Medicines for Chiari malformation

What it is

A Chiari malformation is a condition in which the lower part of the brain — specifically the cerebellum (the part that coordinates movement), or part of it (the cerebellar tonsils) — extends down further than normal, through the opening at the base of the skull and into the top of the spinal canal. This is usually because the space at the back of the skull is smaller than usual or shaped differently, so the brain tissue is pushed down. There are different types, of varying severity; the most common type (type 1) is often present from birth (though the brain structure), but may not cause symptoms until later in life, if at all, while other, rarer types are more significant and usually diagnosed in babies or children. A key point about Chiari malformation (particularly the common type 1) is that many people have it without any symptoms — it is often discovered by chance on a brain scan done for another reason, and in many cases it never causes problems. When a Chiari malformation does cause symptoms, this is usually because the extending brain tissue affects the surrounding structures or the flow of the fluid around the brain and spinal cord. The most common symptom is a headache — characteristically felt at the back of the head, and often brought on or worsened by things that increase pressure, such as coughing, sneezing, straining, or physical exertion. Other symptoms can include neck pain, dizziness, balance problems, problems with swallowing or speech, numbness or tingling, weakness, visual disturbances, or, in some cases, other neurological symptoms; occasionally, a Chiari malformation can be associated with a build-up of fluid within the spinal cord (syringomyelia) or the brain (hydrocephalus), which can cause additional symptoms. Because many Chiari malformations cause no symptoms, and because treatment (surgery) has its own risks, management is individualised: many are simply monitored, particularly if they cause no or few symptoms; while surgery to create more space and relieve the pressure is considered in certain cases — for example, if there are significant symptoms, or associated problems such as syringomyelia. The key messages are that a Chiari malformation is where the lower part of the brain extends into the spinal canal, that it often causes no symptoms (and is frequently found by chance), and that it is managed by monitoring, with surgery considered in certain cases.

How it is treated

Chiari malformations are managed with individualised decisions — often monitoring for those causing no or few symptoms, and surgery in certain cases with significant symptoms or associated problems — based on the symptoms and situation, and guided by specialists. Chiari malformations are often found incidentally on a brain scan, or diagnosed when they cause symptoms; imaging (particularly MRI, which shows the malformation and can assess the surrounding structures and any associated problems such as syringomyelia or hydrocephalus) confirms the diagnosis and guides management. Because many Chiari malformations (especially the common type 1) cause no symptoms, and because surgery carries its own risks, decisions about management are made carefully and individually, weighing the symptoms and situation against the risks of treatment, with specialist (neurology and neurosurgery) input. For Chiari malformations that cause no symptoms, or only minor ones, the approach is often monitoring (observation) — which may include periodic scans and being alert to any new or worsening symptoms — without active treatment, as many such malformations do not cause problems. Managing symptoms is part of care where they occur — for example, managing headaches and other symptoms with appropriate measures. Surgery is considered in certain situations — particularly if there are significant or troublesome symptoms (such as severe or disabling headaches, or neurological symptoms) that are attributable to the malformation, or if there are associated problems such as syringomyelia (fluid in the spinal cord) or hydrocephalus (fluid on the brain) that need treatment. The main surgical treatment aims to create more space at the back of the skull and relieve the pressure on the brain tissue and improve the flow of the fluid around the brain and spinal cord (decompression surgery); other procedures may be used for associated problems (such as treating hydrocephalus). The decision to operate is individual and made carefully with the specialist team, weighing the potential benefits against the risks, as surgery is not always needed or beneficial, particularly for mild or symptomless cases. Being aware of and reporting new or worsening symptoms is important, so they can be assessed. For the rarer, more significant types (usually in babies and children), specialist care is provided, often including surgery and management of associated conditions. The reassuring messages are that many Chiari malformations cause no symptoms and never cause problems (and are often found by chance), that management is carefully individualised (often monitoring, with symptom management where needed), and that surgery is considered and can help in cases with significant symptoms or associated problems; so specialist assessment and individualised decisions are the keys to managing a Chiari malformation.