ID II Flashcards
What is kaposi’s sarcoma caused by
HHV-8(human herpes virus 8)
How does kaposi’s sarcoma present
Purple papules or plaques on the skin or mucosa
skin lesions may later ulcerate
respiratory involvement may cause massive haemoptysis and pleural effusion
What type of virus is HIV
RNA retrovirus
HIV-1 most common
Disease progression of HIV
An initial seroconversion flu-like illness occurs within a few weeks of infection.
The infection is then asymptomatic until it progresses and the patient becomes immunocompromised and develops AIDS-defining illnesses and opportunistic infections potentially years later.
Transmission of HIV
Unprotected anal, vaginal or oral sexual activity.
Mother to child at any stage of pregnancy, birth or breastfeeding. This is referred to as vertical transmission.
Mucous membrane, blood or open wound exposure to infected blood or bodily fluids such as through sharing needles, needle-stick injuries or blood splashed in an eye.
AIDS-defining illnesses associated with end-stage HIV
Kaposi's sarcoma PCP CMV Candidiasis(oesophageal or bronchial) Lymphomas TB
How long can antibody tests be negative for following exposure to HIV
Antibody tests can be negative for 3 months following exposure so repeat testing is necessary
Testing for HIV
Antibody test
p24 antigen test(can give positive result earlier in infection in comparison with antibody test)
PCR testing for HIV RNA
normal CD4 range and abnormal range
500-1200 cells/mm3 is the normal range
Under 200 cells/mm3 is considered end stage HIV / AIDS and puts the patient at high risk of opportunistic infections
Treatment for HIV
Combination of antiretroviral therapy
Association between HIV and cardiovascular disease
HIV infection increases the risk of developing cardiovascular disease. Patients with HIV have close monitoring of cardiovascular risk factors and blood lipids and appropriate treatment (such as statins) to reduce their risk of developing cardiovascular disease.
Why is co-trimoxazole given to HIV patients with CD4<200/mm^3
Prophylactic co-trimoxazole (Septrin) is given to patients with CD4 < 200/mm3 to protect against pneumocystis jirovecii pneumonia (PCP).
Why are yearly cervical smears required for women with HIV
HIV predisposes to developing cervical human papillomavirus (HPV) infection and cervical cancer so female patients need close monitoring to ensure early detection of these complications.
Risk factors for HIV
Have a current or former partner who is infected with HIV.
Are from an area with high HIV prevalence
MSM
Transwomen
IVDU
Sex workers
Blood transfusions
Adverse effects of ART in HIV
Hypersensitivity(fever,rash) Mood changes Peripheral neuropathy Hyperlipidaemia T2DM
How quickly should PEPSE be initiated in a person with exposure to HIV
PEPSE can be initiated if the person presents within 72 hours of exposure and should be given as early as possible (ideally within 24 hours of exposure).
HIV testing is recommended 8–12 weeks after exposure.
Common causes of intra-abdominal infections
Anaerobes (e.g. bacteroides and clostridium) E. coli Klebsiella Enterococcus Streptococcus
Co-amoxiclav cover
This provides good gram positive, gram negative and anaerobic cover. It does not cover pseudomonas or atypical bacteria.
Quinolones cover
Ciprofloxacin and levofloxacin provide reasonable gram positive and gram negative cover and also cover atypical bacteria however they don’t cover anaerobes so are usually paired with metronidazole when treating intra-abdominal infections.
Metronidazole cover
This provides exceptional anaerobic cover but does not provide any cover against aerobic bacteria.
Gentamicin cover
This provides very good gram negative cover with some gram positive cover particularly against staphylococcus.
It is bactericidal so works to kill the bacteria rather than just slowing it down.
Vancomycin cover
This provides very good gram positive cover including MRSA. It is often combined with gentamicin (to cover gram negatives) and metronidazole (to cover anaerobes) in patients with penicillin allergy.
Cephalosporins cover + why are they sometimes avoided
These provide good broad spectrum cover against gram positive and gram negative bacteria but are not very effective against anaerobes.
They are often avoided due to the risk of developing C. difficile infection.
Management of SBP
Piperacillin/Tazobactam (Tazocin) is often first line
Which patients often present with SBP
Patients with liver failure
Examples of gram-positive cocci
Staphylococcus
Streptococcus
Enterococcus
Examples of gram-positive rods
Use the mnemonic “corney Mike’s list of basic cars”:
Corney – Corneybacteria Mike’s – Mycobacteria List of – Listeria Basic – Bacillus Cars – Nocardia
Examples of gram positive anaerobes
Use the mnemonic “CLAP”:
C – Clostridium
L – Lactobacillus
A – Actinomyces
P – Propionibacterium
Antibiotic treatment options for MRSA
Doxycycline
Clindamycin
Vancomycin
What are ESBLs
Extended Spectrum Beta Lactamase bacteria
bacteria that have developed resistance to beta-lactam antibiotics(e.coli or klebsiella)
Management of ESBLs
Carbapenems
Staining to identify TB
They require a special staining technique using the Zeihl-Neelsen stain.
How does TB spread
It is mostly spread by inhaling saliva droplets from infected people.
