In neurology and neurosurgery, the Monro-Kellie doctrine establishes relationships among brain, blood, and cerebrospinal fluid (CSF) volumes within a skull’s rigid confines. Any increase or decrease in one of these components must be counterbalanced with an increase or decrease in one or both other components to maintain a stable intracranial pressure (ICP) in the brain

Increased intracranial pressure (IICP) is a serious clinical issue that requires rapid assessment and intervention Decreased ICP, a less serious clinical issue (but still in need of treatment), may be due to dehydration, CSF leak, hemorrhage, or brain atrophy

increased intracranial pressure (IICP) — increase in intracranial pressure that occurs as a result of factors such as changes to blood volume, changes in the rates of CSF production and absorption, fluctuations in brain…. brain atrophy — loss of neurons and synapses sometimes caused by disorders such as MND, infections, and cerebral palsy. intracranial pressure (ICP) — pressure within the rigid confines of a skull in which brain tissue, blood, and CSF exist together. Monro-Kellie doctrine — principle that intracranial volume remains constant while within rigid skull constraints.