In an intracranial, or cerebral, aneurysm, a weakness in the wall of a cerebral artery causes localized dilation. Cerebral aneurysms…

Brain tumors are abnormal growths that develop after transformation of cells within the brain, cerebral vasculature, or meninges. They’re usually…

Arteriovenous malformations (AVMs) are tangled masses of thin-walled, dilated blood vessels between arteries and veins that aren’t connected by capillaries.…

Commonly called Lou Gehrig’s disease, after the New York Yankees first baseman who died of this disorder, amyotrophic lateral sclerosis…

Alzheimer’s disease is a progressive degenerative disorder of the cerebral cortex, especially the frontal lobe. It affects approximately 4 million…

Acceleration-deceleration cervical injuries (commonly known as whiplash) result from sharp hyperextension and flexion of the neck that damages muscles, ligaments,…

Upper respiratory tract infection (also known as the common cold or acute coryza) is an acute, usually afebrile viral infection…

An acute or chronic infection caused by Mycobacterium tuberculosis, tuberculosis (TB) is characterized by pulmonary infiltrates, formation of granulomas with…

Severe acute respiratory syndrome (SARS) is a serious form of pneumonia, resulting in acute respiratory distress and, in some cases,…

Sarcoidosis is a multisystem, granulomatous disorder that characteristically produces lymphadenopathy, pulmonary infiltration, and skeletal, liver, eye, or skin lesions. Causes…