Severe iron deficiency anaemia and stroke

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.

Relationship between oxidant-antioxidant status and hypercoagulobility indices in children with iron deficiency anaemia

Oxidative stress is a potential mechanism involved in the pathogenesis of iron deficiency anaemia (IDA). Although a tendency for hypercoagulability has been reported in IDA, its underlying mechanism is yet to be elucidated. This study investigated the probable relationship between oxidative stress and hypercoagulability in children with IDA. This study included 57 children diagnosed with IDA (IDA group) between October 2016 and October 2017 in addition to 48 healthy children (control group). The maximum clot firmness (MCF) index, and clot formation time (CFT) index, which are indicators of hypercoagulability in rotational thromboelastometry assays [intrinsic TEM (INTEM) and extrinsic TEM (EXTEM)] derived from our previous study, were recorded. Total oxidant status (TOS), total antioxidant capacity (TAC) and oxidative stress index (OSI) were analysed from serum samples of the individuals. In IDA group, OSI and TOS levels were higher and TAC level was lower compared to the control group (P < 0.001, for all). The EXTEM and INTEM MCF in the IDA group was higher than in the control group, while the INTEM CFT was lower than in the control group (P < 0.001, P < 0.001, P < 0.05, published data).TOS and OSI had a negative correlation with INTEM CFT (r:-0.361, P < 0.001 and r:-0.333, P = 0.001) and a positive correlation with INTEM MCF (r:+0.420, P < 0.001 and r:+0.367, P < 0.001) and EXTEM MCF (r:+0.476, P < 0.001 and r:+0.403, P < 0.001). However, TAC demonstrated no correlation with CFT and MCF index. The oxidant-antioxidant balance is disrupted in favour of oxidative stress in children with IDA. In addition, TOS and OSI, which are parameters of oxidative stress, are correlated with CFT and MCF indices. Oxidative stress appears to be an important factor for the development of tendency to hypercoagulability in IDA.

Iron Deficiency Anemia: An Unexpected Cause of an Acute Occipital Lobe Stroke in an Otherwise Healthy Young Woman

A 29-year-old caucasian woman who presented to the hospital with an acute onset of right eye visual disturbance and headache was found to have an acute left occipital lobe infarction. Past medical history was significant for iron deficiency anemia (IDA) secondary to menorrhagia. Her initial hemoglobin level was 7.8 G/DL, and her symptoms improved after iron and blood transfusions. Hypercoagulable studies were completed in the outpatient setting, and the results were unremarkable. Her acute stroke was most likely related to IDA as she had low cardiovascular risk factors along with a negative complete stroke workup.

Iron Status and Risk of Stroke

Background and Purpose- Both iron deficiency and excess have been associated with stroke risk in observational studies. However, such associations may be attributable to confounding from environmental factors. This study uses the Mendelian randomization technique to overcome these limitations by investigating the association between genetic variants related to iron status and stroke risk. Methods- A study of 48 972 subjects performed by the Genetics of Iron Status consortium identified genetic variants with concordant relations to 4 biomarkers of iron status (serum iron, transferrin saturation, ferritin, and transferrin) that supported their use as instruments for overall iron status. Genetic estimates from the MEGASTROKE consortium were used to investigate the association between the same genetic variants and stroke risk. The 2-sample ratio method Mendelian randomization approach was used for the main analysis, with the MR-Egger and weighted median techniques used in sensitivity analyses. Results- The main results, reported as odds ratio (OR) of stroke per SD unit increase in genetically determined iron status biomarker, showed a detrimental effect of increased iron status on stroke risk (serum iron OR, 1.07; 95% CI, 1.01-1.14; [log-transformed] ferritin OR, 1.18; 95% CI, 1.02-1.36; and transferrin saturation OR, 1.06; 95% CI, 1.01-1.11). A higher transferrin, indicative of lower iron status, was also associated with decreased stroke risk (OR, 0.92; 95% CI, 0.86-0.99). Examining ischemic stroke subtypes, we found the detrimental effect of iron status to be driven by cardioembolic stroke. These results were supported in statistical sensitivity analyses more robust to the inclusion of pleiotropic variants. Conclusions- This study provides Mendelian randomization evidence that higher iron status is associated with increased stroke risk and, in particular, cardioembolic stroke. Further work is required to investigate the underlying mechanism and whether this can be targeted in preventative strategies.

