Hemorrhage: Bleeding or escape of blood from a vessel.Cerebral Hemorrhage: Bleeding into one or both CEREBRAL HEMISPHERES including the BASAL GANGLIA and the CEREBRAL CORTEX. It is often associated with HYPERTENSION and CRANIOCEREBRAL TRAUMA.Subarachnoid Hemorrhage: Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.Intracranial Hemorrhages: Bleeding within the SKULL, including hemorrhages in the brain and the three membranes of MENINGES. The escape of blood often leads to the formation of HEMATOMA in the cranial epidural, subdural, and subarachnoid spaces.Retinal Hemorrhage: Bleeding from the vessels of the retina.Postpartum Hemorrhage: Excess blood loss from uterine bleeding associated with OBSTETRIC LABOR or CHILDBIRTH. It is defined as blood loss greater than 500 ml or of the amount that adversely affects the maternal physiology, such as BLOOD PRESSURE and HEMATOCRIT. Postpartum hemorrhage is divided into two categories, immediate (within first 24 hours after birth) or delayed (after 24 hours postpartum).Gastrointestinal Hemorrhage: Bleeding in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.Vitreous Hemorrhage: Hemorrhage into the VITREOUS BODY.Eye Hemorrhage: Intraocular hemorrhage from the vessels of various tissues of the eye.Basal Ganglia Hemorrhage: Bleeding within the subcortical regions of cerebral hemispheres (BASAL GANGLIA). It is often associated with HYPERTENSION or ARTERIOVENOUS MALFORMATIONS. Clinical manifestations may include HEADACHE; DYSKINESIAS; and HEMIPARESIS.Vasospasm, Intracranial: Constriction of arteries in the SKULL due to sudden, sharp, and often persistent smooth muscle contraction in blood vessels. Intracranial vasospasm results in reduced vessel lumen caliber, restricted blood flow to the brain, and BRAIN ISCHEMIA that may lead to hypoxic-ischemic brain injury (HYPOXIA-ISCHEMIA, BRAIN).Intracranial Hemorrhage, Hypertensive: Bleeding within the SKULL that is caused by systemic HYPERTENSION, usually in association with INTRACRANIAL ARTERIOSCLEROSIS. Hypertensive hemorrhages are most frequent in the BASAL GANGLIA; CEREBELLUM; PONS; and THALAMUS; but may also involve the CEREBRAL CORTEX, subcortical white matter, and other brain structures.Postoperative Hemorrhage: Hemorrhage following any surgical procedure. It may be immediate or delayed and is not restricted to the surgical wound.Hematoma: A collection of blood outside the BLOOD VESSELS. Hematoma can be localized in an organ, space, or tissue.Intracranial Aneurysm: Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)Choroid Hemorrhage: Hemorrhage from the vessels of the choroid.Peptic Ulcer Hemorrhage: Bleeding from a PEPTIC ULCER that can be located in any segment of the GASTROINTESTINAL TRACT.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Putaminal Hemorrhage: Intracranial bleeding into the PUTAMEN, a BASAL GANGLIA nucleus. This is associated with HYPERTENSION and lipohyalinosis of small blood vessels in the putamen. Clinical manifestations vary with the size of hemorrhage, but include HEMIPARESIS; HEADACHE; and alterations of consciousness.Cerebral Angiography: Radiography of the vascular system of the brain after injection of a contrast medium.Aneurysm, Ruptured: The tearing or bursting of the weakened wall of the aneurysmal sac, usually heralded by sudden worsening pain. The great danger of a ruptured aneurysm is the large amount of blood spilling into the surrounding tissues and cavities, causing HEMORRHAGIC SHOCK.Retrobulbar Hemorrhage: Hemorrhage within the orbital cavity, posterior to the eyeball.Cerebral Ventricles: Four CSF-filled (see CEREBROSPINAL FLUID) cavities within the cerebral hemispheres (LATERAL VENTRICLES), in the midline (THIRD VENTRICLE) and within the PONS and MEDULLA OBLONGATA (FOURTH VENTRICLE).Cerebral Hemorrhage, Traumatic: Bleeding into one or both CEREBRAL HEMISPHERES due to TRAUMA. Hemorrhage may involve any part of the CEREBRAL CORTEX and the BASAL GANGLIA. Depending on the severity of bleeding, clinical features may include SEIZURES; APHASIA; VISION DISORDERS; MOVEMENT DISORDERS; PARALYSIS; and COMA.Shock, Hemorrhagic: Acute hemorrhage or excessive fluid loss resulting in HYPOVOLEMIA.Rupture, Spontaneous: Tear or break of an organ, vessel or other soft part of the body, occurring in the absence of external force.Brain Hemorrhage, Traumatic: Bleeding within the brain as a result of penetrating and nonpenetrating CRANIOCEREBRAL TRAUMA. Traumatically induced hemorrhages