The right and left lung anatomy are similar but asymmetrical. The right lung consists of three lobes: right upper lobe (RUL), right middle lobe (RML), and right lower lobe (RLL). The left lung consists of two lobes: right upper lobe (RUL) and right lower lobe (RLL). The right lobe is divided by an oblique and horizontal fissure, where the horizontal fissure divides the upper and middle lobe, and the oblique fissure divides the middle and lower lobes. In the left lobe there is only an oblique fissure that separates the upper and lower lobe.

The lobes further divide into segments which are associated with specific segmental bronchi. Segmental bronchi are the third-order branches off the second-order branches (lobar bronchi) that come off the main bronchus.

The right lung consists of ten segments. There are three segments in the RUL (apical, anterior and posterior), two in the RML (medial and lateral), and five in the RLL (superior, medial, anterior, lateral, and posterior). The oblique fissure separates the RUL from the RML, and the horizontal fissure separates the RLL from the RML and RUL.

There are eight to nine segments on the left depending on the division of the lobe. In general, there are four segments in the left upper lobe (anterior, apicoposterior, inferior and superior lingula) and four or five in the left lower lobe (lateral, anteromedial, superior and posterior). The medium sized airways offer the maximum airway resistance, not smaller ones.

Drug metabolism can be broadly classified into:
Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.

Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.

Inherited metabolic disorders are often characterized by the lack of an essential enzyme and are currently treated by dietary restriction and other strategies to replace the substrates or products of the missing enzyme. Patients with homocystinuria lack the enzyme cystathionine β-synthase (CBS), and many of these individuals do not respond to current treatment protocols.

Hypothermia is defined as a core body temperature of < 35 °C.
Hypothermia may produce the following ECG changes:
-Bradyarrhythmia
-Osborne Waves (= J waves)
-Prolonged PR, QRS and QT intervals
-Shivering artefact
-Ventricular ectopics
-Cardiac arrest due to VT, VF or asystole

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).

Waldenström’s macroglobulinemia (also called lymphoplasmacytic lymphoma) is an uncommon type of non-Hodgkin lymphoma seen in older people. It is a lymphoplasmacytoid malignancy characterised by the secretion of a monoclonal IgM paraprotein. Its features include weight loss and lethargy; monoclonal IgM paraproteinemia; hyperviscosity syndrome leading to bilateral central retinal vein occlusion (CRVO) and hence, visual disturbances; hepatosplenomegaly and lymphadenopathy; and cryoglobulinemia. It is not, however, associated with bone pain.

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

A fasting blood glucose level from 110 to 126 mg/dL (5.5 to 6.9 mmol/L) is considered prediabetes. This result is sometimes called impaired fasting glucose.
Diabetes mellitus (type 2): diagnosis

The diagnosis of type 2 diabetes mellitus can be made by plasma glucose. If the patient is symptomatic:
fasting glucose greater than or equal to 7.0 mmol/l
random glucose greater than or equal to 11.1 mmol/l (or after 75g oral glucose tolerance test)
If the patient is asymptomatic the above criteria apply but must be demonstrated on two separate occasions.

The dose is calculated, using the conversion factor, as follows:

(Conversion factor used to convert oral morphine to subcutaneous diamorphine = Divide the total daily dose of oral morphine by 3)
Hence,
60mg*2 = 120mg
120mg/3 = 40mg

The side effects of opioids can be transient or persistent, and these include constipation, nausea, and drowsiness. Therefore, all patients taking opioids should also be prescribed a laxative and an anti-emetic (if the nausea is persistent). Dose-adjustment may be necessary in cases of persistent drowsiness. Moreover, strong opioids can also provide quick relief from metastatic bone pain, as compared to NSAIDs, bisphosphonates, and radiotherapy.

