Sequential carotid Doppler study in acute stroke and its clinical correlation: A prospective study.

Objectives: Resistive index (RI) and pulsatility index (PI) assessed on carotid Doppler assess the hemodynamic status of cranial vasculature. They are related to the severity of stroke and help determine the overall outcome. This study was done to compare the hospital stay and stroke severity with RI and PI of both internal carotid arteries. Materials and Methods: Patients >18 years of age presenting within 48 h of anterior circulation stroke (either ischemic or hemorrhagic) were included. They were divided into two groups based on their length of stay (LOS). They were assessed clinically on days 1, 3, and 5, and underwent a carotid Doppler study on the same days. The Doppler parameters were correlated with the LOS and stroke severity for possible associations. Results: One hundred and one patients were included. Forty-seven patients had a favorable outcome based on LOS. In this group, significant decrease in RI and PI scores was seen from days 1 to 3. In patients with unfavorable outcome, there was a significant increase in PI on days 1-3 and days 1-5. The National Institutes of Health Stroke Scale decreased significantly from days 1 to 5 in favorable group. Conclusion: For those with an unfavorable outcome and prolonged LOS, PI continues to increase suggesting a failure of autoregulation. Carotid Doppler can be a simple bedside tool to predict outcome in patients with acute stroke.

1H NMR Using Metabolic Study in Body Fluids for Diagnosis of Cryptococcal Meningitis in Adults.

Background: Cryptococcal meningitis is considered to affect HIV patients and those with impaired immune systems. Early identification and treatment are the keys to decreasing morbidity and mortality related to CM. Using 1H NMR spectroscopy, a prospective case-control study will assess the metabolic profile of adults' serum, urine, and CSF. Methodology: The present multicentric study was conducted at Lucknow. The study included 150 participants, out of which there were 31 cryptococcal meningitis cases, 34 positive meningitis controls, and the rest, 85, were disease controls. Result: The discriminant function analysis (DFA) of the three biofluids was used to find significant metabolites between the cases and the control group collectively. A group categorization between control group and the cases in serum, urine, and CSF samples was also made possible by the NMR spectral bin-based orthogonal signal correction and principal component analysis score plots of important metabolites produced from DFA. The cases group had a higher proportion of patients with higher CSF protein levels than the positive control group (BM and TM). Acetone was found among urine samples in both control samples, i.e., positive and negative. Conclusion: This is the first study to explore biomarkers in serum, urine, and CSF in addition to radiological features and clinical symptoms. Hence, a quick, non-invasive prognosis and diagnosis of cryptococcal meningitis in adults can be made using clinical and microbiological investigation, as well as metabolomic analysis of urine samples. This study shows that urine can be used as a biofluid to differentiate between Cryptococcus meningitis in adults. However, when compared to the negative control, our sample size was significantly smaller, necessitating further confirmation on a larger sample size.

Autonomic Function Tests, Heart Rate Variability, and Electrophysiological Evaluation in Patients With a Primary Episodic Headache: An Observational Study.

PURPOSE: Cranial autonomic symptoms are typically associated with the trigeminal autonomic cephalalgias and also present in substantial cases of migraine. Autonomic nervous system dysfunctions are also been reported in headache disorders and postulated to promote headache attacks. This study was aimed to evaluate the parasympathetic and sympathetic autonomic functions tests in patients with a episodic primary headache and to investigate, if any, electrophysiological abnormalities in the blink reflex test and sympathetic skin response test in these patients. METHODS: In this cross-sectional study, a total of 100 patients, 50 patients each of migraine and tension-type headache attending the neurology OPD and fulfilling the diagnostic criteria of headache disorders were enrolled. Autonomic functions tests were performed in the Department of Physiology, whereas electrophysiological tests were powered by the Editorial Manager and ProduXion Manager from Aries Systems Corporation performed in the Department of Neurology. RESULTS: Significant association ( P < 0.05) was observed in "blood pressure response to sustained handgrip" (sympathetic activity) and "heart rate response to Valsalva maneuver" (parasympathetic activity) among patients with migraine. Although the mean sympathetic skin response latency of patients with migraine was within the normal range, it was significantly prolonged in comparison with the control group. "Blood pressure response to sustained handgrip" and "heart rate variability" were found to be significantly ( P < 0.05) different in patients with a tension-type headache. The blink reflex test was observed to be normal in all patients with a headache. Patients with migraine showed a significant dysautonomia in category three of the Ewing battery for autonomic functional disability. CONCLUSIONS: Autonomic functional abnormality, both sympathetic and parasympathetic, does exist in patients with a primary episodic headache.

