Biological Crintal Illnesses

Question 1

What is pH

Answer 1

A scale that measures of acidity or alkalinity of a solution

A measure of the concentration of FREE H+

The pH range is from 1-14

The pH of distilled water is 7.0

The body’s pH is rigorously regulated as an excess of H+ or OH can be very destructive

Question 2

PH of plasma, interstitial fluid and intracellular fluid

Answer 2

Cells are constantly producing H+ as a byproduct of their metabolism

Intercellular pH 7.35-7.45

Extracellular space pH 7.35

Cell pH 7.0

Question 3

What are acids

Answer 3

Substances which release hydrogen ions when in solution

The stronger the acid the lower the pH

Hydrochloric acid pH 1.2 = a strong acid

Question 4

Carbonic acid

Answer 4

PH 4.68 a week acid

Question 5

What are bases

Answer 5

Substances which

Accept hydrogen ions or
Donate an hydroxyl group when is solution

Question 6

What is acid / base balance

Answer 6

An individual is in acid/base balance when the production of hydrogen ions in the body is offset by the loss from the body

The normal pH range for arterial blood is

pH 7.35-7.45

Question 7

Allalotic

Answer 7

Too little H+ or too much HCO3

pH >7.45

Question 8

Acidic

Answer 8

Too much H+ or too little HCO3

pH <7.35

Question 9

Buffers

Answer 9

Buffers

Mop up excess H+ within seconds

Consist of a weak acid/alkali and it’s salt

Functions to prevent big changes in body fluid pH

Some buffers remain locally, while others are involved in the transport and excretion of H+

Question 10

Buffers

Answer 10

The main buffering system in the body are

Carbonic acid bicarbonate : bicarbonate is a significant anion in both intracellular and extracellular fluid

Proteins: most abundant in tissue cells and blood

Phosphates: most abundant intracellular space and important for excreting H+ in urine

Question 11

Excretion of H+

Answer 11

Once successfully buffered the H+ is transported around the body and is excreted by the

Lungs (fast excretion of volatile acid)

Kidneys (slow excretion of fixed acid)

Question 12

Respiratory system and pH

Answer 12

The respiratory system can change the amount of carbon dioxide in the blood in minutes

A rise in pCO2 stimulates chemoreceptors in the medulla oblongata leading to an increase in RR this removes co2 and increases the pH

Suppression of the respiratory drive leading to fewer shallower breaths will see a rise in CO2

Question 13

Respiratory system and pH

Answer 13

Respiratory acidosis

When the respiratory system fails to remove all the carbon dioxide generated by the tissues, CO2 accumulates resulting in hypercapnia

Usual cause are CNS depression from stings, injury or disease
Asphyxia
Hypoventilation due to pulmonary, cardiac, musculoskeletal, or neuromuscular disease

Question 14

Respiratory system and pH

Answer 14

Respiratory alkyosis when the respiratory system removes too much carbon dioxide, hypocapnia

Usual causes
Hyperventilating due to anxiety, pain or improper ventilator settings
Respiratory stimulation caused by drugs, disease, hypoxia or fever

Question 15

Renal excretion of H+

Answer 15

The kidney controls pH by controlling the amount of H+ excreted in urine, while retaining bicarbonate ions in the blood

Urine pH 4.5-8.0

Hours to days to take effect

Question 16

Metabolic alkalosis cause

Answer 16

Relatively rare, elevated bicarbonate levels

Repeated vomiting - pyloric stenosis

Ingestion of large quantities of antacids

Salicylate poisoning

Question 17

Normal child blood gas values

Answer 17

PH 7.34-7.45

Question 18

Reading blood gases

Answer 18

Look at pH

Look at the PCO

Look at the bicarbonate level

Question 19

Summary

Answer 19

A if/ base balance is key to all body system

H+ is damaging in higher concentrations

There are buffering systems in the body to protect against increased acidity and to enable H+ to be excreted

Blood gas analysis helps to identify the cause of the problem when there is an acid: base disturbance

Question 20

What does the cardiovascular system do

Answer 20

Delivers oxygen and nutrients to all tissues

Transports waste and co2 away from all tissues

Controls BP

Modifies bloody temp

Transports chemical messengers or hormones

Modifies it’s capacity according to demend

Question 21

Cardiac output and mean arterial pressure

Answer 21

Cardiac output = heart rate x stroke volume

Mean arterial pressure = DBP + 1/3 pulse pressure

Question 22

The cardiovascular system in children

Answer 22

When compared to adults, children have faster testing pulse

Smaller stroke volume

Narrower piles pressure

Lower blood pressure

Question 23

Shock, cellular hypoxia and acidosis

Answer 23

Shock in all it’s forms results in the following cascade of biological events

Hypoxia = ATP production falls

Cells revert to anaerobic metabolism to generate ATP= lactic acidosis builds up

Cell membranes become damage as swell, ionic distribution is deranged

Blood pH falls as buffering systems are overwhelmed

Cells die and releasing contented to ECF

Question 24

Types of shock

Answer 24

Hypovolaemic shock - decreased circulating volume

Cardio genie shock - failure of the heart to pump

Distributive shock - increased peripheral vasodilatation
.septic shock
.anaphylactic shock
.neurogenic shock

