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Question 1
Incorrect
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A 35-year-old male presented to the ER after being rescued from a house fire. He complained of feeling dizzy and having a worsening headache. On examination, he was dyspnoeic, drowsy and confused. There was no evidence of facial burns and no stridor. He was normotensive, tachycardic (pulse rate: 102 bpm), tachypnoeic (respiratory rate: 35/min) and had O2 saturation of 100% in room air. His venous blood gas results are given below: pH - 7.28 pCO2 - 3.5 kPa pO2 - 15.9 kPa Na+ - 139 mmol/L, K+ - 4.5 mmol/L, Bicarbonate - 11 mmol/L, Chloride - 113 mmol/L, Lactate - 13.6 mmol/L, Keeping in mind the likely diagnosis, which among the following is the most appropriate intervention for this patient?
Your Answer: Intubate and ventilate
Correct Answer: Intravenous hydroxocobalamin
Explanation:The most appropriate intervention in this patient is intravenous hydroxocobalamin.
The clinical scenario provided is suggestive of acute cyanide toxicity secondary to burning plastics in the house fire.
Cyanide ions inhibit mitochondrial cytochrome oxidase, preventing aerobic respiration. This manifests in normal oxygen saturations, a high pO2 and flushing (or ‘brick red’ skin) brought on by the excess oxygenation of venous blood. In the question above it is important to note that the blood gas sample given is venous rather than arterial. His blood gas also demonstrates an increased anion gap, consistent with his high lactate (generated by anaerobic respiration due to the inability to use available oxygen).The recommended treatment for moderate cyanide toxicity in the UK is one of three options: sodium thiosulfate, hydroxocobalamin or dicobalt edetate.
Among the options given is hydroxocobalamin and this is, therefore, the correct answer. Hydroxocobalamin additionally has the best side-effect profile and speed of onset compared with other treatments for cyanide poisoning.
Other options:
– Intubation would be appropriate treatment in the context of airway burns but this patient has no evidence of these, although close monitoring would be advised.
– High-flow oxygen is the treatment for carbon monoxide poisoning – a sensible differential, but this man’s very high lactate and high venous pO2 fit better with cyanide toxicity. Intravenous dexamethasone would be another treatment for airway oedema once an endotracheal tube had been placed.
– Intravenous sodium nitroprusside is a treatment for high blood pressure that can cause cyanide poisoning, and would, therefore, be inappropriate.Note:
Cyanide may be used in insecticides, photograph development and the production of certain metals. Toxicity results from reversible inhibition of cellular oxidizing enzymes
Clinical presentation:
Classical features: brick-red skin, the smell of bitter almonds
Acute: hypoxia, hypotension, headache, confusion
Chronic: ataxia, peripheral neuropathy, dermatitisManagement:
Supportive measures: 100% oxygen
Definitive: hydroxocobalamin (intravenously), also a combination of amyl nitrite (inhaled), sodium nitrite (intravenously), and sodium thiosulfate (intravenously). -
This question is part of the following fields:
- Pharmacology
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Question 2
Correct
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A 25-year-old pregnant female suddenly developed a rash on her torso. It started as macules and then became vesicles. After 3 days she died. During her post-mortem, positive findings suggestive of pneumonitis were found. Which one of the following is the most common cause?
Your Answer: Varicella zoster virus (VZV)
Explanation:Varicella zoster virus (VZV) presents in this way and the rash transforms from macules to vesicles. Pneumonitis is a common complication of VZV infection.
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This question is part of the following fields:
- Infectious Diseases
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Question 3
Incorrect
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A 25-year-old woman is reviewed in clinic. She was previously treated with omeprazole, amoxicillin and clarithromycin for Helicobacter pylori (H. pylori). She remains on PPI therapy but continues to have epigastric discomfort. You suspect she has ongoing H. pylori infection and request a urea breath test to investigate this. How long would the patient need to stop her PPI therapy before the urea breath test?
