RESUMEN
Acromegaly due to ectopic secretion of growth hormone-releasing hormone (GHRH) is a rare disorder. The signs and symptoms of ectopic acromegaly are indistinguishable from acromegaly due to a somatotroph adenoma. A 35-year-old female presented with secondary amenorrhea for 10 years, intermittent headache, and reduced vision in both eyes for 4 years, which worsened over 4 months before presentation. Additionally, she was diagnosed with uncontrolled diabetes mellitus. On examination, she had coarse facial features, a fleshy nose, and acral enlargement. She had diminished visual acuity (left>right) and bitemporal hemianopia on perimetry. Biochemical investigations revealed elevated IGF-1 [588 ng/ml, reference range (RR) 100-242], markedly elevated basal growth hormone (>80 ng/ml; RR, 0.12-9.88), and hyperprolactinemia in the tumoral range (832 ng/ml; RR, 5-25). MRI sella demonstrated a 22×30×34mm sellar-suprasellar mass with T2 hypointensity. Chest imaging revealed a 75×87×106mm left lung mass, which was found to be a well-differentiated neuroendocrine tumor (NET) on biopsy. Plasma GHRH levels were elevated [38,088 ng/l; RR, <250-300], and a diagnosis of ectopic acromegaly secondary to lung neuroendocrine tumor was considered. During workup, the patient developed in-hospital pituitary apoplexy, which improved with medical management. After a left pneumonectomy, her clinical features of acromegaly improved, her diabetes underwent remission, and there was a marked reduction in plasma GHRH and pituitary size. Histopathology was suggestive of a neuroendocrine tumor, with immunohistochemistry positive for GHRH and negative for prolactin. Her final diagnosis was ectopic acromegaly due to GHRH secreting a lung NET with pituitary somatotroph and lactotroph pituitary hyperplasia and apoplexy in the hyperplastic pituitary.
Asunto(s)
Acromegalia , Hiperplasia , Hiperprolactinemia , Apoplejia Hipofisaria , Humanos , Femenino , Adulto , Acromegalia/complicaciones , Hiperprolactinemia/complicaciones , Hiperprolactinemia/etiología , Hiperplasia/complicaciones , Hiperplasia/patología , Apoplejia Hipofisaria/complicaciones , Hipófisis/patología , Hipófisis/diagnóstico por imagen , Hipófisis/metabolismo , Hormona Liberadora de Hormona del Crecimiento/metabolismo , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/patologíaRESUMEN
INTRODUCTION: Pituitary apoplexy (PA) is a rare clinical syndrome due to acute/subacute pituitary hemorrhage and/or infarction; data on PA in functioning pituitary adenoma (FPA) is scarce. METHODS: A retrospective record-review of details of PA in non-functioning (NFPA) and FPA managed at tertiary endocrine center. RESULTS: 93 patients [56 males; 33.3% FPA: 5 acromegaly, 14 prolactinoma, and 12 Cushing's Disease (CD)] diagnosed with PA were included. Median age was 40 years, with younger age of presentation in FPA. Type A (acute) [49.5%] and headache (78.5%) were the commonest presentations, with PA being the initial manifestation in 98.4% of NFPA. Median (range) Pituitary Apoplexy Score (PAS) was 2 (0-8). Median tumor diameter was 2.5 cm, with larger tumors in FPA (3.2 cm vs. 2.3 cm). 29 (46.7%) NFPA-PA and 14 (45.2%) FPA-PA patients [71% prolactinoma, 33% in CD, and none in acromegaly] were conservatively managed. In the NFPA cohort, those managed surgically had significantly higher PAS (4 vs. 1) and larger tumor size (2.6 vs. 1.8 cm); however, both arms had comparable recovery of neuro-visual, radiological, and hormonal outcomes. In FPA cohort, CD and acromegaly required definitive treatment, whereas prolactinomas were effectively managed (clinical and biochemical recovery) with oral cabergoline and glucocorticoids. Matching PAS cohorts (to overcome allocation bias for management approach) in macroadenomas (excluding prolactinoma) showed comparable neuro-deficit and hormonal recovery between surgical and conservative approaches. CONCLUSION: PA in FPA has distinct features and management issues. Carefully selected patients (PAS guided) in NFPA with PA for conservative management have comparable outcomes to surgery.
