Wednesday, January 18, 2012

Alcohol vs. Brain



Alcohol vs. Brain
Author: Dr. Krishna N. Sharma
Email: dr.krisharma@gmail.com
Cont: +91-9320699167
 
  As the alcohol affects on the body as a whole and disturbs the function of various body systems, the nervous system is not untouched from it’s grip. The alcohol starts it’s affection to the nervous system from the very first intake of this over the safety limit.

     Long term consumption of the alcohol produces a list of disorders, but apart from the disorders of other body systems and even rare disorders of the nervous system, we shall discuss on the alcohologenic disorders which are frequently seen in the Indian community.
The disorders we are going to discuss here are:
Alcoholic Cerebellar Degeneration

  • Alcohol Myopathy
  • Central Pontine Myelinolysis
  • Corpus Callosum Demyelination
  • Alcoholic Dementia
  • Alcoholic Cerebellar Degeneration

Alcoholic Cerebellar Degeneration
   
     This is a disorder involving a part of the brain called cerebellum. As the cerebellum is responsible for the balance, coordination and the muscle tone, the main victim of this is none but the mobility.

     It is probably the commonest cause of the acquired ataxia (difficulty in walking). It may be seen with two more backgrounds i.e. nutritional deficiency (mainly thiamine) and electrolyte disturbance on the cerebellum which are also capable to produce the cerebellar degeneration. Since the alcohol consumption is maximum in the male so the males are predominantly affected.

     In this the upper limbs are spared and the lower limbs are involved. The main features of this disorder are ataxia (difficulty in walking), nystagmus (bouncing movement of the eyes), dysdiadichokinesia (failure to perform a rapid alternate movement), disturbance of speech, titubation (rhythmic nodding tremor of the head) and involuntary movements.

     The way of progression of the disorder varies. It may evolve subacutely or may evolve chronically and slowly progress many years. Sometimes it may evolve rapidly and reverse in case of alcohol withdrawal and improved nutrition.

     The C.S.F. (Cerebro-Spinal Fluid: a fluid present in and around the brain and spinal cord) examination shows everything normal so it is diagnosed by finding the patient’s long history of alcohol abuse, elevation of enzymes- ã GT in the Liver Function Test, Macrocytosis in peripheral blood film, and cerebellar vermal atrophy in the CT Scan and MRI.

Alcohol Myopathy

    A long term heavy drinking may damage the muscles. An elevated creatine phosphokinase is seen in alcoholic people following an acute ingestion. The causes of this disorder are uncertain but various suggestions like potassium depletion, mitochondrial disturbances etc. are suggested.

There are two types of the alcohol myopathies:

  1. Acute Necrotizing Myopathy
  2. Chronic Myopathy

Acute Necrotizing Myopathy:
     The symptoms of this myopathy occur after too much drinking and start in just hours or days. The major symptom of this disorder is the muscular pain, swelling and tenderness (pain on palpating the muscle mainly the calf muscles) due to the degeneration of the muscles. It is not necessary that the affection is in the symmetrical limbs.

     These symptoms coexist with the symptoms of the alcohol withdrawal like delirium. The elevated level of the K+ in the blood serum causes the heart to beat arhythmically known as the cardiac arrhythmia. The symptoms may take several weeks to months to be normalized.


     The problem does not finish here. It may cause other disorders in its subsequence. A substance myoglobin is released from the damaged muscle tissue which is further excreted from the urine called myoglobinuria. This may cause the kidney failure (renal failure).

Chronic Myopathy:
     It takes time to progress. It is a painless disorder which is characterized by the muscle weakness preferably closed to the trunk known as proximal muscles. Sometimes it is associated with the degeneration of the heart muscles which is known as cardiomyopathy. In biopsy the muscles show type 2 muscle atrophy. As a whole it causes instability followed by the muscle weakness.


Central Pontine Myelinolysis

     It is a life threatening disorder of the brain in which an important part of the brain called Pones degenerates. In this disorder, an essential sheath of the brain cells (neurons) called myelin is lost and the cell associated with it known as oligodendrocyte is degenerated. A specific feature of this disorder is that it does not degenerate the neurons and its parts. It causes a lesion of demyelination with cavitation in the pons.

     The CSF and the liver function tests show every thing normal but the MRI, CT scan and the Electrolyte examinations reveal the fact.

     It makes the limbs weak and flaccid making the patient disable. As the disease progresses it becomes more evident. It depresses the conscious level of the patient. The depressed conscious level becomes worst and sends the patient in the coma. The disease ends with the death of the patient in coma.


Corpus Callosum Demyelination

     It is a rare but fatal disorder which degenerate a specific part of the brain called Corpus Callosum. The Corpus Callosum joins the two hemispheres of the brain. It is also known as Marchiafava-Bignami Disease.

     The symptoms of this disorder include poor judgment, emotional lability, slowness in movement, disturbance in the walking pattern etc. It is diagnosed in the MRI. This disease progresses to the death.


Alcoholic Dementia

     The long-term alcohol consumption results in the neuronal loss (loss of the brain cells) which can be seen the CT Scan as the atrophy. This loss results in the forgetfulness of the patients known as Alcohol Dementia.



Author: Dr. Krishna N. Sharma
Email: dr.krisharma@gmail.com
Cont: +91-9320699167