Incidence and Prevalence

Dear people,
If u wanna know more about the epidemiology of malignant melanoma, please do visit the links below. They are superb.


Reference
http://emedicine.medscape.com/article/1100753-overview

http://www.skincancer.gov.au/internet/skincancer/publishing.nsf

http://www.nzma.org.nz/journal/119-1242/2169
http://www.enhis.org/object_document/o4731n27388.html

Benign and Malignant Tumour

Benign and Malignant Tumour
Tumours are abnormal growths in your body. Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumour. Tumours can be benign or malignant. Benign tumours aren't cancer while malignant ones are. Cells from malignant tumours can invade nearby tissues. They can also break away and spread to other parts of the body.

Benign Tumour
Also called: Benign cancer, Benign neoplasms, Noncancerous tumours

Benign tumours are not cancer:
• Benign tumours are rarely life-threatening.
• Generally, benign tumours can be removed, and they usually do not grow back.
• Cells from benign tumours do not invade the tissues around them.
• Cells from benign tumours do not spread to other parts of the body.
Treatment often involves surgery

Malignant Tumour
Also called: Carcinoma, Malignancy, Neoplasms, Tumour

Malignant tumours are cancer:
• Malignant tumours are generally more serious than benign tumours. They may be life-threatening.
• Malignant tumours often can be removed, but sometimes they grow back.
• Cells from malignant tumours can invade and damage nearby tissues and organs.
• Cells from malignant tumours can spread (metastasize) to other parts of the body. Cancer cells spread by breaking away from the original (primary) tumour and entering the bloodstream or lymphatic system. The cells can invade other organs, forming new tumours that damage these organs. The spread of cancer is called metastasis.

HOWEVER, not all cancers are in the form of tumours. For example, leukaemia is a cancer of the bone marrow and blood.

Difference between benign and malignant tumours

The two important differences between benign and malignant tumours are invasion and spread.
• As they grow benign tumours simply push the surrounding normal tissues and organs out of their way. Sometimes pressure from a benign tumour may damage surrounding structures but the benign tumour never actually invades into those structures. By contrast malignant tumours eat into and destroy the normal tissue around them as they increase in size. This means that in some parts of the body benign tumours can grow quite large without causing any problems whereas a malignant tumour damages the tissue around it from the time it first begins to grow.
• Benign tumours do not spread. They may grow to a large size but they do not go to other parts of the body. Malignant tumours have the ability to spread by sending off seedlings of tumour which can pass through the blood or lymphatic system to other parts of the body. These seedlings then settle in other organs and form what are called secondary tumours or metastases.Whilst all malignant tumours have the ability to spread, different tumours vary in the speed with which they do so.
• The difference between benign and malignant tumours has nothing to do with frequency - in some organs of the body benign tumours are much more common than cancers, nor does it have anything to do with size, some benign tumours can be very large whilst many cancers are quite small.
•The different types of benign and malignant tumours behave in different ways but the fundamental rule that benign tumours never invade or spread always applies

Confirmatory test
• Doctors can tell if a tumour is benign or malignant by examining a small sample of cells under a microscope. This is called a biopsy.
• First, Imaging
• Imaging can be used to find out where a cancer is located in the body, if it has spread, and how much is present. E.g. ultrasound, MRI, or PET/CT CT scans
• Then, Biopsy (removal of a small piece of tissue for lab exmination) / Tissue sampling
E.g. Fine-needle aspiration, Core needle biopsy, Vacuum-assisted biopsy, Image-guided biopsy

How the Test is Performed
There are several different types of biopsies.
A needle (percutaneous) biopsy removes tissue using a hollow tube called a syringe. A needle is passed through the syringe into the area being examined. The surgeon uses the needle to remove the tissue sample. Needle biopsies are often done using x-rays (usually CT scan), which guide the surgeon to the appropriate area.

