In patients with acute renal tubular necrosis, infection in the form of gram-negative septicaemia is the most common cause of death, especially while the patient is awaiting spontaneous recovery of their renal function.

The best answer is cytomegalovirus. The mother was infected during the pregnancy and the baby has developed cytomegalo-inclusion syndrome. Histologically, it is identified by viral particles surrounded by lysosomes.

Salbutamol stimulates beta-2 adrenergic receptors, which are the predominant receptors in bronchial smooth muscle (beta-2 receptors are also present in the heart in a concentration between 10% and 50%).

Stimulation of beta-2 receptors leads to the activation of enzyme adenyl cyclase that forms cyclic AMP (adenosine-mono-phosphate) from ATP (adenosine-tri-phosphate). This increase of cyclic AMP relaxes bronchial smooth muscle and decrease airway resistance by lowering intracellular ionic calcium concentrations. Salbutamol relaxes the smooth muscles of airways, from trachea to terminal bronchioles.

Increased cyclic AMP concentrations also inhibits the release of bronchoconstrictor mediators such as histamine and leukotriene from the mast cells in the airway.

Computed tomographic pulmonary angiography (CTPA) is the standard investigative tool, used for diagnosing a pulmonary embolism. Pulmonary angiography is indicated if CTPA is not available.

The prognosis of breast cancer depends chiefly on the extent of nodal metastases.

The breast cancer TNM staging system is the most common way that doctors use to stage breast cancer. TNM stands for Tumour, Node, Metastasis. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero), which is non-invasive ductal carcinoma in situ (DCIS), and stages I through IV (1 through 4), which are used for invasive breast cancer.

Staging can be clinical or pathological. Clinical staging is based on the results of tests done before surgery, which may include physical examinations, mammogram, ultrasound, and MRI scans. Pathologic staging is based on what is found during surgery to remove breast tissue and lymph nodes. In general, pathological staging provides the most information to determine a patient’s prognosis.

The branches of the common peroneal nerve innervate the skin of the dorsum of the foot as well as the muscles which help to carry out dorsiflexion of the foot. Compression of the common peroneal nerve cause foot drop as well as the loss in sensation of the skin on the dorsum of the foot.

The most probable diagnosis is perforated peptic ulcer. History of possible NSAID/steroid use for joint pain, sudden-onset severe epigastric pain, vomiting and shoulder tip pain, support the diagnosis. Erect CXR will show the air under the diaphragm which is diagnostic.

Lewy body dementia is the second most common cause of dementia in the elderly after Alzheimer’s disease. The core feature is a progressive dementia, but other characteristic features include Parkinsonism, visual hallucinations, fluctuating cognitive abilities and executive function, and an increased risk of falls or autonomic failure.

Prevention of osteoporosis associated with chronic glucocorticoid therapy is done by administrating bisphosphonates. Oral bisphosphonates are indicated for patients aged above 65 who have been on steroid therapy for over 3 months, so as to reduce the risk of steroid induced osteoporosis. HRT is usually done in post menopausal women who have oestrogen related bone resorption.

(Diabetic) Amyotrophy is a condition that presents with muscle wasting and consequent difficulty in climbing stairs. The onset is relatively sudden and symptoms of diabetes are characteristic.

The patient is most likely to have Postpartum thyroiditis which goes through 2 phases; hypothyroid and a hyperthyroid phase.
The hyperthyroid phase of postpartum thyroiditis occurs between 2 and 10 months postpartum. Most commonly, it presents at 3 months. Symptoms more common in women with hyperthyroid postpartum thyroiditis include palpitations, fatigue, heat intolerance, and irritability/nervousness. The frequency of asymptomatic hyperthyroidism is 33%.
Untreated, the hyperthyroidism resolves spontaneously within 2-3 months. This phase is diagnosed by the combination of a low serum TSH concentration in the presence of thyroid peroxidase antibodies, in women who are TSH receptor antibody-negative. Free T4 levels are typically elevated but may be normal.
Treatment of hyperthyroidism, when necessary, is based on symptom severity and should be a joint decision of patient and physician. Beta-blockers such as propranolol are given to alleviate palpitations, irritability, and nervousness. The morbidity associated with treatment is the side effects of beta-blockade. The downside of withholding treatment is allowing the woman to remain symptomatic. Antithyroid medicines (thioureas) are not a potential treatment alternative, because the hyperthyroidism is caused by destructive thyroiditis resulting in the release of preformed thyroid hormone.

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 patient’s age and symptoms suggest Grave’s disease with thyroid-associated ophthalmopathy. In Grave’s disease, weight loss is noticed regardless of normal eating habits of the patient. Palpitations are also typical and may be confused with a panic attack. Proptosis is usually bilateral, but unilateral is also possible.

Androgen insensitivity syndrome (AIS), previously referred to as testicular feminization, is an X-linked disorder in which the patients are genotypically male (possessing and X and Y chromosome) and phenotypically female. This disorder is rare, with reported incidences from 1 in 20,000 to 1 in 60,000 live male births, and is the result of a missing gene on the X chromosome that is responsible for the cytoplasmic or nuclear testosterone receptor. In its absence, the gonad, which is a testis, produces normal amounts of testosterone; however, the end tissues are unable to respond due to the deficient receptors leading to the external genitalia developing in a female fashion. Anti-mullerian hormone, which is produced by the testis, is normal in these patients, leading to regression of the Mullerian duct. Wolffian duct development, which depends on testosterone, does not occur as the ducts lack the receptors.
The cumulative effect is a genotypic male with normal external female genitalia (without pubic or axillary hair), no menses, normal breast development, short or absent vagina, no internal sex organs, and the presence of testis. Frequently, these patients have bilateral inguinal hernias in childhood, and their presence should arouse suspicion of the diagnosis.

