August 12, 2008
Hey everyone. My blog will be on temporary hiatus as I focus on more pressing issues. I.e. getting my UCAS form in order, UKCAT and BMAT. Once that is all over, my articles will return. Thanks for reading!
Filed under: Personal | Comments (0)
August 9, 2008
Creutzfeldt-Jakobs Disese and Variant Creutzfeldt-Jakobs Disease may have similar names. But they differ greatly. People who suffer from CJD and vCJD have similar symptoms (as they progress):
However, there are many differences between CJD and vCJD. CJD takes a short while (from onset of symptoms) to progress to death (~5 months), where as vCJD takes 13-14 months. vCJD sufferers also experience differing symptoms such as dysestheria (where un-real sensations are felt, such as burning or pins and needles). The most striking difference between Classical CJD and variant CJD is the age of onset. Classic CJD occurs in older patients around 70 years old (which is why symptoms are usually mistaken for Alzheimer’s Disease). Variant CJD effects younger people, with an average age of onset being 20-30, with the youngest sufferers being 14! This suggests a fundamental difference between the two infectious prion agents.
BSE or Bovine Spongiform Encephalopathy is a prion disease similar to the human-form: CJD. It affects cows and peaked in the UK in 1993 with 1000 new cases per week! It was spread by using contaminated cattle-feed that contained infected neural tissue. Before 1989, Cattle where fed MBM (Meat and Bone Meal) which contains offal (unedible parts of cattle: i.e. brain, where prion proteins were concentrated). Therefore the use of MBM facilitated the spread of BSE, and as more cows became infected and died, more infected MBM was created. It is thought that BSE originated from one cow who spontaneously contracted the disease (just like sporadic creutzfeldt-jakobs disease). There is an almost indisputable link between the BSE prion and the vCJD prion.
If mice are infected with the BSE prion, there is an incubation period of roughly 250 days, after which classic symptoms occur. If mice are now infected with the brain tissue of the first infected mice, they too become infected after 250 days. The Astounding piece of evidence, is if mice are infected with vCJD brain tissue…The incubation period is the same 250 days! This showed that there was no significant species barrier that prevented transmission (although as you see later, one does exist), and the vCJD and BSE prions were indistinguishable as they both had identical incubation times.
So far, around 160 people have died of variant CJD. The problem is, they were all of a certain genetic make-up. The gene that codes for the normal PrP protein has two alleles: M and V, which use a different amino acid in the primary sequence of the PrP protein. Everyone who has died of vCJD (bar one) has had the MM genotype. The one non MM person who died, was an MV genotype, and died due to an infected blood transfusion. It has been hypothesised that the previous assumption that: “only the 40% of the population (MM) can get vCJD from infected beef” is wrong, and that other genotypes don’t prevent you from getting the disease, but only delay the age of onset. Mice with the MM, MV and VV genotypes were infected with BSE. MM genotypes developed clinical signs of prion disease, where as the MV and VV genotypes did infact have the disease, but expressed no clinical symptoms. This suggests that people with the VV and MV genotypes simply have a long incubation period before clinical symptoms. This is further backed up by the incidences of kuru in Papa New Guinea whereby the incubation period was about 40 years! Hence, we could be seeing a huge CJD epidemic where up to hundreds of thousands of people are infected and exhibit clinical symptoms in the future.
It has been estimated that most people have been exposed around 80 times to the BSE-infected meat. This certainly doesn’t puport that everyone is infected, as many MM genotypes were obviously not affected. It has been estimated that one infected cattle that is allowed into the food-chain has the potential to infect only 1 and 2 people due to a substantial species barrier and the fact that eating meat is a poor method of transmission as opposed to blood transfusions or corneal implants.
Filed under: Medical Article, Uncategorized | Comments (1)
August 7, 2008
In this blog post I wish to talk about the puported mechanism by which alzheimer’s disease causes neurone death and ultimate atrophy of the brain. The areas in which Alzheimer’s affects are the temporal lobe, the parietal lobe, the frontal lobe and more.
