An odds ratio (OR) is a measure of the association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. Odds ratios are most commonly used in case-control studies, however they can also be used in cross-sectional and cohort study designs as well (with some modifications and/or assumptions). Where

a = Number of exposed cases

b = Number of exposed non-cases

c = Number of unexposed cases

d = Number of unexposed non-cases

OR=(a/c) / (b/d) = ad/bc

Acute dacryocystitis presents as inflammation of the lacrimal sac and is typically caused by infection. Symptoms of acute dacryocystitis can be pain, redness of the eye and swelling of the nasal aspect of the eye. The eye is usually watery and discharge can be expressed through the lacrimal punctum which is generally mucoid but can also be purulent. Patient can also present with fever.

CHA₂DS₂-VASc score is used for atrial fibrillation stroke risk calculation.
Congestive heart failure – 1 point
Hypertension – 1 point
Age ≥75 years – 2 points
Diabetes mellitus – 1 point
Stroke/Transient Ischemic Attack/Thromboembolic event – 2 points
Vascular disease (prior MI, PAD, or aortic plaque) – 1 point
Age 65 to 74 years – 1 point
Sex category (i.e., female sex) – 1 point
Score of 2 or more is considered as high risk and anticoagulation is indicated. This patient’s score is 4, so he needs life-long warfarin to prevent a stroke.

Giardiasis also known as travellers diarrhoea is caused by Giardia lamblia, which is an anaerobic parasite affecting the small intestine. It can lead to diarrhoea, flatulence, abdominal cramps, malodourous greasy stools and intestinal malabsorption. It can also cause bloody diarrhoea. The investigation of choice is stool examination for trophozoites and cysts. It is treated by metronidazole and tinidazole as first line therapies.

J waves in an ECG is associated with hypothermia, hypercalcemia, the Brugada syndrome, and idiopathic ventricular fibrillation. The other responses are all associated with atrial myxoma

Tumour marker CA 15-3 is mostly associated with breast cancer.

Tumour markers can be divided into:
1. Monoclonal antibodies
CA 125: Ovarian cancer, primary peritoneal cancer
CA 19-9: Pancreatic cancer
CA 15-3: Breast cancer

2. Tumour specific antigens
Prostate specific antigen (PSA): Prostatic carcinoma
Alpha-feto protein (AFP): Hepatocellular carcinoma, teratoma
Carcinoembryonic antigen (CEA): Colorectal cancer
S-100: Melanoma, schwannomas
Bombesin: Small cell lung carcinoma, gastric cancer

3. Enzymes
Alkaline phosphatase (ALP)
Neuron specific enolase (NSE)

4. Hormones
Calcitonin
Antidiuretic hormone (ADH)
Human chorionic gonadotropin (hCG)

The most likely cause for acute breathlessness is due to papillary muscle rupture which causes mitral regurgitation.

The CD15 antigen, also known as Lewis (hapten)X, serves as an immuno-phenotypic marker for Reed-Sternberg cells and its expression has diagnostic, but also prognostic significance in Hodgkin Lymphoma.

Hydroxychloroquine is used in the management of SLE as it prevents disease progression and has relatively mild side effects, for instance headache, nausea etc. Its use reduces the usage of corticosteroids. It is particularly effective when the disease is less severe and there is no organ involvement. Cyclophosphamide and prednisolone are indicated in cases of renal, neurological and lung involvement.

Absolute risk reduction (ARR) – also called risk difference (RD) – is the most useful way of presenting research results to help your decision-making. In this example, the ARR is 8 per cent (20 per cent – 12 per cent = 8 per cent). This means that, if 100 children were treated, 8 would be prevented from developing bad outcomes. Another way of expressing this is the number needed to treat (NNT). If 8 children out of 100 benefit from treatment, the NNT for one child to benefit is about 13 (100 ÷ 8 = 12.5). CER = 20 / 400 = 1 / 20 = 0.05, EER = 10 / 400 = 0.025, ARR =CER – EER = 0.025

Fundoscopy reveals flame-shaped haemorrhages which are specific to central retinal vein occlusion (CRVO). In CRA thrombosis, fundoscopy would show a cherry-red spot. A patient with retinal detachment would give a characteristic history of seeing flashes of light and floaters. Background retinopathy is associated with diabetes.

According to NICE guidelines (2013) all people who have had an acute MI, treatment should be offered with ACE inhibitor, dual antiplatelet therapy (aspirin plus a second antiplatelet agent), beta-blocker and a statin.

