What Is The Most Common Paraneoplastic Syndrome Associated With Small Cell Lung Cancer?

Paraneoplastic syndromes represent a collection of clinical results and effects from a primary malignancy. They are remote effects of cancer that are not caused by the invasion of the tumor or its metastases. In a nutshell, the paraneoplastic syndrome occurs as a result of organ or tissue damage at locations remote from the site of the primary tumor.

What Is The Most Common Paraneoplastic Syndrome Associated With Small Cell Lung Cancer?

Paraneoplastic syndrome is often associated with small cell lung cancer that has the potential to cause disability to a multitude of organ function. The primary organs that are subjected to severe destruction as a result of this syndrome are neurologic, endocrine, dermatologic, rheumatologic and few others.

Some of the common examples of the paraneoplastic syndromes affecting the endocrine and neurologic systems

Endocrine – SIADH syndrome and Ectopic secretion of ACTH

Neurologic- Eaton-Lambert reverses myasthenia syndrome, sub-acute cerebellar degeneration, sub-acute sensory neuropathy and limbic encephalopathy.¹

Physical Findings And Clinical Manifestation Of The Paraneoplastic Syndrome

The clinical tests and diagnosis of paraneoplastic syndromes may characterize the very early or late stages of the disease and apparently, it has no direct connection on the degree or forecasting the syndrome. Nevertheless, medical studies have found that approximately 10% of the patients suffering from lung cancer are prone to this condition. However, it still depends on the type of lung cancer they are affected.

The most common neoplastic syndrome associated with lung cancer is antidiuretic hormone (SIADH, a condition in which the body makes too much antidiuretic hormone) secretion. Based on medical studies, it is found that up to 16 percent of the population is affected with this condition when they reported problems of lung cancer. However, to a greater surprise, seventy percent of paraneoplastic SIADH cases are diagnosed in patients with SCLC.

Physical Examinations

Physical findings in small cell lung cancer (SCLC) are often contingent on the extent of local and distant spread and the organ system involved. Here some of the organ systems are more prone to this condition

Respiratory System- Individuals experience shortness of breath and certain infection in the nasal passage. When the tumor occurs in the central location, patients often develop symptoms of distal atelectasis (a clogged bronchus due to the presence of a tumor that might occur following surgery) and post-obstructive pneumonia (airway obstruction frequently encountered in patients with lung cancer).

Cardiovascular System– Pericardial effusions may be asymptomatic in their initial stages however over a period of time it might result in tamponade. Malignant pericardial effusions are most commonly related to primary small cell lung cancer. Malignant association of the pericardium is often noticed in 1 to 20 percent of examinations in patients with tumor. When this condition is noticed, your healthcare provider will suggest for an echocardiogram which can clearly explain the equalization of pressure in the cardiac chamber.²

Central Nervous System- Brain metastases are the most common problem in a broad collection of cancers, but they are predominantly common among patients with SCLC.

Patients with this condition have raised intracranial pressure to mass lesions surrounding brain edema. Resection and radiation therapy remain standard options for the treatment of this condition. Standard chemotherapy does not cross the blood-brain barrier. So the patients are subjects to fundus photography with angiography to detect small or hidden multifocal tumors³.

The work-up of hyponatremia (low sodium concentration in the blood due to SCLC) can be classified into 3 broader categories based on the patient’s volume status which are majorly the hypovolemia, euvolemia, and hypervolemia. This condition can result in renal and gastrointestinal losses. When attempting to treat a patient’s with paraneoplastic syndrome, the degree of sodium correction and the time it takes to do should be carefully examined because it frequently leads to a serious reaction.

Conclusion

When SIADH patients do not respond to chemotherapy, more aggressive treatment is carried out. Failure to normalize the patient’s sodium level can result in shorter survival.

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What Is The Most Common Paraneoplastic Syndrome Associated With Small Cell Lung Cancer?