Infectious conditions Flashcards
What is an abscess?
Collection of pus built up within tissue over time, associated with Bacteria
What causes an abscess?
Most common sites: Axillae, Anus, Vagina (Bartholin’s abscess), pilonidal and tooth (dental) and groin
Incisional abscesses occur secondary to surgical incision
Caused by obstruction of sebaceous glands or sweat glands, or inflammation of hair follicles, or through minor skin breaks
Caused by bacteria - usually MRSA
What are the Risk Factors for Abscesses?
Immunocompromised i.e. steroid use, AIDS, IV drug use
What are the signs and symptoms for abscesses?
Tender, soft swelling filled with pus
Warm to touch
Surrounded by erythema
May have fever and rigors
What investigations are done for Abscess?
Usually clinical
Can use Ultrasound scan
How do you manage abscesses?
Drain pus from the abscess
- Skin: Cut top of skin and allows pus to drain w/ local anaesthetics, if deep put a small piece of gauze
- In the body: Prescribe Abx
What are the complications of abscesses?
Skin abscesses would normally burst on to skin and let out pus after enlarging and becoming more painful
If in body, very serious
What is Behcet’s disease?
Systemic vasculitis, most commonly seen in Turkey and israel.
Causes skin and mucosal lesions, uveitis, major arterial and venous vessel disease, and GI and Neurological manifestations
What causes Behcet’s disease?
Unknown cause
Associated with HLA-B51
Small vessel ANCA negative vasculitis
What are the Risk factors for Behcet’s disease?
Age 20-40 years
Family history
Genetic predisposition
What are the signs and symptoms of Behcet’s disease?
Tiredness Malaise Muscle pains Transient fevers Headaches Oral ulceration Genital ulceration Eye disease Uveitis Arthritis Vasculitis Myo/pericarditis CNS symptoms Colitis Skin lesions (e.g. Erythema nodosum)
What is the classic triad of Behcet’s disease?
Oral ulceration
Genital ulceration
Eye disease
What are the investigations for Behcet’s disease?
Pathergy testing - SC skin prick performed using a 21-gauge needle & observed formation of a papule / pustule 48 hrs later (positive in 60%)
Rheumatoid factor - Negative
ANA - Negative
Anti-neutralising cytoplasmic ABs - negative
What is Encephalitis?
Inflammation of brain parenchyma associated with neurological dysfunction such as: altered state of consciousness, seizures, personality changes, cranial nerve palsies, speech problems and motor and sensory deficits.
What are the viral causes of encephalitis?
Herpes simplex virus, EBV, VZV Enteroviruses (Enterovirus-71, coxsackievirus, poliovirus) Parechovirus Flavivirus Bunyavirus Togavirus Paramyxovirus Others: Mumps, HIV, Rabies, Measles, Adenovirus, Hep C, Rotavirus, Parvovirus B19
What are the non-viral causes of encephalitis?
Bacterial meningitis TB Malaria Listeria Lyme disease Legionella Leptospirosis Aspergillosis Cryptococcus Schistosomiasis Typhus
What are the signs and symptoms for encephalitis?
Bizarre encephalopathic behaviour Decreased GCS or Coma Fever Headache Focal neurological signs Seizures History of travel / animal bite
What are the investigations for Encephalitis?
Culture
Serum for viral PCR
Toxoplasma IgM tire
Malaria film
Contrast-enhanced CT (B/L temporal lobe involvement suggests HSV encephalitis.)
Lumbar puncture (Raised CSF protein and lymphocytes, and decreased glucose)
EEG (diffuse abnormalities confirm diagnosis)
What is HIV?
Infection with the human immunodeficiency virus
What causes HIV?
Infects and replicates primarily in human CD4+ T cells and macrophages
Reverse transcriptase incorporates HIV genetic material into host genome
Leads to dissemination of HIB, cell death adn eventually T cell depletion
How is HIV transmitted?
Sexual intercourse Bodily fluids (Blood transfusion/organ transplantation) Vertical transmission Breast milk Needles
What are the Risk factors for HIV?
IV drug users Unprotected intercourse Percutaneous needle stick injury High maternal viral load HSV-2 infection
What are the 3 phases of HIV?
Seroconversion (Self-limiting)
Early/asymptomatic
AIDS
What are the signs and symptoms of seroconversion?
Fever Night sweats Generalised lymphadenopathy Sore throat Oral ulcers Rash Myalgia Headache Encephalitis Diarrhoea
What are the signs and symptoms of Early/asymptomatic disease?
Apparently well with progression of symptoms from serconversion
What are the signs and symptoms of AIDS?
Syndrome of secondary diseases due to immunodeficiency?
What are the AIDS defining conditions?
PCP Kaposi's sarcoma Oesophageal candidiasis Salmonella septicaemia Burkitt's lymphoma Immunoblastic lymphoma Primary brain lymphoma
What investigations are done for HIV?
Serum ELISA (positive) Serum HIV rapid test (Positive) HIV non-invasive tests (Positive) Serum western blot Serum HIV DNA PCR Serum p24 antigen Serum viral load Drug resistance Investigations for AIDS defining conditions
What is infectious mononucleosis?
Known as glandular fever
Clinical syndrome most commonly caused by EBV
Other causes a lot less common. Called mononucleosis syndrome when non-EBV pathology
What causes infectious mononucleosis?
EBV aka Human Herpes virus 4 - 80-90% of IM cases
Mononucleosis syndrome may be caused by: Herpes virus 6, CMV, HSV-1 and rarely strep
Pyogenes, toxoplasma gondii, HIV-1, adenovirus
May be caused by a connective tissue disorders, malignancy and drug reactions
What are the symptoms of infectious mononucleosis?
Malaise Fever Rash Yellowing of skin Muscle pains
What are the signs of infectious mononucleosis?
Splenomegaly
Hepatomegaly
Cervical or generalised lymphadenopathy
Pharyngitis