Sickle cell anemia: Causes, symptoms, diagnosis and treatments.
Definition
Sickle cell anemia, or sickle cell disease (SCD), is a genetic
disease of the red blood cells (RBCs). Normally, RBCs are shaped like
discs, which give them the flexibility to travel through even the
smallest blood vessels. However, with this disease, the RBC’s have an
abnormal crescent shape resembling a sickle. This makes them sticky and
rigid and prone to getting trapped in small vessels, which blocks blood
from reaching different parts of the body. This can cause pain and
tissue damage.
History
- The symptoms related to sickle cell crises were known by various
names in Africa, long before they were recognized in the western
hemisphere. Symptoms of sickle cell anemia could be tracked back to year
1670 in one Ghanian family.
- It was in 1910 when James Herrick observed, “peculiar elongated
sickle shaped RBCs” in the blood of an anemic black medical student, and
then the scientific community came to know about it.
- It was the discovery of Emmel in 1917 of the sickling phenomenon, in
vitro, in the members of a family which first suggested the genetic
basis for sickling. So it was discovered to be an inheritable condition.
Later on it was explained that the sickling phenomenon, in vitro, was
due to deprivation of oxygen.
- Both Huck and Sydenstricker, who did the detailed analysis of the
pedigrees of Huck’s patients, concluded that the sickle cell phenomenon
was inherited as a Mendelian autosomal recessive characteristic.
Types
There are several types of sickle cell disease. The most common are:
- Sickle Cell Anemia (SS),
- Sickle Hemoglobin-C Disease (SC),
- Sickle Beta-Plus Thalassemia,
- Sickle Hemoglobin-D Disease and
- Sickle Beta-Zero Thalassemia.
Sickle Cell Anemia (SS): When a child inherits one
substitution beta globin genes (the sickle cell gene) from each parents,
the child has Sickle Cell Anemia (SS).
Sickle Hemoglobin- C Disease (SC): Individuals with
Sickle Hemoglobin-C Disease (SC) have a slightly different substitution
in their beta globin genes that produces both hemoglobin C and
hemoglobin S.
Sickle Beta-Plus Thalassemia: Sickle beta-plus
thalassemia affects beta globin gene production. The size of the red
blood cell is reduced because less beta protein is made. If inherited
with the Hb S gene, you will have haemoglobin S beta thalassemia.
Symptoms are not as severe.
Sickle Hemoglobin-D Disease: Through research,
hemoglobin D, which is a different substitution of the beta globin gene,
has been found to interact with the sickle hemoglobin gene.
Sickle Hemoglobin-O Disease: Hemoglobin O, another type of substitution in the beta globin gene, also interacts with sickle hemoglobin.
Causes
The basic cause of sickle cell anemia involves hemoglobin, a
component of the red cells in the blood. The hemoglobin molecules in
each red blood cell carry oxygen from the lungs to organs and tissues
and then bring back carbon dioxide for removal by the lungs. In sickle
cell anemia, this process is disrupted. After the hemoglobin molecules
give up their oxygen, some of them may cluster together and form long,
rod-like structures that become stiff and assume a sickle shape and gene
mutation is also leads to inherited one gene for hemoglobin S from each
parent.
Symptoms
- Yellow eyes
- Painful swelling of hands and feet
- Frequent pain episodes
- Stunted growth
- Stroke
- Anemia (looking pale)
- Dark urine
Diagnosis
- A blood test can check for hemoglobin S- the defective form of hemoglobin that underlies sickle cell anemia.
- Sickle cell disease can be diagnosed in an unborn baby by sampling
some of the fluid surrounding the baby in the mother’s womb (amniotic
fluid) to look for the sickle cell gene.
- DNA analysis: This test is used to investigate alterations and
mutations in the genes that produce hemoglobin components. It may be
performed to determine whether someone has one or two copies of the Hb S
mutation or has two different mutations in hemoglobin genes (e.g., Hb S
and Hb C).
Treatment and medications
- Rehydration with intravenous fluids helps red blood cells return to a
normal state. The red blood cells are more likely to deform and assume
the sickle shape if you’re dehydration.
- Treating underlying or associated infections is an important part of
managing the crisis, as the stress of an infection can result in a
sickle cell crisis. An infection may also result as a complication of a
crisis.
- Blood transfusions improve transport of oxygen and nutrients as
needed. Packed red cells are removed from donated blood and given to
patients.
- Supplemental oxygen is given through a mask. It makes breathing easier and improves oxygen levels in the blood.
- Pain medication like morphine is used to relieve the pain during a sickle crisis.
