MCQs Flashcards
- A 23-year-old male returns to Sydney after backpacking in South East Asia for the past three months. He travelled to Hong Kong, Thailand, Cambodia, Thailand, Laos, Indonesia and Singapore and returned two days ago. He presents with fever, rigors, abdominal pain, fatigue and headache. He denies any nausea, vomiting or diarrhoea. On examination he is febrile at 38.8 C, however his heart rate and blood pressure are within normal limits. His abdomen is soft but tender on deep palpation with scant bowel sounds. His examination is otherwise unremarkable with no organomegaly or rash.
Which investigation is the most useful in yielding the diagnosis?
a. Stool OCP and culture
b. Dengue serology
c. Blood culture
d. Blood thick and thin film
e. CT abdomen-pelvis
Answer: c
The most important diagnoses to exclude in returned travellers are malaria, dengue fever and typhoid fever. All three are possible differential diagnoses in this clinical scenario, however, the most likely diagnosis based on the available information is typhoid fever.
Typhoid (enteric) fever is caused by Salmonella ser. Typhi or Salmonella ser. Paratyphi, transmitted by the faecal oral route. It is diagnosed by isolation of the Salmonella ser., a gram-negative bacilli, on blood culture. Typhoid fever presents with persisting fever, abdominal pain, headache and relative bradycardia. Severe disease can cause CNS complications and bowel obstruction due to ileus. Salmonella ser. can be detected in stool, however, the patient is not reporting diarrhoea for a stool OCP and culture.
Malaria is a life threatening anthropod borne illness and is detected with a thick and thin film looking for the Plasmodium species in infected erythrocytes. In south-east Asia, Plasmodium falciparum and Plasmodium vivax are more common. A malaria immunochromatographic test is POC test also used in the diagnosis of malaria. It presents with fever, fatigue, myalgia, headache, abdominal pain, hepatosplenomegaly and haemolytic anaemia.
Dengue fever is another anthropod borne illness and presents with fever, arthralgia, rash, deranged liver function, thrombocytopenia and haemoconcentration. It is diagnosed with dengue serology and the NS1 antigen. Management is supportive and may require intensive care if complicated by haemorrhagic shock.
- A 25-year-old man with Crohn disease has begun receiving TPN. He has a history of colectomy, multiple small-bowel resections, and ileorectal anastomosis, with gradual loss of weight due to short bowel syndrome. He feels well. Laboratory tests 2 weeks after starting TPN show ALT 78 U/L, AST 59 U/L, and normal alkaline phosphatase, total bilirubin, creatinine, and complete blood cell count. The liver test abnormalities are new. Three weeks ago, before he began receiving TPN, he received 2 units of packed red blood cells. His wife has been diagnosed to have chronic hepatitis C.
Which of the following is most likely to account for these new liver test abnormalities?
a. TPN
b. Blood transfusions
c. Crohn disease
d. Primary sclerosing cholangitis
e. Acute hepatitis C
Answer: a
TPN and overfeeding may cause mildly elevated ALT and AST levels, which improve over time. Viral hepatitis from a blood transfusion is unlikely given the low risk of infected donor blood and the short interval (3 weeks) between transfusion and the ALT elevation. There is no reason why the patient’s Crohn disease would flare now, and he feels well. Patients who have primary sclerosing cholangitis usually present with cholestatic liver test abnormalities. Acute hepatitis C from sexual transmission from his wife is also unlikely
- Which of the following is considered as the hallmark of refeeding syndrome?
