Tuberculosis Flashcards
Tb is an _________ pathogen
Airborne
What is the difference between Tb infection and TB disease?
TB infection is a condition in which a person is infected with TB bacteria but does not have active disease or symptoms, while
TB disease is a serious condition in which the bacteria are multiplying and causing active infection in the body, with symptoms and contagiousness.
Where will Tb normally be more prevalent in the lungs?
Apices
Why does Tb usually grow preferentially in the lung apices?
Tb is an aerobic pathogen
In the apices of the lungs there is generally more ventilation than perfusion meaning inhaled aerobic pathogens will thrive most here
Which type of bacteria is Tb?
Bacilli
Why does Tb involve gramuloma formation?
Tb can enter alveoli and enter macrophages.
To respond, the body walls off the infected macrophages in a granuloma
In people experiencing Tb symptoms, the body cannot hold the ________ within the _________
Infection
Granuloma
How long can a granuloma hold the infection of Tb at bay?
It can vary from days to years
A Tb infection can remain “dormant” for many years
Systemic symptoms of Tb include?
Weight loss, Erythema nodosum and night sweats
Respiratory symptoms of Tb include?
Cough, haemoptysis, breathlessness and upper zone crackles
If lower lobes are infected with Tb, what does this suggest?
The infection occured through blood spread (sepsis)
Tb does not just infect the lungs. What are some other complications of Tb?
known as extrapulmonary TB
- Meningeal Tb
- GI Tb
- Spinal Tb
- Cold abscesses
- Lymphadeopathy
- Pericardial - cardiac tamponade
- Renal
- Septic arthritis
- Adrenal - hypoadrenalism
Which type of stan can detect Tb?
Ziehl-Neelson
Describe the process by which Tb is identified through staining
- Tb is stained
- Alcohol and acid are added to remove the stain as far as possible
- The sample is washed with blue stain
- Any areas still red show presence of Tb which retains the original stain
Tb can be identified by staining, how else can it be identified?
PCR (polymerase chain reaction)
Culturing
The histology of Tb includes ___________ giant cell _________, _________ necrosis and potentially visible ___________
Multinucleate
Granulomas
Caseating
Mycobacteria
What is the treatment for Tb?
6 month antibiotic course
- 2 months of
- Rifampicin
- Isoniazid
- Pyrazinamide
- Ethambutol
Followed by
- 4 months of
- Rifampicin
- Isoniazid
What is a side effect of rifampicin?
It colours everything orange
(Bodily fluids, urine etc)
They noticed their urine or tears are orange or red: rifampicin (“red-an-orange-pissin’”).
What is a side effect of ethambutol?
It can cause optic neuritis
They noticed difficulty recognising colours: ethambutol (“eye-thambutol”)
Why does Tb treatent take so long?
There are two Tb populations:
- The replcating bacilli
- The trapped bacilli
What are the different types of Tb resistance?
- Single agent
- Multi-drug resistance
- Extensive drug resistance (rifampicin, isoniazid and quinolone plus an injectable)
What is latent Tb disease?
Symptomless Tb - Tb is in a dormant state
How can it be determined that Tb is active?
- Symptoms present
- Cues through history
- X-rays (can show previous Tb by calcification)
- Culturing is positive
What are two tests for previous Tb exposure?
- Interferon gamma release
- Mantoux (tuberculin test)
Tuberculin is a protein taken from mycobacteria which can prvoke a hypersensitivity reaction so it involves two visits, one for administering the tuberculin, another for measuring the response
What is an alternative test to the tubercuin test that is more sensitive?
IGRA
(Interferon Gamma Release Assay)
Why would latent Tb be treated?
There is a chance the patient may eventually develop symptoms
6 months of rifampicin
or
3 months of rifampicin and isoniazid
Tb often comes hand in hand with which other condition?
HIV
What are some risk factors for pleural infection?
- Diabetes
- Immunosupression from corticosteroids
- Gastro-oesophageal reflux
- Alcoholism
- IV drug user
What is a parapneumonic effusion?
A type of pleural effusion that arises as a result of pneumonia, lung abcess or bronchiectasis
What are the three types of parapneumonic effusion?
- Simple parapneumonic effusion
- Complicated parapneumonic effusion
- Empyema
What is an empyema?
A collection of pus in the pleural space
Large effusions will require _____ _________
Chest drainages
What can be used to break down substances in parapneumonic effusions?
Fibrinolytics and DNAses
What characteristics will a complicated effusion have?
- Ph < 7.2
- Low glucose
- Septations (divided into segments)
- Loculations (containing many cavities)
- +ve on gram stain
what medications should not be given to patients with latent TB
immunosuppression such as TNF alpha inhibitors