may occur in any area of the brain, including the CEREBRUM; BRAIN STEM (see BRAIN STEM HEMORRHAGE, TRAUMATIC); and CEREBELLUM.Hematoma, Subdural: Accumulation of blood in the SUBDURAL SPACE between the DURA MATER and the arachnoidal layer of the MENINGES. This condition primarily occurs over the surface of a CEREBRAL HEMISPHERE, but may develop in the spinal canal (HEMATOMA, SUBDURAL, SPINAL). Subdural hematoma can be classified as the acute or the chronic form, with immediate or delayed symptom onset, respectively. Symptoms may include loss of consciousness, severe HEADACHE, and deteriorating mental status.Intracranial Arteriovenous Malformations: Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.Hydrocephalus: Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, INTRACRANIAL HYPERTENSION; HEADACHE; lethargy; URINARY INCONTINENCE; and ATAXIA.Oral Hemorrhage: Bleeding from the blood vessels of the mouth, which may occur as a result of injuries to the mouth, accidents in oral surgery, or diseases of the gums.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Ventriculostomy: Surgical creation of an opening in a cerebral ventricle.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Cerebral Ventriculography: Radiography of the ventricular system of the brain after injection of air or other contrast medium directly into the cerebral ventricles. It is used also for x-ray computed tomography of the cerebral ventricles.Stroke: A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)Basilar Artery: The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.Brain Ischemia: Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.Embolization, Therapeutic: A method of hemostasis utilizing various agents such as Gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and INTRACRANIAL ARTERIOVENOUS MALFORMATIONS, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage.Uterine Hemorrhage: Bleeding from blood vessels in the UTERUS, sometimes manifested as vaginal bleeding.Tissue Plasminogen Activator: A proteolytic enzyme in the serine protease family found in many tissues which converts PLASMINOGEN to FIBRINOLYSIN. It has fibrin-binding activity and is immunologically different from UROKINASE-TYPE PLASMINOGEN ACTIVATOR. The primary sequence, composed of 527 amino acids, is identical in both the naturally occurring and synthetic proteases.Thalamic Diseases: Disorders of the centrally located thalamus, which integrates a wide range of cortical and subcortical information. Manifestations include sensory loss, MOVEMENT DISORDERS; ATAXIA, pain syndromes, visual disorders, a variety of neuropsychological conditions, and COMA. Relatively common etiologies include CEREBROVASCULAR DISORDERS; CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; BRAIN HYPOXIA; INTRACRANIAL HEMORRHAGES; and infectious processes.Intracranial Hemorrhage, Traumatic: Bleeding within the SKULL induced by penetrating and nonpenetrating traumatic injuries, including hemorrhages into the tissues of CEREBRUM; BRAIN STEM; and CEREBELLUM; as well as into the epidural, subdural and subarachnoid spaces of the MENINGES.Fetomaternal Transfusion: Transplacental passage of fetal blood into the circulation of the maternal organism. (Dorland, 27th ed)Glasgow Coma Scale: A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Uterine Inertia: Failure of the UTERUS to contract with normal strength, duration, and intervals during childbirth (LABOR, OBSTETRIC). It is also called uterine atony.Cerebral Arteries: The arterial blood vessels supplying the CEREBRUM.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.Fibrinolytic Agents: Fibrinolysin or agents that convert plasminogen to FIBRINOLYSIN.Cerebral Infarction: The formation of an area of NECROSIS in the CEREBRUM caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Brain Edema: Increased intracellular or extracellular fluid in brain tissue. Cytotoxic brain edema (swelling due to increased intracellular fluid) is indicative of a disturbance in cell metabolism, and is commonly associated with hypoxic or ischemic injuries (see HYPOXIA, BRAIN). An increase in extracellular fluid may be caused by increased brain capillary permeability (vasogenic edema), an osmotic gradient, local blockages in interstitial fluid pathways, or by obstruction of CSF flow (e.g., obstructive HYDROCEPHALUS). (From Childs Nerv Syst 1992 Sep; 8(6):301-6)Acute Disease: Disease having a short and relatively severe course.Anticoagulants: Agents that prevent clotting.Cerebellar Diseases: Diseases that affect the structure or function of the cerebellum. Cardinal manifestations of cerebellar dysfunction include dysmetria, GAIT ATAXIA, and MUSCLE HYPOTONIA.Cerebral Amyloid Angiopathy: A heterogeneous group of sporadic or familial disorders characterized by AMYLOID deposits in the walls of small and medium sized blood vessels of CEREBRAL CORTEX and MENINGES. Clinical features include multiple, small lobar CEREBRAL HEMORRHAGE; cerebral ischemia (BRAIN ISCHEMIA); and CEREBRAL INFARCTION. Cerebral amyloid angiopathy is unrelated to generalized AMYLOIDOSIS. Amyloidogenic peptides in this condition are nearly always the same ones found in ALZHEIMER DISEASE. (from Kumar: Robbins and Cotran: Pathologic Basis of Disease, 7th ed., 2005)Craniotomy: Any operation on the cranium or incision into the cranium. (Dorland, 28th ed)Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Cerebrovascular Disorders: A spectrum of pathological conditions of impaired blood flow in the brain. They can involve vessels (ARTERIES or VEINS) in the CEREBRUM, the CEREBELLUM, and the BRAIN STEM. Major categories include INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; BRAIN ISCHEMIA; CEREBRAL HEMORRHAGE; and others.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Lung Diseases: Pathological processes involving any part of the LUNG.Neurosurgical Procedures: Surgery performed on the nervous system or its parts.Melena: The black, tarry, foul-smelling FECES that contain degraded blood.Warfarin: An anticoagulant that acts by inhibiting the synthesis of vitamin K-dependent coagulation factors. Warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. It is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. Warfarin is also used as a rodenticide.Esophageal and Gastric Varices: Dilated blood vessels in the ESOPHAGUS or GASTRIC FUNDUS that shunt blood from the portal circulation (PORTAL SYSTEM) to the systemic venous circulation. Often they are observed in individuals with portal hypertension (HYPERTENSION, PORTAL).HemosiderinInfant, Premature, DiseasesThrombolytic Therapy: Use of infusions of FIBRINOLYTIC AGENTS to destroy or dissolve thrombi in blood vessels or bypass grafts.Glasgow Outcome Scale: A scale that assesses the outcome of serious craniocerebral injuries, based on the level of regained social functioning.Infant, Newborn: An infant during the first month after birth.Resuscitation: The restoration to life or consciousness of one apparently dead. (Dorland, 27th ed)Hematemesis: Vomiting of blood that is either fresh bright red, or older "coffee-ground" in character. It generally indicates bleeding of the UPPER GASTROINTESTINAL TRACT.Oxytocics: Drugs that stimulate contraction of the myometrium. They are used to induce LABOR, OBSTETRIC at term, to prevent or control postpartum or postabortion hemorrhage, and to assess fetal status in high risk pregnancies. They may also be used alone or with other drugs to induce abortions (ABORTIFACIENTS). Oxytocics used clinically include the neurohypophyseal hormone OXYTOCIN and certain prostaglandins and ergot alkaloids. (From AMA Drug Evaluations, 1994, p1157)Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Intracranial Pressure: Pressure within the cranial cavity. It is influenced by brain mass, the circulatory system, CSF dynamics, and skull rigidity.Spinal Puncture: Tapping fluid from the subarachnoid space in the lumbar region, usually between the third and fourth lumbar vertebrae.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Hemostatic Techniques: Techniques for controlling bleeding.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Adrenal Gland Diseases: Pathological processes of the ADRENAL GLANDS.Intracranial Hypertension: Increased pressure within the cranial vault. This may result from several conditions, including HYDROCEPHALUS; BRAIN EDEMA; intracranial masses; severe systemic HYPERTENSION; PSEUDOTUMOR CEREBRI; and other disorders.