a. Hypokalemia
b. Hyperkalemia
c. Hypophosphatemia
d. Markedly elevated liver enzymes
e. Hypoglycemia
Answer: c Refeeding syndrome is the result of rapid fluid and electrolyte shifts during aggressive nutritional rehabilitation of malnourished patients. It can be potentially fatal if not diagnosed and treated early. Refeeding syndrome is marked by:
* Hypophosphatemia
* Hypokalemia
* Congestive heart failure
* Peripheral edema
* Rhabdomyolysis
* Seizures
* Hemolysis
* Respiratory insufficiency
Hypophosphatemia is the hallmark of the syndrome, and the risk is greatest in those who are severely malnourished. The phosphate stores are depleted in those with anorexia nervosa and starvation. When nutritional replenishment starts and patients are fed carbohydrates, glucose causes release of insulin, which triggers cellular uptake of phosphate (and potassium and magnesium) and a further decrease in serum phosphorous levels. Entry of glucose into cells starts the process of glycolysis, Krebs cycle and oxidative phosphorylation with the intention to form new ATPs- this leads to further depletion of existing phosphate. Mildly abnormal LFTs and hyperglycemia are commonly seen during the first few weeks of refeeding.
- A 25-year-old man recently received a diagnosis of ulcerative colitis. Colonoscopy at the time of diagnosis showed mildly active disease throughout the colon with no evidence of dysplasia or polypoid lesions. He began therapy with Mesalazine 2.4 g daily. Routine blood work shows an elevated alkaline phosphatase level. He undergoes magnetic resonance cholangiopancreatography and is given a diagnosis of primary sclerosing cholangitis (PSC). When should he undergo his next colonoscopy? a. In 8 years b. In 2 years c. In 6 months d. In 1 year e. In 5 years
Answer: d Although this patient has a recent diagnosis of ulcerative colitis, he also has PSC. The diagnosis of PSC significantly increases his risk of colorectal cancer as compared to someone who only has ulcerative colitis. All patients with IBD and PSC should undergo annual surveillance colonoscopy beginning at the time of the PSC diagnosis.
- A 26-year-old male presents ED with hypotension, swollen face and hands and difficulty breathing while playing tennis. He had a tomato sandwich and water right before he started playing and no other foods for the day. He is not on any medications, does not drink alcohol and has not been sick recently. He describes a history of intermittent urticaria previously when running. He improved rapidly with adrenaline and his tryptase level was noted to be elevated with a repeat level done in 24 hours returning to normal. He
Which one of the following is the most useful next line of investigation?
a. Specific IgE to alpha-gal
b. Specific IgE to omega-5 gliadin
c. Urine histamines
d. C-Kit mutation on peripheral blood
e. Total IgE levels
Answer: b
The clinical history is classical for wheat dependent-food dependent, exercise-induced anaphylaxis. Omega-5 gliadin, a protein in gluten has been identified as an important allergen in this disorder as well as in wheat allergy causing anaphylaxis independent of exercise.
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Specific IgE to alpha-gal is associated with mammalian meat allergy which is not consistent with clinical history. Urine histamine and c-Kit mutation maybe useful in setting of mastocytosis but his tryptase has gone back to normal. Total IgE is a marker of atopy and is not useful in this context.
- An 18-year-old women presents with a history of skin swelling, severe abdominal pain, nausea and vomiting since early childhood. The attack occurs at a monthly basis and resolves spontaneously over 2-5 days. She’s also experienced laryngeal swelling requiring intubation on several occasions. The episodes are largely unpredictable, and the patient’s mother and brother had similar but less frequent and milder attacks.
Which of the following statements is most likely to be false?
a. The disease is caused by a mutation in the SERPIN1 gene
b. C4 levels should be one of the first line investigations
c. Danazol is a treatment for the condition
d. The patient should be prescribed an Epi-Pen
e. C1inhibitor levels and function can be normal in this patient
Answer: d
All options are true other than d), angioedema is not responsive to adrenaline as it is bradykinin mediated. Hereditary angioedema is characterized by recurrent episodes of angioedema in the absence of urticaria or pruritus, and mostly affects the skin or mucosal tissues of the upper respiratory and gastrointestinal tracts. Although the swelling is self-limited and resolves in two to five days without treatment, laryngeal involvement may cause fatal asphyxiation. Pathogenesis of the commonest type (type 1) involves deficiency or dysfunction of C1 inhibitor (C1-INH). While C1-INH has a vital role in the inhibition of complement system, it also plays a role in limiting bradykinin production by inhibiting kallikrein, which is a precursor of bradykinin. Therefore, when C1-INH is deficient or dysfunctional, bradykinin production is high; bradykinin causes vasodilatation, increases capillary permeability and attracts leucocytes leading to the angioedema.
