Cephalosporins, such as ceftriaxone, do not cover methicillin-resistant staph aureus. They do cover some gram positives and gram negatives. Vancomycin and teicoplanin given intravenously have good coverage of MRSA and other gram positive bacteria. Rifampicin and doxycycline, although not the best treatment, can be used for outpatients if there are no systemic signs of illness.

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.

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.

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.

Mycoplasma infection causes cold autoimmune haemolytic anaemia (AIHA). The rest of the aforementioned options cause warm AIHA.

AIHA may be divided into ‘warm’ and ‘cold’ types, according to the temperature at which the antibodies best cause haemolysis. It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection, or drugs.

1. Warm AIHA:
In warm AIHA, the antibody (usually IgG) causes haemolysis best at body temperature and tends to occur in extravascular sites, for example, spleen. Management options include steroids, immunosuppression, and splenectomy. It is caused by autoimmune diseases such as SLE (rarely causes mixed-type AIHA), cancers such as lymphomas and CLL, and drugs such as methyldopa.

2. Cold AIHA:
The antibody in cold AIHA is usually IgM and causes haemolysis best at 4°C and occurs more commonly intravascularly. Features may include symptoms of Raynaud’s disease and acrocyanosis. Patients do not respond well to steroids. Cold AIHA is caused by cancers such as lymphomas, and infections such as mycoplasma and EBV.

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.

Furosemide is a loop diuretic that is known to have significant ototoxicity side-effects although the mechanism is not fully known.

The diagnosis is acute inferior ST elevation myocardial infarction so the most appropriate management is primary angioplasty.

Most patients with psoriatic arthritis present with monoarthritis or asymmetric oligoarthritis. The most common form of the disease is the one involving a few joints of the peripheral skeleton with a distinct asymmetry of symptoms. Involvement of the smaller joints of the hands and feet, especially distal interphalangeal joints, seems to be a characteristic feature. Arthritis mutilans is a rare and severe complication of psoriatic arthritis.

In myasthenia gravis, repeated muscle contractions lead to reduced muscle strength. The opposite is however classically seen in the related disorder Lambert-Eaton syndrome. Lambert-Eaton myasthenic syndrome is seen in association with small cell lung cancer, and to a lesser extent breast and ovarian cancer. It may also occur independently as an autoimmune disorder. Lambert-Eaton myasthenic syndrome is caused by an antibody directed against pre-synaptic voltage gated calcium channel in the peripheral nervous system.

MRA is next appropriate management for this case. It is non-invasive and has been shown to correlate with angiographic appearance. Although Renal arteriography is considered gold standard, it is invasive, so a non-invasive option is preferred as first line of investigation in this case.

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.

Arthrocentesis should usually be done when there is a suspicion of pseudogout or septic arthritis as in this case which leads to an early diagnosis and prompt treatment. Polarized microscopy demonstrates weakly positively birefringent rhomboid crystals which are blue when parallel to light and yellow when perpendicular to light. Elevated serum uric acid levels that cause gout are usually found after large consumption of alcohol or meat, or post surgery. Autoimmune diseases like SLE, RA etc require an autoimmune screen.

The presence of a third heart sound is the most sensitive indicator of heart failure. All of the other signs can be found in heart failure with varying degrees.

Glomerulosclerosis is the scarring and hardening of the glomeruli known as diabetic glomerulosclerosis occurring in long-standing diabetes.

Exposure to aniline dyes is a risk factor for transitional cell carcinoma. Aniline dyes are used in dyestuffs and pigment manufacturing.

The other aforementioned options are ruled out because:
1. Feed production may expose to aflatoxin (hepatocellular carcinoma).

2. Being a military personnel may expose to mustard gas (lung cancer).

3. Rubber industry may expose to nitrosamines (oesophageal and gastric cancer).

4. Refrigerant production before 1974 may expose to vinyl chloride (hepatic angiosarcoma).

The history is suggestive of hypertrophic obstructive cardiac myopathy. The degree of left ventricular hypertrophy is strongly associated with sudden cardiac death.

Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases, as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.

Use of Hyperbaric oxygen therapy (HBOT) for treatment of mild to moderate CO poisoning is not routine.
The selection criteria for HBOT in cases of CO poisoning include:
• COHb levels > 20-25%
• COHb levels > 20% in pregnant patient
• Loss of consciousness
• Severe metabolic acidosis (pH <7.1)
• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
Principle of HBOT:
Exposing patients to 100 percent oxygen under supra-atmospheric conditions results in a decrease in the half-life (t1/2) of COHb, from , 90 min in atmospheric air to , 30 minutes. The amount of oxygen dissolved in the blood also rises from , 0.3 to 6 mL/dL, increasing the delivery of non-haemoglobin-bound oxygen to the tissues.

Ocular manifestations of rheumatoid arthritis are common, with 25% of patients having eye problems. These manifestations include keratoconjunctivitis sicca (most common), episcleritis (erythema), scleritis (erythema and pain), corneal ulceration, and keratitis.

According to the latest research, beta blockers are associated with higher incidence of fatal and non-fatal strokes, all cardiovascular events, and cardiovascular mortality. New-onset diabetes also associates with beta blockers.

