Secretin is a peptide hormone produced in the S cells of the duodenum, which are located in the intestinal glands. In humans, the secretin peptide is encoded by the SCT gene.
Secretin helps regulate the pH of the duodenum by
1) inhibiting the secretion of gastric acid from the parietal cells of the stomach and
(2) stimulating the production of bicarbonate from the ductal cells of the pancreas.
G cells in the antrum of the stomach release gastrin
I cells in upper small intestine release CCK
D cells in the pancreas & stomach secrete somatostatin
K cells secrete gastric inhibitory peptide, an incretin, which also promotes triglyceride storage.

In general, the aim is to keep the homocysteine (Hcy) concentration as close to normal as possible. In patients who are fully-responsive to pyridoxine, standard doses can lead to tHcy levels below 50 μmol/L (and sometimes within the normal range). Some patients who are partially-responsive to pyridoxine may be able to achieve a tHcy level below 50 μmol/L if they are also on a low-Met diet; for others it is not a realistic goal.

Hemiballismus or hemiballism in its unilateral form is a very rare movement disorder. It is a type of chorea caused in most cases by a decrease in activity of the subthalamic nucleus of the basal ganglia, resulting in the appearance of flailing, ballistic, undesired movements of the limbs. Symptoms may decrease while the patient is asleep. Antidopaminergic agents (e.g. Haloperidol) are the mainstay of treatment.

Protein-calorie malnutrition is observed in almost 50% of dialysis patients, contributing to increased morbidity and mortality. All the other complications listed can usually be prevented thanks to modern-day dialysis techniques.

A case-control study is designed to help determine if an exposure is associated with an outcome (i.e., disease or condition of interest). In theory, the case-control study can be described simply. Case-control studies have specific advantages compared to other study designs. They are comparatively quick, inexpensive, and easy. They are particularly appropriate for (1) investigating outbreaks, and (2) studying rare diseases or outcomes. Sudden infant death syndrome is a rare medical event, thus case-control study is the most suitable option.

West Nile virus (WNV) is a single-stranded RNA flavivirus transmitted via the culex mosquito. This previously ‘tropical’ disease has became topical in recent years following a large scale outbreak in the New York area. Incidence of neurological involvement is around 1%, although some suggest that the incidence of meningoencephalitis in America is higher than in other parts of the world. Risk factors for neurological involvement include increasing age, and immunosuppression. The usual picture is of sudden onset fever and myalgia with nausea and vomiting and a non-specific rash. Transient meningitis is occasionally seen. Frank meningoencephalitis is seen in two-thirds of cases with neurological involvement; 15% progress to coma. A flaccid paralysis similar to acute Guillain–Barré is increasingly recognised.
Diagnosis is initially clinical with subsequent serological confirmation. Treatment is supportive; results from trials of antivirals have yielded disappointing results.

Melanocytic naevi are skin tumours produced by melanocytes. They usually present in childhood but increase during puberty. The mnemonic A-B-C-D, is used by institutions to assess for suspicion of malignancy. The letters stand for asymmetry, border, colour, and diameter. If a mole starts changing in size, colour, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include if it begins to crust over, bleed, itch, or become inflamed.

The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.

Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.
Methadone should be used with caution if the patient has:
Respiratory deficiency
Acute alcohol dependence
Head injury
Treatment with monoamine oxidase inhibitors (MAOIs)
Ulcerating colitis or Crohn’s disease
Severe hepatic impairment
The dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms.

To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.

It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given.
It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.

This case describes Zollinger-Ellison syndrome. It is characterized by refractory peptic ulcer disease, often multiple ulcers. This is typically caused by secretion of gastrin from a gastrinoma, a neuroendocrine tumour. The most common site of ulceration is the duodenum. A symptom of a pancreatic gastrinoma may be steatorrhea from the hypersecretion of gastrin. Serum gastrin levels > 1000 and a pH < 2 are diagnostic of pancreatic gastrinoma. None of the other answer choices are a better answer than this. CT abdomen may potentially show a tumour, but this is not diagnostic for type.

Most patients with psoriatic arthritis present with monoarthritis or asymmetric oligoarthritis. The most common form of the disease is the one involving a few joints of the peripheral skeleton with a distinct asymmetry of symptoms. Involvement of the smaller joints of the hands and feet, especially distal interphalangeal joints, seems to be a characteristic feature. Arthritis mutilans is a rare and severe complication of psoriatic arthritis.

Serial Peak Expiratory Flow measurement at work and home is a feasible, sensitive, and specific test for the diagnosis of occupational asthma. For a diagnosis of occupational asthma, it is important to establish a relationship objectively between the workplace exposure and asthma symptoms and signs. Physiologically, this can be achieved by monitoring airflow limitation in relation to occupational exposure(s). If there is an effect of a specific workplace exposure, airflow limitation should be more prominent on work days compared with days away from work (or days away from the causative agent). Airflow limitation can be measured by spirometry, with peak expiratory flow (PEF) and/or forced expiratory volume in 1 s(FEV1) being the most useful for observing changes in airway calibre. Other tests mentioned are less reliable and would not help in establishing a satisfactory diagnosis of occupational asthma.

