Block 31 Week 7 Flashcards
CAP causes
CFs of pneumonia?
- fever
- cough
- chest pain
- increased resp rate
- crackles
- tachycardia
Ix for pneumonia?
- CXR - to confirm diagnosis/ look for complications e.g. effusions
- moderate/ severe:
- blood cultures
- viral swabs
supportive management of pneumonia?
- Analgesia
- IV fluids
- Oxygen as needed
- Prophylaxis for DVT / PE
pneumonia management - drainage?
- Drainage of effusion if empyema or severe symptoms
Tx of mild pneumonia?
- 1st line: amoxicillin
- alt: clarithromycin
- alt: doxycycline
moderate pneumonia - oral/ IV?
- 1st line: amoxicillin + clarithromycin
- alt: doxycyline
What can be used instead of clarithromycin or doxycycline in moderate pneumonia?
Moxifloxacin / Levofloxacin
severe pneumonia drugs are given?
IV
Severe CAP first line?
- 1st line: Co-amoxiclav + Clarithromycin
severe CAP alternatives?
- 1st line: Co-amoxiclav + Clarithromycin
- alt: Cefuroxime + Clarithromycin
- alt: Benzylpenicillin + Levofloxacin
transmission of COVID-19?
- Major route is respiratory droplets, generated by coughing, sneezing, talking
- Other routes include aerosols, contact with contaminated surfaces
CFs of Covid?
- Classical URTI symptoms, may progress to severe disease around day 10 of illness
moderate-severe Covid?
- Pronounced inflammatory / pro thrombotic state in critical cases
- Often little to find on examination
- cough, fever, SOB, fatigue, chest pain, muscle aches
Ix for Covid?
- Low lymphocytes / platelets
- AKI
- Higher d-dimer
RF for mortality from Covid?
- For invasively ventilated patients mortality is around 50%
- Age is the most consistent and largest risk
- Men have worse outcomes
- Ethnicity appears to be a marked risk
CXR for covid?
- clasically there is bilateral interstitial shadowing typical of viral pneumonia
- takes a long time to resolve - may have persistent shadowing/ fibrosis
supportive care in the management of Covid-19?
*Oxygen for hypoxia
*IV fluids
*VTE prevention
*Analgesia
Targeted treatment of covid-19?
*Anti viral - Remdesivir
*Anti inflammatory - Dexamethasone
primary TB?
- Typically mild or asymptomatic
- Mid/lower zone infiltrates, hilar adenopathy, pleural effusion
Secondary TB?
- Tuberculin skin test positive (confounded by BCG)
- IGRA testing
- No evidence of active disease
Post-primary TB?
- Active disease; cough, presence of AFB in sputum, fever ~50%, haemoptysis, malaise, anorexia, weight loss, breathlessness
- Signs of parenchymal disease uncommon until disease advanced
high incidence TB countries?
- india
- indonesia
- pakistan
- china
RF for TB?
- Place of birth
- HIV
- Prison inmates/staff,
- nursing homes
- homeless shelters,
- health care workers,
- substance abuse,
- immigrant centres & migrant workers camps
medical factors inc TB risk?
- under nutrition
- smoking
- cancer
- HIV
- taking illicit drugs
- alcoholism
social factors increasing risk of TB?
Single/widowed men, immigration, incarceration, homelessness
CXR of pulmonary TB?
- Upper lobes tend to be affected
- irregular shadowing
- cavitation
- thick irregular walls
microbiological diagnosis of TB?
- positive cultures for M.TB confirm the diagnosis of TB
- CEPHAID test - detects DNA specific to TB and rifampicin. Results obtained within 90 mins
Mdr-TB means TB resistant to?
isoniazid and rifampicin
contact tracing in TB?
- idenficiation of contacts of TB positive individuals
- national target is for 90% of people with infectious TB to have at least 5 contacts traced
- pre-entry screening programme for testing of active pulmonary TB in migrants from high incidence countries who apply for visas which reduces importation of active TB
INF-gamma tests?
- quantiferon TB gold - used in place of TB testing for previous infection
- not confounded by prior BCG vaccine
- main role is screening for latent disease
what does the INF-G test measure?
- measures cell mediated immune response by looking at INF-g released by T cells in response to TB antigens
TB drugs?
*Isoniazid
*Rifampin
*Pyrazinamide
*Ethambutol
RIPE
TB drug regimen?
- Rifampicin, +Isoniazid, +Pyrazinamide, +Ethambutol for 2 months
- Rifampicin/Isoniazid for 4 months
isoniazid mechanism?
- bactericidal
- blocks mycolic acid synthesis
isoniazid needs to be taken?
- absorption decreased by fatty acids: needs to be taken 4 hours after food and 1 hour before
Adverse effects of isoniazid?
- hepatitis
- neuropathy, reduced risk with pyroxidine (vit B6) supplements
rifampicin mechanism?
- bactericidal, inhbitis DNA-dependent RNA polymerase
which drug reduces abs or rifampicin?
pyrazinamide
adverse effects of rifampicin ?
- induction of P450 enzymes - increases breakdown of many drugs
- hepatitis
Pyrazinamide - ? is intrinsically resistant?
M bovis
Adverse events of pyrazinamide?
- GI upset and arthralgia - raised uric acid
- hepatotoxicity
ethambutol?
- weak bacteriostatic drug
- antacids affect absorption
Adverse effects of ethambutol?
