Internal medicine Flashcards

Question

22.2 Of the following, the congenital condition LEAST commonly associated with obstructive sleep apnoea in children is

Answer 1

Hypoplastic mandible (micrognathia) – difficult intubation § Pierre Robin sequence § Treacher Collins § Hemifacial microsomia (Goldenhar syndrome) Midface hypoplasia – difficult bag-mask ventilation § Apert syndrome § Crouzon syndrome § Pfeiffer syndrome § Saethre-Chotzen syndrome Macroglossia – difficult bag-mask ventilation AND difficult intubation § Hurler’s/Hunter’s syndrome (mucopolysaccharidoses) § Beckwith-Wiedemann syndrome § Down’s syndrome https://www.frca.co.uk/Documents/250%20The%20Difficult%20Paediatric%20Ai Mucopolysaccharidoses, Down syndrome, muscular dystrophies, and other neurologic disorders have been associated with obstructive sleep apnea Prevalence of OSAS. Genetic Disorder Prevalence of OSAS Neuromuscular diseases 69.2% Prader–Willi syndrome 94.7% Arnold–Chiari syndrome 80% Achondroplasia 100% Crouzon syndrome 100% https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156845/ | https://www.frca.co.uk/Documents/250%20The%20Difficult%20Paediatric%20Ai

Answer 2

Acromegaly IGF-2 is consistently elevated GH should be suppressed by glucose load in healthy pt. The continued elevation of GH despite glucose is suggestive of acromegaly

Answer 3

b) Diaphragm

Answer 4

b) Myasthenia Gravis

Answer 5

d. Ferritin ANZCA blue book: ACD caused primarily by inflammation Mechanism: 1. Iron - Inflammation reduces Iron availabilty as a protective mechanism whereby Iron is sequestered and stored in macrophages to limit availability to microbial pathogens - Hepcidin expression is increased, this prevents the release of Iron by reticuloendothelial system resulting in "functional iron deficiency" with reduced tissue availability of iron, despite apparently normal total body iron stores. (hence increased Ferritin) 2. Response to erythropoietin - mechanism not clear suspect blunting of response to erythropoietin 3. Therapeutic agents chemotherapies that impair bone marrow response to erythropoiesis 65% of patients with lung and gynae cancer treated with platinum based drug develop anaemia RCPA advice on interpretation of Soluble Transferrin Receptor: Soluble transferrin receptor levels in plasma are elevated if there is increased iron demand due to Iron deficiency, increased erythropoiesis (eg, Haemolysis) or dyserythropoiesis (eg, Megaloblastic anaemia), regardless of other, coexistent states. Thus, it can be used to demonstrate iron deficiency in patients who also have an acute phase response and it can distinguish Iron deficiency from the Anaemia of chronic disease. Patients with an acute phase response have reduced plasma iron and transferrin with elevation of Ferritin, making these usual indicators unreliable.

Answer 6

b. Myaesthenia gravis | ED95 is 0.8mg/kg in a MG patient

Answer 7

B Morphine Histamine-releasing

Answer 8

b) flaccid paralysis Guillain–Barré syndrome (GBS) is an inflammatory disease of the PNS and is the most common cause of acute flaccid paralysis

Answer 9

multiple sclerosis. https://academic.oup.com/bjaed/article/11/4/119/266998 Anaesthetic considerations. - Local anaesthetics may exacerbate symptoms due to the increased sensitivity of demyelinated axons to local anaesthetic toxicity. - Non-depolarizing neuromuscular blocking agents may be used in normal doses. Caution should be exercised when using depolarizing neuromuscular blocking agents if the patient is debilitated. - Temperature maintenance is important as symptoms can deteriorate with an increase in temperature, as demyelinated axons are also more sensitive to heat.

Answer 10

a) 100-200 2012 BERLIN DEFINITION OF ARDS ARDS is an acute diffuse, inflammatory lung injury, leading to increased pulmonary vascular permeability, increased lung weight, and loss of aerated lung tissue…[with] hypoxemia and bilateral radiographic opacities, associated with increased venous admixture, increased physiological dead space and decreased lung compliance. Key components - acute, meaning onset over 1 week or less - bilateral opacities consistent with pulmonary edema must be present and may be detected on CT or chest radiograph - PF ratio <300mmHg with a minimum of 5 cmH20 PEEP (or CPAP) - “must not be fully explained by cardiac failure or fluid overload,” in the physician’s best estimation using available information — an “objective assessment“ (e.g. echocardiogram) should be performed in most cases if there is no clear cause such as trauma or sepsis. Severity - ARDS is categorized as being mild, moderate, or severe:

Answer 11

Phenoxybenzamine UpToDate Phenoxybenzamine is the preferred drug for preoperative preparation to control blood pressure and arrhythmia in most centers in the United States. It is an irreversible, long-acting, nonspecific alpha-adrenergic blocking agent. With their more favorable side-effect profiles and lower financial cost, selective alpha-1-adrenergic blocking agents (eg, prazosin, t erazosin, or d oxazosin) are utilized in many centers or are preferred to phenoxybenzamine when long-term pharmacologic treatment is indicated (eg, for metastatic pheochromocytoma).

Answer 12

a) Closing capacity see graph in Millers

Answer 13

a) Variable intra-thoracic obstruction Dynamic (or variable, nonfixed) intrathoracic obstruction: flow limitation and flattening are noted on the expiratory limb of the loop.

Answer 14

a) Normal lungs M-mode image demonstrating seashore sign seen with normal lung sliding.

Answer 15

b) severe dermatographia

Answer 16

b) severe dermatographia

Answer 17

E. distance from anterior surface of dens to posterior surface of anterior arch of atlas The atlantodental interval is used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis. The anterior atlantodental interval is the horizontal distance between the posterior cortex of the anterior arch of the atlas (C1) and the anterior cortex of the dens in the median (midsagittal) plane Normal values for anterior atlantodental interval are: radiographs: adults: males: <3 mm females: <2.5 mm 1 (although most authors describe <3 mm ref) children: <5 mm ref CT: adults: <2 mm

Answer 18

decreased SVR Hyperthyroidism causes a hyperdynamic circulation, characterized by increased cardiac contractility and heart rate, increased preload, and decreased systemic vascular resistance (SVR), resulting in significantly increased cardiac output https://www.sciencedirect.com/science/article/pii/S0735109718333795#:~:text=Hyperthyroidism%20causes%20a%20hyperdynamic%20circulation,in%20significantly%20increased%20cardiac%20output.

