Cerebral Venous Sinus Thrombosis Associated With Iron Deficiency-Two Case Reports-

No genetic association between iron deficiency anemia and ischemic stroke and its subtypes: a bidirectional two-sample Mendelian randomization study

Background

Observational researches have suggested a connection between iron deficiency anemia (IDA) and an increased likelihood of ischemic stroke (IS), yet establishing causality is challenging owing to the inherent limitations of such studies, including their vulnerability to confounding factors and the potential for reverse causation. This study employs a bidirectional two-sample Mendelian randomization (MR) approach to assess the causal linkage between IDA and IS and its subtypes.

Methods

Identifiable single nucleotide polymorphisms (SNPs) with significant links to either IDA or IS and its subtypes were employed as instrumental variables (IVs). The relationship between IDA and any IS, small vessel stroke (SVS), cardioembolic stroke (CES), and large artery stroke (LAS), was quantified using the inverse variance weighted (IVW) method. Complementary analyses utilizing MR-Egger and weighted median methods further supplemented the IVW findings. Moreover, the leave-one-out analysis, MR-Egger intercept test, MR-PRESSO global test, and Cochrane's Q test were conducted for sensitivity analyses.

Results

This study revealed no correlation between IDA and any IS (IVW method: OR [95% CI] = 0.977 [0.863-1.106]; p = 0.716), LAS (OR [95% CI] = 1.158 [0.771-1.740]; p = 0.479), CES (OR [95% CI] = 1.065 [0.882-1.285]; p = 0.512), or SVS (OR [95% CI] = 1.138 [0.865-1.498]; p = 0.357). Conducting a reverse MR analysis, it was determined that there is no causal connection between any IS, LAS, CES, SVS, and IDA (all p > 0.05). Sensitivity analysis indicated that heterogeneity was not significant and no evidence of horizontal pleiotropy was detected.

Conclusion

This MR study suggested no causal effect of IDA on IS, LAS, CES, and SVS. Through reverse MR analyses, it was determined that IS and its subtypes did not exert a causal impact on IDA.

Iron deficiency anemia and thrombosis risk in children-revisiting an old hypothesis

Iron deficiency anemia has a high prevalence in children and has repeatedly been implicated as a risk factor for arterial and venous thrombosis. As an effective therapy for iron deficiency anemia is available, understanding the association between this form of anemia and the potentially severe thrombosis phenotype is of major clinical interest. Recent findings shed light on pathophysiology of hypercoagulability resulting from iron-restricted erythropoiesis. Specifically, an animal model of induced iron deficiency allowed identifying multiple mechanisms, by which iron deficiency anemia results in increased thrombus formation and thrombus progression both in arterial and venous thrombosis. These findings complement and support conclusions derived from clinical data. The purpose of this mini review is to summarize current evidence on the association of iron deficiency anemia and thrombosis. We want to increase the awareness of iron deficiency as a risk factor for thrombosis in the pediatric population. We discuss how novel pathophysiological concepts can be translated into the clinical settings and suggest clinical studies on prevention and treatment strategies in high-risk patient groups.

Iron-Deficiency and Estrogen Are Associated With Ischemic Stroke by Up-Regulating Transferrin to Induce Hypercoagulability

RATIONALE

Epidemiological studies have identified an associate between iron deficiency (ID) and the use of oral contraceptives (CC) and ischemic stroke (IS). To date, however, the underlying mechanism remains poorly understood. Both ID and CC have been demonstrated to upregulate the level and iron-binding ability of Tf (transferrin), with our recent study showing that this upregulation can induce hypercoagulability by potentiating FXIIa/thrombin and blocking antithrombin-coagulation proteases interactions.

OBJECTIVE

To investigate whether Tf mediates IS associated with ID or CC and the underlying mechanisms.

METHODS AND RESULTS

Tf levels were assayed in the plasma of IS patients with a history of ID anemia, ID anemia patients, venous thromboembolism patients using CC, and ID mice, and in the cerebrospinal fluid of some IS patients. Effects of ID and estrogen administration on Tf expression and coagulability and the underlying mechanisms were studied in vivo and in vitro. High levels of Tf and Tf-thrombin/FXIIa complexes were found in patients and ID mice. Both ID and estrogen upregulated Tf through hypoxia and estrogen response elements located in the Tf gene enhancer and promoter regions, respectively. In addition, ID, administration of exogenous Tf or estrogen, and Tf overexpression promoted platelet-based thrombin generation and hypercoagulability and thus aggravated IS. In contrast, anti-Tf antibodies, Tf knockdown, and peptide inhibitors of Tf-thrombin/FXIIa interaction exerted anti-IS effects in vivo.

