Right ventricular volume overload is indicated by a parasternal heave and right axis deviation. Oxygen saturation in right atrium is higher than oxygen saturation of the inferior and superior vena cavae. So the most probable diagnosis is atrial septal defect.

Intestinal phosphate absorption is mediated by both transcellular and paracellular routes. The 1,25(OH)2D increases intestinal transcellular phosphate absorption at least in part by enhancing expression of type 2b sodium–phosphate cotransporter, thus increasing plasma phosphate.

The woman seems to have a chancroid, which may or may not drain to the lymph nodes of the groin. These nodes are the superficial inguinal lymph nodes.

Herpes zoster is a viral disorder in which painful vesicular lesions are present in a specific dermatome area. High-grade fever may present as well due to infection. Varicella zoster, measles, herpes simplex and HIV do not present with tender lesions of a limited area.

According to different guidelines for patients above 80 years, the targeted systolic blood pressure varies from 140-150 mmHg. As this patient’s BP is within that range, he can be kept under observation.

The antithrombotic action of aspirin is due to inhibition of platelet function by acetylation of the platelet cyclooxygenase (COX) at the functionally important amino acid serine529. This prevents the access of the substrate (arachidonic aid) to the catalytic site of the enzyme at tyrosine385 and results in an irreversible inhibition of platelet-dependent thromboxane formation.

The number needed to treat (NNT) is valuable information in treatment decisions. NNT is the inverse of the absolute risk reduction (1/ARR) between two treatment options.

Burkitt lymphoma is a germinal centre B-cell-derived cancer that was instrumental in the identification of MYC as an important human oncogene more than three decades ago. Recently, new genomics technologies have uncovered several additional oncogenic mechanisms that cooperate with MYC to create this highly aggressive cancer.

The number needed to treat (NNT) is valuable information in treatment decisions. NNT is the inverse of the absolute risk reduction (1/ARR) between two treatment options. Control event rate = 10 / 50 = 0.2
Experimental event rate = 18 / 120 = 0.15

Absolute risk reduction = 0.2 – 0.15 = 0.05
Number needed to treat = 1 / 0.05 = 20

Activated charcoal is useful if given within one hour of the paracetamol overdose. Liver function tests, INR and prothrombin time will be normal, as liver damage may not manifest until 24 hours or more after ingestion.

The antidote of choice is intravenous N-acetylcysteine, which provides complete protection against toxicity if given within 10 hours of the overdose.

The diagnosis for the aforementioned case is thrombotic thrombocytopenic purpura (TTP). TTP is classically characterised as a pentad of thrombocytopaenia, microvascular haemolysis, fluctuating neurological signs, renal impairment, and fever.

The differential diagnosis for severe thrombocytopaenia is immune thrombocytopenic purpura (ITP). ITP is more common than TTP. However, a patient of ITP would not present with the range of symptoms seen in this scenario.

In TTP, there is deficiency of a protease which breaks down large multimers of von Willebrand factor. This leads to abnormally large and sticky multimers of von Willebrand factor which cause platelets to clump within the vessels.

Untreated TTP has a mortality rate of up to 90%. Therefore, rapid plasma exchange (PEX) may be a life-saving intervention. Platelet transfusion in TTP is only indicated if there is an ongoing life-threatening bleed. Intravenous methylprednisolone is indicated after treatment with PEX has been completed. There is no current role of intravenous immunoglobulin in the routine management of TTP. However, there have been reports of its successful use in PEX- and steroid-refractory cases. Intravenous argatroban is indicated in heparin-induced thrombocytopaenia (HIT), but there is no history of recent heparin administration or hospitalisation in this patient nor are the clinical signs consistent with HIT.

Management options for TTP include PEX as the treatment of choice. Steroids and immunosuppressants are also given. Antibiotics are not recommended as they may worsen the outcome of the disease. For cases resistant to PEX and pharmacologic therapy, vincristine is given.

The cause of Vitiligo is typically unknown. It is believed to be due to genetic susceptibility that is triggered by an environmental factor such that an autoimmune disease occurs. This results in the destruction of skin pigment cells. Risk factors include a family history of the condition or other autoimmune diseases, such as hyperthyroidism, alopecia areata, and pernicious anaemia. Vitiligo is classified into two main types: segmental and non-segmental. Most cases are non-segmental meaning they affect both sides and typically get worse with time. The prevalence of vitiligo is 0.5-1% of populations worldwide. Typical sites include backs of hands, wrists, knees, neck and around body orifices. The Koebner phenomenon refers to skin lesions appearing on lines of trauma. This occurs in vitiligo secondary to scratching.

