Infections Flashcards
Infections
What is glandular fever also known as?
Infective mononucleosis
What is the most common cause of infective mononucleosis?
EBV
What proportion of people have had infective mononucleosis?
90-95% of world population
What is the classic triad of infective mononucleosis?
Lymphadenopathy
Pharyngitis
Fever
How is infective mononucleosis transmitted?
EBV most commonly spread by saliva/ respiratory droplets. other bodily fluids: Sexual transmission Blood products organ transplant
How may infective mononucleosis present?
Fever 1-2 weeks Hepatosplenomegaly (jaundice) Pharyngitis (Tonsillar Exudates) Lymphadenopathy (Posterior Cervical Nodes) Photophobia, cough, fatigue, headache
What are the investigations for infective mononucleosis? What would you see?
FBC - Lymphocytosis (highest in week 2-3)
Blood film - Atypical lymphocytosis
Heterophile antibodies- Monospot test
EBV specific antibodies (high sensitivity)
Real time PCR - EBV DNA detection
Throat swab to exclude Group A Strep (Streptococcus pyogenes)
What are the three EBV specific antibodies measured?
EBV Viral capsid antigen (VCA) IgM
EBV VCA IgG
Epstein-Barr nuclear antigen (EBNA) appears 6-12 weeks after onset of symptoms
What EBV specific receptors will be seen in a healthy Pt without EBV?
- ve VCA IgM
- ve VCA IgG
- ve EBNA IgG
What EBV specific receptors will be seen a Pt with early infective mononucleosis?
+ve VCA IgM
- ve VCA IgG
- ve EBNA IgG
What EBV specific receptors will be seen a Pt with acute infective mononucleosis?
+ve VCA IgM
+ve VCA IgG
-ve EBNA IgG
What EBV specific receptors will be seen a Pt with a history of infective mononucleosis?
-ve VCA IgM
+ve VCA IgG
+ve EBNA IgG
What is the management for a Pt with infective mononucleosis?
Supportive care - Paracetamol or Ibuprofen (anti inflammatory + analgesics)
Corticosteroids may be indicated for severe cases (e.g. haemolytic anaemia, severe tonsillar swelling, obstructive pharyngitis).
Why should you not give aspirin to children?
Risk of developing Reye’s syndrome
Causes swelling in the liver and brain
What are the two conditions caused by varicella zoster infections?
Chicken pox (aka varicella) Shingles (aka herpes zoster)
What are the characteristics of varicella?
Fever
Malaise
Generalised pruritic vesicular rash
What are the characteristics of herpes zoster?
Reactivation of VZV
Dermatomal distribution of rash
What are the risk factors for a VZV infection?
> 50 yrs or child
HIV +ve
Chronic corticosteroid use
aka any form of immunosuppression
What are the investigations for a VZV infection?
Clincial diagnosis
Can consider PCR, viral culture, ELISA
What is the management for varicella?
Supportive care
Paracetamol
Diphenhydramine (antihistamine)
Avoid aspirin and NSAIDs
What is the management for HSV ?
Antiviral therapy:
1st line- famciclovir/valaciclovir
2nd line- acyclovir
What are the complications of VZV? (MOPS)
Meningoencephalitis
Ocular complications
Peripheral nerve palsy
Spinal cord myelitis
What can a HSV1 infection cause?
Herpes labialis (cold sores)
Genital herpes
HSV encephalitis
What can a HSV2 infection cause?
Genital herpes
How may a HSV1 infection present?
Gingivostomatitis, cold sores – ulcers filled with yellow slough near the mouth
Herpetic whitlow – vesicle in finger
Eczema herpeticum – HSV infection on eczematous skin
Herpes simplex meningitis – rare, self-limiting
Systemic infection – fever, sore throat, lymphadenopathy, pneumonitis, and hepatitis
Herpes simplex encephalitis - fever, fits, headaches, odd behaviour, dysphasia, hemiparesis
keratoconjunctivitis: Epiphoria (watering eyes), photophobia
How may a HSV2 infection present in a male?
Vesicles on shaft or glands Proctitis with discharge Rectal pain Tenesmus Constipation Impotence
How may a HSV2 infection present in a female?
Genital herpes (Chronic-life long) flu-like prodrome vesicles/papules around genitals, anus Shallow ulcers Urethral discharge Dysuria Fever and malaise
What are the investigations for HSV infections?
Usually clinical diagnosis
Viral culture
HSV PCR
What type of virus is HIV caused by and what cells does it infect?
Retrovirus
Human lymphocytes/macrophages
What are the routes of HIV transmission?
Sexual contact Before birth During delivery Breast feeding IVDU Blood transfusion (rare)
What are the 3 stages of HIV infection?
- Primary- seroconversion (4-8 weeks)
- Asymptomatic (18 months –> 15yrs)
- AIDS-related complex (
Think 4 Fs- Flu –> Fine –> falling CD4 –> final crisis
What is the primary HIV stage?
Seroconversion:
4-8 weeks post infection
self-limiting – fever, night sweats, generalized lymphadenopathy, sore throat, oral ulcers, rash, myalgia, headache, encephalitis, diarrhoea
What is the asymptomatic HIV stage?
Apparently well
some patients may have persistent lymphadenopathy (>1 cm nodes, at 2 extrainguinal sites for >3 months).
Progressive minor symptoms, e.g. rash, oral thrush, weight loss, malaise.
CD4 <400x10^6
What is the AIDS-related complex HIV stage?
Syndrome of secondary diseases reflecting severe immunodeficiency
…or direct effect of HIV infection
CD4 <200x10^6
What is the cause of oral candidiasis?
