Progressive Massive Fibrosis

Progressive massive fibrosis is a lung disease that is predominantly reported in people who work in mines. Hence it is also called Coal worker's Pneumoconiosis. Fibrosis is a nodular formation in different regions of the body. Often lungs are the most vulnerable. This is because of aerosol initiation, which has a faster chance of nodule formation causing tissue damage.

Clinical Manifestations

Most conditions associated with massive fibrosis are coherent to silicosis and pneumoconiosis. Lesions are caused due to tissue necrosis, which leads to hardening of the tissue forming nodular structures. In case of progressive fibrosis, massive scars are noticed because of dense agglomeration of the thickened nodules. These nodules predominantly appear in the upper lobes causing respiratory difficulties.

The onset of this disease is triggered by macrophage proliferation in the respective regions. The macrophages engulf the inhaled silicon particles causing the production of interleukin -I which facilitates the chemical mediation for tissue necrosis. Silica is commonly found in these necrotic nodules. The adverse effects of these silica particles are the onset of Pulmonary Alveolar Proteinosis (PAP) causing the accumulation of large particles, which can be noticed as spaces on radiological examination. Along with the affected upper lobe, the interstitial zones of the lower lobe are also obstructed and bronchial regions are damaged with the infiltration of the nodules. Honeycomb lung or asbestos bodies are common references for progressive massive fibrosis as both these conditions have giant cells upon pathological examination. Bronchogenic carcinoma and mesothelioma are the associated adverse conditions of progressive massive fibrosis.

The evaluation of patients suffering progressive massive fibrosis includes the understanding of the type of chemical or particle inhaled as it enables the physicians to rule out diagnostic errors. In cases such as pleural plaques, calcified regions of the lungs are noticed which is another cause of asbestosis. The lower region of the lungs are predominantly affected. In case of interstitial fibrosis, the bronchus and alveoli are affected with characteristic nodules of the upper and mid region. The evaluation is based on the type of chemical and the respective interleukins it releases. Most patients associated with these conditions are miners, shipyard workers, automobile mechanics and petrochemical employees.

Diagnosis and Treatment

Most diagnostic evaluations are radiological in origin as the MRI provides detailed description about the zones of the fibrosis and the size of each nodule. Histopathological analysis studies the intensity of the necrosis, giant cell presence and the macrophagic proliferation patterns. The treatment pattern is based on symptomatic analysis. Since the condition includes both lower and upper lobes, any associated mycobacterial infection has to be treated. Oxygen is given as a critical care measure in patients with hypoxemia. Surgical interventions are applicable in case of intense and irreversible tissue necrosis. Patients with progressive massive fibrosis are advised to quit smoking if as it causes intense damage.

Hypoxia

The body needs a specific amount of Oxygen to function normally and when this amount is lowered the body experiences hypoxia. Hypoxia literally means lack of oxygen for effective ventilation.

Hypoxemia refers to a state of abnormally low level of Oxygen in the blood.
Anoxia refers to the condition of absence of Oxygen supply to an organ or tissue
Anoxemia refers to the condition where the blood stream contains below normal amount of Oxygen.

Hypoxia is primarily classified into:

Generalized hypoxia: affects the entire body, may occur in normal healthy people when they scale high altitudes.
Local hypoxia: affects one particular region of the body.

When the level of oxygen in the blood reduces, it leads to the condition. People suffering from conditions like ischemia or blockage/constriction of blood vessels may suffer from hypoxia. In general when people travel from low to high altitudes, they may face this problem as the oxygen level depletes with altitude.

Hypoxia causes

Any condition wherein the body is deprived of oxygen can lead to hypoxia. Major causes that lead to the condition include:

• Severe head trauma
  
• Ischemia
  
• Asthma Severe Asthma can result in hypoxia and in Hypercarbia or Hypercapnia (elevated levels of Carbon dioxide CO₂ in blood)
  
• Pulmonary embolism
  
• Carbon monoxide poisoning
  
• Chronic alveolar hypo ventilation
  
• Shock can result in cellular hypoxia in the extremities
  
• Suffocation
  
• Choking
  
• High altitude climbing
  
• Inadequate ventilation

Types of hypoxia

Hypemic hypoxia: Obstruction in the ability of the blood to deliver oxygen, caused by carbon monoxide poisoning.

