Tuberculous lymphadenitis is a chronic, specific granulomatous inflammation of the lymph node with caseation necrosis, caused by infection with Mycobacterium tuberculosis or a related bacteria. The characteristic morphological element is the tuberculous granuloma (caseating tubercle).

The incidence rate is the number of new cases per population at risk in a given time period. For example, if a population initially contains 1,000 non-diseased persons and 28 develop a condition over two years of observation, the incidence proportion is 28 cases per 1,000 persons per two years, i.e. 2.8% per two years.
Prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seat-belt use). It is derived by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage, or as the number of cases per 10,000 or 100,000 people.
Incidence should not be confused with prevalence, which is the proportion of cases in the population at a given time rather than rate of occurrence of new cases. Thus, incidence conveys information about the risk of contracting the disease, whereas prevalence indicates how widespread the disease is.

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.

This scenario is suggestive of a pancreatic head mass with obstructive jaundice and US showing a ‘double duct’ sign. A CT Scan would be recommended to evaluate for a pancreatic head mass. If a mass was found, the next step would then be to do an ERCP with EUS to obtain a biopsy of the mass for tissue diagnosis. Laparoscopy would not be recommended. CA19-9 would not be diagnostic.

A very common complication after ERCP is post-ERCP pancreatitis, which based on the clinical scenario , this man has. The treatment for this is pain control, lots of intravenous fluids, and traditionally bowel rest, although more recent evidence suggests early feeding is better.

Asthma is a condition characterized by airway hyperresponsiveness, which results in reversible increases in bronchial smooth muscle tone, and variable amounts of inflammation of the bronchial mucosa.
During an acute asthma attack, the already inflamed airways narrow further due to bronchospasm, which leads to increased airway resistance. Because of the increased smooth muscle tone during an asthma attack, the airways also tend to close at abnormally high lung volumes, trapping air behind occluded or narrowed small airways. Thus the acute asthmatic will breathe at high lung volumes, his functional residual capacity will be elevated, and he will inspire close to total lung capacity. The accessory muscles of respiration are often used to maintain the lungs in a hyperinflated state.

During episodes of acute asthma, pulmonary function tests reveal an obstructive pattern. This includes a decrease in the rate of maximal expiratory air flow (a decrease in FEV1 and the FEV1/FVC ratio) due to the increased resistance, and a reduction in forced vital capacity (FVC) correlating with the level of hyperinflation of the lungs. Because these patients breathe at such high lung volumes (near the top of the pressure-volume curve, where lung compliance greatly decreases), they must exert significant effort to create an extremely negative pleural pressure, and consequently fatigue easily. Overinflation also reduces the curvature of the diaphragm, making it less efficient in generating further negative pleural pressure.

Liver cirrhosis is not associated with hyposplenism.

Hyposplenism is caused by a variety of conditions. These are:
1. Splenectomy
2. Sickle cell anaemia
3. Coeliac disease, dermatitis herpetiformis
4. Graves’ disease
5. Systemic lupus erythematosus (SLE)

History of recurrent infections and failure to thrive (probably due to pancreatic enzyme insufficiency) is highly suggestive of cystic fibrosis. Pseudomonas has been identified as an important respiratory pathogen in patients with cystic fibrosis.

Throughout pregnancy the tubular reabsorption of glucose is less effective than in the non-pregnant state, this leads to glycosuria.

Insulinoma is associated with LOW fasting glucose, HIGH insulin level, and HIGH C peptide. Insulin-abuse or overdose will cause HGH insulin levels and a LOW C peptide. If the C peptide is low, be suspicious.

The most probable diagnosis in this patient is post-traumatic stress disorder (PTSD). The first-line treatment for this patient would be cognitive behavioural therapy or eye movement desensitization and reprocessing therapy.

Post-traumatic stress disorder (PTSD) can develop in people of any age following a traumatic event, for example, a major disaster or childhood sexual abuse. It encompasses what became known as ‘shell shock’ following the first world war. One of the DSM-IV diagnostic criteria is that symptoms have been present for more than one month.