- Which of the following autoantigens is NOT associated with systemic lupus erythematosus?
a. Smith
b. RNP
c. dsDNA d. Ro52
e. Smooth muscle (F-Actin)
Answer: E
Smooth muscle antibody (F-Actin) is associated with type 1 autoimmune hepatitis. The rest of the antigens lead to the antibodies commonly seen in SLE.
As a reminder, anti-Smith(Sm) antibody has the highest specificity for lupus.
Following is the specificity and sensitivity of antibodies to “extractable nuclear antigens” (ENA) for the diagnosis of SLE:
* Anti-Ro (SS-A): sensitivity 61% and specificity 80-93%
* Anti-La (SS-B): sensitivity 27-35% and specificity 88-97%
* Anti-Sm: sensitivity 34-45 % and specificity 88-100 %
* Anti-RNP: sensitivity 39-64 % and specificity 84-97%
- Which of the following is not a contraindication to commercial air travel in the context of end of life?
a. Pneumothorax with persistent air leak
b. Bowel obstruction without a venting gastrostomy tube
c. Baseline oxygen requirement exceeds 4L/minute
d. Hypoxic challenge test with oxygen saturations (SpO2) of 86%
e. Unstable angina
Answer: d
This is usually asked in the context of patients wanting to:
* Take a last holiday.
* Fly home to die.
* Fly abroad for experimental or last-ditch treatment.
* Airlines request for correspondence.
Physiology:
* Commercial flight cabin pressurized to altitude of 8000 feet (about 15% oxygen at sea level).
* In healthy passengers, arterial O2 tension falls to about 53-64mmHg.
* Physiological response to acute hypoxaemia is mild-moderate hyperventilation.
* Expansion of gasses is about 30% (hence caution with recent intracranial or abdominal surgery, ear pathology or bowel obstructions).
Requirement for in-flight oxygen needs to be communicated to the airline in advance as processes can vary e.g., travel clearance forms. If commercial air travel is not possible, medical escort or charted flights may be an option – at a cost. Dying on board is a real risk.
- A 75-year-old man noted a lump close to his left nipple and underwent a mastectomy and sentinel lymph node biopsy. His report showed a node-negative, estrogen receptor (ER)-positive breast cancer. Genetic testing was positive for a deleterious germline BRCA2 mutation. What adjuvant therapy would be the best for recurrence risk reduction of breast cancer? a. Tamoxifen b. Enzalutamide c. Letrozole (AI) d. Olaparib (PARP inhibitor)
Answer: a Tamoxifen is the better agent for hormone receptor-positive male breast cancer. Enzalutamide is commonly used in prostate cancer, and its role in a certain type of breast cancer remains investigational. Olaparib is effective in metastatic HER2-negative breast cancer patients with germline BRCA mutations and has been used in various other breast cancer trials.
- The clinical definition of sepsis in hospitalised patients include all of the following except:
a. Systolic Blood Pressure of 100 mm Hg and below
b. Altered consciousness
c. Heart rate of 110 beats per minute
d. Respiratory rate of 22 per minute or higher
Answer: c The definitions of sepsis and septic shock have rapidly evolved since the last two decades.
The previous definitions of sepsis which were based on Systemic Inflammatory Response Syndrome (SIRS) did not promote the understanding of the sepsis process since it is not always caused by infection and so are not used now.
