What should we really know about cerebral aneurysms?

Cerebral aneurysms are scary things. It is alarming enough that they exist, but it is more spine-chilling that they enlarge with time. The most infamous aneurysm arises from the posterior communicating artery, the so-called PCOM aneurysm. And it signifies its sinister intent when it gradually enlarges and compresses its vascular neighbour, the third cranial nerve, otherwise known as the oculomotor nerve. A dysfunctional third nerve manifests with a droopy eyelid (ptosis) and double vision (diplopia). The reason for the double vision becomes obvious when the neurologist examines the eyes; one eyeball is out of kilter and is deviated downwards and outwards; it is indeed down and out! The pupil is also very widely dilated (mydriasis). These are among the most worrying red flags in medicine, and a very loud call to arms. Cerebral aneurysms however often wave no flags, red or otherwise. Indeed the most malevolent of them will expand quietly until they reach horrendous proportions, and then, without much ado, just rupture. They are therefore veritable time bombs…just waiting to go off.

By Tiago Etiene Queiroz – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=24418848

Cerebral aneurysm however do not need to reach large proportions to rupture; some just rupture when they feel like. Aneurysms under 7mm in diameter however are less prone to rupture. A rupturing aneurysm presents with very startling symptoms. The most ominous is a sudden onset thunderclap headache (TCH), subjects reporting feeling as if they have been hit on the back of the head with a baseball or cricket bat. It is not quite known what non-sporting patients experience-for some reason they never get aneurysms in neurology textbooks! More universally appropriate, a ruptured aneurysm may manifest as sudden loss of consciousness. Both symptoms result from leakage of blood into the cerebrospinal fluid (CSF) space, a condition known as a subarachnoid haemorrhage (SAH).

By Lipothymia – Anonymised CT scan from my own practice, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=787177

You may breath a small sigh of relief here because the vast majority of people with thunderclap headaches do not have subarachnoid haemorrhage. Unfortunately, every person who presents with a thunderclap headache must be investigated- to exclude (hopefully), or confirm (ruefully), this catastrophic emergency. The first test is a CT head scan which identifies most head bleeds. The relief of a normal scan is however short-lived because some bleeds do not show on the CT. The definitive test to prove the presence or absence of a bleed is less high tech, but more invasive: the humble spinal tap or lumbar puncture (LP). This must however wait for least 12 hours after the onset of headache or blackout. This is the time it takes for the haemoglobin released by the red blood cells to be broken down into bilirubin and oxyhaemoglobin. These breakdown products are readily identified in the biochemistry lab, and they also impart on the spinal fluid a yellow tinge called xanthochromia. The test may be positive up to 2 weeks after the bleed, but the sensitivity declines after this time. A positive xanthochromia test is startling and sets off an aggressive manhunt for an aneurysm-the culprit in most cases. 

By Ben Mills – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=13051957

Many people with cerebral aneurysms have a family history of these, or of subarachnoid haemorrhage. Some others may have connective tissue diseases such as Ehler’s Danlos syndrome (EDS), adult polycystic kidney disease (APCKD), or the rare Loeys-Dietz syndrome. This family history is a window of opportunity to screen family members for aneurysms. The screening is usually carried out with a CT angiogram (CTA) or MR angiogram (MRA). People are often not born with aneurysms, but tend to develop them after the age of 20 years. Aneurysm surveillance therefore starts shortly after this age, and many experts advocate repeating the screening test every 5-7 years until the age of 70-80 years.

By Nicholas Zaorsky, M.D. – Nicholas Zaorsky, M.D., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15533196

How are aneurysms treated? This will be the subject of a future blog post so watch this space!


Revealing the invisible rhinoceros: paying attention to adult ADHD

Adult attention deficit hyperactivity disorder (ADHD) is a key psychiatric disorder. It is characterised by some core clinical features which are hyperactivity, inattention, impulsivity, disorganisation, and low stress tolerance. People with ADHD have several life impediments that characterise their day-to-day lives; these include difficulty starting tasks, struggling to prioritise, and failing to pay attention to details. Enduring chaotic lifestyles, they struggle to keep up with their academic, employment, and relationship commitments.

ADHD. Practical Cures on Flickr. https://www.flickr.com/photos/practicalcures/23280349432

For the public and for most physicians, ADHD is recognised only as a childhood disorder. But 10-60% of childhood onset ADHD persist into adulthood. Furthermore, about 4.5% of adults have ADHD. The failure to recognise ADHD as an adult problem therefore means it is easily missed in adult psychiatry and neurology clinics. Referring to this in a review published in the journal Psychiatry (Edgmont), David Feifel labelled adult ADHD as the invisible rhinoceros (you must read the article to understand why it is not the elephant in the room). Concerned that many adults with ADHD are misdiagnosed as suffering with anxiety or depression, he urged psychiatrists to routinely screen for adult ADHD in every adult presenting with these disorders.

Southern White Rhino. William Murphy on flickr. https://www.flickr.com/photos/infomatique/34467891470

The scale of the failure to diagnose adult ADHD was emphasised by Laurence Jerome in a letter to the Canadian Journal of Psychiatry. Titled Adult attention-deficit hyperactivity disorder is hard to diagnose and is undertreated, his letter highlighted the finding of the US ADHD National Comorbidity Survey which concluded that most adults with ADHD have ‘never been assessed or treated’. He argued that this oversight places heavy lifetime burdens on adults with ADHD such as impaired activities of daily living, academic underachievement, poor work record, marital breakdown, and dysfunctional parenting. A great burden indeed, but a preventable and treatable one!

ADHD. Bob on Flickr. https://www.flickr.com/photos/contortyourself/5016270276

How is all this psychiatry relevant to the general neurologist? Well, many manifestations of ADHD are the stuff of the neurology clinic. Cognitive dysfunction for example is prevalent in adult ADHD, and it may present to the neurologist as impaired short term memory, executive dysfunction, impaired verbal learning, and, of course, impaired attention. Sleep related disorders are also frequent in adult ADHD, and these include excessive daytime sleepiness (EDS), restless legs syndrome (RLS), periodic leg movements of sleep (PLMS), and cataplexy. There are also several other neurological co-morbidities of adult ADHD such as epilepsy and learning disability.

ADHD. Jesper Sehested on Flickr. https://www.flickr.com/photos/153278281@N07/38447999522


It is therefore high time for neurologists and psychiatrists to reveal the invisible rhinoceros!