Alzheimer’s is currently an incurable degenerative brain condition. Death usually occurs within 8 years of being diagnosed, but not due to the alzheimer’s, instead patients die due to complications such as bed sores, pneumonia etc. Alzheimer’s disease progresses from mild cognitive impairment (I.e. difficulty learning new facts, skills and reduced vocabulary) to moderate and then advanced dementia where patients become more and more incapable of remembering information, can develop urinary incontinence, have unpremeditated aggressive outbursts, become incapable of performing the most simple of motor tasks and eventually becomes bed-ridden and in need of feeding. Familial Alzheimer’s occurs within a family and is ‘early onset’, whereas the other, more common ‘Sporadic Alzheimer’s’ occurs at around 65 years of age and older.
The cause of this horrible disease on a molecular level is not 100% decided, but a popular hypothesis
is that protein plaques that build up in the brain cause neurone death. The image on the right is a representation of the interactions with the APP protein (Amyloid Precursor Protein). These proteins are cleaved by the enzymes called secretases. There is alpha-secretase, beta secretase and gamma secretase, and they all cleave at different points along the APP protein. If Alpha-secretase cleaves the APP first, followed by gamma secretase, there is no amyloid build up. However, if beta-secretase cleaves APP first, followed by gamma-secretase, Amyloid-Beta-42 can be created, or Amyloid-Beta-40. if Amyloid-Beta-42, or AB42 is created (which is more hydrophobic and hence can aggregate easily) extracellular plaques will build up around the neurones. It has been shown that this alone is insufficient to kill neurones. It is thought that AB42 plaques on the surface of cells open ‘pores’ or calcium channels in the cell. This allows the influx of Ca2+ ions into the cell, which activate kinases (which will be explained later).
Some Neurones are very long, and therefore to transport nutrients throughout the neurone, microtubules are used which span about the cell. Special tau proteins bind to the microtubules to maintain and regulate them. However active kinases (enzymes which deposit phosphate groups) hyperphosphorylate the tau proteins, causing them to stick to themselves, as opposed to the microtubules. This creates NeuroFibrillaryTangles (NFTs) which aid in neurone cell death as the microtubules begin to fall apart. In addition to this, the amyloid plaques lead to an inflammatory/immune response using ‘astrocytes’ and microglial cells which when activated produce harmful free-radicals leading to neurone death.
In Familial Alzheimer’s genes on chromosomes 14, 1 and 21 are responsible. These genes don’t have anything to do with tau proteins which suggests that tau proteins do not initiate Alzheimer’s (at least Familial). The gene on chromosomes 14 and 1 are Presenilin-1 and Presenilin-2 respectively and abnormal alleles cause APP to more likely create AB42 instead of AB40 when cleaved by gamma-secretase The gene on chromosome 21 codes for APP itself! If there is a mutation, it is more preferentially cleaved by beta-secretase then alpha-secretase. People who have Down’s Syndrome have 3 lots of chromosome 21 and frequently develop alzheimer’s disease by the age of 40. Another gene on chromosome 19 called the Apolipoprotein e is considered a high risk factor of Spontaneous Alzheimer’s rather than a cause of familial alzheimer’s as it is associated with a much higher risk of AB42 build up in the brain.
Filed under: Medical Article | Comments (0)
August 6, 2008
Today I wish to talk indepth about the process of HIV replication, which is a multi-stage and complex process. 
Each stage of the replication process gives potential for drugs to fight HIV infections by disrupting said specific stage and preventing the HIV life cycle from completing. Before we start, here is a diagram I whipped up on MS paint (yes I am an MS-Paint god) labelling all important parts of the HIV virus and a T-helper lymphocyte.
