N-acetylcysteine depletes glutathione reserves by providing cysteine, which is an essential precursor in glutathione production.

Glutathione within the liver can normally detoxify these minuscule quantities of NAPQI and prevent tissue damage.
N-acetylcysteine (NAC) is the mainstay of therapy for acetaminophen toxicity.

Paracetamol overdose:
The liver normally conjugates paracetamol with glucuronic acid/sulphate. During an overdose, the conjugation system becomes saturated leading to oxidation by cytochrome P450 (predominately CYP2E1) mixed-function oxidases. This produces a toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI).

Normally glutathione acts as a defence mechanism by conjugating with the toxin forming the non-toxic mercapturic acid. If glutathione stores run-out, the toxin forms covalent bonds with cell proteins, denaturing them and leading to cell death.

Other uses: In COPD, cystic fibrosis, and other lung conditions, nebulized NAC has mucolytic, anti-inflammatory, and antioxidant properties.

This patient has developed a venous sinus thrombosis peri-partum, resulting in her symptoms. Anticoagulation therapy including Heparin improves outcomes.

Immune thrombocytopenic purpura (ITP) refers to thrombocytopaenia occurring in the absence of toxic exposure or other diseases associated with low platelets and involves IgG-type antibodies. It is characterised by normal or increased marrow megakaryocytes, shortened platelet survival, and the absence of splenomegaly. Autoimmune haemolytic anaemia (AIHA) occurs commonly in association with ITP. Leukemic transformation, however, does not occur in ITP.

In neonatal ITP, IgG antibodies are passively transferred across the placenta. The infant platelet count may be normal at birth but decreases within 12–24 hours. It is rarely severe enough to induce bleeding diathesis in the infant.

The development of hepatic fibrosis reflects an alteration in the normally balanced processes of extracellular matrix production and degradation. [6] The extracellular matrix, the normal scaffolding for hepatocytes, is composed of collagens (especially types I, III, and V), glycoproteins, and proteoglycans. Increased collagen in the space of Disse (space b/w sinusoids and hepatocytes) leads to capillarization of sinusoids, and stellate cells also have contractile properties when activated. This is fibrosis processes. This can lead to the development of portal hypertension.

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.

Central chemoreception refers to the detection of changes in CO2/H+ within the brain and the associated effects on breathing. In the conscious animal the response of ventilation to changes in the brain’s interstitial fluid (ISF) pH is very sensitive. Note that a small change in cerebrospinal fluid (CSF) pH from 7.30 to 7.25 is associated with a doubling of alveolar ventilation; it is a very sensitive reflex response. Note also that the relationship of alveolar ventilation to ISF pH is essentially the same for both types of stimulation, metabolic acid-base disorders and primary CO2 stimulation.

The classes refer to the WHO classification of glomerulonephritis in SLE patients.
class I: normal kidney
class II: mesangial glomerulonephritis
class III: focal (and segmental) proliferative glomerulonephritis
class IV: diffuse proliferative glomerulonephritis
class V: diffuse membranous glomerulonephritis
class VI: sclerosing glomerulonephritis

Class IV: diffuse proliferative glomerulonephritis is the most common and the most severe form, where more than 50% of the glomeruli are involved.

PCR is a simple, yet elegant, enzymatic assay, which allows for the amplification of a specific DNA fragment from a complex pool of DNA. PCR can be performed using source DNA from a variety of tissues and organisms, including peripheral blood, skin, hair, saliva, and microbes. Only trace amounts of DNA are needed for PCR to generate enough copies to be analysed using conventional laboratory methods. For this reason, PCR is a sensitive assay. Each PCR assay requires the presence of template DNA, primers, nucleotides, and DNA polymerase. The DNA polymerase is the key enzyme that links individual nucleotides together to form the PCR product. The above mentioned components are mixed in a test tube or 96-well plate and then placed in a machine that allows repeated cycles of DNA amplification to occur in three basic steps. The machine is essentially a thermal cycler. It has a thermal block with holes, into which the test tubes or plates holding the PCR reaction mixture are inserted. The machine raises and lowers the temperature of the block in discrete, precise and pre-programmed steps. The reaction solution is first heated above the melting point of the two complementary DNA strands of the target DNA, which allows the strands to separate, a process called denaturation. The temperature is then lowered to allow the specific primers to bind to the target DNA segments, a process known as hybridization or annealing. Annealing between primers and the target DNA occurs only if they are complementary in sequence (e.g. A binding to G). The temperature is raised again, at which time the DNA polymerase is able to extend the primers by adding nucleotides to the developing DNA strand. With each repetition of these three steps, the number of copied DNA molecules doubles.