Your Answer:
Correct Answer: 14 days
Explanation:PPI will affect the accuracy of the test. In general, most recommend discontinuing PPI therapy for 2 weeks prior to a urea breath test. PPI’s have an anti-H. pylori effect.
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This question is part of the following fields:
- Gastroenterology
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Question 4
Incorrect
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Café-au-lait spots are seen in each of the following, except:
Your Answer:
Correct Answer: Friedreich's ataxia
Explanation:Café-au-lait spots is hyperpigmented lesions that vary in colour from light brown to dark brown, with borders that may be smooth or irregular. Causes include:
Neurofibromatosis type I
McCune–Albright syndrome
Legius syndrome
Tuberous sclerosis
Fanconi anaemia
Idiopathic
Ataxia-telangiectasia
Basal cell nevus syndrome
Benign congenital skin lesion
Bloom syndrome
Chediak-Higashi syndrome
Congenital nevus
Gaucher disease
Hunter syndrome
Maffucci syndrome
Multiple mucosal neuroma syndrome
Noonan syndrome
Pulmonary Stenosis
Silver–Russell syndrome
Watson syndrome
Wiskott–Aldrich syndrome -
This question is part of the following fields:
- Dermatology
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Question 5
Incorrect
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A 15-year-old girl is referred to the paediatric unit with reduced urine output and lethargy. She has been passing bloody diarrhoea for the past four days. On admission she appears dehydrated. Bloods show the following: Na+ 142 mmol/L, K+ 4.8 mmol/L, Bicarbonate 22 mmol/L, Urea 10.1 mmol/L, Creatinine 176 µmol/L, Hb 10.4 g/dL, MCV 90 fl Plt 91 * 109/L, WBC 14.4 * 109/L, Given the likely diagnosis, which one of the following organisms is the most likely cause?
Your Answer:
Correct Answer: E. coli
Explanation:The likely diagnosis in this case is Haemolytic Uremic Syndrome (HUS), which is generally seen in young children presenting with a triad of symptoms, namely: acute renal failure, microangiopathic haemolytic anaemia, and thrombocytopenia. The typical cause of HUS is ingestion of a strain of Escherichia coli.
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This question is part of the following fields:
- Nephrology
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Question 6
Incorrect
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A study is done on 1000 patients to assess the specificity of a new rapid finger-prick blood test developed to help diagnose deep vein thrombosis (DVT). The new test was positive on 200 patients with DVT and on 100 patients without DVT. It was also negative on 20 patients with DVT and 680 without DVT. What is the specificity of the new test?
Your Answer:
Correct Answer: 680/780
Explanation:Specificity (negative in health)
The ability of a test to correctly classify an individual as disease- free is called the test′s specificity. [Table 2]Specificity = d / b+d
= d (true negative) / b+d (true negative + false positive)
= Probability of being test negative when disease absent.
Example: One hundred persons with normal angles (diagnosed by ′gold standard′: gonioscopy) are examined by peripheral angle chamber depth examination. Eighty-five persons had normal peripheral angle chamber depth [Table 3]. The specificity of the peripheral angle chamber depth examination to PACG is therefore –
85 / 100 = 85%.
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This question is part of the following fields:
- Clinical Sciences
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Question 7
Incorrect
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A 78 year old woman presents to the clinic complaining of left sided temporal headaches and jaw claudication that has been going on for a month. A left temporal artery biopsy is negative. Results show: Hb: 130g/l Platelets: 359*109/L, WBC: 10*109/L, CRP: 89mg/l Which of the following options would be the next best step in the management of this patient?
