FRCA Primary Basic Science (2)

FRCA primary basic science

Question: 1 of 53

Time taken: 2 mins 18 secs

The following can be directly measured by spirometry:

True / False

vital capacity Correct

anatomical dead space Correct

residual volume Correct

total lung capacity Correct

functional residual capacity Correct

A spirometer is a device used for measuring lung volumes either directly or indirectly using dilution techniques, e.g. helium. It can also be used to calculate flow rates and the basal metabolic rate. Spirometry provides timed measurements of expired volumes from the lung and is the foundation of pulmonary function testing. Wet and dry spirometers exist, and with automated equipment it is possible to interpret more than 15 different measurements from spirometry alone. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, and the flow between 25% and 75% of the FVC are the most clinically helpful indices obtained from spirometry. The anatomical dead space is measured by Fowler’s method (single breath nitrogen washout); residual volume and total lung capacity can be measured using the body plethysmograph or helium dilution; the functional residual capacity can be measure by nitrogen washout or the helium dilution technique. It should be noted that the helium dilution technique is performed by the patient breathing air with a known concentration of helium, starting from the end of normal expiration from a SPIROMETER! The question asks which can be measured directly, thus the only correct option is vital capacity.

Question: 2 of 53


Gastrointestinal complications related to ITU therapy include:

True / False

Oesophageal erosions Correct

Diarrhoea Correct

Acute acalculous cholecystitis Correct

Increases in pancreatic lipases and amylase Correct

Haemorrhoids Correct

Erosive oesophagitis has an incidence of up to 48% in mechanically ventilated ITU patients. Causative factors include: nasogastric intubation; gastro intestinal reflux; and duodenogastric reflux of bile. Diarrhoea has a similar reported incidence and is due to a number of factors including: Enteral feeding; high feed rates; the administration of hyperosmolar feeds; and carbohydrate fermentation by small bowel bacterial colonisation. Antibiotic related diarrhoea accounts for 50% of cases. Clostridium difficile infection should be excluded in all cases of diarrhoea following antibiotic administration. Other drugs implicated in diarrhoea include H2 receptor antagonists and magnesium containing antacids. Acute acalculous cholecystitis has a reported incidence of up to 3% in ITU patients. Its development is associated with a number of risk factors including: Shock, dehydration; sepsis; multiple blood transfusions; prolonged fasting; and total parenteral nutrition (TPN). In animal models high levels of PEEP (above 15cm) of water have been shown to reduce

pancreatic blood flow and increase the serum levels of pancreatic enzymes, but the link has not been clearly demonstrated in the critically ill. There is no reported increased risk of haemorrhoids in ITU patients.

Question: 3 of 53


In cardiogenic shock complicating myocardial infarction, the following interventions are of proven clinical benefit:

True / False

The administration of positive inotropic drugs Correct

Intra aortic balloon counter pulsation Correct

Early invasive revascularisation Correct

Thrombolysis Correct

Pulmonary artery catheterisation Correct

The only intervention which has conclusively demonstrated an improvement in outcome following myocardial infarction is early invasive angioplasty or stenting. Although the other interventions may be required to produce an adequate blood pressure they have failed to demonstrate an improved outcome. In contrast to the demonstrated efficacy of thrombolysis in uncomplicated myocardial infarction, in post MI cardiogenic shock, thrombolysis may be harmful.

Question: 4 of 53


Computerised axial tomography scans (CT scans) of patients with traumatic head injuries:

True / False

Extradural haematomas are seen more frequently than subdural haematomas Correct opposite

Extradural haematomas are classically biconcave in shape on the scan Correct biconvex in appearance

Diffuse axonal injury is easily identified Correct

A normal scan excludes raised intracranial pressure (ICP) Correct

Evidence of intra-ventricular blood is an indication for referral to a neurosurgical unit Correct

Subdural haematomas are the commonest type of intra-cerebral haemorrhage and occur in 30% of severe head injuries. Extradural haematomas only occur in < 10% of unconscious head injured patients. On computerised axial tomography scans (CT scans) extradural haematomas are classically lenticular or biconvex in appearance, whereas subdural haematomas are classically cresenteric in shape. Diffuse axonal injury is caused by shearing forces on neurones, which subsequently leads to their death. It produces rapid unconsciousness due to its effect on the reticular activating system. Diffuse axonal injury is best demonstrated on diffusion weighted magnetic resonance imaging scans (not CT scans). Although there are classic signs relating to raised intracranial pressure (ICP) on CT scans, a normal scan does not preclude raised ICP. The presence of intraventricular blood particularly in the third and forth ventricles can block CSF drainage and predispose to the development of obstructive hydrocephalus. The decision to insert an intra-ventricular drain should be considered following referral to a neurosurgical unit.

