Immune System Flashcards
Humoral defects
Susceptible to what bacteria, viruses, protozoa
Bacteria
Staph, strep, haemophilus influ, moraxella catarrhalis
Viruses: enteroviruses
Protozoa: Giardia
Cellular immunity
Susceptible to what organisms
Bacteria: Mycobacterium, listeria spp
Viruses: CMV, HSV, measles, RSV adenovirus
Fungi: Candida, aspergillus
Protozoa: Pneumocystis
Neutrophil defect
What organisms typically cause disease
Gram +, gram -
Aspergillus, candida
Complement defects
What organisms
Neisseria
Staphylococcus
Viral causes of encephalitis
Frequent
Rare
Enterovirus HSV 1 and HSV 2 Varicella zoster Measles, mumps Influenza
Rare: adenovirus, rubella, EBV, arenaviruses (japanese B encephalitis), rabies, mycoplasma
Role of steroids in meningitis
Improves deafness in Hib meningitis
Lowers mortality in Step pneumoniae meningitis ( no effect seen in neisseria or Hib subgroups)
Rate of deafness after meningitis
5%
Acute haematogenous osteomyelitis
Most common age groups & the bacteria seen
Destruction of growth plate in which group
Neonate: GBS, S aureus, E Coli
Femur or humerus
Multifocal in 20-40%
Usually with S.A
Infant: S aureus, strep pneumoniae, Hib, GBS, GAS, K kingae
Single long bone metaphysis
Child: staph aureus, strep, E. coli, K kingae, Salmonella
Sickle cell: salmonella, strep pneumoniae, staph aureus, gram neg
Diaphysis rather than metaphysis affected
Kawasaki differential dx
TSS (staph or strep) Staph scalded skin Scarlet fever Enterovirus Adenovirus Measles Parvovirus EBV CMV Mycoplasma pneumoniae Rickettsiae Leptospira spp
Non-criteria features of Kawasaki
Arthritis Aseptic meningitis Pneumonitis Uveitis Gastroenteritis Meatitis Dysuria Otitis
Proportion of Kawasaki developing aneurysm
Proportion of CAA that regress within 5 y
Mortality rate
20-40%
50% regress within 5 y
3.7%
Infective endocarditis
- native valves: organisms
- prosthetic valves
Strep viridans (mutans, sanguis, mitis)
Staph aureus
Enterococcus ( S faecalis, Strep Bovis)
Staph epi, staph aureus, strep viridans
Brucellosis
Gran stain
Transmission
Incubation
Sx
Dx
Rx
Brucellosis
Gram neg bacilli
Zoonotic, ingestion of unpasteurized milk
Incubation 1-4w
Fever, night sweats, anorexia, wt loss myalgia, lymphadenopathy, HSM
Endocarditis & Osteomyelitis
Blood culture, paired serology
Doxycycline & rifampicin
Lyme disease Where Transmission from Skin sign Clinical features 3w later Late features
US, Europe, UK
Spirochaete borrelia burgdorferi
Transmission from ticks
Bullseye lesion expands to 15cm diameter
Fever, headache, malaise, neck stiffness
3-5w later: CN palsies, meningitis, arthralgia, myalgia, headache
Late: recurrent arthritis, neuropathy & encephalopathy
Listeriosis Gram stain Incubation Source At risk Features of illness
Gram positive bacillus
3-70d
Raw vegetables & meat, soft cheese, meat pate
Fetus, neonate, immunocompromised, pregnant women, elderly
Flu like
Meningoencephalitis, septicaemia
Asymptommatic
Amoxicillin
Leptospirosis Source Incubation Illness Second phase
Treatment
Urine of rats, dogs, livestock
Swimming in contaminated water or direct contact
1-2 weeks
Biphasic:
Fever, rigor, headache,malaise, conjunctivitis
Aseptic meningitis, uveitis, myalgia, lymphadenopathy, vasculitic rash
Penicillin
Or doxycycline
TB
Time from infection to positive mantoux
Defects in what cytokines predispose to infection
Rate closely exposed who develop infection
Rate of infected who develop disease
Risk of disease highest for how many months
2-12w Interferon gamma, IL-12 30% 5-10% Highest risk within 6 months
Gohn focus
Pulmonary macrophages ingest bacteria and mount a cellular immune response
Primary infection controlled over 6-10weeks
Pulmonary foci latercalcify : gohn focus
Neonatal contact with maternal TB
Separate if…
Treatment
Test (when, what)
High risk
Separate if mother is smear positive or has abnormal cxr
Treat for 3 mo with isoniazid then test mantoux and do cxr
Stop if negative
Continue further 3 mo if positive mantoux, negative disease
Triple therapy if disease present
TB chemotherapy
Pulmonary and non-pulmonary (except meningitis)
Isoniazid & rifampicin for 6 mo
First 2 mo with pyrazinamide and eitherethambutol or steptamycin
Same but 12mo total
Atypical mycobacterium
Source
Acquired by
Clinical presentations
Dx
Rx
Soil, food, water, animals
Ingestion, inhalation, inoculation
Disseminated in immunodeficiency and HIV
Lymphadenitis, pulmonary infection, cutaneous infections, osteomyelitis (rare)
Culture or PCR
Mantoux may be weakly positive
Excision of LN
2x drugs for other forms
Parvovirus Incubation Infectious period Presentation Complications
1 week
Until rash appears
Very erythematous cheeks, then erythematous macula papular rash trunk & extremities, fades with central clearing giving a lacy or reticular pattern
Aplastic crisis in chronic haemolytics
Aplastic anaemia
Arthritis, myalgia
Congenital hydrops
HHV-6
Other names for illness
Clinical presentation
Complications
Roseola infantum
Exanthem subitum
High Fever without focus
Day 3-4 fever stops and macular/papular rash appears, lasts 1-3d
Febrile convulsions (often day 1)
TRAPS
Length of fever episode
Associated symptoms
Inheritance
Amyloidosis?
1-3w
Abdominal pain Pleuritis Rash Myalgia Orbital oedema
AD
Amyloidosis in 10-15%