Answer 19

Anaemia of chronic inflamation with iron deficiciency

Answer 20

b. Octreotide 50mcg bolus Vasoactive hormone release intra-operatively is best treated with intravenous boluses of 20–50 µg of octreotide, titrated to haemodynamic response. Vasopressin as an alternative vasoconstrictor that may be useful if prolonged vasoconstriction is required; however, the evidence base is small. It must be borne in mind that concomitant fluid losses, especially bleeding, may be responsible for intra-operative instability rather than hormone excess and that fluid resuscitation may be the answer rather than further octreotide therapy https://academic.oup.com/bjaed/article/11/1/9/285683

Answer 21

CP b. Cerebral palsy ->sux and volatiles are not contraindicated -> presence of extrajunctional receptors may cause hyperkalaemia a. Becker muscular dystrophy -> essentially milder Duchenne's (see duchenne response to Sux) b. Cerebral palsy -> Sux and volatiles not contraindicated -> reduced MAC requirement -> increased sensitivity to muscle relaxants c. Guillain Barre -> sux contraindicated due to risk of hyperkalaemia -> increased sensitivity to Non depolarising NB d. Frederich’s ataxia -> sux should be avoided due to risk of hyperkalaemia e. Duchenne muscular dystrophy -> sux and volatiles contraindicated due to rick of hyperkalaemia and rhabdomyolysis

Answer 22

d) myasthenia gravis In contrast to other neuromuscular disorders, succinylcholine may be used in myasthenia gravis. The required dose may need to be increased by up to two-fold, as those with the disease show a relative resistance to the drug. Sux is not recommended in patients with neuromuscular disease due to: 1. presence of extrajunctional receptors and risk of hyperkalaemia and rhabodmyolysis 2. fasiculations causing temperomandibular muscle spasm preventing intubation Suxamethonium is contraindicated in patients with recent burns or spinal cord trauma causing paraplegia (can be given immediately after the injury, but should be avoided from approximately day 10 to day 100 after the injury), | ED95 is 0.8mg/kg in a MG patient

Answer 23

) Hypertension Talley & O'Connor CVS Exam: S3: Physiological in pregnancy; sign of LV failure; AR & MR S4: Never physiological, most often due to systemic hypertension Atrial gallop - stiff LV - hypertrophy or ischaemic ventricle Source CV phys

Answer 24

d) SpO2 88–92% oxygen administration/ low fio2 assumed bleomycin Bleomycin Bleomycin is a particularly important chemotherapy drug for the anaesthetist to be aware of. Bleomycin is often used to treat germ cell tumours and Hodgkin's disease in a curative setting. The major limitation of bleomycin therapy is the potential for subacute pulmonary damage that can progress to life-threatening pulmonary fibrosis. Pulmonary toxicity occurs in 6–10% patients and can be fatal.2 Exposure to high-inspired concentration oxygen therapy, even for short periods, as experienced during anaesthesia, is often implicated in causing rapidly progressive pulmonary toxicity in patients previously treated with bleomycin.3 These claims have been considered controversial by some, but it is the authors' recommendation that any patient previously exposed to bleomycin therapy should be treated as high risk, and summary guidance regarding oxygen therapy is shown in Table 4. Summary guidance—oxygen therapy for patients who have received bleomycin > Patients have a life-long risk of bleomycin-induced lung injury > Oxygen therapy should be avoided if at all possible > Clinical procedures (and leisure activities) involving a high should be avoided If a patient is hypoxic > O2 therapy should be minimized to maintain O2 saturation of 88–92% > High oxygen concentrations should be used with extreme caution for immediate life-saving indications only (to maintain O2 saturation of 88–92%)

Answer 25

ALTERED 22.1 QUESTION D Spirometry FEV1 only GOLD 1 > 80% Pred GOLD 2 50-79% Pred GOLD 3 30-49% Pred GOLD 4 < 30% Pred

Answer 26

increased incidence of major bleeding

Answer 27

c) Lowest FiO2 possible Bleomycin Bleomycin is a particularly important chemotherapy drug for the anaesthetist to be aware of. Bleomycin is often used to treat germ cell tumours and Hodgkin's disease in a curative setting. The major limitation of bleomycin therapy is the potential for subacute pulmonary damage that can progress to life-threatening pulmonary fibrosis. Pulmonary toxicity occurs in 6–10% patients and can be fatal. Exposure to high-inspired concentration oxygen therapy, even for short periods, as experienced during anaesthesia, is often implicated in causing rapidly progressive pulmonary toxicity in patients previously treated with bleomycin. These claims have been considered controversial by some, but it is the authors' recommendation that any patient previously exposed to bleomycin therapy should be treated as high risk, and summary guidance regarding oxygen therapy is shown:

Answer 28

c) Prothrombinex | Has factors 2, 9, 10, heparin, ATIII

Answer 29

Chronic obstructive pulmonary disease (COPD) is the most common cause of cor pulmonale leads to an increase in RV afterload secondary to changes in pulmonary vascular structure and mechanics, and lung hyperinflation. Patients with COPD who subsequently develop RV dysfunction have an increased risk of admission to hospital and mortality

Answer 30

b. Procainamide BJA: Perioperative cardiac arrhythmias https://academic.oup.com/bja/article/93/1/86/265716 - Paroxysmal SVT (PSVT) due to re‐entrant circuits that involve accessory pathways (congenital electrical connections between the atrium and ventricle that bypass the AV node, such as Wolff–Parkinson–White Syndrome) pose caveats in the management of SVT. - It should be noted that patients with accessory pathways, in addition to PSVT, may also develop atrial fibrillation, and in the latter situation are at increased risk for developing ventricular fibrillation (VF) upon exposure to classic AV‐nodal blocking agents (digoxin, calcium channel blockers, beta blockers, adenosine) because these agents reduce the accessory bundle refractory period. - In such cases, i.v. procainamide, which slows conduction over the accessory bundle, is an acceptable option. Flecainide and amiodarone should also be considered, and cardiology consultation may be helpful.2

Answer 31

c. Low potassium diet (high K diet - dec HTN)

Answer 32

d) TXA VWD Types: 1 - quantitative - minor effect on bleeding - DDAVP useful 2 - qualitative - spectrum of effects on bleeding - (2a,2b,2m,2n) - DDAVP may be useful in consult with haem 3 - absence - major bleeding - no effect of DDAVP factors not recommended in Type 1 TXA and DDAVP are recommended but DDAVP not in list TXA 10mg/kg IV q8h DDAVP 300mcg intranasal 90-120 mins preop (DDAVP increases factor VIII levels 2-5x via release of VWF which binds VIII and prevents its clearance) Treatment of bleeding in an individual with von Willebrand disease (VWD) depends on: 1. Severity of bleeding 2, Site of bleeding 3. the type of VWD 4. the previous responses to therapy. The two main approaches: 1. Increasing the level of normal von Willebrand factor (VWF) activity via DDAVP 2. Replacing the defective VWF with VWF concentrates VWF concentrates have been demonstrated to provide excellent to good hemostasis in a number of patient populations and a number of bleeding types. DDAVP is only effective in some individuals, produces a smaller increase in VWF activity, and has a later onset and shorter duration of action.