Your Answer:
Correct Answer: Commence prednisolone
Explanation:Temporal arteritis is a chronic large- and medium-sized vessel vasculitis that typically involves the temporal arteries. Classical symptoms include temporal headaches, jaw claudication, amaurosis fugax. Physical exam shows scalp tenderness, palpation of the temporal area may demonstrate an absent pulse, knot-like swelling and vision loss. Lab results reveal an increased erythematous sedimentation rate and C-reactive protein. Temporal artery biopsy confirms the diagnosis. Management approach: high-dose systemic corticosteroids should be promptly administered even before the diagnosis is established. Temporal artery biopsy confirms the diagnosis. Inability to manage this or administer glucocorticoids might lead to development of blindness.
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This question is part of the following fields:
- Rheumatology
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Question 8
Incorrect
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A 50-year-old woman is referred to the outpatient clinic with a 6-month history of diarrhoea. She has had intermittent loose normal-coloured stools 2-3 times a day. She also has up to 10 hot flushes a day but thinks she is entering menopause; her GP has recently started her on hormone replacement therapy. 15 years ago she had a normal colonoscopy after presenting with abdominal pain and intermittent constipation. She has asthma controlled by inhalers, hypertension controlled by ACE inhibitors and hypothyroidism controlled by thyroxine. She smoked 10 cigarettes a day for the last 30 years and drinks alcohol about 14 units/week. On examination, she looks hot and flushed. She is afebrile. Her pulse is regular 92bpm and her BP is 164/82 mmHg. Her respirator rate is 20 breaths/min at rest and she sounds quite wheezy. A widespread polyphonic expiratory wheeze can be heard on chest auscultation. Her abdomen is soft. Her liver is enlarged 4 cm below the right costal margin but not-tender. Results of blood tests show: Na 140 mmol/L, K 4.8 mmol/L, Glucose 9.8 mmol/L, Albumin 41 g/l, ALT 94 U/l, ALP 61 U/l, Bilirubin 18 mmol/L, Ca 2.47 mmol/L, WCC 10.1 × 109/L, Hb 12.2 g/dL, MCV 90.5 fl, Platelets 234 × 109 /l, PT 13 s. Chest X-ray is normal. Ultrasound of the liver shows an enlarged liver containing three ill-defined mass lesions in the right lobe. What is the most likely diagnosis?
Your Answer:
Correct Answer: Carcinoid syndrome
Explanation:Carcinoid tumours are of neuroendocrine origin and derived from primitive stem cells in the gut wall, especially the appendix. They can be seen in other organs, including the lungs, mediastinum, thymus, liver, bile ducts, pancreas, bronchus, ovaries, prostate, and kidneys. While carcinoid tumours tend to grow slowly, they have the potential to metastasise.
Signs and symptoms seen in larger tumours may include the following:
– Periodic abdominal pain: Most common presentation for a small intestinal carcinoid; often associated with malignant carcinoid syndrome.
– Cutaneous flushing: Early and frequent (94%) symptom; typically affects head and neck.
– Diarrhoea and malabsorption (84%): Watery, frothy, or bulky stools, gastrointestinal (GI) bleed or steatorrhea; may or may not be associated with abdominal pain, flushing, and cramps.
– Cardiac manifestations (60%): Valvular heart lesions, fibrosis of the endocardium; may lead to heart failure with tachycardia and hypertension.
– Wheezing or asthma-like syndrome (25%): Due to bronchial constriction; some tremors are relatively indolent and result in chronic symptoms such as cough and dyspnoea.
– Pellagra with scale-like skin lesions, diarrhoea and mental disturbances.
– Carcinoid crisis can be the most serious symptom of the carcinoid tumours and life-threatening. It can occur suddenly or after stress, including chemotherapy and anaesthesia. -
This question is part of the following fields:
- Endocrinology
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Question 9
Incorrect
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All of the following statements regarding glucagon-like peptide-1 (GLP-1) are true, except?
Your Answer:
Correct Answer: Increased levels are seen in type 2 diabetes mellitus
Explanation:Glucagon-like peptide 1 (GLP-1) is a 30-amino acid peptide hormone produced in the intestinal epithelial endocrine L-cells by differential processing of proglucagon. GLP-1 is released in response to meal intake.
