Human diseases- causes and symptoms

ISC 12>UNIT 4>HUMAN DISEASES- CAUSATIVE AGENT, SYMPTOMS AND PREVENTION

Communicable diseases causative agent, symptoms and prevention of the following:
bacterial diseases (typhoid and pneumonia), viral diseases (common cold, swine flu and dengue), protozoa (malaria and amoebiasis), helminthes (ascariasis and filariasis);
Sexually transmitted diseases; (gonorrhoea and syphilis)
Non-communicable diseases:
Cancer (types, causes, diagnosis and treatment);
human genetic disorders: (haemophilia, thalassamia, Down’s syndrome, Klinefeltor’s syndrome and Turner syndrome).
Rh factor incompatibility – role of Rh factor in blood transfusion and pregnancy;
Genetic counselling- role of genetic counsellors.
Organ transplants and brief idea of immuno-supressants.
Role of stem cells in medical treatment.

Diseases can be communicable or non communicable.

Communicable diseases are those that are transmitted from one person to the other. These include diseases caused by bacteria, virus, protozoans and helminthes.

Non communicable diseases are those that are not transmitted from one person to the other. These include cardiovascular diseases, diabetes, cancer and genetic disorders.

COMMUNICABLE DISEASES

VIRAL DISEASES

1.COMMON COLD

Causative agent- Rhinovirus
Symptoms-
1.      Nasal stuffiness or drainage
2.      Sore or scratchy throat
3.      Sneezing
4.      Hoarseness, coughing
5.      Headache and fever
Prevention: Use of- hand sanitizers, disinfectants and facial tissues
Treatment: Decongestants for nasal symptoms , Acetaminophen and ibuprofen for headache and fever.

CHICKEN POX

Causative agent: Vericella zoster
Symptoms
1.Skin eruptions as red papules
2.Papules grow into pustules.

Preventive measures-
1.Patients to be isolated till all scabs fall off.
2.Person attending the patient should clean and wash hands with soap
3.Items used by patient should be cleaned and boiled before reuse
4.Patient should be given antiseptic bath.

Treatment: Passive immunity by Zoster Immune Globin

RABIES (HYDROPHOBIA)

Causative agent: Street virus
The virus stimulates then destroys the cells of brain and spinal cord.

Symptoms
1.      Severe headache
2.      High fever
3.      Painful spasm of muscle and throat.
4.      Choking, convulsions and inability to swallow even liquid food.
5.      Feels thirsty but has fear of water

Prevention
1.      Complete immunization of pet dog, cat etc.
2.      Isolation or killing of rabied dogs which become mad due to this virus.

Treatment: Pasteur treatment

POLIOMYLETIS

Causative agent: Polio virus

Symptoms
1.      Affects central nervous system, destroys large motor cells of spinal cord that controls muscular activity.
2.      Limbs gets paralysed

Prevention-
1.      Proper covering of food
2.      Avoid eating food items contaminated by flies.

Treatment:
1.      Poliomyletis vaccine (Salk vaccine)
2.      Oral polio vaccine (OPV)

http://amhistory.si.edu/polio/activities/lifecycle/lifecycle_10.htm

HEPATITIS (Epidemic jaundice)

Causative agent: hepatitis virus
Inflammation of liver

Symptoms
1.      Flue –like symptoms of fever.
2.      Yellowing of skin and sclera
3.      Headache, joint pains.
4.      Loss of appetite, nausea, vomiting
5.      Irritating rashes

Prevention
1.      Contamination of water and food
2.      Sanitary disposal of excreta
3.      Use of boiled or chlorinated water during epidemic

Treatment: Attack gives immunity

2. H1N1 INFLUENZA (HUMAN SWINE FLU/ SWINE FLU)

Causative agent: H1N1 virus

symptoms-

body ache
chills
cough
fatigue
loss of appetite

treatment:
anti-viral medications like

Amantadine
oseltamivir/ zanamivir

Prevention
H1N1 vaccine

3. DENGUE

Causative agent: Dengue virus
Transmitted by the bite of an Aedes mosquito
Symptoms: (which usually begin four to six days after infection and last for up to 10 days)

Sudden, high fever
Severe headaches
Pain behind the eyes
Severe joint and muscle pain
Nausea
Vomiting
Skin rash, which appears three to four days after the onset of fever
Mild bleeding (such a nose bleed, bleeding gums, or easy bruising)

TreatmentFever is treated by anti-pyretics, like paracetamol.
Pain in the bone should be treated by analgesics or pain killing tablets.