Answer 33

b) Aortic Stenosis

Answer 34

d) Trendelenberg c) Supine Moving from upright to supine affects the respiratory function of the tetraplegic and high paraplegic individual differently to the able-bodied person. The increase in abdominal girth when sitting in tetraplegia is secondary to decreased abdominal muscle strength and the associated increased abdominal wall compliance. In the seated position, the abdominal contents are less supported by the decreased abdominal wall muscle tone and fall forward, increasing the waist size and lowering the diaphragm. In able-bodied subjects, the FVC is reduced in the supine position, whereas in tetraplegia it is increased. Postural changes are associated with symptoms; patients with an acute, high SCI report less breathlessness when supine compared to sitting. In the supine position, the weight of the abdominal contents forces the diaphragm to a higher resting level so that contraction produces greater absolute excursion of the diaphragm; an effect that can be increased when the person with tetraplegia is tipped 15° head down from supine such that the vital capacity rises by a further 6%

Answer 35

e) Normal Normal flow-volume loop: the expiratory portion of the flow-volume curve is characterized by a rapid rise to the peak flow rate, followed by a nearly linear fall in flow. The inspiratory curve is a relatively symmetrical, saddle-shaped curve.

Answer 36

c) Lung protective ventilation A congenital diaphragmatic hernia (CDH) occurs when a defect in the diaphragm allows abdominal organs to protrude into the thoracic cavity (Fig. 1). It affects approximately 1 in 3600 registered births and is a potentially life-threatening condition, the severity of which is primarily related to the extent of lung hypoplasia and pulmonary hypertension. Advances in management strategies include protective ventilation, careful timing of surgery, the judicious use of extracorporeal membrane oxygenation (ECMO) and the introduction of both thoracoscopic and fetal intervention, but it remains a challenging condition to treat successfully with overall mortality rates still around 30% A validated scoring system has been proposed based on various measurements, including: (i) birth weight <1.5 kg, (ii) Apgar score at 5 mins <7, (iii) presence of chromosomal abnormality, (iv) presence of major cardiac abnormality, and (v) suprasystemic pulmonary hypertension on echocardiography. This scoring system enables patients to be stratified into low (<10%), intermediate (∼25%) or high risk (∼50%) mortality groups. Cardiac defects have been shown to worsen outcome regardless of the severity of the hernia The presence of a small contralateral lung or a bilateral CDH are also poor prognostic signs. Ventilation Historically, aggressive ventilation was used to induce hypocapnia and alkalosis and thereby reduce pulmonary hypertension; however, protective ventilation strategies that avoid further injury to damaged lung tissue have reduced mortality in CDH. The CDH EURO Consortium advocates aiming for the limitation of peak inspiratory pressures to 25 cm H2O with PEEP kept at 3–5 cm H2O and allowing permissive hypercapnia. High-frequency oscillatory ventilation High frequency oscillatory ventilation (HFOV) is classically used as a rescue strategy when hypoxia and severe hypercapnia persist despite maximal conventional ventilation. The VICI trial (2016) randomised 171 neonates to conventional ventilation or HFOV as the initial mode of ventilation and found no significant difference in mortality, but those who had conventional ventilation were ventilated for shorter periods, needed less nitric oxide, sildenafil and ECMO, and had lower requirements for inotropic drugs. Timing of surgery Historically, CDH repair was treated as a surgical emergency. However, the degree of pulmonary hypoplasia is the major influence on prognosis and emergency surgery therefore confers little benefit. There is much debate but little consensus within the literature regarding the optimal timing of surgery. Recommendations from the CDH EURO Consortium state that the following physiological parameters should be met before surgery: (i) mean arterial pressure normal for gestation, (ii) preductal oxygen saturation consistently 85–95% on FiO2 <0.5, (iii) lactate below 3 mmol litre−1, and (iv) urine output more than 1 ml kg−1 h−1 12 These recommendations do, however, acknowledge that repair on ECMO is a viable treatment strategy in the context of appropriate patient selection. Little evidence Thorascopic approach has improved mortality compared to open approach BJA Education Article - Anaesthetic management of patients with a congenital diaphragmatic hernia https://www.bjaed.org/article/S2058-5349(18)30013-1/fulltext

Answer 37

3b Category GFR ml/min/1.73 m2 Terms G1 ≥90 Normal or high G2 60-89 Mildly decreased* G3a 45-59 Mildly to moderately decreased G3b 30-44 Moderately to severely decreased G4 15-29 Severely decreased G5 <15 Kidney failure Assign Albuminuria category as follows: Albuminuria categories in CKD Category ACR (mg/g) Terms A1 <30 Normal to mildly increased A2 30-300 Moderately increased* A3 >300 Severely increased** Abbreviations: ACR, albumin-to-creatinine ratio; CKD, chronic kidney disease. *Relative to young adult level. **Including nephrotic syndrome (albumin excretion ACR >2220 mg/g) **Collectively referred to as “CGA Staging”

Answer 38

d) Sarcoidosis Pulmonary hypertension: Normal spirometry + low DLCO Asthma: obstructive pattern and normal DLCO Obesity: restrictive pattern and normal DLCO Sarcoid: restrictive pattern and low DLCO

Answer 39

c Haemophilia b

Answer 40

e) 100mg hydrocortisone IV > note: alternatively, 6-8mg dexamethasone IV would suffice