Anemic Anoxia: Occurs due to a decrease in the hemoglobin or RBC making it too little for the blood to carry oxygen. Anemia may be the result of iron deficiency, hemorrhage or shortened life span of RBC owing to an autoimmune disease.

Histotoxic: When the required amount of oxygen reaches the body part, however it does not utilize it because of its reduced ability, it is called as histotoxic hypoxia. Cyanide poisoning, for example, incapacitates a cellular enzyme essential for oxygen utilization. Other causes include: Alcohol, narcotics, acetone, formaldehyde and some anesthetic agents.

Hypoxic: Also called as Hypoxemic Anoxia: When the body does not receive the required amount of oxygen it leads to low partial pressure of oxygen in the blood thus leading to hypoxic hypoxia. The oxygen pressure of the blood which gets supplied to other body tissues is too low to push and flood the hemoglobin with oxygen. High altitude has lower density of air and lower pressure of oxygen than at sea level. Altitude Sickness occurs because the partial pressure of oxygen decreases with altitude. Hypoxemia is the direct result of lower oxygen in the high altitude which translates to lower level oxygen in the blood.

Stagnant: Obstruction of blood that carries oxygen. It can be due to exposure to cold, diseases which stifle blood circulation to the extremities or ergot poisoning.

Pulse Oximetry, a non invasive test is useful to diagnose Hypoxia. A blood test like serum lactate test can show elevated levels of lactic acid - the result of starvation of oxygen in tissues. The normal level of lactic acid is less than 2 mmol/L. However an increase in lactic acid alone does not indicate hypoxia and some form of Anoxia does not increase the lactic acid concentration. Symptoms may be dangerous on the onset and may include the following:

Generalized hypoxia

• Tachypnea or rapid breathing
  
• Severe headache
  
• Dizziness
  
• Nausea
  
• Tingling sensation
  
• Visual impairment
  
• Shortness of breath
  
• Bluish tint on the lips or on finger tips
  
• Coma
  
• Seizures
  
• Euphoria
  
• Mental fatigue
  
• Muscle fatigue

• Hot and cold flashes
  
• Discoloration of skin
  
• Pain in the area of hypoxia
  
• Severe hypoxia may cause gangrene

Hypoxia Treatment

Some types of Hypoxia cannot be prevented. Treatment depends on the severity of the condition and the appearance of the clinical symptoms. Treatment may include the following:

• Restoration of the tissue oxygen by supplementing the air supply with 100 % oxygen.
  
• Blood pressure and heart rate should be brought back to normal.
  
• In case of high altitudes, the person should be given sufficient rest and should not climb any further.
  
• Hypoxemic hypoxia patients can be put on blood transfusion.
  
• Proper medication and timely treatment can help save the life.

Oximeter

An Oximeter helps measure the oxygen level (or oxygen saturation) in the blood. It is useful in measuring the efficiency of oxygen delivery to the peripheral tissues such as the finger, nose and earlobes. A pulse Oximeter helps monitor the blood oxygen levels of patients suffering pulmonary or cardiac diseases such as congestive heart failure (CHF) and chronic obstructive pulmonary disease (COPD). The Oximeter works on the pulsating feature of the blood flow in the arteries and light absorption capacity of hemoglobin to indicate the body's oxygenation status in a Photoplethysmogram (Volumetric measurement obtained through an optical device).

The Pulse Oximeter beams red and infrared light into the capillaries inside the finger. While oxygenated blood absorbs light at 660nm (red light), the 940nm (infra-red) is absorbed preferentially by deoxygenated hemoglobin in the blood. The relative absorption of light is measured by light collecting sensors. This information is then processed to arrive at the oxygen saturation level of the blood. The pulse Oximeter also displays the pulse rate. Factors that affect the accuracy of the pulse Oximeter readings are weak pulse, hypoperfusion (poor blood circulation), vasoconstriction, cold hands, acrylic nails and high altitude.

The oxygen saturation (SpO₂) is measured as a percentage of full capacity. SpO₂ should ideally be between 96% to 99%. When the SpO₂ falls below 92%, it is suggestive of Hypoxemia or Hypoxia. The patient might need oxygen supplementation.