5-6-Cystic pattern

1-Multiple thin wall lesions containing air with size 1 cm or more.

2-Causes:

We can use mnemonic HELP CT where

-H is histiocytosis( sizable cysts + nodules at periphery of cysts +spare lower zones ).

-E is emphysema( centrilobular emphysema).

I can know that this is emphysema and not any other types of cystic pattern by presence of para septal type of emphysema.

-L  is lymphangiomyomatosis( only in reproductive female + all lung +no nodules + small and numerous cysts about 2.5 cm ).

Lymphangiomyomatosis with pneumothorax

-L  is lymphocytic interstitial pneumonia( fever + cough + expectoration ).

-P  is Pneumocystis carinii.

-C is cystic bronchiectasis(can be defined by presence of traction bronchi). 

-T is Tuberous sclerosis(pulmonary cysts are similar to that of lymphangiomyomatosis(differentiated by clinical picture).

3-Cystic pattern cannot be seen in plain chest X-ray but honey combing could be noted due to thickness of its wall.

4-One of the cyst can explore causing pneumothorax.

5-Pneumothorax are more common in lymphangiomyomatosis which could cause chylothorax (which cannot be seen in other causes of cystic pattern).

6-Emphysema:

-X-ray findings:

*Prominent hilar vascular shadows.

*Peripheral attenuation of the peripheral vascular markings.

*Increased retrosternal and retrocardiac spaces seen in the lateral film.

*Low flat diaphragm and elongated cardiac shadow.

*Emphysematous bullae.

-CT findings:

*Two types which are centrilobular and paraseptal emphysema.

*Centrilobular appears as multiple cysts present in the center of the lung.

*Paraseptal emphysema is the most common type of emphysema and appears as multiple cysts at the periphery of the lung.

*D.D.between emphysema and lymphangiomyomatosis.

Lymphangiomyomatosis occurs only in females and does not shows cysts at the periphery of the lung.

7-Bullous lung disease(Vanishing lung syndrome):

-Uncommon cause of respiratory distress in males.

-Patients have history of significant cigarette smoking.

-Multiple large bullae impair the pulmonary mechanics.