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Exanthematous diseases 2 (Rubella I German measles (Clinical picture (20…
Exanthematous diseases 2
Gas gangrene
-
- Clostridium perfringens and Clostridium septicum:
Gram(+) anaerobic bacillus
spores
- Portal of entry: area of trauma or gastrointestinal tract
(C.novyi, C.septicum, C.histolyticum)
- causes:
Skin infections, infection of subcutaneus tissues, Soft tissue infections
- Low oxygen concentration favours development of gas gangrene:
Tissue ishaemia, Penetrating wounds, Foreign bodies in wounds
Tissue necrosis and coinfections with aerobic bacteria
- Prevention: medical removal of dead/damaged/infected tissues
clinical picture
- Incubation: 1-3 days (usually less than 6 hours)
- Local symptoms:
Sudden severe pain at the site of surgery or trauma
Oedema expandinh within hours
Overlying bullae with clear, red, blue or purple fluid
In surrounding tisues: palpable gas, crepitation
- Signs of systemic toxicity:
fever
shock, tachycardia, multiorgan failure
coma
diagnosis and menagement
- Diagnosis:
Clinical picture
Cultures: tissues and blood (anaerobic medium!)
- Treatment:
Surgical debridement
Antibiotics:
-Penicillin – drug of choice
-Betalactams with betalactamase inhibitors
-Other – imipeneme, clindamicine, tetracycloines
metronidazole
steroids
Hiperbaric oxygen
Rubella I German measles
RNA virus, member of the Togavirus family
humans are the only natural host
acquired via inhalation of infectious large particle aerosols
Prior to the development and introduction of rubella vaccine, outbreaks of rubella occurred variably every few years, peaking in the winter and early spring in temperate areas
The incidence tended to be highest among school-age children
Initial replication: nasopharyngeal cells and regional lymph nodes
Viremia: 5-7 days after inoculation
individuals are potentially contagious for 1-2 before the infection becomes clinically apparent
viral shedding decreases with the appearance of the rash (typically 14 to 17 days after exposure)
IgG antibodies produced after rubella infection provide protective immunity, but reinfection can occur
Clinical picture
20-50% of postnatal rubella are subclinical or asymptomatic
Illness among children tends to be milder than illness among adults
The incubation period of rubella is usually 14 to 18 days (range 12 to 23 days)
- Prodromal symptoms:
1-5 days before the exanthem
Low grade fever
weakness
Lymphadenopathy: posterior cervical, posterior auricular, and suboccipital lymph nodes.
- Rash:
pinpoint, pink maculopapules
first appears on the face, spreads caudally to the trunk and extremities, and becomes generalized within 24 hours
splenomegaly
complications
- Arthritis and arthralgia
- Trombocytopenia: 1/3000 cases
- Encephalitis:
1/5000
mortality 0-50%
in general the prognosis is good
- Kazuistycznie:
Conjunctivitis
Orchitis
Gullain Barre syndrome
diagnosis
- Clinical picture
- laboratory tests:
detection of rubella-specific IgM antibodies
can be detected 4 days after the onset of rash and
usually detectable after primary infection for six to eight weeks or longer
Rubella infection and reinfection can be demonstrated by a fourfold rise in rubella IgG antibody concentrations between acute and convalescent sera
Viral isolation from nasopharyngeal secretions can be used to confirm acute rubella infection during pregnancy
- Differential dignosis:
Other infections: scarlet fever and parvovirus infections, HHV7, HHV8, EBV, enterovirus
skin diseases and drug reactions
-
prophylaxis
- Vaccine:
Live, attenuated
Not effective in postexposure prophylaxis
- Immune globulin:
Used for postexposure prophylaxis
Does not porovide 100% protection
Scarlet fever
upper respiratory tract infection associated with a characteristic rash, which is caused by an infection with pyrogenic exotoxin (erythrogenic toxin) –producing GAS in individuals who do not have antitoxin antibodies
- Pathogenesis:
Streptococcal pharyngitis or tonsillitis, celullitis
GAS produce erythrogenic toxin
- Source of infection – human with streptococcal pharyngitis, convalescent, carrier
- Transmission route:
droplets
Person to person
Indirect contact (objects) rare
- contagiousness
- On antimicrobial treatment infctivity ceases after 24 hours
- Incubation period: 1-4 days
- Prodrome:
Sudden onset
Fever, chills, weakness
Nausea, vomiting, diarrhoea
Signs of pharyngitis
Cervical lymphadenopathy
Headache, myalgia
Rash
- Appears after 12-48 hours
- begins around the neck and spreads over the trunk and extremities
- diffuse, finely papular, erythematous eruption producing bright red discoloration of the skin, which blanches on pressure
- diffuse, finely papular, erythematous eruption producing bright red discoloration of the skin, which blanches on pressure
- Filatov’s triangle: The cheeks are often erythematous with pallor around the mouth
- Red tongue: initially white strawberry tongue, after 2 days: red strawberry tongue
- After 3-4 days, the rash begins to fade and is followed by desquamation, initially on the face, progressing downward, and often resembling a mild sunburn
Smallpox
-
- Source of infection: ill man and the body of the deceased due to smallpox
- Infectivity: from the appearance of the skin lesions until last crust fall off (approx. 3 weeks).
- Transmission route:
droplets
air (respiratory secretions, parts of scabs);
indirect contact
Small inlouries of the skin
Contact with mucosa of the alimentary tract (ingestion of crusts)
rash
Evolution of skin changes as in chickenpox but…
Pustules are more porminent, firm, deeper embedden in the skin
Rash is monomorphic
(all skin changes evolve simultanously)
Distal distribution
Palms and soles involvment >50%
Leaves scars