Clinical features:
Re-experiencing: flashbacks, nightmares, repetitive and distressing intrusive images
Avoidance: avoiding people, situations or circumstances resembling or associated with the event
Hyperarousal: hypervigilance for threat, exaggerated startle response, sleep problems, irritability and difficulty concentrating
Emotional numbing – lack of ability to experience feelings, feeling detached from other people
Depression
Drug or alcohol misuse
Anger

Management:
Following a traumatic event single-session interventions (often referred to as debriefing) are not recommended
Watchful waiting may be used for mild symptoms lasting less than 4 weeks
Trauma-focused cognitive-behavioural therapy (CBT) or eye movement desensitization and reprocessing (EMDR) therapy may be used in more severe cases
Drug treatments for PTSD should not be used as a routine first-line treatment for adults.
If drug treatment is used then paroxetine or mirtazapine are recommended.

Causes for right axis deviation:
-Right ventricular hypertrophy and Left posterior fascicular block
-Lateral myocardial infarction.
-Acute or chronic lung diseases: Pulmonary embolism, pulmonary hypertension, chronic obstructive pulmonary disease (COPD), cor pulmonale.
-Congenital heart disease (e.g., dextrocardia, secundum atrial septal defect).
-Wolff-Parkinson-White syndrome.
-Ventricular ectopic rhythms (e.g., ventricular tachycardia).

Given that the patient has had large amount, high volume watery diarrhoea in an acute period of time, from the answer choices given, this narrows the diagnosis down to VIPoma or carcinoid syndrome. You would expect with carcinoid syndrome for there to be periodic episodes of diarrhoea, though, with a description of flushing, additionally, associated with these episodes. Thus, VIPoma is the most likely answer here. VIPomas are known to cause hypokalaemia from this large amount of watery diarrhoea. Stool volume should be > 700 ml/day.

In the petrous temporal bone the facial nerve produces three branches:
1. The greater petrosal nerve, which transmits preganglionic parasympathetic fibres to the sphenopalatine ganglion. These postganglionic fibres supply the lacrimal gland and the glands in the nasal cavity;
2. The nerve to stapedius;
3. Parasympathetic fibres to the submandibular and sublingual glands and taste fibres from the anterior two-thirds of the tongue.

Sitagliptin-induced pancreatitis can occur at any time after the initiation of therapy, even after several years. Patients taking sitagliptin who present with signs and symptoms of mild or severe pancreatitis should immediately discontinue sitagliptin and use an alternate medication regimen for control of type 2 diabetes.
In response to pancreatitis reported in post-marketing surveillance through the Adverse Event Reporting System (AERS), the FDA has issued revised prescribing information for sitagliptin stating that cases of acute pancreatitis have been reported with use, to monitor closely for signs and symptoms of pancreatitis, and to use sitagliptin with caution in patients with a history of pancreatitis.

To differentiate ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrant conduction the following electrocardiographic features should be looked for:

Evidence of preceding atrial activity for SVT. Oesophageal leads are helpful if P waves are hidden in the QRS complex.
QRS duration more than 140 ms for VT.
QRS morphology: Features of QRS morphology that favour SVT are RBBB or triphasic patterns like rSR in V1 and qRS in V6. Monophasic pattern like R or qR in V1 and rS or QS in V6 or multiple morphology QRS complexes favour VT.
AV dissociation for VT.

Pre-eclampsia is excluded from negative proteinuria. White coat hypertension is excluded with ambulatory blood pressure monitoring. Pregnancy induced hypertension develops after 20 weeks of gestation. So the most likely answer is pre-existing hypertension. She should be investigated for a secondary cause for hypertension.

The somatostatin-secreting D-cells comprise ,5% of the cells of the pancreatic islets. The D-cells have a complex morphology and may, via cellular process, interact with many more islet cells than suggested by their low number. D-cells are equipped with ATP-sensitive potassium channels (KATP channels).

Current guidelines recommend the use of ambrisentan, Bosentan (recommendation I, level of evidence A) and macitentan (I, B) in patients with PAH and WHO functional class II and III. In WHO functional class IV, the first-line drug is Epoprostenol and the recommendation for Endothelin receptor antagonists is weaker (IIb, C).

The rash is a characteristic sign of meningitis. Added to photophobia, headache and neck rigidity, meningitis is highly suggested diagnosis. IV antibiotics should be started immediately.

Acute angle closure glaucoma is associated with hypermetropia, whereas primary open-angle glaucoma is associated with myopia. Glaucoma is a group of eye disorders characterised by optic neuropathy due, in the majority of patients, to raised intraocular pressure (IOP). It is now recognised that a minority of patients with raised IOP do not have glaucoma and vice versa.

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.