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Blood Volume: Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.Recurrence: The return of a sign, symptom, or disease after a remission.Hematoma, Subdural, Intracranial: Accumulation of blood in the SUBDURAL SPACE over the CEREBRAL HEMISPHERE.Ischemic Attack, Transient: Brief reversible episodes of focal, nonconvulsive ischemic dysfunction of the brain having a duration of less than 24 hours, and usually less than one hour, caused by transient thrombotic or embolic blood vessel occlusion or stenosis. Events may be classified by arterial distribution, temporal pattern, or etiology (e.g., embolic vs. thrombotic). (From Adams et al., Principles of Neurology, 6th ed, pp814-6)Hemostatics: Agents acting to arrest the flow of blood. Absorbable hemostatics arrest bleeding either by the formation of an artificial clot or by providing a mechanical matrix that facilitates clotting when applied directly to the bleeding surface. These agents function more at the capillary level and are not effective at stemming arterial or venous bleeding under any significant intravascular pressure.Subarachnoid Space: The space between the arachnoid membrane and PIA MATER, filled with CEREBROSPINAL FLUID. It contains large blood vessels that supply the BRAIN and SPINAL CORD.Extravasation of Diagnostic and Therapeutic Materials: The escape of diagnostic or therapeutic material from the vessel into which it is introduced into the surrounding tissue or body cavity.Pituitary Apoplexy: The sudden loss of blood supply to the PITUITARY GLAND, leading to tissue NECROSIS and loss of function (PANHYPOPITUITARISM). The most common cause is hemorrhage or INFARCTION of a PITUITARY ADENOMA. It can also result from acute hemorrhage into SELLA TURCICA due to HEAD TRAUMA; INTRACRANIAL HYPERTENSION; or other acute effects of central nervous system hemorrhage. Clinical signs include severe HEADACHE; HYPOTENSION; bilateral visual disturbances; UNCONSCIOUSNESS; and COMA.Arteriovenous Malformations: Abnormal formation of blood vessels that shunt arterial blood directly into veins without passing through the CAPILLARIES. They usually are crooked, dilated, and with thick vessel walls. A common type is the congenital arteriovenous fistula. The lack of blood flow and oxygen in the capillaries can lead to tissue damage in the affected areas.Echoencephalography: Use of reflected ultrasound in the diagnosis of intracranial pathologic processes.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Hypotension: Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.Neurologic Examination: Assessment of sensory and motor responses and reflexes that is used to determine impairment of the nervous system.Labor Stage, Third: The final period of OBSTETRIC LABOR that is from the expulsion of the FETUS to the expulsion of the PLACENTA.Hemoptysis: Expectoration or spitting of blood originating from any part of the RESPIRATORY TRACT, usually from hemorrhage in the lung parenchyma (PULMONARY ALVEOLI) and the BRONCHIAL ARTERIES.Angiography: Radiography of blood vessels after injection of a contrast medium.Blood Coagulation Disorders: Hemorrhagic and thrombotic disorders that occur as a consequence of abnormalities in blood coagulation due to a variety of factors such as COAGULATION PROTEIN DISORDERS; BLOOD PLATELET DISORDERS; BLOOD PROTEIN DISORDERS or nutritional conditions.Antifibrinolytic Agents: Agents that prevent fibrinolysis or lysis of a blood clot or thrombus. Several endogenous antiplasmins are known. The drugs are used to control massive hemorrhage and in other coagulation disorders.Cranial Fossa, Posterior: The infratentorial compartment that contains the CEREBELLUM and BRAIN STEM. It is formed by the posterior third of the superior surface of the body of the sphenoid (SPHENOID BONE), by the occipital, the petrous, and mastoid portions of the TEMPORAL BONE, and the posterior inferior angle of the PARIETAL BONE.Ventriculoperitoneal Shunt: Surgical creation of a communication between a cerebral ventricle and the peritoneum by means of a plastic tube to permit drainage of cerebrospinal fluid for relief of hydrocephalus. (From Dorland, 28th ed)Angiography, Digital Subtraction: A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Cerebral Veins: Veins draining the cerebrum.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Coma: A profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused. Coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem RETICULAR FORMATION.Infant, Premature: A human infant born before 37 weeks of GESTATION.Headache: The symptom of PAIN in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of HEADACHE DISORDERS.Pons: The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.Surgical Instruments: Hand-held tools or implements used by health professionals for the performance of surgical tasks.Intracranial Thrombosis: Formation or presence of a blood clot (THROMBUS) in a blood vessel within the SKULL. Intracranial thrombosis can lead to thrombotic occlusions and BRAIN INFARCTION. The majority of the thrombotic occlusions are associated with ATHEROSCLEROSIS.