Brain Bleeds & Clots

Intracranial bleeding and abnormal clot formation represent two of the most time-sensitive emergencies in neurology and critical care. Whether occurring spontaneously, as a complication of a brain tumor, or following trauma, a stroke, or a blood-clotting disorder, the ability of blood to accumulate where it does not belong — inside or around the brain — can rapidly escalate into life-threatening neurological compromise. This section covers the spectrum of brain bleeds and blood clots: how to recognize them early, how clinicians treat them, and how conditions such as hydrocephalus and hyponatremia complicate the recovery journey.

Hemorrhage vs. Brain Bleed: Defining the Terms

The terms "brain bleed" and "hemorrhage" are often used interchangeably, but they carry slightly different clinical weight. A hemorrhage refers specifically to the escape of blood from a ruptured vessel — it is the act of bleeding, and can occur anywhere in the body. An intracranial hemorrhage (ICH) is a hemorrhage that occurs within the skull, encompassing all forms of bleeding inside or around the brain. A brain bleed is a colloquial term for the same phenomenon, typically referring to blood accumulating in the brain tissue itself or in the spaces surrounding it. The critical distinction lies in location: different compartments of the skull produce very different clinical pictures, and the treatment approach depends heavily on where exactly the blood has collected. As detailed in a landmark 2023 review in Frontiers in Neurology, intracranial hemorrhage accounts for 10–15% of all strokes worldwide, yet carries a disproportionately high mortality and morbidity burden relative to ischemic stroke.

Source: Cerebral Hemorrhage: Pathophysiology, Treatment, and Future Directions — Frontiers in Neurology, PubMed Central 2023

Types of Intracranial Hemorrhage

Early Warning Signs: When a Tumor May Be Bleeding

For patients with a known brain tumor, recognizing the early signs of intratumoral hemorrhage is critical, because what may initially appear to be disease progression can in fact be an acute bleed requiring emergency intervention. The most common warning signs include a sudden and dramatic worsening of existing headache — often described as the "worst headache of my life" — as well as rapid onset or worsening of focal neurological deficits (arm weakness, facial drooping, aphasia), a new or markedly increased seizure burden, sudden confusion or altered level of consciousness, unexplained nausea and vomiting, and new visual disturbances. Any of these changes, particularly when they occur acutely rather than gradually, should prompt immediate neuroimaging. A non-contrast CT scan is the fastest first-line tool to identify acute hemorrhage, which appears as a hyperdense (bright white) region, while MRI with susceptibility-weighted imaging (SWI) is more sensitive for detecting small amounts of old or acute blood, including microhemorrhages that CT may miss.

Emergency Response: What the ER Team Does

When a patient arrives in the emergency department with signs of intracranial hemorrhage, the team moves rapidly through a structured protocol. Immediate priorities include airway protection (with intubation if the patient cannot protect their airway or has a Glasgow Coma Scale score below 8), blood pressure management (acute hypertension accelerates hematoma expansion and must be controlled carefully — typically to a systolic below 140 mmHg for ICH), reversal of anticoagulation if applicable, and urgent neuroimaging to define the location, size, and trajectory of the bleed.

Once the hemorrhage is identified, the neurosurgical team is activated. Key emergency procedures include:

External Ventricular Drains (EVDs)

An external ventricular drain (EVD) is a catheter inserted through a burr hole in the skull, passed through brain tissue, and positioned within one of the lateral ventricles — fluid-filled chambers at the center of the brain. Once in place, the EVD allows continuous drainage of cerebrospinal fluid (CSF), which serves two critical purposes: it relieves elevated intracranial pressure (ICP) by diverting CSF away from the brain, and it can allow simultaneous ICP monitoring via a pressure transducer connected to the catheter. EVDs are standard of care for patients with intraventricular hemorrhage (IVH), severe subarachnoid hemorrhage with hydrocephalus, and any hemorrhage causing obstructive hydrocephalus with elevated ICP. The drain is managed by the ICU nursing team, who monitor ICP continuously and adjust the drainage level according to neurosurgical orders. Key complications include infection (ventriculitis), over-drainage causing brain herniation, catheter obstruction (particularly from blood clot), and catheter malpositioning. EVDs are typically temporary — once the underlying pathology has resolved or stabilized, the team performs a "clamping trial" to assess whether the patient can manage without CSF diversion before the catheter is removed.

