Infectious Disease Flashcards
What is Toxoplasmosis?
Toxoplasmosis is a parasitic disease whose main reservoir is in cats.
Caused by the parasite Toxoplasmosis gondii protozoa that infects the body via GI tract, lung or broken skin.
It’s oocysts release trophozoites which migrate widely around the body including to the eye, brain and muscle
Toxoplasmosis Px?
Flu-like illness
Malaise, lymphadenopathy + myalgia
Can be asymptomatic
Most healthy individuals will clear the infection but it can cause complications of anaemia, seizure or chorioretinitis.
These mainly occur in neonates (born to mothers with acute infection) or immunocompromised patients.
What is the treatment for Toxoplasmosis?
None in normal people
Pyrimethamine and sulphadiazine in immunocompromised pts
What is Leptospirosis?
Leptospirosis is a disease caused by the spirochaete Leptospira interrogans (serogroup L. icterohaemorrhagiae), spread by contact with infected rat urine.
Commonly seen in sewage workers, farmers, etc or those working in abattoir.
Also common in the tropics, so may mention returning traveller.
What are the features of Leptospirosis?
Early phase is due to bacteraemia + lasts a week
- may be mild/subclinical
- flu-like symptoms
- subconjunctical suffusion (redness)/haemorrhage
Second immune phase may lead to more severe dx (Weil’s disease)
- AKI (in 50% of pts)
- Hepatitis: jaundice, hepatomegaly
- Aseptic meningitis
Leptospirosis management?
Mild: Doxycycline
Severe: IV Benzylpenicillin or Ceftriaxone.
What Abx do you use for animal bites?
Co-Amoxiclav
If penicillin-allergic then doxycycline + metronidazole is recommended
What Abx do you use for skin and ear conditions?
Flucloxacillin
What is Vancomycin used to treat?
Gram-positive infections, particularly methicillin-resistant Staphylococcus aureus (MRSA).
What organism is most commonly found in animal bite wounds?
Pasteurella multocida
What are the most common organisms found in human bite wounds?
Streptococci spp. Staphylococcus aureus Eikenella Fusobacterium Prevotella
What Abx do you give to a pt presenting with a human bite?
Co-Amoxiclav
What is the causative organism of Gonorrhoea?
Neisseria gonorrhoea (a Gram -ve diplpcoccus)
What is the incubation period of gonorrhoea?
2-5 days
What are the features of gonorrhoea?
- Males: urethral discharge, dysuria
- Females: cervicitis e.g. leading to vaginal discharge
- Rectal and pharyngeal infection is usually asymptomatic
Management of gonorrhoea?
A single dose of IM Ceftriaxone
(If the organism has a known sensitivity to ciprofloxacin then this should also be given)
If injection refused, give oral Cefixime + oral azithromycin.
What is the most common cause of septic arthritis in young adults?
Gonorrhoea
What is Disseminated gonococcal infection (DGI)?
Haematogenous spread of mucosal gonorrhoea (genital infection).
Px as triad of:
- Tenosynovitis
- Migratory poly arthritis
- Dermatitis
Later complications include septic arthritis, endocarditis and peri-hepatitis (Fitz-Hugh-Curtis syndrome)
What type of herpes simplex virus causes Genital herpes?
HSV 2
What type of herpes simplex virus causes cold sores?
HSV 1
What is the causative organism of Syphilis?
The spirochaete ‘Treponema pallidum’
What is the incubation period of the primary stage of Syphilis?
9-90 days
Px as a painless ulcer
What is Chancroid?
Chancroid is a tropical dx caused by Haemophilus ducreyi.
What is the Px of Chancroid?
Painful genital ulcers associated with unilateral, painful inguinalLN involvement.
Ulcers have sharply defined, ragged, undermined border.
What is the causative organism of Lymphogranuloma venereum (LGV)?
Chlamydia trachomiatis.
What are the stages of infection in Lymphogranuloma venereum (LGV)?
- small painless pustule which later forms an ulcer
- painful inguinal lymphadenopathy
- proctocolitis
What is the treatment for LGV?
Doxycycline
What is the treatment for Syphilis?
IM Benzathine penicillin is 1st line
Doxycycline is an alt.
What is a common complication of Syphilis treatment?
The Jarisch-Herxheimer reaction.
- Px as fever, rash + tachycardia after 1st dose.
- Unlike anaphylaxis, no wheeze or hypotension.
- Due to endotoxins following bacterial death
- Occurs a few hrs after treatment
- No Rx needed (if pyrexial, tie anti-pyretics)
E.Coli typical Px?
Common amongst travellers
Watery stools
Abdominal cramps and nausea
Giardiasis typical presentation?
Prolonged, non-bloody diarrhoea
Cholera typical Px?
Profuse, watery diarrhoea.
Severe dehydration resulting in weight loss
Not common amongst travellers
Shigella typical Px?
Bloody diarrhoea
Vomiting and abdominal pain
Staphylococcus aureus typical Px?
Severe vomiting
Short incubation period
Campylobacter typical Px?
A flu-like prodrome is usually followedby cramping abdominal pains, fevered diarrhoea (may be bloody)
May mimc appendicitis
Complications include Guillain-Barre syndrome
Bacillus cereus typical Px?
2 types:
- vomiting within 6hrs, typically due to rice
- diarrhoea illness after 6hrs of rice
Amoebiasis typical Px?
Gradual onset bloody diarrhoea, abdominal pain + tenderness which may last for several weeks
Which infections have an incubation time of 1-6hrs?
Staphylococcus aureus + Bacillus cereus (vomiting subtype)
Which infections have an incubation time of 12-48hrs?
Salmonella + E.Coli
Which infections have an incubation time of 48-72hrs?
Shigella + Campylobacter
Which infections have an incubation time of >7days?
