How Low Should It Go?

August 05, 2019

Low cholesterol is supposed to be a good thing, right?

Unless it's too low, according to a new study published July 2 in the journal Neurology.

The study, performed by researchers at Penn State University, has added more evidence to the idea of a link between low-density lipoprotein (LDL) cholesterol levels and an increased risk of intracerebral hemorrhage. Intracerebral hemorrhage, or ICH, is caused by bleeding within the brain tissue itself and can be life-threatening. During an ICH, the brain is deprived of critical oxygen and blood supply, leaving sufferers at risk of brain damage.

ICH incidents are twice as common as subarachnoid hemorrhage, in which bleeding occurs in the space between the brain and the tissue that covers the brain.

The most common causes of ICH are hypertension (high blood pressure), arteriovenous malformations (AVMs) and head injuries.

The study, conducted over nine years, showed that individuals with LDL below 70 mg/dL had a 65 percent greater chance of having an ICH.

Additional results revealed that participants with LDL below 50 mg/dL had a 169 percent higher risk of having an ICH compared to participants with LDL levels in the 70 to 99 mg/dL range.

These results follow an earlier study that reported the implications of low LDL cholesterol levels regarding ICH risk.

Individuals who suffer an ICH have a 40 percent risk of death, and if they survive, 70 percent have life-altering, long-term deficits after their ICH episode.

That's why treatment for ICH is critical. The standard protocol involves stopping the bleeding, removing the blood clot and reducing pressure on the brain.

This was the treatment a 59-year-old male faced when he was admitted to a hospital with ICH in the brain stem. The patient was experiencing symptoms including blurred vision, difficulty talking, shortness of breath and an unstable gait.

To reduce the patient's risk of death and lower the chances of brain damage, he was rushed into surgery.

In the operating room, an extra protocol was added to help reduce further damage: intraoperative neuromonitoring.

"Intraoperative neuromonitoring uses electrophysiological methods such as electroencephalography, electromyography and evoked potentials to monitor a patient's neural structures and activity during surgery," said Dr. Faisal R. Jahangiri of AXIS Neuromonitoring in Richardson, Texas.

AXIS was in the operating room that day, monitoring the patient through somatosensory evoked potentials (SSEP), motor-evoked potentials (TCeMEP), electromyography (EMG), brain stem auditory evoked potentials (BAER) and cranial nerve motor-evoked potentials (CN-MEP).

It is a good thing they were there, too. While trying to find a safe entry zone into the brain stem, the attending surgeon used motor mapping of the fourth ventricle floor to find a safe entry zone to drain the bleeding.

During the motor mapping, IONM monitoring picked up responses in the left facial muscles. This guided the surgeon to avoid these areas to sites where no responses were detected.

"Without IONM, the patient could have been left with damage to a facial nerve and other nerves in the head, resulting in facial paralysis and other consequences," Jahangiri said.


Source: Medscape. Low LDL Means Higher Hemorrhagic Stroke Risk. 8 July 2019. 

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