BACTERIAL DISEASES

TUBERCULOSIS

Causative agent: Mycobacterium tuberculosis.

Symptoms
1.      Fever
2.      General weakness
3.      Loss of appetite, persistent coughing
4.      Yellowish blood stained sputum

Prevention
1. Isolation of TB patients
2. Health education
3. Vaccination by BCG
Diagnosed by Mantoux reaction
Treatment -Streptomysin, para-amino salicylic acid,rifampicin etc.

1. TYPHOID

Causative agent: Salmonella typhi.

Symptoms
1.      Lesions and damage to the intestinal wall.
2.      Continued fever.
3.      Abdominal tenderness
4.      Headache, and slight vomitting

Prevention:
a.       proper community sanitation
b.      Personal cleanliness
c.       Protection of food and water dust and flies

Treatment
  Ampicillin and chloromycetin

CHOLERA

Causative agent: Vibrio comma or Vibrio cholerae
Symptoms
1.      Acute diarrhoea
2.      Vomitting
3.      Muscular cramps
4.      Stool is white and watery(rice water appearance)
Prevention
1.      Proper heating of food
2.      Boiling of drinking water
3.      Proper disposal of wastes
4.      Prevent contamination of food by flies
Treatment: Replace fluids and electrolytes
Tetracycline or other antibiotics

TETANUS (lock jaw)

Causative agent: Clostridium tetani
On entering the body bacteria produce neurotoxin- tetranospasmin
Symptoms
1.      Painful muscle contractions of neck and jaws.
2.      Increased rigidity of jaws-lock jaw
3.      Painful arching leading to death
Prevention

1. Active immunization incase of cut/injury
2. Antitoxin serum- Human tetanus immunoglobulin (HTIG)
3. The cut surface should be kept properly covered and bandaged to avoid contamination.

Treatment: Human tetanus immunoglobulin neutralizes the toxin Vaccine -DPT

2. PNEUMONIA

Causative agent- Streptococcus pneumonia

·         Infection of lungs

·         Pneumonia is caused by the inhalation of infected microorganisms (tiny, single-celled living organisms, such as bacteria, viruses, fungi or protozoa) spread through contact with an infected person.

·         The microorganisms enter the body through the mouth, nose and eyes.

BACTERIAL PNEUMONIA
Pneumonia-causing bacteria is present in many throats, but when the body's defenses are weakened (for example, by illness, old age, malnutrition or impaired immunity) the bacteria can multiply, working its way into the lungs, inflaming the air sacs and filling the lungs with liquid and pus.

Symptoms
With bacterial pneumonia, the person may experience:

shaking
chills
chattering teeth
severe chest pain
cough that produces rust-colored or greenish mucus
very high fever
sweating
rapid breathing
rapid pulse rate

VIRAL PNEUMONIA
Half of all pneumonias are believed to be caused by viruses, such as influenza (flu), adenovirus, coxsackievirus, chickenpox, measles, cytomegalovirus and respiratory syncytial virus. These viruses invade the lungs and multiply.
Symptoms
With viral pneumonia, the person may experience:

fever
dry cough
headache
muscle pain and weakness

Treatment
Bacterial pneumonia (caused by the streptococcus pneumonia bacteria) is often treated with penicillin, ampicillin-clavulanate (Augmentin) and erythromycin.

Viral pneumonia does not respond to antibiotic treatment. This type of pneumonia usually resolves over time. If the lungs become infected with a secondary bacterial infection, the doctor will prescribe an appropriate antibiotic to eliminate the bacterial infection.

Prevention

Practice good hygiene. Get a pneumonococcal vaccine.
Get a pneumonococcal vaccine.
Practice good preventive measures by eating a proper diet, getting regular exercise and plenty of sleep.
Do not smoke.