Question: 5 of 53


Positive end expiratory pressure (PEEP):

True / False

Increases pulmonary vascular resistance Correct

Decreases extra-vascular lung water Correct

Increases dead space Correct

May contribute to barotrauma Correct

The protective effects of PEEP on the lung are limited to the oxygen sparing action Correct

Although positive end expiratory pressure (PEEP) may provide an oxygen sparing effect by reducing the intrapulmonary shunt, and increasing alveolar recruitment, it has many deleterious effects including: 1 - Decreasing cardiac output; 2 - Increasing pulmonary artery pressure due to increased pulmonary vascular resistance 3 - Increasing dead space; 4 - Increasing the distension of uninjured lung units increases the risk of barotrauma; 5 - Increasing extra-vascular lung water by decreasing pulmonary interstitial lymph drainage (although PEEP reduces oedema in left ventricular failure and in fluid overload). The protective effects of PEEP on the lung are mediated not only through its ability to decrease the inspired oxygen requirements, but also due to a reduction in repeated alveolar collapse and re-inflation. This limits the shear stress on the alveolar wall, which reduces the formation of pro-inflammatory mediators by the pulmonary vascular epithelium and alveolar macrophages.

Question: 6 of 53


Complications following an interscalene nerve block include:

True / False

Horner’s syndrome Correct

Recurrent laryngeal nerve block Correct

Subarachnoid injection Correct

Vagus nerve block Correct

Vertebral artery injection Correct

Hoarseness can occur following interscalene block due to recurrent laryngeal nerve blockade, and unless it is bilateral it is rarely significant. Diaphragmatic paralysis may also occur during an interscalene block due to phrenic nerve blockade. However, this rarely causes symptoms unless the patient has severe respiratory disease. Horner’s syndrome, subarachnoid injection and vertebral artery injection have all been reported Blockade of the vagus nerve is not a recognized complication following an interscalene block.

Question: 7 of 53


Regarding the management of burns patients:

True / False

parenteral nutrition markedly attenuates the hypermetabolic response Correct

nursing the patient in a cool environment reduces the hypercatabolic state Correct

in a patients with 60% burns, the metabolic rate is four times higher than the normal rate Correct twice the normal rate

bacterial translocation from the intestines occurs 24 hours after a burn injury Correct

high protein diets may improve survival Correct

After suffering a thermal injury, the patient rapidly becomes hypercatabolic, with an increased cardiac output and oxygen consumption. Severe burn injuries are associated with a greater hypermetabolic response. With a 60% total body surface area burn the metabolic rate is about twice the normal rate (not four times greater). Patients should be nursed in temperatures of at least 30 degrees Celsius to reduce energy expenditure (not cool environments). The resetting of hypothalamic thermoregulation results in a 1-2 degree Celsius rise in core temperature. The burned area should be covered to reduce evaporative loss of fluids. The barrier function of the intestine is lost immediately after a thermal injury, allowing the translocation of bacteria and endotoxins, which can occur within hours (not 24 hours after the burn). Early enteral feeding preserves intestinal mucosal integrity and prevents translocation of microorganisms into the circulation. Enteral nutrition is associated with a marked attenuation of the hypermetabolic response to a burn injury (not parenteral nutrition). High protein diets (with a calorie to nitrogen ratio of 100:1), may improve survival after a burn. 50% of the calories should be in the form of carbohydrate, 30% as lipids or fat and up to 20% as protein or amino acids. Despite the associated risk of infection supplementary parenteral feeding may be required.