CONCLUSIONS

Our findings revealed that certain factors (ie, ID and CC) upregulating Tf are risk factors of thromboembolic diseases decipher a previously unrecognized mechanistic association among ID, CC, and IS and provide a novel strategy for the development of anti-IS medicine by interfering with Tf-thrombin/FXIIa interactions.

Idiopathic intracranial hypertension in patients with anemia: A retrospective observational study

Idiopathic intracranial hypertension (IIH) mostly affects obese women in childbearing age, leading to frustrating headache and permanent visual impairment. The exact etiology of this condition is poorly understood, and the population at risk and clinical presentation seems to be homogeneous. However, little attention has been paid to the clinical features of IIH patients with anemia. We herein performed a retrospective observational study by using the data of patients with presumed IIH who were referred to the neurology department of Beijing Tongren Hospital from January 2014 to August 2019 to describe the clinical features and radiological findings in patients with IIH and anemia, and compared these with those without anemia. The patients were divided into two groups based on the presence of anemic diseases. Clinical data including demographic characteristics, clinical features, past medical history, laboratory and neuroradiological findings, diagnoses, treatments and prognosis of these patients were reviewed and compared in both the groups. A total of 153 patients with IIH were enrolled, which included 22 cases with anemia (mean age, 33.23±9.68 years; 19 [86.36%] female) and 131 cases without anemia (mean age 37.11±11.56 years; 97 [74.05%] female). In the anemia group, 19/22 cases had iron deficiency anemia and 3/22 had renal anemia. Compared with patients in the non-anemia group, IIH patients with anemia had a shorter disease course, and tended to present pulsatile tinnitus and transverse sinus stenosis (TSS), faster and better prognosis after treatments for correcting anemia and reducing intracranial pressure. Our findings highlighted the importance of obtaining full blood counts in IIH patients with subacute onset, and provided appropriate and prompt treatments if proven anemic in order to bring better outcomes.

Prevalence of Factor V Leiden-G1691A and MTHFR-C677T Thrombosis Gene Modifier in Iron Deficiency Anemia: A Pathophysiological Effect in Indian Isolates

Normal iron levels are required to prevent thrombocytosis by inhibiting thrombopoiesis. Thrombocytosis is usually associated with a mild iron deficiency and is the result of a lack of inhibition of thrombopoiesis. Study participants were 430 iron deficiency anemia (IDA) patients. Ten (10) mL of venous blood were collected for the subjects. Ferritin analysis was done by ELISA method while Hemogram analysis was done by auto-analyzer. Factor V Leiden, PRTG20210A, and MTHFR C677T genotype analysis was performed by PCR-RFLP method. Among the patients, 9 were heterozygous (G>A) and 2 were homozygous (A>A) carrier of FV Leiden; while 20 were heterozygous (C>T) and 3 were homozygous (T>T) for MTHFR polymorphism. None of the patient was identified with PT mutation. Patients with thrombosis gene marker had lower hemoglobin, mean corpuscular volume, mean corpuscular haemoglobin levels, and mean corpuscular hemoglobin concentration than patients without thrombosis gene marker. Serum ferritin was elevated in subject with the absence of thrombosis gene markers. Our data suggest a high impact of inherited hypercoagulability risk factors in the pathogenesis of IDA and its complications.

[Iron deficiency, thrombocytosis and thromboembolism]

Iron deficiency, the most common nutritional deficiency worldwide, is often associated with reactive thrombocytosis. Although secondary thrombocytosis is commonly considered to be harmless, there is accumulating evidence that elevated platelet counts, especially in the setting of iron deficiency, can lead to an increased thromboembolic risk in both arterial and venous systems. Here we present the mechanisms of iron deficiency-induced thrombocytosis and summarize its clinical consequences especially in patients with inflammatory bowel diseases, chronic kidney disease or cancer. We hypothesize that iron deficiency is an underestimated thromboembolic risk factor, and that iron replacement therapy can become an effective preventive strategy in a variety of clinical settings.

Imaging Manifestations of Neurologic Complications in Anemia

The hallmark signs and symptoms of anemia are directly related to a decrease in oxygen delivery to vital tissues and organs and include pallor, fatigue, lightheadedness, and shortness of breath. Neurologic complications are often nonspecific and can include poor concentration, irritability, faintness, tinnitus, and headache. If undiagnosed or untreated, anemia can progress to cognitive dysfunction, psychosis, encephalopathy, myelopathy, peripheral neuropathy, and more focal syndromes, such as stroke, seizures, chorea, and transverse myelitis. Imaging can play an important role in the early diagnosis and treatment of these neurologic and systemic complications associated with anemia, and hence, better outcome.