Asunto(s)
Apoplejia Hipofisaria , Neoplasias Hipofisarias , Prolactinoma , Humanos , Apoplejia Hipofisaria/patología , Masculino , Femenino , Adulto , Neoplasias Hipofisarias/patología , Persona de Mediana Edad , Estudios Retrospectivos , Prolactinoma/patología , Prolactinoma/complicaciones , Anciano , Adenoma/patología , Adenoma/complicaciones , Adulto Joven , Cabergolina/uso terapéutico , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/patologíaAsunto(s)
Apoplejia Hipofisaria , Humanos , Apoplejia Hipofisaria/diagnóstico , Apoplejia Hipofisaria/complicaciones , Imagen por Resonancia Magnética , Neoplasias Hipofisarias/diagnóstico por imagen , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/diagnóstico , Masculino , Femenino , Persona de Mediana EdadRESUMEN
INTRODUCTION: Hypoglycemia is a common occurrence in diabetic patients. But unlike non diabetic patients, its causes are frequently related to drugs they are receiving to control blood glucose. But this may not always be the case. Here we report a type 2 diabetic patient with severe hypoglycemia owing to acute hypopituitarism secondary to pituitary apoplexy. CASE PRESENTATION: A 45 year old male diabetic patient from Ethiopia taking 2 mg of oral glimepiride daily who presented with change in mentation of 30 minutes and blood glucose recording of 38 mg/dl upon arrival to the emergency room. Brain magnetic resonance imaging showed pituitary macroadenoma with hemorrhage suggestive of pituitary apoplexy. Blood work up showed low adrenocorticotropic hormone, cortisol, and serum sodium levels. Subsequently transsphenoidal hypophysectomy was done. CONCLUSION: The occurrence of hypoglycemia in a diabetic patient taking sulphonylurea monotherapy is common. But when it is severe enough to cause altered mentation, patients should be approached differently. In the presence of clinical clues suggesting cortisol deficiency, hypopituitarism can be a possible cause.
Asunto(s)
Diabetes Mellitus Tipo 2 , Hipoglucemia , Hipoglucemiantes , Hipopituitarismo , Apoplejia Hipofisaria , Compuestos de Sulfonilurea , Humanos , Masculino , Apoplejia Hipofisaria/complicaciones , Apoplejia Hipofisaria/diagnóstico por imagen , Hipoglucemia/etiología , Persona de Mediana Edad , Diabetes Mellitus Tipo 2/complicaciones , Compuestos de Sulfonilurea/uso terapéutico , Compuestos de Sulfonilurea/efectos adversos , Hipopituitarismo/complicaciones , Hipopituitarismo/diagnóstico , Hipoglucemiantes/uso terapéutico , Imagen por Resonancia Magnética , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/cirugía , Neoplasias Hipofisarias/diagnóstico por imagen , Hipofisectomía , Adenoma/complicaciones , Adenoma/cirugía , Adenoma/diagnóstico por imagen , Hidrocortisona/uso terapéutico , Hidrocortisona/sangre , Hidrocortisona/administración & dosificación , Glucemia/análisisRESUMEN
BACKGROUND: Pituitary apoplexy (PA) is characterized by acute hemorrhage or infarction of the pituitary gland. Management can be either conservative or surgical. Evidence favoring either is still limited to observational studies. This meta-analysis evaluates the effectiveness of both approaches on patient outcomes. METHODS: A systematic search was performed until February 2024. We included cohort studies of patients with PA. Patients were divided into 2 groups: a conservative management group and a surgery group, including early and late surgery. Outcomes of interest were assessed categorically using risk ratio (RR) and Mantel-Haenszel's random effects model. RESULTS: Of the 273 published articles, 15 cohort studies comprising 908 patients were included. There was no statistically significant difference between groups in recovery of ophthalmoplegia (RR=1.09, confidence interval [CI]=1.00-1.18, P=0.05), visual field (RR=1.09, CI=0.91-1.3, P=0.35), visual acuity (RR=1.05, CI=0.87-1.26, P=0.61), hypopituitarism (RR=1.37, CI=0.81-2.32, P=0.25), and tumor recurrence (RR=0.74, CI=0.34-1.61, P=0.45). This was similar for conservative management versus early surgery in recovery of visual field (RR=0.92, CI=0.62-1.37, P=0.68), visual acuity (RR=1.01, CI=0.81-1.26, P=0.93), and ophthalmoplegia (RR=0.92, CI=0.53-1.61, P=0.77). CONCLUSIONS: Both interventions provide comparable outcomes. These findings, though, are drawn from observational studies, and more severe cases typically undergo surgery. Larger studies are necessary to provide conclusive evidence.
