PATHOPHYSIOLOGY

UNIT-5

IMPORTANT Questions

1. Discuss the pathophysiology of AIDS and its complications. (STDs)

2. Write a detailed note on tuberculosis (Tb).

3. Write a detailed note on UTI (Urinary Tract Infections).

4. Write a note on:-

   I. Meningitis
   II. Typhoid
   III. leprosy
   IV. Syphilis.

STDs

• STDs, or Sexually Transmitted Diseases, are infections that can be spread through sexual contact.
• They are usually spread through vaginal, anal, or oral contact and can be caused by bacteria, viruses or parasites.
• Examples of STDs including HIV/AIDS, Syphilis, Gonorrhea, chlamydia etc.
• It's important for sexually active individuals to get tested regularly and prevent safe sex to prevents the spread of STDs. (important to seek medical attention).
• According to WHO, more than a million of people acquire a STD every day and the number is increasing day by day.
• majority of infections arise in young adults (up to 25 year of age).

AIDS

ACQUIRED IMMUNO-DEFICIENCY SYNDROME

• AIDS is one type of STDs (sexually transmitted Disease). firstly recognised in 1981.
• AIDS is a chronic and life-threatening conditions caused by Human Immunodeficiency Virus (HIV).
• It is the most advanced stage of HIV infections, which damages the immune system and makes the body risks to opportunistic infections and cancers.

STAGES OF HIV INFECTIONS

• The initial stage of primary infections occurs within weeks of acquiring the virus, characterised by flu-like illness that resolves within weeks.
• Chronic Asymptomatic infections, a long duration of infections without symptoms lasts for 8-10 year, but can still transmit the virus to others.
• Then symptomatic (show some symptoms, such as fever, fatique, weight loss).
• Then AIDS, it is the most advanced stage, severely weakened immune system and then chances of opportunistic infections.

ETIOLOGY

• HIV (Human immunodeficiency Virus) a retrovirus that attacks and weakens the immune system.
• HIV transmission (through sexual contact, blood transfusion, mother to child)
• Genetic factors (from parents)
• weakened immune system
• low CD4 cell counts (below 200 cells/$mm^3$)

RISK FACTORS

• Unprotected sex
• Multiple sexual partners.
• contamined needles/syringes
• Blood transfusion/organ transplant

NOT SPREAD THROUGH

• Casual contact (Hugging, shaking hands, sharing foods).
• Air/water
• Insect bites
• Saliva, sweat, tears (unless + blood).

HIV

• It is an enveloped RNA virus.
• It contains phospholipid envelope.
• Each peg consist of 3-4 gp41 glycoproteins, capped with 3-4 gp120 glycoproteins.
• Inside envelope, it contain bullet-shaped nucleocapsid of virus made up of proteins and surrounds two single strands of RNA.

TYPES

1. HIV-1: most common form of virus, responsible for majority in worldwide.

2. HIV-2: less infectious and less severe than HIV-1, most common in west central Africa, parts of Europe and India.

SIGN AND SYMPTOMS

• fever
• fatique
• weight loss
• Muscle aches
• Joint pain
• Night sweats
• Diarrhea
• Coughing
• shortness of breath
• Others $\rightarrow$

OTHERS

• Lymphadenopathy (enlargement of lymph node)
• Kaposi's sarcoma (cancer) > 60 yr old
• Lymphoma cancer affects the immune system
• various infections etc_

COMPLICATIONS

• AIDS - most advanced stage of HIV infections.
• These complications can be life-threatening, if left untreated.
• Pneumocystic pneumonia $\rightarrow$ A fungal infection that cause inflammation in lungs.
• Toxoplasmosis $\rightarrow$ A parasitic infection that affects the brain, eyes & other organs.
• Kaposi's sarcoma $\rightarrow$ A type of cancer that cause tumors to form in the skin, lymph nodes and other organs.
• Lymphoma $\rightarrow$ A type of cancer that affects the immune system.
• Tuberculosis $\rightarrow$ A bacterial infection that affects the lungs & other organs.
• Candidiasis $\rightarrow$ A fungal infection that causes yeast infections in the mouth, throat and vagina.
• wasting syndrome $\rightarrow$ A condition characterized by significant weight loss and muscle wasting.
• Others $\rightarrow$ Infections, Cardiovascular disease, cancer, Pulmonary disease, Bone disorders etc..

PATHOGENESIS

DIAGNOSIS

• HIV antibody tests
• Viral load tests
• CD4 cell count

TREATMENT

• Antiretroviral therapy
• Cancer treatment
• Supportive care
• Precaution from risk factors/causes.