Answer 41

d) myasthenia gravis or d) Cerebral palsy ->sux and volatiles are not contraindicated -> presence of extrajunctional receptors may cause hyperkalaemia if responses remembered incorrectly but of this list CP is probably the answer a. Becker muscular dystrophy -> essentially milder Duchenne's (see duchenne response to Sux) b. Cerebral palsy -> Sux and volatiles not contraindicated -> reduced MAC requirement -> increased sensitivity to muscle relaxants c. Guillain Barre -> sux contraindicated due to risk of hyperkalaemia -> increased sensitivity to Non depolarising NB d. Frederich’s ataxia -> sux should be avoided due to risk of hyperkalaemia e. Duchenne muscular dystrophy -> sux and volatiles contraindicated due to rick of hyperkalaemia and rhabdomyolysis In contrast to other neuromuscular disorders, succinylcholine may be used in myasthenia gravis. The required dose may need to be increased by up to two-fold, as those with the disease show a relative resistance to the drug. Sux is not recommended in patients with neuromuscular disease due to: 1. presence of extrajunctional receptors and risk of hyperkalaemia and rhabodmyolysis 2. fasiculations causing temperomandibular muscle spasm preventing intubation REPEAT

Answer 42

Raised ICP *also associated with a difficult airway (Difficult BMV Ventilation) Apert syndrome: Autosomal dominant abnormality of first branchial arch causing premature closure of cranial sutures, midface hypoplasia, choanal atresia, cleft palate, fusion of cervical spine (mainly C5-C6) and syndactyly. May have associated cardiac and renal abnormalities as well as intellectual impairment due to megalocephaly, hypoplasia of white matter and agenesis of the corpus callosum. Obstructive sleep apnea is present in 50% and there may be an increased incidence of upper airway obstruction at induction, which is mostly overcome by routine maneuvers. Classically, craniosynostosis release with fronto-orbital advancement is completed at 6 to 12 months of age if intracranial pressure (ICP) is normal [24-26]. However, elevated ICP may occur in up to 43 percent of cases. In this event, prompt surgical advancement and potentially ventriculoperitoneal shunt placement is required

Answer 43

d) Alprostadil https://www.rch.org.au/piper/neonatal_medication_guidelines/Alprostadil_(Prostin_VR)_%E2%80%93_(Prostaglandin_E1)/ Alprostadil (PROSTAGLANDIN E1) is a synthetic prostaglandin used to relax the ductus arteriosus in early post-natal life, where a patent ductus is critical for survival, including Tetralogy of Fallot, pulmonary atresia, pulmonary stenosis, tricuspid atresia and transposition of the great arteries. Dose To open a closed ductus arteriosus: 0.1 micrograms/kg/minute (100 nanograms/kg/min). An effect is usually seen within 30-60 minutes. Reduce the dose once an effect is seen or as directed by a Consultant.1 Doses > 0.1 micrograms/kg/minute are rarely more effective and may cause serious adverse effects.3 To maintain patency of ductus arteriosus: 0.01 to 0.02 micrograms/kg/minute (10-20 nanograms/kg/min).1, 2 For persistent pulmonary hypertension of the newborn (PPHN): 0.01 to 0.05 micrograms/kg/minute (10-50 nanograms/kg/min).2

Answer 44

a. Lupus anticoagulant Factor VII -> prolonged PT but not APTT Cold Agglutinins -> prolonged PT and APTT -> "sole abnormality" Haemophilia A -> isolated prolonged APTT -> associated with bleeding and not clotting Lupus Anticoagulation -> increased risk of clotting -> prolonged APTT and normal PT

Answer 45

e. Obstructive w/ reduced FEV1 Mucous narrowing airways = obstructive Parenchymal damage = restrictive Obstructive PFP remains the most common pulmonary function pattern in adult CF and is associated with -decrease FEV1 & FVC/FEV1 For patients with CF, an obstructive pattern is generally seen, with a decrease in forced expiratory volume in 1 s (FEV1), and forced vital capacity (FVC) to FEV1 ratio. https://academic.oup.com/bjaed/article/11/6/204/263786

Answer 46

d) pregnancy A third heart sound reflects rapid left ventricular distention along with an increased atrioventricular flow Heard in Congestive heart failure Associated with Dilated Cardiomyopathy with dilated ventricles Less commonly valvular regurgitation and left to right shunts May be normal physiological finding in patients less than 40yrs old

Answer 47

PCA e) Posterior cerebral ischaemia UTD: Postoperative visual loss after anaesthesia for nonocular surgery Pupillary light reflexes* Unilateral central retinal artery occlusion, ischemic optic neuropathy, and retrobulbar hematoma result in a poor or absent pupillary response to light ("direct" response) with a normal response when light is directed to the other pupil ("indirect" response); this "relative afferent pupillary defect" is revealed when tested with the swinging flashlight maneuver; if these processes are bilateral, there will be poor or absent direct pupillary responses and a relative afferent pupillary defect only if asymmetric. Mid-dilated and nonreactive pupils are consistent with acute angle-closure glaucoma, while sluggish to fixed and dilated pupils are seen with glycine-induced visual loss. Pupillary light reflexes are normal in cases of corneal abrasion, cerebral or cortical visual loss, and in cases of PRES. Examination of pupils is discussed more fully separately.

Answer 48

c. 50% 0.25mg/kg (Half) Source: PolioSA And ANZCA bulletin 2015 ‘Anaesthetists need to be wary of post polio syndrome’ -“twice as sensitive to non-depolarising muscle relaxants”

Answer 49

Repeat d) Sarcoidosis Normal FEV1/FVC ratio = no obstruction Low FVC = restrictive pattern Low DLCO = interstitial lung disease Asthma and emphysema would have obstructive pattern. Myasthenia gravis would have normal DLCO Pulmonary HTN would have normal spirometry and low DLCO.

Answer 50

b. von willebrand's disease - autosomal dominant inheritance - may have normal or prolonged APTT, PT is normal *Haem A: X-linked recessive disorder; would expect prolonged aPTT, and normal PT *Haem B: X-linked recessive disorder; would expect normal aPTT and normal PT REPEAT | vWD can have prolonged APTT or normal APTT. Haemophilias are X-linked

Answer 51

b. high HDL-C ## Footnote https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.105.169405

Answer 52

c) FEV1 43% In pulmonary function testing, a post-bronchodilator FEV1/FVC ratio of <0.70 is commonly considered diagnostic for COPD. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) system categorises airflow limitation into stages. In patients with FEV1/FVC <0.70: GOLD 1 - mild: FEV1 ≥80% predicted GOLD 2 - moderate: 50% ≤ FEV1 <80% predicted GOLD 3 - severe: 30% ≤ FEV1 <50% predicted GOLD 4 - very severe: FEV1 <30% predicted.