Asunto(s)
Apoplejia Hipofisaria , Humanos , Tratamiento Conservador/métodos , Hipopituitarismo/etiología , Procedimientos Neuroquirúrgicos/métodos , Oftalmoplejía/etiología , Apoplejia Hipofisaria/complicaciones , Apoplejia Hipofisaria/cirugía , Apoplejia Hipofisaria/terapia , Resultado del TratamientoRESUMEN
INTRODUCTION: Pituitary apoplexy (PA) in Cushing's disease (CD) is rare with data limited to case reports/series. METHODS: We retrospectively reviewed case records of PA in CD managed at our center from 1987 to 2023 and performed a systematic literature review. RESULTS: We identified 58 patients (44 females), including twelve from our center (12/315 CD, yielding a PA prevalence in CD of 3.8%) and forty six from systematic review. The median age at PA diagnosis was 35 years. The most common presentation was type A (79.3%) and symptom was headache (89.6%), with a median Pituitary Apoplexy Score (PAS) of 2. Median cortisol and ACTH levels were 24.9 µg/dl and 94.1 pg/ml, respectively. Apoplexy was the first manifestation of underlying CD in 55.2% of cases, with 31.1% (14/45) presenting with hypocortisolemia (serum cortisol ≤ 5.0 µg/dl), underscoring the importance of recognizing clinical signs/symptoms of hypercortisolism. The median largest tumor dimension was 1.7 cm (53/58 were macroadenomas). PA was managed surgically in 57.8% of cases, with the remainder conservatively managed. All five PA cases in CD with microadenoma achieved remission through conservative management, though two later relapsed. Among treatment-naïve CD patients with macroadenoma, PA-related neuro-deficit improvement was comparable between surgical and conservative groups. However, a greater proportion of surgically managed patients remained in remission longer (70% vs. 38.5%; p = 0.07), for an average of 31 vs. 10.5 months. CONCLUSION: PA in CD is more commonly associated with macroadenomas, may present with hypocortisolemia, and surgical treatment tends towards higher and longer-lasting remission rates.
Asunto(s)
Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT) , Apoplejia Hipofisaria , Humanos , Apoplejia Hipofisaria/epidemiología , Apoplejia Hipofisaria/patología , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/diagnóstico , Femenino , Estudios Retrospectivos , Adulto , Masculino , Persona de Mediana Edad , Hidrocortisona/sangre , Hormona Adrenocorticotrópica/sangre , Hormona Adrenocorticotrópica/metabolismoRESUMEN
PURPOSE: Pregnancy is a known risk factor for Pituitary Apoplexy (PA) but there is a lack of consistency in the literature regarding non-gestational risk factors responsible for PA. METHODS: We did a systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify the non-gestational risk factors associated with the development of PA in adult patients with pituitary adenoma. Also, we discuss here a case of an elderly female with pituitary macroadenoma who was initially planned for pituitary resection electively but underwent emergency surgery after she developed PA. RESULTS: As per screening and eligibility criteria, seven studies with 4937 study participants were included in this systematic review out of which 490 (9.92%) patients had PA, including asymptomatic subclinical PA (SPA) and symptomatic clinical PA (CPA). The macroadenomas and negative staining of the tumor were found to be a significant risk factor consistently in multivariate analysis in three and two retrospective studies, respectively. However, the results were varied for any significant difference in the risk factors for apoplexy between SPA and CPA. Similarly, there was no consistency among the studies for risk factors significantly responsible for CPA or PA compared to controls. CONCLUSION: No single non-gestational risk factor is solely responsible for the development of PA in a pituitary adenoma compared to the control population. Tumor size (macroadenoma) and the non-functioning status of the adenoma are the only significant factors contributing independently toward an apoplectic event in most patients. Such patients can be prioritized for early pituitary tumor resection.