Step 1: Attachement and Fusion
Before an HIV virus can replicate, it needs to find a host. To bind with a host it needs to bind with specific receptors found on the membrane of certain cells (T-Helper lymphochytes). These receptors are called CD4 receptors examples of which include CXCR4 and CCR5. As well as these receptors, there are co-receptors, which encourage further binding between the HIV virus and the lymphocyte. The binding occurs between glycoprotein 120 (gp120, which is extracellular) and a CD4 receptor. This binding action changes the shape of gp120 causing the trans-membrane gp40 to fold into the plasma membrane of the lymphocyte. gp40 then folds in on itself drawing the virus towards its target causing a fusion of the viral envelope and plasma membrane. The capsid core contained within the virus is released into the cytoplasm of the lymphocyte where the core proteins surrounding it break down. This releases the main agents used in replication: Viral RNA and 3 enzymes: Integrase, Reverse Transcriptase and Protease.
Step 2: Enter Reverse Transcriptase
This step involves the use of the reverse transcriptase enzyme. Which is found in retroviruses and have been used to create recombinant DNA for genetic engineering (i.e. it was used to insert insulin creating gene into bacteria). It does the reverse of DNA transcription which involves converting DNA into mRNA. Therefore Reverse Transcriptase converts RNA into DNA, which has two important active sites: the ribonuclease H active site and the polymerase active site. The polymerase active site attaches to the viral RNA in the cytoplasm and as the RNA moves through the active site, an RNA/DNA double helix is created. This RNA/DNA strand attaches to the ribonuclease H active site causing the RNA single strand to be broken down to leave a single DNA strand, which in turn attaches again to the polymerase active site creating double stranded DNA which contains the instructions to make more HIV.
Step 3: Enter Integrase
This step involves the enzyme integrase, which cleaves 2 nucleotides from opposite ends of the DNA double helix (2 nucleotides per strand) resulting in parallelogram shape if the strand is straightened out. This results in the DNA getting ’sticky ends’ allowing it to be inserted into the target cell’s genome. The integrase enzyme carries the sticky DNA into the nucleus where it assists its integration into the cell’s genome.
Step 4: Enter Protease
The Target cell has now effectively become a ‘virus factory’ and will start creating the materials required for viral replication. mRNA from the transcription of the viral DNA is then translated by tRNA to make ‘building-block’ proteins, some of which are too long to be used. Viral RNA is also replicated and when all necessary components of HIV have been created (e.g. the gp120 and the gp40 proteins) with the proteins being correctly spliced by the protease enzyme, the budding process occurs by which an immature virion buds from the plasma membrane of the host cell. Maturation occurs either during or after budding when protease cleaves the many polyproteins into functional proteins such as structural caspid core proteins or enzymes. The virus is now mature and ready to infect another cell
Each infected host cell can make huge numbers of virions before dying allowing HIV to make billions of copies daily. As the disease progresses, an HIV sufferer’s immune system becomes more and more compromised.
Anti Retro Virals:
Because HIV is multi-stage process, there are many ways in which replication can be halted.
We have:
Even though these drugs are effective, due to the extremely error prone Reverse Transcriptase stage many mutations occur! This leads of a high frequency of drug resistance which I was told by doctors (in the virology lab during work experience) could develop in weeks with non-adherent patients. It is therefore suggested a combination of 3 drugs are taken to further reduce the chance of a drug resistant strain occuring. However, thanks to many medical advances in the treatment of HIV, the disease has gone from a death sentance, to a chronic disease. Such as Hepatitis C, Diabetes, Cancer, COPD etc.