Retinitis pigmentosa is a genetic disorder of the eyes that causes loss of vision. Symptoms include trouble seeing at night and decreased peripheral vision. Onset of symptoms is generally gradual.
– In keratitis, there will be pain, redness and photophobia but vision is not affected
– In macular degeneration, near blindness does not occur rather the inability to identify faces or read small print
– Cataracts are more common in elderly
– It is not angle closure glaucoma as angle closure glaucoma occurs usually after the age of 50; In open angle glaucoma visual loss is not gradual but rather occurs suddenly following progression

A lucid interval, in which the patient portrays a temporary improvement in condition after a traumatic brain injury, is especially indicative of an epidural haematoma.

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.

Turner syndrome (TS) is one of the most common genetic disorders; occurs with an incidence of I: 2,500 female live births. It results from complete or partial chromosome X monosomy. TS is associated with abnormalities of the X chromosome and characteristic clinical features of short stature, gonadal dysgenesis, sexual developmental deficiencies, cardiac and/or renal defects, webbed neck, low-set ears, skeletal deformities including cubitus valgus, a propensity to ear infections and hearing deficits.

Diagnosis of RA is mainly based on clinical features (e.g., morning stiffness, symmetrical joint swelling) and laboratory tests (e.g., anti-CCP). Rheumatoid factor is not very specific for this disease and hence has low reliability. X-ray findings (e.g., soft tissue swelling or joint space narrowing) occur late in the disease and are therefore not typically used for diagnosis.

The most common type of Hodgkin’s lymphoma (HL) is nodular sclerosing.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

According to the histological classification, there are four types of HL:

1. Nodular sclerosing: most common (around 70%), more common in women, associated with lacunar cells, good prognosis

2. Mixed cellularity: Around 20%, associated with a large number of Reed-Sternberg cells, good prognosis

3. Lymphocyte-predominant: Around 5%, Reed-Sternberg cells with nuclei surrounded by a clear space found, best prognosis

4. Lymphocyte-depleted: rare, worst prognosis

Cabergoline, an ergot derivative, is a long-acting dopamine agonist. It is usually better tolerated than Bromocriptine (BEC), and its efficacy profiles are somewhat superior to those of BEC. It offers the convenience of twice-a-week administration, with a usual starting dose of 0.25 mg biweekly to a maximum dose of 1 mg biweekly. Some studies have shown efficacy even with once-a-week dosing. Cabergoline appears to be more effective in lowering prolactin levels and restoring ovulation. Up to 70% of patients who do not respond to BEC respond to cabergoline.

Hyperacute rejection appears in the first minutes following transplantation and occurs only in vascularized grafts. This very fast rejection is characterized by vessel thrombosis leading to graft necrosis. Hyperacute rejection is caused by the presence of antidonor antibodies existing in the recipient before transplantation. These antibodies induce both complement activation and stimulation of endothelial cells to secrete Von Willebrand procoagulant factor, resulting in platelet adhesion and aggregation. The result of these series of reactions is the generation of intravascular thrombosis leading to lesion formation and ultimately to graft loss. Today, this type of rejection is avoided in most cases by checking for ABO compatibility and by excluding the presence of antidonor human leukocyte antigen (HLA) antibodies by cross-match techniques between donor graft cells and recipient sera. This type of rejection is also observed in models of xenotransplantation of vascularized organs between phylogenetically distant species when no immunosuppressive treatment is given to the recipients.

The patient most likely suffers from Paget’s disease of the bone as his radiological examination shows both osteolytic and osteosclerotic lesions. Any bone or bones can be affected, but Paget’s disease occurs most frequently in the pelvis > lumbar spine > femur > thoracic spine > sacrum > skull > tibia.