Asunto(s)
Apoplejia Hipofisaria , Neoplasias Hipofisarias , Humanos , Apoplejia Hipofisaria/patología , Factores de Riesgo , Femenino , Neoplasias Hipofisarias/patología , Neoplasias Hipofisarias/cirugía , Adenoma/patología , Adenoma/cirugía , Adenoma/epidemiología , EmbarazoRESUMEN
PURPOSE: To identify clinical and radiological factors associated with a higher risk of developing a severe pituitary apoplexy (PA). METHODS: Multicenter retrospective study of patients presenting with clinical PA in three Spanish tertiary hospitals of Madrid between 2008 and 2022. We classified PA as severe when presenting with an altered level of consciousness (Glasgow Coma Scale (GCS) < 15) or visual involvement. RESULTS: A total of 71 PA cases were identified, of whom 80.28% (n = 57) were classified as severe PA. The median age was 60 (18 to 85 years old) and 67.6% (n = 48) were male. Most patients had macroadenomas, except for one patient with a microadenoma of 9 mm. Headache was the most common presenting symptom (90.1%) and anticoagulation was the most frequent predisposing risk factor, but it was not associated with a higher risk for severe PA (odds ratio [OR] 1.13 [0.21-5.90]). Severe cases were associated with male gender (OR 5.53 [1.59-19.27]), tumor size >20 mm (OR 17.67 [4.07-76.64]), and Knosp grade ≥2 (OR 9.6 [2.38-38.73]). In the multivariant analysis, the only variables associated with a higher risk for severe PA were tumor size and Knosp grade. Surgery was more common in severe PA than in non-severe (91.2% vs. 64.3%, P = 0.009). CONCLUSION: A tumor size >20 mm and cavernous sinus invasion are risk factors for developing a severe PA. These risk factors can stratify patients at a higher risk of a worse clinical picture, and subsequently, more need of decompressive surgery.
Asunto(s)
Adenoma , Apoplejia Hipofisaria , Neoplasias Hipofisarias , Humanos , Masculino , Apoplejia Hipofisaria/epidemiología , Apoplejia Hipofisaria/complicaciones , Persona de Mediana Edad , Femenino , Anciano , Adulto , Estudios Retrospectivos , Factores de Riesgo , Anciano de 80 o más Años , Adulto Joven , Adolescente , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/epidemiología , Neoplasias Hipofisarias/cirugía , Adenoma/epidemiología , Adenoma/complicaciones , Adenoma/cirugía , Índice de Severidad de la Enfermedad , España/epidemiologíaRESUMEN
Not required in Clinical Vignettes.
Asunto(s)
Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT) , Apoplejia Hipofisaria , Neoplasias Hipofisarias , Humanos , Apoplejia Hipofisaria/etiología , Apoplejia Hipofisaria/complicaciones , Hipersecreción de la Hormona Adrenocorticotrópica Pituitaria (HACT)/complicaciones , Neoplasias Hipofisarias/complicaciones , Femenino , Masculino , Persona de Mediana Edad , AdultoRESUMEN
Pituitary apoplexy is a rare and potentially life-threatening clinical syndrome. Patients may present with severeneuro-ophthalmologic or endocrine symptoms. Current evidence is unclear whether conservative or surgicalmanagement leads to the best neuroendocrine outcomes. This study aimed to compare neuroendocrine outcomesbetween surgical and conservative treatments in a single center. Cases of patients with pituitary apoplexy whoreceived transsphenoidal surgery or conservative management in Songklanagarind Hospital between January 1,2005 and December 31, 2022 were retrospectively reviewed. A propensity score matching method was used toadjust bias from treatment selection (surgery or conservative treatment). Differences in visual field, visual acuity,cranial nerve, and endocrine outcomes between the surgical and conservative treatment groups were analyzedusing logistic regression analysis. This study included 127 patients, with 98 and 29 patients in the surgical and theconservative treatment group, respectively. The optimal matching method was used for propensity score matching.Compared to the conservative group, the surgically treated patients had a significantly higher rate of visual fieldrecovery (odds ratio (OR): 12.89, P = 0.007). However, there were no statistical differences in the recovery rate ofpreoperative visual acuity, cranial nerve, and endocrine deficits between the groups. Transsphenoidal surgery wasassociated with a higher rate of visual field recovery when compared to the conservative treatment for pituitaryapoplexy patients. Careful selection of appropriate treatment based on the patient's presentation andneuroendocrine status will result in the best outcomes while avoiding unnecessary surgical intervention.
