The most common type of Hodgkin’s lymphoma (HL) is nodular sclerosing.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

According to the histological classification, there are four types of HL:

1. Nodular sclerosing: most common (around 70%), more common in women, associated with lacunar cells, good prognosis

2. Mixed cellularity: Around 20%, associated with a large number of Reed-Sternberg cells, good prognosis

3. Lymphocyte-predominant: Around 5%, Reed-Sternberg cells with nuclei surrounded by a clear space found, best prognosis

4. Lymphocyte-depleted: rare, worst prognosis

According to the US immunisation schedule, the child is immunised. So this boy does not need any extra immunisation for tetanus now.

Mechanism of action of low molecular weight heparin (LMWH):
It inhibits coagulation by activating antithrombin III. Antithrombin III binds to and inhibits factor Xa. In doing so it prevents activation of the final common path; Xa inactivation means that prothrombin is not activated to thrombin, thereby not converting fibrinogen into fibrin for the formation of a clot.

LMHW is a small fragment of a larger mucopolysaccharide, heparin. Heparin works similarly, by binding antithrombin III and activating it. Heparin also has a binding site for thrombin, so thrombin can interact with antithrombin III and heparin, thus inhibiting coagulation.
Heparin has a faster onset of anticoagulant action as it will inhibit not only Xa but also thrombin, while LMWH acts only on Xa inhibition.

Compared to heparin, LMWHs have a longer half-life, so dosing is more predictable and can be less frequent, most commonly once per day.

Dosage and uses:
LMWH is administered via subcutaneous injection. This has long-term implications on the choice of anticoagulant for prophylaxis, for example, in orthopaedic patients recovering from joint replacement surgery, or in the treatment of DVT/PE.

Adverse effects:
The main risk of LMWH will be bleeding. The specific antidote for heparin-induced bleeding is protamine sulphate.
Less commonly it can cause:
Heparin-induced thrombocytopenia (HIT)
Osteoporosis and spontaneous fractures
Hypoaldosteronism
Hypersensitivity reactions

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).

Hepatitis C is a single-stranded positive sense RNA virus. It is variable because of the high rate of error of RNA-dependent RNA polymerase and the pressure from the host immune system has caused HCV to evolve and develop seven genetic lineages.

Agitation, hypomania and suicidal intent within a few days after initiating corticosteroid therapy is highly suggestive of a diagnosis of corticosteroid-induced psychosis.

In some patients corticosteroid related psychosis has been diagnosed up to 12 weeks or more after commencing therapy.

Euphoria and hypomania are considered to be the most common psychiatric symptoms reported during short courses of steroids.
During long-term treatment, depressive symptoms were the most common.
Higher steroid doses appear to carry an increased risk for such adverse effects; however, there is no significant relationship between dose and time to onset, duration, and severity of symptoms.

Management: Reduction or cessation of corticosteroids is the mainstay of treatment for steroid psychosis. For those patients who cannot tolerate this reduction/cessation of steroids, mood stabilizers may be of some benefit.

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

Permanent pacing is not indicated as the bradycardia is reversible. Temporary pacing is the definite treatment. Isoprenaline can be used until temporary pacing is available.

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered. For patients at low risk of these symptoms, drugs such as metoclopramide may be used. For high-risk patients, however, 5-HT3 receptor antagonists such as ondansetron are often effective, especially if combined with dexamethasone.

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.

Infections of the superficial skin around the eyes are called periorbital, or preseptal, cellulitis. It is predominantly a paediatric disease. Erysipelas is a bacterial skin infection involving the upper dermis which extends into the superficial cutaneous lymphatics. Sinusitis is in sinuses. Orbital infections and conjunctivitis are within the eye.

Anorexia nervosa is an eating disorder characterized by an abnormally low body weight, an intense fear of gaining weight and a distorted perception of weight. People with anorexia place a high value on controlling their weight and shape, using extreme efforts that tend to significantly interfere with their lives.