The clinical criteria to diagnose sepsis in hospitalised adults (that require prolonged ICU stay or high risk of death) at bedside include quick Sequential Organ Function Assessment (qSOFA); i.e. two or more of the
* Hypotension: SBP less than or equal to 100 mmHg
* Altered mental status (any GCS less than 15)
* Tachypnoea: RR greater than or equal to 22
- Non-invasive Ventilation is contra-indicated in the treatment of:
a. Untreated Pneumothorax
b. Cardiogenic Pulmonary Oedema
c. Exacerbation of Chronic Obstructive Pulmonary Disease (COPD)
d. Pulmonary infiltrates in an immunocompromised host
Answer: a
Non-invasive ventilation (NIV) is the application of ventilation via sealed face mask; and can be either Continuous Positive Airway pressure (CPAP) or Bilevel Positive Airway Pressure (BIPAP).
Established indications of NIV in hospitalised patients include:
* Exacerbations of COPD (decreases work of breathing, unloads respiratory muscles)
* Cardiogenic Pulmonary Oedema (alveolar recruitment, decreased preload and afterload)
* Prophylaxis of respiratory failure after extubation
* Treatment of respiratory failure caused by pulmonary infiltrates in an immunocompromised host
* Obstructive Sleep Apnoea (OSAS) / Obesity-induced hypoventilation syndrome (OHS)
* Post-traumatic Respiratory failure (rib fractures)
* Pre-oxygenation prior to intubation
* Post-operative Respiratory Failure (selected patients)
Contra-indications to NIV include:
* Cardiac & Respiratory Arrests
* Inability to protect airway – poor cough, excessive/ inability to clear secretions, decreased conscious state/ coma
* upper airway obstruction
* Untreated pneumothorax (risk of worsening)
* Marked haemodynamic instability (e.g. shock, ventricular dysrhythmias)
* Following upper GI surgery (debatable) and intractable vomiting
* Maxillofacial surgery & Nasal fractures
* Base of skull fracture (risk of pneumocephalus)
- The diagnostic criteria for Acute Respiratory Distress Syndrome (ARDS) does NOT include:
a. Acute Onset
b. Bilateral pulmonary infiltrates
c. Hypercapnoea
d. Exclusion of cardiac causes of pulmonary infiltrates
Answer: c
The Berlin Definition of ARDS (2012)* include:
* Acute Onset (one week or less)
* Bilateral pulmonary infiltrates consistent with pulmonary oedema
* Hypoxia (PaO2/FiO2 of less than 300 with a minimum of 5cm of PEEP)
* Must not be fully explained by cardiac failure or fluid overload; and objective assessment of cardiac function is usually warranted.
- An 18-year-old boy has been diagnosed with Staphylococcus aureus endocarditis affecting the mitral valve and complicated by septic cerebral embolism. Which of the following factors would prompt the need for urgent surgery (within days) following diagnosis?
a. Development of atrial fibrillation
b. Fungal cause of endocarditis
c. Vegetation size 12mm
d. Development of intracerebral haemorrhage
e. Development of delirium
Answer: c
This question tests the candidate’s knowledge on risk factors for early adverse outcomes in infective endocarditis and indications for the timing of surgical intervention in this population. Vegetation size > 10mm with an established embolic event is a prompt for the need for urgent surgery given high ongoing embolic risk.
Intracerebral haemorrhage indicates primary bleeding with or without concomitant ischemic stroke. Not surprisingly, the presence of intracerebral haemorrhage is correlated with a significantly higher risk of surgical mortality. Haemorrhagic strokes confer a worse prognosis, and some form of surgical delay is likely prudent, guided by serial neurological imaging.
Fungal infection is typically an indication for early elective surgery given difficulty in source control and infection clearance.
Please see available reading materials on indication and timing of surgical intervention in infective endocarditis.