The main actions of GLP-1 are to stimulate insulin secretion (i.e., to act as an incretin hormone) and to inhibit glucagon secretion, thereby contributing to limit postprandial glucose excursions. It also inhibits gastrointestinal motility and secretion and thus acts as an enterogastrone and part of the ileal brake mechanism. GLP-1 also appears to be a physiological regulator of appetite and food intake.
Decreased secretion of GLP-1 may contribute to the development of obesity, and exaggerated secretion may be responsible for postprandial reactive hypoglycaemia. -
This question is part of the following fields:
- Endocrinology
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Question 10
Incorrect
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A patient who has recently been diagnosed with SLE undergoes serum testing. A rise in which of the following antibodies would indicate severe systemic involvement?
Your Answer:
Correct Answer: Anti double-stranded DNA antibodies
Explanation:Anti ds-DNA antibodies are very specific for SLE and their presence most often indicates systemic spread of the disease. These antibodies are present in about 30 percent of the total cases of SLE.
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This question is part of the following fields:
- Rheumatology
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Question 11
Incorrect
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From the options provided below, which intervention plays the greatest role in increasing survival in patients with COPD?
Your Answer:
Correct Answer: Smoking cessation
Explanation:Smoking cessation is the most effective intervention in stopping the progression of COPD, as well as increasing survival and reducing morbidity. This is why smoking cessation should be the top priority in the treatment of COPD. Long term oxygen therapy (LTOT) may increase survival in hypoxic patients. The rest of the options dilate airways, reduce inflammation and thereby improve symptoms but do not necessarily increase survival.
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This question is part of the following fields:
- Respiratory
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Question 12
Incorrect
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A 25-year-old female patient presents with massive haemorrhage. After grouping, her blood sample comes out to be B RhD negative. You work in the hospital's blood bank and are asked to prepare two units each of red blood cells (RBCs) and fresh frozen plasma (FFP). You manage to obtain the RBCs but not the Group B FFP as it is unavailable. Therefore, out of the following, FFP from a donor of which blood group would be best to transfuse?
Your Answer:
Correct Answer: AB RhD negative
Explanation:Group AB donors are the universal donors of FFP. This is because they produce neither anti-A nor anti-B antigens in their plasma and are, therefore, compatible with all ABO groups.
The aforementioned patient’s blood group is B meaning, thereby, she naturally produces anti-A antigens in her plasma and would need to receive plasma that does not have anti-B antigens in it. Hence, she can only receive FFP from donors of group B or AB. Moreover, as she is of childbearing age, she must receive RhD negative blood in order to avoid problems with future pregnancies if her foetus would be RhD positive.
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This question is part of the following fields:
- Haematology & Oncology
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Question 13
Incorrect
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A 52-year-old man presents with numbness and tingling in his left hand. On examination he has weakness of elbow extension, metacarpophalangeal joint flexion and extension and distal interphalangeal joint flexion. All other movements and reflexes are normal. Sensation is normal apart from reduced pin-prick sensation over the medial aspect of the hand. An MRI scan of the cervical spine is performed due to suspicion of a nerve lesion. Which of the following pathologies is most likely to be found on the scan based on the clinical findings?
Your Answer:
Correct Answer: Disc herniation between C7 and T1
Explanation:The C8 nerve forms part of the radial and ulnar nerves via the brachial plexus, and therefore has motor and sensory function in the upper limb. It originates from the spinal column from below the cervical vertebra 7 (C7).
The C8 nerve receives sensory afferents from the C8 dermatome. This consists of all the skin on the little finger, and continuing up slightly past the wrist on the palmar and dorsal aspects of the hand and forearm.
The other options available correspond to the C6 or C7 roots and these are unaffected as evidenced by normal elbow flexion and thumb sensation (C6) and normal sensation over the middle finger (C7). Elbow extension is weak as it has roots from both C7 and C8 and so cannot be used alone to decide between the two levels clinically.