[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.

Association between iron deficiency and febrile seizures

OBJECTIVE

The relationship between iron status and febrile seizures has been examined in various settings, mainly in the Developing World, with conflicting results. The aim of this study was to investigate any association between iron deficiency and febrile seizures (FS) in European children aged 6-60 months.

DESIGN

Prospective, case-control study.

SETTING

Greek population in Thessaloniki.

PATIENTS

50 patients with febrile seizures (cases) and 50 controls (children presenting with fever, without seizures).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Haematologic parameters (haemoglobin concentration, haematocrit, mean corpuscular volume, red cell distribution width), plasma iron, total iron-binding capacity, plasma ferritin, transferrin saturation and soluble transferrin receptors were compared in cases and controls.

RESULTS

Plasma ferritin was lower (median [range]: 42.8 (3-285.7) vs 58.3 (21.4-195.3 ng/ml; p = 0.02) and Total Iron Binding Capacity (TIBC) higher (mean [Standard Deviation] 267 [58.9] vs 243 [58.45] μg/dl, p = 0.04) in cases than in controls. Results were similar for 12 complex FS cases (ferritin 30 (3-121 vs 89 (41.8-141.5ng/lL; TIBC 292.92 [68.0] vs 232.08 [36.27] μg/dL). Iron deficiency, defined as ferritin <30 ng/ml, was more frequent in cases (24%) than controls (4%; p = 0.004). Ferritin was lower and TIBC higher in 18 with previous seizures than in 32 with a first seizure although haemoglobin and mean cell haemoglobin concentration were higher.

CONCLUSIONS

European children with febrile seizures have lower Ferritin than those with fever alone, and iron deficiency, but not anaemia, is associated with recurrence. Iron status screening should be considered as routine for children presenting with or at high risk for febrile seizures.

Iron-Deficiency Anemia Leading to Transient Ischemic Attacks due to Intraluminal Carotid Artery Thrombus

Reactive thrombocytosis secondary to iron-deficiency anemia (IDA) is a rare but recognized cause of stroke. We report the case of a patient with iron-deficiency anemia presenting with multiple transient ischemic attacks (TIA) due to intraluminal thrombus of an internal carotid artery. The putative mechanisms underlying anemia and stroke syndromes are not completely understood, and it is believed that iron deficiency may cause ischemic stroke by several potential mechanisms. Thrombocytosis is often associated with iron deficiency, and microcytosis produces a reduction in the red cell deformability and could produce a hypercoagulable state. The platelet count and function observed in iron-deficiency anemia could act synergistically to promote thrombus formation, especially in the setting of an underlying atherosclerotic disease. The presence of floating thrombus in a patient with clinical and MRI evidence of stroke represents a significant therapeutic dilemma and requires immediate decision about treatment.

Dural scalp and intracranial hemangiomas causing hydrocephalus and venous sinus thrombosis in an infant

Cutaneous scalp hemangiomas may herald the presence of occult intracranial hemangiomas. A previously healthy 4-month-old girl presented with a bleeding scalp hemangioma, a bulging fontanel, and anemia. Magnetic resonance imaging (MRI) of the brain revealed hydrocephalus along with multiple intracranial hemangiomas. These lesions compressed the jugular foramina, resulting in venous sinus thrombosis involving the right transverse sinus, the left sigmoid sinus, and the torcular herophili. The patient had no family history of phakomatoses or other genetic abnormalities. A thrombophilia work-up result was unremarkable. The patient was treated with prednisolone (10 mg twice daily) and low molecular weight heparin (1 mg/kg/dose) twice daily. This treatment decreased the size of her cutaneous and intracranial hemangiomas and led to the resolution of her venous sinus thromboses and hydrocephalus. Innocuous scalp hemangioma in an infant may herald more concerning intracranial pathology, which can be treated effectively if diagnosed with appropriate imaging studies.

