Brain abscess and hereditary hemorrhagic telangiectasia

Neuroimaging Pearls from the MDS Congress Video Challenge. Part 1: Genetic Disorders

We selected several "imaging pearls" presented during the Movement Disorder Society (MDS) Video Challenge for this review. While the event, as implicated by its name, was video-centered, we would like to emphasize the important role of imaging in making the correct diagnosis. We divided this anthology into two parts: genetic and acquired disorders. Genetic cases described herein were organized by the inheritance pattern and the focus was put on the imaging findings and differential diagnoses. Despite the overlapping phenotypes, certain described disorders have pathognomonic MRI brain findings that would provide either the "spot" diagnosis or result in further investigations leading to the diagnosis. Despite this, the diagnosis is often challenging with a broad differential diagnosis, and hallmark findings may be present for only a limited time.

Thalamic abscess in a patient with hereditary hemorrhagic telangiectasia successfully treated with an empiric antibiotic regime: case report and review of the literature

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disease associated with neurological complications, including cerebral abscesses (CA). They tend to be unique, supratentorial and lobar. While the surgical intervention is a rule of thumb when treating and diagnosing the etiology of these lesions, this is not always possible due to dangerous or inaccessible locations. We report the case of a patient solely treated with empiric antibiotics without stereotaxic intervention and satisfactory results.

CASE PRESENTATION

We present the case of a 21-year-old patient with a right thalamic abscess due to HHT and pulmonary arteriovenous malformations, previously embolized, treated solely with antibiotics. At first, we contemplated the possibility of a stereotaxic biopsy, but the high-risk location and the fact that our patient received a previous full course of antibiotic treatment (in another center), made us discard this intervention because of the low diagnostic yield. We started an empiric antibiotic regime. We followed up very closely the clinical and radiological evaluation the next weeks, adjusting our antibiotic treatment when necessary. The results were favorable from both the radiological and clinical aspects and 6 months after the diagnosis the images show its almost complete disappearance.

CONCLUSION

Carefully tailored antibiotic-only regime and vigilance of its adverse effects and close radiological following is a good treatment approach when surgery is not an option.

Gender differences in hereditary hemorrhagic telangiectasia severity

Background

Gender differences in organ involvement and clinical severity have been poorly described in hereditary hemorrhagic telangiectasia (HHT). The aim of this study was to describe differences in the severity of HHT manifestations according to gender.

Methods

Severity was measured according to Epistaxis Severity Score (ESS), Simple Clinical Scoring Index for hepatic involvement, a general HHT-score, needing for invasive treatment (pulmonary or brain arteriovenous malformations -AVMs- embolization, liver transplantation or Young’s surgery) or the presence of adverse outcomes (severe anemia, emergency department -ED- or hospital admissions and mortality).

Results

One hundred forty-two (58.7%) women and 100 (41.3%) men were included with a mean age of 48.9 ± 16.6 and 49 ± 16.5 years, respectively. Women presented hepatic manifestations (7.1% vs 0%) and hepatic involvement (59.8% vs 47%), hepatic AVMs (28.2% vs 13%) and bile duct dilatation (4.9% vs 0%) at abdominal CT, and pulmonary AVMs at thoracic CT (35.2% vs 23%) more often than men. The Simple Clinical Scoring Index was higher in women (3.38 ± 1.2 vs 2.03 ± 1.2), and more men were considered at low risk of harboring clinically significant liver disease than women (61% vs 25.3%). These differences were mantained when considering HHT1 and HHT2 patients separetely. Duodenal telangiectasia were more frequent in men than women (21% vs 9.8%). Invasive treatments were more frequently needed in women (28.2% vs 16%) but men needed attention at the ED more often than women (48% vs 28.2%), with no differences in ESS, HHT-score, anemia hospital admissions or mortality.

Conclusions

HHT women showed more severe hepatic involvement than men, also among HHT1 and HHT2 patients. Women had higher prevalence of pulmonary AVMs and needed invasive procedures more frequently, while men needed attention at the ED more often. These data might help physicians to individualize HHT patients follow-up.

Novel mutation in ENG gene causing Hereditary Hemorrhagic Telangiectasia in a Peruvian family

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare disorder of vascular development. Common manifestations include epistaxis, telangiectasias and arteriovenous malformations (AVMs) in multiple organs. Most patients have deletions or missense mutations in the ENG or ACVRL1 gene respectively, significantly affecting endothelium homeostasis. We analyzed the ENG gene in five members of a Peruvian family affected by HHT. One novel mutation was found in exon four of the ENG gene c.408delA, at aminoacid residue 136. This mutation changes the subsequent reading frame producing an early stop at residue 162, preserving only one fourth of the normal protein of 658 aa. This mutation was found in the four affected members of family.

