Functional class is one way doctors assess the severity of PAH symptoms. The World Health Organization (WHO) created a system of 4 functional classes (FC) for patients with PAH. Class I means fewer symptoms and less restriction of activity. Class I symptoms are considered the least severe, and Class IV symptoms the most severe. Here are some basic criteria for each FC:
No symptoms with ordinary physical activity.
Symptoms with Ordinary Activity. Slight Limitation of Activity.
Symptoms with Less than ordinary activity. Marked limitation of activity.
Symptoms with any activity or event at rest.
Idiopathic pulmonary fibrosis (IPF) is a scarring disease of the lungs of an unknown (idiopathic) cause and is the most common of the idiopathic interstitial pneumonias. IPF is characterized by the progressive loss of the ability of the lungs to absorb oxygen, ultimately resulting in respiratory failure and death. While the precise causes of IPF remain unknown, IPF rarely presents before age 50 and can be associated with cigarette smoking and certain genetic dispositions. In addition, some evidence suggests that gastroesophageal reflux (acid reflux, or heartburn), certain viral infections, air pollution, and some exposures in the workplace may be risk factors for IPF. IPF is estimated to affect approximately 100,000 patients in the United States and the median survival of patients with IPF ranges from 2 to 3 years.
Neuroblastoma is a rare cancer that primarily affects children. Neuroblastoma occurs when immature nerve cells (also called neuroblasts) fail to normally develop into mature nerve cells. These immature nerve cells then multiply, leading to the growth of a cancerous mass of cells (tumor). Neuroblastoma tumors can originate anywhere in the body but are often found in the abdomen or belly and usually involve the adrenal glands, which sit on top of the kidney. The chest, neck, hips, bone marrow, and pelvis are other sites that are commonly affected by neuroblastoma. Once diagnosed, neuroblastoma can be further classified according to the level of risk (i.e., low, intermediate or high-risk) it may pose to the patient. Risk classification is based on factors known to affect prognosis (i.e., chance of recovery) and the risk of the neuroblastoma returning after treatment (i.e., relapse). The factors that impact risk classification include, age of diagnosis, stage of disease, and other characteristics of the tumor.
WHO Group 1 pulmonary hypertension is also known as pulmonary arterial hypertension (PAH) and is distinguished by high blood pressure that specifically occurs in the vessels that supply the lungs. This is distinct from more generalized hypertension which is characterized by high blood pressure in vessels throughout the body. In PAH, the blood vessels in the lung stiffen and become narrower, which increases the pressure in the arteries and causes the heart to pump harder in order to pass blood through them. Over time, the added stress from heightened blood pressure in the lungs can cause the heart to weaken. Patients with PAH commonly experience symptoms such as shortness of breath, fatigue, chest pain, dizziness and/or fainting. These patients can also experience difficulties in completing normal activities such as climbing stairs.