The minimum level of severity is based, for adults, on current body mass index (BMI) (see below) or for
children and adolescents, on BMI percentile. The ranges below are derived from World Health
Organization categories for thinness in adults; for children and adolescents, corresponding BMI percentiles
should be used. The level of severity may be increased to reflect clinical symptoms, the degree of
functional disability, and the need for supervision.
Mild: BMI > 17 kg/m2
Moderate: BMI 16-16.99 kg/m2
Severe: BMI 15-15.99 kg/m2
Extreme: BMI < 15 kg/m2 Anorexia nervosa is more common in women than in men, with a female-to-male ratio of 10-20:1 in developed countries. The prognosis of anorexia nervosa is guarded. Morbidity rates range from 10-20%, with only 50% of patients making a complete recovery. Of the remaining 50%, 20% remain emaciated and 25% remain thin. The main change in the diagnosis of Anorexia Nervosa was to remove the criterion of amenorrhea (loss of menstrual cycle). Removing this criterion means that boys and men with Anorexia will finally be able to receive an appropriate diagnosis.
Similarly, girls and women who continue to have their period despite other symptoms associated with Anorexia, such as weight loss and food restriction, will now be eligible for a diagnosis of Anorexia.

The most likely diagnosis is hypertrophic obstructive cardiomyopathy which is suggestive by the history, positive family history and ECG findings. Two-dimensional echocardiography is diagnostic for hypertrophic cardiomyopathy. In general, a summary of echocardiography findings includes abnormal systolic anterior leaflet motion of the mitral valve, LV hypertrophy, 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, and partial systolic closure of the aortic valve in midsystole.

A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.

Hypertension and haematuria are not common presentations in minimal change glomerulonephritis, all other statements are correct.

Type I pneumocyte: The cell responsible for the gas (oxygen and carbon dioxide) exchange that takes place in the alveoli. It is a very thin cell stretched over a very large area. This type of cell is susceptible to a large number of toxic insults and cannot replicate itself.
Type II pneumocyte: The cell responsible for the production and secretion of surfactant (the molecule that reduces the surface tension of pulmonary fluids and contributes to the elastic properties of the lungs). The type 2 pneumocyte is a smaller cell that can replicate in the alveoli and will replicate to replace damaged type 1 pneumocytes. Alveolar macrophages are the primary phagocytes of the innate immune system, clearing the air spaces of infectious, toxic, or allergic particles that have evaded the mechanical defences of the respiratory tract, such as the nasal passages, the glottis, and the mucociliary transport system. The main role of goblet cells is to secrete mucus in order to protect the mucous membranes where they are found. Goblet cells accomplish this by secreting mucins, large glycoproteins formed mostly by carbohydrates.

There is a strong suspicion of drug-induced acute tubulo-interstitial nephritis with the classic triad of symptoms of rash, joint pain and eosinophils in the blood, associated with non-specific symptoms of fever and fatigue. This can be confirmed with renal biopsy showing interstitial oedema with a heavy infiltrate of inflammatory cells and variable tubular necrosis.

Elderly patients with severe hypothyroidism often present with variable symptoms that may be masked or potentiated by co-morbid conditions. Characteristic symptoms may include fatigue, weight gain, cold intolerance, hoarseness, constipation, and myalgias. Neurologic symptoms may include ataxia, depression, and mental status changes ranging from mild confusion to overt dementia.
Clinical findings that may raise suspicion of thyroid hormone deficiency include hypothermia, bradycardia, goitrous enlargement of the thyroid, cool dry skin, myxoedema, delayed relaxation of deep tendon reflexes, a pericardial or abdominal effusion, hyponatremia, and hypercholesterolemia.

The patient has a greatly reduced free T4 concentration, is hypothermic, unconscious and has evidence of associated heart failure. All of those support the diagnosis of profound hypothyroidism.

Polymyositis is an inflammatory disorder causing symmetrical, proximal muscle weakness. It is thought to be a T-cell mediated cytotoxic process directed against muscle fibres. It may be idiopathic or associated with connective tissue disorders. It may also be associated with malignancy for example small cell lung carcinoma.
Dermatomyositis is a variant of the disease where skin manifestations are prominent, for example a purple (heliotrope) rash on the cheeks and eyelids.
It typically affects middle-aged, female: male 3:1. Features include proximal muscle weakness +/- tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease: e.g. fibrosing alveolitis or organising pneumonia, dysphagia, dysphonia. Investigations: elevated creatine kinase, other muscle enzymes (lactate dehydrogenase (LD), aldolase, AST and ALT) are also elevated in 85-95% of patients, EMG, muscle biopsy. Anti-Jo-1 antibodies are seen in pattern of disease associated with lung involvement, Raynaud’s and fever. Interstitial lung disease plays a major role in morbidity and mortality in patients with polymyositis and is considered a major risk factor for premature death in patients with myositis.

Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.