Answer 53

b) Alcoholic liver disease - AST>ALT In hepatitis and paracetamol toxicity would expect ALT>AST. In cholecystitis, would expect a cholestatic picture with raised conjugated bilirubin and raised GGT/ALP. LITFL: Overall analysis of Liver Function Tests (LFT) Transaminitis: Aminotransferases (AST, ALT) - Generally associated with hepatocellular damage - Generally not associated with cholestasis Ratio of AST and ALT can be useful in differential ALT is more specific for liver damage than AST AST: ALT =1 -> Associated with ischaemia (CCF and ischaemic necrosis and hepatitis) AST: ALT >2.5 -> Associated with Alcoholic hepatitis -> Alcohol induced deficiency of pyridoxal phosphate AST: ALT <1 -> High rise in ALT specific for Hepatocellular damage -> Paracetamol OD with hepatocellular necrosis -> Viral hepatitis, ischaemic necrosis, toxic hepatitis -> Elevation with cholestasis (ALP, GGT) ALP – primarily associated with cholestasis and malignant hepatic infiltration Marker of rapid bone turnover and extensive bony metastasis GGT – sensitive to alcohol ingestion Marker of hepatocellular damage but non-specific Sharpest rise associated with biliary and hepatic obstruction

Answer 54

c) Decreased clearance – same dose

Answer 55

a) Alprostadil Prostin (PGE1)

Answer 56

Intellectual impairment No solid refs

Answer 57

a) DDAVP Polyuria Low urine osm High serum osm High Na post transsphenoidal sx = Central DI

Answer 58

A A - Alcohol is a common cause of macrocytosis and macrocytic anemia. (UpToDate) B - No - normally normocytic chronic disease anaemia C - No - microcytic D - I can't find anything on macrocytosis with thyrotoxicosis, but hypothyroidism definitely does E - Possibly.... https://hemonc.mhmedical.com/content.aspx?bookid=1783§ionid=121720217

Answer 59

Hereditary spherocytosis. Auto-haemolytic, intraplenic haemolysis. High reticulocyte count (6-20%) (normal range 0.5-2%)

Answer 60

Uncertain SIADH: 1. hypotonic hyponatraemia 2. urine osmolality > plasma osmolality (<275mOsm/kg) (i.e. concentrated urine despite hypotonic blood) 3. urinary Na+ > 20mmol/L 4. normal renal, hepatic, cardiac, pituitary, adrenal and thyroid function 5. euvolaemia (absence of hypotension, hypovolaemia, and oedema) 6. correction by water restriction Addison's Hypo natraemia HYPER kalaemia Hypo glycaemia Acidosis Diuretics Hypo natraemia Hypo kalaemia High urinary Na and K https://www.derangedphysiology.com/files/Electrolyte%20Disturbance.pdf JAMA article on hyponatraemia https://emergencymed.org.il/wp-content/uploads/2022/08/jama_adrogu_2022_rv_220011_1657919726.49616.pdf

Answer 61

e) sinus tachycardia https://academic.oup.com/bjaed/article/9/2/61/299563 Typically anorexic patients are hypotensive and bradycardic. Bradycardia reflects the decrease in basal metabolic rate that arises as an adaptive response to starvation Electrocardiographic abnormalities are common and may be found in >80% of strict dieters. These include: 1. atrioventricular block 2. ST depression 3. T wave inversion 4. QT prolongation.

Answer 62

E. 100 mcg/L ?? < 30mcg/L < 100mcg/L IF CRP > 5 and/or Transferrin saturation < 20 https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/anae.13773#:~:text=Recommendations%20for%20best%20clinical%20practice,-Physicians%20should%20consider&text=The%20presence%20of%20anaemia%20should,identification%20of%20absolute%20iron%20deficiency.

Answer 63

TXA DDAVP for T1 Factor 8 for T2/3 or unresponsive DDAVP (RCH Guidelines)

Answer 64

Tracheal stenosis

Answer 65

a) neostigmine infusion Consider this Ogilve's Syndrome Psuedo-obstruction. If > 9cm dilation, would need surgical management. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3168359/#!po=17.5000

Answer 66

a. Diclofenac LIthium perioperative concerns: - Prolongation of NMB - Reduction in anaesthetic agent requirement - Avoid NSAIDs - No withdrawl symptoms - Discontinue 24hrs before surgery NSAIDs differentially alter lithium concentrations by multiple mechanisms, and one of these is to reduce prostaglandin E2 BJA: perioperative advice for psychotropic drugs

Answer 67

D. Cerebral Abscess HBOT Indications: - Indications are related to need for enhanced Pressure or oOxygenation and treatment of infection: Pressure - air or gas embolism - Decompression sickness Oxygenation: - arterial insufficiencies (central retinal artery occlusion, enhancement of healing in wound problems) - Carbon monoxide poisoning - Compromised grafts and flaps - Acute traumatic ischaemia - Delayed radiation injuries - Sudden sensorineural hearing loss - Severe Anaemia - Thermal burns Infection: - Clostridium myonecrosis (gas gangrene) - Intracranial abscess - Necrotising soft tissue infections - Refractory osteomyelitis Absolute Contraindications to HBOT: - untreated PTx - Premature Infants - Bleomycin - Disulfiram (antabuse) - Cisplatin Relative contraindications: - Pregnancy - Asthma - Thoracic Surgery - Emphysema with CO2 retention - upper respiratory tract infections - History of middle ear surgery or disorder - History of seizures - Fevers - Congenital spherocytosis - Optic neuritis

Answer 68

a. Cerebral oedema Cerebral Oedema Source: UpToDate

Answer 69

Life threatening organ dysfunction caused by a dysregulated host response to infection

Answer 70

Category GFR ml/min/1.73 m2 Terms G1 ≥90 Normal or high G2 60-89 Mildly decreased* G3a 45-59 Mildly to moderately decreased G3b 30-44 Moderately to severely decreased G4 15-29 Severely decreased G5 <15 Kidney failure Assign Albuminuria category as follows: Albuminuria categories in CKD Category ACR (mg/g) Terms A1 <30 Normal to mildly increased A2 30-300 Moderately increased* A3 >300 Severely increased** Abbreviations: ACR, albumin-to-creatinine ratio; CKD, chronic kidney disease. *Relative to young adult level. **Including nephrotic syndrome (albumin excretion ACR >2220 mg/g) **Collectively referred to as “CGA Staging” REPEAT