TUBERCULOSIS (TB)

• It is an infectious disease caused by the bacteria Mycobacterium tuberculosis.
• This bacteria usually attack the lungs, but they can also damage other parts of body such as brain, kidney etc..
• TB spreads through the air when a person with active TB infection cough, sneezes, spit, close contact talk.

TYPES

• Latent TB infections: The bacteria remain in the body, but the person is not infectious.

• Active TB disease: The bacteria multiply and cause symptoms, making the person infectious.

ETIOLOGY

• It is caused by bacteria, Mycobacterium tuberculosis. (small, aerobic, non-motile bacillus, divides 16-20 hours)
• Close contact with TB infected person.
• weakened immune system (e.g. HIV/AIDS, Cancer, Immunosuppressive drugs).
• Age (elderly/young children)
• Poor living condition.
• Malnutrition

SIGN AND SYMPTOMS

• Coughing for three or more weeks (chronic cough)
• Coughing up blood-containing mucus.
• Chest pain or discomfort.
• fatique
• weight loss
• fever
• Night sweats
• Chills

PATHOGENESIS

COMPLICATIONS

• Extrapulmonary spread (TB in other organs)
• Respiratory failure
• Meningitis
• Spinal Joints, Joint damage
• Blurred vision
• Liver or kidney affects

TREATMENTS

• Prevention - Vaccination, mask, avoid contact
• Anti-tubercular drugs - Isoniazid, rifampicin, Para amino salicylic acid etc..
• proper nutritions etc..

UTIs

URINARY TRACT INFECTIONS

• It is an infections that affects the urinary tract and its parts i.e.

  • Ureters
  • Bladder
  • Urethra.
  • Kidney

• It is mostly caused by a bacteria (E. coli) approx. 90%. then Staphylococcus saprophyticus.

• It is most common in womens than man i.e. 8:1 ratio.

TYPES

1. Lower UTIs: It affects urethra (urethritis) and Bladder (cystitis). It is most common and less severe.

2. Upper UTIs: It affects ureters and kidney (pyelonephritis). It is more severe life-threatening conditions.

ETIOLOGY

• It is mostly caused due to bacteria Escherichia coli (E. coli) $\rightarrow$ around 90% cases
• Genetic factors (family history)
• Drug induced factors (e.g. Antibiotics).
• Poor hygiene (improper wiping, contaminated clothes)
• Sexual intercourse
• Medical conditions (e.g. diabetes, kidney stones etc).

SYMPTOMS

• Lower UTIs
  • Burning sensation while urinating
  • frequent urination/ urge to urinate
  • cloudy or strong-smelling urine.
• Upper UTIs
  • fever, Chills
  • Nausea and vomiting
  • Pain in back or side (pelvic/rectal pain).

PATHOGENESIS

COMPLICATIONS

• Recurrent UTIs
• Kidney damage/failure
• Blood poisoning/infection septicemia
• Premature birth (pregnancy)

TREATMENTS

• Maintain good hygiene
• staying hydrating (drink water)
• Medications
• Antibiotics - Ciprofloxacin, fluconazole etc..

MENINGITIS

• It is an inflammation of the meninges, the protective membrane made up of connective tissue that covers the brain and spinal cord.
• It is caused by bacterial, viral, parasite or fungal infections.
• In meningitis, the meninges become inflamed $\downarrow$ Swelling & pressure on brain/s.c $\downarrow$ Disruption of blood flow/$O_2$ $\downarrow$ damage to brain tissue.

ETIOLOGY

• Bacteria $\rightarrow$ Neisseria meningitides, M. tuberculosis, Streptococcus pneumoniae (pneumococcus), H. influenzae

• Virus $\rightarrow$ Enterovirus (echovirus), HIV, Herpes simplex virus (HSV)

• Fungi $\rightarrow$ Cryptococcus neoformans, candida species etc..

SYMPTOMS

• Sudden onset of fever
• Sever headache
• Vomiting
• stiff neck (nuchal rigidity)
• Confusion
• Sensitivity to light (photophobia)

COMPLICATIONS

• Hearing loss
• Learning disabilities
• Impaired memory
• Seizures
• Hydrocephalus (fluid accumulation in brain)
• kidney failure
• shock
• Death

PREVENTION/TREATMENTS

• Vaccines (e.g. meningococcal conjugate vaccines)
• Good hygiene practices
• Avoid close contact with meningitis patients.
• Antibiotics, Antiviral & Antifungal drugs.

