UNCONTROLLED HIV DISEASE

1. INFECTIONS

Infections of respiratory tract are the most frequent cause of infection in the HIV patient with any CD4 count

BACTERIAL NEUMONIA

It is the most common cause of lung infection in the seropositive patient. Imaging findings are similar to inmunocompetent patients; single or multifocal áreas of consolidation .

The most common cause is streptococus pneumoniae, as in immunocompetent (fig 1) 

PNEUMOCYSTIS JIROVECII PNEUMONIA ( PCP) 

If CD4 cell count falls below 200 cells/mm³ , increase the risk develops pneumocystis jirovecii pneumonia 

CT findings. Ground -glass opacity indicates cells and fluid within the alveoli , is the most common and highly suspicious for PCP. It has variable distribution , peripherical sparing , patchy and diffuse 

Other  findings are ; lung cysts secondary to tissue necrosis  

(upper lobe predominance). May lead to pneumothorax and pneumomediastinum (fig2) . Interlobular septal thickening , crazy paviment pattern , & diffuse consolidation  

Chronic PCP shows pulmonary architectural distortion 

TUBERCULOSIS & NONTUBERCULOUS MYCOBACTERIAL 

Patients with AIDS have a greater risk of developing tuberculosis,  associated with higher mortality.

Radiological manifestations depend on the degree of immunity.

Above 200 cells/ mm³ CD4  count  ,  imaging findings are those of tuberculous reactivation in the normal host: single or multiple  1-3 cm nodules, consolidation, cavitation involving upper lobes , tree-in-bud pattern  due to endobronchial spread.( fig 3 )    

Between 50 and 200 CD4 cells/mm³ count, the findings usually correspond to those of the primary infection with a miliary pattern, areas of consolidation, pleural effusion and hypodense center lymph node enlargement. ( fig4)

Below 50 cells/ mm3, the radiological manifestation can be anyone, are not specific; consolidation or ground glasss opacities 

CYTOMEGALOVIRUS PNEUMONIA 

CMV is commonly detected on BA lavage in AIDS patients , but in small number of patients can result in disseminated infection (fig 5) and pneumonia ( fig 6)

It use to be common below 100 CD4 cells/ mm³ count. CT findings in neumonía are heterogeneus ; consolidation, ground glass opacities , small nodules in random distribution . In fact, it is difficult   differentiate from PCP neumonia  

PULMONARY CRYPTOCOCCOSIS 

Cryptococcosis  is a systemic micosis caused by  C. neoformans and C.gattii. Below 200 CD4 cells/ mm³ count may appear.  

The most cammon manifestation is multiple nodules or masses , being the cavitation in masses or larger nodules( 10-30 mm) very  frequently in inmunocompromised patients ( fig 7) . 

HISTOPLASMOSIS AND COCCIDIOMICOSIS  

AIDS patients , previously exposed to these  fungal spores  , are at greater risk of having a disseminated involvement.

CT findings consist of a miliary pattern (hematogenous dissemination )  or diffuse air-space consolidation  

2. MALIGNANCIES

The risk of Kaposi’s sarcoma and non-Hodgkin’s lymphoma (NHL) is significantly greater among HIV- infected persons. Therefore these types of cancer are included like AIDS-defining condition 

KAPOSI´S SARCOMA (AIDS-KS)

Low-grade mesenchymal neoplasm of blood and lymphatic vessels,caused by HHV-8 . Primarly affecting skin , but later cause disseminated disease.

Most patients have less tan 200 CD4 cells/ mm³ count, 

CT and chest X ray findings are peribronchovascular-central predominance of nodules and pulmonary opacities with halo sign , flame-shaped lesions. Interlobular septal thickening and pleural effusion are others findings ( fig 8)

DIFFUSE LARGE B CELL LYMPHOMA 

The most frequent AIDS- condition lymphoma , presents at advanced stage , almost always with B symtoms and extranodal disease, mainly in severely inmunosuppressed patients.