The clinical picture is characteristic of retinal detachment, which should be treated immediately to prevent permanent loss of vision. Scleral buckling is a surgical procedure used to repair a retinal detachment, where the surgeon attaches a piece of silicone or a sponge onto the white of the eye at the spot of a retinal tear pushing the sclera toward the retinal tear or break, promoting repair. Signs of detachment include an increase in the number of eye floaters, flashes of light in the field of vision, and reduced peripheral vision.

Most new moms experience postpartum baby blues after childbirth, which commonly include mood swings, crying spells, anxiety and difficulty sleeping. Baby blues typically begin within the first two to three days after delivery, and may last for up to two weeks.

Postpartum depression may be mistaken for baby blues at first — but the signs and symptoms are more intense and last longer, and may eventually interfere with your ability to care for your baby and handle other daily tasks. Symptoms usually develop within the first few weeks after giving birth, but may begin earlier, during pregnancy or later, up to a year after birth.

The period prevalence of postpartum depression among women is a striking 21.9% the first year after birth, which makes it one of the most common medical complications of childbearing. Sertraline has been identified as an antidepressant of choice for breastfeeding women because infants are unlikely to develop quantifiable serum sertraline levels and very few adverse events associated with sertraline have been reported.

Women with a prior episode of postpartum psychosis have about a 30% risk of having another episode in the next pregnancy.

This patient’s symptoms of anaemia, leukopenia, and elevated non-albumin protein concentration with fatigue and weight loss, point to myeloma. Thus plasma protein electrophoresis or Serum Protein Electrophoresis (SPE) is indicated when there is suspicion of myeloma.

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.

In the PCR, DNA amplification is performed by thermostable enzymes; invariably either family A DNA polymerases from thermophilic and hyperthermophilic Bacteria or family B DNA polymerases from hyperthermophilic Archaea. Family Y DNA polymerase from the hyperthermophilic archaeon Sulfolobus solfataricus, Sso-polY, is also an enzyme marketed for PCR, but with specialist applications. Each thermostable DNA polymerases has different characteristics and to achieve optimal results, the choice of a PCR enzyme depends on the application itself.

An MRI whole spine should be performed in a patient suspected of spinal metastasis which can occur before developing metastatic spinal cord compression. This patient has renal cell carcinoma, which readily metastasises to the bones and also has progressive back pain. He, therefore, needs urgent imaging of his spine before any neurological compromise develops. MRI whole spine is preferable because patients with spinal metastasis often have metastases at multiple levels within the spine. Plain radiographs and CT scans should not be performed as they have a lower sensitivity for revealing lesions and cannot exclude cord compression.

In general, imaging should be performed within one week if symptoms suspicious of spinal metastasis without neurological symptoms are present. If there are symptoms suggestive of malignant spinal cord compression, then imaging should be done within 24 hours.

The signs and symptoms of spinal metastases include:
1. Unrelenting lumbar back pain
2. Thoracic or cervical back pain
3. Pain associated with tenderness and worsens with sneezing, coughing, or straining
4. Nocturnal pain

Neuropathic pain may be defined as pain which arises following damage or disruption of the nervous system. It is often difficult to treat and responds poorly to standard analgesia.
The most recent update to the NICE guidelines for management of neuropathic pain occurred in 2013: first-line treatment* includes amitriptyline. If the first-line drug treatment does not work then move on to one of the other 3 drugs: duloxetine, gabapentin or pregabalin. Tramadol may be used as ‘rescue therapy’ for exacerbations of neuropathic pain. Topical capsaicin may be used for localised neuropathic pain (e.g. post-herpetic neuralgia). Pain management clinics may be useful in patients with resistant problems.

*please note that for some specific conditions the guidance may vary. For example carbamazepine is used first-line for trigeminal neuralgia.

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8;14).

Burkitt lymphoma is a rare high-grade non-Hodgkin lymphoma endemic to west Africa and the mosquito belt. It has a close association with the contraction of Epstein-Barr virus (EBV). Burkitt lymphoma often presents with symmetrical painless lymphadenopathy, systemic B symptoms (fever, sweats, and weight loss), central nervous system involvement, and bone marrow infiltration. Classically in the textbooks, the patient also develops a large jaw tumour.

Other aforementioned options are ruled out because:
1. t(9;22)—Chronic myeloid leukaemia
2. t(15;17)—Acute promyelocytic leukaemia
3. t(14;18)—Follicular Lymphoma
4. t(11;14)—Mantle Cell Lymphoma