In some cases involving skull base hemorrhages or posterior fossa bleeds where ventricular access is difficult, direct drainage of blood from the operative site is performed via suboccipital or retrosigmoid approaches. Lumbar drains — placed in the lower spinal canal — are also used in subarachnoid hemorrhage to drain bloody CSF and reduce the risk of vasospasm and hydrocephalus.

Blood Clots: Definition and Types

A blood clot (thrombus) is a semi-solid mass of platelets and fibrin that forms within a blood vessel in response to injury or, pathologically, in the absence of injury. While clotting is an essential protective mechanism against blood loss, clots that form inappropriately or travel through the bloodstream (becoming emboli) can cause life-threatening obstruction of blood flow to critical organs. The type and severity of disease depends on where the clot forms or lodges.

A 2025 survey by the International Society for Thrombosis and Haemostasis (ISTH) revealed that the management of blood clots remains highly inconsistent across clinical settings, even among patients with identical risk profiles — underscoring the need for standardized, evidence-based care pathways and the value of patient advocacy in understanding one's own treatment options.

Source: New Survey Shows Management of Blood Clots is Inconsistent, Even for Patients with Same Risk Profile — ISTH, 2025

Causes and Risk Factors

Brain bleeds and pathological clots share many underlying causes. Hypertension is the single most common cause of spontaneous ICH, responsible for approximately 50% of cases — chronic uncontrolled high blood pressure weakens small penetrating arteries deep within the brain (particularly the basal ganglia, thalamus, pons, and cerebellum), eventually causing them to rupture. Cerebral amyloid angiopathy (CAA) — the deposition of amyloid protein in cortical blood vessel walls — is the leading cause of lobar ICH in older adults and is associated with multiple and recurrent bleeds. Anticoagulant and antiplatelet medications (warfarin, heparin, direct oral anticoagulants such as apixaban and rivaroxaban, aspirin, clopidogrel) are a rapidly growing cause of ICH, particularly as the aging population increasingly relies on them for atrial fibrillation and venous thromboembolism prophylaxis. Coagulopathies — whether inherited (hemophilia, von Willebrand disease) or acquired (liver disease, disseminated intravascular coagulation) — impair the clotting cascade and predispose to spontaneous bleeding. Vascular malformations (arteriovenous malformations, cavernous malformations, dural AV fistulas) represent structural abnormalities of the cerebral vasculature that carry significant lifetime bleeding risk. Venous thromboembolism risk is heightened by immobility, malignancy, inherited thrombophilias (Factor V Leiden, Prothrombin G20210A mutation, Protein C or S deficiency, antiphospholipid syndrome), oral contraceptive use, pregnancy, and dehydration. Emerging evidence also links COVID-19 infection with a hypercoagulable state that increases the risk of both venous and arterial thrombosis, including pulmonary embolism.

Source: Long COVID and Wavering Incidence of Pulmonary Embolism: A Systematic Review — Journal of Community Hospital Internal Medicine Perspectives, PubMed Central 2023

Identifying and Treating a Brain Bleed

The management of intracranial hemorrhage is one of the most complex and time-pressured decision trees in all of medicine. Every minute matters — hematoma volume can double within the first hour, and each 10% increase in hematoma size is associated with a meaningful worsening of neurological outcome. The following is the step-by-step protocol used by ICU and neurosurgical teams when a patient with a suspected brain bleed enters the hospital.