Question: 8 of 53


When performing a caudal epidural block in a child:

True / False

hypotension is a commonly encountered problem Correct

the sacral cornua forms the lateral border of the sacral hiatus Correct

the dura extends to the lower border of L4 Correct

an intraosseous injection of local anaesthetic may cause profound hypotension Correct

the cauda equina terminates at S2 Correct

Failure of fusion of the laminae of the fifth sacral segment results in the formation of the sacral hiatus. The sacral cornua form the lateral border and the spinous process of the fourth sacral segment forms the superior border. The sacrococcygeal membrane forms the roof of the sacral hiatus (posterior sacrococcygeal ligament). The spinal cord terminates at L1/2. The cauda equina (lumbar and sacral nerve roots), which is covered by the dura, terminates at S2. Hence, the dura extends to the lower border of S2 (not L4). The filum terminale terminates at the coccyx. The complications associated with caudal anaesthesia have a low incidence and are certainly not common. However, an intraosseous injection of local anaesthetic can produce results similar to an intravascular injection, causing profound hypotension or cardiac arrest. Other complications, which are also not commonly encountered include: urinary retention, lower limb blockade, dural puncture and hypotension.

Question: 9 of 53


Damage to the cauda equina may lead to:

True / False

Urinary incontinence. Correct

Weakness of leg muscles Correct

Faecal incontinence. Correct

Sexual dysfunction Correct

Sacral analgesia. Correct

Faecal incontinence, impotence and sacral analgesia are all features of damage to the cauda equina. Weakness of the leg muscles is an early sign and abnormal leg reflexes may occur. Urinary retention rather than incontinence is seen.

Question: 10 of 53


The following are complications associated with regional techniques:

True / False

Supraclavicular block – Horner’s syndrome Correct

Interscalene block – phrenic nerve palsy Correct

Extradural block – total spinal block Correct

Spinal block – anterior spinal artery syndrome Correct

Spinal block – shivering Correct

Phrenic nerve palsy and Horner’s syndrome are seen as a result of both the supraclavicular and interscalene blocks. Failure to recognise a dural puncture or subarachnoid / subdural placement of the epidural catheter during epidural anaesthesia, exposes the patient to the risk of a total spinal. If a large volume of local anaesthetic is injected into the cerebrospinal fluid (CSF), then a total spinal block may occur with rapidly ascending motor and sensory blockade, respiratory paralysis and central apnoea. Anterior spinal artery syndrome may occur as a complication of spinal or subarachnoid block. Shivering after extradural anaesthesia is common, and is thought to be caused by differential nerve blockade, either suppressing descending inhibition of spinal reflexes, or allowing selective transmission of cold sensation. In spinal anaesthesia where the block is denser, shivering is rare.

Question: 11 of 53


Post dural puncture headache:

True / False

Can be successfully treated by epidural blood patch in over 90% of patients. Correct

Is associated with sixth cranial nerve palsy. Correct

Is a postural headache, classically over the frontal or temporal regions Correct

Occurs less often when spinal anaesthesia is performed using a Quinke needle than if a Sprotte needle is used.

Correct

May be treated by strict bed rest Correct

Post dural puncture headache (PDPH) may be associated with nausea, vomiting, photophobia, dizziness and cranial nerve palsies, especially of the sixth cranial nerve. The PDPH is classically frontal or occipital (not temporal) and is exacerbated by standing up from the supine position, coughing or straining. Non-cutting needles e.g. Sprotte, Whitacre or Green, are said to produce a lower incidence of PDPH than cutting needles e.g. Quinke. Over 90% of patients with PDPH can be successfully treated by epidural blood patch. They also prefer to lie flat, but this does not reduce the incidence or duration of the headache following dural puncture, and bed rest is not a recognised treatment.

Question: 12 of 53


Concerning spinal (subarachnoid) anaesthesia:

True / False

Barbotage will increase the spread of the block . Correct

The spread of the local anaesthetic is greater in pregnancy. Correct

In the UK, bupivacaine with a specific gravity of 1.026 is commonly used for spinal blockade. Correct

It is contraindicated in benign intracranial hypertension . Correct

It can impair the ability to cough. Correct

Barbotage involves the repeated aspiration and reinjection of cerebrospinal fluid (CSF) into the syringe whilst injecting the hyperbaric local anaesthetic solution, which increases the spread of the block. Pregnancy increases the spread of the block due to reduced CSF volume and compressed epidural space. In the UK hyperbaric bupivacaine 0.5% (in 8% dextrose) which has a specific gravity of 1.026, is the only hyperbaric local anaesthetic licensed for use in spinal anaesthesia. Epidural and subarachnoid blocks may be safely undertaken in patients with benign intracranial hypertension. Intercostal and abdominal muscle weakness may impair active exhalation and coughing, although tidal volume and inspiratory pressure are maintained by intact diaphragmatic innervation (C3-5).

