Mechanism of action of low molecular weight heparin (LMWH):
It inhibits coagulation by activating antithrombin III. Antithrombin III binds to and inhibits factor Xa. In doing so it prevents activation of the final common path; Xa inactivation means that prothrombin is not activated to thrombin, thereby not converting fibrinogen into fibrin for the formation of a clot.

LMHW is a small fragment of a larger mucopolysaccharide, heparin. Heparin works similarly, by binding antithrombin III and activating it. Heparin also has a binding site for thrombin, so thrombin can interact with antithrombin III and heparin, thus inhibiting coagulation.
Heparin has a faster onset of anticoagulant action as it will inhibit not only Xa but also thrombin, while LMWH acts only on Xa inhibition.

Compared to heparin, LMWHs have a longer half-life, so dosing is more predictable and can be less frequent, most commonly once per day.

Dosage and uses:
LMWH is administered via subcutaneous injection. This has long-term implications on the choice of anticoagulant for prophylaxis, for example, in orthopaedic patients recovering from joint replacement surgery, or in the treatment of DVT/PE.

Adverse effects:
The main risk of LMWH will be bleeding. The specific antidote for heparin-induced bleeding is protamine sulphate.
Less commonly it can cause:
Heparin-induced thrombocytopenia (HIT)
Osteoporosis and spontaneous fractures
Hypoaldosteronism
Hypersensitivity reactions

Finasteride inhibits the formation of dihydrotestosterone.
Finasteride is a 5α-reductase inhibitor and thus, inhibits the conversion of testosterone to dihydrotestosterone (DHT).

DHT is much more active than testosterone and binds more avidly to cytoplasmic receptors. DHT stimulates prostate growth and may be responsible for benign prostatic hyperplasia in the elderly.

Thus, finasteride can cause a reduction in prostatic volume and help in managing a patient with benign prostatic hyperplasia.

In a patient with abnormal LFTs and UC, think primary sclerosing cholangitis (PSC). MRCP and liver biopsy is the best answer. MRCP will show classically beads on a string – intra and extrahepatic stricturing and dilation. Remember this finding!! Liver biopsy is required for official diagnosis (need tissue!).

People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.
In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.

The wedged hepatic venous pressure is a reflection of the portal venous pressure in the hepatic sinusoids. This is a fact to remember. Here is a great but concise explanation as to why: https://www.ncbi.nlm.nih.gov/pubmed/18695309

Generalized Anxiety Disorder (GAD) is characterized by persistent and excessive worry about a number of different things. People with GAD may anticipate disaster and may be overly concerned about money, health, family, work, or other issues. Individuals with GAD find it difficult to control their worry. They may worry more than seems warranted about actual events or may expect the worst even when there is no apparent reason for concern.

GAD is diagnosed when a person finds it difficult to control worry on more days than not for at least six months and has three or more symptoms.

Treatment usually consists of a combination of pharmacotherapy and/or psychotherapy. Antidepressant agents are the drugs of choice in the treatment of anxiety disorders, particularly the newer agents, which have a safer adverse effect profile and higher ease of use than the older tricyclic antidepressants (TCAs), such as selective serotonin reuptake inhibitors (SSRIs).

Erythromycin is a bacteriostatic antibiotic. This means it stops the further growth of bacteria rather than directly destroying it. This is achieved by inhibiting protein synthesis. Erythromycin binds to the 23S ribosomal RNA molecule in the 50S subunit of the bacterial ribosome. This causes a blockage in the exiting of the peptide chain that is growing. Given that humans have 40S and 60S subunits, and do not have 50S subunits, erythromycin does not affect protein synthesis in human tissues.

The best treatment for the patient in question would be methylene blue.
The most probable diagnosis in this patient is methemoglobinemia due to the ingestion of amyl nitrate.

Amyl nitrate promotes the formation of methaemoglobin, which avidly conserves oxygen and leads to decreased tissue oxygen saturations.

Treatment of choice includes methylene blue and vitamin C.

Adverse effects:
Benign side effects include green or blue discoloration of urine and patients should be forewarned.
Significant side effects are based on methylene blue, itself, being an oxidizing agent and an inhibitor of monoamine oxidase A (MAO-A).
As an oxidizing agent, methylene blue can actually precipitate methemoglobinemia or haemolysis in high doses or when ineffectively reduced.
Methylene blue administration in a patient taking a serotonergic agents may predispose to serotonin syndrome.

Note: Although methylene blue administration is controversial in the setting of G6PD-deficiency due to reduced levels of NADPH, it is not contraindicated and should be administered cautiously and judiciously.

A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).
An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.

Arterial ischemia ulcers present with many of the symptoms observed in this patient: ulcer on the lower extremities, pain, swelling, yellow sores, a punched-out appearance, the foot turning red when dangling from a bed. Smoking a lot is also known to be a causative factor here. This type of ulcer develops due to damage to the arteries caused by a lack of blood flow to the tissue – they are also deep wounds. Venous ischemic ulcers usually form in the knee or inner ankle area as opposed to the foot.