The C8 nerve contributes to the motor innervation of many of the muscles in the trunk and upper limb. Its primary function is the flexion of the fingers, and this is used as the clinical test for C8 integrity, in conjunction with the finger jerk reflex.Trunk:
– Pectoralis major – Medial and lateral pectoral nerves (C5, C6, C7, C8, T1)
– Pectoralis minor – Medial pectoral nerve (C5, C6, C7,C8, T1)
– Latissimus dorsi – Thoracodorsal nerve (C6, C7, C8)
Upper arm:
– Triceps brachii – Radial nerve (C6, C7,C8)
Forearm
– Flexor carpi ulnaris – Ulnar nerve (C7, C8, T1)
– Palmaris longus – Median nerve (C7,C8)
– Flexor digitorum superficialis – Median nerve (C8, T1)
– Flexor digitorum profundus – Median and Ulnar nerves (C8, T1)
– Flexor pollicis longus – Median nerve (C7,C8)
– Pronator quadratus – Median nerve (C7,C8)
– Extensor carpi radialis brevis – Deep branch of the radial nerve (C7,C8)
– Extensor digitorum – Posterior interosseous nerve (C7,C8)
– Extensor digiti minimi – Posterior interosseous nerve (C7,C8)
– Extensor carpi ulnaris – Posterior interosseous nerve (C7,C8)
– Anconeus – Radial nerve (C6, C7,C8)
– Abductor pollicis longus – Posterior interosseous nerve (C7,C8)
– Extensor pollicis brevis – Posterior interosseous nerve (C7,C8)
– Extensor pollicis longus – Posterior interosseous nerve (C7,C8)
– Extensor indicis – Posterior interosseous nerve (C7,C8)
Hand
– Palmaris brevis – Superficial branch of ulnar nerve (C8, T1)
– Dorsal interossei – Deep branch of ulnar nerve (C8, T1)
– Palmar interossei – Deep branch of ulnar nerve (C8, T1)
– Adductor pollicis – Deep branch of ulnar nerve (C8, T1)
– Lumbricals – Deep branch of ulnar, Digital branches of median nerve
– Opponens pollicis – Recurrent branch of median nerve (C8, T1)
– Abductor pollicis brevis – Recurrent branch of median nerve (C8, T1)
– Flexor pollicis brevis – Recurrent branch of median nerve (C8, T1)
– Opponens digiti minimi – Deep branch of ulnar nerve (C8, T1)
– Abductor digiti minimi – Deep branch of ulnar nerve (C8, T1)
– Flexor digiti minimi brevis – Deep branch of ulnar nerve (C8, T1) -
This question is part of the following fields:
- Clinical Sciences
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Question 14
Incorrect
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A 77 year old mail carrier presents to the emergency department with severe flinging movements of his left arm. Where would the causative lesion be located?
Your Answer:
Correct Answer: Right subthalamic nucleus
Explanation:Hemiballismus is a hyperkinetic involuntary movement disorder characterized by intermittent, sudden, violent, involuntary, flinging, or ballistic high amplitude movements involving the ipsilateral arm and leg caused by dysfunction in the central nervous system of the contralateral side.Global incidence and prevalence are largely unknown, given the wide variety of etiologies but estimated to be 1-2/1,000,000, classifying it as a rare disorder. -
This question is part of the following fields:
- Neurology
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Question 15
Incorrect
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A 23-year-old male patient with a downward dislocation of the lens in his right eye is experiencing visual problems. The ophthalmologist notes a constellation of symptoms resembling those of Marfan Syndrome. The patient's history reveals learning disabilities and a diagnosis of homocystinuria is suspected. What is the pathophysiology of homocystinuria?
Your Answer:
Correct Answer: Deficiency of cystathionine beta synthase
Explanation:Inherited metabolic disorders are often characterized by the lack of an essential enzyme and are currently treated by dietary restriction and other strategies to replace the substrates or products of the missing enzyme. Patients with homocystinuria lack the enzyme cystathionine β-synthase (CBS), and many of these individuals do not respond to current treatment protocols.
