الفهرس 
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Abstract
Hepatitis C virus (HCV) is one of the most important infectious agents worldwide and many previous trials have investigated the relation between chronic hepatitis C and the interstitial lung disease (ILD); however, the role of viral load levels is unclear (Kuna, 2019).
ILD is a group of multiple conditions insulting the lung parenchyma and these conditions present with different grades of interstitial inflammation and fibrosis and consequently different clinical, radiological and histopathological manifestations (Bourke, 2006).
chronic HCV infection was suspected for a long time to be involved in the pathogenesis of ILD by inducing chronic inflammation and fibrosis in the lung similar to those induced in the liver and HCV-positive patients without clinical pulmonary symptoms have significantly increased epithelial permeability, suggesting early interstitial lung disease (El Badrawy 2018).
Our study aimed to clarify the association of HCV infection with interstitial pulmonary involvement and to investigate the effect of HCV viremia status and the severity of hepatic affection on lung functions and radiology.
This observational prospective study was conducted on 50 patients with CHC infection from the outpatient clinic of Fayoum chest hospital. They were divided into two groups according to blood viremia assessed by polymerase chain reaction (PCR):
According to HCV-RNA (PCR) result, patients were classified into two groups:
Viremic group; patients who had positive anti-HCV antibodies and positive HCV-RNA (PCR) which indicate current HCV infection.
Degree of viremia (IU/ml) was classified according to viral load of patients into:
o Low viremia = 50-100,000 IU/ml
o Moderate viremia = 100,000 -1,000,000 IU/ml
o High viremia > 1,000,000 IU/ml
Non-viremic group; patients who had positive anti-HCV antibodies with negative HCV-RNA (PCR) which indicate resolved or treated HCV infection.
Both groups were subjected to spirometry, carbon monoxide diffusing capacity (DLCO), high resolution computerized tomography (HRCT) of the chest, arterial blood gases (ABGs), and abdominal ultrasound.
Our results revealed that; there was statistically significant positive correlation between viremic and non-viremic groups regarding to the honeycombing pattern in HRCT being more common in the former group with (P- value 0.006), especially with higher level of viremia. But there was no statistically significant difference between any of other interstitial patterns.
There was a significant correlation between FVC % and the stage of viremia (P 0.006). FVC, was significantly lower in high-viremic and low-viremic groups compared to the non-viremic group. These findings suggested that a high viremia level is associated with reduced lung functions in patients with CHC,
One hundred percent of the patients with honeycombing changes in HRCT had cirrhotic liver changes in abdominal ultrasound with (p-value 0.032). In our study we found a statistically significant difference between honeycombing and Child Pugh classes more in Child class B.
There was no statistically significant difference between the degrees of DLCO% reduction in patients with the different levels of viremia for HCV-PCR (p-value 0.502).
We conclude that; there is a relationship between the chronic infection with HCV and the prevalence of the interstitial lung disease. Moreover there is an association between the honeycombing pattern and higher level of viremia.
Conclusion
As understanding the respiratory effects of HCV which is considered to be a major health problem in Egypt, this might improve our approach in the treatment of respiratory problems complicating HCV.
To do spirometric screening for all patients diagnosed by HCV will not be cost-effective. But identification of the patients with high risk to develop interstitial lung disease is helpful to allow proper selection.
Recommendation
The relation between the higher viremic level detected by PCR-RNA and the fibrotic parenchymal changes and deteriorated respiratory function may raise the importance to identify HCV-infected patients with increasing risk to develop pulmonary complications and to do spirometric lung function as initial assessment as pulmonary fibrosis causes a progressive and devastating loss of pulmonary functions. Therefore, diagnosis of pulmonary involvement in the early stages is of great importance.
Physicians other than hepatologists should be aware about the role of HCV infection and its extrahepatic effects helping the diagnosis of unexplained manifestations as dyspnea and alters pulmonary functions.