Asunto(s)
Tratamiento Conservador , Apoplejia Hipofisaria , Puntaje de Propensión , Humanos , Masculino , Femenino , Persona de Mediana Edad , Apoplejia Hipofisaria/cirugía , Apoplejia Hipofisaria/terapia , Tratamiento Conservador/métodos , Anciano , Adulto , Estudios Retrospectivos , Resultado del Tratamiento , Procedimientos Neuroquirúrgicos/métodos , Agudeza Visual/fisiología , Neoplasias Hipofisarias/cirugía , Recuperación de la FunciónRESUMEN
Pituitary apoplexy (PA) is a clinical syndrome resulting from a hemorrhagic infarction of the pituitary gland. It is characterized by the sudden onset of visual disturbances, nausea, vomiting, headache and occasionally, signs of meningeal irritation and an altered mental status. The exact pathogenesis of PA remains to be elucidated, although tumor overgrowth of its blood supply remains the most popular theory. Main risk factors for the development of PA include systemic, iatrogenic, and external factors as well as the presence of an underlying pituitary tumor. The diagnostic approach of PA includes both neuroimaging and evaluation of pituitary secretory function. PA is a potentially life-threatening condition which should be managed with hemodynamic stabilization, correction of electrolyte abnormalities and replacement of hormonal deficiencies. PA treatment should be individualized based on the severity of the clinical picture which may vary widely. Treatment options include conservative management with periodic follow-up or neurosurgical intervention, which should be decided by a multidisciplinary team. We conducted a systematic review of the literature to unveil the frequency of PA predisposing factors, clinical and biochemical presentations, management strategies and outcomes.
Asunto(s)
Apoplejia Hipofisaria , Apoplejia Hipofisaria/diagnóstico , Apoplejia Hipofisaria/terapia , Humanos , Factores de RiesgoRESUMEN
Not required for a Clinical Vignette.
Asunto(s)
Tumores Neuroendocrinos , Apoplejia Hipofisaria , Neoplasias Hipofisarias , Humanos , Apoplejia Hipofisaria/complicaciones , Apoplejia Hipofisaria/diagnóstico , Tumores Neuroendocrinos/diagnóstico , Tumores Neuroendocrinos/diagnóstico por imagen , Neoplasias Hipofisarias/diagnóstico , Neoplasias Hipofisarias/diagnóstico por imagenRESUMEN
Pituitary apoplexy is a rare but potentially life-threatening complication of androgen deprivation therapy for prostate cancer. We present a case of a 70-year-old African American male with prostate cancer who developed symptoms of pituitary apoplexy, including hot flashes, nausea, vomiting, and cranial nerve III palsy, following the initiation of leuprolide therapy. Imaging revealed a pituitary adenoma with hemorrhage, and prompt multidisciplinary management was initiated. The patient was managed conservatively with improvement in symptoms. This case highlights the importance of recognizing the potential for pituitary apoplexy in patients receiving GnRH agonist therapy. We discuss the clinical presentation of GnRH agonist induced pituitary apoplexy, emphasizing that clinicians should maintain a high index of suspicion and promptly investigate any new neuro- ophthalmic symptoms in this group of patients. Ultimately, prompt diagnosis and treatment are crucial to mitigate the severity of this complication in patients with prostate cancer undergoing androgen deprivation therapy.
