Infection 1 Flashcards
HHV types?
1 and 2 are HSV1/2. 3 = VSV 4 = EBV 5 = CMV 6/7 are 6/7 8 = 8
What can HSV-1 Cause?
Gingiovstomatitis, keratoconjunctivitis, herpes labialis, temporal lobe encephalitis.
ECZEMA Herpticum and herpteic whitlow
HSV-2 Presentation?
Gential herpes (lifelong) -> flu like prodrome -> vesicles papules around gentials and anus Shallow ulcers Urethral discharge Dysuria Fever and Malaise
How does acyclovir work?
Guanosine analogue that inhibits viral DNA polymerase as anaologue of dGTP. Absence or 3’hydroxyl group prevents nucleoside attachment
HSV investigations and treatment?
Clinical diagnosis but mayb viral culture or HSV PCR
Topical, oral or IV acyclovir
Varicella Zoster incidence?
Is in dorsal root ganglia.
Chickenpox = 4-10
Shingles =>50 YO
90% adults VSV IgG +ve
Presentation of chickenpox?
Prodromal malaise Mild pyrexia Generalised pruritic vesicular rash Maculopapular Contagious from 48hours until all vesicles crusted (7-10 days)
Shingles presentation?
May occur due to stress and tingling in dermatomal distribution followed by painful vesicular skin lesions. recovery 10-14 days
Investigations and Pox managment?
Clinical diagnosis, maybe PCR, viral culture or ELISA.
Chldren = treat symptoms with calamine otion, analgesia and antihisamines
Treatment and prevention of shingles?
1st line = valaciclovir or famciclovir
2ns line = acyclovir if within 72hours of appearance of rash.
VZIG for immunosuppressed and pregnant women exposed
Complications of VSV?
kids: bacterual sepsis, pneumonia, encephalitis and haemorrhagic complication
Adults: POSTHERPETIC NEURALGIA
Also: menigoencephalitis, myeltis, cranial nerve palsy, vasculopathy, GI ulcers, pancreatitis and hepatitis
EBV names and aetiology?
infectious mononucleosis and glandular fever.
90-95% of eople at some point and spread by saliva droplets.
Infects B lymphocytes and incorporation of viral DNA into host DNA
EBV presentation?
Fever, hepatosplenomegaly (jaundice), pharyngitis (tonsillar exudates) and lymphadenopathy (posterior cervical)
ATYPICAL LYMPHOCYTOSIS
EBV Investigations?
1) FBC (lymphocytosis) highest in week 2-3
2) Blood film - ^
3) Heterophile Abs
4) EBV Specific Abs
5) Rea time PCR for EBV DNA detection
EBV management?
Supportive care (antiinflammatory and analgesics) Corticosteroids if severe
AMOXICILLIN or ampicllin is contraindicated fue to widespread maculopapular rash
throat swab to exclude Group A strep
Components of EBV specific Abs?
IgM, IgG and EBNA. None = no infection IgM = early infection IgG+IgM = acute primary infection IgG+EBNA = past infection
Difference in presentation fro EBV and Strep pyogenes?
Strep has anterior cervical lymphadenopathy and no splenomgealy
Causative organism for purple, purpural lesion on nose?
HHV-8 (Kaposis)
HIV features?
Pneumocystic pneumonia
How does HIV work?
Retrovirus (+sense RNA)
1) Enters CD4 lmphocytes via gp120 and chemokine receptor
2) Reverse transcriptase RNA to DNA
3) Viral DNA incoporated
4) Dissemination of virions leads to cell death
5) Eventually to T-cell depletion
Methods of HIV transmission?
Sexual contact, pregnancy, childbrith and breastfeeding, occupational exposure, blood transfusion or organ transplant and injection drug use
Stages of untreated HIV?
4F’s
1) Flu-like
2) Feeling Fine
3) Falling count and FInal crisis in AIDS
Capsulated organisms in HIV presentation?
Strep pneumoniae
Haemophilus influenzae
Bacterial presentation for HIV?
Mycobacteria (lungs GI skin), staphylococci, salmonella, capsulated organisms
Viral presentation of HIV?
