Signs and Symptoms of Subarachnoid Hemorrhage: What You Need to Know

Subarachnoid hemorrhage (SAH) is a life-threatening type of stroke that occurs when bleeding happens in the space between the brain and the surrounding membrane. One of the most characteristic features of this condition is its sudden onset. Patients often experience an intense headache that peaks within seconds to minutes, sometimes described as "the worst headache of their life." This abrupt symptom allows many individuals to recall the exact moment and circumstances of their attack with striking clarity.

Common Triggers and Initial Symptoms

Sudden emotional stress, strenuous physical activity, straining during bowel movements, heavy lifting, or even violent coughing can act as common triggers for SAH. The resulting headache is typically severe—described as throbbing, explosive, or splitting in nature—and may be localized to one area of the head or affect the entire skull. Unlike typical migraines or tension headaches, this pain does not subside with rest or over-the-counter medication and often worsens progressively.

Neurological and Systemic Manifestations

In addition to excruciating head pain, patients frequently develop nausea and vomiting due to increased intracranial pressure. Altered mental status is also common, ranging from confusion and agitation to deep coma. Some individuals may exhibit delirium, hallucinations, or other psychiatric disturbances, particularly among older adults who might initially present with behavioral changes rather than classic neurological signs.

A smaller subset of patients may experience seizures—either focal or generalized—at the onset of bleeding. Dizziness and vertigo are less common but possible early indicators, especially when the hemorrhage affects certain regions of the brain. Cranial nerve involvement, such as oculomotor nerve palsy leading to double vision or drooping eyelids, can also occur. Other focal deficits like mild hemiparesis, speech difficulties (aphasia), or sensory impairments may mimic ischemic stroke, making accurate diagnosis critical.

Major Complications of Subarachnoid Hemorrhage

One of the most dangerous aspects of SAH is the risk of rebleeding, which carries a staggering 50% mortality rate. The highest danger occurs within the first 24 hours after the initial bleed, although the risk remains elevated for up to four weeks. Factors associated with increased likelihood of rehemorrhage include loss of consciousness upon hospital admission, female sex, and systolic blood pressure exceeding 170 mmHg at presentation.

Secondary Neurological and Systemic Issues

Beyond rebleeding, several serious complications can follow SAH:

Cerebral vasospasm: Narrowing of brain arteries usually develops 3–14 days post-bleed, potentially causing delayed cerebral ischemia and infarction.
Hydrocephalus: Accumulation of cerebrospinal fluid due to impaired drainage may require shunting or external ventricular drainage.
Hyponatremia: Often caused by syndrome of inappropriate antidiuretic hormone secretion (SIADH) or cerebral salt-wasting syndrome, requiring careful electrolyte management.
Cardiac complications: ECG abnormalities, arrhythmias, and myocardial injury can occur due to neurogenic stress on the heart.
Pulmonary edema: Neurogenic pulmonary edema may develop rapidly, especially in severely affected patients.

Early recognition of subarachnoid hemorrhage symptoms is crucial for timely intervention and improved outcomes. Because the clinical picture can vary widely—from thunderclap headaches to subtle cognitive changes—it's essential for both healthcare providers and the public to remain vigilant. Prompt imaging, such as non-contrast CT scans or lumbar puncture when needed, plays a key role in confirming the diagnosis and guiding treatment strategies aimed at preventing secondary damage and reducing long-term disability.