Tension headache, also known as stress headache, or tension-type headache (TTH), is the most common type of primary headache. The pain can radiate from the lower back of the head, the neck, eyes or other muscle groups in the body typically affecting both sides of the head. Tension-type headaches account for nearly 90% of all headaches. Pain medications, such as paracetamol and ibuprofen, are effective for the treatment of tension headache. Tricyclic antidepressants appear to be useful for prevention. Evidence is poor for SSRIs, propranolol and muscle relaxants.As of 2016, tension headaches affect about 1.89 billion people and are more common in women than men (23% to 18% respectively). Signs and symptoms
According to the third edition of the International Classification of Headache Disorders, the attacks must meet the following criteria:

A duration of between 30 minutes and 7 days. At least two of the following four characteristics:
bilateral location
pressing or tightening (non-pulsating) quality
mild or moderate intensity
not aggravated by routine physical activity such as walking or climbing stairs
Both of the following:
no nausea or vomiting
no more than one of photophobia (sensitivity to bright light) or phonophobia (sensitivity to loud sounds)Tension-type headaches may be accompanied by tenderness of the scalp on manual pressure during an attack. Risk factors
Various precipitating factors may cause tension-type headaches in susceptible individuals:
Anxiety
Stress
Sleep problems
Young age
Poor health

Mechanism
Although the musculature of the head and neck and psychological factors such as stress may play a role in the overall pathophysiology of TTH, neither is currently believed to be the sole cause of the development of TTH.
The head becomes so enlarged that they eventually may be bedridden.About 80–90% of fetuses or newborn infants with spina bifida—often associated with meningocele or myelomeningocele—develop hydrocephalus. Acquired
This condition is acquired as a consequence of CNS infections, meningitis, brain tumors, head trauma, toxoplasmosis, or intracranial hemorrhage (subarachnoid or intraparenchymal), and is usually painful. Type
The cause of hydrocephalus is not known with certainty and is probably multifactorial. It may be caused by impaired CSF flow, reabsorption, or excessive CSF production. Obstruction to CSF flow hinders its free passage through the ventricular system and subarachnoid space (e.g., stenosis of the cerebral aqueduct or obstruction of the interventricular foramina secondary to tumors, hemorrhages, infections or congenital malformations) and can cause increases in ICP. Hydrocephalus can also be caused by overproduction of CSF (relative obstruction) (e.g., choroid plexus papilloma, villous hypertrophy). Bilateral ureteric obstruction is a rare, but reported, cause of hydrocephalus.Hydrocephalus can be classified into communicating and noncommunicating (obstructive). Both forms can be either congenital or acquired. Communicating
Communicating hydrocephalus, also known as nonobstructive hydrocephalus, is caused by impaired CSF reabsorption in the absence of any obstruction of CSF flow between the ventricles and subarachnoid space. This may be due to functional impairment of the arachnoidal granulations (also called arachnoid granulations or Pacchionis granulations), which are located along the superior sagittal sinus, and is the site of CSF reabsorption back into the venous system. Various neurologic conditions may result in communicating hydrocephalus, including subarachnoid/intraventricular hemorrhage, meningitis, and congenital absence of arachnoid villi.