Clinical Features of Acute Massive Pulmonary Embolism Complicated by Radiofrequency Ablation: An Observational Study

Although pulmonary embolism (PE) complicated by radiofrequency catheter ablation (RFCA) is rare, it can be life-threatening. Our goal was to elucidate the clinical features of acute massive PE after RFCA. Of 2386 patients who underwent RFCA for supraventricular tachycardia or idiopathic ventricular arrhythmia, 4 patients (0.16%) whose cases were complicated by acute massive PE were examined. These 4 patients were female and middle-aged (range 43-52 years), and 2 of the 4 patients had iron-deficiency anemia and reactive thrombocytosis. Ablation in all patients was performed in the left heart via the right femoral arterial approach. All of the patients had a long-duration hemostasis procedure and bed rest following femoral arterial sheath removal after RFCA. All of the patients collapsed and lost consciousness during their first attempt at walking after RFCA. The emergent electrocardiogram in 2 of the 4 patients revealed an S1Q3T3 pattern, 1 patient demonstrated new onset of right bundle-branch block (RBBB) and S1Q3 pattern and Qr pattern in V1, and the remaining patient had negative T waves in leads V1, V2, and III. The emergent echocardiogram revealed right ventricular hypokinesis and pulmonary hypertension in the 4 patients with acute PE after ablation. Although all of the patients initially experienced sinus tachycardia when they recovered consciousness, 2 of the 4 patients suddenly developed intense bradycardia and lost consciousness again, and these patients finally died (50% fatality rate). All of the patients were identified by CT pulmonary angiography or pulmonary angiography. Our report suggests that although acute massive PE is highly rare, there is a real and fatal risk in patients who experienced acute massive PE after RFCA. Particular attention should be paid to the first ambulation after RFCA. Acute PE should be strongly suspected when sudden loss of consciousness occurs upon mobilization after RFCA. The new onset of S1Q3T3 pattern, RBBB or T wave inversion in the right precordial leads, and early detection of echocardiographic right ventricular dysfunction may be useful for making an early diagnosis of acute PE after RFCA. Early ambulation after left-sided RFCA might be helpful to prevent the formation of deep venous thrombosis and subsequent PE.

Association Between Anemia and Cerebral Venous Thrombosis: Case-Control Study

BACKGROUND AND PURPOSE

Anemia is often considered to be a risk factor for cerebral venous thrombosis (CVT), but this assumption is mostly based on case reports. We investigated the association between anemia and CVT in a controlled study.

METHODS

Unmatched case-control study: cases were adult patients with CVT included in a single-center, prospective database between July 2006 and December 2014. Controls were subjects from the control population of the Multiple Environmental and Genetic Assessment of Risk Factors for Venous Thrombosis (MEGA) study. Anemia was defined according to World Health Organization criteria: nonpregnant women hemoglobin<7.5 mmol/L, pregnant women<6.9 mmol/L, and men<8.1 mmol/L. We used logistic regression analysis, adjusting for age, sex, malignancy, oral contraceptive use, and pregnancy/puerperium.

RESULTS

We included 152 cases and 2916 controls. Patients with CVT were younger (mean age, 40 versus 48 years) and more often women (74% versus 53%) than controls. Anemia was more frequent in cases (27.0%) than in controls (6.5%; P<0.001). Anemia was associated with CVT, both in univariate analysis (odds ratio, 5.3; 95% confidence interval [CI], 3.6-7.9) and after adjustment for potential confounders (adjusted odds ratio, 4.4; 95% CI, 2.8-6.9). Hemoglobin as a continuous variable was inversely associated with CVT (adjusted odds ratio per 1 mmol/L change 0.53; 95% CI, 0.42-0.66). Stratification by sex showed a stronger association between anemia and CVT in men (adjusted odds ratio, 9.9; 95% CI, 4.1-23.8) than in women (3.6; 95% CI, 2.1-6.0).

CONCLUSION

Our data suggest that anemia is a risk factor for CVT.

Iron repletion is associated with reduction in platelet counts in non-dialysis chronic kidney disease patients independent of erythropoiesis-stimulating agent use: a retrospective cohort study

Background

Iron deficiency is common in non-dialysis chronic kidney disease (ND-CKD) patients and, on occasion, requires parenteral iron therapy. We investigated the effect of intravenous iron repletion on platelet counts in ND-CKD patients with and without concomitant darbepoetin administration.