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Hyphema: Bleeding in the anterior chamber of the eye.Factor VIIa: Activated form of factor VII. Factor VIIa activates factor X in the extrinsic pathway of blood coagulation.Leukomalacia, Periventricular: Degeneration of white matter adjacent to the CEREBRAL VENTRICLES following cerebral hypoxia or BRAIN ISCHEMIA in neonates. The condition primarily affects white matter in the perfusion zone between superficial and deep branches of the MIDDLE CEREBRAL ARTERY. Clinical manifestations include VISION DISORDERS; CEREBRAL PALSY; PARAPLEGIA; SEIZURES; and cognitive disorders. (From Adams et al., Principles of Neurology, 6th ed, p1021; Joynt, Clinical Neurology, 1997, Ch4, pp30-1)Brain Injuries: Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.Hemostasis, Surgical: Control of bleeding during or after surgery.Coagulants: Agents that cause clotting.Cisterna Magna: One of three principal openings in the SUBARACHNOID SPACE. They are also known as cerebellomedullary cistern, and collectively as cisterns.Blood Transfusion: The introduction of whole blood or blood component directly into the blood stream. (Dorland, 27th ed)International Normalized Ratio: System established by the World Health Organization and the International Committee on Thrombosis and Hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the International Sensitivity Index for the particular test reagent/instrument combination used.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Vitrectomy: Removal of the whole or part of the vitreous body in treating endophthalmitis, diabetic retinopathy, retinal detachment, intraocular foreign bodies, and some types of glaucoma.Hemostasis, Endoscopic: Control of bleeding performed through the channel of the endoscope. Techniques include use of lasers, heater probes, bipolar electrocoagulation, and local injection. Endoscopic hemostasis is commonly used to treat bleeding esophageal and gastrointestinal varices and ulcers.Hemostasis: The process which spontaneously arrests the flow of BLOOD from vessels carrying blood under pressure. It is accomplished by contraction of the vessels, adhesion and aggregation of formed blood elements (eg. ERYTHROCYTE AGGREGATION), and the process of BLOOD COAGULATION.Shock: A pathological condition manifested by failure to perfuse or oxygenate vital organs.Craniocerebral Trauma: Traumatic injuries involving the cranium and intracranial structures (i.e., BRAIN; CRANIAL NERVES; MENINGES; and other structures). Injuries may be classified by whether or not the skull is penetrated (i.e., penetrating vs. nonpenetrating) or whether there is an associated hemorrhage.Lateral Ventricles: Cavity in each of the CEREBRAL HEMISPHERES derived from the cavity of the embryonic NEURAL TUBE. They are separated from each other by the SEPTUM PELLUCIDUM, and each communicates with the THIRD VENTRICLE by the foramen of Monro, through which also the choroid plexuses (CHOROID PLEXUS) of the lateral ventricles become continuous with that of the third ventricle.Putamen: The largest and most lateral of the BASAL GANGLIA lying between the lateral medullary lamina of the GLOBUS PALLIDUS and the EXTERNAL CAPSULE. It is part of the neostriatum and forms part of the LENTIFORM NUCLEUS along with the GLOBUS PALLIDUS.Middle Cerebral Artery: The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.Hemoperitoneum: Accumulations of blood in the PERITONEAL CAVITY due to internal HEMORRHAGE.Mallory-Weiss Syndrome: A condition characterized by mucosal tears at the ESOPHAGOGASTRIC JUNCTION, sometimes with HEMATEMESIS. Typically it is caused by forceful bouts of retching or VOMITING.Epistaxis: Bleeding from the nose.Brain Diseases: Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.Intracranial Embolism and Thrombosis: Embolism or thrombosis involving blood vessels which supply intracranial structures. Emboli may originate from extracranial or intracranial sources. Thrombosis may occur in arterial or venous structures.Hypovolemia: An abnormally low volume of blood circulating through the body. It may result in hypovolemic shock (see SHOCK).Magnetic Resonance Angiography: Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.Maternal Mortality: Maternal deaths resulting from complications of pregnancy and childbirth in a given population.Consciousness Disorders: Organic mental disorders in which there is impairment of the ability to maintain awareness of self and environment and to respond to environmental stimuli. Dysfunction of the cerebral hemispheres or brain stem RETICULAR FORMATION may result in this condition.