PBL 7: Viral diseases

Question 1

Describe the range of common viral infections seen in primary care

Answer 1

range of common viral presentations:
URTI - Upper respiratory tract infection → Any infection that involves the nasal cavity, paranasal sinuses, pharynx, or larynx, and it’s most often caused by an invading pathogen like a virus.
Viral Exanthem
Warts → typically small, rough, hard growths that are similar in colour to the rest of the skin, typical in Human Papillomavirus
Diarrhoea +/- Vomiting
Acute Viral Jaundice → Yellowing of the skin due to too much bilirubin in the blood
Screening Results
Immunocompromised → Commonly seen in AIDs

Human herpes viruses - Generally, HSV1 → Above the waist HSV2 → Below the waist
Human Papilloma Viruses - affect epithelial cells,
Parvovirus B-19 - “Slapped Cheek Syndrome” Children 6-10 years old Can cause serious illness in sickle cell anaemia and HIV
Adenovirus - Sore Throat, Nasal Congestion, Dry Cough, Conjunctivitis, Nausea, Vomiting, Diarrhoea, Fever, Malaise, Headache and myalgia
Parainfluenza - Coryza, Cough and Mild Fever. Barking Cough, Hoarseness, Respiratory Distress, Agitation, Symptoms worse at night
Dengue - High Grade Fever, Generalised Pain, Nausea, Vomiting, Rash. Not in the UK
Rhinovirus - Cough, Coryza, Rhinorrhoea, Sore Throat, Myalgia, Fatigue. Headache, Anorexia and Fever
Coxsackie A-16 - Hand, Foot and Mouth Disease
Norovirus - faecal-oral route, very contagious, vomiting and watery diarrhoea
Rotavirus - “Stomach Flu” Acute onset vomiting and Watery Diarrhoea
Molluscum contagiosum - Dome Shaped Shiny Umbilicated Papules (2-5mm), Lesion Distribution, Molluscum Dermatitis and Eyelid Lesion
Hepatitis A and E - Hand Foot and Mouth Disease Herpangina
Hepatitis C - Chronic → Asymptomatic. Acute → Mild fatigue, nausea, decreased appetite, joint and muscle pain.
Mumps - Prodrome, Parotitis, Mastitis.
Rubella - Maculopapular Rash. Lymphadenopathy, Mild Nonexudative Conjunctivitis. very rare

Question 2

Discuss what health economic techniques can be used to inform the decision as to whether a particular treatment is available on the NHS.

Answer 2

Health economics: Allocating healthcare resources under conditions of scarcity of resources and to obtain maximum value for money

Economic evaluation: The comparative analysis of alternative interventions in terms of both their costs and consequences.

Perspective can alter the results of economic evaluation:

Societal viewpoint: all relevant costs associated with treatment and illnesses should be identified, quantified and evaluated
NICE guideline viewpoint: the perspective adopted on costs should be that of the NHS, personal and social services

Need to systematically compare the costs and benefits of at least 2 treatments to evaluate the best use of scarce resources

Types of economic evaluation:

Cost-effectiveness analysis (CEA):
- compares costs (monetary units) and health effects (non-monetary units) of competing interventions
- compares in cost per unit of effectiveness

Cost-benefit analysis (CBA)
- In a cost–benefit analysis, all individual benefits are measured in monetary terms, meaning all costs and consequences are measured in the same units.
- used when information is required on which interventions lead to overall resource savings

Used when: lots of outcomes that are hard to compare associated with the interventions being compared

Cost-utility analysis (CUA)
- Utility measurements (common quality of life outcomes) are combined with survival estimates to generate quality-adjusted life years (QALYs) - a year spent in a particular health state and the utility measurement for that health state

Used when: the quality/quantity of life is the main outcome of the intervention

Cost-minimisation analysis (CMA)
- measures all costs necessary to the delivery of an intervention

Used when: health outcomes between competing interventions is similar if not identical

Question 3

Define homeostasis and describe the homeostatic control of temperature

Answer 3

Homeostasis → biological systems maintain the body’s internal environment within a range of values suitable for life, while adjusting to changing external conditions

• The main mechanism to maintain a homeostatic environment → negative feedback
  
  • Negative feedback → body senses changes and activates mechanisms that reverse it
  • Positive feedback → body senses change and continues in the same direction e.g. breast feeding
• Normal temp → 37°C± 0.5°C
  
  • 38.5°C + → Hyperthermia
  • 35°C - →Hypothermia

Central thermoafferents are warm sensing.
Peripheralthermoafferents are cold sensing. They quickly detect change in temp and allows the body to adapt before core temp drops.

Fever causes body temp conservation thresholds to change, e.g shivering to raise temp, sweats to bring it back down

Question 4

Describe how vaccines and immunisation work and compare different types of vaccines

Question 5

Describe the main classes of viruses causing human disease and the mechanism by which viruses cause infection

Question 6

Describe the management of needlestick injuries and the pathogens that can be transmitted

Question 7

Discuss the common and important viral diseases