Answer 71

c) Lowest FiO2 possible oxygen administration/ low fio2 assumed bleomycin

Answer 72

d. Asthma What are the causes of an elevated DL CO ? The causes of an elevated DLCO are numerous, but is most commonly caused by asthma and obesity (increased pulmonary blood flow). Pulmonary hemorrhage is an additional important cause. https://www.atsjournals.org/doi/pdf/10.1513/AnnalsATS.201605-355CC

Answer 73

d) contraindicated as it won’t work Type 1: -Quantitative defect of VWF Type 2: -Qualitative Defect of VWF -Type 2 subclassification depending on plt binding function, F8 binding capcacity, number of high molecular weight VWF multimers Type 3: - complete absence of VWF Treatment: - do not need blood components to control haemorrhage -F8 plasma concentration >100 for major surgery and >50 for minor surgery -DDAVP approved for use in Type 1, no use in type 3, discuss its use with haematology in type 2 due to its variable effect -DDAVP given atleast 90mins before operation -TXA may be useful -VWF/F8 concentrates indicated in severe cases, type 3 and qualitiative defects in VWF -Plt infusions should be considered in persistent bleeding -Cryo has an unpredictable effect, only used if other treatments have failed

Answer 74

b) Pulmonary hypertension Up to date: Overview of pulmonary function testing in adults Diffusing capacity — Measurement of the single-breath diffusing capacity for carbon monoxide (DLCO; also known as transfer factor or TLCO) is quick, safe, and useful in the evaluation of restrictive and obstructive lung disease, as well as pulmonary vascular disease. The technique and interpretation are discussed separately. In the setting of restrictive disease, the diffusing capacity helps distinguish between intrinsic lung disease, in which DLCO is usually reduced, and other causes of restriction, in which DLCO is usually normal. In the setting of obstructive disease, the DLCO helps distinguish between emphysema, in which it is usually reduced, and other causes of chronic airway obstruction, like asthma or chronic bronchitis, where it is usually normal. The DLCO is also used in the assessment of pulmonary vascular disease (eg, thromboembolic disease, pulmonary hypertension), which typically causes a reduction in DLCO in the absence of significant restriction or obstruction

Answer 75

anaemia Iron deficiency can be caused by depletion of total Iron stores or a chronic loss of blood. Metabolism of Iron is also influenced by disease states including inflammation and malignancy. Raised Iron stores and inflammation upregulate the production of HEPCIDIN, a hormone responsible for the inhibition of enteral Iron absorption HEPCIDIN degrades iton trans-membrane transporter ferroportin on duodenal enterocyte membranes. it also inhibits the transport of stored iron from hepatocytes and macrophages into plasma in a similar manner. Upregulation of HEPCIDIN can produce functional iron deficiency, lading to what has been tradionally known as the anaemia of chronic disease HEPCIDIN deficiency is the cause of iron overload in hereditary hemochromatosis, iron-loading anemias, and hepatitis C HEPCIDIN is suppressed in iron deficiency, allowing increased absorption of dietary iron and replenishment of iron stores. Increased erythropoietic activity also suppresses HEPCIDIN production. HEPCIDIN is decreased in iron deficiency anemia, hemolytic anemia, and anemias with ineffective erythropoiesis

Answer 76

Serotonin Syndrome Hyper reflexia Usually has hypertension and hyperthermia https://static1.squarespace.com/static/5e6d5df1ff954d5b7b139463/t/617242e2ab18df2dee31f417/1634878179720/ICU_one_pager_hyperthermic_toxidromes.png

Answer 77

b) Alcoholic liver disease A raised serum tryptase (hypertryptasemia) has numerous diagnostic uses. The main use is in the diagnosis of anaphylactic reactions; however, it does not distinguish between IgE-mediated versus non-IgE-mediated reactions. Tryptase is a serine protease primarily produced by MCs, and to a lesser extent by mature basophils and myeloid progenitors. (Eosinophils have myeloid progenitor) Elevated serum tryptase is an independent prognostic factor for progression to ESRF in patients treated with ACEi or ARB https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/j.1365-2044.2004.03757.x Systemic Anaphylaxis: levels peak at 15-120mins and with half life of 1.5-2.5hrs histamine levels peak at 5 mins and decrease to baseline within 15-30mins B-Tryptase testing can be performed on blood samples obtained 1-6hrs after onset Hihg tryptase concentration can be found 3 days after death from suspected anaphylaxis Other allergic conditions: Asthma In asthma, β-tryptase is usually overexpressed or released from mast cells prematurely. It causes a cascade of events such as airway inflammation and bronchoconstriction. A mutation of the β-tryptase gene causes the overexpression Sudden Infant Death Syndrome: Anaphylaxis has been suggested to be a cause of the sudden infant death syndrome (SIDS), although allergen sensitivity and mast cell activation have not been demonstrated. Elevated postmortem levels of β-tryptase in victims of SIDS have been reported. Amniotic Fluid Embolism: A case study of an autopsy-proven fatal case of amniotic fluid embolism reported a significantly elevated serum β-tryptase level, suggesting possible mast cell activation. However, there are other reported cases of amniotic fluid embolism diagnosed clinically whose tryptase levels were not elevated. Systemic Mastocytosis: Characterised by mast cell hyperplasia in bone marrow, skin, liver, spleen and gastrointestinal mucosa. A study of tryptase levels in patients with biopsy-proven mastocytosis reported concentrations of total tryptase > 20 ng.ml−1 and ratios of total tryptase to β-tryptase > 20, whereas normal patients had total tryptase levels < 14 ng.ml−1 MC activation Syndrome These heterogeneous conditions are often associated with biochemical evidence of MC activation, but total tryptase may be normal. Urticaria/Agioedema: Basal total serum tryptase tends to be higher in patients with chronic urticaria over atopic and non-atopic healthy controls, likely due to increased MC burden and/or greater release of tryptase per MC. Other studies have found tryptase ≥15 μg/L in 12% of patients with urticaria/angioedema without anaphylaxis Familial Hypertryptasaemia These patients have a baseline tryptase of >8 μg/L and commonly have complaints of arthralgias, gastroesophageal reflux disease, flushing, urticaria, hypermobility, postural orthostatic tachycardia syndrome, increased risk of anaphylaxis to stinging insects, and irritable bowel syndrome CKD and ESRF Tryptase may be raised in patients with chronic kidney disease (CKD), accounting for around 7% of all elevated tryptase samples in one laboratory’s retrospective review of elevated tryptases. It tends to be elevated with more severe CKD, correlating with other markers of CKD including creatinine and proteinuria Haematological conditions: Hypereosinophilic syndrome (HES) is a heterogeneous group of systemic diseases of unknown cause characterised by excessive eosinophils invading the heart, lungs, brain and nerves, causing organ damage Patients with HES and elevated serum tryptase levels were more likely to develop fibroproliferative end organ damage and had a shorter life expectancy. Myelodysplastic syndrome (MDS) is a large group of acquired neoplastic disorders of the bone marrow most common in the elderly and is caused by an abnormal differentiation and maturation of haemopoietic cells. Elevated levels of total tryptase (α-tryptase and β-tryptase) are found in a group of patients with MDS Parasitic infection MCs and tryptase play a significant role in parasitic infections [72], so it is of no surprise that serum tryptase can be elevated in these infections. Gausher's disease Rare genetic disorder caused by the deficiency of β-glucocerebrosidase, an enzyme for the catabolism of glucocerebroside, a component of cell membranes. A single case report exists of an 18-month-old boy who had an immediate hypersensitivity to imiglucerase enzyme replacement and an elevated baseline tryptase of 63.2 μg/L.