Fungal candida infection
Due to immunosuppression
What is the cause of hairy leukoplakia?
Triggered by EBV
Occurs in HIV-positive patients, organ transplant recipients.
What is the cause of Kaposi’s sarcoma?
HHV-8
AIDS-defining condition (opportunistic infections and cancers that are life-threatening in a person with HIV.)
What are the investigations for HIV?
ELISA Serum HIV rapid test Sample buccal saliva HIV PCR CD4 count
What are some common pathogens that cause tonsillitis?
Rhinovirus Coronavirus Adenovirus Beta-haemolytic Strep (pyogenes) Mycoplasma pneumoniae Neisseria gonorrhoea
What are the features of tonsillitis?
Pain on swallowing Fever Tonsillar exudate Sudden onset sore throat Tonsillar erythema Tonsillar enlargement Anterior cervical lymphadenopathy
What are the investigations for tonsillitis?
Throat culture
Rapid streptococcal antigen test
What are the common locations of candidiasis?
Mouth
Genitals
What is systemic candidiasis?
Acute disseminated candidiasis to blood, pleura and peritoneal fluid
Associated with fever, hypotension and leukocytosis
What are the risk factors for candidiasis?
HIV Malnutrition Diabetes Malignancy Chemotherapy/radiotherapy Other forms of immunosuppression
What are the investigations for candidiasis?
Superficial smear for microscopy
Urinalysis
Random/fasting glucose
What are the pathogens that cause the common cold?
Rhinoviruses (50%) Coronavirus (10-15%) Influenza (5-15%) Parainfluenza (5%) Respiratory syncytial virus (5%)
Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
What is an abscess?
Collection of pus that has built up within a tissue, organ or confined space walled off by fibrosis.
What are the features of an abscess?
Erythema Hot Oedema Pain Loss of function Fever Systemically unwell
What is the investigation for an abscess?
Clinical diagnosis
What is the management for an abscess?
Incision and drainage
Only give antibiotics if severe eg:
Sepsis, cellulitis, multiple sites of infection
What is Bartholin’s abscess?
A build up of pus in one of Bartholin’s glands, found on each side of the vaginal opening
What is Quinsy’s abscess?
A build up of pus between one of the tonsils and the wall of the throat
What is a pilonidal abscess?
A build up of pus in the skin of the cleft of the buttock
What are the common causes of meningitis?
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenza type B
What is a common cause of encephalitis?
HSV-1
What are the features of meningitis?
Stiff neck
Photophobia
Non-blanching rash
What are the features of encephalitis?
Altered state of consciousness Seizures Personality change Cranial nerve palsies Speech problems Motor and sensory deficit
What are the investigations of meningitis?
LP if there are no clinical features of raised ICP
What is the management for meningitis?
SECONDARY CARE
- Empirical IV Abx within 1 hour of presentation (immediately after blood cultures + LP)
- ceftriaxone/cefotaxime +/- vancomycin
(if >60/immunocompromised also add amoxicillin)
PRIMARY CARE
- Urgent hospital transfer
- IM/IV benzylpenicillin
or - ceftriaxone/cefotaxime
What is Brudzinski’s sign?
Neck flexion causes hip and knee to flex
What is Kernig’s sign?
Cannot straighten leg when hip is at 90 degrees
What does the following CSF sample show?
Appearance- clear WCC- low Protein- normal Glucose- normal Gram stain- NA
Normal CSF
What does the following CSF sample show?
Appearance- turbid WCC- high neutrophil Protein- high Glucose- low Gram stain- positive
Gram positive bacterial meningitis
eg. Streptococcus pneumoniae
What does the following CSF sample show?
Appearance- turbid WCC- high neutrophil Protein- high Glucose- low Gram stain- negative
Gram negative bacterial meningitis
eg. Neisseria meningitidis
What does the following CSF sample show?
Appearance- clear/cloudy WCC- high lymphocyte Protein- raised Glucose- normal Gram stain- NA
Viral meningitis
What does the following CSF sample show?
Appearance- clear/cloudy WCC- high lymphocytes Protein- raised Glucose- low Gram stain- NA
TB/Fungal meningitis
What further investigation could be done to differentiate between a TB and fungal meningitis?
Ziehl-Neeslon stain- TB
India ink stain- fungal
What are the risk factors for infective endocarditis?
Rheumatic heart disease Hx Age-related valvular degeneration Prosthetic valve (S. epidermidis) IVDU (Staph. aureus) Dental procedures (S. viridans)
What are the investigations and management for infective endocarditis?
3 blood cultures at least 1hr apart within 24hrs
Urgent echo
Broad spec antibiotics
Which infections can cause gastroenteritis with diarrhoea?
Campylobacter/C difficile
Bacillus cereus
E. coli
Vibrio cholera
Staph aureus
Which infections can cause gastroenteritis with dysentery?
CHESS
Campylobacter/C difficile Haemorrhagic E. coli Entamoeba histolytica Shigella Salmonella
What are the investigations for gasteroenteritis?
FBC
Stool MC+S
How is Hep A and E transmitted?
Faecal-oral route
What is the management for Hep A and E?
Supportive care
What are the clinical features of Hep B?
Flu-like prodrome Rash Lymphadenopathy RUQ pain Jaundice
What are the risk factors for Hep B?
Unprotected sex
MSM
IVDU
Blood transfusion
What is the management for Hep B?
Acute- supportive
Chronic- peginterferon alpha, Tenofovir
Can you get Hep D without Hep B?
No
What is the main worry for Hep B/C?