It then spreads through the lymphatics and blood
Active vs latent TB
Active TB is where there is active infection in various areas within the body. In the majority of cases the immune system is able to kill and clear the infection.
The immune system may encapsulate sites of infection and stop the progression of the disease and this is referred to as latent TB.
What is secondary TB
When latent TB reactivates this is known as secondary TB
Features of infected lymph nodes in TB
A “cold abscess” is a firm painless abscess caused by TB, usually in the neck. They do not have the inflammation, redness and pain you would expect from an acutely infected abscess.
Risk factors for TB
Known contact with active TB
Immigrants from areas of high TB prevalence
People with relatives or close contacts from countries with a high rate of TB
Immunosuppression due to conditions like HIV or immunosuppressant medications
Homeless people, drug users or alcoholics
What is the BCG vaccine
The BCG vaccine involves an intradermal infection of live attenuated (weakened) TB.
It offers protection against severe and complicated TB but is less effective at protecting against pulmonary TB.
Tests prior to BCG vaccine
patients are tested with the Mantoux test and given the vaccine only if this test is negative. They are also assessed for the possibility of immunosuppression and HIV due to the risks related to a live vaccine.
TB presentation
Lethargy Fever or night sweats Weight loss Cough with or without haemoptysis Lymphadenopathy Erythema nodosum Spinal pain in spinal TB (also known as Pott’s disease of the spine)
What is the Mantoux test used for
To look for a previous immune response to TB. This indicates possible previous vaccination, latent or active TB.
What does the IGRA test involve
This test involves taking a sample of blood and mixing it with antigens from the TB bacteria.
In a person that has had previous contact with TB the white blood cells have become sensitised to those antigens and they will release interferon-gamma as part of an immune response.
If interferon-gamma is released from the white blood cells then this is considered a positive result.
When is the IGRA test used
The IGRA test is used in patients that do not have features of active TB but do have a positive Mantoux test to confirm a diagnosis of latent TB.
Management of latent TB
Otherwise healthy patients do not necessarily need treatment for latent TB.
Patients at risk of reactivation of latent TB can be treated with either:
Isoniazid and rifampicin for 3 months
Isoniazid for 6 months
Management of acute pulmonary TB
R – Rifampicin for 6 months
I – Isoniazid for 6 months
P – Pyrazinamide for 2 months
E – Ethambutol for 2 months
Notable side effect of isoniazid
Peripheral neuropathy
What should be co-prescribed with TB meds
Pyridoxine(vitamin B6)
What type of rooms are used for patients with active TB
Negative pressure rooms are used to prevent airborne spread. Negative pressure rooms have ventilation systems that actively remove air to prevent it spreading out on to the ward
How is treatment different for extra pulmonary TB
Can include using corticosteroids
Notable side effects of rifampicin
Can cause red/orange discolouration of secretions like urine and tears. It is a potent inducer of cytochrome P450 enzymes therefore reduces the effect of drugs metabolised by this system.
This is important for medications such as the contraceptive pill.
Notable side effect of pyrazinamide
Pyrazinamide can cause hyperuricaemia (high uric acid levels) resulting in gout.
Notable side effects of ethambutol
Ethambutol can cause colour blindness and reduced visual acuity.
What type of virus is influenza
RNA virus
Presentation of influenza
Fever Coryzal symptoms Lethargy and fatigue Anorexia (loss of appetite) Muscle and joint aches Headache Dry cough Sore throat
Diagnosis of influenza
Viral nasal or throat swabs can be sent to the local virology lab for polymerase chain reaction (PCR) analysis.
General management of influenza
Healthy patients that are not at risk of complications do not need treatment with antiviral medications. The infection will resolve with self care measures such as adequate fluid intake and rest.
Antiviral options for influenza
Oral oseltamivir 75mg twice daily for 5 days
Inhaled zanamivir 10mg twice daily for 5 days
Within 48hrs of onset of symptoms to be effective
Complications of influenza
Otitis media, sinusitis and bronchitis Viral pneumonia Secondary bacteria pneumonia Worsening of chronic health conditions such as COPD and heart failure Febrile convulsions (young children) Encephalitis
Dengue fever aetiology
dengue virus is a RNA virus of the genus Flavivirus
transmitted by theAedes aegyptimosquito
Dengue fever clinical features
fever
headache (often retro-orbital)
myalgia, bone pain and arthralgia (‘break-bone fever’)
pleuritic pain
facial flushing (dengue)
maculopapular rash
haemorrhagic manifestations e.g. positive tourniquet test, petechiae, purpura/ecchymosis, epistaxis
Dengue fever warning signs
abdominal pain
hepatomegaly
persistent vomiting
clinical fluid accumulation (ascites, pleural effusion)
Features of severe dengue fever
this is a form of disseminated intravascular coagulation (DIC) resulting in:
thrombocytopenia
spontaneous bleeding
around 20-30% of these patients go on to develop dengue shock syndrome (DSS)
Typical blood results in dengue fever
leukopenia, thrombocytopenia, raised aminotransferases
Dengue fever diagnosis
serology
nucleic acid amplification tests for viral RNA
NS1 antigen test
Dengue fever mx
entirely symptomatic e.g. fluid resuscitation, blood transfusion etc
no antivirals are currently available