Lesions in the optic radiation can cause a homonymous hemianopia with macular sparing, as a result of collateral circulation offered to macular tracts by the middle cerebral artery.
Lesions in the optic tract also cause a homonymous hemianopia, but without macular sparing.
Lesions in the optic chiasm, optic nerve, and temporal lobe cause bitemporal hemianopia, ipsilateral complete blindness, and superior homonymous quadrantanopia respectively.

1B: Individual Randomised Control Trial (with narrow confidence intervals)

After the exposure to chickenpox while pregnant, even if the patient is negative for antibodies she requires immunoglobulin to prevent further issues.

This is a typical picture of acute chest syndrome (ACS). According to the British Committee for Standards in Haematology (BCSH), ACS is defined as ‘an acute illness characterised by fever and/or respiratory symptoms, accompanied by a new pulmonary infiltrate on chest X-ray’. ACS occurs in sequestration crisis, which is one of the four main types of crises occurring in sickle cell disease.

The fundamentals of initial management are as follows:
1. Oxygen therapy to maintain saturation >95%
2. Intravenous fluids to ensure euvolemia
3. Adequate pain relief
4. Incentive spirometry in all patients presenting with rib or chest pain
5. Antibiotics with cover for atypical organisms
6. Bronchodilators if asthma co-exists with acute chest syndrome, or if there is an evidence of acute bronchospasm on auscultation
7. Early consultation with the critical care team and haematology department

A senior haematologist then makes a decision as to whether a simple or exchange transfusion is necessary in order to achieve a target Hb of 10.0–11.0g/dL in either instance.

Sickle Cell Crises:
Sickle cell anaemia is characterised by periods of good health with intervening crises:
1. Sequestration crisis: acute chest syndrome (i.e. fever, dyspnoea, chest/rib pain, low pO2, and pulmonary infiltrates)

2. Thrombotic (painful or vaso-occlusive) crisis: precipitated by infection, dehydration, and deoxygenation

3. Aplastic crisis: sudden fall in haemoglobin without marked reticulocytosis, usually occurring secondary to parvovirus infection

4. Haemolytic crisis: fall in haemoglobin secondary to haemolysis, rare type of sickle cell crises

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are immediately treated with inhaled beta2 agonists and inhaled anticholinergics, followed by antibiotics (if indicated) and systemic corticosteroids. Methylxanthine therapy may be considered in patients who do not respond to other bronchodilators.
High flow oxygen would worsen his symptoms. Usually titrated oxygen (88 to 92 %) is given in such patients to avoid the risk of hyperoxic hypercarbia in which increasing oxygen saturation in a chronic carbon dioxide retainer can inadvertently lead to respiratory acidosis and death.

Becks triad (hypotension, elevated systemic venous pressure, often with jugular venous distention and muffled heart sounds) is a characteristic collection of clinical findings found in cardiac tamponade. Pulsus paradoxus is also associated with it. The history and clinical findings in this scenario are compatible with the diagnosis of cardica tamponade. The normal respiratory examination excludes tension pneumothorax.

A single dose of intravenous magnesium sulphate is safe and may improve lung function and reduce intubation rates in patients with acute severe asthma. Intravenous magnesium sulphate may also reduce hospital admissions in adults with acute asthma who have had little or no response to standard treatment.

Consider giving a single dose of intravenous magnesium sulphate to patients with acute severe asthma (PEF <50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy. Magnesium sulphate (1.2–2 g IV infusion over 20 minutes) should only be used following consultation with senior medical staff.

Lidocaine is an example of class IB antiarrhythmics.

The Vaughan-Williams classification of antiarrhythmics
I: Membrane stabilizing agents
IA: Quinidine, Procainamide, Disopyramide
IB: Lidocaine, Mexiletine
IC: Propafenone, Flecainide
II: β blockers – Propranolol, Esmolol
III: Agents widening AP – Amiodarone, Dronedarone, Dofetilide, Ibutilide, Sotalol
IV: Calcium channel blockers – Verapamil, Diltiazem
V: Miscellaneous – Digoxin, adenosine, magnesium

The patient’s underlying arthritis has most likely led to Renal tubular acidosis RTA type 1, which presents with the following symptoms consistent with the presentation of the patient: Normal anion gap metabolic acidosis/acidaemia, hypokalaemia and hyperchloremia. Comparatively, the other conditions are ruled out because Aspirin and diabetic ketoacidosis is associated with a raised anion gap, Conn’s syndrome explains hypokalaemia but not the metabolic acidosis, and RTA type 4 is associated with hyperkalaemia.