Digoxin acts by inhibiting the Na+/K+ ATPase pump.
Digoxin is a cardiac glycoside now mainly used for rate control in the management of atrial fibrillation. As it has positive inotropic properties it is sometimes used for improving symptoms (but not mortality) in patients with heart failure.

Mechanism of action:
It decreases the conduction through the atrioventricular node which slows the ventricular rate in atrial fibrillation and atrial flutter.
It increases the force of cardiac muscle contraction due to inhibition of the Na+/K+ ATPase pump. It also stimulates the vagus nerve.

Digoxin toxicity:
Plasma concentration alone does not determine whether a patient has developed digoxin toxicity. The likelihood of toxicity increases progressively from 1.5 to 3 mcg/l.
Clinical feature of digoxin toxicity include a general feeling of unwell, lethargy, nausea & vomiting, anorexia, confusion, xanthopsia, arrhythmias (e.g. AV block, bradycardia), and gynaecomastia

Precipitating factors:
Hypokalaemia
Increasing age
Renal failure
Myocardial ischemia
Hypomagnesaemia, hypercalcemia, hypernatremia, acidosis
Hypoalbuminemia
Hypothermia
Hypothyroidism
Drugs: amiodarone, quinidine, verapamil, diltiazem, spironolactone (competes for secretion in the distal convoluted tubule, therefore, reduce excretion), ciclosporin. Also, drugs that cause hypokalaemia e.g. thiazides and loop diuretics.

Management of digoxin toxicity:
Digibind
Correct arrhythmias
Monitor and maintain potassium levels within the normal limits.

Absolute contraindications for fibrinolytic use in STEMI

Prior intracranial haemorrhage (ICH)
Known structural cerebral vascular lesion
Known malignant intracranial neoplasm
Ischemic stroke within 3 months
Suspected aortic dissection
Active bleeding or bleeding diathesis (excluding menses)
Significant closed head trauma or facial trauma within 3 months
Intracranial or intraspinal surgery within 2 months
Severe uncontrolled hypertension (unresponsive to emergency therapy)
For streptokinase, prior treatment within the previous 6 months

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.

Normal distribution describes the spread of many biological and clinical measurements. Usually, 68.3% lies within 1 standard deviation (SD) of the mean, 95.4% lies within 2 SD of the mean and 99.7% lies within 3 SD of the mean.

Pneumothorax is defined as air in the pleural space and may be classified as spontaneous, traumatic or iatrogenic. Primary spontaneous pneumothorax occurs in patients without clinically apparent lung disease.
Primary pneumothorax has an incidence of 18-28 per 100,000 per year for men and 1.2-6 per 100,000 per year for women. Most patients present with ipsilateral pleuritic chest pain and acute shortness of breath. Shortness of breath is largely dependent on the size of the pneumothorax and whether there is underlying chronic lung disease.

Young patients may have chest pain only. Most episodes of pneumothorax occur at rest. Symptoms may resolve within 24 hours in patients with primary spontaneous pneumothorax. The diagnosis of a pneumothorax is confirmed by finding a visceral pleural line displaced from the chest wall, without distal lung markings, on a posterior-anterior chest radiograph.

Breathless patients should not be left without intervention regardless of the size of pneumothorax. If there is a rim of air >2cm on the chest X-ray, this should be aspirated.
Aspiration is successful in approximately 70 per cent of patients; the patient may be discharged subsequently. A further attempt at aspiration is recommended if the patient remains symptomatic and a volume of less than 2.5 litres has been aspirated on the first attempt.

If unsuccessful, an intercostal drain is inserted. This may be removed after 24 hours after full re-expansion or cessation of air leak without clamping and discharge may be considered.

The definition of negative predictive value is the probability that the individuals with truly negative screening test don’t have Chlamydia. The equation is the following: Negative predictive value = Truly negative/(truly negative + false negative) = 172 / (172 + 5) = 172 / 177

Interferon alfa alone, not interferon alfa and ribavirin, has been shown to achieve HBeAg seroconversion for patients with HBeAg-positive chronic hepatitis B.