Risk of HCC
What are the common pathogens of UTIs?
Proteus mirabilis (complicated UTI)
Escherichia coli
Enterococcus faecalis
Staphylococcus saprophyticus (young, sexually active)
Klebsiella pneumoniae
What are the investigations for a UTI?
Dipstick urinalysis- positive nitrates +/- leukocytes
Urine microscopy- leukocytes
Urine MC&S
Abdo USS- exclude urinary tract obstruction or renal stones
What is the management for a UTI?
Trimethoprim
What are the five types of malaria?
Plasmodium falciparum Plasmodium vivax Plasmodium ovale Plasmodium malariae Plasmodium knowlesi
What are the characteristics of Plasmodium flaciparum?
Most threatening Common in tropical regions: Sub-Saharan Africa South east Asia Oceania Amazon basis of South America
What are the features of malaria?
Headache Weakness Myalgia Arthralgia Anorexia Diarrhoea Fever - Characteristic paroxysms of chills and rigors followed by fever and sweats may be described
What are the investigations for malaria?
Giemsa-stained thick and thin stains
Thick- detects parasites
Thin- identifies species
FBC, Clotting profile, U+E, LFTs, blood glucose, Urinalysis, ABG
A 30 yo lady on the HIV ward has white plaques all over her tongue that extend into her throat. She says it’s very painful to swallow.
What is the most likely causative organism?
A. Candida albicans B. Epstein-Barr virus C. Herpes Simplex Virus D. Streptococcal throat infection E. Human Herpes Virus 8
A. Candida albicans
A 50 year old homeless man presents to A&E with purple purpural lesions on his back and on his gums.
What is the most likely causative organism?
A. HHV-2 B. HHV-4 C. HHV-5 D. HHV-7 E. HHV-8
E. HHV-8
A 26 year old architect 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?
A. Varicella Zoster Virus B. Epstein-Barr Virus C. Herpes Simplex Virus 1 D. Herpes Simplex Virus 2 E. Cytomegalovirus
C. Herpes Simplex Virus 1
A 20 year old medical student presents with sore throat, headache, myalgia and coryzal symptoms. O/E she has cervical lymphadenopathy, enlarged exudative tonsils and splenomegaly.
What is the most likely diagnosis?
A. Varicella Zoster Virus B. Epstein-Barr Virus C. Herpes Simplex Virus 1 D. Herpes Simplex Virus 2 E. Cytomegalovirus
B. Epstein-Barr Virus
A 20 year old medical student presents with sore throat, headache, myalgia and coryzal symptoms. O/E he has cervical lymphadenopathy, enlarged exudative tonsils and splenomegaly.
What is the most appropriate management?
A. Rest at home, paracetamol B. Amoxicillin C. Acyclovir D. Ceftriaxone E. Vancomycin
A. Rest at home, paracetamol
A 15 year old female patient presents to A&E with difficulty speaking. 4 days ago she experienced a sore throat, which progressively got worse. It’s now difficult for her to speak or swallow. She has not had a cough or cold recently.
O/E there is bilateral tonsillar exudate and the oropharynx is not erythematous. There are 3 tender swellings on the anterior border of the sternocleidomastoid muscle.
Her observations are: T 39.1, HR 90, BP 113/68, SpO2 97%
What is the most likely diagnosis?
A. Infectious mononucleosis B. Viral tonsillitis C. Common cold D. Bacterial tonsillitis E. Chickenpox
D. Bacterial tonsillitis
A 22 year old university student is seen in the GP with a fever, headache, neck stiffness and photophobia. Which is the most likely causative organism in this patient?
A. Bacterial meningitis due to Haemophilus influenzae
B. Bacterial meningitis due to Neisseria meningitides
C. Bacterial meningitis due to Streptococcus pneumoniae
D. Fungal meningitis
B. Bacterial meningitis due to Neisseria meningitides
A 22 year old university student is seen in the A&E with a fever, headache, neck stiffness and photophobia. A lumbar puncture was performed. The appearance of the fluid is clear, there are raised proteins and normal glucose. Lymphocyte count is raised. What is the most likely cause of this?
A. Bacterial meningitis B. Drug induced meningitis C. Fungal meningitis D. TB meningitis E. Viral meningitis
E. Viral meningitis
40 year old woman returns from holiday in Vietnam. She started getting diarrhoea after eating some local food on her last day in Vietnam. She presents with fever, nausea and is sore all over. The white of her eyes are yellow.
What is the most likely causative organism?
A. Hepatitis A B. Hepatitis B C. Hepatitis C D. Hepatitis D E. Hepatitis E
A. Hepatitis A
A 29 yo male comes to the GP with fever, fatigue, joint pain and urticaria-like skin rash. He had unprotected anal sex a month ago. He comes back a week later for a blood test, which shows raised ALT and AST. He now complains of feeling sick, RUQ pain and looks a bit yellow.
What is the most likely causative organism?
A. Hepatitis A B. Hepatitis B C. Hepatitis C D. Hepatitis D E. Hepatitis E
B. Hepatitis B
A 70 yo M has been in hospital for the past two weeks for severe pneumonia. He develops bloody diarrhoea, colitis and reduced urine output. He has raised CRP, WCC and low albumin.
What is the most likely causative organism?
A. Campylobacter B. C. Difficile C. Bacillus cereus D. E. Coli E. Vibrio cholera
B. C. Difficile
A 20 year old medical student comes back from their holiday and presents to A&E with profuse diarrhoea of rice water appearance. There is no blood.
What is the most likely cause?