Question: 13 of 53


Lidocaine:

True / False

Is an amide local anaesthetic and contains an intermediate (-NH.CO-) chain. Correct

Is hydrolysed by plasma cholinesterase before being broken down in the liver. Correct

Has a pKa of 8.1 Correct 7.7 not 8.1

Is achiral. Correct

Transfers across the placenta less than bupivacine. Correct more than bupivacine (not less).

Lidocaine is an achiral amide local anaesthetic and contains a lipophilic aromatic group, an intermediate amide (-NH.CO-) chain and a hydrophilic group.

Amide local anaesthetics are broken down by amidases in the liver, whereas ester local anaesthetics are rapidly hydrolysed by plasma cholinesterase. The pKa of lidocaine is 7.7. In general, highly protein-bound drugs have a low umbilical vein to maternal blood ratio (uv:m). The uv:m ratio for bupivacaine is approximately 0.2; and for lidocaine and Prilocaine it is 0.5. Therefore, lidocaine transfers across the placenta more than bupivacine (not less).

Question: 14 of 53


Regarding chiral local anaesthetics:

True / False

Prilocaine and bupivacaine are chiral compounds. Correct

The S (-) enantiomer usually has higher local anaesthetic activity Correct

The S (-) enantiomer has a longer duration of local anaesthetic activity. Correct

The R (-) enantiomers may have reduced potential for toxicity when compared with the racemic drug. Correct

S (-) bupivacaine is available for clinical use. Correct

Prilocaine and bupivacaine are chiral compounds. Most ester local anaesthetics, as well as lidocaine are achiral. Individual enantiomers have approximately equal local anaesthetic activity, although R (+) bupivacine may be more potent than the S (-) enantiomer. The S (-) enantiomers produce enhanced vasoconstriction and have prolonged local anaesthetic activity; they may also be less cardiotoxic. The S (-) enantiomers (nor R) may have reduced potential for toxicity when compared with the racemic mixture of the drug. Chirocaine is the S (-) enantiomer of bupivacaine and is commercially available for clinical use.

Question: 15 of 53


Field block for inguinal hernia repair:

True / False

Requires blockade of the iliohypogastric and ilioinguinal nerves Correct

Requires blockade of the subcostal nerve Correct

Requires blockade of the genital branch of the genitofemoral nerve Correct

Involves blocking dermatomes S2-S4 Correct

Prilocaine 0.5% with adrenaline is a suitable choice of local anaesthetic agent Correct

A field block for an inguinal hernia repair is ideal for high risk patients unsuited for general or spinal anaesthesia. The innervation of the inguinal region is through the ventral rami of T11 and T12 and the two upper branches of the lumbar plexus, the iliohypogastric and ilioinguinal nerves. The anterior cutaneous branch of the iliohypogastric nerve supplies the skin above the pubis and medial end of the inguinal ligament. The ilioinguinal nerve supplies the skin over the root of the penis and scrotum. The ventral ramus of the 12th thoracic or subcostal nerve sends a branch to join the first lumbar root and supplies the skin over the lower anterior abdominal wall. The genital branch of the genitofemoral nerve may supply skin in the medial part of the groin. Prilocaine 0.5% with adrenaline is a suitable choice of agent, which allows a large volume of solution to be used safely.

Question: 16 of 53


Concerning Intravenous Regional Anaesthesia (IVRA - Bier’s Block):

True / False

The use of a double cuff prevents any chance of systemic toxicity if it remains inflated for at least 20 minutes. Correct

Pre-operative starvation of patients is not necessary. Correct

Methaemoglobinaemia may be seen after IVRA using 40mls of 0.5% prilocaine Correct

Bupivacaine or prilocaine are most commonly used due to their long duration of action. Correct

Bier’s block can be performed on the lower leg for some types of ankle or foot surgery Correct

There have been reports of convulsions and systemic side effects despite a functioning double cuff. This may be due to rapid injection of local anaesthetic achieving injection pressures higher than the tourniquet occlusion pressure, resulting in systemic leakage causing high plasma levels of local aneasthetic. Interosseous leakage and poor exsanguination of the limb may also contribute to this. It is recommended that the patient is fully starved prior to IVRA or any regional block, due to the risks of systemic toxicity. Neither systemic toxicity nor methaemoglobinaemia have ever been reported at this dose of prilocaine. Bupivacaine should not be used because of the risk of cardiotoxity. Prilocaine is the recommended agent for IVRA, but lidocaine has also been used. With a tourniquet placed at mid-calf level, the technique of IVRA and dose of local anaesthetic used is identical to that of upper limb Bier’s block. IVRA of the lower limb is much less widely used and it is said that the anaesthesia is less reliable than when performed on the arm.