Elevated TSH (usually 4.5-10.0 mIU/L) with normal free T4 is considered mild or subclinical hypothyroidism.
Hypothyroidism commonly manifests as a slowing in physical and mental activity but may be asymptomatic. Symptoms and signs are often subtle and neither sensitive nor specific.
The following are symptoms of hypothyroidism:
– Fatigue, loss of energy, lethargy
– Weight gain
– Decreased appetite
– Cold intolerance
– Dry skin
– Hair loss
– Sleepiness
– Muscle pain, joint pain, weakness in the extremities
– Depression
– Emotional lability, mental impairment
– Forgetfulness, impaired memory, inability to concentrate
– Constipation
– Menstrual disturbances, impaired fertility
– Decreased perspiration
– Paraesthesia and nerve entrapment syndromes
– Blurred vision
– Decreased hearing
– Fullness in the throat, hoarseness
Physical signs of hypothyroidism include the following:
– Weight gain
– Slowed speech and movements
– Dry skin
– Jaundice
– Pallor
– Coarse, brittle, straw-like hair
– Loss of scalp hair, axillary hair, pubic hair, or a combination
– Dull facial expression
– Coarse facial features
– Periorbital puffiness
– Macroglossia
– Goitre (simple or nodular)
– Hoarseness
– Decreased systolic blood pressure and increased diastolic blood pressure
– Bradycardia
– Pericardial effusion
– Abdominal distention, ascites (uncommon)
– Hypothermia (only in severe hypothyroid states)
– Nonpitting oedema (myxoedema)
– Pitting oedema of lower extremities
– Hyporeflexia with delayed relaxation, ataxia, or both.

The empty boxes indicate that the patient has run out of his medication.
Chronic administration of high doses of glucocorticoids (GCs) (e.g., prednisone or prednisolone) and also other hormones such as oestrogens, progestins, androgens and growth hormone induce varying degrees of tolerance, resulting in a progressively decreased response to the effect of the drug, followed by dependence and rarely addiction.
The glucocorticoid withdrawal syndrome (GWS) has been considered a withdrawal reaction due to established physical dependence on supraphysiological GC levels.
The severity of GWS depends on the genetics and developmental history of the patient, on his environment, and on the phase and degree of dependence the patient has reached. Its management should include a temporary increase in the dose of GCs followed by gradual, slow tapering to a maintenance dose.

The history of diabetes, complete loss of vision in the affected eye and inability to visualise the retina, suggest a diagnosis of vitreous haemorrhage (VH). 3 conditions cause 59 to 88.5% of VH cases: proliferative diabetic retinopathy, posterior vitreous detachment (PVD), and ocular trauma

Severe vitamin C deficiency results in scurvy, a disorder characterized by hemorrhagic manifestations and abnormal osteoid and dentin formation.
Vitamin C plays a role in collagen, carnitine, hormone, and amino acid formation. It is essential for bone and blood vessel health and wound healing and facilitates recovery from burns. Vitamin C is also an antioxidant, supports immune function, and facilitates the absorption of iron (see table Sources, Functions, and Effects of Vitamins).
Dietary sources of vitamin C include citrus fruits, tomatoes, potatoes, broccoli, strawberries, and sweet peppers. (See also Overview of Vitamins.)

Transposition of the great arteries results in a significant hypoxemic status that is observed clinically by central cyanosis. The bluish discoloration of the skin and mucous membranes is therefore the basic pattern of clinical presentation in transposition. Its onset and severity depend on anatomical and functional variants that influence the degree of mixing between the two circulations. Limited intercirculatory mixing, usually present if the ventricular septum is intact or the atrial septal defect is restrictive, is related to progressive and profound central cyanosis evident within the first hours of life. Tachypnoea, tachycardia, diaphoresis, poor weight gain, a gallop rhythm, and eventually hepatomegaly can be then detected later on during infancy. Heart murmurs associated with left outflow tract obstruction, due to a persistent arterial duct or a septal defect may be heard, but they are not a constant finding.

11-beta hydroxylase is stimulated by ACTH and responsible for conversion of 11-deoxycortisol to cortisol and deoxycorticosterone to corticosterone.

In 11-beta hydroxylase deficiency, the previously mentioned conversions are partially blocked, leading to:
– Increased levels of ACTH
– Accumulation of 11-deoxycortisol (which has limited biological activity) and deoxycorticosterone (which has mineralocorticoid activity)
– Overproduction of adrenal androgens (DHEA, androstenedione, and testosterone)

Polymyalgia rheumatica, a syndrome characterized by proximal muscle pain and stiffness in older persons, generally is treated with prednisone. Dosages of 15 to 25 mg of prednisone per day can reduce inflammation considerably, although many patients relapse when therapy is tapered. Long-term (18 to 36 months) steroid treatment has been recommended by several studies, but this can result in multiple side effects, including osteoporosis, hypertension, cataracts, and hyperglycaemia. Methotrexate has been used to reduce inflammation in rheumatoid arthritis, systemic vasculitis, and giant cell arteritis, and in some studies has been combined with prednisone to treat polymyalgia rheumatica, decreasing the duration of treatment.

