT SAT axial                  flair axial

DISCUSSION

This was a cross sectional descriptive study carried out in the Department of Radiodiagnosis at a Tertiary care teaching Institution in Mumbai,India wherein 60 seropositive patients who presented with neurological complains underwent MRI and the imaging findings studied. Most common age group was found to be more than 40 years with 51.6 % of the total study population followed by the age group of 21-40 years which accounted for 45%. Males were affected more commonly than females. Male: Female ratio in patients with neurological involvement is 1.86:1. The most common presenting symptom on admission was fever (41.6%) followed by altered sensorium (33.3%), headache and stroke in 26.6% patients each,dementia (20%) ,convulsions (6.6%) and vomiting found in 6% patients. HIV induced primary neurological illness were present in 25% cases, while opportunistic infections were seen in 60 % cases. Most common opportunistic infection in HIV was Tuberculosis which was present in 58.3% (21/36) cases followed by PML 22%, Toxoplasmosis 14 % and fungal infections 6%. Cryptococcosis was found in only one patient out of total 60 patients. Primary CNS Lymphoma was found in 5% cases. In comparison to previous Indian studies done by HM Rana et al. ⁹ in 2011, Sharma SR et al.¹⁴ in 2017 and S Pawar et al. ¹⁵ in 2017, our study showed higher percentage of CNS manifestations due to primary effects of HIV ( HIV associated Dementia) as well as Progressive Multifocal leukoencephalopathy ( PML). The percentage involvement of Neurotuberculosis was nearly the same. There were lesser cases of fungal pathologies in our study. No case of Neurosyphilis was encountered. When compared to Non Indian studies by Sokolska et al. ²⁰and Berhe et al. ²¹, our study showed lower incidence of Toxoplasmosis and fungal infections and higher incidences of Neurotuberculosis. However, the Percentage involvement of HIV associated dementia is quite comparable. CNS Tuberculosis was the overall most common pathology in our study accounting to 35.0% i.e 21/60 cases. Out of 21 patients with CNS TB, 10 ( 47.6%) patients demonstrated cisternal/ meningeal enhancement. 10 (47.6%) patients showed enhancing parenchymal lesions and tuberculomas and 03 (14.7 %) had tubercular abscesses. Communicating hydrocephalus was present in 08 (38%) of 21. Vasculitic infarcts were seen in 05 (23.8%) cases. Additional findings of arachnoiditis (1/21) and tubercular spondylodiscitis with para vertebral abscesses (2/21) were also appreciated in few cases. The spectrum of CNS tuberculosis in HIV patients seen in our study is comparable to multiple previous studies like Sarosh et al. ²³ Michelle Whiteman et al. ^24. The imaging findings in cases of Toxoplasmosis ,Progressive multifocal leukoencephalopathy, CNS lymphoma ,HIV encephalopathy and fungal infections in our study were in concordance with previous studies done by Miguel J et al., Enting et al. ²⁵, Mark et al. ^26, Johnson et al. ^{27 ,}keerati hongsakul et al.²⁸ and M.Judith Donovan ²² Out of 60 patients, 6 % ( 10/60) showed meningitis. All the cases of meningitis were associated with CNS tuberculosis. We did not come across aseptic meningitis or meningitis due to other opportunistic infections. In our study 11 (18.3 %) patients had imaging feature suggestive of Infarct. Five patients had infarct secondary to tuberculosis infection.In another five patients etiology of infarct was not clearly established but these patients had no other risk factors such as hypertension, diabetes, hyperlipidemia or smoking. In this particular group in absence of obvious etiological factors and after ruling out other predisposing factors to CV stroke, presumed diagnosis of HIV Vasculopathy was considered. However Possibility of infarcts secondary to other infection like CMV, varicella-zoster virus, previous sub clinical CNS infection or fungal infection were not ruled out. The etiology of vasculopathy in HIV-infected individuals has been widely debated, and is probably multifactorial. For practical purposes HIV vasculopathy may be classified as HIV-related vasculitis. Single case with subacute infarct showed mild irregularity of ipsilateral MCA on MR angiography. On deeper probe into the history,the patient gave history of chronic smoking and hypertension. Our study is comparable to study done by M.D. Connor et al. ²⁹ , Brent Tipping et al. ³⁰ and Alaka Deshpande et al. ³¹.

SUMMARY AND CONCLUSION

Tuberculosis is still the most common CNS pathology encountered in HIV/AIDS in India while there is rising trend in the cases of HIV induced primary neurological illness.Imaging findings of different brain pathologies may overlap but certain imaging characteristics and location of the lesions may favour a particular diagnosis. Nonetheless correlation with clinical history and other laboratory parameters are instrumental along with imaging. MRI is an excellent means of detection and characterization of brain lesions in Acquired Immunodeficiency Syndrome (AIDS) and should be considered as one of the first line investigations in a seropositive patient with neurological complains, in absence of any contraindication.

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