Question: 17 of 53


When setting initial ventilator settings in Critical Care:

True / False

an oxygen concentration of 60% should be used to avoid oxygen toxicity Correct

positive end-expiratory pressure (PEEP) should be titrated against pCO2 Correct

the pCO2 should be targeted and not the pH Correct

a tidal volume of less than 5ml per kg should be used to prevent volutrauma Correct

neuromuscular blockade may need to be used Correct

The initial oxygen concentration delivered to the patient should be 100% (or an FIO2 of 1.0) which can then be titrated down. Positive end-expiratory pressure should be titrated against pO2 (not pCO2). The minute ventilation should be used to target pH, permissive hypercapnia may be used. Tidal volumes should be about 8 ml per kg. Using tidal volumes of <5ml per kg does prevent volutrauma, but also results in hypoventilation. Many patients can be ventilated providing they are adequately sedated, which subsequently allows neuromuscular blockade to be reserved for difficult patients.

Question: 18 of 53

Time taken: 1 hrs 2 mins 3 secs

A high mixed venous oxygen saturation (SvO2) may be caused by:

True / False

sepsis Correct

anaemia Correct

hyperthermia Correct

shivering Correct

cardiogenic shock Correct

A mixed venous oxygen saturation (SvO2) >80% is considered high, and is caused by high oxygen delivery e.g. a high FiO2 and a decreased O2 demand e.g. anaesthesia, hypothermia and decrease O2 tissue uptake (as in sepsis).

Question: 19 of 53


IgE:

True / False

Is present in plasma in the same concentration as IgG Correct

Is increased acutely in an asthmatic attack Correct

Crosses the normal placenta Correct No

Is increased in the serum of atopic individuals Correct

Is involved in type 2 hypersensitivity Correct type I hypersensitivity reaction (not 2).

IgG is the predominant form of immunoglobulin in plasma at a concentration around 10,000 times greater than IgE. IgG crosses the placenta to confer immunity to the fetus ( not IgE). IgE is involved in arming mast cells and basophils. IgE causes mast cells to release vasoactive amines, such as histamine, producing an inflammatory response which can result in a type I hypersensitivity reaction (not 2). IgE is responsible for allergen-mediated diseases such as anaphylaxis, asthma and atopy. Total serum IgE is frequently increased in those with atopy, but serum IgE does not rise acutely during an asthmatic attack.

Question: 20 of 53


Magnesium:

True / False

causes vascular smooth muscle relaxation Correct

is predominantly an intracellular cation Correct

is a tocolytic Correct

potentiates deep tendon reflexes Correct

is used as an anticonvulsant Correct

Magnesium is largely an intracellular cation, present mainly in bone and skeletal muscle. Only 1% is in the ECF and normal plasma level are 0.75 – 1.05 mmol/l. Its effect can be described as antagonising the actions of calcium. Magnesium sulphate is used in pre-eclampsia as an anticonvulsant but it also relaxes vascular smooth muscle, causing vasodilatation thus lowering the mean arterial blood pressure. It is also an effective tocolytic drug helping to decrease uterine contractions. It acts at the neuromuscular junction decreasing acetylcholine release thus neuromuscular function is weakened. Therapeutic plasma levels of magnesium are 2.0 - 3.5 mmol/l, but side effects may occur above 4.0 mmol/l. Increasing plasma levels of magnesium cause deep tendon reflexes to gradually diminished until they become absent. Thus tendon reflexes are frequently used as a bed-side measurement of hypermagnesaemia.

Question: 21 of 53


Regarding a LASER:

True / False

Is an acronym for Light Amplification of Stimulated Ejection of Radiation. Correct Emission

Produces multichromatic light. Correct monochromatic

Requires a pair of mirrors at opposite ends of a optical cavity containing the lasing medium Correct

The wavelength is determined by the stimulating current Correct The lasing medium notthe current

The lasing medium can be gaseous or crystalline. Correct

Is an acronym for Light Amplification of Stimulated Emission of Radiation. A Laser produces a highly directional beam of coherent (monochromatic) electromagnetic radiation. Photons of energy produced from energised atoms in the lasing medium are reflected back and forth many times between the mirrors amplifying their number. The lasing medium determines the wavelength of electromagnetic radiation emitted. The lasing medium is most commonly gaseous but may be crystalline.

