Macular disease can affect central vision at any stage of diabetic retinopathy and may be seen in type 2 diabetic patients. Diabetic retinopathy affects up to 80 percent of those who have had diabetes for 20 years or more. Macular oedema occurs when damaged blood vessels leak fluid and lipids onto the macula, the part of the retina that lets us see detail. The fluid makes the macula swell, which blurs vision.

Extrinsic allergic alveolitis (EAA) refers to a group of lung diseases that can develop after exposure to certain substances. The name describes the origin and the nature of these diseases:

‘extrinsic’ – caused by something originating outside the body
‘allergic’ – an abnormally increased (hypersensitive) body reaction to a common substance
‘alveolitis’ – inflammation in the small air sacs of the lungs (alveoli)

Symptoms can include: fever, cough, worsening breathlessness and weight loss. The diagnosis of the disease is based on a history of symptoms after exposure to the allergen and a range of clinical tests which usually includes: X-rays or CT scans, lung function and blood tests.

EAA is not a ‘new’ occupational respiratory disease and occupational causes include bacteria, fungi, animal proteins, plants and chemicals.

Examples of EAA include:

Farmer’s lung
This is probably the most common occupational form of EAA and is the outcome of an allergic response to a group of microbes, which form mould on vegetable matter in storage. During the handling of mouldy straw, hay or grain, particularly in a confined space such as a poorly ventilated building, inhalation of spores and other antigenic material is very likely.

There also appears to be a clear relationship between water content of crops, heating (through mould production) and microbial growth, and this would apply to various crops and vegetable matter, with the spores produced likely to cause EAA.

Farmer’s lung can be prevented by drying crops adequately before storage and by ensuring good ventilation during storage. Respiratory protection should also be worn by farm workers when handling stored crops, particularly if they have been stored damp or are likely to be mouldy.

A single dose of intravenous magnesium sulphate is safe and may improve lung function and reduce intubation rates in patients with acute severe asthma. Intravenous magnesium sulphate may also reduce hospital admissions in adults with acute asthma who have had little or no response to standard treatment.

Consider giving a single dose of intravenous magnesium sulphate to patients with acute severe asthma (PEF <50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy. Magnesium sulphate (1.2–2 g IV infusion over 20 minutes) should only be used following consultation with senior medical staff.

Methyldopa is the drug of first choice for the control of mild to moderate hypertension in pregnancy. Labetalol is also considered as a first line drug for hypertension in pregnancy. Calcium channel blockers and hydralazine are considered as second line drugs. Beta-blockers (except labetalol), angiotensin receptor blockers, angiotensin-converting enzyme inhibitors and thiazides are not recommended.

Cholecystokinin (CCK) was discovered in 1928 in jejunal extracts as a gallbladder contraction factor. It was later shown to be member of a peptide family, which are all ligands for the CCK1 and CCK2 receptors. CCK peptides are known to be synthetized in the small intestinal endocrine I-cells and cerebral neurons.

The patient has acute promyelocytic leukaemia (APML) with associated disseminated intravascular coagulation (DIC). Although
the platelet count is high, platelet function is ineffective.

Patients may present, as in this case, with severe bleeding, and the most appropriate emergency treatment would be administration of fresh frozen plasma (FFP).

A case-control study is designed to help determine if an exposure is associated with an outcome (i.e., disease or condition of interest). In theory, the case-control study can be described simply. Case-control studies have specific advantages compared to other study designs. They are comparatively quick, inexpensive, and easy. They are particularly appropriate for (1) investigating outbreaks, and (2) studying rare diseases or outcomes. Sudden infant death syndrome is a rare medical event, thus case-control study is the most suitable option.

Pneumonitis is a serious and unpredictable side-effect of treatment with methotrexate (MTX) that may become life-threatening. The typical clinical symptoms include progressive shortness of breath and cough, often associated with fever. Hypoxaemia and tachypnoea are always present and crackles are frequently audible. Chest radiography reveals a diffuse interstitial or mixed interstitial and alveolar infiltrate, with a predilection for the lower lung fields. Pulmonary function tests show a restrictive pattern with diminished diffusion capacity. Lung biopsy reveals cellular interstitial infiltrates, granulomas or a diffuse alveolar damage pattern accompanied by perivascular inflammation. Most patients present in the first few months of starting methotrexate. It is important that all patients receiving methotrexate be educated concerning this potential adverse reaction and instructed to contact their physicians should significant new pulmonary symptoms develop while undergoing therapy. If methotrexate pneumonitis is suspected, methotrexate should be discontinued, supportive measures instituted and careful examination for different causes of respiratory distress conducted. This may be treated with corticosteroids once underlying infection has been excluded.