An open biopsy is a surgery that uses general anesthesia. This means you are asleep and pain-free during the procedure. The procedure is done in a hospital operating room. A surgeon makes a cut into the affected area, and the tissue is removed.
Closed biopsy uses a much smaller surgical cut than open biopsy. A small cut is made so that a camera-like instrument can be inserted. This instrument helps guide the surgeon to the appropriate place to take the sample.

How to know whether the tumour is malignant or benign

 The overall size and shape of cancer cells are often abnormal. They may be either smaller or larger than normal cells.

 The size and shape of the nucleus of a cancer cell is often abnormal. Cancer cells typically have a nucleus that is larger than that of a normal cell. And, like the overall cell size and shape, the size and shape of the cell nucleus is generally similar among normal cells of each tissue but can vary greatly among cancer cells. Another feature of the nucleus of a cancer cell is that it appears darker when seen under a microscope after being stained with certain dyes. The nucleus from a cancer cell is larger and has a darker shade because it often contains too much DNA.
 Cancer cells do not relate to each other normally. Sometimes the cancer cells form abnormal or distorted glands. Sometimes they form cell clumps that do not look like glands at all. Another feature that shows abnormal interactions by cancer cells is that cancer cells invade other tissues. Normal cells stay where they belong within a tissue.

Risks
• Bleeding
• Infection

LINKS
http://www.nlm.nih.gov/medlineplus/cancer.html
http://www.insidecancer.org/
http://www.cancerbackup.org.uk/Aboutcancer/Whatiscancer/Whatiscancer
http://www.nlm.nih.gov/medlineplus/benigntumors.html
www.nlm.nih.gov/medlineplus/ency/article/003416.htm
http://www.mayoclinic.com/health/biopsy/ca00083
http://www.cancer.org/docroot/ped/content/ped_2_3x_testing_biopsy_and_cytology_specimens_for_cancer.asp?sitearea=ped

SUMMARY-Nobody Is Immune

Summary-Nobody Is Immune(PCL WEEK 8)

1) Immune system

(A network of cells, tissues, and organs that work together to defend the body against attacks by pathogens)

First line of defence (Skin, Lysozyme, Clotting of blood, Mucus and cilia)

Second line of defence (innate immune system (non-specific) and adaptive immune system (specific); Involves leukocytes)

Immunity (Active and passive; Natural and Artificial)

Herd Immunity

If immunity rates in a society is high, then protection will aslo be conferred to those who are unvaccinated.

2) Pertussis

i) Incidence & Prevalence

According to age (US):

2001-2003

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1-4 years – 12 %

5-9 years - 9%

10-19 years – 33%

20 years - 23%

In Malaysia

Decrease after introduction of vaccine

0.02 per 100 000 population. (2006)

ii) Causes & Predisposing factors

Caused by a bacteria called Bordatella pertussis

Predisposing factors: Direct/Indirect Contact, Airbone droplets, Not being immunized.

iii) Pathophysiology
-Typically attacks children
-3 stages : Catarrhal àParoxysmalàConvalescent
Pathophysiology :
-Bordetella pertussis attaches to and multiplies on the respiratory epithelium. This damages ciliated respiratory epithelium.
-The damage starts in the nasopharynx and ends primarily in the bronchi and bronchioles
-Cilia is attacked by bacteria and with the accumulation of debris in the respiratory tract, mucus is produced
-As the body can’t get rid of the mucus in the airways, coughing and inhalation with a whistling or whooping sound entails.
-This causes difficulty in breathing
Whistling/whooping sound :
-Narrowing of the lower respiratory tract and is caused by mucus
-Air moves through the narrowed space, it sounds like whistling or whoosing.
-Often comes from the small breathing tubes (bronchial tubes) deep in the chest

iv) Complications & Symptoms

The first stage- runny nose, sneezing, low-grade fever, mild, occasional cough, similar to the common cold.