Staph. aureus is the most likely cause. It is found in foods like dairy products, cold meats, or mayonnaise. It produces a heat-stable ENDOTOXIN (remember this) that causes nausea, vomiting, and diarrhoea 1-6 hours after ingestion of contaminated food. B. cereus is classically associated with fried rice being reheated. Salmonella is typical with raw eggs and undercooked poultry. Campylobacter which is most commonly associated with food poisoning, is seen with poultry 50% of the time. Yersinia enterocolitica is seen with raw or undercooked pork, and may be a case presenting with mesenteric adenitis.

Free T4 levels or the free T4 index is usually elevated, as is the free T3 level or free T3 index
– Assays for thyrotropin-receptor antibodies (particularly TSIs) almost always are positive.
– Detection of TSIs is diagnostic for Graves disease.
– Other markers of thyroid autoimmunity, such as antithyroglobulin antibodies or antithyroid peroxidase antibodies, are usually present.
– Other autoantibodies that may be present include thyrotropin receptor-blocking antibodies and anti–sodium-iodide symporter antibody.
The presence of these antibodies supports the diagnosis of autoimmune thyroid disease.
– The radioactive iodine uptake is increased and the uptake is diffusely distributed over the entire gland.

This case presents with characteristic symptoms of SLE and with her renal biopsy results of focal glomerulonephritis, this is clearly Class III SLE.

The patient has Cushing syndrome suggested by the elevated 24hr urine free cortisol. Hence, the mass is most probably a cortisol secreting adenoma.

Citalopram is an antidepressant medication that works in the brain. It is approved for the treatment of major depressive disorder (MDD). Stopping citalopram abruptly may result in one or more of the following withdrawal symptoms: irritability, nausea, feeling dizzy, vomiting, nightmares, headache, and/or paraesthesia (prickling, tingling sensation on the skin).

When discontinuing antidepressant treatment that has lasted for >3 weeks, gradually taper the dose (e.g., over 2 to 4 weeks) to minimize withdrawal symptoms and detect re-emerging symptoms. Reasons for a slower titration (e.g., over 4 weeks) include use of a drug with a half-life <24 hours (e.g., paroxetine, venlafaxine), prior history of antidepressant withdrawal symptoms, or high doses of antidepressants.

Extra-nodal presentation is more common in non-Hodgkin lymphoma (NHL) than in Hodgkin lymphoma (HL). Bone marrow infiltration is more common in low-grade than in high-grade NHLs.

Low-grade NHL is predominantly a disease of older people. Most present with advanced disease, bone marrow infiltration being almost invariable. Anaemia, leucocytosis, and/or thrombocytopaenia in a patient are suggestive of bone marrow involvement. For definitive diagnosis, lymph node biopsy is sufficient.

The other aforementioned statements are ruled out because:
1. Renal impairment in NHL usually occurs as a consequence of ureteric obstruction secondary to intra-abdominal or pelvic lymph node enlargement.

2. Burkitt lymphoma is a high-grade NHL, which was first described in children in West Africa who presented with a jaw tumour, extra-nodal abdominal involvement, and ovarian tumours. It develops most often in children or young adults and is uncommon in older people.

3. High-grade lymphomas are potentially curable. They have a better prognosis and are responsive to chemotherapy unlike low-grade lymphomas, which are incurable with conventional therapy.

Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers. There usually is no rash and the diagnosis is unrelated to the presence of rheumatoid factor. This is a clinical diagnosis.

The a wave indicates atrial contraction. The c wave indicates ventricular contraction and resulting bulging of the tricuspid valve into the right atrium during isovolumetric systole. The v wave indicates venous filling. The x descent indicates the atrium relaxation and the movement of tricuspid valve downward. The y descent indicates the filling of the ventricle after the opening of the tricuspid valve.

High Altitude Cerebral Oedema (HACE) is a severe and potentially fatal manifestation of high altitude illness and is often characterized by ataxia, fatigue, and altered mental status. HACE is often thought of as an extreme form/end-stage of Acute Mountain Sickness (AMS). Although HACE represents the least common form of altitude illness, it may progress rapidly to coma and death as a result of brain herniation within 24 hours, if not promptly diagnosed and treated.