DISEASES CAUSED BY PROTOZOANS

1. MALARIA

Causative agent: Plasmodium
Transmitted by bite of female Anopheles mosquito
Symptoms:
1.      High fever with chills
2.      Fever subsides with profuse sweating
3.      Cycle of fever and sweating repeated after 2-3 days
4.      Severe headache
5.      Nausea
Prevention

Fill up ditches, ponds and pools with earth to prevent breeding of mosquitoes
Spray the ponds with kerosene oil or some insecticide to kill the larvae and pupae of mosquitoes.
Cover drains or make underground drain

Treatment: Quinine, mepacrine, chloroquinone etc.
SF- 66 vaccine.

3. AMOEBIASIS

Causative agent: Entamoeba histolytica
Symptoms: 1.      Invade intestinal wall, destroy the mucosa.
2.      Abdominal pain
3.      Nausea
4.      Flatulence
5.      Bowel irregularity with fatigue and headache.
Prevention

Washing hands before taking meals and after toilet
Protection of food and water from flies and cockroach
Proper sanitation
Purification of drinking water

Treatment: Administration of antibiotics like, fumagillin, terramycin.

DISEASES BY HELMINTHES

1. ASCARIASIS

Causative agent: Ascaris lumbricoides
Symptoms: 1.      Indigestion
2.      Abdominal discomforts
3.      Acute colic pain
4.      Appendicitis
5.      Gastric ulcer with diarrhoea and vomitting.
Prevention

Avoid use of raw vegetables and contaminated water
Proper sanitary disposal
Wash hands properly before eating
Proper hygienic measures

Treatment: Adult worm can be removed by mixture of oil of chenopodium and tetrachlorethylene.

2. FILARIASIS (Elephantiasis)

Causative agent: Wuchereria bancrofti
Transmitted by culex mosquito
Symptoms:
1. Lymph vessels are obstructed due to metabolite deposits.
2. Periodic attacks of fever
Prevention

Destruction of mosquitoes
Protection against mosquito bites

Treatment: Diethyl carbamazine, Paramelaminyl phenylstibonate

SEXUALLY TRANSMITTED DISEASES

Sexually transmitted diseases (STDs) are highly infectious, transferred through sexual contact. They are also called general diseases (VD) or reproductive tract infections(RTI).

1.GONORRHOEA

Causative agent: Nisseria gonorrhoea
Symptoms:
1.Infects the mucus membrane of urinogenital tract.
2. genital discharge and painful urination.
Treatment and Prevention:
Effective antibiotics are used for treatment.
Prevention includes- safer sex practices and refraining from sex till the antibiotics are completed.

2. SYPHILIS

Causative agent: Trepanoma pallidium
Symptoms:
1. causes sores and lesions in the genital tract.
2. Burning sensation during urination
3. Later can cause sores in the mouth.
Treatment and Prevention:
Effective antibiotics are used for treatment.
Prevention includes- safer sex practices and refraining from sex till the antibiotics are completed.

NON COMMUNICABLE DISEASES

DIABETES MELLITUS

Diabetes is a condition of the body where the body is unable to use the sugars from the diet due to malfunctioning of islets of Langerhans of pancreas.
As a result of this sugar accumulates in the blood and tissues causing various defects in the body.
Two types – Insulin dependent- deficiency of secreted by islets of Langerhans cells of pancreas.
Non- insulin dependent diabetes- failure of target cells to take up insulin from blood
Symptoms

Glycosuria (glucose in urine)
Hyperglycemia (high glucose level in blood)
Frequent urination
General weakness, tiredness or fatigue
Increased thirst/hunger
Numbness of toes and fingers
Loss of weight
Blurred vision
Reduced hearing capacity
Wounds take longer time to heal.

Prevention

Periodic check ups
Avoid taking starchy and sugary food.

Treatment: Sulphonylureas, glipzide, etc.

DIABETES MELLITUS

Caused due to disturbances in the secretion of insulin from pancreas
There are two types of diabetes mellitus.
This concerned with blood sugar balance.
Symptoms include excessive urination with sugar in the urine.