A. Entamoeba histolytica B. Staph aureus C. Bacillus cereus D. E. Coli E. Vibrio cholera
E. Vibrio cholera
A 40 yo woman presents to A&E with bloody, foul smelling diarrhoea. She went to a barbeque yesterday where she suspects she ate undercooked chicken. She has a fever and severe abdominal pain.
What is the most likely cause?
A. Campylobacter B. Shigella C. Bacillus cereus D. E. coli E. Salmonella
A. Campylobacter
For Human Herpes Viruses (HHV) 1-8, state the name of the virus and the clinical presentation
HHV-1 = HSV-1 (multiple presentations including temporal lobe encephalitis) HHV-2 = HSV-2 (genital herpes) HHV-3 = VZV (chicken pox, shingles) HHV-4 = EBV (mononucleosis) HHV-5 = CMV (mononucleosis in immunocompromised) HHV-6+7 = roseola infantum HHV-8 = Kaposi's sarcoma
Define HSV
Disease resulting from HSV1 (mouth) or HSV2 (genitals) infection.
Summarise the epidemiology of HSV
VERY COMMON – 90% adults seropositive for HSV1 by 30 years (can be asymptomatic)
What are the two phases of HSV infection?
Virus becomes dormant following primary infection – trigeminal/sacral root ganglia.
Reactivation may occur in response to stress or immunosuppression (HIV)
Latent phase: Chronic infection where infectious virions are not produced –> Asymptomatic
Lytic phase: Viral replication and transport of virus to skin –> Active infection
Define VZV
HHV-3
Primary infection is called varicella (chickenpox).
Reactivation of the dormant virus in the dorsal root ganglia, causes zoster (shingles).
epidemiology of VZV
Chickenpox peak incidence: 4–10 years
Shingles peak incidence: >50 years.
About 90% of adults are VZV IgG positive.
VZV presentation- chicken pox
Prodromal malaise
Mild pyrexia
Generalised pruritic, vesicular rash - face and trunk predominantly
Contagious from 48 h before the rash and until all the vesicles have crusted over (within 7–10 days).
VZV presentation- shingles
May occur due to stress
Tingling in a dermatomal distribution- unilateral
Followed by painful skin lesions.
The skin remains painful until after the rash has gone
Recovery in 10–14 days.
How is VZV chickenpox managed?
Treat symptoms:
Calamine lotion- for itching
Analgesia- paracetamol
Antihistamines- diphenhydramine
How is VZV chickenpox in ADULTS managed?
Consider Aciclovir, valaciclovir or famciclovir if within 24 h of rash onset
otherwise treat symptoms
How is shingles managed?
1st line: Valaciclovir or famciclovir
2nd line: Aciclovir
… if within 72 h of appearance of the rash for 7 days
When is the VZV vaccine considered?
VZIG may be indicated:
immunosuppressed
Pregnant women exposed to varicella zoster
…if not previously immune
complication of shingles
Postherpetic neuralgia
Which drug is contraindicated in infectious mononucleosis?
Amoxicillin or ampicillin is CONTRAINDICATED due to widespread maculopapular rash
Prognosis of mononucleosis
Most make an uncomplicated recovery in 3–21 days.
How does hairy leukoplakia present?
Irregular, white, PAINLESS plaques on lateral tongue that cannot be scraped off.
ONLY in immunocompromised
Define candidiasis
Fungal infection caused by Candida species (Candida albicans) = thrush
dimorphic fungus
RFs for different types of candidiasis
Oral Candidiasis and Oesophageal thrush (Immunocompromised- neonates, steroids, diabetes, AIDS)
Vulvovaginitis (diabetes, use of antibiotics)
Diaper rash
Infective Endocarditis (IV drug users)
Disseminated candidiasis (especially in neutropenic patients
Signs and symptoms of oral /vaginal candidiasis
Oral Candidiasis and Oesophageal thrush =
Dysphagia
Vulvovaginitis/ Balanitis =
thick discharge, itching, soreness, redness
Diaper rash
Signs and symptoms of disseminated/systemic candidiasis
Endocarditis (IV drug users)
Disseminated candidiasis (in neutropenia) fever, hypotension +/- leucocytosis
Investigations for candidiasis
CLINICAL
Swabs no routinely recommended
Exclude DDx:
- Urinalysis (UTI)
- Random or fasting blood glucose (Diabetes)
- Glucose tolerance test (Diabetes)
- HIV antibody test
- Vaginal pH test (to exclude STIs)
Management of oral candidiasis
Miconazole oral gelandNystatin suspension
Management of vaginal candidiasis
intravaginal antifungal cream or pessary (clotrimazole, miconazole) or an oral antifungal (fluconazole or itraconazole).
Treatment of systemic candidiasis
Amphotericin B
State 3 HIV-associated tumours
- Kaposi’s sarcoma
Caused by HHV8 - Squamous cell carcinoma (particularly cervical or anal due to HPV)
- Lymphoma.
How does kaposi’s sarcoma present?
pink or violaceous (purple) patch on the skin or in the mouth.
Investigations for HIV
GOLD STANDARD: 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
Other tests for patients recently diagnosed with HIV
Drug resistance test – to determine therapy
Serum hepatitis B and C serology
Treponema pallidum haemagglutination test – screening for symphilis
Tuberculin skin test – TB
FBC, U+E, LFTs
Define tonsilitis
Acute infection of parenchyma of palatine tonsils. May occur in isolation or as part of generalised pharyngitis
Most common viral causes of tonsilitis
rhinovirus, coronavirus, adenovirus
Associated with IM infection
Most common bacterial causes of tonsilitis
Mycoplasma pneumoniae
Neisseria gonorrhoea
Group A streptococci
(sore throat after Big MNG)
Signs and symptoms of tonsilitis
Pain on swallowing Fever >38 Tonsillar exudate Sudden onset sore throat Tonsillar erythema and enlargement Anterior cervical lymphadenopathy
What type of tonsilitis is most common?
viral (90% adults, 70% children)
Summarise the epidemiology of tonsilitis
VERY common
especially children 5-15yrs
What score is used to diagnose group A strep (bacterial) tonsilitis?