HACE generally occurs after 2 days above 4000m but can occur at lower elevations (2500m) and with faster onset. Some, but not all, individuals will suffer from symptoms of AMS such as headache, insomnia, anorexia, nausea prior to transitioning to HACE. Some may also have concomitant High Altitude Pulmonary Oedema (HAPE). HACE in isolation is rare, but the absence of concomitant HAPE or symptoms of AMS prior to deterioration does not rule-out the presence of HACE.

Most cases develop as a progression of AMS and will include a history of recent ascent to altitude and prior complaints/findings of AMS including a headache, fatigue, nausea, insomnia, and/or light-headedness. Some may also have signs/symptoms of HAPE. Transition to HACE is heralded by signs of encephalopathy including ataxia (usually the earliest clinical finding) and altered mentation which may range from mild to severe. Other symptoms may include a more severe headache, difficulty speaking, lassitude, a decline in the level of consciousness, and/or focal neurological deficits or seizures.

The mainstay of treatment is the immediate descent of at least 1000m or until symptoms improve. If descent is not an option, one may use a portable hyperbaric chamber and/or supplemental oxygen to temporize illness, but this should never replace or delay evaluation/descent when possible. If available, dexamethasone 8mg for one dose, followed by 4mg every 6 hours should be given to adults via PO, IM, or IV routes.
Acetazolamide has proven to be beneficial in only a single clinical study. The suggested dosing regimen for Acetazolamide is 250 mg PO, given twice daily. Though effective in alleviating or temporizing symptoms, none of the adjunct treatment modalities are definitive or a replacement for an immediate descent.

The patient’s history of recent weight loss and malaise, paired with enlarged kidneys and renal failure, as well as a suspected central pelvic mass on ultrasound, gives a suspicion of cervical carcinoma.

Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

The most probable diagnosis considering hypochloraemia and the mild metabolic alkalosis as well as the history of GERD (requiring a high dose of PPI to control) would be bulimia.

Other options:
Diuretic abuse tends to give a hypochloraemic acidosis.
Gitelman syndrome also fits the diagnosis but, it is very rare compared to bulimia.
Inhaled steroid use and stress would not be responsible for such marked electrolyte derangement.

Other potential signs of bulimia nervosa would be parotid gland swelling and dental enamel erosion induced by regular vomiting.

There are five prognostic factors which indicate poor prognosis in HOCM:
-family history of HOCM-related sudden cardiac death
-unexplained recent syncope
-large left ventricular wall thickness (MLVWT ≥ 30 mm)
-multiple bursts of nsVT on ambulatory electrocardiography
-hypotensive or attenuated blood pressure response to exercise

Molluscum contagiosum (MC), is a viral infection of the skin that results in small, raised, pink lesions with a dimple in the center with little to no surrounding erythema. They may occasionally be itchy or sore. They may occur singularly or in groups. Any area of the skin may be affected, with abdomen, legs, arms, neck, genital area, and face being most common. Onset of the lesions is around 7 weeks after infection. It usually goes away within a year without scarring.
Chickenpox lesions in the early stages may be mistaken for molluscum. However, the presence of associated macules and later vesicles and pustules help to differentiate them.

Patients with active cancer are at a continuous risk of having venous thromboembolism (VTE), such as DVT. Therefore, a six-month course of an anticoagulant such as LMWH is recommended. LMWH is the drug of choice since its side effects can be reversed and it can be stopped easily in case of a cancer-related bleed, for example, massive haemoptysis in a patient with lung cancer.

An escharotomy is a surgical procedure used to treat full-thickness (third-degree) circumferential burns. In full-thickness burns, both the epidermis and the dermis are destroyed along with sensory nerves in the dermis. The tough leathery tissue remaining after a full-thickness burn has been termed eschar.

Excessive sweating points towards a morphine overdose.

Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.
Most commonly used in pain management, morphine provides major relief to patients afflicted with pain.

Among the more common adverse effects of morphine use is constipation. Other side effects include nausea, vomiting, drowsiness, and confusion. Psychological and physical dependence may occur.