DIABETES INSIPIDUS

Caused due to disturbances in secretion of vassopressin by posterior pituitary.
Diabetes insipidus do not have any types.
This is concerned with blood water balance.
Symptoms include excessive urination, and no sugar in the urine

CARDIOVASCULAR DISEASES

ANGINA PECTORIS

When the coronory arteries get blocked, the heart muscles do not get oxygen. This results in sharp pain in the heart and chest. This condition is called angina pectoris.

The pain is sharp and usually in the center of the chest and is accompanied by a feeling of suffocation, dizziness and palpitation.
It is not a disease but a symptom of coronary disease.

ISCHEMIA/ MYOCARDIAL ISCHEMIA

Cause- heart muscles are damaged or do not work as efficiently due to a reduced blood supply to the heart.

caused by narrowing of the coronary arteries, a condition called atherosclerosis.

Symptom

chest pain, which can indicate a heart attack (also known as cardiac arrest).
This is felt as a tightening or weighing down of the chest and upper body parts including the neck, jaws, and shoulders.

Prevention

Control Your Diet
Exercise
Avoid Tobacco and Alcohol

HEART ATTACK

A heart attack happens when the flow of oxygen-rich blood to a section of heart muscle is suddenly blocked. If blood flow isn't restored quickly, the section of heart muscle begins to die.
May be caused due to different conditions - rheumatic heart disease, atheroma, atherosclerosis, hypertension coronary sclerosis, coronary thrombosis or Ischemia.
Symptoms
Severe pain in the chest, accompanied by breathlessness, nausea and vomiting.
Prevention-

No smoking- as smoking constricts the blood vessels
Avoid being overweight
Avoid starchy, sugary food after the age of 35
Avoid eating food rich in animal fat
Avoid overwork and stress
Regular exercise is necessary

Coronary sclerosis

1. Narrowing of coronary artery or its branches due to accumulation of fatty substances.
2. Obstructs blood circulation to the heart causing heart attack.

Coronary thrombosis

1. Clot is formed in some part of the coronary artery that cuts off the supply of blood to a part of the heart muscles.
2. This is called myocardial infraction.

Arteriosclerosis

1.      Hardening of the arteries.
2.      Due to old age arteries harden, because of loss in elasticity or deposition of cholesterol.
3.      Causes increased blood pressure leading to rupture of blood vessels of the brain (cerebral haemorrhage) or body (visceral haemorrhage).

Atherosclerosis

1.      Narrowing of arteries
2.      Due to deposition of cholesterol on the lining. Causes clot formation or thrombosis.
3.      If in coronary artery – heart attack
4.      If in brain -- stroke

Heartdiseases

CANCER

Uncontrolled growth of a tissue due to unlimited and uncontrolled mitotic divisions.
NEOPLASM- new growth of unwanted cells.
TUMOR- undifferentiated lumpy collection of cells.
MALIGNANCY- chaotic cells growth that leads into nearby tissues.
MALIGNANT- when tumors becomes cancerous. Spread to distant parts is called metastasis.
BENIGN- when tumors are non-cancerous

DANGER SIGNALS OF CANCER (Diagnostic features):
  1.      Presence of tumor on lip, tongue or breast.
2.      Rapid change in appearance of warts on the body
3.      Persistent changes in the bowel movements.
4.      Hoarseness in voice, coughing difficulty in swallowing.
5.      Continuous bleeding of wound or longer time for healing.
6.      Continuous weight loss
7.      Uncontrolled mitotic division
8.      Cells grow more than normal cells

KINDS OF CANCER

SARCOMAS: malignant growth in bone, muscle, lymph node and connective tissues.

CARCINOMAS: malignant growth of skin, lung, breast, stomach and pancreas.

LEUKEMIA: blood cancer.

Common cancers in India- uterine-cervical cancer and mammary gland cancer in women, mouth and throat cancer in men.

CAUSES AND TREATMENT OF CANCER

Carcinogens –agents that cause cancer Oncogenes- get activated under certain conditions like-
1.      Smoking
2.      Chewing of tobacco
3.      Use of chemicals
4.      Exposure to rays

Treatment:

Surgical removal
Radiotherapy- use of X-rays
Chemotherapy- use of drugs

HUMAN GENETIC DISORDERS

DOWN’S SYNDROME (Mongolian idiocy)

Disorder associated with extra 21 chromosome.
Due to non-disjunction of chromosome 21 during egg formation
Individuals have 47 chromosome (45 + XX or 45 + XY).