- Hydroxyurea (Droxia, Hydrea) helps to increase production of fetal hemoglobin. It may reduce the number of blood transfusions.
- Immunizations can help prevent infections. Patients tend to have lower immunity.
- Bone marrow transplant has been used to treat sickle cell anemia.
Prevention
- Drinking plenty of water (hydration).
- Avoiding extremely hot or cold temperatures.
- Avoiding places or situations with low oxygen, such as high altitudes, military boot camp, or strenuous athletic training.
- Getting plenty of rest and taking frequent breaks during exercise.
- Taking the medicine Hydroxyurea. People taking hydroxyurea must be
monitored regularly by a doctor to ensure the right dose is given for
the best effect.
Disease (MND): Types, risk factors and preventions.
Definition
Motor neurone disease (MND) is a neurodegenerative disease that
causes rapidly progressive muscle weakness and eventually results in
paralysis. Specifically, this disease affects nerve cells (motor
neurons) that control the muscles that enable to move, speak, breathe
and swallow. MND is also known as Amyotrophic Lateral Sclerosis (ALS) or
Lou Gehrig’s disease.
History
Augustus Waller an English scientist described the appearance of
shriveled nerve fibers in 1850. In 1869, the connection between the
symptoms and the underlying neurological problems were first described
by Jean-Martin Charcot, who initially introduced the term amyotrophic
lateral sclerosis. Amyotrophic comes from the Greek word amyotrophia. a
means “no”, myo refers to “muscle”, and trophia means “nourishment”;
amyotrophia therefore means “no muscle nourishment,” which describes the
characteristic atrophy of the sufferer’s disused muscle tissue.
Types
MND can be sub-divided into different clinical forms although there
is considerable overlap between the different types. The organs
connected with Upper motor neuron (UMN) and Lower motor neuron (LMN) is
represented in figure 2.
“Classical” spinal onset MND
- The upper and lower motor neurons of the arms and legs are damaged leading to weakness and stiffness
- The life expectancy is usually 3 and 5 years
- More common in men
Progressive bulbar palsy (PBP)
The upper and lower motor neurons supplying muscles of speech and
swallowing are affected first, leading to difficulties with chewing,
swallowing and speech Progressive bulbar palsy (PBP)
- Symptoms are like slurred speech and difficulty with fluids
- The life expectancy is lower than spinal onset disease
Progressive Muscular Atrophy (PMA)
- Only lower motor neurons are affected. This leads to weakness and wasting of muscles, without stiffness
- This form is rare and is more common in men
- The life expectancy is longer than for “classical” MND
Primary Lateral Sclerosis
- The form affects only upper motor neurons. Onset is with stiffness
in the legs, with progression to involve the arms, and speech and
swallowing
- Diagnosis is difficult, and requires observation for at least 3 years
- The life expectancy is 10-15 years
Sporadic and Familial MND
- Sporadic MND: Sporadic MND is the term used for cases of the disease
where there is no family history. If anyone is not aware of family
members who has MND then chances are it is sporadic
- Familial MND: It is the term used when more than one member of a
family has been diagnosed with the disease. This may be within the same
generation or passed from one generation to some members of the next
Risk factors
- Environmental factors such as toxins associated with water and air
- Enormous stress on mind
- Unhygienic health conditions
Causes
- Gene mutations
- Excitotoxicity: Excess glutamate in the key areas of brain and spinal cord
- Excess Oxidation
- Deficient neuronal blood supply
Symptoms
- Loss of grip in hand and arm
- Feet and leg trips easily while walking
- Change in voice and slurred speech due to loss of neuronal signal to bulbar muscle
- Muscle cramp and twitching of weakened muscle
- Jerking of arms and legs when it is at rest
Diagnosis and Test
- Magnetic resonance imaging (MRI) scan
- Electromyography (EMG) – a test where needles are used to measure the electrical activity in muscles
- Blood investigation and lumbar puncture
- A muscle biopsy is occasionally performed
- Nerve conduction test – which is similar to an EMF, except the speed
that nerves are able to conduct an electrical signal is measured.
Treatment and Medication
- Riluzole- It is an anti-glutamate agent, which inhibits the amount of glutamate released into the brain
- Medications such as Phenytoin and carbamazepine are used to treat muscle cramp
- Complementary therapies such as acupuncture, reflexology, massage and aromatherapy
Prevention
- Environmental factors are suspected to cause non-inherited motor
neuron disease, however this is still an often debated topic, as
researches still can’t provide strong evidences
- The best chance to prevent this condition is by removing as much as
toxins in living environment as possible, improving hygiene and adopting
a healthy lifestyle