Question: 22 of 53


Regarding polycythaemia:

True / False

It may be caused by smoking. Correct

There is a reduced risk of DVT. Correct

There is often splenic enlargement Correct

There is an increased risk of myocardial infarction. Correct

Gastrointestinal haemorrhage may occur. Correct

Polycythaemia is an increase in the concentration of red blood cells above the normal level. Polycythaemia may be primary, secondary (chronic hypoxia stimulates erythropoetin), relative (reduced plasma volume, normal red cell mass) or inappropriate (inappropriate erythropoetin production). Polycythaemia leads to increased blood viscosity and sluggish blood flow, resulting in increased risk of myocardial infarction, stroke, ischaemic limbs and DVT. Approximately 75% of patients will have splenic enlargement. Peptic ulceration is common in polycythaemia rubra vera (primary). Haemorrhagic lesions may be a feature of the condition, especially of the GI tract.

Question: 23 of 53


Regarding hyperventilation:

True / False

it may cause an increase in the blood pH Correct

it may occur following cerebral injury Correct

it raises the pCO2 of arterial blood Correct

it decreases the pO2 of arterial blood Correct

it decreases concentration of ionised calcium Correct

Hyperventilation is associated with a respiratory alkalosis that will raise the blood pH, lower arterial pCO2 and may elevate the arterial pO2 (not decrease). Cerebral injury may initially precipitate hyperventilation, although depressed respiration and hypoventilation is the predominant feature. The raised pH reduces ionised calcium concentrations, which is why tetany can occur in association with hyperventilation.

Question: 24 of 53


Immunoglobulins:

True / False

Contain antigen-binding sites derived solely from the light chains Correct

Contain Fc regions derived solely from the heavy chains. Correct

Are chiefly of IgA class at mucosal surfaces. Correct

Are produced by T lymphocytes as well as B lymphocytes Correct

IgE confers protection against parasitic worms. Correct

The antigen binding sites on immunoglobulins are composed of the hypervariable regions of both heavy and light chains which together make the complementarity determining region (CDR) of the antibody. The Fc is made up of two H chains, linked by disulphide bonds. IgA (actually IgA2), constitutes the major antibody in secretions, and bathes mucosal surfaces. IgA1 is mainly confined to the serum. Only B lymphocytes are capable of synthesising antibodies, as are plasma cells. Worm antigens are constantly being released, and attach to specific IgE antibody that in turn has attached to mast cells by their receptor for IgE. Interactions with IgE results in mediator release by the mast cell, one effect of which is contraction of smooth muscle, which is intended to expel the parasite from the gut.

Question: 25 of 53


Regarding acquired (adaptive) immunity:

True / False

Immunological recognition is an important component. Correct

Antibody is produced by T cells. Correct

Recognition of antigen by B cells is mediated by antibody. Correct

Antibodies produced in response to infection recognise more than one epitope on the surface of the invading micro-

organisms. Correct

Elimination of intracellular micro-organisms is dependent on antigen. Correct

The B cell receptor is an immunoglobulin of the same specificity as the one the cell is programmed to make. Antigen binding to this leads to B cell activation and antibody production. The elimination of intracellular micro-organisms is cell mediated and depends on affected cells displaying particular antigens at their cell surface allowing the killing of the cell by antigen-specific cytotoxic T-cells. Antibodies produced in response to infection recognise more than one epitope on the surface of the invading micro-organisms.

Question: 26 of 53


Cryoglobulins:

True / False

cause red cell agglutination at 4°C Correct

are a cause of arterial thrombi Correct

are seen in mycoplasma pneumonia Correct

are seen in subacute bacterial endocarditis Correct

are associated with hepatitis B and C Correct

Cryoglobulins are immunoglobulins that reversibly precipitate below 10°C, they are not cold agglutinins. They may cause:

hyperviscosity and vasculitis, Raynauds, arterial thrombi, gangrene, retinal haemorrhages. Three tyes exist: Type 1 are

usually IgM/IgG (monoclonal) which are seen in Waldenstrom's, lymphoproliferative disease; Type II (monoclonal IgM

rheumatoid factor plus polyclonal IgG) are seen in bacterial endocarditis, Hepatitis C, Hepatitis B, Epstein-Barr, and CMV;

Type III (polyclonal IgM rheumatoid factor plus polyclonal IgG) are seen in spirochaetal disease, coccidiomycosis, malaria,

SLE, rheumatoid, Sjogrens, scleroderma and mixed essential cryoglobulinaemia. Cold agglutinins cause red cell

agglutination at 4°C and may be seen in mycoplasma pneumonia.

