Headache/seizure. Most people with brain tumors will have headaches that can be severe and associated with exam changes such as weakness or speech problems. Others can present with new onset seizures so anyone with a new seizure should be evaluated with a head ct/mri. Some brain tumors are benign but the aggressive tumors are called brain cancers usually glioblastoma. These must be followed after surgery/radiation.
Epileptic seizures. Seizures when present are the earliest and most important red flag that a brain tumor may be present. Epileptic seizures are not necessarily a convulsive seizure, but can be strange feeling like "deja-vu" "out of body feelings" "bad odors" or lapses of consciousness staring into space. Mri scanning is the key to detecting brain tumors, which can be benign or malignant.
The symptoms of Brain cancer include: Headache, Nausea, Vomiting, Double vision, Hearing loss, Papilledema.
Seizures, stroke. Probably the worst symptoms of any brain cancer are seizures, and a stroke-like onset. Seizures can be caused by stimulation of excitatory, or loss of inhibitory cortical circuits by the tumor. Stroke symptoms/onset can be due to hemorrhage into the tumor. Other symptoms include focal heurological deficit, like vision changes, headache from focal irritation of pain sensitive areas (lying down).
Too many to list. There are many symptoms of a brain tumor but I really dislike listing them---too many people have some of them due to far moer common causes--but believe they now have a brain tumor and panic. I believe that if your health is not right----for whatever signs or symptoms you have, you should see your primary care physician who is best capable of deciding what is the best path to follow.
Confusion, Dizziness, memory loss, slurred speech, loss of balance, weakness on one side of the body, seizures or blurred or double vision could signal a stroke or brain tumor, so always demand prompt medical action in those circumstances. Isolated headache is rarely caused by brain tumors.
Brain tumors in. Children are most common in the posterior fossa (cerebellum), and cause pressure leding to vomiting and head ache. Kids can also become clummsy, and sometimes bang their heads in pain. If old enough to walk, may stop walking, stagger, limp, nd change handedness, or neglect one side. Fortunately, children brain tumors are more curable than adults.
Too many to list. See the prior answer regarding symptoms of brain tumors--my approach is the same for kids or adults--if you have a health concern you should see your primary care physician--or bring your child to their physician. Lists of symptoms and signs do not help--they merely fuel panic.
Variable. The large majority present with either seizures, headache or personality change.
Vraiable. Headaches, blurred vision, facial or one sided body weakness, or any other non specific symptoms.
Unlikely. There are many causes of hearing a "sloshing" sound. I would start with a visit to your primary care physician before embarking on a brain tumor search. A brain tumor is very unlikely to be responsible--though it is remotely possible.
Many. Balance disturbance, gait changes, vision changes, new onset headache, personality, mood changes, memor changes, unexplaunable decline in behavior or school performance all warrant evaluation.
Many possibilities. I am very reluctant to suggest a list of symptoms that are associated with any disease, including a brain tumor. Although the use of warning symptoms and signs has its place in medicine, it is not a very helpful approach for brain tumors--since so many of the symptoms are more commonly associated with other causes. I would suggest you discuss any specific concerns with your teenager's doctor.