Post-concussion syndrome

Post-concussion syndrome, or PCS, is a set of symptoms that a person may experience for weeks, months, or even years after a concussion, a mild form of traumatic brain injury. As many as 50% of patients who have experienced concussion have PCS (Bazarian 1992), and some sources say as many as 90% of patients experience postconcussion symptoms (Legome, 2004).

Signs and symptoms

People who have had concussions may experience physical, mental, or emotional symptoms.

Physical symptoms can include:

headache
sensitivity to noise or light
dizziness
fatigue or sleepiness
inability to sleep
nausea and/or vomiting
double or blurred vision (Shepherd, 2004)
ringing in the ears
decreased sense of taste, smell, or hearing
decreased libido (UCLA, 1999)

Emotional symptoms may include:

irritability
anxiety (Evans, 1992)
restlessness (King, 2003)
depression or lack of emotion (Merck, 2003)
emotional lability or mood swings

Cognitive or mental symptoms can include:

amnesia or difficulty remembering things
confusion or impaired cognition (Evans, 1992)
difficulty with abstract thinking (King, 2003)
difficulty concentrating (UCLA, 1999)

Treatment

Patients who have suffered a head injury must be examined by emergency medical care providers to ensure that the head injury is not worse than concussion and potentially life threatening. Thus, head injury patients with symptoms that may indicate a dangerous injury are given CT scans or MRIs and are observed by medical staff. Later, the patient may be tested to determine his or her level of cognitive functioning. A test called the Rivermead Postconcussion Symptoms Questionnaire exists to measure the severity of the patient's symptoms.

Post-concussion syndrome is usually not treated, except with pain relievers for headaches and medicine to relieve depression, nausea, or dizziness (Merck, 2003). When patients have ongoing disabilities, they are treated with therapy to help them function at work, socially, or in other contexts (Shepherd, 2004). Patients are aided in gradually returning to work and other preinjury activities as symptoms permit. Since stress exacerbates post concussion symptoms, and vice versa, an important part of treatment is letting the patient know that symptoms are normal and helping the patient deal with impairments (King, 2003).

Prognosis

For most patients, post concussion symptoms go away within a few days to several weeks after the original injury occurs (Merck, 2003). In others, symptoms may remain for three to six months (Evans, 1992; UCLA, 1999). In a small percentage of patients, symptoms may persist for years or may be permanent (UCLA, 1999). If symptoms are not resolved by one year, they are likely to be permanent (Legome, 2004). However, the prognosis for PCS is generally considered excellent, with total resolution of symptoms in the large majority of cases.

If a patient receives another blow to the head after a concussion but before concussion symptoms have gone away, there is a slight risk that he or she will develop the very rare but deadly Second Impact Syndrome (SIS). In SIS, the brain may rapidly swell and be damaged.

Epidemiology

The incidence of PCS is higher in females than in males (Legome, 2004). People over the age of 55 are more likely to have long-lasting symptoms ^*. Since PCS by definition only exists in people who have suffered a head injury, demographics and risk factors are similar to those for head injury; for example, young adults are at higher risk than others for receiving head injury (Legome, 2004).

History

People have known about post-concussion syndrome for hundreds of years (Evans, 1992). Since it is not always possible to find a physical basis for the syndrome, some have claimed that patients are merely malingering or overreacting. It is not known to exactly what degree the symptoms are due to microscopic damage to the brain or to other factors, for example psychological factors (Merck, 2003). This question has been heavily debated for many years. Psychological factors are known to affect post concussion symptoms; however, it has been shown that structural damage does occur after some concussions (Evans, 1992, King, 2003).

In the 1860s, a group of doctors began to support the idea that structural features were to blame for symptoms, but the prevailing sentiment was still that psychological factors caused PCS (Fisher, 1998). It was not until a century later, in the 1960s, that such structural damage could be visualized using new brain scanning technology. Now it is generally agreed that PCS does have a physical basis.

The name "post-concussive syndrome" was first coined by S. H. Auerbach ^*.

References

Bazarian JJ and Atabaki S. 2001. Predicting postconcussion syndrome after minor traumatic brain injury. Academic Emergency Medicine Volume 8, Number 8, 788-795.
Evans RW . 1992. The postconcussion syndrome and the sequelae of mild head injury. Neurol Clin Volume 10 Number 4, 815-847.
Fisher JD. 1998. Post concussion syndrome. Head Injury Hotline.
King NS. 2003. Post-concussion syndrome: clarity amid the controversy?
Legome E. 2004. Postconcussive syndrome. eMedicine.com.
Merck manuals online medical library. 2003. Concussion.
Shepherd S. 2004. Head trauma. eMedicine.com.
Tolias C and Sgouros S. 2003. Initial evaluation and management of CNS injury."
UCLA Neurosurgery. 1999. Brain injury diseases and disorders: Concussion.