CSI 14+15 Flashcards
What is non specific back pain?
Back pain with an unidentifiable cause
What is back pain often due to?
Sprains or strains
What can back pain more rarely be caused by?
A slipped/prolapsed disc
Sciatica
How is somatotrophic organisation arranged?
Contralaterally
Where does decussation occur for contralateral arrangement?
Medulla oblongata
What side of the body does each side of the somatosensory cortex represent?
The right side represents the left side of the body and the left side represents the right side of the body
What can stimulation of the cingulate cortex cause?
Aversion
What can stimulation of the insula cause?
Vasoconstriction, sweating
What can stimulation of the amagdyla cause?
Fear
What can stimulation of the reticular formation cause?
Arousal
What is the process by which a stimulus is converted to an action potential?
Transduction
What type of receptors need a larger stimulus to be activated?
Pain receptors/nocireceptors
What are the different types of stimuli that can activate pain receptors?`
Thermal
Chemical
Mechanical
Where are mechanoreceptors usually found?
Plasma membrane of high threshold nerve endings
How are mechanoreceptors activated?
They undergo conformational change when a mechanical force is applied which triggers an action potential
How are chemoreceptors activated?
They undergo conformational change in response to certain cytokines being released at the site of inflammation
What path does touch take?
Dorsal column medial lemniscus pathway
What path does pain take?
Spinothalamic tract
What are the different routes in the spinothalamic tract for?
The fast one is for sharp pain
The slow one is for dull pain
What fibres carry sharp pain in the spinothalamic tract?
A delta fibres
What fibres carry dull pain in the spinothalamic tract?
C fibres
How are a delta and c fibres in the spinothalamic tract different?
They have different speed limits due to difference in thickness and myelination
Describe where the spinothalamic tract decussates and synapses along its path?
It immediately synapses and decussates upon entering the dorsal horn
It then travels contralaterally and synapses in the thalamus
What is special about the pathway for dull pain?
It is involved with the reticular formation when it ascends
What does the reticular formation usually cause? How is this related to pain?
It causes arousal, this explains why pain can keep you up at night
Why do muscles flinch when we experience sharp pain?
Because there is a pain relfex arch
What are the 3 types of back pain?
Mechanical
Radiculopathy
Corda equina syndrome
Describe mechanical back pain
Most common (80% of back pain is this type) Problem is in the vertebra, ligaments or muscles
Desrcibe radiculopathy
Unilateral symptoms
Pain is localised
One spinal nerve is affected
There may be weakness, loss or change in sensation in an area
What type of back pain is sciatica?
Radiculopathy
What commonly causes corda equina syndrome (CAS)?
Herniated or slipped disc
What is the pattern of pain in CAS?
Usually bilateral if the disc goes backward or centrally
How common is CAS
Very rare
What is it important to focus on in back pain to rule out CAS?
New symptoms like leg pain
They may have long standing back pain but newly developing symptoms can indicate CAS
What are the usual symptoms in CAS?
Must have bilateral pain Bladder and skin nerves are usually affected Sexual dysfunction Loss of anal tone Reduced perianal sensation Bladder problems
Why does CAS cause difficultly initiating mictruition?
Wherever the compression is the nerves below are affected, if the compression occurs above S1 (parasympathetic supply to the urinary sphincter) then there will be trouble initiating urination
Where is the sympathetic supply to the bladder?
L1-3
Where is the parasympathetic supply to the bladder?
S1
What does the sympathetic supply to the bladder do?
Contracts the urinary sphincter therefore stopping urination
What does the parasympathetic supply to the bladder do?
Relaxes the urinary sphincter therefore initiating urination
How will problems with urination in CAS present?
Stage 1= changes in urination
Stage 2= urinary retention
Stage 3= overflow incontination
What is overflow incontination?
When pressure in the bladder is so high it overcomes the sphincter
What are the red flag symptoms for CAS?
Bilateral sciatica
Severe progressive bilateral neurological deficit for the legs
Difficulty initiating urination
Loss of sensation of rectal fullness
Perianal, perineal or genital sensory loss
Laxity of anal sphincter
What are some ways progressive bilateral neurological deficit for the legs may manifest?
Foot drop
Motor weakness with knee extension
Ankle eversion
Foot dorsiflexion
What can CAS cause permanently?
Urinary incontinence
Faecal incontinence
Leg weakness
Why is it so important to scree for CAS and document in patients with backpain?
Due to the possibility of permanent damage patients are more likely to sue their doctors if it isn’t caught and payout can be huge
Can CAS pain be unilateral?