Cranial Autonomic Symptoms in Migraine: An Observational Study.

Objective: Our aim was to observe frequency of cranial autonomic symptoms (CAS) in migraineurs (primary) and its relation with laterality of headache or other factors, if any. Background: Migraine episodes have headaches with or without aura, and sometimes associated with systemic autonomic nervous system symptoms. Primarily presence of cranial autonomic symptoms suggests diagnosis of TACs. But many studies reported cranial autonomic symptoms (CAS) ranging from 26% to 80% in migraine patients. Material and Methods: Consecutive patients of migraine attending our headache clinic were included in our study. Presence of CAS was recorded with respect to ocular, nasal, facial and aural symptoms along with headache characteristics and laterality information. Detailed clinical examination was performed. We used ICHD 3 (beta version) criteria. Results: Our study cohort comprised of 200 patients having mean (± SD) age 31.12 (± 10.67) years. There were 157 (78.5%), females. Out of 200 patients, 148 (74%) were having at least one CAS, of which 70% were having 2 or more CAS. Frequency of CAS was lacrimation (45.5%), conjunctival injection (34.5%), eyelid edema (34%), aural fullness (27.5%), facial sweating (25%), facial flushing (17.5%), nasal congestion (9%), rhinorrhea (5%) and ptosis (4%). Bilateral CAS was present in 129 (87%) and unilateral CAS in 19 (13%) (OR 35.31; 95% CI 9.19 to 135.7), (P < 0.0001). Sunlight as a trigger was present in all 148 (100%) patients. Conclusion: Our study showed that CASs in migraine is common and bilateral. Sunlight triggers headache in almost all CAS positive patients.

A Comparative Study of Regional Cerebral Blood Flow Asymmetry Index in Stroke Patients with or without Poststroke Depression Using 99m Tc-ECD Single-Photon Emission Computed Tomography.

Introduction Stroke is a major cause of death and disability around the globe. The development of depression following a stroke further increases the disability and impairs functional recovery. In recent decades, despite the advancement in structural and nuclear medicine imaging, the pathophysiologic basis of poststroke depression (PSD) is not well understood. Etiopathogenesis of PSD is multifactorial and afflictions of the frontal lobe, hippocampus, limbic region, and basal ganglia projections are implicated. Aim The aim of this study was to assess the regional cerebral blood flow (rCBF) using 99m Tc-ethyl cysteinate dimer single-photon emission computed tomography (SPECT) in patients with (PSD + ) or without PSD (PSD-). Materials and Methods To evaluate the hemispheric asymmetry, the percentage of asymmetry index (AI) was calculated for frontal, temporal, parietal, occipital, putamen, caudate, and thalamic regions of brain and compared between PSD+ and PSD-. The correlation between AIs over the different brain regions was also established in patients of PSD+ and PSD-. Our study cohort included 122 patients between 6 weeks and 1 year of stroke. Depression was present in 52 (42.6%) patients, assessed by hospital anxiety and depression scale (HADS) and general health questionnaire-28 items (GHQ-28) scale. The 28 patients with PSD+ and 18 PSD- gave consent for SPECT study. Results Our results are based on 46 patients who underwent SPECT study. In patients with PSD+ and PSD-, the HADS and GHQ-28 scores were 8.93 ± 2.77 vs. 3.94 ± 2.15 ( p = 0.001) and 40.96 ± 9.48 vs. 17.72 ± 5.38 ( p = 0.001), respectively. A significant difference in rCBF AI was found in the temporal lobe ( p = 0.03) between patients of PSD+ and PSD-. On logistic regression analysis, the odds ratio of rCBF AI for temporal lobe was 0.89 (95% confidence interval [CI]: 0.80-0.99; p = 0.04) and caudate nucleus was 0.85 (95% CI: 0.73-0.98; p = 0.03), which were statistically significant. PSD correlated with AI in temporal region ( r = -0.03; p = 0.03) but did not show significant correlation with other regions of brain between PSD+ and PSD-. Conclusion The presence of temporal lobe rCBF AI on SPECT is significantly associated with PSD. This may reflect the dysfunction of the limbic system and contribute to the occurrence of PSD.