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This question is part of the following fields:
- Clinical Sciences
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Question 16
Incorrect
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Briefly state the mechanism of action of salbutamol.
Your Answer:
Correct Answer: Beta2 receptor agonist which increases cAMP levels and leads to muscle relaxation and bronchodilation
Explanation:Salbutamol stimulates beta-2 adrenergic receptors, which are the predominant receptors in bronchial smooth muscle (beta-2 receptors are also present in the heart in a concentration between 10% and 50%).
Stimulation of beta-2 receptors leads to the activation of enzyme adenyl cyclase that forms cyclic AMP (adenosine-mono-phosphate) from ATP (adenosine-tri-phosphate). This increase of cyclic AMP relaxes bronchial smooth muscle and decrease airway resistance by lowering intracellular ionic calcium concentrations. Salbutamol relaxes the smooth muscles of airways, from trachea to terminal bronchioles.
Increased cyclic AMP concentrations also inhibits the release of bronchoconstrictor mediators such as histamine and leukotriene from the mast cells in the airway.
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This question is part of the following fields:
- Respiratory
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Question 17
Incorrect
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A 42 yr. old male patient who was on enalapril for hypertension presented with generalized body weakness. Investigations revealed hyperkalaemia. Which of the following can be expected in his ECG?
Your Answer:
Correct Answer: Tall, tented T waves
Explanation:In hyperkalaemia the ECG will show tall, tented T waves as well as small P waves and widened QRS complexes.
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This question is part of the following fields:
- Cardiology
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Question 18
Incorrect
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A study is carried out to assess the efficacy of a new anti-epileptic drug for children with absence seizures. The total number of the children selected for the study was 400, from which 150 children were assigned to take the new drug and 250 children were assigned in the control group. After a period of four months, only 15 children taking the new drug had a seizure compared to 100 children from the control group who had seizure. What is the correct value regarding the relative risk reduction?
Your Answer:
Correct Answer: 75%
Explanation:Relative risk reduction (RRR) tells you by how much the treatment reduced the risk of bad outcomes relative to the control group who did not have the treatment. In the previous example, the relative risk reduction of fever and rash in the group of the children on the intervention was 40 per cent (1 – 0.6 = 0.4 or 40 per cent). RRR = (EER -CER) / CER = (0.1 – 0.4) / 0.4 = -0.75 or 75% reduction.
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This question is part of the following fields:
- Clinical Sciences
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Question 19
Incorrect
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A 53-year-old cashier with a history of chronic back pain presents for a check-up. He is aware of a dragging feeling affecting his left foot when he tries to walk. This has developed since a minor injury to his left knee. On examination, he has weakness of dorsiflexion and eversion of the left foot. The right is unaffected and plantar flexion and inversion are normal on the left. MRI of the spinal cord shows degenerative disc changes at multiple levels, but no evidence of cord or nerve root impingement. Nerve conduction studies and EMG results are pending. Which of the following sensory loss patterns would you expect to find in association with this motor defect?
Your Answer:
Correct Answer: Sensory loss over the dorsum of the foot and anterolateral leg
Explanation:This patient presentation is unlikely to be an L5 nerve root lesion given the results of the MRI scan. Therefore, the most likely diagnosis is a mononeuritis affecting the left common peroneal nerve. This would lead to sensory loss over the dorsum of the foot and anterolateral leg on the left.
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This question is part of the following fields:
- Neurology
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Question 20
Incorrect
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A 61-year-old gentleman presents with heart failure and pedal oedema. The oedema occurs due to:
Your Answer:
Correct Answer: Increased release of renin
Explanation:The oedema is an effect of the a decreased cardiac output that increases renin release which leads to vasoconstriction and sodium and water retention.
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This question is part of the following fields:
- Nephrology
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