FeverPAIN:
Fever (>38) during previous 24h
Purulence (pharyngeal, tonsillar exudate)
Attend rapidly (3 days or less after symptom onset)
Severely inflamed tonsils
No cough or coryza
(lymphadenopathy)
How does lymphadenopathy differ between EBV and tonsilitis?
EBV = posterial cervical Tonsilitis = anterior cervical
What criteria, other than FeverPAIN, is used to diagnose strep (bacterial) tonsilitis?
Centor criteria:
>=3 of following –> rapid strep antigen test
1. Tonsillar exudate
2. Tender anterior cervical lymphadenopathy or lymphadenitis
3.History of fever over 38
4. Absence of cough
define common cold
mild, self-limiting, viral, upper respiratory tract infection characterized by nasal stuffiness and discharge, sneezing, sore throat, and cough
What are the most common pathogens causing common cold?
Rhinoviruses (50%) Coronavirus (10-15%) Influenza (5-15%) Parainfluenza (5%) Respiratory syncytial virus (5%)- bronchiolitis in children
Investigations for common cold
Clinical diagnosis
Consider: FBC, Throat swab, Sputum culture, CRP, CXR
Signs and symptoms of common cold
Runny/blocked nose SNEEZING Sore throat Cough Headache Malaise and Fever. Usually clear within 7 to 10 days
Management of common cold
Supportive care – hydration, analgesic, antipyretic, decongestant (oxymetazozline nasal, ipratropium nasal) +/- antihistamine, antitussive
Most common cause of external (cutaneous + subcutaneous) abscess
Staph aureus
Common sites of internal abscesses
Lungs Brain Teeth Kidneys Tonsils Perianal abscesses – common in IBD and diabetes Incisional abscess
How is abscess diagnosed?
clinical, Ultrasound can help diagnosis
How is abscess managed?
small- aspiration
otherwise- incision + drainage
severe cases(cellulitis, sepsis)- excision + antibiotics
What is the name for a peritonsillar abscess?
quinsy
build-up of pus between one of your tonsils and the wall of your throat
Toxoplasma is associated with which animals?
cat faeces, undercooked pork
What pathology can toxoplasma cause in immunocompromised patients?
myocarditis, encephalitis, focal CNS signs, stroke, seizures
What is the classic head CT finding of someone with toxoplasma infection?
multiple, ring enhancing lesions
A 13-year-old female patient presents to A&E with difficulty speaking. 4 days ago she experienced a sore, painful throat, which progressively got worse. She has difficulty swallowing. On examination there is bilateral tonsillar exudate. There are 3 tender swellings on the anterior border of the sternocleidomastoid muscle and her observations are: T 39.1, HR 90, BP 113/68, SpO2 97% . What is the most likely diagnosis? Infectious mononucleosis Viral tonsillitis Common cold Bacterial tonsillitis Chickenpox
bacterial tonsilitis
> 3 on centor criteria
viral is posterior cervical + EBV has splenomegaly
A baby girl born 1 day ago born after a long vaginal labour, becomes drowsy. On examination, T: 38.9, HR: 170bpm, RR: 30. Which is the most likely causative agent?
Neisseria meningitis Streptococcus pneumonia Listeria monocytogenes Group B streptococcus E. Coli
Group B streptococcus
commonest cause of fever and drowsiness in neonates is meningitis
Prolonged rupture of membranes is more associated with Group B strep
15-year-old boy with DiGeorge syndrome had a dental tooth extraction 2 weeks ago, visits his GP who on auscultation finds a new onset murmur on the left sternal edge. Basic observations: BP 110/80, HR: 95, Temperature: 38.5, SaO2 98% on air. What is the most likely causative agent?
Staph aureus Staph epidermis Streptococcus viridian Streptococcus bovis Enterococci
Streptococcus viridian
DiGeorge patients have congenital heart defects.
Dental procedures may result in introduction of infection.
24 year old medical student comes back from their holiday and presents to A&E with profuse diarrhoea of rice water appearance. There is no blood. What is the most likely causative agent?
Entamoeba histolytica Staph aureus Bacillus cereus E. Coli Vibrio cholera
Vibrio cholera
40 year old woman presents to A&E with bloody, foul smelling diarrhoea. She went to a barbeque yesterday where she suspects she ate undercooked chicken. She has a fever and severe abdominal pain. What is the most likely causative agent?
Campylobacter – undercooked poultry
Salmonella is more associated with raw eggs
67 year old male has been in hospital for the past two weeks for severe pneumonia. He develops bloody diarrhoea, colitis and reduced urine output. He has raised CRP, WCC and low albumin. What is the most likely causative organism?
C. difficile
association with antibiotics suggested by the severe pneumonia and hospitalisation
Define meningitis
Inflammation of leptomeningeal (pia mater and arachnoid) coverings of the brain
Define encephalitis
Inflammation of brain parenchyma
Who does meningitis most commonly affect?
Affects extremes of age (impaired immunity)
What is the most common cause of encephalitis?
