LUNG CANCER

Lung Cancer

Lung Cancer

Introduction

The basic pathological processes in sickle cell disease are chronic anaemia and blood vessel occlusion leading to acute and chronic organ damage. Repetitive cycles of sickling and polymerization lead to membrane rigidity, and irreversible sickle cells are eventually formed. These permanently damaged erythrocytes are then cleared by the reticuloendothelial system. As the red blood cells are removed, their concentration falls, reducing the rate of destruction until it just balances the maximal rate of red blood cell production by the marrow. Bone marrow aspirate will show erythroid hyperplasia and the blood film will show sickle-shaped red blood cells and polychromasia.

Painful sickle cell crisis

Background

The most common manifestation of SCD is the acute painful crisis which occurs secondary to vaso-occlusion. These painful crises can be precipitated by infection, stress, dehydration and cold damp conditions. There is an increased risk of painful crisis during pregnancy, especially in the latter half of pregnancy and the puerperium, and they may even occur in women who have previously had very few episodes of sickle pain.

Acute chest syndrome

This life-threatening complication presents with cough, chest pain, dyspnoea, fever, worsening anaemia, leucocytosis, audible crackles and/or bronchial breathing on examination, and a florid infiltrate on the chest X-ray. The patient may need assisted or mechanical ventilation. This is among the most common causes of maternal death. The syndrome arises due to sickling in the lungs, possibly combined with infection. Although there are thought to be many causes, the underlying features are not totally understood. Treatment is often inadequate, although early detection and treatment may reduce the severity and prevent death. Dramatic improvements have been noted following exchange blood transfusion, therapeutic subcutaneous doses of heparin and antimicrobial agents.

Endocrine and metabolic changes

It is currently thought that iron overload is the main underlying cause of endocrine dysfunction in patients with SCD. Increased numbers of transfusions have been associated with greater risk of endocrine organ failure. Growth failure and delayed pubertal development, gonadal failure, diabetes and carbohydrate intolerance and primary hypothyroidism have been documented.  Generally, treatment consists of replacement of particular hormones and improvement of nutritional status. An unanswered question is whether patients with SCD are prone to endocrine pathology in the absence of iron overload due to crises in the glands. Future work may allude to this.

Other complications

In patients with SCD splenic infarction has usually occurred by 5-6 years of age, leading to a lifelong increased risk of infection, especially due to encapsulated organisms such as Streptococcus pneumoniae and Haemophilus influenzae. Occasionally, splenomegaly or splenic sequestration, which is associated with profound anaemia, can occur in adults when splenic autoinfarction has not taken place.

Antenatal screening

The antenatal screening programme aims to identify women with haemoglobinopathies who need specialist care in pregnancy, and to offer couples who are carriers and at risk of passing on the disorders the option of fetal screening in the first (or second) trimester. Thalassaemia screening using routine blood indices is formally offered to all women in England and Wales.

The policy for implementing screening for sickle cell ...