Bombesin is a tumour marker elevated in small cell lung carcinomas, as well as in gastric carcinomas and retinoblastomas.

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)

Long-term oxygen therapy (LTOT) ≥ 15 h/day improves survival in hypoxemic chronic obstructive pulmonary disease (COPD). It significantly helps in reducing pulmonary hypertension associated with COPD and treating underlying pathology of future heart failure. There is little to no benefit of oxygen therapy for less than 15 hours.

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.

Macular disease can affect central vision at any stage of diabetic retinopathy and may be seen in type 2 diabetic patients. Diabetic retinopathy affects up to 80 percent of those who have had diabetes for 20 years or more. Macular oedema occurs when damaged blood vessels leak fluid and lipids onto the macula, the part of the retina that lets us see detail. The fluid makes the macula swell, which blurs vision.

Fundoscopy findings of cotton wool spots and retinal tears, accompanied by a history of blurred vision, are characteristic of retinitis. Cytomegalovirus is known to cause retinitis.

The principal mechanism of action of taxanes (e.g. docetaxel) is the prevention of microtubule disassembly.

Other aforementioned options are ruled out because:

1. Doxorubicin: stabilizes DNA topoisomerase II complex and inhibits DNA and RNA synthesis.

2. Vincristine, vinblastine: inhibits formation of microtubules.

3. Cisplatin: causes cross-linking in DNA.

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.

Renal elimination of a drug has no role in altering the bioavailability of a drug.
The bioavailability of a drug is the proportion of the drug which reaches systemic circulation.
Mathematically, bioavailability is the AUCoral/AUCiv x 100%, where AUC = area under the concentration-time curve following a single (oral or iv) dose.

Other options are true:
By definition, the bioavailability of a drug given intravenously is 100%.
Drugs given orally that undergo high pre-systemic (first-pass) metabolism in the liver or gut wall have a low bioavailability e.g. lidocaine.
Bioavailability is also affected by the degree of absorption from the gut and this can change depending on gut motility and administration of other drugs.

Liddle’s Syndrome is an autosomal dominant disorder that presents with hypertension usually in young patients, that do not respond to anti-hypertensive therapy and is later associated with hypokalaemia, low renin plasma, and low aldosterone levels as well. The other conditions listed do not present with hypertension and associated hypokalaemia.

The dose is calculated, using the conversion factor, as follows:

(Conversion factor used to convert oral morphine to subcutaneous diamorphine = Divide the total daily dose of oral morphine by 3)
Hence,
60mg*2 = 120mg
120mg/3 = 40mg

The side effects of opioids can be transient or persistent, and these include constipation, nausea, and drowsiness. Therefore, all patients taking opioids should also be prescribed a laxative and an anti-emetic (if the nausea is persistent). Dose-adjustment may be necessary in cases of persistent drowsiness. Moreover, strong opioids can also provide quick relief from metastatic bone pain, as compared to NSAIDs, bisphosphonates, and radiotherapy.

The latest research recommends that simple tooth extraction in patients on warfarin treatment can be performed safely without high risk of bleeding, providing that the INR is equal to or less than 3.5 on the day of extraction. A close follow-up and monitoring of patients taking warfarin is mandatory after dental extraction.

The hazard ratio describes the relative risk of the complication based on comparison of event rates.

Hazard ratios have also been used to describe the outcome of therapeutic trials where the question is to what extent treatment can shorten the duration of the illness. However, the hazard ratio, a type of relative risk, does not always accurately portray the degree of abbreviation of the illness that occurred. In these circumstances, time-based parameters available from the time-to-event curve, such as the ratio of the median times of the placebo and drug groups, should be used to describe the magnitude of the benefit to the patient. The difference between hazard-based and time-based measures is analogous to the odds of winning a race and the margin of victory. The hazard ratio is the odds of a patient’s healing faster under treatment but does not convey any information about how much faster this event may occur.

The patient is most likely complaining of the effects of hyperkalaemia, due to missing his dialysis sessions. Additionally, because the patient presents with a risk of cardiac arrest (based on pulmonary oedema and ECG findings), the best intervention is to give calcium gluconate that will address the hyperkalaemia as well as improve the cardiac condition.

From the given history the patient has NYHA grade III heart failure. He can be safely started on an ACE inhibitor as his serum potassium was towards the lower limit. As there an impairment of renal function, his urea, creatinine and serum electrolytes should be closely monitored after commencing an ACE inhibitor. Adding atenolol will not have any clinical benefit. Increasing the digoxin dose is not needed as the patient is in sinus rhythm. Increasing furosemide will only have symptomatic relief.