Virus- main = HHV
Can be infective or non-infective cause
Most common causative agents for meningitis
Most commonly bacterial:
- Streptococcus pneumoniae,
- Neisseria meningitidis
- Haemophilus influenzae type B
State some causes of aseptic meningitis
Characterised by clinical and laboratory evidence for meningeal inflammation and
negative routine bacterial cultures:
- enteroviruses (commonest)
- mycobacteria, fungi
- autoimmune (sarcoidosis, Bechet’s, SLE)
- malignancy (lymphoma, leukaemia, mets)
- iatrogenic (trimethoprim, NSAIDs, azathioprine)
symptoms of meningitis
MENINGISM:
Photophobia
Neck stiffness
Fever
Headache
symptoms of encephalitis
Altered state of consciousness seizures personality change cranial nerve palsies speech problems motor and sensory deficit
CONFUSION IS LESS COMMON IN MENINGITIS
Investigations for meningitis
Blood: Two sets of blood cultures
Imaging: CT scan to exclude intracranial pressure.
Lumbar puncture: Send CSF for MC&S and Gram staining
Investigations for encephalitis
Blood cultures
neuroimaging (MRI)
CSF analysis
immediate management of meningitis
Empirical antimicrobial therapy should be started promptly:
Ceftriaxone + Vancomycin
Consider corticosteroids –
Dexamethasone for bacterial meningitis
(unless meningococcal septicaemia is suspected)
What meningitis infection would you expect in neonates after an extended labour (+infection in previous infection)?
Group B streptococcus
What meningitis infection would you expect in late neonates? (few weeks post birth)
E. coli
What are the 3 common meningitis bacterial pathogens in neonates?
Group B strep
E. coli
Listeria monocytogenes
Most common bacterial causes of meningitis in children + teenagers
Neisseria meningitides (if vaccinated) Haemophilus influenzae (if unvaccinated)
What type of bacteria is Neisseria meningitides?
gram negative diplococci
What are the 2 commonest causes of meningitis in adults/elderly and what are they associated with?
most common = streptococcus pneumoniae
elderly, cheese/unpasteurised milk. alcoholics = Listeria monocytogenes
2 signs of meningism
Brudzinksi’s sign- severe neck stiffness causes a patients hips and knees to flex when neck is flexed
Kernig’s sign- severe stiffness of hamstrings causes inability to straighten leg when the hip is flexed to 90 degrees
signs of meningitis
Brudinski's and Kernig's signs fever tachycardia hypotension petechial rash- non-blanching = meningococcal septicaemia altered mental state
contraindications for lumbar puncture
Neurological signs suggesting raised ICP (CT head first)
Superficial infection over LP site
Coagulopathy
How would CSF results differ in appearance between different infectious causes of meningitis?
NORMAL = clear BACTERIAL = turbid VIRAL/TB/FUNGAL = clear/cloudy
Compare CSF results between different infectious causes of meningitis
WCC - normal = low - bacterial = neutrophils (aka granulocytes) - viral/TB/fungal = lymphocytes PROTEIN - bacterial = very high +++ - viral/TB/fungal = high + GLUCOSE - bacterial = very low --- - viral = normal - TB/fungal = low -
Bacterial will also have gram stain positive
If a patient presents with a non-blanching rash/meningococcal septicaemia + meningism how would you manage them?
This is NEISSERIA MENINGITIDES
Admit
give single IV dose of benzylpenicillin
What antibiotic would you give for suspected Lisseria meningitis?
ampicillin
If a meningitic patient presents with impaired consciousness, what drug would consider giving and why?
suspect meningo-encephalitis
IV acyclovir
most common cause of encephalitis is HHV
What prophylactic drugs would you give to people exposed to meningitis?
Rifampicin
Fungal causes of encephalitis
Cryptococcus, candida
Parasitic causes of encephalitis
Toxoplasma gondii, malaria
Define infective endocarditis
Infection of endocardial structures (mainly heart valves)
Most common causes of infective endocarditis? For each pathogen, state the associated RF
Streptococci (40%)- abnormal heart valves- congenital, post rheumatic, degenerative/calcification (viridans/bovis)
Staphylococci (35%)- prosthetic heart valves (S.aureus), IV drug users (S.epidermis)
Enterococci(20%)- E. faecalis.
Which organisms may test negative on culture in infective endocarditis?
HACEK
(Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella),
Coxiella burnetii, histoplasma
RF for infective endocarditis
Abnormal valves (e.g. congenital, post-rheumatic, calcification/ degeneration) Prosthetic heart valves IV drug use Turbulent flow (e.g. PDA or VSD), Recent dental work
which valve is most likely to be affected in IVDU associated endocarditis?
first valve in contact with venous system- tricuspid
Which infective endocarditis causative organism is associated with GI malignancy?
Streptococcus Bovis
symptoms of infective endocarditis
Fever with sweats/chills/rigors (may be relapsing and remitting).
Malaise, arthralgia, myalgia, confusion (particularly in elderly).
Skin lesions- Osler’s nodes (tip of the finger/toes, painful) + Janeway lesions (palm and soles, non-painful.)
Inquire about recent dental surgery or IV drug abuse.
signs of infective endocarditis
- Pyrexia, tachycardia, signs of anaemia.
- New regurgitant murmur or muffled heart sounds (right-sided lesions may imply IV drug use).
- Splenomegaly.
- Vasculitic lesions: Petechiae particularly on retinae (Roth’s spots), pharyngeal and conjunctival mucosa
HANDS
- Janeway lesions (painless palmar macules, which blanch on pressure);
- Osler’s nodes (tender nodules on finger/toe pads)
- Splinter haemorrhages (nail-bed
haemorrhages)
- Clubbing (if long-standing).