With biliary obstructive symptoms in a patient with ulcerative colitis, one should immediately think of primary sclerosing cholangitis (PSC). PSC is characterized by inflammation and fibrosis of the intrahepatic and extrahepatic ducts. The best diagnostic test for PSC is ERCP. ANCA antibiotics may be positive, but not the best test to DIAGNOSE THE CONDITION. The same can be said of serum transaminase levels– they will be abnormal but nonspecific. While a liver ultrasound may be helpful, it is not the best test. Liver biopsy would be used to stage the PSC later.

This child has pseudo hypoparathyroidism. It is a heterogeneous group of rare endocrine disorders characterized by normal renal function and resistance to the action of parathyroid hormone (PTH), manifesting with hypocalcaemia, hyperphosphatemia, and increased serum concentration of PTH.
Patients with pseudo hypoparathyroidism type 1a present with a characteristic phenotype collectively called Albright hereditary osteodystrophy (AHO). The constellation of findings includes the following:
Short stature
Stocky habitus
Obesity
Developmental delay
Round face
Dental hypoplasia
Brachymetacarpals
Brachymetatarsals
Soft tissue calcification/ossification
The goals of therapy are to maintain serum total and ionized calcium levels within the reference range to avoid hypercalcaemia and to suppress PTH levels to normal. This is important because elevated PTH levels in patients with PHP can cause increased bone remodelling and lead to hyper-parathyroid bone disease.
The goals of pharmacotherapy are to correct calcium deficiency, to prevent complications, and to reduce morbidity. Intravenous calcium is the initial treatment for all patients with severe symptomatic hypocalcaemia. Administration of oral calcium and 1alpha-hydroxylated vitamin D metabolites, such as calcitriol, remains the mainstay of treatment and should be initiated in every patient with a diagnosis of pseudo hypoparathyroidism.

The power of a test is defined as 1 − the probability of Type II error. The Type II error is concluding at no difference (the null is not rejected) when in fact there is a difference, and its probability is named β. Therefore, the power of a study reflects the probability of detecting a difference when this difference exists. It is also very important to medical research that studies are planned with an adequate power so that meaningful conclusions can be issued if no statistical difference has been shown between the treatments compared. More power means less risk for Type II errors and more chances to detect a difference when it exists.

Here, the patient seems to be intolerant to standard metformin. In such cases, modified-release preparations is considered as the most appropriate next step.
There is some evidence that these produce fewer gastrointestinal side-effects in patients intolerant of standard-release metformin.

Metformin is a biguanide and reduces blood glucose levels by decreasing the production of glucose in the liver, decreasing intestinal absorption and increasing insulin sensitivity.
Metformin decreases both the basal and postprandial blood glucose.
Other uses: In Polycystic Ovarian Syndrome (PCOS), Metformin decreases insulin levels, which then decreases luteinizing hormone and androgen levels. Thus acting to normalize the menstruation cycle.

Note:
Metformin is contraindicated in patients with severe renal dysfunction, which is defined as a glomerular filtration rate (GFR) less than 30 ml/min/1.732m2.
Metformin overdose has been associated with hypoglycaemia and lactic acidosis, for this reason, it has a black box warning for lactic acidosis.

This patient has polycystic ovarian syndrome (PCOS). Medical management of PCOS is aimed at the treatment of metabolic derangements, anovulation, hirsutism, and menstrual irregularity.
First-line medical therapy usually consists of an oral contraceptive to induce regular menses. The contraceptive not only inhibits ovarian androgen production but also increases sex hormone-binding globulin (SHBG) production. The American College of Obstetricians and Gynaecologists (ACOG) recommends the use of combination low-dose hormonal contraceptive agents for long-term management of menstrual dysfunction.
If symptoms such as hirsutism are not sufficiently alleviated, an androgen-blocking agent may be added. Pregnancy should be excluded before therapy with oral contraceptives or androgen-blocking agents are started.
First-line treatment for ovulation induction when fertility is desired is clomiphene citrate. Second-line strategies may be equally effective in infertile women with clomiphene citrate–resistant PCOS.

Bicarbonate therapy is not indicated in mild and moderate forms of DKA because metabolic acidosis will correct with insulin therapy. The use of bicarbonate in severe DKA is controversial due to a lack of prospective randomized studies. It is thought that the administration of bicarbonate may actually result in peripheral hypoxemia, worsening of hypokalaemia, paradoxical central nervous system acidosis, cerebral oedema in children and young adults, and an increase in intracellular acidosis. Because severe acidosis is associated with worse clinical outcomes and can lead to impairment in sensorium and deterioration of myocardial contractility, bicarbonate therapy may be indicated if the pH is 6.9 or less.