Hemorheological parameters in children with iron-deficiency anemia and the alterations in these parameters in response to iron replacement

AIM

Iron-deficiency anemia (IDA) is a common disorder in pediatric patients. There are a limited number of studies having controversial results in investigating red blood cell (RBC) deformability and aggregation in adult IDA patients. The aim of this study is to determine the change of hemorheological parameters, including RBC deformability, aggregation, and plasma and whole blood viscosity, in children with IDA following iron supplementation therapy.

MATERIALS AND METHODS

The study was performed on 20 children with IDA (average age 35.5 +/- 6.5 months) and 20 age-matched healthy children. The anemia group was treated with 5 mg/kg/day peroral iron for 2 months. Hematological and hemorheological parameters were determined before and after treatment. An ectacytometer was used for the assessment of RBC deformability and aggregation and a cone-plate rotational viscometer for plasma and whole blood viscosities. Hematological parameters were determined using an electronic hematology analyzer.

RESULTS

Although IDA resulted in a decrement in RBC deformability, aggregation, plasma, and whole blood viscosities, these parameters returned to control values after iron supplementation therapy. Serum ferritin levels and hematological parameters (Hb, MCV, MCH, MCHC) that were lower in IDA patients were also found to be increased after treatment.

CONCLUSION

Iron treatment not only reverses the symptoms of anemia but also may contribute to blood flow regulation by causing increments in the alterations observed in hemorheological parameters during anemia.

Unilateral venous thalamic infarction in a child mimicking a thalamic tumor

Unilateral thalamic infarction is a rare condition in adults. This is a case report of a young child presenting with left-sided hemiparesis of sudden onset due to an unilateral venous thalamic infarction. This was attributed to an asymmetric thrombosis of the cerebral internal veins, a partial thrombosis of the vein of Galen and straight sinus. Magnetic resonance imaging resulted primarily in the differential diagnosis of a cerebral tumor or an intracerebral abscess, leading to stereotactic puncture. Subsequent magnetic resonance venography facilitated the correct diagnosis. Heparin-induced thrombocytopenia necessitated anticoagulation treatment with hirudin and later, warfarin. The patient made a complete recovery. We conclude that unclear unilateral thalamic lesions might be symptomatic of a cerebral deep venous thrombosis and might mimic a thalamic tumor. In uncertain cases, we suggest rapid performance of magnetic resonance angiography.

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.

Association between iron-deficiency anemia and stroke in young children

OBJECTIVE

Iron-deficiency anemia occurs with a peak prevalence of 4% to 8% in children between 1 and 3 years of age. Case reports have suggested an association between iron-deficiency anemia in healthy children and ischemic stroke. Our objective was to investigate whether iron-deficiency anemia is associated with stroke in young children.

METHODS

A case-control study was conducted of case patients who were selected from the stroke registry at the Hospital for Sick Children (Toronto, Ontario, Canada) and control subjects selected from a database of healthy children who were prospectively enrolled in an outpatient setting. Children were aged 12 to 38 months and were previously healthy with no identifiable risk factors for stroke. Age, gender, mean corpuscular volume, platelet count, and hemoglobin and ferritin levels were collected. Iron-deficiency anemia was defined as a hemoglobin level of <110 g/L, mean corpuscular volume <73 fL, and serum ferritin level <12 microg/L. Stroke was defined according to clinical and radiologic criteria.

RESULTS

Case (n = 15) and control (n = 143) subjects were similar with respect to median age and percentage of boys. Case patients had a lower median hemoglobin level and mean corpuscular volume and a higher median platelet count. Iron-deficiency anemia was significantly more common among case patients (8 [53%] of 15) than control subjects (13 [9%] of 143).

CONCLUSIONS

Previously healthy children with stroke were 10 times more likely to have iron-deficiency anemia than healthy children without stroke. Furthermore, children with iron-deficiency anemia accounted for more than half of all stroke cases in children without an underlying medical illness, which suggests that iron-deficiency anemia is a significant risk factor for stroke in otherwise healthy young children. Primary prevention and early identification of iron-deficiency anemia must remain a priority.