Ethylene glycol is a type of alcohol used as a coolant or antifreeze
Features of toxicity are divided into 3 stages:
Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)
Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertension
Stage 3: (24 – 72 hours after exposure) Acute renal failure

Management has changed in recent times:
Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.
Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.
Haemodialysis has a role in refractory cases.

Aprepitant is an anti-emetic which blocks the neurokinin 1 (NK1) receptor and acts as a substance P antagonist. It is licensed for chemotherapy-induced nausea and vomiting (CINV) and for prevention of postoperative nausea and vomiting.

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered.

This man has a small-cell lung cancer (SCLC) and associated Lambert-Eaton myasthenic syndrome – a well-recognized paraneoplastic manifestation of SCLC. This classically affects the proximal muscles, especially in the legs, causing difficulty in standing from a seated position and climbing stairs. In contrast to myasthenia gravis, eye involvement is uncommon. Treatment with steroids is often helpful, which explains his transient symptomatic improvement during treatment for his COPD exacerbation. Steroid myopathy does not fit as the symptoms started well before his course of prednisolone. Although the patient is mildly hypercalcaemic, this would not be sufficient to produce his presenting symptoms, although it does reinforce the suspicion of lung malignancy. Motor neurone disease would be unlikely in this context and would not improve with steroids. Myasthenia gravis could produce these symptoms, but in the context of a new lung mass is a less viable diagnosis.

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 following are conditions commonly associated with pyoderma gangrenosum:
Inflammatory bowel disease:
– Ulcerative colitis
– Crohn’s disease
Arthritides:
– Rheumatoid arthritis
– Seronegative arthritis
Haematological disease:
– Myelocytic leukaemia[8]
– Hairy cell leukaemia
– Myelofibrosis
– Myeloid metaplasia
– Monoclonal gammopathy
Autoinflammatory disease:
– Pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome (PAPA syndrome)
– Granulomatosis with polyangiitis

The most common causes of a sudden painless loss of vision are:
– ischaemic optic neuropathy
– occlusion of central retinal vein or artery
– vitreous haemorrhage
– retinal detachment.
Central retinal artery occlusion is due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis). Features include afferent pupillary defects, and a ‘cherry red’ spot on a pale retina.

This case presents with symptoms and lab results suggestive of uremic pericarditis, which is an indication for immediate haemodialysis. Uremic pericarditis is caused by inflammation of the membranes of the pericardial sac, which usually resolves after a period of intensive dialysis.

The prompt is suggestive of acute appendicitis. The Alvarado score is a clinical scoring system used to determine the likelihood of appendicitis, so this is the correct answer. A score greater than 6 is generally considered at risk for having acute appendicitis. It has 8 different criteria included (symptoms, signs, and lab results) and divides patients into appendicitis unlikely, possible, probable, and definite. The Center Score is a score to access the likelihood that pharyngitis is due to Strep. The Child-Pugh score predicts prognosis in liver cirrhosis. The Glasgow score is two different scores– the Glasgow coma score in trauma, which estimates level of consciousness, essentially, and The Glasgow Imrie Criteria which determines the severity of acute pancreatitis based on 8 lab values. The MELD score predicts the severity of end-stage liver disease.

The diagnosis is inferior ST elevation myocardial infarction. As the right coronary artery supplies the SA and AV nodes and bundle of His, conduction abnormalities are more common with inferior MIs. The most immediate drug management is high dose Aspirin. Definite treatment is urgent cardiac revascularization.

Rheumatoid arthritis is a polyarthritis that results in symmetrical pain and swelling of the affected joints (also at rest). It particularly affects the metacarpophalangeal joints (MCPJs) and proximal interphalangeal joints (PIPJs), not the distal interphalangeal joints (DIPs).
Ulcerative colitis and IBD are associated with seronegative arthritides, not RA. The condition can also cause various extra-articular manifestations such as ocular symptoms, rheumatoid nodules and pulmonary fibrosis. Scleritis, episcleritis and keratoconjunctivitis sicca are more common than uveitis. Early intervention with disease-modifying antirheumatic drugs (DMARDs) plays a decisive role in successful treatment.

The typical “rheumatoid effusion” is a sterile exudative fluid with low pH (<7.3), low glucose (<60 mg. dL−1) and elevated lactate dehydrogenase (may be >700 IU). It should initially be treated with NSAIDs. Decortication should be reserved in patients with thickened pleura who have symptomatic dyspnoea.