Filed under: Medical Article | Comments (0)
August 4, 2008
Day 4 - The 4th day of my second week was spent on the wards with 2 junior doctors. Due to lack of activity about the wards, and the unavaliability of the registrars and consultants the day ended early at lunch time. However, even though my time in the hospital was short, I witnessed a very interesting and saddening case. I began the day with ward rounds following the junior doctors, I saw one patient who was very weak. She had metastatic cancer which had spread to her liver, brain and various other places. She was terminal and I was told that everything that could go wrong, did go wrong for her. Originally she was highly allergic to the initial chemotherapy given and was switched to Heperin, however this caused her heart to fail, leaving the doctors with very few options and I was told that she now only had mere weeks to live. When I saw her I observed her physical state:
The doctors were trying to decide whether to give her radiotherapy to the brain in an attempt to extend her life but were worried the cancer in her liver would kill her before the brain tumour would anyway. They decided to give her a blood test to check liver enzyme levels (if they were abnormal, it would suggest her liver was failing). However, she was so swollen that her veins were near impossible to get to, with the junior doctor trying for 5 minutes to find a suitable vein whilst the patient whimpered in agony. In the end, a tiny amount of blood was drawn with the doctor realising it was insufficient for a blood test. Eventually they decided they would give her radiotherapy as she didn’t appear jaundiced which was a possible sign that her liver was not going to fail in the near future.
Another saddening fact about this case was that the patient was a mother with her kids (who were visiting that day) unaware that their mother was terminal and close to death. Originally the patient was reluctant to tell her family, but after bringing in some registrars and a social workers, they managed to get her consent to explain to the children, their mother’s condition.
I next saw a blind cancer patient and despite the fact that he was quite likely terminal, he was still in good spirits, playing with the doctor when he asked him to stretch out his arms and legs, while laughing.
Finally, before I went home, I saw one last patient. He was an elderly man who had suddenly become confused and aggressive after radiotherapy. When we entered his room, he refused to open his eyes for the junior doctor and started demanding that we left. It was rather depressing to see this old man so frightened and confused but suprisingly the junior doctors dealt with it extremely well and continued to be bright and cheery.
Day 5 - My final day of work experience entailed me visiting a pathology lab at another hospital, meaning I was only able to observe oncology related medicine until lunch. In the morning I sat in during a clinic with a senior consultant radiotherapist. His first patient was an extremely cheery man who had an extremely swollen face which looked almost twice its normal size due to large amounts of steroids he took to treat the symptoms of his glyoma. I was surprised to learn that he only had less than 1 year left to live due to his positive and joking attitude but it was clear he was enjoying the remainder of his life to the full!
The next patient that was seen was a lady in her 50s. She had beaten cancer before once and was a long time friend of the oncologist. She recently had a CT scan to check for any relapse of cancer. Unfortunately, while she went to the bathroom, we observed the CT scans and saw many small tumours in her liver. When she returned, the doctor gave her the grim news and said it was most probably terminal. Unfortunately she mistook this for meaning “there was a good chance that it wasn’t terminal”. Sadly the doctor had to correct her and say that it was almost certainly terminal, and that she was looking at around 6 months left to live. This came as a massive shock to her and after a few minutes of silence and a few tears, she regained her composure and said “Thank you for treating me. Because of you I saw my grandchild. Thank you” The doctor then said “Listen, I was wrong about your prognosis once before, I’ll be wrong again I’m sure” while she was escorted from the office by her sister who actually appeared sadder then her. I was very struck by her stoic nature and fierce determination to never give up fighting and I wish her the best of luck.
The next patient I saw was a middle-aged indian woman who was battling metastasized thyroid cancer. Luckily for her, tbhe condition wasn’t terminal as thyroid cancer and resultant secondary tumours are easy to treat with the radioactive isotope of iodine which the tumour cells absorb several orders quicker than normal cells. I then saw a lady with a brain tumour pressing against her cerebellum, which controls coordination and balance. She was showing many symptoms. For example, the doctor asked the patient to touch his pen. She reached out for the pen normally, however as her fingers closed in on the target, her whole hand shook profusely due to her inability to precisely place her fingers. She also was unable to speak properly, with words missing in sentances and severe slurring of the words that were spoken.
