Infectious diseases 1 Flashcards
What is the transmission route of HSV-1
Respiratory, saliva
What is the transmission route of HSV-2
Sexual contact, perinatal
What is the transmission route of VZV
Respiratory
What is the transmission route of EBV
Saliva - ‘kissing disease’
What is the transmission route of CMV
Congenital, sexual, saliva
What is the transmission route of HHV-6
Saliva
What is the transmission route of HHV-7
Saliva
What is the transmission route of HHV-8
Sexual contact
Presentation of HSV-1 (5)
Gingivostomatitis, keratoconjuctivits, herpes labialis, Temporal lobe encephalitis, eczema herpeticum
Presentation of HSV-2
Genital herpes, Neonatal herpes
Presentation of VZV
Chicken pox, shingles
Presentation of EBV
Mononucleosis (associated with lymphomas, nasopharyngeal carcinoma)
Presentation of CMV (5)
retinitis, hepatitis, colitis, pneumonia, or encephalitis in the immunocompromised
Presentation of HHV6
Roseola Infantum
Presentation of HHV7
Roseola Infantum
Presentation of HHV8
Kaposi sarcoma (Immunocompromised patients)
What is infectious mononucleosis associated with
lymphomas, nasopharyngeal carcinoma
What pathogen causes gingivostomatitis
HSV1
What pathogen causes keratoconjunctivitis
HSV1
What pathogen causes herpes labialis
HSV1
What pathogen causes temporal lobe encephalitis
HSV1
What pathogen causes genital herpes
HSV2
What pathogen causes neonatal herpes
HSV2
What pathogen causes chicken pox
VZV
What pathogen causes shingles
VZV
What pathogen causes infectious mononucleosis
EBV
What pathogen causes roseola infantum
HHV6 and HHV7
What pathogen causes Kaposi’s sarcoma
HHV8
Symptoms of HSV2
Genital herpes (Chronic-life long) flu-like prodrome vesicles/papules around genitals, anus Shallow ulcers Urethral discharge Dysuria Fever and malaise
Mx of HSV1
Topical, oral or IV acyclovir
Peak age on chickenpox
4-10 years
Shingles peak age
over 50
Presentation of varicella 3, describe the rash 2 and where
Prodromal malaise
Mild pyrexia
Generalised pruritic, vesicular rash - face and trunk predominantly
Presentation of varicella zoster and time line
May occur due to stress
Tingling in a dermatomal distribution on one side of the body
Followed by painful skin lesions.
Recovery in 10–14 days.
How long is recovery of varicella zoster
10-14 days
Mx of varicella in children (3)
Treat symptoms
Calamine lotion
Analgesia
Antihistamines
Mx of varicella in adults
Consider aciclovir, valaciclovir or famciclovir if within 24 h of rash onset
Mx of varicella zoster in adults (1st, 2nd line)
1st line: Valaciclovir or famciclovir
2nd line: Aciclovir
if within 72 h of appearance of the rash for 7 days
In who is prevention of varicella zoster indicated (2)
immunosuppressed
Pregnant women exposed to varicella zoster
Presentation of EBV (4)
Fever
Hepatosplenomegaly (jaundice)
Pharyngitis (Tonsillar Exudates)
Lymphadenopathy (Posterior Cervical Nodes)
Triad of infectious mononucleosis
Fever
Lymph adenopathy
Pharyngitis
What is the pathophysiology behind EBV infection
EB infects epithelium of throat and causes pharyngitis
Virions enter lymph vessels and travel to lymph nodes where they attach to B lymphocytes and infect them.
These actively replicate and produce heterophiles antibody.
Activated T cells kill productive B cells.
Latent infected B cells are lifelong.
Ix for mononucleosis (5)
FBC - Lymphocytosis (highest in week 2-3) Blood film - Atypical lymphocytosis Heterophile antibodies - Monospot test EBV specific antibodies Real time PCR - EBV DNA detection
Mx for mononucleosis (3)
Supportive care - Paracetamol or Ibuprofen (anti inflammatory + analgesics)
Corticosteroids may be indicated for severe cases (e.g. haemolytic anaemia, severe tonsillar swelling, obstructive pharyngitis).