Methods

We conducted a retrospective analysis of ND-CKD patients with iron deficiency anemia treated with low molecular weight iron dextran (LMWID) between 2005 and 2009 at our CKD clinic. The primary end-point was change in platelet count 60 days post infusion of LMWID in those with and without concomitant darbepoetin administration. Secondary end-points were the correlations between changes in platelet count and iron indices.

Results

A total of 108 patients met inclusion and exclusion criteria. The decrease in platelet counts in response to iron repletion was statistically significant (305.72 ± 108.86 vs 255.58 ± 78.97, P = < .0001). The decrease in platelet count was independent of concomitant darbepoetin use. Bivariate regression analysis between baseline platelet count and transferrin saturation by iron (TSAT) showed a negative association (β_TSAT = −5.82, P = .0007) and moderate correlation (R = 0.32). Following iron treatment, the within individual changes in platelet count in 60 days were not related to changes in TSAT (β_ΔTSAT = −0.41, P = .399) and demonstrated a poor correlation (R = 0.10).

Conclusions

Parenteral iron treatment by LMWID is associated with reduction in platelet counts in iron deficient anemic ND-CKD patients. However, ESA use in the majority of patients prior to intravenous iron administration could have altered platelet production through bone marrow competition.

Isolated lateral sinus thrombosis presenting as cerebellar infarction in a patient with iron deficiency anemia

As a rare cerebrovascular disease, cerebral venous thrombosis (CVT) is caused by various conditions including trauma, infection, oral contraceptive, cancer and hematologic disorders. However, iron deficiency anemia is not a common cause for CVT in adult. Posterior fossa infarction following CVT is not well demonstrated because posterior fossa has abundant collateral vessels. Here, we report a case of a 55-year-old man who was admitted with complaints of headache, nausea, and mild dizziness. The patient was diagnosed with isolated lateral sinus thrombosis presenting as cerebellar infarction. Laboratory findings revealed normocytic normochromic anemia due to iron deficiency, and the patient's symptoms were improved after iron supplementation.

Unusual causes of papilledema: Two illustrative cases

Background:

Neurosurgeons are frequently among the first physicians asked to evaluate patients with papilledema, and the patient is often referred with the implication that they may require shunting. After an initial evaluation to exclude potential neurosurgical emergencies, the physician should carefully consider various etiologies of papilledema to prevent unnecessary neurosurgical operations.

Case Description:

The authors report two illustrative cases of unusual causes of papilledema: Anemia and leukemic infiltration of the central nervous system. In each case, a complete blood count provided clues for the diagnosis. A review of the literature is also included.

Conclusions:

Both patients responded to medical management/treatment of the underlying disease and did not require neurosurgical operative intervention. Papilledema may be caused by other etiologies besides increased intracranial pressure. The authors present two unusual cases leading to papilledema and provide an outline for the workup of these conditions.

Intravenous Iron Repletion Does Not Significantly Decrease Platelet Counts in CKD Patients with Iron Deficiency Anemia

Purpose. We sought to investigate the effect of IV iron repletion on platelet (PLT) counts in CKD patients with iron deficiency anemia (IDA). Methods. We conducted a retrospective chart review, including all patients with CKD and IDA who were treated with iron dextran total dose infusion (TDI) between 2002 and 2007. Patient demographics were noted, and laboratory values for creatinine, hemoglobin (Hgb), iron stores and PLT were recorded pre- and post-dose. Results. 153 patients received a total of 251 doses of TDI (mean ± SD = 971 ± 175 mg); age 69 ± 12 years and Creatinine 3.3 ± 1.9 mg/dL. All CKD stages were represented (stage 4 commonest). Hgb and Fe stores improved post-TDI (P ≪ 0.001). There was a very mild decrease in PLT (pre-TDI 255 versus post-TDI 244, P = 0.30). The mild reduction in PLT after TDI remained non-significant (P > 0.05) when data was stratified by molecular weight (MW) of iron dextran used (low versus high), as well as by dose administered (<1000 versus ≥1000 mg). Linear regression analysis between pre-dose PLT and Tsat and Fe showed R2 of 0.01 and 0.04, respectively. Conclusion. Correction of iron deficiency did not significantly lower PLT in CKD patients, regardless of MW or dose used. Correlation of PLT to severity of iron deficiency was very weak.

Effect of iron therapy on platelet counts in patients with inflammatory bowel disease-associated anemia

Background and Aims

Secondary thrombocytosis is a clinical feature of unknown significance. In inflammatory bowel disease (IBD), thrombocytosis is considered a marker of active disease; however, iron deficiency itself may trigger platelet generation. In this study we tested the effect of iron therapy on platelet counts in patients with IBD-associated anemia.