After this patient, it was nearing lunchtime, so I thanked the consultant and the two registrars for all the time they had given me throughout the week and set off to another nearby london hospital to visit the pathology lab! As I entered the pathology lab I was greeted by a length of large intestine on a nearby table which I was told belonged to a 70 year old man who was still alive! It had been taken out due to fluid in the abdominal cavity which is usually caused by perforations in the gut. Surprisingly no perforations were found throughout the gut but large quantities of pus coated the outside of the intestine. After seeing the intestine, I was introduced to an eye that was heavily afflicted with cancer and had grown to the size of a tennis ball followed by a slice of a tumour about the size of a dinner plate. My initial shock grew as I was told that tumours they receieve sometimes are as wide as two arm lengths! Finally I was greated by a placenta which had attached to it an umbilical cord which was extremely knotted and irregular (which was normal apparantley). I was told that if twins are present, two umbilical cords hang from the placenta and sometimes they can tangle and intertwine, resulting in a C-section birth. All the body parts were treated in formalin to prevent rot and the subsequent smell.
After viewing all the preserved body parts they had on offer, we got taken to the microscope room where we viewed slides of different cancer patients. We observed a slide from a lymphoma sufferer which showed cancerous lymphocytes upto 20 times bigger than normal!As the day was coming to a close We lastly saw slides of cervical and gallbladder cancer where the nuclei of the tissue were irregular and orientated differently and I was told that this was a tell-tale sign of cancer. As we moved about the slide, we saw cancer cells breaking off from the primary tumour. This occurs commonly with metastasis happening only if certain rare requirements are all met: the tumour must first invade the a blood sell (intravasation), the tumour cells must then be able to survive in blood circulation, the tumour cell must then be able to enter an organ or tissue (extravasation) and finally, it must be able to grow and perform angiogenesis (the formation of blood vessels to supply nutrients to the tumour). If all these rare requirements are met, the tumour will metastasize, however the slide just showed tumour cells breaking off into the blood stream with none of the other requirements being necessarily met. After the exciting afternoon in pathology had ended, I thanked the consultant pathologist and left. As I was leaving I was saddened by the fact that my work experience was over, but I had learnt huge amounts of info about the life of doctors, patient care and medical facts! In one of my next blog posts I will blog specifically about what I learnt during my work experience. I hope you enjoy!
Filed under: Personal, Work Experience | Comments (0)
August 4, 2008
Day 2 -
The day started with an extremely long meeting about patient treatment in an extremely small, hot room followed by following the junior doctors around for rounds where I learnt a few interesting facts: junior doctors never follow the guideline for work hours, and always end up having to do unpaid extra, central lines are used if people’s veins are to damaged/collapsed although this increases the risk of infection (MRSA for example, can enter via a central line wound), bone biopsies are done with a very painful screw and finally I learnt that it was a necessity to ensure elderly patients had care waiting for them when they discharged. After the ward rounds, we had lunch, and I spent the rest of the day with a consultant in radiotherapy planning in which custom masks were fitted to keep patient’s still and preliminary CT scans were performed (in conjunction with more advanced ones later) to allow the physics department to decide on the correct treatment dosage and the movement path the radiotherapy machine makes.
I also learnt interesting facts about CT scanning: lymphatics never show up on CT scans therefore doctors look inbetween the veins and arteries in CT scans for lymphomas (as lymphatics are present in between veins and arteries), I also learnt that a full-body CT scans takes ~5 minutes however when CT scans were first invented, the whole procedure took hours per individual CT slice! Finally, I was told by a nurse that there had been a huge increase in younger people (30s) coming in with aggressive lung cancers, she told me that they all smoked cannibis.
Day 3 -
We started day 1 with a meeting similar to the one described in my previous blog post, where patient treatment was discussed. For the most part, the meeting involved locating tumours on CT scan images, with doctors proposing a method of treatment, and the rest of the room agreeing. After the meeting, I stayed with the consultant radiotherapist for his clinic session.
