WE ALL HAVE UNIQUE BRAINS

ED BIOCHEMISTRY: BRAIN

ED BIOCHEMISTRY: BRAIN

What are the significant values in biochemistry? 

As I mentioned back in Emergency Biochemistry in the Starting Material section, the significant values in biochemistry are all measured in millimoles per litre or mmolL-1, and they are listed in the table below. The reference range refers to values seen in about 95% of the population, and the critical low and critical high entails the extremes at which the body can tolerate before it shuts down.

Table: Original
Table: Original

What are the medical conditions that can result from extremely low or high analyte values? 

Pic: http://www.rcinet.ca/english/illustration/chronicle/8yoGJH_iStock_000001058404XSmall.jpg

Often, extreme lows or highs in the analyte values can land someone in the Emergency Department of a hospital. Almost all of the analytes that I mentioned above have a consequence which relates to injury of the brain as well as problems within the body. I’ll discuss each of the analytes separately and be discussing the consequences associated with critical high and low values.

 

 

 

 

Sodium (Na+) RR: 37-145mmolL-1 

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Sodium level extremes tend to almost exclusively affect the brain due to the process of osmosis, which forces water either in or out of cells along with the charged Na+ ions.

High Na+ 

  • Cerebral dehydration due to water being forced out of the brain
  • Intracerebral haemorrhage (bleeding of the brain)

Low Na+ 

  • Cerebral oedema (swelling) due to water being forced into the brain cells from the outside.

 

 

Potassium (K+) RR: 3.1-4.2mmolL-1 (heparin), 3.8-4.8mmolL-1 (clotting) 

Pic: http://thumbs.dreamstime.com/z/potassium-form-periodic-table-elements-6814688.jpg

The problems tend to be centred around the heart, the gut and the kidneys: the heart and gut troubles can be linked to the brain, however, due to their innervation by the vagus nerve (cranial nerve X). Low potassium levels in the blood tend to be purely clinical in nature, however high potassium levels are often artefactual, so they need to be cross-checked first. More information about clinical vs. artefactual results can be found in Emergency Biochemistry.

High K+ 

  • Cardiac (heart) arrhythmia, the heart beats but it does not maintain its normal lub-dub rhythm correctly.
  • Cardiac arrest (ventricular fibrillation): the heart stops completely
  • Kidney problems

Low K+ 

  • Metabolic alkalosis (high pH in the blood)
  • Cardiac problems
  • Gut paralysis

Bicarbonate (HCO3-) RR: 22-32mmolL-1 

Pic: http://www.derangedphysiology.com/php/Physiology-of-fluids-and-electrolytes/images/molecule%20of%20bicarbonate.JPG

Bicarbonate tends to affect both the body and the brain, however low levels of bicarbonate tend to affect the brain more noticeably.

High HCO3-

  • Severe pulmonary (lung) disease

Low HCO3- 

  • Severe metabolic acidosis (low levels of pH in the blood)
  • Impairment of nervous function
  • Coma
  • Death

 

 

Glucose (C6H12O6) RR: 3.8-5.5mmolL-1 (fasting) 

Pic: http://www.korseby.net/computer/templates/chem_glucose_f.png

The variations in glucose levels, unlike the other analytes, has a specific name attached to the disease. The condition of uncontrolled glucose levels is known as diabetes mellitus, and it has two types: type 1, which is an autoimmune disease that rids the body of insulin-producing cells in the pancreas, and type 2, which is due to resistance of insulin. The lack of glucose of blood is detrimental to the brain because of the brain’s dependence on glucose for energy.

High C6H12O6 

  • Severe hyperglyercaemia (high levels of glucose in the blood)
  • Diabetic ketoacidosis (release of ketones into the blood, which can be detected by a urine dip test)

Low C6H12O6 

  • Severe hypoglycaemia (low levels of glucose in the blood)
  • Cerebral starvation
  • Coma
  • Death

Calcium (Ca2+) RR: 2.10-2.55mmolL-1 

Pic: http://gregparham.files.wordpress.com/2010/01/calcium-form-periodic-table-of-elements-thumb6814686.jpg

Calcium has a very narrow reference range: if the results end up outside of that range, it is immediately classified as an emergency. The excess or lack of calcium affects many different organs in the body.

High Ca2+ 

  • Vomiting
  • Dehydration
  • Cardiac arrhythmia
  • Confusion due to lack of flowing blood in the brain
  • Cardiac arrest due to paralysis in the vagus nerve (cranial nerve X)

Low Ca2+ 

  • Tetanus due to nerve hyperexcitability
  • Renal (kidney) failure
  • Hypo-parathyroidism
  • Parathyroid adenoma post-surgery

Magnesium (Mg2+) RR: 0.7-0.9mmolL-1 

Pic: http://www.sophisticatededge.com/assets/images/Health/Vitamins%20and%20Minerals/What-family-does-magnesium-belong-to.jpg

Differences in magnesium levels are often associated with cytotoxic drugs: in other words, drugs that affect the cells of the body, causing them to release electrolytes. High levels of magnesium are rare but low magnesium is relatively common.

High Mg2+ 

  • Renal failure
  • Eclampsia
  • Tetanus

Low Mg2+ 

  • Infusion of cisplatin leading to renal (kidney) tubules leaking magnesium.