Pain causes types and treatment

Pain causes types and treatment

Definition of pain

Someone feels an unpleasant sensation and bad emotional experience associated with actual or potential tissue damage , pain is considered as protective mechanism

Pain is also considered a good sign because it give us attention to the site of the disease which pain arise from it so it can be deal with it to make investigations and treatment that disease causing pain but sometimes the site of the pain not always indicated affection of the subjacent organ

Types of pain

Pain can arise from any part of the body which can be arise from the skin called skin pain or muscle pain nerve pain bone pain visceral pain joint pain ligament pain or cancer pain

Pain may be either acute or chronic pain
  
Acute pain

Which occur suddenly either due to medical or surgical diseases

  

Chronic pain

Which take longer duration than acute one and may persists for long periods such pain may resist to medical treatment such as chronic diseases like osteoarthritis, rheumatoid arthritis or due to behavioral and psychological problems such as depression or anxiety or due to neural changes in the dorsal horn ,spinal cord and brain lead to plasticity of the central nervous system eg phantom limb pain and pain of the peripheral neuropathy

Types of chronic pain

May be skeletal , spinal , joint , muscle or neuropathic eg burning

Commonly back pain and headache

Perception of pain

There is individual variations from person to others to feel the severity of the pain some one may become more sensitive to the pain more than others

This occurs in the thalamus and sensory cortex  which either referred pain or visceral pain such as

Referred pain

In this type of the pain from its name called referred pain in which the pain arise from organ and felt in other site  or is felt somewhere else than the real site of the lesion eg the referred shoulder pain due to diaphragmatic irritation by the phrenic and supraclavicular nerves both arise from the fourth cervical segment

 by mechanism in which the branches of visceral pain fibres synapse in the spinal cord with some of the same second order neurones that receive pain fibres from the skin therefore when the visceral pain fibres are stimulated pain signals from the viscera can be conducted through second neurones which normally conduct pain signals from the skin . the person perceives the pain as originating in the skin itself

Visceral pain

Viscera have sensory receptors for no other modality of sensation except pain , localized damage to viscera rarely causes severe pain , stimuli that cause diffuse stimulation of the nerve ending in a viscus can cause pain which is very severe eg distension of a hollow viscus 

Visceral pain from the thoracic and abdominal cavities is transmitted through sensory nerve fibres which runs in sympathetic nerves these fibres are C fibres which transmit burning and aching pain 

Some visceral pain fibres enter the spinal cord through the sacral parasympathetic nerves including those from distal colon rectum and bladder

Visceral pain fibres may enter the cord by the cranial nerves eg the glossopharyngeal and vagus nerves which transmit pain from the pharynx trachea and upper oesophagus

If a diseases affecting a viscus spreads to the parietal wall surrounding the viscera the pain perceived will be sharp and intense the parietal wall is innervated from spinal nerves including the fast A fibres

 

Pain localization

Visceral pain

Is referred to various dermatomes on the body surface in which the position of the pain feeling depend on the segment of the body from which the organ developed embryologically for example the heart originated in the neck and upper thorax therefore the visceral pain fibres from the surface of the heart enter the spinal cord from cervical 3 to thoracic 5( C3 to T5) that is why myocardial infarction patient feel pain in the neck

also pain from organs derived from the fore-gut is felt in the upper abdomen , pain from organs derived from the mid-gut is felt in the mid-abdomen and pain from organs derived from the hind-gut is felt in the lower abdomen

Parietal pain

Such as from parietal peritoneum the pain is transmitted by spinal nerves which supply the external body surface example is acute appendicitis which start as colic pain around the umbilicus and then shift or move to the right iliac fossa this is due to the nerve supply of the appendix and the umbilical region both arise from the tenth dorsal or thoracic segment of the spinal cord  at first the inflammation is confined to the appendix and the pain is referred to the umbilical area (visceral pain) but later on the peritoneum is involved and the pain is felt over the lesion itself in the right iliac fossa  (parietal pain

Radiating pain

In which the pain shoots from the original focus or lesion site towards other parts sharing the same nerve supply for example renal colic the pain shoots from the lion to the groin testis and inner side of the tight by genitofemoral nerve and also in biliary colic it radiate from the right hypochondirum to the lower angle of the scapula by seventh to ninth thoracic segments

Pain classification

Pain can be classified into either nociception or non nociception

Nociception pain

The physiological experience of pain is called nociception  which may somatic or visceral pain

Somatic pain

In which the pain is felt from the skin muscle joints bone ligaments is termed somatic pain

Any person has pain receptors by which he can feel the temperature (hot or cold) vibration  muscle stretching sprains cut wound or any injury causing tissue damage

Somatic pain commonly well localized and sharp pain and pain become worse or increased by movement or touching the affected area

Visceral pain

In which the pain is felt from the internal body organs or body cavity such as abdominal cavity which containing the small and large intestine liver spleen kidney thorax cavity which containing both lungs and the heart and the pelvic cavity which containing the ovaries urinary bladder uterus

  

The pain receptor feel inflammation stretching and tissue ischemia the visceral pain is poorly localized pain either colicky or cramping pain see above for more details

Non nociception pain

Which means no specific pain receptors

Which either sympathetic or neuropathic or nerve pain

Neuropathic or nerve pain

Which either arise from central nerve system where the pain originated from the nerve between the spinal cord and the brain or from the peripheral nerve system where the pain originated from the nerves between the tissue and spinal cord 

Such pain can be arise from never compression or entrapping eg carpet tunnel syndrome or from nerve degeneration eg brain stroke brain ischemia or from disc herniation or torn which causes nerve compression and inflammation or nerve infection or nerve injury

Sympathetic pain

Which arise from the sympathetic nervous system

This is a type from non nociception pain in which there is no specific pain receptors which commonly arise from bone fractures or soft tissue injuries of the upper or lower limbs

What are the harmful effects of untreated acute pain

If the acute pain not treated rapid it may causing the following effects on the different body system such as

Cardiovascular effects

The pain can causes raised pulse rate tachycardia and elevated blood pressure hypertension and increased myocardial oxygen consumption which is very serious in cardiac patient or patient with myocardial infarction

Respiratory effects

The patient become unable to cough adequately lead to sputum retention chest infection atelectasis 

Gastrointestinal effects

Reduced gastric emptying and bowel movement lead to vomiting and ileus

Genito-urinary effects
Urine retention

Musculoskeletal effcts

Muscle spasm and immobility

Psychological effects

Anxiety ,fear and sleeplessness

Neuroendocrine effects

Secretion of catecholamines such as adrenaline and catabolic hormones leading to increased metabolism and oxygen consumption which promotes sodium and water retention and hyperglycemia

Cancer pain

This type of pain arise either from either the cancer itself which rare cancer causes pain or from the cancer secondaries or metastasis which is common causing pain such as bone pain or visceral pain the cancer pain characterized by it is severe boring constant pain not relieved by rest or usual analgesic may need for narcotic for relieved it is due to a combination of neuropathic pain due to invasion of the nerve and nociception due to tissue damage

Treatment of pain

Pain treatment depend on the causes of the pain and on types of pain either acute or chronic pain see here

  

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