Infection Flashcards
What is Cellulitis?
Inflammation of the skin and subcutaneous tissues, typically due to infection by Streptococcus pyogenes or Staphylcoccus aureus
What are the main presenting features of cellulitis?
Shins Erythema Pain Swelling Systemic e.g. fever
How is cellulitis diagnosed?
Clinically
Bloods + culture might be requested if septicaemia is suspected
When would you consider admitting a patients with cellulitis?
Significant systemic upset Unstable co-morbidities Limb threatening infection (vascular compromise) Sepsis Necrotising fasciitis
What is the first line treatment for mild/moderate cellulitis?
Flucloxacillin
Clarithromycin if allergic
What is the first line treatment for severe cellulitis?
Co-amoxiclav
Cefuroxime
Clindamycin
What are some RFs for cellulitis?
Breaks in skin e.g.
Eczema
Leg ulcers
What do you look for in someone presenting fever unrelated to travel?
CAP, UTI, Cellulitis VIral Infective endocarditis Osteomyelitis Abscess
What are causes of fever in the returning traveller?
Viral (Dengue)
Bacterial (Salmonella, typhi/paratyhi)
Parasites (Malaria)
Respiratory (COVID, Flu,)
GI/GU (Schistosomiasis)
What should you consider when trying to diagnose fever in a returning traveller?
Location of travel
Incubation period
Exposures e.g. bites/sexual contact/contaminate food water
What are differentials for a non-infective fever?
Immunological inflammatory e.g. SLE, Vasculitis
Malignancy
Endocrinology e.g. thyrotoxicosis, adrenal insufficiency
Metabolic e.g. gout
Tissue destruction e.g. rhabdomyolysis
Misc e.g. drug induced, incompatible transfusion
What blood smears can be used to identify plasmodium falciparum?
Giesma stain thick/thing smears
Also can use rapid diagnostic tests
What is the management of malaria?
Admission and infectious disease specialist
What would be the aims of treatment of infections?
- eradicate infection
- reduce risk of complications
- avoid selecting resistance by using multiple agents
What is complicated malaria?
Organ failure
Needs admission for IV fluid treatment
What is the management for complicated falciparum malaria?
IV artesunate
Strict fluid balance
Involve ITU early
What is the management for non-complicated falciparum malaria?
Artemether with lumefantrine for 3 days
OR
Artenimol with piperquine phosopate
What is the management for non-complicated non-falciparum malaria?
Artemether with lumefantrine for 3 days
14 day course of primaquine to prevent relapse
What should you consider before prescribing quinines?
Think about G6PD deficiency
Common in west africa
How is malaria monitored?
Daily blood films until parasites are undertaken until parasite no longer detected
What are features of severe malaria?
schizonts on a blood film parasitaemia > 2% hypoglycaemia acidosis temperature > 39 °C severe anaemia
What are potential complications of malaria?
cerebral malaria: seizures, coma
acute renal failure
acute respiratory distress syndrome (ARDS)
hypoglycaemia
disseminated intravascular coagulation (DIC)
What are the symptoms of acute conjunctivitis?
Irritated red eye
Watery or purulent discharge
Mucoid discharge
Swollen eyelids
What causes conjuctivitis?
Allergy Bacterial/Viral infection Mechanical stress Irritation by toxic chemicals or medication Exposure to infected person
What is the diagnostic test for conjuctivitis?
Rapid adenovirus immunoassay
Tear fluid sample
What is the management for allergic conjunctivitis?
first-line: topical or systemic antihistamines
second-line: topical mast-cell stabilisers, e.g. Sodium cromoglicate and nedocromil
What is the management for infective conjunctivitis?
Usually self-limiting
Topical ABs e.g. chloramphenicol drops or fusidic acid
Do not wear contact lenses
Define COVID-19
potentially severe acute respiratory infection caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
What are the presenting features of COVID infection?
Respiratory infection: Fever Cough Dyspnoea Loss of taste/smell
Complications:
Multi-organ failure
Septic shock
Venous thromboembolism
What investigations are done for COVID?
real-time reverse transcription PCR
What is the management for mild covid?
Home isolation
Monitoring
Supportive care
Anti-pyretic/analgesia
What is the management for severe covid?
Admission O2 therapy VTE prophylaxis ABs Anti-viral
What is the management for critical covid?
ITU High flow nasal O2 or NIV Manage sepsis Corticosteroid IL-6 inhibitors JAK inhibitor Palliative?
What is the classic clinical presentation of herpes simplex virus infection?
Vesicles progressing to painful ulcers
But is unusual
What are symptoms of oral herpes?
Tingling/burning
Vesicular to ulcerative lesions
Oropharynx and perioral mucosa
HSV-1
What causes genital herpes?
HSV-1
HSV-2
What are RFs for HSV infection?
HIV
Immunosuppressive medications
High-risk sexual behaviour
What investigations are ordered in HSV infection?
HSV PCR Viral culture (swab ulcer/vessicles)
What is the treatment for cold sores in HSV infection?
Topical aciclovir
What is the treatment for genital herpes?
Oral aciclovir
What is advised to pregnant women with herpes infection?
Elective C-section at term if HSV infection is after 28 weeks
Women with recurrent herpes should be treated with suppressive therapy
Define HIV
retrovirus that infects and replicates in human lymphocytes and macrophages, eroding the integrity of the human immune system
What are RFs for HIV?