The second stage-Bursts (paroxysms) , breathing in accompanied by a characteristic high-pitched "whoop" sound, individual may become cyanotic (turn blue) from lack of oxygen, Children and young infants appear especially ill and distressed, Vomiting and exhaustion

The third stage -The cough becomes less paroxysmal and usually disappears

Complications -secondary bacterial pneumonia,seizures,encephalopathy,reactive airway disease,dehydration,malnutrition.

v) Differential Diagnosis

1. Asthma

Pertussis is also associated with vomiting and sputum. To confirm whether it is asthma or pertussis a definitive culture diagnosis or blood-work is done.

2. Pneumonia

Pertussis is not asscociated with joint pains and shaking chills. Hence, pneumonia is ruled out.

3. Tuberculosis

Lupus vulgaris and chroiditis is not associated with the symptoms of Pertussis. Hence Tuberculosis is ruled out.

4. Febrile Seizures

Pertussis is not associated with otitis media. Hence, Febrile seizure is ruled out.

Diagnosis:

Suggested clinically by the the characteristics of the whooping cough and a history of contact with an infected individual. It is confirmed by the isolation of the organism. Cultures or swabs of nasopharyngeal secretions result in a higher positive yield than cultures of ‘cough plates’.

Workup

Laboratory Studies - Blood work, Cultures, Direct fluorescent antibody (DFA) studies, Enzyme-linked immunosorbent assay (ELISA), Imaging Studies.

vi) Management & Treatment

Medical Care

· The goals of therapy include limiting the number of paroxysms, observing the severity of cough, providing assistance when necessary, and maximizing nutrition, rest, and recovery.

· Hospitalization-Monitor heart rate, respiratory rate, and oxygen saturation of hospitalized patients continuously, especially in relation to coughing paroxysms. Coughing, feeding, vomiting, and weight changes should be recorded.

· Pay attention to the young infant's hydration and nutritional status.

· Patients who are severely ill may require treatment in an ICU.

Medication - Antimicrobial agents, Pertussis-specific immune globulin ,Antibiotics(oral (PO) erythromycin, macrolide antibiotics(erythromycin, clarithromycin, and azithromycin, trimethoprim-sulfamethoxazole).

vii) Prevention – Maintain hygiene, Avoid contact with infected people, Isolation, Vaccination and Booster vaccination, Education.

3)Safety of vaccination & Immunisation schedule

1) Greatest success story in public health: reduction of infectious diseases resulting from the use of vaccines.
eg. Reduced preventable infectious diseases (measles, pertussis, diphtheria)

2) Prior to approval by FDA, vaccines are tested extensively by scientists to ensure they are effective and safe. But no vaccine is 100% safe or effective. (depends on individual immune systems)
- Mice, guinea pigs, rabbits, monkeys
- FDA approves clinical studies
- Human subjects (voluntary), computers used to predict how the vaccine will interact with the immune system
- 3 phases: small (20-100 volunteers) a few months,
larger (several hundred volunteers) months to years,
larger still (several hundreds to thousands) several years.

3) Agencies involved in vaccine safety regulation:
a) National Vaccine Program Office (NVPO) under National Childhood Vaccine Injury Act (NCVIA)
- Vaccine Adverse Event Reporting System (VAERS) by CDC and FDA in 1990
- National Vaccine Injury Compensation Program (NVICP)
b) Department of Health and Human Services (DHHS)
- Centers for Disease Control and Prevention (CDC),
- Food and Drug Administration (FDA)
- National Institutes of Health (NIH)
- Health Resources and Services Administration (HRSA).