Other side effects include bronchospasm, angioedema, urinary retention, ureteric or biliary spasm, dry mouth, sweating, rash, facial flushing, vertigo, tachycardia, bradycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, mood change, hallucinations, seizures (adults and children) and miosis, headache and allergic reactions (including anaphylaxis) and decreased libido or potency.

Raised intracranial pressure occurs in some patients. Muscle rigidity may occur with high doses. Elevated liver enzymes may occur due to biliary sphincter constriction. Large doses can lead to respiratory depression, circulatory failure, and coma.

Treatment of opioid overdose:
Initial treatment of overdose begins with supportive care.
Naloxone is a pure competitive antagonist of opiate receptors and has no agonistic activity. The drug is relatively safe and can be administered intravenous, intramuscular, subcutaneous or via the endotracheal tube.
Alternatively, nalmefene and naltrexone maybe considered.

Hypertrophic cardiomyopathy is an autosomal dominant condition. Patients present with sudden cardiac death, dyspnoea, syncope and presyncope, angina, palpitations, orthopnoea and paroxysmal nocturnal dyspnoea, Congestive heart failure and dizziness. Physical findings include double or triple apical impulse, prominent a wave in the JVP, an ejection systolic crescendo-decrescendo murmur and a holosystolic murmur at the apex and axilla of mitral regurgitation.
ECG shows ST-T wave abnormalities and LVH, axis deviation (right or left), conduction abnormalities (P-R prolongation, bundle-branch block), sinus bradycardia with ectopic atrial rhythm, atrial enlargement, abnormal and prominent Q wave in the anterior precordial and lateral limb leads.
2D echocardiography shows abnormal systolic anterior leaflet motion of the mitral valve, LVH, left atrial enlargement, small ventricular chamber size, septal hypertrophy with septal-to-free wall ratio greater than 1.4:1, mitral valve prolapse and mitral regurgitation, decreased midaortic flow, partial systolic closure of the aortic valve in midsystole

This girl most probably has Turner’s syndrome, which is caused by the absence of one set of genes from the short arm of one X chromosome.
Turner syndrome is a lifelong condition and needs lifelong oestrogen replacement therapy. Oestrogen is usually started at age 12-15 years. Treatment can be started with continuous low-dose oestrogens. These can be cycled in a 3-weeks on, 1-week off regimen after 6-18 months; progestin can be added later.

In childhood, growth hormone therapy is standard to prevent short stature as an adult.

Fetal ovarian development seems to be normal in Turner syndrome, with degeneration occurring in most cases around the time of birth so pulsatile GnRH and luteinising hormone would be of no use.

Given that the patient has had large amount, high volume watery diarrhoea in an acute period of time, from the answer choices given, this narrows the diagnosis down to VIPoma or carcinoid syndrome. You would expect with carcinoid syndrome for there to be periodic episodes of diarrhoea, though, with a description of flushing, additionally, associated with these episodes. Thus, VIPoma is the most likely answer here. VIPomas are known to cause hypokalaemia from this large amount of watery diarrhoea. Stool volume should be > 700 ml/day.

The SEM is dependent on the variation in the population and the number of the extracted samples. A large variation in the population causes a large difference in the sample means, ultimately resulting in a larger SEM. However, as more samples are extracted from the population, the sample means move closer to the population mean, which results in a smaller SEM. In short, the SEM is an indicator of how close the sample mean is to the population mean. Standard error of the mean = standard deviation / square root (number of patients)
The standard error of the mean is calculated by the standard deviation / square root (number of patients)

= 12 / square root (64) = 12 / 8 = 1.5

Insulin/dextrose infusion will increase the activity of the sodium-potassium pump in the cells, which will in turn decrease serum potassium levels.

Haemophilia is a X-linked recessive disorder. In X-linked recessive inheritance only males are affected. An exception to this seen in examinations are patients with Turner’s syndrome, who are affected due to only having one X chromosome. X-linked recessive disorders are transmitted by heterozygote females (carriers) and male-to-male transmission is not seen. Affected males can only have unaffected sons and carrier daughters.