Asunto(s)
Apoplejia Hipofisaria , Neoplasias de la Próstata , Humanos , Masculino , Anciano , Neoplasias de la Próstata/tratamiento farmacológico , Leuprolida/efectos adversos , Apoplejia Hipofisaria/inducido químicamente , Apoplejia Hipofisaria/diagnóstico , Apoplejia Hipofisaria/tratamiento farmacológico , Antineoplásicos Hormonales/efectos adversos , Antagonistas de Andrógenos/efectos adversos , Andrógenos/uso terapéuticoRESUMEN
Pituitary apoplexy (PA) may be complicated by development of subarachnoid hemorrhage (SAH). We conducted a literature review to evaluate the rate of PA-associated tumor rupture and SAH. We conducted a systematic literature search (PubMed, Web of Science, Medline) for patients with PA-associated SAH and report a case SAH following PA. Suitable articles, case series, and case reports were selected based on predefined criteria following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). We reviewed included publications for clinical, radiological, surgical, and histopathological parameters.We present the case of a patient with PA developing extensive SAH whilst on the MRI who underwent delayed transsphenoidal resection. According to our literature review, we found 55 patients with a median age of 46 years; 18 (32.7%) were female. Factors associated with PA-related SAH were hypertension, diabetes mellitus, prior trauma, anticoagulant, and/or antiplatelet therapy. The most common presenting symptoms included severe headache, nausea and/or vomiting, impaired consciousness, and meningeal irritation. Acute onset was described in almost all patients. Twenty-two of the included patients underwent resection. In patients with available outcome, 45.1% had a favorable outcome, 10 (19.6%) had persisting focal neurological deficits, 7 developed cerebral vasospasms (12.7%), and 18 (35.3%) died. Mortality greatly differed between surgically (9.1%) and non-surgically (44.8%) treated patients. PA-associated SAH is a rare condition developing predominantly in males with previously unknown macroadenomas. Timely surgery often prevents aggravation or development of severe neuro-ophthalmological defects and improves clinical outcome.
Asunto(s)
Adenoma , Apoplejia Hipofisaria , Neoplasias Hipofisarias , Accidente Cerebrovascular , Hemorragia Subaracnoidea , Masculino , Humanos , Femenino , Persona de Mediana Edad , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/diagnóstico por imagen , Neoplasias Hipofisarias/cirugía , Hemorragia Subaracnoidea/complicaciones , Hemorragia Subaracnoidea/diagnóstico por imagen , Apoplejia Hipofisaria/complicaciones , Apoplejia Hipofisaria/diagnóstico por imagen , Apoplejia Hipofisaria/cirugía , Adenoma/complicaciones , Adenoma/diagnóstico por imagen , Adenoma/cirugía , Accidente Cerebrovascular/complicacionesRESUMEN
CONTEXT: Pituitary apoplexy (PA) has been traditionally considered a neurosurgical emergency, yet retrospective single-institution studies suggest similar outcomes among patients managed medically. OBJECTIVE: We established a multicenter, international prospective registry to compare presentation and outcomes in PA patients treated with surgery or medical management alone. METHODS: A centralized database captured demographics, comorbidities, clinical presentation, visual findings, hormonal status, and imaging features at admission. Treatment was determined independently by each site. Key outcomes included visual, oculomotor, and hormonal recovery, complications, and hospital length of stay. Outcomes were also compared based on time from symptom onset to surgery, and from admission or transfer to the treating center. Statistical testing compared treatment groups based on 2-sided hypotheses and P less than .05. RESULTS: A total of 100 consecutive PA patients from 12 hospitals were enrolled, and 97 (67 surgical and 30 medical) were evaluable. Demographics, clinical features, presenting symptoms, hormonal deficits, and imaging findings were similar between groups. Severe temporal visual field deficit was more common in surgical patients. At 3 and 6 months, hormonal, visual, and oculomotor outcomes were similar. Stratifying based on severity of visual fields demonstrated no difference in any outcome at 3 months. Timing of surgery did not affect outcomes. CONCLUSION: We found that medical and surgical management of PA yield similar 3-month outcomes. Although patients undergoing surgery had more severe visual field deficits, we could not clearly demonstrate that surgery led to better outcomes. Even without surgery, apoplectic tumor volumes regress substantially within 2 to 3 months, indicating that surgery is not always needed to reduce mass effect.