4) Six Common Misconceptions By CDC 29 May 2007

Immunization Schedule (2007)

BCG (birth), DtaPHibHep(2,3,5 months), DTwPHib(2,3,5,18 months), HepB(birth,2,3,5 months),IPV(2,3 months), JapEnc(9,10,18 months;5,8,11,14 years), Measles ( 6months), MenACWY (Hajj Pilgrims), MMR(12 months;7 years), OPV (2,3,5,18 months; 7 years), TT(15 years), Typhoid(food handlers), YF (visitors to Yellow fever endemic countries)

4)Role of parents and government on protecting infectious diseases(Covered in Mock-Trial)

Role of Government:

· monitoring, analysing and reporting on vaccine preventable diseases (VPDs) as well as bacterial, bloodborne and sexually transmitted diseases

· providing timely, accurate and relevant surveillance advice to inform policy and response activities relating to VPDs, including pandemic planning

· providing stakeholders with information on the impacts that VPDs and other communicable diseases could pose to Australia, including through cross-jurisdictional and international trend analysis

· managing and contributing to committees on VPD and other communicable disease issues

· engaging data providers and stakeholders to enhance collection and collation of VPD information.

Role of family:(maintain hygiene, immunization, nutrition, healthy lifestyle)

5)Legal & social implications on not getting child immunised(Covered in Mock-Trial)

· Patients autonomy, Children and Young Persons Act 1933, Assessment of vaccination, Herd Immunity

Safety of Vaccination

Vaccine Safety - Introduction

1) Greatest success story in public health: reduction of infectious diseases resulting from the use of vaccines.
a) Eradication of smallpox
b) Near elimination of wild polio virus
c) Reduced preventable infectious diseases (measles, pertussis, diphtheria)

2) During the last 10 years, the FDA has recalled only three vaccine lots: one was mislabeled, another was contaminated during production, and the third was recalled after the FDA discovered potential manufacturing problems at a production plant.

3) Prior to approval by FDA, vaccines are tested extensively by scientists to ensure they are effective and safe. But no vaccine is 100% safe or effective. (depends on individual immune systems)
- Mice, guinea pigs, rabbits, monkeys
- FDA approves clinical studies
- Human subjects (voluntary), computers used to predict how the vaccine will interact with the immune system
- 3 phases: small (20-100 volunteers) a few months,
larger (several hundred volunteers) months to years,
larger still (several hundreds to thousands) several years.

4) Agencies involved in vaccine safety regulation:
a) National Vaccine Program Office (NVPO) under National Childhood Vaccine Injury Act (NCVIA)
- Vaccine Adverse Event Reporting System (VAERS) by CDC and FDA in 1990
- National Vaccine Injury Compensation Program (NVICP)
b) Department of Health and Human Services (DHHS)
- Centers for Disease Control and Prevention (CDC),
- Food and Drug Administration (FDA)
- National Institutes of Health (NIH)
- Health Resources and Services Administration (HRSA).

5) In the last decade, numerous changes in vaccine production and administration have reduced the number of side effects and resulted in safer vaccines. (e.g A more purified acellular pertussis (aP) vaccine has been licensed for use and has replaced the whole cell pertussis vaccine used in DTP (diphtheria, tetanus, pertussis vaccine) – less mild and serious side effects.)


Six Common Misconceptions By CDC 29 May 2007 (will be explained)

1) Diseases had already begun to disappear before vaccines were introduced, because of better hygiene and sanitation.
2) The majority of people who get disease have been vaccinated.
3) There are "hot lots" of vaccine that have been associated with more adverse events and deaths than others. Parents should find the numbers of these lots and not allow their children to receive vaccines from them.
4) Vaccines cause many harmful side effects, illnesses, and even death - not to mention possible long-term effects we don't even know about.
5) Vaccine-preventable diseases have been virtually eliminated from the United States, so there is no need for my child to be vaccinated.
6) Giving a child multiple vaccinations for different diseases at the same time increases the risk of harmful side effects and can overload the immune system.

References:
http://www.who.int/immunization_safety/aefi/immunization_misconceptions/en/print.html
http://www.cdc.gov/vaccines/vac-gen/6mishome.htm
http://www.cdc.gov/vaccines/vac-gen/side-effects.htm#dtap