The most appropriate steps of initial management include iv glucagon and iv isoprenaline.

The most likely diagnosis in the above scenario (decreased conscious level, profound hypertension, and bradycardia) is β-blocker toxicity/overdose.
Bronchospasm rarely occurs in an overdose of β-blockers, except where there is a history of asthma.

Immediate management is to give iv glucagons (50–150μg/kg) followed by infusion to treat hypotension and isoprenaline or atropine to treat bradycardia.
Where patients fail to respond to these measures, temporary pacing may be required.
If the patient is seen within the first 4 hours of the overdose, gastric lavage may be of value.

The patient is most likely to have Medullary Thyroid Carcinoma (MTC).
Sporadic, or isolated MTC accounts for 75% of cases and inherited MTC constitutes the rest.
Inherited MTC occurs in association with multiple endocrine neoplasia (MEN) type 2A and 2B syndromes, but non-MEN familial MTC also occurs.
A 24-hour urinalysis for catecholamine metabolites (e.g., vanillylmandelic acid [VMA], metanephrine) has to be done to rule out concomitant pheochromocytoma in patients with MEN type 2A or 2B, as Pheochromocytoma must be treated before MTC.

J waves in an ECG is associated with hypothermia, hypercalcemia, the Brugada syndrome, and idiopathic ventricular fibrillation. The other responses are all associated with atrial myxoma

Lofgren’s syndrome is an acute form of sarcoidosis characterized by erythema nodosum, bilateral hilar lymphadenopathy (BHL), and polyarthralgia or polyarthritis. Other symptoms include anterior uveitis, fever, ankle periarthritis, and pulmonary involvement.

Löfgren syndrome is usually an acute disease with an excellent prognosis, typically resolving spontaneously from 6-8 weeks to up to 2 years after onset. Pulmonologists, ophthalmologists, and rheumatologists often define this syndrome differently, describing varying combinations of arthritis, arthralgia, uveitis, erythema nodosum, hilar adenopathy, and/or other clinical findings.

The patient likely has celiac’s disease, but if she has been avoiding gluten, a biopsy may be negative. Even though a biopsy is the gold standard for diagnosis, she will need to re-introduce gluten into her diet prior to undergoing the biopsy.

Initiation of allopurinol treatment during an attack can exacerbate and prolong the episode. Thus treatment should be delayed until the attack resolves.

Sickle cell anaemia is characterised by periods of good health with intervening crises. One of the main types is aplastic crisis characterised by a sudden fall in haemoglobin without marked reticulocytosis (3%—in this case—is just above the normal range). It usually occurs secondary to parvovirus infection.

The other main types of sickle cell crises are thrombotic crisis (painful or vaso-occlusive crisis), sequestration crisis, and haemolytic crisis. Thrombotic crisis is precipitated by infection, dehydration, alcohol, change in temperature, and deoxygenation. Sequestration crisis is characterised by acute chest syndrome (i.e. fever, dyspnoea, chest/rib pain, low pO2, and pulmonary infiltrates). In haemolytic crisis, fall in haemoglobin occurs secondary to haemolysis. It is a rare type of sickle cell crises.

Intracranial pressure (ICP) is a complex brain modality that determines cerebral perfusion pressure (CPP), which is the difference between arterial blood pressure (ABP), and ICP. Raised ICP reduces CPP and blood delivery to the brain. This jeopardizes cerebral function and organismal survival in many species. A massive rise in ICP is also known to produce an increase in ABP, bradycardia and respiratory irregularities termed Cushing response. This mechanism is generally considered to be an agonal and terminal event occurring in extreme condition of brainstem ischaemia leading to a sympatho-adrenal response.

Rheumatoid arthritis is a polyarthritis that results in symmetrical pain and swelling of the affected joints (also at rest). It particularly affects the metacarpophalangeal joints (MCPJs) and proximal interphalangeal joints (PIPJs), not the distal interphalangeal joints (DIPs).
Ulcerative colitis and IBD are associated with seronegative arthritides, not RA. The condition can also cause various extra-articular manifestations such as ocular symptoms, rheumatoid nodules and pulmonary fibrosis. Scleritis, episcleritis and keratoconjunctivitis sicca are more common than uveitis. Early intervention with disease-modifying antirheumatic drugs (DMARDs) plays a decisive role in successful treatment.

The main cause of growth hormone (GH) deficiency is a pituitary tumour or the consequences of treatment of the tumour including surgery and/or radiation therapy.
Sheehan’s syndrome (SS) is postpartum hypopituitarism caused by necrosis of the pituitary gland. It is usually the result of severe hypotension or shock caused by massive haemorrhage during or after delivery. Patients with SS have varying degrees of anterior pituitary hormone deficiency.

Laron syndrome is Insulin-like growth factor I (IGF-I) deficiency due to GH resistance or insensitivity due to genetic disorders of the GH receptor causing GH receptor deficiency.