Post-concussion Syndrome

Does one of the diagnostic criterion do patients a disservice?

Posted Mar 18, 2019

An excellent review of diagnostic issues related to mild traumatic brain injury (mTBI) and post-concussion syndrome (PCS) can be found in McCrea (2008). He clearly breaks down the various diagnostic systems that are currently used for head injuries.

The American Congress of Rehabilitation Medicine (ACRM) developed one of the most accepted diagnostic criteria for mild traumatic brain injury (mTBI). The criterion states that a person must have experienced a traumatically induced disruption of brain function manifested by at least one of the following: 1. Any period of loss of consciousness 2. Any loss of memory for events immediately before or after the accident 3. Any alteration in mental state at the time of the accident, for example, being dazed, disoriented, or confused 4. Focal neurological deficits that may or may not be transient. 

For a diagnosis of mild TBI, there were three additional ACRM criteria regarding the level of severity: 1. Loss of consciousness (LOC) cannot exceed 30 minutes. 2. After 30 minutes the Glasgow Coma Scale (GCS) score must range between 13 and 15. 3. Posttraumatic amnesia cannot be greater than 24 hours.

From a clinical perspective, the ACRM criteria appear to be sound. In contrast, the International Classification of Diseases, 10th Edition (ICD-10) criteria for post-concussion syndrome, in my opinion, misses the mark by its final criterion, which calls into question the validity of the patient’s complaints. It states that there is a preoccupation with symptoms of headache, dizziness, malaise, fatigue, noise intolerance, irritability, depression, anxiety, emotional lability, subjective concentration, memory, or intellectual difficulties without neuropsychological evidence of marked impairment, insomnia, and reduced alcohol tolerance. This specific final criterion that I believe is misguided states, “Preoccupation with above symptoms and fear of brain damage with hypochondriacal concern and adoption of the sick role” (McCrea, 2008). 

In my practice patients who have experienced brain trauma typically have most of the above symptoms, however, there usually is neuropsychological evidence of marked impairment. While it is possible that there may be hypochondriacal concerns, this is not common. Instead, these symptoms are entirely consistent with posttraumatic brain injury presentation in many car accidents and blast exposure patients I see.

From what we are learning about the possibility of pituitary and other endocrine dysfunction and the role of neuroinflammation from brain trauma, it may be doing a great disservice to patients to describe injured people’s concerns as hypochondriacal when in fact they may have hypopituitarism or another hormonal dysregulation. Hormonal dysregulation and neuroinflammatory responses are known to produce many of the symptoms reported in the ICD-10 and which are common to TBI patients. Research studies are increasingly showing the relationship between blast concussion and a high frequency of pituitary dysfunction (C. Wilkinson, et. al., 2012). See also the work of Gordon (2017, 2016).

In a personal communication, Dr. Gordon reminded me that neuroinflammation as the precipitating factor to global dysfunction of brain physiology needs to be highlighted. This is because studies on Cytokines (inflammatory proteins) are showing the association with all neuropsychiatric conditions ascribed to TBI/PTSD. He cautioned that treating pituitary dysfunction in isolation may not address the central problem which is neuroinflammation. Gordon further indicated that some hormonal deficiencies may be due to disruption of the enzymatic systems that produce hormones without there being damage to the pituitary.

I do not know what if any modifications will be in the ICD-11 edition slated to be presented at the World Health Assembly in May 2019 for adoption by member states, but I hope this last criterion is modified as it does a disservice to TBI patients.


Gordon, M.L. (2007) The Clinical Application of Interventional Endocrinology.  Phoenix Books: Beverly Hills, CA.

Gordon, M.L. (2016) Traumatic Brain Injury.  A Clinical Approach to Diagnosis and Treatment.

Kay T, Harrington, DE, Adams, R. et al. Definition of mild traumatic brain injury. J. Head Trauma Rehabil 1993: 8(3): 86-87.

McCrea, Michael A. (2008) Mild Traumatic Brain Injury and Postconcussion Syndrome.  New York: Oxford University Press.

Wilkinson, C, Pagulayan, K., Colasurdo, E., Shofer, J., & Peskind (2012).  Endocrine Abstracts, 29, P 1436.