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Vertebral Artery: The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Fundus Oculi: The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)Moyamoya Disease: A noninflammatory, progressive occlusion of the intracranial CAROTID ARTERIES and the formation of netlike collateral arteries arising from the CIRCLE OF WILLIS. Cerebral angiogram shows the puff-of-smoke (moyamoya) collaterals at the base of the brain. It is characterized by endothelial HYPERPLASIA and FIBROSIS with thickening of arterial walls. This disease primarily affects children but can also occur in adults.Disseminated Intravascular Coagulation: A disorder characterized by procoagulant substances entering the general circulation causing a systemic thrombotic process. The activation of the clotting mechanism may arise from any of a number of disorders. A majority of the patients manifest skin lesions, sometimes leading to PURPURA FULMINANS.Tranexamic Acid: Antifibrinolytic hemostatic used in severe hemorrhage.Nimodipine: A calcium channel blockader with preferential cerebrovascular activity. It has marked cerebrovascular dilating effects and lowers blood pressure.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Platelet Aggregation Inhibitors: Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system.Hypertension, Portal: Abnormal increase of resistance to blood flow within the hepatic PORTAL SYSTEM, frequently seen in LIVER CIRRHOSIS and conditions with obstruction of the PORTAL VEIN.Hemosiderosis: Conditions in which there is a generalized increase in the iron stores of body tissues, particularly of liver and the MONONUCLEAR PHAGOCYTE SYSTEM, without demonstrable tissue damage. The name refers to the presence of stainable iron in the tissue in the form of hemosiderin.Vitreous Body: The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.Gestational Age: The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization.Drainage: The removal of fluids or discharges from the body, such as from a wound, sore, or cavity.Hemangioma, Cavernous: A vascular anomaly that is a collection of tortuous BLOOD VESSELS and connective tissue. This tumor-like mass with the large vascular space is filled with blood and usually appears as a strawberry-like lesion in the subcutaneous areas of the face, extremities, or other regions of the body including the central nervous system.Necrosis: The pathological process occurring in cells that are dying from irreparable injuries. It is caused by the progressive, uncontrolled action of degradative ENZYMES, leading to MITOCHONDRIAL SWELLING, nuclear flocculation, and cell lysis. It is distinct it from APOPTOSIS, which is a normal, regulated cellular process.Thromboembolism: Obstruction of a blood vessel (embolism) by a blood clot (THROMBUS) in the blood stream.Ultrasonography, Doppler, Transcranial: A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.Brain Damage, Chronic: A condition characterized by long-standing brain dysfunction or damage, usually of three months duration or longer. Potential etiologies include BRAIN INFARCTION; certain NEURODEGENERATIVE DISORDERS; CRANIOCEREBRAL TRAUMA; ANOXIA, BRAIN; ENCEPHALITIS; certain NEUROTOXICITY SYNDROMES; metabolic disorders (see BRAIN DISEASES, METABOLIC); and other conditions.Neuroendoscopy: PROCEDURES that use NEUROENDOSCOPES for disease diagnosis and treatment. Neuroendoscopy, generally an integration of the neuroendoscope with a computer-assisted NEURONAVIGATION system, provides guidance in NEUROSURGICAL PROCEDURES.Nervous System Diseases: Diseases of the central and peripheral nervous system. This includes disorders of the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscle.Hemangioma, Cavernous, Central Nervous System: A vascular anomaly composed of a collection of large, thin walled tortuous VEINS that can occur in any part of the central nervous system but lack intervening nervous tissue. Familial occurrence is common and has been associated with a number of genes mapped to 7q, 7p and 3q. Clinical features include SEIZURES; HEADACHE; STROKE; and progressive neurological deficit.Consciousness: Sense of awareness of self and of the environment.