Age-related macular degeneration is the most common cause of blindness in the UK. Degeneration of the central retina (macula) is the key feature with changes usually bilateral. Smoking and genetic factors are risk factors for macular degeneration. The severity is divided into early, intermediate, and late types. The late type is additionally divided into dry and wet forms with the dry form making up 90% of cases.

Spironolactone is an aldosterone antagonist which acts in the distal convoluted tubule. It is a potassium-sparing diuretic that prevents the body from absorbing too much salt and keeps the potassium levels from getting too low. Spironolactone is used to treat heart failure, high blood pressure (hypertension), or hypokalaemia (low potassium levels in the blood).

This is a classic clinical presentation, with alcohol intake and nausea/vomiting that leads to hematemesis, of a Mallory-Weiss tear. In Mallory-Weiss tear, they typically present as a hemodynamically stable patient after a night of binge drinking and excessive resultant vomiting. Given his EGD did not show any other pathology and he is now stable, he can be discharged home.

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.

Leaking of cerebrospinal fluid from the dura is the most likely explanation for post-lumbar puncture headaches. It is thought that ongoing leak of cerebrospinal fluid (CSF) through the puncture site causes ongoing CSF loss, leading to low pressure. A post-LP headache is typically frontal or occipital and occurs within three days. It is normally associated with worsening on standing and improvement when lying down. Treatment in severe cases includes an epidural blood patch, but most resolve on their own.

Heterochromia (difference in iris colour) is seen in congenital Horner’s syndrome, as well as anhidrosis. Other features of non-congenital Horner’s include miosis, ptosis and enophthalmos.

When you have abnormal liver function tests after a cardiac arrest, the most likely aetiology, barring history that is known or given excluding this diagnosis, would be ischemia. Chronic alcohol abuse would not see an acute elevation like this. Hepatitis B is just unlikely given the clinical picture, ischemia is much more likely. The same is for Budd-Chiari syndrome (venous thrombosis) and Wilson’s disease.

The normal partial pressure reference values are: oxygen PaO2 more than 80 mmHg (11 kPa), and carbon dioxide PaCO2 lesser than 45 mmHg (6.0 kPa).
This patient has an elevated PaCO2 of 6.8kPa which exceeds the normal value of less than 6.0kPa.
The pH is also lower than 7.35 at 7.32

In any patient with asthma, an increasing PaCO2 indicates severe airway obstruction that is leading to respiratory muscle fatigue and patient exhaustion.

According to the British Thoracic Society guidelines:
Indications for admission to intensive care or high-dependency units include
patients requiring ventilatory support and those with acute severe or life-threatening asthma who are failing to respond to therapy, as evidenced by:
• deteriorating PEF
• persisting or worsening hypoxia
• hypercapnia
• arterial blood gas analysis showing fall in pH or rising hydrogen concentration
• exhaustion, feeble respiration
• drowsiness, confusion, altered conscious state
• respiratory arrest

Transfer to ICU accompanied by a doctor prepared to intubate if:
• Deteriorating PEF, worsening or persisting hypoxia, or hypercapnia
• Exhaustion, altered consciousness
• Poor respiratory effort or respiratory arrest

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.

The patient most likely has reactive arthritis which is usually diagnosed on history and clinical examination. The classic triad of symptoms include conjunctivitis, urethritis and arthritis. Arthritis and conjunctivitis may occur 4-6 weeks after a gastrointestinal or genitourinary infection. Arthritis usually occurs acutely, mostly involving the lower limb and is asymmetrical. Blood culture, urine culture and arthrocentesis (joint aspiration) will not yield positive results.

Cholecystokinin (CCK) was discovered in 1928 in jejunal extracts as a gallbladder contraction factor. It was later shown to be member of a peptide family, which are all ligands for the CCK1 and CCK2 receptors. CCK peptides are known to be synthetized in the small intestinal endocrine I-cells and cerebral neurons.

Chvostek and Trousseau signs can be elicited in patients with hypocalcaemia. Chvostek sign is the twitching of the upper lip with tapping on the cheek 2 cm anterior to the earlobe, below the zygomatic process overlying the facial nerve. Trousseau sign (a more reliable sign present in 94% of hypokalaemic individuals and only 1% to 4% of healthy people) is the presence of carpopedal spasm observed following application of an inflated blood pressure cuff over systolic pressure for 3 minutes in hypokalaemic patients.

Acute, symptomatic hypocalcaemia is treated with 10ml of 10% calcium gluconate over 10 minutes.