- What is the primary advantage of drug-eluting stents when compared to bare metal stents in the treatment of ischaemic heart disease?
a. Reduction in all-cause mortality
b. Reduction in risk of early stent thrombosis
c. Reduction in risk of target vessel revascularisation
d. Reduction in risk of myocardial infarction
e. Need for only single antiplatelet therapy
Answer: c
This question assesses the candidate’s knowledge on the mechanism of action and benefits of diverse types of coronary stents. Percutaneous coronary intervention (PCI) is a minimally invasive nonsurgical procedure performed to improve blood flow in one or more segments of the coronary circulation. Coronary revascularization with PCI primarily involves the use of balloon angioplasty and intracoronary stenting with either drug-eluting stents or bare metal stents. Initial coronary stents were of the bare metal type, with newer generation drug eluting stents available with advances in technology. The benefit of drug eluting stents is with regards to a reduction in local neointimal hyperplasia and therefore risk of in-stent restenosis.
Along this vein, evidence from randomized trials and large PCI registry databases suggest that drug eluting stents significantly lower the rate of target lesion revascularization compared with bare metal stents. Target lesion revascularization is traditionally defined as either repeat percutaneous or surgical revascularization for a lesion anywhere within the stent or the 5-mm borders proximal or distal to the stent. With regard to safety, the preponderance of evidence suggests that current-generation drug eluting stents have similar rates of death and myocardial infarction compared to bare metal stents. Further, the risk of stent thrombosis with current-generation drug eluting stents is similar to or possibly lower than bare metal stents. Both stent types require an initial period of dual antiplatelet therapy, with drug eluting stents typically requiring a longer duration of continued dual anti-platelet therapy relative to bare metal stents. In patients with stable ischemic heart disease treated with DAPT after drug-eluting stent (DES) implantation, P2Y12 inhibitor therapy with clopidogrel should be given for at least 6 months (Class I). In patients with stable ischemic heart disease treated with DAPT after bare-metal stent (BMS)
implantation, P2Y12 inhibitor therapy (clopidogrel) should be given for a minimum of 1 month (Class I). In patients with acute coronary syndrome (ACS) (non-ST elevation [NSTE]-ACS or ST elevation myocardial infarction [STEMI]) treated with DAPT after BMS or DES implantation, P2Y12 inhibitor therapy (clopidogrel, prasugrel, or ticagrelor) should be given for at least 12 months (Class I). There are alterations in the recommendations dependent on the patient’s underlying ischaemic and bleeding risk. Further, use of bare metal stents is now becoming rarer given the efficacy of drug eluting stents. At present, bare metal stents are generally utilised in the following settings: - Patients in whom a DES cannot be implanted due to large vessel size (>5 mm). - Patients who cannot take 30 days of dual antiplatelet therapy, such as those requiring urgent surgery or have active bleeding. However, the evidence for safety of BMS or benefit over DES in these settings is lacking.
- Which of the following can be stopped abruptly with minimal risk of withdrawal?
a. Nebivolol
b. Diazepam
c. Sertraline
d. Methadone
e. Lercanidipine
Answer: e
A: incorrect. Withdrawal of beta-blocker therapy results in an increased sympathetic activity presumably from an increase in adrenergic receptors in response to the beta blockade. This can exacerbate ischaemic heart disease and precipitate a myocardial infarction. It can lead to ventricular tachyarrhythmias and lead to sudden cardiac arrest.
B: incorrect. Withdrawal of benzodiazepines results in a symptom of Psychosis, Seizures, Dysphoria, Perceptual disturbances, Anxiety, Tremors (PSDPAT)
C: incorrect. There is a discontinuation syndrome associated with an abrupt cessation of sertraline -including dysphoria, agitation, sensory disturbances (e.g. paraesthesia)
D: incorrect. Abrupt withdrawal of methadone can result in an opioid withdrawal syndrome. This includes flu-like symptoms (rhinorrhoea, piloerection), increased sympathetic activity (restlessness, low grade temperature, tremor, mydriasis, mild hypertension and tachycardia), gastrointestinal distress (e.g. abdominal cramps, diarrhoea, and vomiting), yawning
E: correct. Abrupt cessation of a dihydropyridine calcium channel blocker results in minimal side effects