Benefits of Treating Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia: A Retrospective Analysis of 14 Patients

Background

Arteriovenous malformations (AVMs) are a cardinal feature of hereditary hemorrhagic telangiectasia (HHT). However, whether to treat brain AVMs in patients with HHT remains questionable because of the possible risks.

Methods

We performed a retrospective study of patients with HHT who had been treated for brain AVMs at our institution from January 1, 2003, to December 31, 2016. An institutional database was queried for the phrases “hereditary hemorrhagic telangiectasia” and “HHT,” and those patients who had been treated during the study period were identified. Data were extracted regarding presentation, AVM characteristics, treatment modality, and treatment outcomes.

Results

We identified 14 patients (10 males, 4 females) with HHT who had had AVMs (n = 27) from the institutional database. The mean age of the patients was 43 years (range, 2–64). Of the 27 brain AVMs, 13 were Spetzler-Martin grade I, 12 were grade II, and 2 were grade III; none were grade IV or V. Treatment was by microsurgery only (11 AVMs in 10 patients), embolization followed by microsurgery (2 AVMs in 2 patients), and radiosurgery only (12 AVMs in 2 patients). AVM obliteration was achieved in 100% of the patients. No new fixed neurologic deficits developed after treatment of unruptured HHT AVMs.

Conclusions

The risk of treatment of brain AVMs in patients with HHT is quite low for appropriately selected patients with treatment individualized to radiosurgery, microsurgery, or a combination of embolization and microsurgery.

Pulmonary Arteriovenous Malformations and Cerebral Abscess Recurrence in a Child With Hereditary Hemorrhagic Telangiectasia

BACKGROUND

A 17-year-old boy was referred to our center with a history of brain abscess (BA) recurring after 9 years. The patient reported 2 previous treatments for pulmonary arteriovenous malformations, sporadic nosebleeds, and familial history for epistaxis. Clinical investigations revealed arteriovenous malformations in lung, brain, and liver, as well as mucocutaneous telangiectases. A definite diagnosis of hereditary hemorrhagic telangiectasia was made based on clinical criteria and confirmed by genetic analysis. This is the first report of BA recurrence at the end of pediatric age.

CONCLUSIONS

The present case and the literature review of all cases of BA thus far reported highlight the need to raise the suspicion of a pulmonary arteriovenous malformations, both isolated and in the context of a possible hereditary hemorrhagic telangiectasia, for any case of BA of unexplained etiology, in children as well as in adults.

Cerebral vascular malformations in hereditary hemorrhagic telangiectasia

Object

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disorder characterized by mucocutaneous telangiectasias, frequent nosebleeds, and visceral arteriovenous malformations (AVMs). Few reports have outlined the prevalence of the various cerebral vascular malformations found in patients with HHT. The authors set out to define the prevalence of cerebral vascular malformations in a population of HHT patients who underwent imaging with 3-T imaging (MRI/MR angiography [MRA]) of the brain.

Methods

A retrospective review of prospectively collected data was carried out using a database of 372 HHT patients who were seen and examined at the Georgia Regents University HHT Center and screened with 3-T MRI/MRA. Data were tabulated for numbers and types of vascular malformations in this population.

Results

Arteriovenous malformations were identified in 7.7%, developmental venous anomalies in 4.3%, and cerebral aneurysms in 2.4% of HHT patients. The HHT AVMs tended to be supratentorial, small, and cortical in this series, findings consistent with other recent studies in the literature. An arteriovenous fistula, cavernous malformation, and capillary telangiectasia were identified in 0.5%, 1%, and 1.9% of HHT patients, respectively.

Conclusions

Few studies have investigated the prevalence of the various vascular malformations found in HHT patients screened with 3-T MRI/MRA of the brain. Hereditary hemorrhagic telangiectasia AVMs are more likely to be multiple and have a tendency toward small size and cortical location. As such, they are often treated using a single-modality therapy.

Immunological abnormalities associated with hereditary haemorrhagic telangiectasia

OBJECTIVE

Hereditary haemorrhagic telangiectasia (HHT) is a genetic disorder related to mutations in one of the coreceptors to the transforming growth factor-β superfamily (ALK1 or endoglin). Besides the obvious vascular symptoms (epistaxis and arteriovenous malformations), patients have an unexplained high risk of severe bacterial infections. The aim of the study was to assess the main immunological functions of patients with HHT using the standard biological tests for primary immunodeficiencies.