The first patient I saw was someone suffering form glyoma, which is the most common brain tumour in adults. Due to the fact that this aggressive cancer was located deep within his brain, surgery was not an option. Instead, steroids were perscribed to help aleviate the fluid buildup in the brain. To my astonishment, after the patient had left, I was told that glyoma sufferers usually only lived for <2 years maximum after diagnosis. The next patient I saw was a woman with thyroid cancer, a symptom of which is bulging eyes (of which the woman had, causing double vision). Fortunately for her, thyroid cancers are very treatable. The reason for this is as follows:
After the clinic session in the morning, I was sent on ward rounds with the junior doctors. I observed a 3rd year doctor undergo some sort of assesement test. It was very bureacratic and seemed very unimportant and obsolete (much to the agreement of all the doctors present). I was allowed to listen to a patient’s heartbeat on a stethoscope which was very interesting and novel and sounded like an extremely dull, faint thud. The assesement test involved a 1st year registrar observing the 3rd year doctor perform a standard check up. She first looked at the patient to check for obvious physical maladies (i.e. a small case of vitiligo that went unnoticed), she then placed two fingers on the patient and smacked them with the knuckles of her two fingers from her other hand. The purpose of this was to check for fluid in the lungs (as a ‘hollow’ and healthy lung would make a loud, sharper thud, where a ’solid’ and fluid filled lung would make a muddier and deeper thud). Finally, the doctor checked the heartbeat of the patient using a stethoscope to check for heart conditions such as tachycardia.
Following the ward round I followed the 1st year registrar to a room where he was to brief a 30 year old breast cancer sufferer on her treatment (radiotherapy and chemotherapy) and the subsequent side-effects which were:
I finally finished the day in the medical physics department where I observed them devising a radiation treatment sequence for a cancer sufferer. They used ‘boluses’ which were shapeable blocks of skin-like substance used to control and alter the dosage for certain areas of the body. If a cancer was very close to the skin, they would place a bolus ontop of it as the radiation dosage is low on the surface of the skin, and subsequently rapidly increases. Therefore a strategically placed bolus would amplify the dosage of radiation so by the time it reached the cancerous tumour, it would be sufficiently powerful to kill the tumour. As I was leaving I started to have a conversation with the consultant who had arranged the work experience for me in which he explained the basis of radiotherapy to me. Originally I knew that radiotherapy ‘killed cancer cells’, but that was the extent of my knowledge. During the discussion I was told that the radiation from the radiotherapy kills indiscriminantly (tumour and healthy cells alike). However, the fact that they provide many small doses of radiation allows an accumulative effect to occur. The healthy tissue that is irradiated can heal inbetween the doses of radiation, however the cancerous tissue is unable to heal and hence the damage done by the radiotherapy build up to an extent where the cells are either sterilised or killed. The fact that cells are sometimes sterilised instead of killed leads to the common misconception that radiotherapy ‘keeps working after treatment’, when infact it just takes time after the cancer cells are sterilised to be killed or to die.
Filed under: Personal, Work Experience | Comments (0)
August 1, 2008
Today is the first time I will be talking about a non-infectous disease! The disease I wish to talk about is Amyotrophic Lateral Sclerosis, or ALS. It is a progressive disease of the upper and lower motor neurones in the body in which they slowly degenerate. This slowly paralyses the whole body of the patient except for the eyes (which in some cases can also become paralysed). The brain however, remains unaffected (aside from occasional and slight dementia). This ailment effects the famous astrophysicist: Steven Hawking and is usually fatal 10-20 years after symptoms occur.
Mechanism: the mechanism by which ALS works is not known, but well-founded theories exist. People with ALS have a mutation in their DNA (in familal ALS) that causes the transcription and subsequent translation for a protein that is used to create the enzyme: SOD1. SOD1 is a powerful antioxidant which removes superoxide free-radicals. It was once thought that accumulation of superoxide free-radicals in motor neurones lead to degradation of said neurones. However, mice with the gene that codes for SOD1 removes entirely did not suffer from ALS. But instead suffered a shortened lifespan and other ailments such as muscle atrophy, cataracts and carcinoma. This suggests that ALS is not caused by the loss of function of SOD1, but instead a gain of function! It is thought that misfolded mutant SOD1 enzymes form unwanted masses of proteins called ‘aggregates’. These build up in the cell and disrupt cellular activity such as mitichondria. This suggests that aggregates are the cause of SOD1 enzyme toxicity. However, familial cases only make up a 5-10% of the sufferers with 90-95% of cases occuring due to sporadic ALS.