The positive family history and the smoking make him an ideal candidate for a myocardial infarction. The chest pain is also a suggestive symptom. So troponin is needed to rule out MI.

Bronchial carcinoids are uncommon, slow growing, low-grade, malignant neoplasms, comprising 1-2% of all primary lung cancers.
It is believed to be derived from surface of bronchial glandular epithelium. Mostly located centrally, they produce symptoms and signs of bronchial obstruction such as localized wheeze, non resolving recurrent pneumonitis, cough, chest pain, and fever. Haemoptysis is present in approximately 50% of the cases due to their central origin and hypervascularity.
Central bronchial carcinoids are more common than the peripheral type and are seen as endobronchial nodules or hilar/perihilar mass closely related to the adjacent bronchus. Chest X-ray may not show the central lesion depending on how small it is.

Othello syndrome (OS) is a type of paranoid delusional jealousy, characterized by the false absolute certainty of the infidelity of a partner, leading to preoccupation with a partner’s sexual unfaithfulness based on unfounded evidence. OS has been associated with psychiatric and neurological disorders including stroke, brain trauma, brain tumours, neurodegenerative disorders, encephalitis, multiple sclerosis, normal pressure hydrocephalus, endocrine disorders, and drugs.

The most possible diagnosis is a pituitary tumour. Pituitary tumours compress the optic chiasm inferiorly and can cause visual field defects (bitemporal hemianopia or quadrantanopia). Temporal arteritis usually develops in older people and acute glaucoma usually requires a family history. Amaurosis fugax is classed as a stroke and usually leads to reversible unilateral vision loss. A subconjunctival haemorrhage does not typically produce the symptoms described.

Osteoarthritis (OA) is a disabling joint disease characterized by a noninflammatory degeneration of the joint complex (articular cartilage, subchondral bone, and synovium) that occurs with old age or from overuse. It mainly affects the weight-bearing and high-use joints, such as the hip, knee, hands, and vertebrae. Despite the widespread view that OA is a condition caused exclusively by degenerative “wear and tear” of the joints, newer research indicates a significant heterogeneity of causation, including pre-existing peculiarities of joint anatomy, genetics, local inflammation, mechanical forces, and biochemical processes that are affected by proinflammatory mediators and proteases. Major risk factors include advanced age, obesity, previous injuries, and asymmetrically stressed joints. In early-stage osteoarthritis, patients may complain of reduced range of motion, joint-stiffness, and pain that is aggravated with heavy use. As the disease advances, nagging pain may also occur during the night or at rest. Diagnosis is predominantly based on clinical and radiological findings. Classic radiographic features of OA do not necessarily correlate with clinical symptoms and appearance. RA involves proximal interphalangeal joints not distal. Gout occurs as a result of overproduction or underexcretion of uric acid and frequently involves first toe. Fibromyalgia is a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues.

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.

Tumour marker CA 125 is mostly associated with primary peritoneal cancer and ovarian cancer. It can be used to monitor response to chemotherapy, alongside regular CT scans.

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)

DGI presents as two syndromes: 1) a bacteremic form that includes a triad of tenosynovitis, dermatitis, and polyarthralgias without purulent arthritis and 2) a septic arthritis form characterized as a purulent arthritis without associated skin lesions. Many patients will have overlapping features of both syndromes. Time from infection to clinical manifestations may range from 1 day to 3 months. There is no travel history and the rash of Lyme disease is not purulent. Reactive arthritis presents with conjunctivitis, urethritis and arthritis usually with a red hot tender and swollen joint.

Tumour lysis syndrome (TLS) occurs most notably in patients with haematological malignancies including, Non-Hodgkin’s Lymphoma (NHL) and Acute Lymphocytic Leukaemia (ALL).
Risk factors for TLS include:
• Large tumour burden
• Sensitivity of the tumour to chemotherapy
• Rapid tumour growth rate
TLS is characterized by:
• Hyperuricemia
• Hyperkalaemia
• Hyperphosphatemia
• Hypocalcaemia
Treatment of TLS:
• Allopurinol: It is a xanthine oxidase inhibitor, it reduces the conversion of nucleic acid by-products to uric acid. Thus, it prevents urate nephropathy and subsequent oliguric renal failure. Note: dose reduction is essential in renal failure or if given along with mercaptopurine or azathioprine.
Alternatives to Allopurinol: Febuxostat; Rasburicase are useful in patients with hyperuricemia.
• Hydration
• Diuresis: Should be considered in well hydrated patients with insufficient urine output. Furosemide to be considered in normo-volemic patients with hyperkalaemia. Urine alkalization can be considered for promoting alkaline diuresis.
• Treatment of electrolyte imbalances including hyperkalaemia, hyperphosphatemia, and hypocalcaemia.
• Dialysis can be considered in refractory cases.

Narcolepsy is a rare condition characterised by excessive daytime sleepiness, sleep paralysis, hypnagogic hallucinations, and cataplexy (sudden collapse triggered by emotion such as laughing or crying). There is no cure for narcolepsy. Treatment options include stimulants, such as methylphenidate (Ritalin) or modafinil (Provigil), antidepressants, such as fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft) and sodium oxybate (Xyrem). Modafinil has replaced methylphenidate and amphetamine as the first-line treatment of excessive daytime sleepiness (EDS).