Yes, in rare cases where the herniated/slipped disc travels laterally
What is COPD?
The name for a group of lung conditions that cause breathing difficulties
What does COPD encompass?
Emphysema= damage to air sacs in the lungs
Chronic bronchitis= long term inflammation of the airways
What are the main symptoms of COPD?
Increasing breathlessness particularly when active
Persistent chesty cough with phlegm
Frequent chest infections
Persistent wheezing
What are some causes of COPD
Mainly smoking
Long term exposure to harmful fumes or dust
Genetic problem that makes the lungs more vulnerable
What are the main treatments for COPD?
Stopping smoking
Inhalers and medication
Pulmonary rehab (specialised programme of exercise and education)
Surgery or lung transplant
What is an exacerbation?
A deterioration from an individual’s baseline
What is seen on a chest x ray when someone has pneumonia?
Opacification which is due to fluid build up
What do clavicles pointing up on a chest x ray indicate?
Hyperinflation of the lungs
What does a slightly lower diaphragm on a chest x ray indicate?
Hyperventilation
What does a slightly enlarged heart on a chest x ray indicate? What symptom may be associated with it?
The heart is working harder than usual
May be accompanied by ankle oedema
What is the name of the condition when there is fluid in the lungs?
Pleural effusion
If there is acidemia how do you tell via ABG if its respiratory or metabolic?
Respiratory= high pco2 Metabolic= low hco3
If there is alkalemia how do you tell via ABG if its respiratory or metabolic?
Respiratory= low pco2 Metabolic= high hco3
How is pneumonia diagnosed?
Radiologically
What conditions fall under type 1 respiratory failure?
Pneumonia Pulmonary oedema Pulmonary embolism Pulmonary fibrosis ARDS Aspiration Lung collapse Asthma Pneumothorax Blunt chest trauma
What conditions fall under type 2 respiratory failure?
Reduced respiratory drive Upper respiratory obstruction Severe acute asthma COPD Peripheral neuromuscular disease Exhaustion
What drugs are given in COPD exacerbation?
Bronchodilators (eg salbutamol)
IV antibiotics
IV hydrocortisone
What is CPAP useful for?
If they have trouble breathing in
How does biPAP work and when is it useful?
It gives 2 types of pressures which is important when someone has trouble breathing in and out
Are CPAP and BiPAP invasive or non invasive?
Non invasive
What type of pressure do CPAP and BiPAP provide?
Continuous positive airway pressure
What non drug treatments can be used in COPD exacerbation?
Oxygen
Sit them upright so they can inflate well
Respiratory physiotherapist
When is biPAP used?
When there is co2 retention and/or pump failure
In CPAP and BiPAP which pressure is greater our of inspiratory and expiratory?
Inspiratory
Describe how hypoxia leads to ankle swelling
Pulmonary hypoxia Pulmonary vasoconstriction Increased pulmonary vascular resistance Pulmonary hypertension Increased right ventricle afterload Right ventricular failure (blood doesn't return to the right ventricle properly so there is backflow in the body) Peripheral oedema Ankle swelling
How are ABGs interpreted?
First identify if its an acidosis, alkalosis or normal
Next identify if its metabolic or respiratory by looking at pco2 and hco3
What is pco2 and hco3 in respiratory acidosis?
pco2 is high
hco3 is also high
What is pco2 and hco3 in respiratory alkalosis?
pco2 is low
hco3 is also low
In metabolic acidosis what is hco3?
low
In metabolic alkalosis what is hco3?
high
How is co2 mostly carried?
In RBCs
What is metabolic acidemia caused by?
increased H+ or reduced hco3-
What is used to determine the cause of metabolic acidaemia?
The anion gap
How is the anion gap calculated?
[Na+]-[hco3-]-[cl-]
What is the usual range for the anion gap?
8-16 mmol/L
What is the usual range for the anion gap when [K+] is included?
12-20 mmol/L
What is the main cause of a high anion gap?
Metabolic acidosis eg lactic acidosis, ketoacidosis, toxins, and renal failure
Why do high anion gaps arise?
high unmeasured anions or H+ reacting with hco3-
Why do normal anion gaps arise?
Because lost hco3- is replaced with chloride ions
What is the main cause of a normal anion gap?
Diarrhoea and renal tubular acidosis
How is a metabolic acidosis compensated?
Increasing ventilation so pco2 falls, h2co3 falls, pH rises
How is a respiratory acidosis compensated?
Kidney retains more hco3- and excretes more h+ to increase pH
