Acute Altitude Sickness

I apologise for not posting in the last week, I was fortunate to go skiing in the Alps, which was great fun and we had fantastic weather! Whilst I was there a family friend experienced severe headaches, fatigue and repetitive nosebleeds and was later diagnosed with Acute Altitude sickness. I had never heard of this, and what the cause behind it is so I decided to do a post about it. 

Acute altitude sickness occurs at above 2,400m and we were staying in Tignes, which reaches a height of 3030m that makes it a clear location for it to occur. In the mountains there is reduced air pressure and reduced levels of oxygen, these are the cause for mountain sickness because there is increased pressure in the brain caused by swelling or leaking of blood vessels. The sickness is also more common if you’ve had it before or if you climb the mountain quicker or if you do vigorous exercise. It is mild and its symptoms include dizziness, fatigue, nausea, lack of appetite and headaches.

However there are two more severe forms of altitude sickness known as HAPE and HACE, they often occur together and can be very fatal. HAPE stands for high altitude pulmonary edema; the major symptom is feeling breathless when you are at rest, which shouldn’t happen even at high altitudes.  HAPE is when there excess fluid in the lungs, it prevents fresh air getting into the lungs by blocking the air spaces and because the lungs are starved of oxygen blood vessels react by constricting. The blood in these vessels is squeezed so blood pressure goes up which forces fluid of out blood and into air pockets. Other symptoms shown can be coughing up frothy spit and a high temperature.

HACE stands for high altitude cerebral edema and has symptoms very different to HAPE these are dizziness, clumsiness and stumbling, these all occur due to fluid in the brain. This fluid is due to excess blood flowing into the brain, however this can damage blood vessels, which can lead to leaking. It is also believed that chemicals are released when oxygen levels are low which can damage blood vessel membranes.

Both HACE and HAPE are life threatening and so a decent down the mountain would be essential and oxygen bags can extend life time in severe cases. 

Sources:

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001190/  

http://www.altitude.org/altitude_sickness.php

How does exercise affect the brain?

One of the most interesting things about neuroscience is that your brain isn’t restricted to a certain about of neurons. A neuron is a cell that is part of the body’s nervous system, which transmits and receives electrical and chemical signals. It has the ability to send information over a long distance due to its electrochemical aspect. It has a structure of three main parts: soma, axon and dendrites. The soma is the body of the cell, it contains the nucleus that holds the majority of RNA, also in the cell there are ribosomes and endoplasmic reticulum. The function of the axon is to transmit information to other muscles, organs and cells through electrical impulses. Some types of neuron have no Axon so they emit the signals from their dendrites. However the main role of the dendrite is to process the electrochemical signal received from other neural cells, this would explain why sensory neurons have dendrites on both end of the cell.

Our brains are made of around 100 billion neural cells, produced during pre-natal development. However our brain can create new ones during neurogenesis in the hippocampus and sub ventricular zone.  During this process neural stem cells are capable to differentiate into brain neurons via external stimulus. Once these cells have become specialised the brain is replenished with unspecialised cells, giving them the opportunity to differentiate in to new neurons providing no limit of the brain’s capacity.

Research has shown for exercise to cause neurogenesis, due to the production of BDNF (Brain-Derived-Neurotrophic Factor) proteins. When you exercise it is believed BDNF is released due to the stress factor, in order to protect current neurons as well a promote the production of new ones. The other purpose of BDNF production is to promote the ability of connection between two neurons to change in strength in response to stimuli, this is known as Synaptic plasticity. BDNF is secreted due to the influx in calcium (which is due to the rise in stress levels) because it causes transcription on nerve cells within the hippocampus and the transcription causes the secretion of BDNF. MK McGovern on his article about the effect of exercise on the brain he also describes BDNF as ‘reparative’, during exercise the axons are regenerated by injured neurons by ‘neutrophin-signalling mechanism’

The hippocampus has an important job in consolidating long and short-term memory as well as spatial navigation. It is believed that the hippocampus provides declarative memory, which is long-term memory using knowledge and facts. So therefore with an increase in neurons in the hippocampus, more electrical signals can be passed around, so you’re better at memorising things. For things to be remembered, there has to be certain strength between the neurons, if two neurons receive an electrical signal then they will communicate better in the future, this is known as long-term potentiation.  

To conclude, exercise does have an effect on the brain due to the production of new nerve cells during neurogenesis which happens in the response to stress.

References

http://www.huffingtonpost.com/dr-david-perlmutter-md/neurogenesis-what-it-mean_b_777163.html

http://serendip.brynmawr.edu/bb/neuro/neuro05/web2/mmcgovern.html

http://science.howstuffworks.com/life/inside-the-mind/human-brain/brain1.htm

http://en.wikipedia.org/wiki/Hippocampus#Role_in_memory

http://www.sciencemuseum.org.uk/WhoAmI/FindOutMore/Yourbrain/Whyisyourmemorysoimportant/Howdoesyourmemorywork/Howdoneuronscreatememories.aspx

Dementia Care Home

This morning I had my first shift at a dementia care home I worked 8am-2pm. The work is more demanding and difficult that I expected and I’ve come home very tired and worn out. It’s a very much on your feet job (as I expected) and the residents have very high needs. I began with serving breakfast, each resident has a different breakfast and you organise them on different trays with their room number, it is essential to avoid foods, which many of the residents are allergic too. These trays of food are taken to the rooms, unless there are some early risers like today, in which case they eat their meal in the dining hall. Along with the food, many have newspapers and magazine requests on certain days, weekly or daily and so you have to take the right one to them. After breakfast there is lots of clearing up, and repetitive emptying and reloading of the dishwasher. During this time, you help in dressing residents, and helping them move around their rooms or from their rooms to the lounge. The most important thing is making sure the residents get their individual medication, so there is a tick and sign sheet to check this is completed. We accommodate all of the needs of the residents until lunch time, where we set and clear the tables. Some residents cannot eat, so today i fed a lady called Minnie her lunch, which we had to purify.