Answer 78

C) AMI The association between OSA and perioperative mortality is unclear [19], with various studies showing increased [12,23] or comparable [14] mortality. While decreased mortality [7,18,43] has been reported in retrospective studies, this may be due to unrecognized or undiagnosed OSA in the control or non-OSA groups, and/or the possibility that patients with diagnosed OSA received monitoring and treatment of their OSA. SOBA 2015: Severe OSA occurs in 10–20% of patients with BMI > 35 kg.m2 and is often undiagnosed. Overall, a diagnosis of OSA is associated with a greater than doubling of the incidence of postoperative desaturation, respiratory failure, postoperative cardiac events and ICU admission [16]. The presence of multiple and prolonged oxygen desaturations increases the sensitivity to opioid-induced respiratory depression [17]. However, if identified pre-operatively and treated appropriately with continuous positive airway pressure (CPAP), the risk of complications is much reduced [18]. Obesity has no influence on the rate of unanticipated admission, postoperative complications, readmission or other unplanned contact with health professionals after home discharge.

Answer 79

d) Danazol https://www.allergy.org.au/hp/papers/hereditary-angioedema Treatment options: Plasma derived C1-esterase inhibitor = Berinert/Cinryze, Androgens = Danazol B2 Bradykinin REceptor antagonist = Icatibant FFP. Danazol (an androgen) is recommended as first line PROPHYLAXIS for planned procedures (need to give for 5-10 days prior and 2-5 days post) For emergency or high risk procedures C1 esterase inhibitor concentrate (Berinert or Cinryze) is recommended - give 1 hour before procedure - more effective than danazol but more expensive Berinert: - 20units/kg IV over 10 min - Symptoms usually stabilise in 30 mins - 2nd dose uncommon, but may be given 30mins to 2hrs after 1st dose Icatibant: - 30mg slow subcut infusion in abdominal area Due to the risk of precipitating laryngeal oedema, oropharyngeal procedures should usually involve general anaesthesia with endotracheal intubation Short answer: - if you have days before surgery increase danazole, if complex surgery increase danazole and give C1Inh - If you have acute emergency surgery give C1Inh Concentrate (Berinert/Cinryze) before and after - if you have an acute attack use C1Inh or Bradykinin antagonist (Icatibant) - If C1 Inh and Bradykinin antagonoist are not available then use FFP but this may worsen the attack due to the presence of C4 in the FFP - Has Cetirizine been misremembered instead of Cinryze as an option in this question? No it wasn't -> adrenaline, steroids, antihistamines have no role in treatment of HAE acute attack

Answer 80

c. Hypocalcaemia Laryngospasm is a rare, but serious and potentially lethal, complication of hypocalcemia in adults. In every adult presenting with acute dyspnea and stridor, the possibility of hypocalcemia should be considered. Hypocalcemia should be treated promptly.

Answer 81

e. AAA Osteoarthritis nerve compression syndrome due to bony overgrowth, and carpal tunnel syndrome Hypertension Diabetes mellitus Cardiomyopathy/HF Colorectal cancer Sleep Apnea Thyroid nodules and thyroid cancer Hypogonadism Compression of the optic chiasm Source: BJA

Answer 82

d. Downs Syndrome

Answer 83

D. Amitriptyline Amitriptyline (used in low doses for 90 days from onset of the herpes zoster rash) reduces the incidence of postherpetic neuralgia N.B Antiviral agents started within 72 hours of onset of the herpes zoster rash accelerate the resolution of acute pain (U) (Level I) but **do not reduce** the incidence, severity and duration of postherpetic neuralgia UTD Both Gabapentinoids and TCAs are effective at TREATING postherpetic neuralgia. The former have lower risk of discontinuation due to adverse side effects. For moderate or severe pain, use gabapentinoids.

Answer 84

d) Pulmonary haemorrhage Rewording of 21.2 Question Won't increase in Myasthenia Gravis Causes of HIGH value include: Asthma Left-right intracardiac shunt polycythaemia Pulmonary haemorrhage Obesity - Dlco will increase but kco will not

Answer 85

Answers could also possibly be COPD, Acute stroke or Neonates c) Bleomycin toxicity Bleomycin is a particularly important chemotherapy drug for the anaesthetist to be aware of. Bleomycin is often used to treat germ cell tumours and Hodgkin's disease in a curative setting. The major limitation of bleomycin therapy is the potential for subacute pulmonary damage that can progress to life-threatening pulmonary fibrosis. Pulmonary toxicity occurs in 6–10% patients and can be fatal.2 Exposure to high-inspired concentration oxygen therapy, even for short periods, as experienced during anaesthesia, is often implicated in causing rapidly progressive pulmonary toxicity in patients previously treated with bleomycin.3 These claims have been considered controversial by some, but it is the authors' recommendation that any patient previously exposed to bleomycin therapy should be treated as high risk, and summary guidance regarding oxygen therapy is shown in Table 4. Summary guidance—oxygen therapy for patients who have received bleomycin > Patients have a life-long risk of bleomycin-induced lung injury > Oxygen therapy should be avoided if at all possible > Clinical procedures (and leisure activities) involving a high should be avoided If a patient is hypoxic > O2 therapy should be minimized to maintain O2 saturation of 88–92% > High oxygen concentrations should be used with extreme caution for immediate life-saving indications only (to maintain O2 saturation of 88–92%)