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Jejunal Diseases: Pathological development in the JEJUNUM region of the SMALL INTESTINE.Endoscopy: Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Infant, Newborn, Diseases: Diseases of newborn infants present at birth (congenital) or developing within the first month of birth. It does not include hereditary diseases not manifesting at birth or within the first 30 days of life nor does it include inborn errors of metabolism. Both HEREDITARY DISEASES and METABOLISM, INBORN ERRORS are available as general concepts.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Obstetric Labor Complications: Medical problems associated with OBSTETRIC LABOR, such as BREECH PRESENTATION; PREMATURE OBSTETRIC LABOR; HEMORRHAGE; or others. These complications can affect the well-being of the mother, the FETUS, or both.Aneurysm: Pathological outpouching or sac-like dilatation in the wall of any blood vessel (ARTERIES or VEINS) or the heart (HEART ANEURYSM). It indicates a thin and weakened area in the wall which may later rupture. Aneurysms are classified by location, etiology, or other characteristics.Iatrogenic Disease: Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment.Hematoma, Epidural, Cranial: Accumulation of blood in the EPIDURAL SPACE between the SKULL and the DURA MATER, often as a result of bleeding from the MENINGEAL ARTERIES associated with a temporal or parietal bone fracture. Epidural hematoma tends to expand rapidly, compressing the dura and underlying brain. Clinical features may include HEADACHE; VOMITING; HEMIPARESIS; and impaired mental function.Head Injuries, Closed: Traumatic injuries to the cranium where the integrity of the skull is not compromised and no bone fragments or other objects penetrate the skull and dura mater. This frequently results in mechanical injury being transmitted to intracranial structures which may produce traumatic brain injuries, hemorrhage, or cranial nerve injury. (From Rowland, Merritt's Textbook of Neurology, 9th ed, p417)Autopsy: Postmortem examination of the body.Delivery, Obstetric: Delivery of the FETUS and PLACENTA under the care of an obstetrician or a health worker. Obstetric deliveries may involve physical, psychological, medical, or surgical interventions.Hematoma, Epidural, Spinal: A rare epidural hematoma in the spinal epidural space, usually due to a vascular malformation (CENTRAL NERVOUS SYSTEM VASCULAR MALFORMATIONS) or TRAUMA. Spontaneous spinal epidural hematoma is a neurologic emergency due to a rapidly evolving compressive MYELOPATHY.Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Cesarean Section: Extraction of the FETUS by means of abdominal HYSTEROTOMY.Misoprostol: A synthetic analog of natural prostaglandin E1. It produces a dose-related inhibition of gastric acid and pepsin secretion, and enhances mucosal resistance to injury. It is an effective anti-ulcer agent and also has oxytocic properties.Neurosurgery: A surgical specialty concerned with the treatment of diseases and disorders of the brain, spinal cord, and peripheral and sympathetic nervous system.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Dura Mater: The outermost of the three MENINGES, a fibrous membrane of connective tissue that covers the brain and the spinal cord.Duodenal Diseases: Pathological conditions in the DUODENUM region of the small intestine (INTESTINE, SMALL).Headache Disorders, Primary: Conditions in which the primary symptom is HEADACHE and the headache cannot be attributed to any known causes.Injections, Intra-Arterial: Delivery of drugs into an artery.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Injections: Introduction of substances into the body using a needle and syringe.Endoscopy, Gastrointestinal: Endoscopic examination, therapy or surgery of the gastrointestinal tract.Blood Loss, Surgical: Loss of blood during a surgical procedure.Birth Injuries: Mechanical or anoxic trauma incurred by the infant during labor or delivery.Pregnancy Complications: Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.Survival Rate: The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.Pregnancy Complications, Cardiovascular: The co-occurrence of pregnancy and a cardiovascular disease. The disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.