Question 25

Stages of shock

Answer 25

Compensatory stage Sympathetic nervous system and the renin/angiotensin system helps to maintain blood pressure Progressive stage : compensation fails, BP falls, perfusion Beyoncé’s grossly inadequate Irreversible stage Multi- organ failure and death

Question 26

Early stages of shock

Answer 26

Clinical features Tachycardia- maintain cardiac output Tachypnoea- meeting o2 demand and excrete co2 Mottled, pale, cool periphery - peripheral vasoconstriction/ resistance to maintain BP Wide temperature gradient > 4 °c - cold peripheries due to Lowe peripheral perfusion High Capillary refill time - low peripheral perfusion Skin turgor low extracellular fluid Sunken eyes/ fontanelle - low extracellular fluid

Question 27

Compensatory phase of shock

Answer 27

Cardiac output falls Release of renin Release of aldosterone Disengorgement of spleen Increased blood volume Increase cardiac output

Question 28

Shock progressive stage

Answer 28

Hypotension = hallmark of progressive stage Increased work of heart and cardiac output decreases = heart failure Perfusion yo vital organs insufficient = organ damage and multi organ failure Acute renal failure = oliguria/ anuria Barriers in the gut break down= sepsis/ bleeds Very poor prognosis at this stage

Question 29

Irreversible stage of shock

Answer 29

Mass vasodilation : final common pathway for all types of shock Multi organ failure: heart, hepatic, renal, respiratory, pancreatic, GI, haematological and neurological failure Organs not responding to treatment Death is imminent

Question 30

Hypovolaemic shock

Answer 30

Primary cause is reduced intravascular volume by 25% Most common cause of shock in children Causes D and V Haemorrhage Peritonitis Bowel obstruction Burns

Question 31

Treatment of hypovolaemic shock

Answer 31

Optimis ventilation and oxygenation Fluid replacement - crystalloid or colloids - blood or blood products Cardiac support drugs -inotropes

Question 32

Cardio genie shock

Answer 32

Heart failure is the primary cause of the shock Heart ceases to function as an effective pump Poor prognosis Congenital heart disease Heart valve disease Cardiomyopathy

Question 33

Treatment of cardio genie shock

Answer 33

Oxygen administration Cardiac support drugs Treat arrhythmias Diuretics and strict fluid balance

Question 34

Distributive shock

Answer 34

Increased peripheral vasodilataion Three types fall under this am category Septic shock Anaphylaxis Neurogenic shock

Question 35

Septic shock will

Answer 35

Due to the overwhelming infection Immune response results in a cascade of chemical inflammatory mediators leading to mass vasodilation and tissue oedema Vascular permeability increases, causing leakage of fluid into extra vascular space se Coagulation can occurs and microthrombi may obstruct blood flow to some organs- called disseminated intravascular coagulation

Question 36

Treatment of septic shock

Answer 36

Oxygen mechanical ventilation Fluid administration Inotropic support Antibiotics Correction of acidosis Correction of clotting problems

Question 37

Anaphylactic shock h

Answer 37

Acute, extensive reaction to allergens Degranulation of mast cells with Overwhelming release of histamine ``` Flushing Itching Facial swelling Urticaria Wheeze Strider Abdominal pain Diarrhoea ```

Question 38

Treatment of anaphylaxis

Answer 38

Remove or reduce exposure of causative agent Maintain gaseous exchange, oxygenation, tissue perfusion and cardiac output ``` Adrenaline Antihistamine Corticosteroids Oxygen Fluid resuscitations ```

Question 39

Neurogenic shock

Answer 39

Caused by anything that affects vasomotor output - stimulates parasympathetic activity Inhibits sympathetic activity * spinal injury * spinal anaesthesia * poisons/depressive drugs

Question 40

Treatment of neurogenic shock

Answer 40

Support BP with inotropes Treat increased intracranial pressure of present Management of underlying cause

Question 41

Multi-organ failure

Answer 41

Final pathway of all forms of shock GIT vasoconstriction > blood flow diversion away from GI tract > gut is harm is > ulceration and bleeding Liver hypoxia > cellular dysfunction > metabolic wastes not being detoxified and gluconeogenesis fails Kidneys acute tubular necrosis > oliguria, then anuria, then polyuria

Question 42

Summary

Answer 42

The cardiovascular system in children has differing ranges of normal values based on age Shock is a syndrome that is seen in a range of conditions Compensation occurs Unless shock is adequately treated then it progresse and death my ensue An understanding of the cause of shock is key to optimal treatment

Question 43

GOT review

Answer 43

Oral cavity, teeth, tongue Salivary glands Pharynx Esophagus Stomach Liver Gallbladder Pancreas Small intestines Large intestines

Question 44

GIT review

Answer 44

Functions of the digestive system Ingestion Mastication Propulsion Mixing Section Digestion Absorption Elimination