Question: 27 of 53

T cells:

True / False

survive for two weeks Correct

possess surface immunoglobulin Correct

secrete IL-2 when activated Correct

secrete immunoglobulin Correct

recognise native antigen. Correct

T cells have characteristic surface glycoproteins and their own form of receptors. Helper T cells recognise foreign antigens in association with HLA class II antigens on presenting cells. Survival of T cells varies from several weeks to the lifetime of an individual, such as the T cells in thymus. They secrete IL-2 when activated. B-lymphocytes express immunoglobulins on their surface and secrete immunoglobulins (not T cells).

Question: 28 of 53


A pre-operative 12 lead ECG is required in the following patients:

True / False

a 40-year-old female with essential hypertension Correct

a 30-year-old male for an inguinal hernia repair Correct

a healthy 45-year-old male who smokes 20 cigarettes per day Correct

an obese 35-year-old male with exercise induced dyspnoea Correct

a 50-year-old female with a permanent pacemaker for a knee replacement Correct

As a rule all patients over the age of 40 require a 12 lead ECG preoperatively, even if a history of cardio-respiratory disease is absent. Hypertension can cause left ventricular hypertrophy which can be identified on the ECG by a large R wave in V6 and large S wave in V1 (combination greater than 35 mm). Patients with permanent cardiac pacemakers always require a preoperative 12 lead ECG, in addition to a pacemaker check 6 months prior to elective surgery. Useful information can be obtained from the ECG about the type of pacemaker and its programming. Dyspnoea may be secondary to cardiac rather than respiratory disease making an ECG essential. The usual speed of recording of an ECG is 25 mm per second and the calibration is 1 milivolt per cm.

Question: 29 of 53


Regarding urine or urine production:

True / False

urine production is normally about 1 ml per kg per day Correct

oliguria is defined as urine production of less than 0.5 ml per kg per hour Correct

large doses of intravenous propofol may turn the urine green Correct

the pigments urochrome and uroerythrin give urine its yellow colour Correct

urine normally contains bilirubin Correct

Urine is coloured yellow by the pigments urochrome and uroerythrin, but it darkens on standing due to the oxidation of urobilinogen to urobilin. Abnormal constituents of urine include glucose, ketones, bilirubin, erythrocytes, large numbers of leucocytes and casts. The urine of patients on longterm sedation using propofol is frequently coloured green. Normal urine output in temperate climates is 800 – 2500 ml per day, which is about 1 ml/kg per hour. Despite the concentrating ability of the kidney, a minimum of 500 ml/day is required to eliminate the urea and other electrolytes. Oliguria is defined as a urine production < 0.5 ml/kg per hour (approx less than 50mls), and may indicate hypovolaemia or renal failure.

Question: 30 of 538118

Hypothermia:

True / False

is a core temperature of less than 34°C Correct less than 35°C

is rarely seen in children as they have a higher basal metabolic rate Correct

can cause atrial fibrillation Correct

can cause J waves on the ECG Correct

is commonly associated with alcohol intoxication Correct

Hypothermia is defined as a core temperature of less than 35°C. Children have a relatively large body surface area to weight ratio and even thought they have a higher basal metabolic rate, they are very susceptible to hypothermia. Alcohol and anaesthetic gases cause vasodilatation thus increase heat loss. As the core temperature continues to fall the cardiac rhythm becomes increasingly unstable, sinus bradicardia tends to give way to atrial fibrillation followed by ventricular fibrillation and finally asystole. In hypothermic patients, J waves are frequently seen on the ECG.

Question: 31 of 53


8117

Hypercalcaemia is associated with:

True / False

hypoparathyroidism Correct

thiazide diuretics Correct

hyperthyroidism Correct

sarcoidosis Correct

adrenocortical insufficiency Correct

Hypercalcaemia is commonly caused by hyperparathyroidism and malignant tumours (especially bone secondaries). Less common causes include milk-alkali syndrome, hyperthyroidism, sarcoidosis, adrenocortical insufficiency, immobilization and thiazide diuretics.

FRCA Primary Basic Science (2)

Documents

Transcript of FRCA Primary Basic Science (2)