Associated oncogenic EBV 90 % .

Low CD4 count , worse prognosis.

3. HIV- ASSOCIATED CARDIOMYOPATHY

Cardiomyopathy has different etiologies :

· Myocarditis 

· Tuberculous myopericarditis ( 90% of pericardial effusions )

· Direct HIV 

· Toxicity, 

· Opportunistic infections 

· Micronutrient deficiency

One third of cardiac deaths are due dilated cardiomyopathy ,with sistolic disfunction ( fig 9)

CONTROLLED HIV DISEASE 

1. INFECTIONS

The incidence of bacterial pneumonia is the same in correctly treated patients as in other immunocompetent patients. Opportunistic infections appears in case of a decrease in CD4 .( fig 10)

2. Non -AIDS MALIGNANCIES

Persons with HIV infection develop non– AIDS-related types of cancer more frequently than the general population 

LUNG CANCER

It is the most common and the leading cause of cancer -related mortality among HIV infected. Some studies consider VIH was an independent risk factor for lung cancer , but in fact almost all patient use to be smoker also , so is unclear.

Appears in young people and advanced stages. Same radiological imaging ( fig 11 y 12) 

HODGKIN LYMPHOMA 

Frequently with unfavorable features : advanced-stage, extranodal disease and bone marrow involvement.

EBV associated in 90% cases. Low CD4 count is an independent adverse prognostic factor. But improvement from severe to moderate CD4 count on ART patients increase incidence (fig13)

Prognosis is quite good before ART era, with high survival rates.

CT findings are lymphadenopathy , tipically in mediastinum and hepatosplenomegaly

MULTICENTRIC CASTLEMAN DISEASE 

It is an aggressive B-cell lymphoproliferative disorder , icreased in HIV patients and may turn into NHL. Strongly associated HHV8 

(100 %) . Usually with clinical B symptoms weakness and malaise It is more prevalent in the ART era. CT shows lymph nodes and spleen enlargement ( fig 14 ) 

PRIMARY EFFUSION LYMPHOMA

Rare B-lymphoma characterized by effusions in pleura, pericardium and peritoneum in advanced HIV disease. HHV8 and EBV are associated oncogenic virus, almost 100% of cases 

3. INMUNE RECONSTITUTION INFLAMMATORY SYNDROME (IRIS)

It is a paradoxical deterioration in clinical status attributed to the initiation of ART, while the CD4 count increase , and is a diagnosis of exclusion.

IRIS has been described in association with a wide range of opportunistic infections, autoimmune diseases and malignancies.

Mycobacteria & fungal infection , herpes viruses & other virus , Kaposi’s sarcoma & lymphoma, and weirder sarcoidosis

TB-IRIS followed by MAC-IRIS are most common of IRIS worldwide and use to be unmasks infections . CT findings are usually lymphadenopaty (central necrosis) and lung miliary pattern ( figs 15 , 16 )

4. HIV- ASSOCIATED CARDIOMYOPATHY & PULMONARY HYPERTENSION

Cardiomyopathy are use to be due to autoimmunity, inflammation, and ART toxicity. 

Abnormalities are because diastolic dysfunction , but normally are subclinical 

Pulmonary Hypertension has higher prevalence given long life expectancy of patients . Most of cases , cause is HIV itself , but other causes like chronic pulmonay emboli or COPD must exclude 

Imaging findings are dilatation of the main pulmonary artery and right chambers. ( figs 17 ,18) 

5. COPD

Some studies consider HIV is a risk factor itself for development emphysema , but the incidence of smokers is higher in infected patients, and is a common illness ( fig 19 )

 6. Lymphocytic Interstitial Pneumonia ,LIP

It can appears at any CD4 count , but usually when is normal. Children are affected more tan adults.

EBV is associated . CT findings are diffuse ground glass opacities with centrinodular nodules and thin-walled cysts ( fig 20 )