CMV, HSV (encephalitis), VSV (recurrent shingles), HPV (warts), papovavirus (progressive multifcal leukoencephalopatgy), EBV (oral hairy leukoplakia)
Protozoal presentation of HIV?
Toxoplasmosis, crytosporidia and microsporidia (diarrhoea)
Common HIV XRAY?
Severe, bilateral pukmonary interstitial infiltrates with pneumotoceles
= Pneumocystic pneumonia
What is jairy leukoplakia?
Irregular, white, painles tongue plaques that cannot be scraped iff.
EBV mediated in HIV positive patients
Candidiasis conditions and RFs?
Oral candidiasis and oesophageal thrush = immunocompromised
Vulvovaginitis = diabetes and Abx use
Duiaper rash
Infective endocarditis (IV drug users)
Disseminate candidiasis (in neutropenic patients
Signs/symptoms pof candidiasis?
Oral = dysphagia Vulvo/balanitis = thick discharge, itching, soreness, redness
Disseminated = fever, hypotension +/- leucocytosis
Investigations for candidiasis?
Swabs not routinely done.
To exclude others:
Urinalysis (uti), Blood glucose (diabetes), HIV Ab test and vaginal pH test (UTI)
What are the HIV associated tumours?
Kaposi sarcome (HHV8). Pink or violaceous (purple) patch on skin or mouth. In AIDS defining condition.
Squamous cell carcinoma = particularly cervical or anal from HPV
Lymphoma
Treatment = chemotherapy + radiotherapy or anorectalexcision and colostomy
What are the 1st line HIV investigations?
1) ELISA (western blot)
2) Serum HIV rapid test
3) Serum HIV DNA PCR (Infants)
4) CD4 count
5) Serum viral load (RNA)
What are other HIV investigations?
Drug resistance therapy, serum Hep B and C, treponema pallidum haemagglutination test (syphilis)
Tuberculin skin test (TB)
FBC, U&Es, LFTs
What is and aetiology of tonsillitis?
Acute infection of parenchyma of palatine tonsils. May occur in isolation or part of generalized pharyngitis
Viral (Common): Rhinovirus, coronavirus, adenovirus, EBV
Bacterial: Group A strep, mycoplasma pneumoniae, neisseria gonorrhoea
Investigations for tonsillitis?
Rapid streptococcal antigen test
Throat culture
Signs and symptoms of tonsillitis?
Pain on swallowing, temp >38, tonsillar exudate, sudden onset sore throat, tonsillar erytherma and enlargement, anterior cervical lymphadenopathy
What are the centor criteria?
\Tonsillar exudate, tneder anterior cervical lymphadenopathy or lympohadentism hisotyr of fever >38
Absence of cough.
2 or less = no further investigations
3 or more = rapid streptococcAL ANTIGEN TEST
Common Cold definition and investigations?
Mild, self-limiting, upper respiratory tract infection characterized by nasal stuffiness adn discharge, sneezing, sore throat and cough
Clinical diagnosis: consider FBC, throat swab, sputum culture, CRP, CXR
Common cold signs and symptoms?
Runny or blocked nose, sneezing, sore throat, cough, headache, malaise and fever.
Usually clear in 7-10 days
Management of common cold
hydration, analgesic, antipyretic, decongestant (oxymetazozline nasal, ipratropium nasal) +/- antihistamine, antitussive
Common respiratory tract bacteria?
Strep pneumoniae, haemophilus influenzae, moraxella catrrhalis
Abscess definition and aetiology?
Collection of pus that builds up in tissue, organ or confined space walled off by fibrosis.
Usually bacterial infection but rarely parasite or foreign sbstance
Most common skin abscess cause and signs?
Staph aureus. Erytherma, hot, oedema, pain and loss of function
Investigations fr abscess?
Hx, examinations, obvs, CLINICAl diagnosis and USS
Management for absces?
Uncomplicated: aspiration, incision and drainage and no need for Abx
Severe or multiple sites: Abc, incision and drainage, excision if serious
Features of toxoplasma gondii?
Associated with cats. Can cause myocarditis, encephalitis, Focal CNS signs, stroke and seizures.
CT - characteristic multiple ring-shaped enhancing lesions
