Neurological damage is damage that's occurred to the nervous system, including the brain, spinal cord and nerves, whether through injury, infection or disease. This type of damage can cause problems with everything from moving and speaking to swallowing and breathing, as well as changes in memory, mood and sensory perception. But what do you know about pheochromocytomas? Or ataxia? There are more than 600 types of neurological disorders, but we're here to cover some you might not know about: five rare conditions that cause damage to your nervous system. Pheochromocytoma stimulates the release of excess catecholamines -- hormones including dopamine, adrenaline, metanephrine and noradrenaline the body uses to manage your heart rate, blood pressure, blood sugar and its response to stress. When your body feels stressed, it floods your bloodstream with catecholamines (fight or flight, remember?). When it's a tumor triggering the release of those hormones rather than your body's natural stress response, it can cause chronic, uncontrollable hypertension, headaches, heart palpitations and excessive sweating.

When a pheochromocytoma grows outside the adrenal glands it's called a paraganglioma. Agnosia is a condition where you are unable to properly perceive objects. It's the result of damage to the brain, usually in the occipital lobe (which is where the brain handles visual processing) or parietal lobes (where the brain processes peripheral sensory information). It affects how your brain is able to identify and perceive objects around you. For example, a person suffering from auditory agnosia may not be able to identify a sneeze based on its sound, but would have no trouble visually identifying a person who is sneezing. A person suffering from visual agnosia may not be able to distinguish the spoon in a set of flatware but has no problem with sense of taste. If you suffer from gustatory agnosia, you may not be able to identify your favorite culinary dish. And so on. This type of damage may result from a tumor, injury or degeneration, and may be caused by stroke, dementia, brain lesions, and other neurological problems and developmental conditions.

While most people will recover from agnosia within three months, it may take as much as a full year for the condition to resolve. Sometimes, visual agnosia gets broken down into two categories. When a person can't properly identify or differentiate shapes or objects, it's known as apperceptive agnosia. And when a person can't recognize or name an object despite understanding what the object is or is used for, it's categorized as associative agnosia. Paraneoplastic neurologic syndromes (PNS), also called paraneoplastic neurologic disorders, happen when the body's immune system has an abnormal response to a neoplasm, a cancerous tumor. The body's white blood cells -- antibodies the body uses to attack those cancer cells -- begin to attack normal, healthy cells in the nervous system while fighting the tumor. Batten disease is a rare genetic condition that's part of a group of progressive degenerative neurometabolic disorders known drugs and certain medications, as well as lead or mercury poisoning, may be to blame. Ataxia may also run in some families, a genetic condition where the body produces abnormal proteins that eventually cause nerve cells to degenerate. Auchus, Alexander. "Agnosia." The Merck Manual for Health Care Professionals. Batten Disease Support & Research Association. Genetic and Rare Diseases Information Center (GARD) - Office of Rare Diseases Research. Genetic and Rare Diseases Information Center (GARD) - Office of Rare Diseases Research. National Institute of Neurological Disorders and Stroke. National Institute of Neurological Disorders and Stroke. National Institute of Neurological Disorders and Stroke. National Institute of Neurological Disorders and Stroke. National Institutes of Health - Eunice Kennedy Shriver National Institute of Child Health & Human Development. National Organization for Rare Disorders.