The Risks and Benefits of Clot Removal

Surgical clot removal is not a universal solution — it is a high-stakes decision made case by case, weighing the probability of benefit against a real and serious risk profile. The STICH trial found no overall benefit of early craniotomy over conservative management in spontaneous supratentorial ICH; however, subgroup analyses suggested benefit for superficial lobar hematomas within 1 cm of the cortical surface. Cerebellar hematomas > 3 cm are generally a surgical emergency. Aneurysmal SAH is treated with clipping or endovascular coiling (ISAT trial showed coiling superior for most anterior circulation aneurysms).

Hydrocephalus: A Common and Dangerous Complication

Hydrocephalus — literally "water on the brain" — refers to the pathological accumulation of cerebrospinal fluid (CSF) within the ventricular system of the brain, causing the ventricles to expand and the brain to be compressed against the rigid skull. CSF is normally produced by the choroid plexus within the lateral ventricles, circulates through the ventricular system and subarachnoid space, and is absorbed by arachnoid granulations along the superior sagittal sinus. Hydrocephalus occurs when this delicate balance is disrupted — either by obstruction of CSF flow (obstructive or non-communicating hydrocephalus), impaired CSF absorption (communicating hydrocephalus), or, rarely, overproduction of CSF (as in choroid plexus tumors).

In the context of brain bleeds, hydrocephalus is a common and dangerous secondary complication. Blood entering the ventricular system (IVH) can obstruct the narrow passages within the brain — particularly the Sylvian aqueduct and the foramina of Luschka and Magendie — causing acute obstructive hydrocephalus within hours. Blood in the subarachnoid space (SAH) can impair arachnoid granulation function and produce communicating hydrocephalus days to weeks after the initial hemorrhage. Untreated hydrocephalus causes progressive elevation of intracranial pressure, which first produces the classic triad of headache, nausea/vomiting, and papilledema (swelling of the optic disc visible on fundoscopy), and can then progress to Cushing's triad (bradycardia, hypertension, irregular respirations), herniation, and death. In pediatric patients, whose skulls have not yet fused, hydrocephalus also causes macrocephaly (abnormally large head circumference) and a characteristic "setting sun sign" — downward deviation of the eyes due to pressure on the midbrain tectum.

Hyponatremia: The Hidden Danger in Brain Injury

Hyponatremia — a serum sodium concentration below 135 mEq/L — is one of the most common and under-recognized electrolyte disturbances in patients with brain bleeds, brain tumors, and neurosurgical disease. It occurs in up to 50% of patients following subarachnoid hemorrhage, and its presence is associated with significantly worse neurological outcomes, longer ICU stays, and higher in-hospital mortality. In the setting of intracranial pathology, hyponatremia typically arises through two distinct mechanisms that are frequently confused with each other: Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH), in which excess ADH causes water retention and dilutional sodium fall, and Cerebral Salt Wasting (CSW), in which the injured brain signals the kidneys to excrete excessive sodium, leading to volume depletion and a true sodium deficit. Correctly distinguishing between SIADH and CSW is not merely academic — the treatments are opposite: SIADH is managed with fluid restriction, while CSW requires aggressive sodium and fluid replacement. Misidentifying CSW as SIADH and fluid-restricting a volume-depleted SAH patient can precipitate cerebral vasospasm, a devastating secondary ischemic injury.

Hyponatremia also has a complex bidirectional relationship with hydrocephalus. As reviewed in a 2022 PubMed analysis of hydrocephalus-associated hyponatremia, the two conditions frequently co-occur and mutually exacerbate one another — elevated ICP can stimulate hypothalamic ADH release, and hyponatremia-induced cerebral edema can worsen intracranial hypertension. Treatment requires meticulous electrolyte monitoring, targeted sodium replacement using hypertonic saline (3% NaCl) for severe or symptomatic hyponatremia (targeting correction rates of no more than 8–10 mEq/L in any 24-hour period to avoid osmotic demyelination syndrome), and, when applicable, pharmacological targeting of the underlying hormonal dysregulation.

Sources: Hydrocephalus-Associated Hyponatremia: A Review — PubMed 2022 · A Study of Hyponatremia in Patients with Subarachnoid Hemorrhage — European Journal of Cardiovascular Medicine, 2025

Research & Additional References