What mnemonic can be used to remember the signs of infective endocarditis?
FROM JANE with ♥:
Fever Roth spots Osler nodes Murmur Janeway lesions Anaemia Nail-bed haemorrhage Emboli
What hand sings may you see of infective endocarditis?
JANEWAY LESIONS- painless, blanching palmar macules
OSLER’S NODES- painful, tender nodules on finger/toe pads
SPLINTER HAEMORRHAGE
Buzzwords for infective endocarditis
- prosthetic valve
- dental procedures (strep)
- new onset murmur
- vegetation on echo
- right heart (IVDU)
- indwelling catheter
Investigations for infective endocarditis
Bloods: FBC (high neutrophils, normocytic anaemia), ESR and CRP, U&Es, RF (RA can cause)
3 blood cultures, 1 h apart, within 24 hs
Urgent echo
Dukes classification
Broad spectrum antibiotics until sensitivity reported
What classification is used to diagnose infective endocarditis?
Duke’s classification: (2 major, 1 major + 3 minor, all minor).
Major criteria:
Positive blood culture in two separate samples.
Positive echocardiogram
(vegetation, abscess, prosthetic valve dehiscence, new valve regurgitation).
Minor criteria:
High-grade pyrexia (temperature >38$C)
Risk factors (abnormal valves, IV drug use, dental surgery).
Vascular signs.
complications of infective endocarditis
Congestive heart failure Valve incompetence Aneurysm formation Systemic embolization Renal failure Glomerulonephritis.
Management of infective endocarditis?
Antibiotics for 4-6 weeks
NATIVE VALVES
Penicillin-sensitive Streptococcus viridans = Benzylpenicillin + gentamicin
S. aureus = Flucloxacillin
PROSTHETIC VALVES
Staphylococci = Flucloxacillin + rifampicin + gentamicin (stronger set because prosthetic bacteria stronger)
if penicillin allergic- replace with vancomycin
Define gastroenteritis
Acute inflammation of the lining of the GI tract, manifested by nausea, vomiting, diarrhoea and abdominal discomfort.
Most common causes of viral gastroenteritis
Rotavirus (children, decreasing due to vaccine)
adenovirus
astrovirus
calcivirus
Most common causes of bacterial gastroenteritis
Campylobacter jejuni E.coli Salmonella Shigella Vibrio cholerae Listeria Yersinia enterocolitica.
Most common causes of protozoal gastroenteritis
Entamoeba histolytica
Cryptosporidium parvum
Giardia lamblia
What pathogens might be present in undercooked meat?
S. aureus, C. perfringens
What pathogens might be present in old rice?
B. cereus, S. aureus
What pathogens might be present in milk + cheese?
Listeria, Campylobacter
What pathogens might be present in canned food?
botulism
Diarrhoea versus dysentry
dysentry = bloody diarrhoea
Which pathogens can cause dysentry? (CHESS)
CHESS: Campylobacter / Clostridium difficile Haemorrhagic E. coli Entamoeba histolytica Shigella Salmonella
What 2 categories of toxin can be produced to create inflammatory/non-inflammatory diarrhoea?
ENTEROTOXINS- non-inflammatory- cause enterocytes to secrete water and electrolytes (V. cholerae, enterotoxigenic E. coli)
CYTOTOXINS- inflammatory- invade and damage epithelium (Shigella, enteroinvasive E. coli), can cause bacteraemia (salmonella)
Which bacteria is responsible for diarrhoea after antibiotic use?
C. difficile
Which bacteria is responsible for short-lived diarrhoea 1-6 hours after eating?
Staph aureus
Which bacteria is responsible for rice-water diarrhoea with poor sanitisation + shock?
Vibrio cholera
Which bacteria is responsible for diarrhoea after eating leafy vegetables?
E. Coli
also haemorrhagic E.coli = dysentry followed by HUS
Which bacteria is responsible for diarrhoea after eating reheated rice? What else can it cause?
Bacillus cereus
can cause cerebral abscess
Which bacteria responsible for diarrhoea is found in eggs?
Salmonella
multiplies in Payer’s patches of the intestine
Which bacteria responsible for diarrhoea is found in poultry?
Campylobacter
Shigella is associated with what?
person-person contact
MSM
Gastroenteritis symptoms
Sudden onset nausea Vomiting Anorexia. Diarrhoea (+/- blood) Abdominal pain Fever and malaise.
Investigations for gastroenteritis
Examination:
Mucous membranes, skin turgor, cap refill –>dehydration?
HR, BP –> shock?
Temperature
Bloods: FBC, ESR/CRP, U&Es - deranged (low K in severe D&V)
Stool MC&S: Bacterial pathogens, Ova cysts (eggs), Parasites
Management of gastroenteritis with no systemic illness (fever, shock, dysentry, >2 weeks)
Supportive therapy
Bed rest, fluids and electrolyte replacement with oral rehydration solution
No stool culture needed
Management of gastroenteritis with systemic illness (fever, shock, dysentry, >2 weeks)
Admit and give oral fluids
(IV rehydration for severe vomiting)
Antibiotics if infective organism identified
Direct faecal smear, then culture
37-year-old bride-to-be returned from Jamaica 3 days ago, where she partied and explored the local cuisine with her best friends. She presents to her GP complaining of being jaundiced with right upper quadrant pain and fever. She has raised ALT and AST. What is the most likely cause of her symptoms?