Question 45

Gut fluid dynamics

Answer 45

Enterocytes Cell membranes and ion pumps Secretion Absorption Production of faeces

Question 46

Gut defence mechanisms

Answer 46

Fluid volume Gut motility Anatomical barriers: mucous, glycocaylix Constant shedding of epithelial cells Gastric acid barrier Microbial flora (good bacteria) Mucosal and luminal IgA Lymphatic

Question 47

Immature GI tract in children

Answer 47

Reduced gut acidity Reduced gut motility Reduced IgA secretion Increased permeability of mucosa Prone to gastro oesophageal reflux

Question 48

Breast milk and gut production

Answer 48

Enhances gut maturation Provision of white blood cells Bacteriocidal Bacteriostatic

Question 49

Gastroenteritis

Answer 49

Inflammation of the mucous membranes of the GIT, chnaracterisednby vomiting and or diarrhoea Dehydration, electrolyte imbalance and metabolic acidosis are accompanying features of gastroenteritis

Question 50

Common causative agent

Answer 50

Bacteria •escherichia coli •salmonella •shigella sonnei ``` Viruses •rotavirus •adenovirus •hepatitis A •small round structured virus’s (SRVs) eg norovirus ```

Question 51

Modes of transmission

Answer 51

Water Food Person to person ``` vector Finger Flies Food Fluid Faeces ```

Question 52

Microbial pathogensis

Answer 52

Microbe gains entry to gut Survives non specific defences Adheres and attached to gut wall Multiplies, indueces pathology

Question 53

The onset of diarrhoea

Answer 53

Normal absorption in the GI tract abruptly stops Vomiting and diarrhoea starts Loss of undigested food and fluids Loss of GI tract secretions Loss of large quantities of water from bowel walls Dehydration Electrolyte imbalance Metabolic acidosis

Question 54

Diarrhoea

Answer 54

Defined as a change in bowel habit for the individual child resulting in substantially more frequent and or looser stools Acute diarrhoea is usually caused by GI infection Profuse, liquid/watery consistency Pea green Abdominal pain Blood Mucous

Question 55

Other conditions which may present as suspected gastroenteritis

Answer 55

Systemic infection : septicaemia Local infection : RTI, otitis media, uti, hepatitis a Surgical disorders : pyloric stenosis, appendicitis Diabetic ketoacidsis Other allergy’s

Question 56

Water diarrhoea viruses

Answer 56

Gain access into gut wall multiply inside enterocytes Destroy or shorten villi disrupt fluid and electrolytes balance Cause excessive secretions Reduce re absorption

Question 57

Bloody diarrhoea

Answer 57

Invade and adhere to gut wall Replicate in abundance Produce enterotxins Activate gut secretion Cause intestinal hurt Hinders re absorption Inflammation and haemolysis

Question 58

Incubation periods

Answer 58

Salmonella 12-3 days Clostridium botulinum 12 hours -1 1/2 days Rotavirus 1-2!days

Question 59

Investigations

Answer 59

Stool MC&S inculcated when Blood or mucus is present in the stools Septicaemia is suspected The child is immunocompromised Consider when Child has recently been abroad Has prolonged barrows more than7 days Unsure of diagnosis Bloods U&Es in severe dehydration

Question 60

Dehydration

Answer 60

Negative fluid balance Loss of 3% body weight Levels of dehydration based on loss of body weight -mils 3-5% Moderate 5-10% loss Severe 10%loss

Question 61

Signs of dehydration in children

Answer 61

Prolonged capillary refill Abnormal skin turgor Abnormal respiratory pattern Cold extremities Absent tears Sunken fontanelle Sunken eyes Dry mucous membranes Weak pulse Tiredness and lethargy

Question 62

Investigation in dehydration

Answer 62

If clinically dehydrated, consider Blood for urea and electrolytes Blood for culture Full blood count

Question 63

Oral rehydration solution

Answer 63

A dioralyte sachet contains Glucose Sodium chloride Potassium chloride Disodium hydrogen citrate ORS to have equal efficacy to IVIs ORS reduces stool output and need for IVIs

Question 64

Intravenous fluid thearapy

Answer 64

Usually only recommended for children with severe dehydration I’ve fluid regime is calculated according to the child weight and electrolyte levels A fluid boils may be needed for fluid resuscitation 20ml/kg

Question 65

Return to normal diet

Answer 65

Rapid reintroduction of normal feeding of previously consumed diet after oral rehydration Breastfeeds Full strength milk and formula normal lactose containing diet

Question 66

Evidence based theory

Answer 66

Good evidence Hand washing Breathing Parent education Less evidence Anti diarrhoea drugs Antibiotics Zinc

Question 67

Summary

Answer 67

Gastroenteritis is a significant golabal problem Good public health measures have a significant impact on reducing gastroenteritis Simple measure such as a good hygiene are key Fluid replacement therapy is the mainstay of treatment for dehydration ORS for a short period of time is usually all that is required while the D and V settle then the normal diet can be reintroduced