Prothrombotic abnormalities in childhood ischaemic stroke

Childhood ischaemic stroke, incorporating arterial ischaemic stroke and cerebral sinus venous thrombosis, is associated with significant morbidity and mortality in children. The majority of cases in children present with well-recognised risk factors. The appreciation of the role prothrombotic abnormalities have in disease states is developing rapidly. Prothrombotic abnormalities are abnormalities of the coagulation system, fibrinolytic system, endothelial cells or platelets that lead to a reduced threshold for pathological thrombus formation. Our understanding of the role of prothrombotic abnormalities in childhood ischaemic stroke is increasing and has a direct bearing on the development of effective management and prevention strategies. We provide a brief background of prothrombotic abnormalities and review the available literature on prothrombotic markers in childhood ischaemic stroke. Overall, prothrombotic abnormalities have been identified in 20-50% of children presenting with AIS and 33-99% of children with cerebral sinus venous thrombosis. There appear to be a number of associations emerging including an increased frequency of factor V Leiden mutation, elevated lipoprotein (a), protein C deficiency and antiphospholipid antibodies in children presenting with arterial ischaemic stroke. The pathogenic role of prothrombotic abnormalities as predisposing to initial and recurrent childhood ischaemic stroke is becoming increasingly evident. The impact on treatment, however, will only be clarified with carefully designed, multi-institutional prospective studies.

Iron deficiency and thrombosis: literature review

Compared to primary thrombocytosis such as that caused by essential thrombocytosis, reactive thrombocytosis is generally regarded as benign. However, reactive thrombocytosis has infrequently been reported to cause severe and even fatal complications. Two fatal cases of reactive thrombocytosis and iron deficiency anemia associated with peripheral/pulmonary vascular and cerebrovascular thrombosis are described. The literature on thrombosis and reactive thrombocytosis associated with iron deficiency anemia is reviewed.

Cerebral sinovenous thrombosis in children: another reason to treat iron deficiency anemia

Iron deficiency anemia is a rare cause of cerebral sinovenous thrombosis in children. We report three cases of cerebral sinovenous thrombosis and iron deficiency anemia treated at Primary Children's Medical Center in Salt Lake City, Utah, between 1998 and 2001. The children were 9, 19, and 27 months old at the time of admission. Hemoglobin levels ranged from 6.6 to 7.0 g/dL, mean corpuscular volume levels from 45 to 56 fL, and platelet counts from 248,000 to 586,000/microL. Magnetic resonance imaging and magnetic resonance venography revealed thrombosis of the straight sinus and internal cerebral veins in all three children, with the addition of the vein of Galen, left transverse and sigmoid sinuses, and upper left internal jugular vein in one child. Recovery ranged from excellent to poor in 3 months to 3 years of follow-up. Four additional cases, ages 6 to 22 months, were found in the English-language literature. Evaluation for prothrombotic disorders was negative in all children, including the current cases. Treatments have included thrombectomy, corticosteroids, mannitol, heparin, low-molecular-weight heparin, warfarin, aspirin, blood transfusion, and iron supplementation, but there is no consensus regarding therapy, other than to correct the anemia and treat iron deficiency. Iron deficiency anemia, a preventable cause of cerebral sinovenous thrombosis, deserves consideration when cerebral sinovenous thrombosis is detected in young children.

Neurologic manifestations of iron deficiency in childhood

Iron deficiency is a common disorder in pediatric patients. Although the most common manifestation is that of anemia, iron deficiency is frequently the source of a host of neurologic disorders presenting to general pediatric neurologic practices. These disorders include developmental delay, stroke, breath-holding episodes, pseudotumor cerebri, and cranial nerve palsies. Although frequent, the identification of iron deficiency as part of the differential diagnosis in these disorders is uncommon and frequently goes untreated. The purpose of the current review is to highlight what is understood regarding iron deficiency and it's underlying pathophysiology as it relates to the brain, and the association of iron deficiency with common neurologic pediatric disease.