Economic Burden of Cancer Treatment in a Region in South India: A Cross Sectional Analytical Study.

INTRODUCTION: The rising cost of cancer diagnosis and treatment has imposed a huge financial burden on the affected households. Understanding the nature of this burden will help us to formulate plans to avoid financial distress among the same. OBJECTIVE: The study aims to estimate the Out of Pocket Expenditure (OOPE) for the management of selected solid cancers among the Out-Patient Department (OPD) of Regional Cancer Centre in South India and to determine the proportion of families experiencing Catastrophic Health Expenditure (CHE) due to the same. METHODS: A hospital based cross sectional analytical study was undertaken in the authors' institute in South India. 474 solid cancer patients were interviewed in OPD of Radiation Oncology by a trained data collector. Sociodemographic variables, costs incurred under various headings and expenditure details of participants were obtained. Direct Medical and Direct Non-Medical costs were calculated, and its total was used as the OOPE. Costs were presented as mean with its standard error. Incidence of CHE was calculated using the 40% threshold on the Capacity to pay and was expressed as proportions with 95% confidence interval. Appropriate statistical tests were used to look for statistically significant differences in the study groups. RESULTS: The average OOP expenditure incurred by a cancer patient was INR 35,817 (USD 523.6) for male and INR 20,496 (USD 299.6) for female. Males had a significantly higher OOPE than females. The prevalence of catastrophic health expenditure (CHE) was 61.6% at the 40% CTP threshold. Patients who used insurance schemes had higher prevalence of CHE than those who did not use insurance schemes (65.5% vs 60.7%, p value 0.351). CONCLUSION: Cancer care provided through public institutions had a low direct medical cost, but the indirect cost seemed to be extremely high. Public based financial assistance is the need of the hour to help the cancer affected families.

Clinical value of perilesional perfusion deficit measured by Technetium-99m-ECD single-photon emission computed tomography in hypertensive intracerebral hemorrhage.

Pathological and experimental studies indicate the existence of a "penumbra" of progressive tissue damage and edema in regions immediately surrounding a hematoma in patients of intracerebral hemorrhage (ICH). This zone of oligemia surrounding ICH has a potential for perfusion recovery. Improved understanding of the pathophysiology of perilesional blood flow changes and brain injury after ICH may result in improved treatment strategies. The aim was to study perilesional blood flow changes in ICH by perfusion deficit (PD) measured by single-photon emission computed tomography (SPECT) and to correlate it with the severity of ICH and outcome. Forty-four patients of computed tomography (CT) documented nonlobar deep ICH suggestive of hypertensive hematoma of <7 days duration were subjected to 99mTc-ethylene diacetate SPECT scans of the brain. Patients with significant midline shift (0.5 cm) or global blood flow reduction were excluded from the analysis. SPECT scan of the brain was analyzed by segmental analysis, a semi-quantitative method of cerebral blood flow. A difference of radiotracer uptake of >10% between the region of interest of ICH cases and the ratio between the two ROI below 0.9 was taken as a significant PD. A correlation of PD was analyzed with that of various parameters such as the severity of stroke, duration from onset of ictus, and imaging including CT scan of the brain and SPECT scan. A statistically significant difference in the percentage of radiotracer uptake on comparison of ipsilateral and contralateral to ICH (P < 0.001) was observed, suggesting a significant hypoperfusion in the perilesional area in patients with ICH. A statistically significant correlation was noted between the severity of stroke and PD indicated by various parameters such as the National Institutes of Health Stroke Scale (NIHSS) score at admission (r = 0.328, P = 0.016), Glasgow Coma Scale (GCS) score at admission (r = -0.388, P = 0.005), and ICH score at admission (r = 0.314, P = 0.020). This study demonstrated more severe hypoperfusion in clinically severe ICH which is a possible explanation of poor outcomes in severe ICH cases. We observed hypoperfusion on SPECT study in 25 of 34 (73.5%) patients with subacute ICH and 5 of 10 patients (50%) with acute ICH. The mean time from the onset of ictus to SPECT scan done was 5.04 ± 1.75 days with a range of 1-7 days, suggesting the persistence of hypoperfusion in subacute stages too. This finding may be of clinical importance for identifying the salvageable area surrounding ICH for any possible intervention in future to improve the outcome. This study demonstrates that perilesional PD occurs in acute and subacute cases of ICH. This hypoperfusion is possibly time related and appears to be more severe in patients having major ICH with poor clinical and imaging parameters. This area of hypoperfusion or ischemic penumbra is a potential site for perfusion recovery to improve clinical outcomes and to reduce long-term neurological deficits.