Methods

Platelet counts were analyzed before and after iron therapy from four prospective clinical trials. Further, changes in hemoglobin, transferrin saturation, ferritin, C-reactive protein, and leukocyte counts, before and after iron therapy were compared. In a subgroup the effect of erythropoietin treatment was tested. The results were confirmed in a large independent cohort (FERGIcor).

Results

A total of 308 patient records were available for the initial analysis. A dose-depended drop in platelet counts (mean 425 G/L to 320 G/L; p<0.001) was found regardless of the type of iron preparation (iron sulphate, iron sucrose, or ferric carboxymaltose). Concomitant erythropoietin therapy as well as parameters of inflammation (leukocyte counts, C-reactive protein) had no effect on the change in platelet counts. This effect of iron therapy on platelets was confirmed in the FERGIcor study cohort (n=448, mean platelet counts before iron therapy: 383 G/L, after: 310 G/L, p<0.001).

Conclusion

Iron therapy normalizes elevated platelet counts in patients with IBD-associated anemia. Thus, iron deficiency is an important pathogenetic mechanism of secondary thrombocytosis in IBD.

Iron deficiency: beyond anemia

Iron deficiency is the most common nutritional disorder affecting at least one third of world's population. Though anemia is common manifestation of iron deficiency, other effects of iron deficiency on various tissues, organs and systems are usually under recognized. Impaired brain development and cognitive, behavioural and psychomotor impairment are most worrisome manifestations of iron deficiency. Studies have demonstrated that some of these changes occurring during period of brain growth spurt (<2 years age) may be irreversible. Association of iron deficiency with febrile seizures, pica, breath holding spells, restless leg syndrome and thrombosis is increasingly being recognized. Impaired cell-mediated immunity and bactericidal function are generally noted in iron-deficient persons; however, the findings are inconsistent. Despite proven reversible functional immunological defects in vitro studies, a clinically important relationship between states of iron deficiency and susceptibility to infections remains controversial. Studies from malaria endemic regions have reported increased incidence of malaria in association with iron supplementation. These and some other aspects of iron deficiency are reviewed in this article.

Childhood and teenage stroke

OBJECTIVE

The purpose of this manuscript is to review the various etiologies and to discuss the therapeutic issues in childhood stroke.

METHODS

A PubMed search of literature pertaining to childhood stroke was conducted from 1983 to 2008 using specific key search words pertinent to cerebrovascular disorders in childhood.

RESULTS

The analysis of the multiple causes of childhood stroke including arterial ischemic strokes and cerebral venous thrombosis was presented. Current therapy and outcome data in childhood stroke are also discussed throughout the length of the article.

CONCLUSIONS

With increasing vigilance among physicians and improved neuroimaging modalities, the diagnosis of childhood stroke is now made earlier, with increasing frequency and greater accuracy. However, larger and well-controlled studies regarding the optimal management of childhood stroke in terms of the use of both antithrombotic drugs and anticoagulation are still needed in addition to longitudinal follow-up studies of children with stroke.

Cerebral venous sinus thrombosis risk factors

Cerebral venous sinus thrombosis is an uncommon disease marked by clotting of blood in cerebral venous, or dural sinuses, and, in rare cases, cortical veins. It is a rare but potentially fatal cause of acute neurological deterioration previously related to otomastoid, orbit, and central face cutaneous infections. After the advent of antibiotics, it is more often related to neoplasm, pregnancy, puerperium, systemic diseases, dehydration, intracranial tumors, oral contraceptives, and coagulopathies are the most common causes, but in 30% of cases no underlying etiology can be identified. It has been found in association with fibrous thyroiditis, jugular thrombosis after catheterization, or idiopathic jugular vein stenosis. Other factors include surgery, head trauma, arterio-venous malformations, infection, paraneoplastic, and autoimmune disease. This article presents a comprehensive review of cerebral venous sinus thrombosis etiologies.

Iron and thrombosis

Although essential for cell physiology, an increase or depletion of body iron has harmful effects on health. Apart from iron deficiency anemia and iron overload-related organ tissue damage, there are increasing evidences that body iron status is implicated in atherosclerotic cardiovascular diseases. The hypothesis formulated in 1981 that iron depletion may protect against cardiovascular events is intriguing and has generated a significant debate in the last two decades. Indeed, to study this phenomenon, several investigators have tried to design appropriate experimental and clinical studies and to identify useful biochemical and genetic markers of iron status. The results of the literature on the effect of iron deficiency and overload on vascular health are critically reviewed in this study from a pathogenic and clinical point of view.