Desquamative interstitial pneumonia J84.9

One of the major forms of "idiopathic interstitial pneumonia" (=major ILPs), which are also referred to as tobacco smoke associated ILPs together with Respiratory bronchiolitis interstitial lung disease (RB-ILD) and Pulmonary Langerhans cell histiocytosis. S.a. Interstitial pneumonia

Unknown

DIP is almost exclusively found in smokers (> 90 %). The age peak lies between 30-50 years. The disease is rare overall and accounts for about 5% to a maximum of 15% of total interstitial pneumonia. Men are affected twice as often as women.

DIP is most likely the same disease as RB-ILD, but with different histology and different CT morphology.

The disease is undoubtedly caused by smoking. However, since not all excessive smokers develop DIP, it can be assumed that the genetic predisposition also plays a role.

Most patients consult their family doctor for persistent coughing in combination with shortness of breath. The symptoms themselves begin insidiously.

The cough is almost always a productive cough (in contrast to all other interstitial pneumonia), since nicotine consumption also causes chronic bronchitis.

Auscultatory fibrosis (inspiratory or late-inspiratory developmental crackling) is found in only about 25% of patients.

Drum flail fingers are found in about 50 % of patients.

Lung function: Here, a restrictive ventilation disturbance, a clear diffusion disturbance with reduction of the TLCO (transfer factor) or DLCO (named as diffusion factor in North America) and hypoxaemia are evident. If a smoker's lung function is primarily a restrictive disorder, further radiological diagnosis must always be carried out.

Any type of tissue removal - sometimes even the BAL - can trigger an acute flare of disease in IPF/UIP. This is not described for the other subgroups. For this reason, however, the indication for biopsy should generally be narrowly defined.

In the case of DIP, however, a BAL is quite helpful. There is a pronounced accumulation of smoking macrophages (accumulation of dust, soot or tar in the macrophages). These are mainly located in the lumen of the alveoli. Neutrophil and eosinophil granulocytes as well as lymphocytes are usually only slightly increased. Fibrotic changes of the interstitium are extremely rare.

It is important to clearly distinguish DIP from common interstitial pneumonia, as DIP responds well to therapy.

• COPD
• Emphysema of the lungs
• other forms of interstitial pneumonia (IPF/UIP, COP, AIP, RB-ILD, LIP)
• Collagenoses
• Pulmonary asbestosis
• exogenous allergic alveolitis
• Sarcoidosis of the lungs

Complications

• respiratory insufficiency
• pulmonary hypertension
• cor pulmonale
• lung carcinoma

The most important measure is to stop nicotine consumption. This alone makes spontaneous remissions possible.

If no remission can be achieved during nicotine withdrawal or if the symptoms are initially very pronounced, treatment with glucocorticoids should be carried out.

Prednisolone: Initial dose 1 mg/kg bw/d, but not more than 50 mg/d. After 4 weeks halve the dose, after another 4 weeks halve it again.

The prognosis of DIP is slightly worse than that of RB-ILD.

However, spontaneous remissions are possible after giving up smoking. The 10-year survival rate is about 70 %. However, late relapses can also occur (renewed nicotine abuse?).

The previously suspected transition of a DIP to an IPF does not occur.

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