Optic neuritis (increased risk with pre-existing eye disease and higher doses than standard regimen)
Adherence to drug Tx - RF?
- social risk factors
- previous TB
- MDR
TB drugs that require monitoring?
- rifampicin
- 2nd line are commonly monitored to avoid toxicity e.g. amikacin, cycloserine
Where are the highest TB rates?
- highest rates of TB in the most deprived groups
- london has the highest number of TB cases in England followed by the South of England
Tb is concentrated in the following groups:
- the urban poor
- alcoholics
- iV drug users
- homeless
- prison inmates
how is TB spread?
- inhalation of droplets
- Infectious particles aerosolized by coughing, sneezing or talking
- fomites not important
TB - when the antigen load is small?
- granuloma forms
TB - when antigen load is high?
- lymphcoytes, macrophages and granulocytes present is a less organized fashion
- tissue necrosis may be present - exudative reaction
pathogenesis of TB?
- caseating necrosis is unstable so it tends to liquify and discharge through the bronchial tree producing a TB cavity
- infectious materal from a cavity results in new exudative foci in other parts of the lung - bronchogenic spread
symtoms of PTB?
- include a productive, prolonged cough (duration of >= 3 weeks),
- chest pain,
- hemoptysis.
Systemic symptoms of TB
- Fever, chills, night sweats, appetite loss, weight loss, and easy fatigability
In primary TB, there’s rapid
destruction of bactera so the only remaining evidence of infection would be a postive skin test
What happens in post-primary TB?
- Immune deficiency including disease, drugs, old age, malnutrition, alcohol etc
- Reactivation as macrophage/granuloma break up
- Causes bronchial spread as necrosis occurs
EP TB - metastatic spread to any organ:
- Abdomen
- Bone
- Brain
- Muscle
- Retina
- Lymph Node
TB of the spine and kidney?
- TB of the spine may cause pain in the back
- TB of the kidney may cause blood in the urine.
when should EP TB be considered?
- Extrapulmonary TB should be considered in the differential diagnosis of ill persons who have systemic symptoms and who are at high risk for TB.
sputum collection in TB?
- 3 early morning specimens of sputum on 3 consecutive days
what else can be done to obtain TB specimens?
- bronchoscopy can be done if there’s suspicion of TB and the patient can’t cough up sputum
- Gastric aspiration can also be used to obtain specimens of swallowed sputum
other tests for TB patients?
- Testing for HIV
- hep B and C serologic tests if risks present
tests to do when TB Tx is initiated?
- AST
- ALT
- bilirubin
- ALP
- serum creatinine
- platelet count
- Visual acuity and color vision tests (when EMB used)
drug interactions with rifampicin
MDR-TB is more likely in:
- people who have a history of Tx with TB drugs
- contacts of ppl known to have drug resistant TB
- people from countries where prev of MDR TB is high
- Persons whose smears or cultures remain positive despite 2 months of therapy with TB drugs;
- Persons receiving inadequate treatment regimens for > 2 weeks.
extensively drug resistant TB?
- XDR-TB is resistant to fluoroquinoline and at least 3 of the second line drugs (capreomycin, kanamycin, and amikacin), in addition to MDR-TB.
Summary table of the second line therapies in TB Tx
CAP =
- refers to pneumonia contracted outside the hospital setting and includes those developing the condition in a nursing home
typical CAP?
- productive cough, fever, pleuritic chest pain
- most commonly caused by streptococcus pneumoniae
- can also be caused by haemophilus influenzae
Most common causitive agent of CAP?
1) streptococcus pneumoniae
2) haemophilus B
atypical pneumonias?
- These tend to have a more insidious, subacute onset. They often present with a combination of pulmonary and extrapulmonary symptoms
pathogens causing atypical pneumonias?
- Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae
HAP =
- contracted >48 hrs after hospital admission
causes of HAP?
- Gram-negative bacilli(e.g.Pseudomonas aeruginosa)
- Staphylococcus aureus
- Legionella pneumophila
Aspiration of pneumonia?
- caused by inhalation of oropharhngeal or gastric contents
- typically seen in patients with reduced conciousness level, NM disorders, oesophageal conditions, mechanical interventions such as endotracheal tubes
IC - bacterial pneumonia?
typical pathogens and non-tuberculosis mycobacterium.
IC - fungal pathogens?
Pneumocystis jirovecii, Aspergillus fumigatus and Cryptococcus neoformans.
IC - viral pathogens?
such as varicella zoster virus and cytomegalovirus should be considered.
IC - parisitic pathogens?
parasitic pneumonias are very rare and seen almost exclusively in the immunocompromised.
streptococcus pneumonia typically produces a ? pattern of consolidation
lobar
sputum
strep pneumonia typically gives?
- It classically gives rust coloured sputum and may be accompanied by the reactivation of cold sores.
- Urinary antigen tests may be used to diagnose the infection and is unaffected by antibiotics.
mycoplasma pneumoniae?
- lacks a cell wall
- tends to affect younger demographic
- occurs in cyclical epidemics
mycoplasma pneumonia causes pneumonia with a prolonged insidious onset that may exhibit EP features:
- Erythema multiforme
- Arthralgia
- Myocarditis, pericarditis
- Haemolytic anaemia
legionella pneumonia?
- gram negative
- may cause the atypical CAP (lobar) Legionnare’s disease
legionella - exposure to?
- It is encountered in those exposed to contaminated cooling systems, humidifiers and showers.