There are many different extents and type of dementia among the residents.

The different types include:

Alzheimer’s disease: The cause is not easily understood, however it is believed to be related to plaques or tangles in the brain which leads to death of brain cells. It is also believed to be caused by a lack of chemicals in the brain, which are involved in transporting messages. It is a disease that progressively destroys memory, therefore they have less ability to communicate, and another main symptom is mood swings.

Vascular Dementia: The symptoms are very similar to those of Alzheimer’s disease, however they are more obvious such a problems with thinking and concentration, depression, symptoms of a stoke, seizures and periods of acute confusion. The main difference between the two is the cause; vascular dementia is caused by a lack of blood supply to the brain. Therefore high blood pressure, heart problems, high cholesterol and diabetes can increase the risk. Vascular dementia branches into stroke dementia and sub-cortical vascular dementia.

Dementia with Lewy bodies: Occurs when lewy bodies (protein deposits found in nerve cells) in the brain disrupt brain activity, by interrupting chemical messengers including acetylcholine and dopamine (the reduction in dopamine is the cause for Parkinson’s disease.) The symptoms are a mix of Alzheimer’s and Parkinson’s disease; therefore they include memory and mental activity along with slowness, muscle stiffness, trembling of limbs, a tendency to shuffle when walking and a loss of facial expression.

Fronto-temporal dementia: This is includes many illnesses such as Pick’s disease and frontal lobe degeneration. All these diseases are caused by damage to the frontal and temporal lobe areas of the brain. This causes personality and behaviour change, language difficulties and change in eating habits. 

Rarer types include:

Progressive supranuclear palsy: Is due to the damage of brain cells, there are deposits in brain tissue and a loss of tissue in brain and spinal cord. Many different parts of the brain are damaged such as the frontal- lobe, so many of the symptoms are the same as Fronto-temporal dementia. Other areas include brainstem and the areas, which controls movement.

Corticobasal degeneration: Certain parts of the brain begin to shrink due to damage over time to brain cells. The symptoms get progressively worse over time, but to begin with symptoms include difficulty in controlling limbs and ataxia (loss of balance and co-ordination.)

Sources: https://www.alzheimers.org.uk/site/scripts/documents_info.php?documentID=100

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001772/

http://www.nhs.uk/conditions/Corticobasal-degeneration/Pages/Introduction.aspx

Type 2 Diabetes

Having spoken about Type 1 Diabetes and sugar high's and low, i thought i would continue my theme. I apologise for not posting over the weekend, i was on my Duke of Edinburgh practice walk, and very achey today.

Type 2 is the most common form of diabetes; it’s similar to type 1 in the fact that it’s a chronic illness and blood sugar levels are abnormal. Type 2 is an insulin deficient disease: insulin is a hormone secreted by the pancreas and with type 2 diabetes the body does not produce enough insulin so there is too much insulin in the blood, therefore blood sugar remains high. Type 2 can also be described as an insulin resistance disease, where the body cells do not react to insulin so the body is unable to use if efficiently. Therefore this differs from Type 1 where no insulin is secreted due to the destruction of Beta cells.

The cause of Type 1 and Type two are very different, although both are affected by genetics, Type 1 is an auto immune disease and Type 2 is majorly influenced by diet and lifestyle. Genetics include age and gender however lifestyle includes diet, obesity and there appears to be a link between lack of sleep and Type 2 diabetes.

Symptoms: (These are very similar to Type 1)including increased thirst, frequent urinations, feeling tired and weight loss. It is very dangerous to leave diabetes untreated (it’s estimated that 850,000 people are left undiagnosed) because high sugar levels can damage blood vessels nerves and organs. People with diabetes are five times more chance of having heart disease; they are at a bigger risk to atherosclerosis resulting in poor blood supply as it involves narrowing of blood vessels so therefore there’s a higher risk of Angina. Nerve damage in blood vessels can cause burning pain in toes or fingers, or damage to nerves in digestive system can lead to vomiting, nausea, diarrhoea and constipation. Being diabetic can lead to blurry vision due to blood vessels in the retina of the eye being damaged, due to the vessel being blocked and therefore a reduced amount of light can pass through. If the blood vessels in the kidney become blocked then the kidneys will become less effective and in serious cases result to kidney failure. Foot ulcers can develop from damage to nerves in the foot and poor blood circulation. During pregnancy it is important for women to closely monitor blood sugar levels because in the early stages it can lead to the baby having defects or leading to miscarriage or stillbirth.

Treatment: the first step is changing lifestyle which includes losing weight, regular exercise and eating well. The disease usually gets progressively worse, so this may longer be enough, so patients would have to turn to medication which would first be in the form of tablets but may later lead to insulin injections (like type 1.)

Sources: http://www.nhs.uk/Conditions/Diabetes-type2/Pages/Introduction.aspx

http://en.wikipedia.org/wiki/Diabetes_mellitus_type_2