Amoxicillin or ampicillin is CONTRAINDICATED due to widespread maculopapular rash
Prognosis of mononucleosis
Recovery in 3-21 days
A 32 year old librarian presents to GP with a history of sharp tingling around his lips followed by a painful ulcer on the side of his mouth. O/E he has cervical lymphadenopathy and a blister on his finger. What is the pathogen and what is on his finger?
HSV1 and herpetic whitlow
A 6-year old girl presents with a fever of 38.5, fatigue and a itchy, maculopapular rash on her face and trunk. Other children at school present with similar symptoms. How should this patient be managed?
Paracetamol with calamine lotion
A wild medical student presents with sore throat and tonsillar exudates, posterior cervical lymphadenopathy and his basic observations are 38.9oC, HR is 90bpm and oxygen saturation on air is 99%. On examination there is splenomegaly. His condition is most likely due to which pathogen?
EBV
A 42-year-old man, previously treated for pneumocystic pneumonia and oral ulcers, presents with a purple, purpural lesion on his nose. Which is the causative organism for this skin lesion?
HSV8
What is pathogenesis of HIV
- HIV enters the CD4 lymphocytes following binding of its envelope glycoprotein (gp120) to CD4 and a chemokine receptor.
- Reverse transcriptase (in viral core) reads RNA to manufacture DNA
- Viral DNA is incorporated into the host genome.
- Dissemination of virions leads to cell death
- Eventually to T-cell depletion.
Ways of HIV transmission
Sex Pregnancy/childbirth/breast feeding Injection drug use Occupational exposure Blood transfusion or organ transplant
4 stages of HIV
Flu-like
Feeling fine
Falling count
Final crisis
What EBV mediated pathology occurs in HIV patients and organ transplant patient
Hairy leukoplakia
What are hairy leukoplakia
Irregular, white, painless plaques on lateral tongue that cannot be scraped off.
EBV mediated.
Occurs in HIV-positive patients, organ transplant recipients.
What does Candida albicans cause
Thrush
What are risk factors to oral candidiasis and oesophageal thrush
Immunocompromisation
What are RF of vulvovaginitis
Diabetes, use of antibiotics
What conditions can candidiasis cause
Oral candidiasis Oesophageal thrush Vulvovaginitis Diaper rash Infective endocarditis Disseminated candidiasis
Which patients are particularly susceptible to disseminated candidiasis
Neutropenic patients
S/s of oral candidiasis and oesophageal thrush
Dysphagia
S/s of Vulvovaginitis/ Balanitis
Thick discharge, itching, soreness, redness
S/s Disseminated candidiasis (3)
Fever, hypotension +/- leucocytosis
Ix for candidiasis (5)
Urinalysis (UTI) Random or fasting blood glucose (Diabetes) Glucose tolerance test (Diabetes) HIV antibody test Vaginal pH test (to exclude STIs)
Systemic candidiasis s/s (3)
fever, hypotension +/- leucocytosis
Where does candidiasis disseminate to (6)
retina, kidney, liver, spleen, bones, CNS
Mx of oral candida (2)
Miconazole oral gelandNystatin suspension
Mx of thrush
Clotrimazole
HIV associated tumours (3)
Kaposi’s sarcoma
Squamous cell carcinoma
Lymphoma
How does Kaposi’s sarcoma present and what causes it
may present as a pink or violaceous (purple) patch on the skin or in the mouth.
HHV8
Ix for HIV (5)
ELISA, confirmed with Western blot
Serum HIV rapid test
Serum HIV DNA PCR - infants
CD4 count – indicates immune status, assists staging process
Serum viral load (HIV RNA) - millions of copies/mL
Centor criteria for tonsillitis (4)
o Tonsillar exudate
o Tender anterior cervical lymphadenopathy or lymphadenitis
o History of fever over 38
o Absence of cough
Ix for tonsillitis
Rapid streptococcal antigen test
Throat culture
Viral causes of tonsillitis (3)
rhinovirus, coronavirus, adenovirus
Bacterial causes of tonsillitis (3)
Group A streptococci
Mycoplasma pneumoniae,
Neisseria gonorrhoea
Which organism usually causes an abscess in the skin
Staph A
What group of patients commonly get perianal (2)
IBD and diabetes
What are ring-enhancing lesions in a HIV patient suggestive of
Toxoplasma Gondii