Characteristics:

Prominent forehead with round face and flattened nasal bridge.
Mongolian type of eye and gap between first and second toes.
Mentally retarded with malformed heart, children normally die before maturity.

Edward’s syndrome- extra 18 chromosome
Patau’s syndrome- extra 13 chromosome

KLINEFELTER’S SYNDROME
Disorder due to XXY genotype.
Characteristics:

Is a sterile male with underdeveloped testes
Unusually long legs
Obesity
Mental retardation and shows female characters.

TURNER’S SYNDROME

XO genotype
Fusion of abnormal 0 egg with a normal X sperm.
Individuals have 45 chromosomes
Individual is sterile female

Characteristics-

Short stature
Underdeveloped breasts
Reduced ovaries, small uterus
Webbed neck
Subnormal intelligence.

HAEMOPHILIA

Also called bleeders disease
Mostly restricted to males only
Even a small injury results in bleeding leading to death.
It is an X linked recessive disorder and is expressed in males.

ALBINISM

Albinism is a defect of melanin production.
This defect results in the partial or full absence of pigment (color) from the skin, hair, and eyes.
Characteristics

- Absence of pigment from the hair, skin, or iris of eyes
- Patchy absence of pigment (skin color, patchy)
- Lighter than normal skin and hair

THALASSAEMIA

Rh INCOMPATIBILITY

Develops due to incompatibility of gene products in the blood. Two well known incompatibilities are ABO blood group and Rh factor.

ABO incompatibility

With an ABO incompatibility, a mother makes antibodies against her baby's blood type. It doesn't happen if the mother and baby have the same blood type or if the baby is type O, since in that case, there is usually nothing to make antibodies against. These antibodies, if the mother is type O, can cross the placenta and can break down the baby's red blood cells after she is born, leading to jaundice and anemia. This condition is called Hemolytic Disease of the Newborn or erythroblastosis fetalis, and it can also be caused by having an Rh incompatibility between a baby and mother. If a mother is type A or B and the baby has a different blood type other than type O, she can still make antibodies against the baby's red blood cells. These antibodies are too large to cross the placenta though, and so don't usually lead to any problems.

Rh factor incompatibility

Clinically, the Rh factor, like ABO factors, can lead to serious medical complications. The greatest problem with the Rh group is not so much incompatibilities following transfusions (though they can occur) as those between a mother and her developing fetus. Mother-fetus incompatibility occurs when the mother is Rh- and her fetus is Rh+ . Maternal antibodies can cross the placenta and destroy fetal red blood cells.

AMNIOCENTESIS

Amniocentesis is a procedure used to obtain a small sample of the amniotic fluid that surrounds the fetus during pregnancy. Amniotic fluid is a clear, pale yellow fluid made by the fetus. The fluid protects the fetus from injury and helps to regulate the temperature of the fetus.

An amniocentesis may be used for genetic and chromosome testing in the second trimester of pregnancy in the presence of one or more of these conditions:

Family history or previous child with a genetic disease or chromosomal or metabolic disorder
Risk of open neural tube defects (ONTDs), such as spina bifida
Maternal age over 35 years by the pregnancy due date
Abnormal maternal screening tests, such as maternal serum alpha fetoprotein level (MSAFP)
Risk of a sex-linked genetic disease

GENETIC COUNSELING

(the term was introduced by Sheldon Reed.)
The area of health care that offers advice on genetic problems is called genetic counseling.
It uses different techniques for determination of the actual disease.

Role of genetic counselors.
Educates common man of the dangers of hereditary diseases and various genetic malformations.
Help in educating general public about the use of various information, that is revealed by scientific exploration.
Genetic counselor can predict the characteristics of future generations and can help in planning parenthood.
The geneticist can tell the probability of producing infected offspring by studying pedigree charts of couples.
Suspected errors of metabolism can be identified.