Blood transfusion
IV drug use
Unprotected sex
Needle prick injury
What are some presenting features of HIV?
FLAWS Rashes Ulcers Diarrhoea Mental state changes TB STIs Shingles
What investigations confirm HIV infection?
HIV ELISA
Serum HIV rapid test
Serum Western blot
What is the management for newly confirmed HIV?
Anti-retroviral therapy
3x drugs usually:
2x Nucleoside reverse transcriptase inhbitor
1x Protease inhibitor
Reduces risk of viral resistance and replication
What is PEP?
Post-exposure prophylaxis is the administration of antiretroviral therapy to HIV-negative people who may have been occupationally or sexually exposed to HIV
Give an example of a nucleoside reverse transcriptase inhibitor
Zidovudine
Give an example of a protease inhibitor
Darunivir
Give an example of a non-nucleoside reverse transcriptase inhibitor
Nevirapine
What are some lower respiratory tract infections?
Bronchitis
Bronchiolitis
Chest infection
Pneumonia
What are some upper respiratory tract infections?
Common cold
Sinusitis
Tonsilitis
Laryngitis
Define bronchiolitis
Viral bronchiolitis is an acute viral infection of the lower respiratory tract
Most common in infants caused by RSV
Define tonsilitis
nflammation of the tonsils; specifically it is an infection of the parenchyma of the palatine tonsils
What are the presenting features of tonsolitis?
Pain on swelling
Fever > 38
Tonsillar exudate
What investigations are done for tonsillitis?
Throat culuture
Rapid streptococcal antigen test
What is the management for tonsillitis not due to strep infection?
Analgesia
What is the management for tonsillitis due to strep infection?
Analgesia
ABs
Corticosteroids
What is the management for recurrent tonsillitis?
Tonsillectomy if 5 or more episodes a year
At least a year
Symptoms are disabling
What should a doctor do if a notifiable disease is suspected in your healthcare setting?
Statutory duty to notify the local health protection team
Complete notification form on govt website
List of disease found here too
What is varicella-zoster?
Chicken pox
Human alpha herpes virus
What are the presenting features of varicella-zoster infection?
Fever Malaise Generalised pruritic rash Vesicular rash Usually self-limiting
How is varicella-zoster diagnosed?
Clinically
Can do PCR/Viral culture
What is the treatment for children with increased risk?
Oral antivrial
Aciclovir
Increased risks include atopic dermiatitis, pulmonary disease or on corticosteroids
How can chickenpox be caught?
spread via the respiratory route
can be caught from someone with shingles
What is supportive management for chickenpox?
Keep cool
Trim nails
Calamine lotion
School exclusion
What is shingles?
acute, unilateral, painful blistering rash caused by reactivation of the varicella-zoster virus
dermatomal as virus lies dormant in dorsal root ganglion or cranial nerve ganglia
Who is eligible for a primary (chickenpox) varicella infection?
Healthcare workers not already immune
Contacts of immunocompromised pts
Who is offered a shingles vaccine?
70-79 year olds
What are the features of shingles?
Prodromal period: Burning pain over affected dermatome Fever Headache Lethargy Rash
What are the features of rash in shingles?
Erythematous, macular initially
Becomes vesicular
Dermatomal
What is the management of shingles?
Remind they are potentially infectious need to avoid pregnancy and immunocompromised
Analgesia - paracetamol and NSAIDS
Antivirals - aciclovir
What can a maculopapular rash also be known as?
Exanthem
Morbilliform eruption
What can cause viral exanthema?
Enterovirus Echovirus EBV Rubella Acute Hep B/C infection Ebola Zika Dengue
What is viral exanthem?
non-specific viral rash caused by a viral infection
How does viral exanthem present?
Widespread rash Pink-red spots or bumps Primarily trunk, arms and legs May or may not be itchy Might have systemic symptoms
Define viral gastroenteritis
acute inflammation of the lining of the stomach and intestines caused by enteropathogenic viruses
What is the typical presentation of viral gastroenteritis?
Increased defacation frequency <14 days Nausea Vomiting Anorexia Abdominal cramps Fever
What are some RFs for viral gastroenteritis?
Exposure to contaminated food or water sources
Close contact with infected people
Poor hygeine
HIV
What viruses are most commonly associated with gastroenteritis?
Norovirus
Sapovirus
Rotavirus
How can you diagnose viral gastroenteritis?
Clinical history
Stool viral PCR
What is the management for viral gastroenteritis?
Self-limiting so supportive
Hydration
Correct electrolyte imbalances
Define peri-orbital cellulitis
Inflammation and infection of the superficial eyelid
Confined to soft-tissue layers
Occular function remains intact
Define orbital cellulitis
Infection within the orbital soft tissues with associated ocular dysfunction and is usually due to underlying bacterial sinusitis
Serious and warrants hospital admission
What are some presenting features of peri/orbital cellulitis?
Redness and swelling of the eye Ocular pain Decreased vision Eyelid oedema Exopthalmos
What are some RFs for peri/orbital cellulitis?
Sinusitis
Young age
Male sex
Lack of Hib vaccine
How do you diagnose peri/orbital cellulitis?
Clinical examination
CT sinus and orbits with contrast
WCC
What is the management for orbital cellulitis?
Hospitalisation for IV ABs
What are night sweats?
Profuse sweating at night soaking the bed despite cool environement
What causes night sweats?
Menopause Anxiety Medications Hypoglycaemia Alcohol/Drug use Malignancy