A 2 DS 2 Score to Predict the Risk of Stroke-Associated Pneumonia in Acute Stroke: An Indian Perspective.

Background Stroke-associated pneumonia (SAP) is an important cause of poststroke morbidity and mortality. Several clinical risk scores predict the risk of SAP. In this study, we used the A 2 DS 2 score (age, atrial fibrillation, dysphagia, sex, and stroke severity) to assess the risk of SAP in patients admitted with acute stroke. Methods A high (5-10) and a low (0-4) A 2 DS 2 score was assigned to patients with acute stroke admitted to the neurology ward. Univariate binary logistic regression analysis was performed to find the strength of association of SAP and A 2 DS 2 score. Results There were 250 patients with acute stroke of which 46 developed SAP. Forty-four patients developed SAP in high score as against 2 in low-score group (odds ratio [OR] = 0.03, 95% confidence interval [CI] = 0.01-0.15, p = 0.0001). A 2 DS 2 score >5 had sensitivity of 82.6% and specificity of 65.1% to predict SAP. The mean A 2 DS 2 score in patients with pneumonia was 7.02 ± 1.40 compared to 4.75 ± 1.92 in patients without pneumonia ( p = 0.0001). Conclusions A 2 DS 2 score has a high sensitivity of 82% in predicting the risk of SAP and is a useful tool to monitor patients after acute stroke. A 2 DS 2 score can help in timely detection and prevention of SAP and reduction in caregiver's burden.

Mandating nerve biopsy: A step towards personalizing therapy in pure neuritic leprosy.

Pure neuritic leprosy (PNL) accounts for 5% to 10% of leprosy patients who usually present with asymmetrical neuropathy in the absence of lepra bacilli on slit-skin smears. However, nerve biopsies in PNL lack appropriate categorization in current immunologic terms. We aimed to classify nerve biopsies according to the immune spectrum of leprosy and assess the role of histologic classification of nerve biopsies in treating PNL. Patients from two tertiary care referral centres were enrolled in this incident case study. Patients presenting with mononeuropathy and multiple mononeuropathies presumably with leprosy, without skin lesions, underwent nerve biopsy and slit-skin smear examination. Amongst 78 patients with mononeuropathy, 38 were diagnosed with leprosy on nerve biopsy. Leprosy was classified as tuberculoid in 16, lepromatous in 5 and borderline in 17 patients. Lepra bacilli were present in 15 biopsies. On comparing histologic subtypes with number of nerves involved clinically, a significant number of cases with single nerve involvement showed multibacillary (BB, BL or LL) histology and vice versa. Nerve biopsy helps in diagnosing patients presenting with PNL and aids in classifying it to customize the treatment for best results. Current treatment recommendations for PNL from WHO and National Leprosy Eradication Program are based on clinical assessment only, which are likely to result in inconsistent treatment and possibly relapse in cases where histomorphology shows disparity. Inclusion of nerve biopsy to guide therapy in patients with PNL is suggested.

Evaluation of polymerase chain reaction in nerve biopsy specimens of patients with Hansen's disease.

BACKGROUND: Pure neuritic variety of leprosy (PNL) presents as peripheral neuropathy with absent skin lesions and negative skin smears. Diagnosing PNL is an uphill task as most of these patients have nonspecific changes on nerve biopsy. In such circumstances, additional molecular diagnostic tools like polymerase chain reaction (PCR) has proven to be useful in diagnosing leprosy. The present study was planned to evaluate the role of PCR in nerve biopsy specimens of patients with PNL. METHODS: Patients attending the neuromuscular clinic from January 2013 to June 2014 with mononeuropathy multiplex underwent detailed diagnostic evaluation to ascertain the cause of neuropathy. Patients where this evaluation failed to establish an etiology underwent a nerve biopsy. RESULTS: Nerve biopsy was done in 52 patients, of which 35 were diagnosed as pure neuritic leprosy. Definite leprosy with positive wade fite staining for lepra bacilli was seen in 13 patients and 22 biopsies revealed a probable leprosy without lepra bacilli being identified. PCR for M. leprae was positive in 22 patients (62%). 12 of the 13 cases with definite leprosy on histopathology were PCR positive while in the AFB negative group, PCR was positive in 10 cases. PCR had a sensitivity of 92.3%, specificity of 54.5%. The positive and negative predictive value of PCR was 54.5% and 92.3% respectively. CONCLUSIONS: PCR helps in diagnosing PNL in doubtful cases. A positive PCR increases the sensitivity of detection of M. leprae especially in cases of probable PNL group where AFB cannot be demonstrated on histopathology.