Porphyria cutanea tarda (PCT) is the most common of the porphyries. It is characterised by fragility and blistering of exposed skin. Typically, patients who are ultimately diagnosed with PCT first seek treatment following the development photosensitivities in the form of blisters and erosions on commonly exposed areas of the skin. This is usually observed in the face, hands, forearms, and lower legs. It heals slowly and with scarring. Though blisters are the most common skin manifestations of PCT, other skin manifestations like hyperpigmentation (as if they are getting a tan) and hypertrichosis (mainly on top of the cheeks) also occur. Risk factors for the development of PCT include alcohol and sun.

NPV = TN / FN+TN

= TN (true negative) / FN+TN (false negative + true negative)

= Probability (patient not having disease when test is negative)

Adverse effects due to IFN-alpha have been described in almost every organ system. Many side-effects are clearly dose-dependent. Taken together, occurrence of flu-like symptoms, haematological toxicity, elevated transaminases, nausea, fatigue, and psychiatric sequelae are the most frequently encountered side effects.

Silicosis is a common occupational lung disease that is caused by the inhalation of crystalline silica dust. Silica is the most abundant mineral on earth. Workers that are involved for example in construction, mining, or glass production are among the individuals with the highest risk of developing the condition. Acute silicosis causes severe symptoms (e.g., exertional dyspnoea, cough with sputum) and has a very poor prognosis.
Chronic silicosis has a very variable prognosis and affected individuals may remain asymptomatic for several decades. However, radiographic signs are usually seen early on. Typical radiographic findings are calcifications of perihilar lymph nodes, diffuse ground glass opacities, large numbers of rounded, solitary nodules or bigger, confluent opacities. Avoiding further exposure to silica is crucial, especially since the only treatment available is symptomatic (e.g., bronchodilators). Silicosis is associated with an increased risk of tuberculosis and lung cancer. Berylliosis typically affects individuals who are exposed to aerospace industry. Histoplasmosis and tuberculosis do not form eggshell calcifications.

Heterochromia (difference in iris colour) is seen in congenital Horner’s syndrome, as well as anhidrosis. Other features of non-congenital Horner’s include miosis, ptosis and enophthalmos.

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.

The water deprivation test (i.e., the Miller-Moses test), is a semiquantitative test to ensure adequate dehydration and maximal stimulation of ADH for diagnosis. It is typically performed in patients with more chronic forms of Diabetes Insipidus (DI). The extent of deprivation is usually limited by the patient’s thirst or by any significant drop in blood pressure or related clinical manifestation of dehydration.

In healthy individuals, water deprivation leads to a urinary osmolality that is 2-4 times greater than plasma osmolality. Additionally, in normal, healthy subjects, administration of ADH produces an increase of less than 9% in urinary osmolality. The time required to achieve maximal urinary concentration ranges from 4-18 hours.

In central and nephrogenic DI, urinary osmolality will be less than 300 mOsm/kg after water deprivation. After the administration of ADH, the osmolality will rise to more than 750 mOsm/kg in central DI but will not rise at all in nephrogenic DI. In primary polydipsia, urinary osmolality will be above 750 mOsm/kg after water deprivation.
A urinary osmolality that is 300-750 mOsm/kg after water deprivation and remains below 750 mOsm/kg after administration of ADH may be seen in partial central DI, partial nephrogenic DI, and primary polydipsia.

Illness anxiety disorder (IAD) is a recent term for what used to be diagnosed as hypochondriasis, or hypochondrial disorder. People diagnosed with IAD strongly believe they have a serious or life-threatening illness despite having no, or only mild, symptoms.

Symptoms of IAD may include:
-Excessive worry over having or getting a serious illness.
-Physical symptoms are not present or if present, only mild. If another illness is present, or there is a high risk for developing an illness, the person’s concern is out of proportion.
-High level of anxiety and alarm over personal health status.
-Excessive health-related behaviours (e.g., repeatedly checking body for signs of illness) or shows abnormal avoidance (e.g., avoiding doctors’ appointments and hospitals).
-Fear of illness is present for at least six months (but the specific disease that is feared may change over that time).
-Fear of illness is not due to another mental disorder.

Normal cerebrospinal fluid (CSF) glucose together with lymphocytosis, an increased opening pressure and raised CSF protein are typical of a viral meningitis.

Motor neuron disease is a neurological condition of unknown cause which can present with both upper and lower motor neuron signs. It rarely presents before age 40 and various patterns of disease are recognised, including amyotrophic lateral sclerosis, progressive muscular atrophy and bulbar palsy.
Non-invasive ventilation (usually BIPAP) is used at night, with studies having shown a survival benefit of around 7 months. Riluzole prevents stimulation of glutamate receptors, used mainly in amyotrophic lateral sclerosis and has been shown to prolong life by about 3 months.

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.

