Tuberculosis Flashcards

1
Q

Tb is an _________ pathogen

A

Airbourne

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2
Q

What is the difference between Tb infection and disease?

A

Infection means the pathogen cannot be cleared and disease means symptoms are experienced

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3
Q

Where will Tb normally be more prevalent in the lungs?

A

Apices

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4
Q

Why does Tb usually grow preferentially in the lung apices?

A

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

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5
Q

Which type of bacteria is Tb?

A

Bacilli

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6
Q

Why does Tb involve gramuloma formation?

A

Tb can enter alveoli and enter macrophages.

To respond, the body walls off the infected macrophages in a granuloma

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7
Q

In people experiencing Tb symptoms, the body cannot hold the ________ within the _________

A

Infection

Granuloma

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8
Q

How long can a granuloma hold the infection of Tb at bay?

A

It can vary from days to years

A Tb infection can remain “dormant” for many years

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9
Q

Systemic symptoms of Tb include?

A

Weight loss, malaise and night sweats

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10
Q

Respiratory symptoms of Tb include?

A

Cough, haemoptysis, breathlessness and upper zone crackles

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11
Q

If lower lobes are infected with Tb, what does this suggest?

A

The infection occured through blood spread (sepsis)

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12
Q

Tb does not just infect the lungs. What are some other complications of Tb?

A
  • Meningeal Tb
  • GI Tb
  • Spinal Tb
  • Cold abscesses
  • Lymphadeopathy
  • Pericardial - cardiac tamponade
  • Renal
  • Septic arthritis
  • Adrenal - hypoadrenalism
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13
Q

Which type of stan can detect Tb?

A

Ziehl-Neelson

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14
Q

Describe the process by which Tb is identified through staining

A
  • 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
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15
Q

Tb can be identified by staining, how else can it be identified?

A

PCR (polymerase chain reaction)

Culturing

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16
Q

The histology of Tb includes ___________ giant cell _________, _________ necrosis and potentially visible ___________

A

Multinucleate

Granulomas

Caseating

Mycobacteria

17
Q

What is the treatment for Tb?

A

6 month antibiotic course

  • 2 months of
  • Rifampicin
  • Isoniazid
  • Pyrazinamide
  • Ethambutol

Followed by

  • 4 months of
  • Rifampicin
  • Isoniazid
18
Q

What is a side effect of rifampicin?

A

It colours everything orange

(Bodily fluids, urine etc)

Metabolism is sped up in the liver leading to enhanced breakdown of steroid molecules (hormonal contraception) and opiates due to increased production of cytochrome enzymes

19
Q

What is a side effect of ethambutol?

A

It can cause optic neuritis

20
Q

Why does Tb treatent take so long?

A

There are two Tb populations:

  1. The replcating bacilli
  2. The trapped bacilli
21
Q

What are the different types of Tb resistance?

A
  • Single agent
  • Multi-drug resistance
  • Extensive drug resistance (rifampicin, isoniazid and quinolone plus an injectable)
22
Q

What is latent Tb disease?

A

Symptomless Tb - Tb is in a dormant state

23
Q

How can it be determined that Tb is active?

A
  • Symptoms present
  • Cues through history
  • X-rays (can show previous Tb by calcification)
  • Culturing is positive
24
Q

What are two tests for previous Tb exposure?

A
  1. Interferon gamma release
  2. 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

25
Q

What is an alternative test to the tubercuin test that is more sensitive?

A

IGRA

(Interferon Gamma Release Assay)

26
Q

Why would latent Tb be treated?

A

There is a chance the patient may eventually develop symptoms

6 months of rifampicin

or

3 months of rifampicin and isoniazid

27
Q

Tb often comes hand in hand with which other condition?

A

HIV

28
Q

What are some risk factors for pleural infection?

A
  • Diabetes
  • Immunosupression from corticosteroids
  • Gastro-oesophageal reflux
  • Alcoholism
  • IV drug user
29
Q

What is a parapneumonic effusion?

A

A type of pleural effusion that arises as a result of pneumonia, lung abcess or bronchiectasis

30
Q

What are the three types of parapneumonic effusion?

A
  1. Simple parapneumonic effusion
  2. Complicated parapneumonic effusion
  3. Empyema
31
Q

What is an empyema?

A

A collection of pus in the pleural space

32
Q

Large effusions will require _____ _________

A

Chest drainages

33
Q

What can be used to break down substances in parapneumonic effusions?

A

Fibrinolytics and DNAses

34
Q

What characteristics will a complicated effusion have?

A
  • Ph < 7.2
  • Low glucose
  • Septations (divided into segments)
  • Loculations (containing many cavities)
  • +ve on gram stain
35
Q
A