TNF-alpha inhibitors are known to ameliorate the symptoms and disease activity of Arthritis mutilans (a rare and severe form of psoriatic arthritis), by disabling the cytokines that are involved in inflammation and joint destruction. From the mentioned choices, this would be the most effective option. Methotrexate is the most commonly used DMARD, followed by sulfasalazine used in mild to moderate forms of psoriatic arthritis but has not shown much efficacy in arthritis mutilans. Phototherapy, narrowband UVB light therapy can be very effective in clearing skin lesions.

You may treat chickenpox with acyclovir if it is commenced within the first 24 hours of the rash’s appearance. Erythromycin, doxycycline, and ampicillin would not help because it’s a viral infection (Varicella) not a bacterial infection.

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered. For patients at low risk of these symptoms, drugs such as metoclopramide may be used. For high-risk patients, however, 5-HT3 receptor antagonists such as ondansetron are often effective, especially if combined with dexamethasone.

Carcinoembryonic antigen (CEA) is a known tumour marker for colorectal cancer. It is not used diagnostically, but in patients with a known diagnosis of colorectal cancer associated with raised CEA levels, it can be used to monitor disease activity and help with the early identification of disease recurrence.

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)

Caplan’s syndrome is defined as the association between silicosis and rheumatoid arthritis (RA). It is rare and usually diagnosed in an advanced stage of RA. It generally affects patients with a prolonged exposure to silica.

Caplan’s syndrome presents with rheumatoid lung nodules and pneumoconiosis. Originally described in coal miners with progressive massive fibrosis, it may also occur in asbestosis, silicosis and other pneumoconiosis. Chest radiology shows multiple, round, well defined nodules, usually 0.5 – 2.0 cm in diameter, which may cavitate and resemble tuberculosis.

The most likely diagnosis is acute atrial fibrillation (AF) precipitated by acute pneumonia. History of fever, cough and the auscultation findings support it. So the most appropriate management is treating the pneumonia with antibiotics. Treating the underlying cause will reduce the heart rate. Other responses are helpful in the management of chronic AF.

This patient has a poorly controlled T2DM with an underlying diabetic nephropathy. The histological findings are Kimmelstiel-Wilson lesions (nodular glomerulosclerosis) and hyaline arteriosclerosis. This is due to nonenzymatic glycosylation.

Diabetic nephropathy is the chronic loss of kidney function occurring in those with diabetes mellitus. Protein loss in the urine due to damage to the glomeruli may become massive, and cause a low serum albumin with resulting generalized body swelling (edema) and result in the nephrotic syndrome. Likewise, the estimated glomerular filtration rate (eGFR) may progressively fall from a normal of over 90 ml/min/1.73m2 to less than 15, at which point the patient is said to have end-stage kidney disease (ESKD). It usually is slowly progressive over years.

Nephrotic syndrome usually presents with the symptoms in this patient: low albumin, abnormal cholesterol, increased urinary albumin excretion, oedema, and as a consequence, hypertension as well.

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.

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 most sensitive test for detecting Hepatitis C infection (acute) is HCA RNA; it can be detected 1-2 weeks after infection. Anti-HCV antibodies take at least 6 weeks to develop and be positive.

Renal elimination of a drug has no role in altering the bioavailability of a drug.
The bioavailability of a drug is the proportion of the drug which reaches systemic circulation.
Mathematically, bioavailability is the AUCoral/AUCiv x 100%, where AUC = area under the concentration-time curve following a single (oral or iv) dose.

Other options are true:
By definition, the bioavailability of a drug given intravenously is 100%.
Drugs given orally that undergo high pre-systemic (first-pass) metabolism in the liver or gut wall have a low bioavailability e.g. lidocaine.
Bioavailability is also affected by the degree of absorption from the gut and this can change depending on gut motility and administration of other drugs.

According to echocardiography findings pulmonary pressure is closer to systemic blood pressure and it is evidence of pulmonary hypertension. Because of the reversal of shunt due to pulmonary hypertension, cyanosis and clubbing have developed. So the most probable diagnosis is Eisenmenger’s syndrome.

For medical management of carcinoid syndrome, there are two somatostatin analogues available, Octreotide and Lanreotide. Somatostatin is an amino acid peptide which is an inhibitory hormone, which is synthesized by paracrine cells located ubiquitously throughout the gastrointestinal tract. Both somatostatin analogues provide symptom relief in 50% to 70% of patients and biochemical response in 40% to 60% patients. Many studies have shown that Octreotide and Lanreotide also inhibit the proliferation of tumour cells.