Dopa-responsive Dystonia in a Child Misdiagnosed as Cerebral Palsy.

Dopa-responsive dystonia also known as "Segawa's syndrome" was first described in 1976. The dystonia typically shows diurnal variations and is more marked toward the end of the day and improves in sleep. This entity is often misdiagnosed in the clinical setting, mostly due to the lack of awareness, and these patients are exposed to various treatment regimens and nonpharmacological measures. We present a boy being treated as dystonic cerebral palsy who showed significant improvement in dystonic symptoms with L-dopa therapy.

Stroke Associated With Varicella Zoster Vasculopathy: A Clinicoradiological Profile of 3 Patients.

INTRODUCTION: Varicella zoster (VZ) vasculopathy is a rare but well recognized cause of stroke. In the absence of zoster rash and infection in remote past, the disease can pose diagnostic challenge. We report 3 cases of anterior circulation stroke occurring in close temporal relation to VZ. Their clinical, radiologic, and angiographic features are discussed. CASE REPORT: Of the 3 patients, 2 had stroke within a span of 4 to 6 weeks of herpes zoster ophthalmicus while the third patient had zoster of cervical dermatome. Magnetic resonance imaging revealed acute subcortical infarcts in 2, while 1 patient showed acute on chronic infarct in left middle cerebral artery territory. The magnetic resonance angiography was abnormal in 2 patients while it was normal in third. All the patients were treated with acyclovir and antiplatelets with good recovery in 2. CONCLUSIONS: VZ associated vasculopathy may have diverse clinical profile and neuroimaging features. It should be considered as an important and treatable cause of stroke in appropriate clinical settings.

Analysis of Clinical and Metabolic Profile of Acute Neuromuscular Weakness Related to Hypokalemia.

OBJECTIVE: Acute neuromuscular weakness related to hypokalemia is a readily treatable disorder associated with diverse aetiologies. In this study we aim to report clinical pattern and biochemical features to identify the different aetiologies of the hypokalemic neuromuscular weakness. METHODS: Retrospective reviews of the medical record were analysed. Evaluation included demography, clinical features, investigations performed to ascertain the aetiologies. All the patients were categorised in to 3 groups; Idiopathic hypokalemic paralysis (IHP), dengue associated hypokalemic paralysis (DHP) and secondary group (SG) which included renal tubular acidosis (RTA- 1 and 2), thyrotoxic periodic paralysis (TPP) and Gitelman's syndrome (GS). RESULTS: Forty patients were analysed and the mean age was 31.78 (range, 14-60) years and 35 (87.5%) were male.The underlying aetiologies comprised of IHP in 20, DHP in 12, RTA-2 in 4, RTA-1 in 2, TPP, GS in one each. Weakness on Medical Research Council (MRC) grade was 2.6±1.19 (range 0-4). Comparison of various clinical and laboratory parameters revealed that more patient in IHP and SG had recurrent attack (p=0.001). DHP group had low platelet (p=0.001), high creatine phosphokinase (CPK) (p=0.01) and serum glutamic oxaloacetic transaminase (SGOT) (p=0.008). SG had significantly lower serum potassium (p=0.04) and more time to improve (p=0.02). Recovery time correlated negatively with serum potassium (r=-0.44, p=0.004) and grade of weakness (r= 0.42,p=0.007). CONCLUSION: In half of the patients, secondary causes were identified. After IHP, the DHP emerged as second common cause in post monsoon season. SG had significantly lower serum potassium, recurrent attack and more time to improve.

Acute Encephalitis Syndrome in Adults and Its Correlation with Cytokine Levels in the Serum and Cerebrospinal Fluid.