Answer 86

8mg/hr Guidelines for mx of glucocorticoids during the perioperative period for patients with adrenal insufficiency https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/anae.14963

Answer 87

e) Liver transplantation - Oxygen therapy for symptom relief - Liver transplant provides long term survival benefit - All other therapies tried but no conclusive evidence of benefit/nil are FDA approved Hepatopulmonary Syndrome Article https://www.ncbi.nlm.nih.gov/books/NBK562169/ Hepatopulmonary syndrome (BJA) - Prevalence up to 20% (end stage liver disease) - Characterised by: disordered pulmonary capillary vasodilation and VQ mismatch - Present with hypoxia, ortheodeoxia (decrease in PaO2 when standing) - Diagnosis w/bubble echocardiography - Risk factor for early post-transplant mortality - If transplant successful, will resolve over time

Answer 88

b) Hypoglycaemia Stoelting: Prader-Willi syndrome is a rare genetic disorder characterized by hypothalamic-pituitary abnormalities with severe hypotonia during the neonatal period and during the first two years of life, hyperphagia with a risk of morbid obesity during infancy and adulthood, learning difficulties and behavioural problems or severe psychiatric problems. The disease affects 1/25,000 births. https://www.orphananesthesia.eu/en/rare-diseases/published-guidelines/prader-willi-syndrome/1339-prader-willi-syndrome-2/file.html Prader-Willi syndrome is a rare genetic disorder characterized by hypothalamic-pituitary abnormalities with severe hypotonia during the neonatal period and during the first two years of life, hyperphagia with a risk of morbid obesity during infancy and adulthood, learning difficulties and behavioural problems or severe psychiatric problems. The disease affects 1/25,000 births.

Answer 89

Most likely answer will be related to hypophosphataemia Refeeding syndrome is a constellation of biochemical abnormalities which occurs when normal intake is resumed after a period of starvation. Its characteristic features are **low levels of phosphate, potassium, magnesium and sodium**. Its major complications include **cardiac arrhythmias, heart failure (due to hypophosphataemia), muscle weakness, rhabdomyolysis, seizures and an altered sensorium.** The major risk factors are calorie malnutrition of any cause, alcohol or drug use, low BMI (18-16) and starvation for 5-10 days. Pathophysiology With the restoration of glucose as a substrate, insulin levels rise and cause cellular uptake of these ions. **Depletion of adenosine triphosphate (ATP) and 2,3-diphosphoglyceric acid (2,3-DPG)** results in **tissue hypoxia** and **failure of cellular energy metabolism.** This may manifest as **cardiac and respiratory failure**, with **paraesthesiae** and **seizures** also reported. Thiamine deficiency may also play a part. - Exogenous sources of phosphate are inadequate to supplement the daily phosphate requirements - Intracellular phosphate stores are used to synthesise ATP (using protein and fat as fuel) - Homeostatic mechanisms maintain serum concentrations of these ions at the expense of intracellular stores Reference: https://derangedphysiology.com/main/required-reading/endocrinology-metabolism-and-nutrition/Chapter%20315/refeeding-syndrome "

Answer 90

serum free metanephrines and nor-metanephrines https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230088/ ## Footnote https://www1.racgp.org.au/ajgp/2021/january-february/adrenal-disease-an-update

Answer 91

Increased sensitivity to non depolarisers Ck -> Anaesthesia induced rhabdo Cardio- All at-risk females, regardless of their carrier status, should be monitored for development of cardiomyopathy

Answer 92

d) Flucloxacillin Need remembered options: Black box warning for fluoroquinolones (ciprofloxacin) Probably also avoid Aminoglycosides (Amikacins/gentamicin/streptomycin) and tobramycin although TOBRAMYCIN probably least problematic of these. Macrolides (erythromycin) These antibiotics have not been shown to cause many problems for MG patients Tetracycline (doxycycline, minocycline) – this may worsen MG Sulfonamides (Bactrim), Penicillin – causes rare cases, usually not a problem for majority of MG patients https://myastheniagravis.org/mg-and-drug-interactions/#:~:text=These%20antibiotics%20have%20black%20box,Ketek%20(telithromycin)

Answer 93

a) Low BSL, hyperkaelamia, hypernatraemia Adrenal crisis is a medical emergency and should be considered in any patient presenting with one or more of the following symptoms: * altered consciousness * circulatory collapse * hypoglycaemia * hyponatraemia * hyperkalaemia * seizures * history of steroid use/withdrawal * any clinical features of Addison disease Adrenal crisis may be precipitated by stress, sepsis, dehydration or trauma; clinical features may be modified accordingly. In patients with known adrenal insufficiency, nonadherence with therapy, inappropriate cortisol dose reduction or lack of stress related cortisol dose adjustment can cause adrenal crisis. Aus Family Physician - RACGP Re chat below - incorrect recall, have updated A Why A? All three should be seen - glucocorticoid deficiency causes low Na and glucose while simultaneous mineralocorticoid deficiency low K. Crisis typically presents with hypotension abdo pain, nausea, vomiting and confusion. No one electrolyte/lab value can tie all those together.

Answer 94

B. Aphasia ## Footnote UTD

Answer 95

Answer: c) MS CEACCP 2012 Neuromuscular disorders and anaesthesia. Part 2: specific neuromuscular disorders Multiple sclerosis This is the most frequently occurring demyelinating neuromuscular disorder. It is a chronic relapsing condition characterized by the formation of plaques within the brain and spinal cord. These plaques cause demyelination around the axons, resulting in weakness and spasticity as well as sensory dysfunction. Anaesthetic considerations. Local anaesthetics may exacerbate symptoms due to the increased sensitivity of demyelinated axons to local anaesthetic toxicity. Non-depolarizing neuromuscular blocking agents may be used in normal doses. Caution should be exercised when using depolar- izing neuromuscular blocking agents if the patient is debilitated. Temperature maintenance is important as symptoms can deteriorate with an increase in temperature, as demyelinated axons are also more sensitive to heat. BJA: Perioperative management of myasthenia gravis (2021 - written after this MCQ): Several factors, many associated with surgery and anaesthesia, may exacerbate myasthenia or lead to a myasthenic crisis, a life-threatening condition in which severe respiratory muscle insufficiency leads to respiratory failure. Crises are most commonly precipitated by infection. Other precipitants include surgery, residual neuromuscular block, pain, many drugs, hypo- and hyperthermia, reduction or withdrawal of treatment, pregnancy, stress and sleep deprivation.

Internal medicine Flashcards

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