Rotterdam criteria for the diagnosis of polycystic ovary syndrome:
Two of the following three criteria are required:
1. Oligo/anovulation
2. Hyperandrogenism
– Clinical (hirsutism or less commonly male pattern alopecia) or
– Biochemical (raised FAI or free testosterone)
3. Polycystic ovaries on ultrasound
Other aetiologies must be excluded such as congenital adrenal hyperplasia, androgen-secreting tumours, Cushing syndrome, thyroid dysfunction and hyperprolactinaemia.
Cushing’s is excluded because there would have been marked obesity, hypertension and other related features.

Tetracycline is not recommended in pregnancy because of the risk to fetal development (bones, teeth!). Metronidazole in pregnancy: currently not thought to be an increased risk in pregnancy; however this is not effective against chlamydia. Amoxicillin is shown to be an adequate treatment for chlamydia, so this is the correct answer.

Hepatorenal syndrome is renal vasoconstriction that cannot overcome the effects of splanchnic vasodilation. Vasoactive mediators cause this splanchnic vasodilation, reducing SVR, which is sensed by the juxtaglomerular apparatus, activating the RAAS system, leading to renal vasoconstriction. However, the overall splanchnic vasodilation effect is greater than this renal vasoconstriction effect.

The rationale behind the use of sodium bicarbonate is that it increases the alkalinity of the urine promoting lithium excretion. The preferred treatment in severe cases would be haemodialysis.

Lithium is a mood-stabilizing drug used most commonly prophylactically in bipolar disorder but also as an adjunct in refractory depression. It has a very narrow therapeutic range (0.4-1.0 mmol/L) and a long plasma half-life being excreted primarily by the kidneys. Lithium toxicity generally occurs following concentrations > 1.5 mmol/L.

Toxicity may be precipitated by dehydration, renal failure, diuretics (especially Bendroflumethiazide), ACE inhibitors, NSAIDs and metronidazole.

Features of toxicity
Coarse tremor (a fine tremor is seen in therapeutic levels)
Hyperreflexia
Acute confusion
Seizure
Coma

Management
Mild-moderate toxicity may respond to volume resuscitation with normal saline
Haemodialysis may be needed in severe toxicity
Sodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of the urine it promotes lithium excretion.

The most suitable management step for tetanus prevention in this scenario would be to ensure that the individual receives a tetanus toxoid-containing vaccine if they have not had a booster dose within the last five years. Tetanus toxoid-containing vaccines are routinely given during childhood immunization schedules, but booster doses are recommended every 10 years thereafter to maintain immunity. Since the individual’s immunization history is up to date, if they have received their primary series of tetanus vaccinations and a booster dose within the last five years, no further action would be needed regarding tetanus prevention.

However, if the individual’s immunization status is uncertain or if it has been more than five years since their last tetanus booster, they should receive a tetanus toxoid-containing vaccine promptly. Additionally, if the wound is contaminated or considered high risk for tetanus infection, tetanus immune globulin (TIG) may also be administered for immediate protection against tetanus toxins.

Because the patient has chronic kidney disease, we need to consider the associated adverse effects of trying to maintain normal haemoglobin levels (14-18g/dl in this patient) and instead only instigate therapy when the level falls below 11 g/dl. Thus, in this case we should just monitor the haemoglobin levels and not initiate therapy just yet.

Given that he has diverticula in the clinical scenario combined with his presenting symptoms, it is likely that he has diverticular disease. A low fibre diet would support this diagnosis. Acute diverticulitis would require treatment with antibiotics. Depending on the severity (Hinchey classification) would determine if he needs oral or IV antibiotics, hospital admission or outpatient treatment. Sometimes abscesses or micro perforations occur, which typical require drainage and possibly surgical intervention. Diverticular disease is clearly a better answer than other possible answer choices, simply based on the symptoms presented in the prompt (and mention of low fibre).

DIAGNOSIS:
A consensus definition for hemodynamically significant PDA is lacking. The diagnosis is often suspected clinically, when an infant demonstrates signs of excessive shunting from the arterial to pulmonary circulation. Continuous or a systolic murmur; note, a “silent” PDA may also occur when the ductus shunt is large enough that nonturbulent flow fails to generate a detectible murmur.
A low diastolic blood pressure (due to runoff into the ductus during diastole, more frequent in the most premature infants).
A wide pulse pressure (due to ductus runoff or steal)Hypotension (especially in the most premature infants)
Bounding pulses
Increased serum creatinine concentration or oliguria
Hepatomegaly