The patient presents with worsened renal condition from the last consultation when he was started on enalapril (an ACE inhibitor) so this medication should be stopped. Because there is also no fluid overload; furosemide, a diuretic, should also be stopped.

COPD is commonly associated with progressive hypoxemia. Oxygen administration reduces mortality rates in patients with advanced COPD because of the favourable effects on pulmonary hemodynamics.

Long-term oxygen therapy improves survival 2-fold or more in hypoxemic patients with COPD, according to 2 landmark trials, the British Medical Research Council (MRC) study and the US National Heart, Lung and Blood Institute’s Nocturnal Oxygen Therapy Trial (NOTT). Hypoxemia is defined as PaO2 (partial pressure of oxygen in arterial blood) of less than 55 mm Hg or oxygen saturation of less than 90%. Oxygen was used for 15-19 hours per day.

Therefore, specialists recommend long-term oxygen therapy for patients with a PaO2 of less than 55 mm Hg, a PaO2 of less than 59 mm Hg with evidence of polycythaemia, or cor pulmonale. Patients should be evaluated after 1-3 months after initiating therapy, because some patients may not require long-term oxygen.

Campylobacter is the most likely cause of diarrheal illness often due to undercooked meat being ingested. It is also a major cause of traveller’s diarrhoea. Sufficient fluid replacement and anti-emetics are indicated first followed by the antibiotic, Erythromycin although antibiotic treatment in adults is still in question. Ciprofloxacin and Tetracycline may also be effective.

Primary hyperparathyroidism (PHPT) is diagnosed based upon levels of blood calcium and parathyroid hormone (PTH). In most people with PHPT, both levels are higher than normal. Occasionally, a person may have an elevated calcium level and a normal or minimally elevated PTH level. Since PTH should normally be low when calcium is elevated, a minimally elevated PTH is considered abnormal and indicates PHPT.

Entrapment of the median nerve by pronator teres causes a median nerve neuropathy, which is worse during pronation of the forearm. Examination should involve excluding carpal tunnel syndrome and pronation of the affected forearm against resistance, which brings on the pain. Unlike carpal tunnel syndrome, the median nerve proximal to the wrist may be tender to palpation.

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. Dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum)

Arthritis mutilans is a rare (occurs in only 5% of the patients) and extremely severe form psoriatic arthritis characterized by resorption of bones and the consequent collapse of soft tissue. When this affects the hands, it can cause a phenomenon sometimes referred to as ‘telescoping fingers.’ The associated nail changes are also characteristic of arthritis.

Botulinum toxin is a neurotoxic protein from Clostridium botulinum that causes flaccid paralysis as it acts by preventing the release of Ach at the neuromuscular joint. It is the first-line treatment for cervical dystonia (torticollis) because the condition is a neurological disorder characterised by unusual muscle contractions of the neck. With the use of Botulinum toxin, the contractions would be released.

The patient is most likely to have Addison’s disease as he has a history of autoimmune disease, hyperkalaemia and hypotension.
It is important to keep an Addisonian crisis on the differential in cases of shock, especially since adrenal crisis can be the patient’s first presentation of adrenal insufficiency.
Patients with Addison’s disease are prone to developing hypoglycaemia due to loss of the glucogenic effect of glucocorticoids. Given the sudden deterioration, a glucose level must be checked.

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

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.

For medical management of carcinoid syndrome, there are two somatostatin analogues available, Octreotide and Lanreotide. Somatostatin is an amino acid peptide which is an inhibitory hormone, which is synthesized by paracrine cells located ubiquitously throughout the gastrointestinal tract. Both somatostatin analogues provide symptom relief in 50% to 70% of patients and biochemical response in 40% to 60% patients. Many studies have shown that Octreotide and Lanreotide also inhibit the proliferation of tumour cells.

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.

Prostate cancer is the most common primary tumour that metastasises to the bone.

Most common tumours causing bone metastasis (in descending order):
1. Prostate (32%)
2. Breast (22%)
3. Kidneys (16%)
4. Lungs
5. Thyroid

Most common sites of bone metastasis (in descending order):
1. Spine
2. Pelvis
3. Ribs
4. Skull
5. Long bones

The peak incidence of seizures is expected 36 hours following the onset of alcohol withdrawal.

Pathophysiology:
Chronic alcohol consumption enhances GABA mediated inhibition in the CNS (similar to benzodiazepines) and inhibits NMDA-type glutamate receptors. Alcohol withdrawal is thought to lead to the opposite (decreased inhibitory GABA and increased NMDA glutamate transmission).

Clinical course in alcohol withdrawal:
Symptoms begin 6-12 hours following the onset of alcohol withdrawal
Seizures occur 36 hours following the onset of withdrawal
Delirium tremens (coarse tremor, confusion, delusions, auditory and visual hallucinations, fever, tachycardia) occurs approximately 72 hours after the onset of alcohol withdrawal.

Management
First-line: benzodiazepines e.g. lorazepam, chlordiazepoxide.
Carbamazepine is also effective in the treatment of alcohol withdrawal.
Phenytoin is said not to be as effective in the treatment of alcohol withdrawal seizures.

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.

The most probable diagnosis in this patient is De Clerambault’s syndrome, also known as erotomania, which is a form of paranoid delusion with an amorous quality. The patient, often a single woman, believes that a famous person is in love with her.

Other options:
– Bouffée délirante is an acute psychotic disorder in which hallucinations, delusions or perceptual disturbances are obvious but markedly variable, changing from day to day or even from hour to hour.
– Fregoli delusion is the mistaken belief that some people currently present in the deluded person’s environment (typically a stranger) is a familiar person in disguise.
– Capgras delusion is the belief that significant others have been replaced by impostors, robots or aliens.
– Couvade is the common but poorly understood phenomenon whereby the expectant father experiences somatic symptoms during the pregnancy for which there is no recognized physiological basis.

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.

The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. 
Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.
Treatment:
– The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam.
– If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.
– Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.
– It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.

Sildenafil administration to patients who are using organic nitrates, either regularly and/or intermittently, in any form is contraindicated.
Organic nitrates and nitric oxide (NO) donors exert their therapeutic effects on blood pressure and vascular smooth muscle by the same mechanism as endogenous NO via increasing cGMP concentrations.