DESIGN, SETTING AND SUBJECTS

A prospective single-centre study of 42 consecutive adult patients with an established diagnosis of HHT was conducted at the National French HHT Reference Center (Lyon). Lymphocyte subpopulations and proliferation capacity, immunoglobulin levels and neutrophil and monocyte phagocytosis, oxidative burst and chemotaxis were assessed.

RESULTS

Innate immunity was not altered in patients with HHT. With regard to adaptive immunity, significant changes were seen in immunological parameters: primarily, a lymphopenia in patients with HHT compared with healthy control subjects affecting mean CD4 (642 cells μL(-1) vs. 832 cells μL(-1) , P < 0.001), CD8 (295 cells μL(-1) vs. 501 cells μL(-1) , P < 0.0001) and natural killer (NK) cells (169 cells μL(-1) vs. 221 cells μL(-1) , P < 0.01), associated with increased levels of immunoglobulins G and A. This lymphopenia mainly concerned naïve T cells. Proliferation capacities of lymphocytes were normal. Lymphopenic patients had a higher frequency of iron supplementation but no increase in infection rate. Lower levels of immunoglobulin M and a higher rate of pulmonary arteriovenous malformations were found amongst patients with a history of severe infection.

CONCLUSIONS

Patients with HHT exhibit immunological abnormalities including T CD4, T CD8 and NK cell lymphopenia and increased levels of immunoglobulins G and A. The observed low level of immunoglobulin M requires further investigation to determine whether it is a specific risk factor for infection in HHT.

Brain abscess caused by Enterococcus faecalis following a dental procedure in a patient with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a disease characterized by arteriovenous malformations (AVMs). Brain abscess is a complication of HHT with AVMs. Literature provides evidence that Enterococcus faecalis can cause endodontic infections. We present the case of an HHT patient who developed brain abscess due to E. faecalis after a dental procedure.

Cerebral abscesses in hereditary haemorrhagic telangiectasia: a clinical and microbiological evaluation

OBJECTIVES

Hereditary haemorrhagic telangiectasia (HHT) is a rare autosomal dominant disorder that can lead to neurological manifestations including strokes and cerebral abscesses. Our objectives were to describe clinical, radiological, bacteriological, and outcome characteristics of patients with cerebral abscess and HHT, and to concurrently compare this group with a control group with cerebral abscess, but without HHT.

PATIENTS AND METHODS

Patients with HHT and cerebral abscess in 5 French medical centers were included. Their clinical, radiological, biological data and prognosis were compared to the data of unselected patients with cerebral abscesses but without HHT included during the same period of time.

RESULTS

Twenty-six patients (13 men and 13 women; 44.7±17.2; range 12-79 years), with HHT and cerebral abscess were included. A pulmonary arteriovenous malformation (AVM) was present in all cases. Cerebral abscesses were solitary, supratentorial, and mostly lobar. In all cases, pathogens were anaerobic or facultative anaerobic germs (particularly streptococcus). No death was observed, but various sequels were present in up to two-thirds of the patients. We observed a recurrence of the cerebral abscess in 4 patients with a mean delay of 81 months. In comparison with the control group, cerebral abscesses were generally of later recurrence and significantly more often unique and less often due to staphylococcus.

CONCLUSION

HHT cerebral abscesses are particularly linked to pulmonary arteriovenous malformations and anaerobic germs. Their clinical, radiological and bacteriological characteristics are quite different than in a control group with more solitary brain localizations, no staphylococcus infection and a significantly longer interval to recurrence.

Toll-like receptors in brain abscess

Brain abscesses arise from a localized parenchymal infection, typically elicited by pyogenic bacteria such as Staphylococcus aureus. Despite improvements in detection and treatment strategies, brain abscesses continue to occur, with an increased prevalence in developing countries and immune-compromised patients. Adding to the seriousness of these infections is the recent emergence of antibiotic-resistant strains of bacteria, which are becoming more commonly associated with brain abscesses. Recent studies using a mouse experimental brain abscess model have revealed a complex role for Toll-like receptors (TLRs) in disease pathogenesis. Interestingly, TLR2 has limited impact on the innate immune response during the acute stage of brain abscess formation induced by S. aureus but influences adaptive immunity. In contrast, mice deficient in MyD88, a central adapter molecule for the majority of TLRs in addition to the IL-1R and IL-18R, demonstrate severe defects in innate immunity coupled with exaggerated tissue destruction. It is envisioned that understanding the roles for TLRs in both resident CNS glia as well as infiltrating immune cells will provide insights into how the immune response to bacterial infection can be tailored to achieve effective pathogen destruction without inducing excessive bystander damage of surrounding noninfected brain parenchyma. A discussion of recent findings in this field is presented along with outstanding questions and the concept of a pathogen-necrosis-autoantigen triad for the amplification of TLR signaling is introduced.