Alcoholic hepatitis Gall stones Cholecystitis Hepatitis A Hepatitis C
Hepatitis A
Jaundice, RUQ pain & raised ALT & AST is suggestive of Hepatitis.
Jamaica is an endemic country and Hepatitis A is faeco-orally transmitted
A 64-year-old male with thalassaemia is investigated under the two-week wait for jaundice, hepatomegaly and weight loss. His blood tests show a raised αFP. Which chronic infection is he most likely to have?
A. Hepatitis A B. Hepatitis B C. Hepatitis C D. Hepatitis D E. Hepatitis E
Hepatitis C
The combination of jaundice, hepatomegaly and weight loss, when combined with a raised aFP, points to a diagnosis of hepatocellular carcinoma.
HBV and HCV can cause chronic infection, but HCV is more likely
35-year-old woman presenting to her GP with increased urinary frequency and lower back pain. On examination her BP is 130/90, HR: 83bpm, RR: 17bpm and T: 38.3. Which is the most likely finding on her urine dip stick and MC&S?
This is the clinical picture of UTI. Urine dipstick will show positive nitrites and leukocytes.
E.Coli is the most common cause and it is a gram negative bacilli
A 45-year old man presented to his GP with cyclical fevers. He returned from Ethiopia 10 days ago. What is the most likely causative agent?
Salmonella typhi Yersinia pestis Leptospirosis Plasmodium falciparum Coxiella burnetii
Malaria is associated with endemic areas and cyclical fevers
Causative organism is Plasmodium falciparum.
Salmonella causes dysentery
Y. Pestis causes plaque
Leptospira is due to water contaminated with animal urine
Coxiella burnetti causes Q fever
Define hepatitis
Inflammatory liver injury
Signs and symptoms of hepatitis
Fever
Jaundice
Raised ALT, raised AST
common causes of hepatitis
Viral A, B, C, D, E
Alcoholic
Autoimmune
Investigations for viral hepatitis
Blood:
FBC
LFTs (bilirubin, albumin, AlkPhos, GGT).
U&E
Clotting: Prolonged PT is a sensitive marker of significant liver damage.
Ultrasound scan: For other causes of liver impairment (e.g. malignancies).
Viral serology
Viral PCR
Liver biopsy: To assess degree of inflammation and liver damage (useful in diagnosing cirrhosis as patients)
Which hepatitis are faeco oral?
A+E
Faeco-oral hepatitis = The vowels hit your bowels
Hep A common history features
Acute- Travel history (contaminated water is a major source)
Asymptomatic (usually)
Hep A symptoms
Nausea Vomiting (+ Diarrhoea) Fever Jaundice Abdominal pain (particularly RUQ)
Hep A treatment
supportive, and alcohol should be avoided.
There is a small risk of acute liver failure, which necessitates the need for liver transplantation
risks of chronic HEV infection are high for which group?
HEV infection is usually acute and self-limiting. immunocompromised patients (including organ transplant recipients on immunosuppressants) are at risk of chronic infection.
HAV is common in which areas/foods?
Outbreaks are more common in Asia and Africa
improperly cleaned shellfish from contaminated water can be source of HAV
MSM
Acute HBV symptoms
Nausea, Anorexia, RUQ pain, Jaundice
How is HBV spread?
vertical mother-child transmission, contaminated blood products and sexually.
HBV vs HCV
HBV and HCV present similarly. however: HBV = only 10% chronic HCV = chronic, increased HCC risk HBV = DNA, HCV = RNA HCV = blood transmitted, HBV = more commonly sexually transmitted
which hepatitis is RF for HCC?
HCV
Treatment of HCV
Antiretrovirals are now curative e.g.
Sofosbuvir (NS5B inhibitors)
Ledipasvir (NS5A inhibitors)
Grazoprevir (NS3/4 protease
Define UTI
Characterized by presence of>100,000 of colony-forming units per millilitre of urine. UTI may affect bladder (cystitis), kidney (pyelonephritis) or prostate (prostatitis).
cystitis signs
Frequency, Urgency, Dysuria
Haematuria.
Foul-smelling ± cloudy urine.
Suprapubic or loin pain.
pyelonephritis signs
Rigors.
Pyrexia.
Nausea ± vomiting.
Acute confusional state elderly.
Common pathogens causing UTI
Escherichia coli = most common
Proteus mirabilis
Klebsiella
Enterococci
Investigations for UTI
Assess RF
Dipstick urinalysis: positive nitrites (E.coli specific) +/- leukocytes
Urine MC&S
(Abdo USS – exclude urinary tract obstruction or renal stones)
RF UTI
female, recent instrumentation, abnormality, incomplete bladder emptying, sexual activity, new sexual partner, diabetes, catheter, pregnancy
management of UTI
Trimethoprim/ Nitrofurantoin
E.coli UTI causes what positive dipstick result?
nitrites
Define malaria
Infection with protozoan Plasmodium
Causative organisms for malaria
Plasmodium spp
P. vivax/ovale
P. falciparum
P. malaria
Incubation period of malaria
Incubation usually 1-2 weeks but up to a year
organisms responsible for transmission of malaria
female Anopheles mosquito
Symptoms of malaria
Headache Weakness Myalgia/ Arthralgia Anorexia Fever - Characteristic paroxysms of severe cold / rigors followed by severing sweating
Signs of malaria
Pyrexia
Anaemia
Splenomegaly
Investigations for malaria
Giemsa-stained thick and thin blood smears
Thick – detects parasites present
Thin – identifies species
Other: FBC (Hb, platelets), Clotting profile, U+E, LFTs, blood glucose, Urinalysis, ABG