DIAGNOSIS

• Physical examination
• Lumbar puncture
• Blood culture, CT Scan, MRI

PATHOGENESIS

TYPHOID

• Typhoid fever is a bacterial infection caused by the bacterium Salmonella typhimurium (S. typhi). Also termed as Enteric fever.
• It is usually spread through contaminated food and water.
• It mainly occurs in the intestines and blood of humans.

ETIOLOGY

• It is caused by a bacteria Salmonella typhi (a gram negative bacterium)
• It can spread through:
  • Contaminated food and water (through faeco-oral route)
  • direct contact with infected person's feces or urine

RISK FACTORS

• Poor sanitation and hygiene
• Contaminated water supply
• Crowded living conditions
• Lack of vaccination.

SYMPTOMS

• fever (High temperature upto $104^\circ F$)
• Headaches
• Loss of appetite
• fatigue (feeling weak)
• Muscle aches and pain
• Abdominal pain
• Chest congestion
• Diarrhoea/constipation

PATHOGENESIS

COMPLICATIONS

• Perforation of intestine
• Intestinal bleeding
• infections of other organs (Kidney, liver, spleen)
• Meningitis (rare case)

DIAGNOSIS

• Blood culture
• Widal test (antibody)
• Stool test

PREVENTION

• Vaccinations (for travelers/high risk group)
• safe drinking water
• Avoid close contact with infected peoples.

TREATMENTS

• fluid replacement
• Antibiotics (e.g. Ceftriaxone, azithromycin)
• Rest

LEPROSY

• Also known as Hansen's disease.
• It is a chronic infectious disease, caused by the bacteria Mycobacterium leprae.
• It affects the nerves, skin, and mucous membrane.

ETIOLOGY

• It is caused by mycobacterium leprae, a slow-growing, acid-fast bacillus.
• It is transmitted /spread through respiratory droplets from infected persons, close contact and broken skin.

RISK FACTORS

• close contact with an infected person.
• Poor sanitation and hygiene.
• weakened immune system
• Genetic susceptibility
• Age (more common in children & young adults)
• Poverty
• malnutrition

SYMPTOMS

• Skin lesions or patches with loss of sensation.
• Numbness in affected areas.
• Pale or red patches on skin.
• Eye problems (dryness, vision loss, ulcers)
• Nerve damage
• thick, stiff, or dry skin
• Severe pain

COMPLICATIONS

• Permanent nerve damage
• Hair loss (on eyebrows / eyelashes)
• Muscle weakness
• Disability in hands & feets
• Glaucoma, Blindness
• erectile dysfunction (infertility)

DIAGNOSIS

• Skin biopsy
• Slit-skin smear test
• Lepromin test
• Clinical diagnosis (Cuts, wounds, skin lesions)

PATHOGENESIS

PREVENTION

• Vaccination (BCG Vaccines)
• Early detection & treatment

TREATMENT

• Antibiotics (rifampicin, clofazimine, dapsone)
• Multidrug therapy.

GONORRHOEA

• It is a sexually transmitted infections (STIs/STDs) caused by the bact

ETIOLOGY

• Caused by Treponema pallidum
• Spread through sexual intercourse, Blood transfusion, mucous contact.

SYMPTOMS

• Painless ulcer or sore (chancre) appears at site of infection (genitals, rectum, mouth)
• Sore throat
• fever
• fatique
• Headache
• Hair loss, Joint pain
• Neurological problems (In advanced stages)

PATHOGENESIS

COMPLICATIONS

• Small bumps/tumours
• Neurological problems
• Cardiovascular problem

TREATMENT

• Safe sex + Avoid contact with infected persons
• Antibiotics (e.g. penicillin)

GONORRHOEA

• It is a sexually transmitted Infections (STIs/STDs) caused by the bacterium Neisseria gonorrhoeae.
• It is transmitted through sexual contact (vaginal, and or oral) and also from mother to child during childbirth.

SYMPTOMS

Females

• Abnormal vaginal discharge
• Burning sensation during urination
• Abdominal pain
• Bleeding b/w periods

Males

• Discharge from penis
• Painful urination
• Painful swelling of testicles

ETIOLOGY

• caused by bacteria Neisseria gonorrhoeae.

PATHOGENESIS

COMPLICATIONS

• Pelvic inflammatory disease (PID)
• Infertility
• Increased risk of HIV transmission
• Meningitis

TREATMENTS

• Safe sex practices
• Regular testing
• Avoid sexual contact during symptoms
• Medications
• Antibiotics (ceftriaxone and Azithromycin)