Neurological Comorbidities

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Neurological Comorbidities and Hypothalamic Hamartomas (HH)

Probably the most studied comorbidity associated with hypothalamic hamartomas (HH) is epilepsy. For many individuals with HH, it is intractable epilepsy – uncontrolled seizures that are frequent and drug-resistant. Most often, the HH associated epilepsy starts with gelastic (laughing) seizures or dacrystic (crying) seizures at a very early age – for some they begin at birth. However, since both laughing and crying are a part of normal behavior in infants and young children – these seizures often go undiagnosed until another more well-recognized seizure type develops. Many families spend years trying to capture this “unusual” behavior on video. However, gelastic and dacrystic seizures can be very difficult to capture – especially if they are somewhat infrequent and fleeting in duration. Some individuals with HH and epilepsy will also go on to develop Lennox-Gastaut Syndrome (LGS) with generalized tonic and atonic seizures. To complicate the neurological portion of the HH diagnosis even more, not all individuals develop seizures.

While most of us associate HH with seizures, and while probably the most common comorbidity, there is a nonepileptic seizure type that appears to be increasingly identified in the adult HH population. It is called Psychogenic nonepileptic seizures (PNES) .This diagnosis is relatively new to our community as most neurological studies have focused on the pediatric population. We will discuss this more in depth later in the blog.

For those who do experience seizures, there can be either a slow or very quick progression – from gelastic/dacrystic to absence, to complex partial, simple partial, or to any of the more severe types like tonic clonic or Grand Mal. The development of other seizure types over time suggests a process that is called secondary epileptogenesis. This process may involve the development of new seizure networks which encourage the establishment of potential seizure focal points beyond the hypothalamus.

The description of seizure types in children and adolescents with HH is well documented and you can learn more about those types here: Identify The Symptoms.

The discussion of seizure types in adults with HH has recently expanded to include a new term which can be VERY confusing. Several adults with HH have reported being diagnosed with Psychogenic nonepileptic seizures (PNES) 

The Epilepsy Foundation describes PNES as a common and complex disorder consisting of recurrent events that mimic or can be confused with epileptic seizures. Yet, while these events are sometimes discussed as seizures, they are not due to epilepsy. Their occurrence is not associated with abnormal electrical activity of the brain which is typical of epileptic seizures. In fact, the electrical activity recorded during one of these events is normal.

PNES have a sudden onset, can have a variable duration, and can present as “convulsive” and “non-convulsive” events during which the person may be responsive or unresponsive. PNES can often be misdiagnosed as intractable (difficult to control) epilepsy. In fact, 1 of every 4 people admitted for evaluation with this diagnosis do not have epilepsy and most have PNES. Often, it may take years to make the diagnosis.

PNES can have different causes. Psychiatric causes can often, but not always, be identified. Its diagnosis can be easily achieved with a video-EEG (electroencephalograph) monitoring study. Unfortunately, PNES is one of the medical disorders that often goes untreated. It is important to understand that PNES and epilepsy are treated differently and treating one with the wrong approach can mean years of unnecessary stress.

The good news is that there are treatments available for these events.  It will be important for individuals with HH to recognize that being diagnosed with psychogenic seizures doesn't necessarily mean the person has a serious psychiatric disorder. Learning what the diagnosis means and what it doesn't mean is very important. While the causes of PNES in association with HH is far from well understood by the medical community, identifying one more potential component of HH in our adult community is very important to us all.

Coming next month is our HH Comorbidity Survey – it will be a huge opportunity for all of us to have our experiences documented and presented at the 4th International HH Symposium for professionals in Washington DC. We plan to address all of the comorbidities we have been discussing in this series of blogs. We recognize that the large portion of studies up until now have focused on the younger individuals and neurological symptoms. We would like to better understand and document the adult experience. Stay tuned and perhaps start your list of concerns or issues that are having the greatest negative impact on your quality of life – for both the individual with HH and the family!

If you have been diagnosed with PNES, I would love to hear about your experiences – both good and bad. Feel free to share your story with me at lsoeby@hopeforhh.org.