CURB Pneumonia Severity Score estimates the mortality of community-acquired pneumonia to help determine inpatient vs. outpatient treatment.
Select Criteria:
Confusion (abbreviated Mental Test Score <=8) (1 point)
Urea (BUN > 19 mg/dL or 7 mmol/L) (1 point)
Respiratory Rate > 30 per minute (1 point)
Blood Pressure: diastolic < 60 or systolic < 90 mmHg (1 point) The CURB-65 scores range from 0 to 5. Clinical management decisions can be made based on the score:
Score Risk Disposition
0 or 1 – 1.5% mortality – Outpatient care
2 – 9.2% mortality – Inpatient vs. observation admission
≥ 3 – 22% mortality – Inpatient admission with consideration for ICU admission with score of 4 or 5

Carcinoembryonic antigen (CEA) is a known tumour marker for colorectal cancer. It is not used diagnostically, but in patients with a known diagnosis of colorectal cancer associated with raised CEA levels, it can be used to monitor disease activity and help with the early identification of disease recurrence.

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)

Given the symptoms described in a 31-year-old homosexual male, along with the findings of weight loss, blurred vision, and retinal hemorrhage, the single most appropriate option to consider is HIV/AIDS.

HIV/AIDS can manifest with a wide range of symptoms, including unintentional weight loss and blurred vision. Retinal hemorrhage can also occur as a complication of HIV/AIDS, particularly in advanced stages when the immune system is severely compromised.

In this case, it’s important to conduct further diagnostic tests, including HIV testing, to confirm the diagnosis. Additionally, prompt initiation of antiretroviral therapy (ART) is crucial for managing HIV/AIDS and preventing further complications. Referral to an infectious disease specialist for comprehensive management is recommended.

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.

Funnel plots are graphical tools to assess and compare clinical performance of a group of care professionals or care institutions on a quality indicator against a benchmark. Incorrect construction of funnel plots may lead to erroneous assessment and incorrect decisions potentially with severe consequences.

Café-au-lait spots is hyperpigmented lesions that vary in colour from light brown to dark brown, with borders that may be smooth or irregular. Causes include:
Neurofibromatosis type I
McCune–Albright syndrome
Legius syndrome
Tuberous sclerosis
Fanconi anaemia
Idiopathic
Ataxia-telangiectasia
Basal cell nevus syndrome
Benign congenital skin lesion
Bloom syndrome
Chediak-Higashi syndrome
Congenital nevus
Gaucher disease
Hunter syndrome
Maffucci syndrome
Multiple mucosal neuroma syndrome
Noonan syndrome
Pulmonary Stenosis
Silver–Russell syndrome
Watson syndrome
Wiskott–Aldrich syndrome

According to the American Heart Association (AHA) penicillin-susceptible S viridans, S bovis, and other streptococci (MIC of penicillin of ≤0.1 mcg/mL) should be treated with penicillin G or ceftriaxone or penicillin G + a gentamicin combination or vancomycin (if allergy to penicillin).

The chance of two carriers of a recessive gene having a child that is homozygous for that disease (that is both genes are transmitted to the child) is 25%. Therefore, the chances of this couple having a child with CF are 25%(1/4) x 1/20 = 1/80.

Confusion in the patient refers to neurological symptoms that are more associated with thrombotic thrombocytopenic purpura than with haemolytic uremic syndrome. All the other symptoms present in both conditions similarly.

This question describes Charcot’s triad– fever, RUQ pain, and jaundice, which is seen in ascending cholangitis. Reynold’s pentad is a worsened version of this, where you have RUQ pain, fever, jaundice, hypotension, and altered mental status. Risk factors for gallstones are the 4F’s- female, fat, forty, and fertile. You would not have the elevated bilirubin, ALP, transaminases with a kidney stone or in peptic ulcer disease. Hepatitis would not cause elevation of bilirubin.

Anti-TNF-α therapy is effective for patients with arthritis but it can oftentimes lead to the reactivation of latent TB. Hence it should be used with great caution in patients with a past history of TB or current infection.

Hypersegmented neutrophils in the peripheral blood film is suggestive of megaloblastic changes in bone marrow.

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.

This patient has complaints of diplopia in the right eye, when looking towards the right. Eyeball movements towards the right side are controlled by right lateral rectus muscle which is supplied by the abducent nerve.

The diagnosis of polycystic ovarian syndrome (PCOS) is based on hyperandrogenism or chronic anovulation in the absence of specific pituitary and/or adrenal disease.
Pelvic ultrasonography may be very helpful in the evaluation as well, but polycystic ovaries are not specific for PCOS with over 20% of “normal” women having this finding. The number of follicles and ovary volume are both important in the ultrasound evaluation. The criteria for PCOS put forth by Adams et al. are the most often cited: the presence of ≥10 cysts measuring 2–8 mm around a dense core of stroma or scattered within an increased amount of stroma.
A recent proposal to modify these criteria has been put forth by Jonard et al.: “increased ovarian area (>5.5cm2) or volume (>11 mL) and/or presence of ≥12 follicles measuring 2 to 9 mm in diameter (mean of both ovaries)”.
These criteria have a specificity of 99% and a sensitivity of 75% for the diagnosis of PCOS.

Vitamin A toxicity is a rare cause of papilledema. In this case, the patient is likely to have been taking retinoids for psoriasis.

Encephalitis does not usually present with papilledema. Brain abscess, brain tumour and hydrocephalus are all less likely with a normal CT head.