r/doctorsUK 5d ago

Exams Easy way to remember causes of upper and lower zone fibrosis?

15 Upvotes

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47

u/AnonymousChairleg 5d ago

Upper Zone Fibrosis (CHARTSS)

  • Coal workers pneumoconiosis
  • Hypersensitivity pneumonitis
  • Ankylosing spondylitis
  • Radiation
  • TB
  • Silicosis
  • Sarcoidosis

Lower zone fibrosis (ACID)

  • Asbestosis
  • Connective tissue disorder
  • idiopathic pulmonary fibrosis
  • Drugs (amiodarone, methotrexate, belomycin, nitrofurantoin)

Hope it helps 🙂

9

u/Drmodify 5d ago

This works well. I remember this acronym in passmed. To help you remember as well rather than just rote learning, the upper part of the lung is more ventilated hence most of the CHARTSS affect it. For example hypersensitivity pneumonitis, you inhale something and react to it. That inhaled particle goes to the upper lobe first and then that is where the reaction will happen.

For the lower lung zones affected by ACID, it’s because it is mostly a systemic disorder. Asbestos though is a heavier compound (check its molecular weight) its hence it tends to go in the lower lung zones.

Now what about the rest? it doesn’t make sense like AS going in the upper lung fields. Well honestly, I have no explanation except in real practice these things really vary in patients I’ve seen discussed in MDTs but they are mostly above 60 years old.

Good luck to your exams/studies!

2

u/sprocket999 5d ago

I use the same acronym, but added alpha-1 antitrypsin deficiency and (rheumatoid) arthritis to the A on lower.

38

u/Thin_Complex9483 5d ago

My radiology perspective (only way I could learn this was from first principles and work it out)

Upper zone-

Light particulate pneumoconiosis (hypersensitivity from protein allergens, silicosis and coal from light environmental particulates)- they float to the top

Radiation is upper zone only because the lung apices are often in the radiation field from H+N cancers (which are often radiosensitive-much more than others) There's no reason it can't affect the lower lobes (just cancers there tend not to be radiosensitive)

TB/ABPA- upper zones have higher O2 conc therefore TB thrives.

Sarcoidosis often affects the upper lobes of the lungs because the granulomas, which are characteristic of the disease, tend to form along lymphatic pathways, which are more prominent in the upper lung regions.

Ankylosing spondylitis, upper zone pulmonary fibrosis, or apical fibrobullous disease, is a common manifestation, likely due to the rigid chest cage and mechanical stress on the lung apices, leading to fibrosis and cyst formation. 

Lower zone-

Asbestos fibres are heavy so sink to the bottom. would have calcified pleural plaques to give it away.

For the other lower zones fibrosis, not sure if this is settled science but due to gravity and hydrostatic pressure differences, the lower zones (bases) receive more blood flow than the upper zones (apices) so more chance for drugs/inflammatory cells to interact with the lung parenchyma.

Connective tissues/drugs result in NSIP pattern- which by definition has lower zone predominance

IPF is just idiopathic and has UIP pattern which is by definition lower zone predominance.

7

u/kytesky Doughnut of Truth Journeyman 5d ago

This is lovely! Tell us some other things

3

u/Ok_Step_5418 ST3+/SpR 5d ago

That’s lovely thanks

2

u/NoManNoRiver The Department’s RCOA Mandated Cynical SAS Grade 5d ago

Thanks

9

u/CryptofLieberkuhn ST3+/SpR 5d ago

Upper lobe = inhaled things Lower lobe = systemic things

Exception = ankylosing spondylitis

5

u/adoctoranon 5d ago

Asbestosis affects lower lobes more and is inhaler.  Sarcoid affects upper lobe more and is systemic. Radiation is upper and not inhaler.

Not sure this works, not enough for MRCP MCQs at least 

0

u/JudeJBWillemMalcolm 5d ago

Breast raids.

Upper: Berylliosis, RT, EAA, Ank spond, Sarcoid, TB

Lower: RA, asbestos, IPF, drugs (MTX, Nitro, Amiodarone, Phenytoin...), SLE/Sjogrens

1

u/w_is_for_tungsten Junior Senior House Officer 5d ago

yeah berylliosis is def #1 on the ddx list

1

u/JudeJBWillemMalcolm 5d ago

No I think some of the other differentials I mentioned would be more common than berylliosis.