Giardiasis + Amoebiasis
What is the management of TB?
RIPE:
Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol.
*NOTE: 1st 3 can cause hepatitis, and Ethambutol can cause optic neuritis(E for Eye)
What are the features of yellow fever?
Biphasic.
- Abrupt headache, fever, malaise, myalgia lasting 3-4 days. Most recover at this point.
- Severe cases: back pain, N+V, jaundice, hepatitis, bleeding, rashes
What is the distribution of effect of yellow fever?
Sub-saharan Africa + South America
Mosquitos carry it.
NB not asia
Yellow fever management?
Supportive –> manage fluid balance, coaulopathy, renal insufficiency
There is a vaccine for it.
Dengue virus features?
Asymptomatic in 80% of kids.More severe in adults.
Abrupt fever, headache, myalgia, rash.
Can develop Dengue Shock Syndrome
What is the Px of Dengue shock syndrome?
Reduced perfusion, central cyanosis, sweating.
Petechiae, pleural effusions, ascites.
Encephalopathy, hepatic/heart/renal failure.
Dengue virus distribution in world?
South East Asia
South/Central America
Sub-Saharan Africa.
Mosquitos are vector.
Dengue fever management?
Supportive –> manage fluid balance, coaulopathy, renal insufficiency
There is NOT a vaccine for it.
What causes glandular fever?
90% due to EBV, can be CMV or HHV6.
Spread via saliva, semen or blood.
What is the classic Px triad of Glandular fever?
- Sore throat
- Fever
- Lymphadenopathy
*NB: may also get splenomegaly, hepatitis, lymphocytosis, palatal petechiae, haemolytic anaemia
What is the infective organism in Lyme disease?
Borrelia burgdorferi (spirochaete) that is spread by ticks that must be attached for 2-3 days to cause infection.
Suspect if Q mentions North America, camping, hiking etc.
What are the features of Lyme disease?
Early features: erythema migracans rash (target lesions!), headache, lethargy, fever, arthralgia
Late features: cardio (heart block, myocarditis), neuro (facial nerve palsy, meningitis)
What is Botulism?
Botulism is a rare and potentially fatal illness caused by toxin produced by the bacteria Clostridium Botilinum.
It is spread via contaminated food (Eg tinned and IVDU
What are the clinical features of Botulism?
- Progressive descending flaccid paralysis, ataxia, diplopia
- Usually fully conscious, no sensory disturbance.
Botulism management?
ITU Involvement
Anti-botulism toxin
What is Tetanus?
Tetanus is an infection caused by the bacteria Clostridium Tetani.
The tetanus exotoxin inhibits GABA release
Usually enter body via a wound or due to umbilical stump infections.
What are the clinical features of Tetanus?
ROAST
R - Rigidity O - Opisthotonus (hyperextension) A - Autonomic dysfunction S - Spasms T - Trismus (lockjaw)
Tetanus management?
- Wound debridement
- ITU involvement e.g. ventilation
- IM human tetanus immunoglobulin
What are the clinical features of malaria?
Uncomplicated –> cyclical fever, malaise, headache, sweats, rigors
Severe –> coma, seizures, blackwater fever (haemolysis), hypoglycaemia, ARDS, DIC
Signs –> Pallor due to anaemia
Hepatosplenomegaly
Jaundice as bilirubin is released during the rupture of RBCs
What is the causative organism of Malaria?
Plasmodium family of protozoan parasites.
The most severe and dangerous type is Plasmodium falciparum, which causes 75% of UK malaria cases.
Spread by female Anopheles mosquitos
What are the types of malaria?
- Plasmodium falciparum is the most severe and dangerous form
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
Why do pts with malaria have cyclical fevers?
The parasites reproduce in the liver every 48hrs causing haemolytic anaemia, and there is a temp spike in the pt every time they do so.
Malaria incubation time?
1-4 wks
What is the management of malaria?
If falciparum malaria, admit as can deteriorate fast!
Oral options in uncomplicated malaria:
- Artemether with lumefantrine (Riamet)
- Proguanil and atovaquone - (Malarone)
- Quinine sulphate
- Doxycycline
Intravenous options in severe or complicated malaria:
- Artesunate. This is the most effective treatment but is not licensed.
- Quinine dihydrochloride
What anti-malarials are used as prophylaxis for travel into endemic areas?
Malarone (best)
Mefloquine
Doxycycline
What is Schistosomiasis?
An infection caused by helminths.
- Travel to Africa (EGYPT), Middle East.
- Exposure to freshwater (SNAILS)
Px of Schistosomiasis?
Haematuria, diarrhoea + fever.
Find eggs in urine/stool sample.
Can predispose you to squamous cell bladder cancer
What is Chagas disease?
Chagas is an infection caused by the protozoa, Trypansoma cruzi.
Travel to Central/South America.
Chagas disease Px?
Acute phase: asymptomatic except nodule (Chagoma) from kissing bug (triatomine).
Late phase: infects muscle, so myocarditis –> dilated cardiomyopathy, mega-oesophagus, and mega-colon.
BIG ORGANS!!
What is Leishmaniasis?
A parasitic disease caused by Leishmania spp spread by Sandflies.
Travel to South/Central America, Africa, India.
Leishmaniasis Px?
Types:
- Cutaneous - skin lesions
- Mucocutaneous - mucosal involvement
- Visceral - massive splenomegaly, hepatomegaly, grey skin (kala-azar)
What is sleeping sickness?
AKA Human African trypanosomiasis.
Sleeping sickness is a parasitic infection caused by Trypanosoma Brucei spread by the Tsetse fly.
Travel to Africa.
Sleeping sickness Px?
Early: Fever, nodule at infection site, lymphadenopathy.
Late: CNS involvement, reduced GCS, meningoencephalitis.