Another theory is that the neurones degenerate due to higher than normal levels of glutamate in spinal fluid and in blood plasma. It has been shown that neurones surrounded by high levels of glutamate will slowly die off. This has led to the creation of the first FDA approved treatment for ALS: Riluzole, which lowers glutamate levels and increases life-span by a few months by slowing the progression of the disease.
Symptoms and Progression: symptoms to begin with are extremely subtle, and are often ignored. ALS begins with muscle weakness, twitching (due to loss of nerves), cramping and stiffness of an affected muscle. This is sometimes accompanied with slurred speech. Most patients experience the first ALS symptoms on a limb muscle: such as a leg or arm. However, 25% of cases are ‘bulbar onset’. These patients in particular, first notice problems speaking, with speech becoming garbled and incomprehensible in conjunction with difficulty swallowing. Eventually, speech is impossible and the airway is not closed during swallowing. as ALS progresses, all patients have trouble swallowing, speaking and muscle weakness spreads to other body parts with hyperreflexia (over-active reflexes) occuring. Some patients experience the pseudobulbar effect whereby patients are overcome with uncontrollable bouts of laughter, crying and smiling. This is due to the degeneration of neurones associated with displaying facial emotion. Patients will notice difficulty performing tasks: walking, running, inserting a key into a lock or any other tasks that requirew dexterity of the hands.
Eventually, sufferers will be unable to get out of bed, walk around or move their arms and will be confined to their bed. Sufferers will not experience any significant cognitive changes apart from a few who experience dementia. Many patients who are aware of their condition become depressed and anxious. Other slight cognitive changes are observed i.e. difficulty in making decisions. (This could be due to the disease, or due to difficulty breathing while sleeping: hypoventilation). Eventually the diaphragm and intercostal muscles weaken meaning it is more and more difficult for patients to breathe. Eventually they have to make a choice between longterm machine-aided respiration, or palliative care in a hospice. Many choose the latter. The senses, along with eye movement are preserved, however patients living along time with ALS (20+ years) tend to lose eye function too. Most patients die of respitory collapse as their weakened muscles and degenerating neurones are unable to breathe at a sufficient rate and force.
Transmission: 5%-10% of patients with familial ALS receive the faulty gene from their parents. The allele that causes ALS is dominant, meaning there are no carriers and you have a 50% chance of inherting it if one of your parents suffers from ALS (75% if both of your parents suffer from ALS). The rest of ALS cases occur sporadically and are therefore caused by a spontaneous mutation.
Prognosis and Treatment: The prognosis for ALS sufferers is not good: with people dying of respitory collapse 3-5 years after the onset of symptoms. 10% of sufferers can live for more than 10 years however. In addition it should be known that some sufferers of ALS have an arrested course. Where no more progression occurs.
Treatment, aside from Riluzole is purely palliative and to alleviate the symptoms of sufferers. Medicine can be perscribed to reduce muscle cramps, pains and stiffness. Drugs are also perscribed to reduce phlegm and saliva production and to prevent constipation. Light aerobic excercise is also given to increase cardiovascular health and improve the mental-state of the patient (i.e. alleviate depression). When speech becomes incomprehensible, alternative-communication devices may be used such as amplifiers. Feeding tubes are used as they reduce risk of pneumonia (via liquid being inhaled into the lung) and choking. Calorie Restriction is also avoided as it is thought that patients on a restricted calorie diet suffer from more rapdily progressing ALS. Finally, if the patient wishes, a mechanical respirator will be inserted to aid breathing, however, the patients must be informed and understand that they will live without any movement.
Filed under: Medical Article, The World of Strange and Dangerous Diseases | Comments (0)