Tumour lysis syndrome (TLS), triggered by the introduction of chemotherapy, has resulted in the aforementioned symptoms in this patient.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Rasburicase should be given prior to chemotherapy in order to reduce the risk of tumour lysis syndrome (TLS). Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin. Allantoin is 5-10 times more soluble than uric acid, hence, renal excretion is more effective.

Burkitt lymphoma is a high-grade B-cell neoplasm. There are two major forms:
1. Endemic (African) form: typically involves maxilla or mandible.
2. Sporadic form: abdominal (e.g. ileocaecal) tumours are the most common form. More common in patients with HIV.

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8;14). The Epstein-Barr virus (EBV) is strongly implicated in development of the African form of Burkitt lymphoma and to a lesser extent, the sporadic form.

Management of the lymphoma is with chemotherapy. This tends to produce a rapid response which may cause TLS.

Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with severe chronic obstructive pulmonary disease (COPD) associated with resting hypoxaemia. When appropriately prescribed and correctly used, LTOT has clearly been shown to improve survival in hypoxemic COPD patients. Requirements to proceed to LTOT is the patient should be stable and on appropriate optimum therapy (as in given case) and having stopped smoking tobacco. The patient should be shown to have a PaO2 of less than 7.3 kPa and/or a PaCO2 of greater than 6 kPa on two occasions at least 3 weeks apart. FEV1 should be less than 1.5 litres, and there should be a less than 15% improvement in FEV1 after bronchodilators. Patients with a PaO2 between 7.3 and 8 kPa who have polycythaemia, right heart failure or pulmonary hypertension may benefit from LTOT.

The best option would be the combination of ampicillin and gentamycin. Changing to IV amoxicillin+gentamycin is however the best among the given choices here.

Neutrophilia is also commonly associated with polycythaemia vera.

Polycythaemia vera (PV), also known as polycythaemia rubra vera, is a myeloproliferative disorder caused by clonal proliferation of marrow stem cells leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets. It has peak incidence in the sixth decade of life, with typical features including hyperviscosity, pruritus, splenomegaly, haemorrhage (secondary to abnormal platelet function), and plethoric appearance.

Some management options of PV include lose-dose aspirin, venesection (first-line treatment), hydroxyurea (slightly increased risk of secondary leukaemia), and radioactive phosphorus (P-32) therapy.

In PV, thrombotic events are a significant cause of morbidity and mortality. 5-15% of the cases progress to myelofibrosis or AML. The risk of having AML is increased with chemotherapy treatment.

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).

As the patient is turning blue, giving oxygen will be the first priority in his management.

Hyoscine should be used to help dry the secretions – this is because it acts as an antimuscarinic agent. It also causes less sedation than hyoscine hydrobromide, however, both are administered through injection or infusion.

Spironolactone induces gynecomastia by blocking androgen production. It blocks androgens from binding to their receptors, and increasing both total and free oestrogen levels. Generally, discontinuation of treatment results in resolution of the gynecomastia. Other drugs which cause gynecomastia are calcium channel blockers (Nifedipine, Amlodipine, Verapamil, Diltiazem), ACE inhibitors (Captopril, Enalapril), alpha receptor blockers (Doxazocin, Prazosin) and centrally acting agents (Clonidine, Methyldopa, Reserpine).

European guidelines for the treatment of syndrome of inappropriate antidiuresis include the following recommendations for the management of moderate or profound hyponatremia:
– Restrict fluid intake as first-line treatment.
– Second-line treatments include increasing solute intake with 0.25-0.50 g/kg per day or a combination of low-dose loop diuretics and oral sodium chloride.
– Use of lithium, demeclocycline, or vasopressin receptor antagonists is not recommended.
Recommendations on the treatment of SIADH from an American Expert Panel included the following:
– If chronic, limit the rate of correction.
– Fluid restriction should generally be first-line therapy.
– Consider pharmacologic therapies if serum Na + is not corrected after 24-48 hr of fluid restriction or if the patient has a low urinary electrolyte free water excretion.
– Patients being treated with vaptans should not be on a fluid restriction initially.
– Water, 5% dextrose or desmopressin can be used to slow the rate of correction if the water diuresis is profound.

This patient meets the diagnostic criteria for neutropenic sepsis, which is a relatively common complication of cancer therapy – usually chemotherapy occurring 7-14 days after. It is defined as a neutrophil count of <0.5 x 10^9/L in a patient undergoing anticancer treatment and who has either a temperature higher than 38°C or has other features consistent with clinically significant sepsis. Management approach is the same as mentioned in this case. However, if the patient still remains unwell, then an antifungal such as amphotericin B is started after risk-stratifying the patient and carrying out investigations (e.g. HRCT and Aspergillus PCR) to determine the likelihood of systemic fungal infection.

Troponin testing is the most important investigation in risk stratification. Troponin positive patients should be referred for urgent coronary revascularization as troponin indicates cardiac cell damage.

Out of the aforementioned markers, low corrected calcium is the only biochemistry result consistent with the diagnosis. All of the other markers are elevated in TLS.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. As phosphate precipitates calcium, the serum concentration of calcium becomes low. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups
should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

Digoxin is a cardiac glycoside, having positive inotropic effects on the heart. It increases the strength of contractility of the heart, increasing the heart rate, but lowering blood pressure. This patient developed weakness in his limbs most likely caused by extremely low blood pressure that could be due to diseased blood vessels reacting to the side-effects of digoxin, therefore an angiography would be the best investigation.