Signs and symptoms of baby blues may include:
Mood swings
Anxiety
Sadness
Irritability
Feeling overwhelmed
Crying
Reduced concentration
Appetite problems
Trouble sleeping

The exact cause of the “baby blues” is unknown at this time. It is thought to be related to the hormone changes that occur during pregnancy and again after a baby is born. These hormonal changes may produce chemical changes in the brain that result in depression.
Although the experience of baby blues is unpleasant, the condition usually subsides within two weeks without treatment. All the mom needs is reassurance and help with the baby and household chores.

All the above side-effects, with the exception of alopecia, may be seen in patients taking lithium.

Common lithium side effects may include:
– dizziness, drowsiness;
– tremors in your hands;
– trouble walking;
– dry mouth, increased thirst or urination;
– nausea, vomiting, loss of appetite, stomach pain;
– cold feeling or discoloration in your fingers or toes;
– rash; or.
– blurred vision.

Approximately one third of patients treated with radioiodine therapy develop transient hypothyroidism. Unless a patient is highly symptomatic, thyroxine replacement may be withheld if hypothyroidism occurs within the first 2 months of therapy. If it persists for longer than 2 months, permanent hypothyroidism is likely and replacement with T4 should be initiated.

Triptans are specific 5-HT1 agonists used in the acute treatment of migraine. They are generally used as first-line therapy in combination with an NSAID or paracetamol.

The immunological changes in HIV include depletion in CD4+ T cell, cytokine dysregulation and immune dysfunction. The dominant immunologic feature of HIV infection is progressive depletion of the helper T cell (CD4+ T cell), which reverses the normal CD4:CD8 ratio and subsequently lead to immunodeficiency. Other imuunological changes include:
increased B2-microglobulin
decreased IL-2 production
polyclonal B-cell activation
decreased NK cell function
reduced delayed hypersensitivity responses

Thrombolytic therapy is indicated in patients with evidence of ST-segment elevation MI (STEMI) or presumably new left bundle-branch block (LBBB) presenting within 12 hours of the onset of symptoms if there are no contraindications to fibrinolysis. STEMI is defined as new ST elevation at the J point in at least two contiguous leads of 2 mm (0.2 mV) or more in men or 1.5 mm (0.15 mV) in women in leads V2-V3 and/or 1 mm (0.1 mV) or more in other contiguous limb leads.

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.

Primary amyloidosis is characterised by abnormal protein build-up in the tissues and organ such as the heart, liver, spleen, kidneys, skin, ligaments, and nerves. However, the most common cause of death in patients with primary amyloidosis is heart failure.

Retinal and cerebellar haemangiomas are key features of Von Hippel-Lindau syndrome. Retinal haemangiomas are bilateral in 25% of patients and may lead to vitreous haemorrhage. Von Hippel-Lindau (VHL) syndrome is an autosomal dominant condition predisposing to neoplasia. It is due to an abnormality in the VHL gene located on short arm of chromosome 3.

Achondroplasia is the most common type of short-limb disproportionate dwarfism. A single gene mapped to the short arm of chromosome 4 (band 4p16.3) is responsible for achondroplasia and is transmitted as an autosomal dominant trait. All people with achondroplasia have a short stature.
Characteristic features of achondroplasia include an average-size trunk, short arms and legs with particularly short upper arms and thighs, limited range of motion at the elbows, and an enlarged head (macrocephaly) with a prominent forehead. Fingers are typically short and the ring finger and middle finger may diverge, giving the hand a three-pronged (trident) appearance. People with achondroplasia are generally of normal intelligence.
Examination of the infant after birth shows increased front-to-back head size. There may be signs of hydrocephalus. It may be diagnosed radiographically at birth, or becomes obvious within the first year with disparity between a large skull, normal trunk length and short limbs.

The patient has paroxysmal nocturnal haemoglobinuria (PNH). The classic sign of the disease is red discolouration of the urine due to the presence of haemoglobin and hemosiderin from the breakdown of red blood cells. As the urine is more concentrated in the morning, this is when the colour is most pronounced.

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combinations of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

Blue tinge of vision/cyanopsia is caused due to the intake of sildenafil citrate.

Sildenafil citrate (Viagra) is the first oral drug to be widely approved for the treatment of erectile dysfunction.
It is a potent and selective inhibitor of type-V phosphodiesterase, the primary form of the enzyme found in human penile erectile tissue, thereby preventing the breakdown of cyclic guanosine monophosphate (cGMP), the intracellular second messenger of nitric oxide.

Uses:
It is used for the treatment of erectile dysfunction, idiopathic pulmonary hypertension, premature ejaculation, high altitude illness, penile rehabilitation after radical prostatectomy, angina pectoris, and lower urinary tract symptoms.

Adverse effects:
Mild headache, flushing, dyspepsia, cyanopsia, back pain, and myalgias – due to a high concentration of PDE11 enzyme in skeletal muscle, which shows significant cross-reactivity with the use of tadalafil.
It can also cause hypotension, dizziness, and rhinitis.

Note: Xanthopsia (yellow-green vision) may occur secondary to treatment with digoxin.