Acute encephalitis syndrome (AES) is a major health problem in developing countries including India. Neuronal injury in encephalitis is attributed to direct toxicity from pathogens and proinflammatory cytokines. In this study, we assessed cytokine levels in serum and cerebrospinal fluid (CSF), and their correlation with clinical symptoms. In our study, patients with AES for a duration of less than 2 weeks underwent brain imaging followed by CSF analysis for routine parameters and viral studies. We assessed interleukin (IL)-6, IL-10, and regulated on activation, normal T cell expressed and secreted (RANTES) levels in the serum samples of all patients and in 50 CSF samples and compared them with serum cytokine levels of 64 age- and sex-matched controls. Of the 87 AES patients, 13 had Japanese encephalitis (JE). Serum IL-6, IL-10, and RANTES levels were significantly elevated in patients with AES compared with that in controls. Serum IL-10 levels were significantly reduced while RANTES levels were significantly elevated in patients who died. CSF IL-6 and IL-10 levels were significantly elevated in the non-JE group compared with that in JE patients. RANTES levels in the CSF were high in patients who had no seizures. IL-10 exerts its anti-inflammatory effect by modulating the innate and adaptive immune response, thus limiting the production of pro-inflammatory cytokines. Higher IL-10 levels were found to be protective in patients with acute encephalitis.

Nerve biopsy in Indian patients with mononeuropathy multiplex of undetermined etiology.

INTRODUCTION: A diagnosis of mononeuropathy multiplex (MM) requires detailed evaluation to determine etiology. We performed nerve biopsy on patients with MM in whom the etiology could not be established via other investigations. METHODS: Sixty-eight patients with MM seen between January 2013 and June 2014 underwent detailed diagnostic evaluation. Those in whom the investigations failed to establish an etiology underwent nerve biopsy. RESULTS: A diagnosis of leprosy was confirmed in 14 patients and was highly probable in 17 others. Eleven patients had vasculitic neuropathy, and in 1 patient there were amyloid deposits on nerve biopsy. CONCLUSIONS: In 43 of 68 Indian patients (63%) with MM, nerve biopsy identified a definite (26 patients) or probable (17 patients) etiology. Nerve biopsy is a valuable investigation in MM that frequently results in a diagnosis of leprosy in India. Muscle Nerve, 2016 Muscle Nerve 55: 23-27, 2017.

Rapidly Resolving Weakness Related to Hypokalemia in Patients Infected With Dengue Virus.

OBJECTIVES: Dengue is a mosquito-borne disease caused by arbovirus and well known for its typical fever with thrombocytopenia syndrome. Acute hypokalemic quadriparesis is a rare presentation of dengue with uncertain pathogenesis. We aim to describe the clinical and biochemical characteristics of rapidly resolving weakness related to hypokalemia in patients infected with dengue virus. METHODS: A retrospective review of the records of patients with diagnosis of dengue-associated hypokalemic weakness was performed. Demography, clinical, biochemical characteristics, and outcome of the patients were recorded during acute phase of illness. RESULTS: Our study cohort comprised 12 patients and all were males from urban dwelling. The median age was 34.5 years (range, 18-50). Presentation was acute onset rapidly worsening pure motor quadriparesis preceded by short lasting febrile episode. Weakness ranged from 2/5 to 4/5 on Medical Research Council (MRC) scale with generalized hyporeflexia or areflexia. The baseline serum potassium was mean ± SD (2.7 ± 0.48 mmol/L). All patients showed elevation of liver transaminases and elevated creatine phosphokinase level. Weakness improved in 24-72 hours in all patients with correction of serum potassium. CONCLUSIONS: Dengue-associated acute hypokalemic paralysis is an underrecognized entity having favorable outcome. It should be suspected in patients presenting as acute pure motor quadriparesis after febrile illness in dengue endemic areas.

Subacute Sclerosing Panencephalitis in a Child with Human Immunodeficiency Virus Co-Infection.

Subacute sclerosing panencephalitis is a fatal infectious disease of childhood caused by persistence of the measles virus in the brain. The effect of human immunodeficiency virus (HIV) co-infection on subacute sclerosing panencephalitis remains elusive and rare. We report a child who developed subacute sclerosing panencephalitis following a short latency period and a rapidly progressive course with HIV co-infection.