The level of haemoglobin A1c (HbA1c), also known as glycated haemoglobin, determines how well a patient’s blood glucose level has been controlled over the previous 8–12 weeks. Recent studies have been made to correlate between HbA1c and average glucose level.
Using the following formula: Average blood glucose (mmol/l) = (1.98 x 1 HbA1c) – 4.29

Live virus vaccines include: Vaccinia (smallpox), Measles, Mumps, Rubella (MMR combined vaccine), Varicella (chickenpox), Influenza (nasal spray), Rotavirus, Zoster (shingles) and Yellow fever. Inactivated vaccines are Polio (IPV), Hepatitis A and Rabies.

Hypertrophic cardiomyopathy is an autosomal dominant condition. Patients present with sudden cardiac death, dyspnoea, syncope and presyncope, angina, palpitations, orthopnoea and paroxysmal nocturnal dyspnoea, Congestive heart failure and dizziness. Physical findings include double or triple apical impulse, prominent a wave in the JVP, an ejection systolic crescendo-decrescendo murmur and a holosystolic murmur at the apex and axilla of mitral regurgitation.
ECG shows ST-T wave abnormalities and LVH, axis deviation (right or left), conduction abnormalities (P-R prolongation, bundle-branch block), sinus bradycardia with ectopic atrial rhythm, atrial enlargement, abnormal and prominent Q wave in the anterior precordial and lateral limb leads.
2D echocardiography shows abnormal systolic anterior leaflet motion of the mitral valve, LVH, left atrial enlargement, small ventricular chamber size, septal hypertrophy with septal-to-free wall ratio greater than 1.4:1, mitral valve prolapse and mitral regurgitation, decreased midaortic flow, partial systolic closure of the aortic valve in midsystole

Pulmonary alveolar proteinosis (PAP) is a lung condition that is caused by a build-up of proteins and other substances in the alveoli. The alveoli are the part of the lungs that contain air. PAP has the following symptoms:
Shortness of breath, also called dyspnoea
Chest pain or tightness
Fever
Weight loss
Cough (sometimes, but not always)
Low levels of oxygen in the blood
Nail clubbing (abnormal growth of toenails or fingernails)

Serologic studies are generally not useful for PAP. Flexible bronchoscopy with bronchoalveolar lavage (BAL) remains the criterion standard. Elevated levels of the proteins SP-A and SP-D in serum and BAL fluid may be useful. Elevated titer of neutralizing autoantibody against GM-CSF (immunoglobulin G [IgG] isotype) in serum and BAL fluid may be useful. Recent studies have proposed that deficiency of GM-CSF causes pulmonary alveolar proteinosis (PAP); all patients studied had the antibody to GM-CSF. Serum lactate dehydrogenase (LDH) level is usually elevated, but this finding is nonspecific.

High-resolution computed tomography (HRCT) scan of the chest demonstrates areas of patchy ground-glass opacification with smooth interlobular septal thickening and intralobular interstitial thickening, which produces a polygonal pattern referred to as crazy paving.

Light microscopy of the lung parenchymal tissue shows alveoli filled with a granular PAS base-reactive and diastase-resistant eosinophilic material.

Bradycardia and miosis should be anticipated following the administration of anticholinesterases.

Anticholinesterase agents include the following medications:
– Pyridostigmine, neostigmine, and edrophonium which play a significant role in the diagnosis and the management of myasthenia gravis.
– Rivastigmine, galantamine and donepezil are cholinesterase inhibitors found to be significantly useful in the management of Alzheimer’s disease.

Mechanism of action and pharmacological effects:
Inhibition of cholinesterase increases the level and the duration of action of acetylcholine within the synaptic cleft.

Thus, cholinergic effects such as a reduction in heart rate (bradycardia), miosis (pupillary constriction), increased secretions, increased gastrointestinal motility and reduction in BP may occur with anticholinesterases.

Toxins such as organophosphates and carbamates also are primarily anticholinergic and cause the following typical SLUDGE symptoms:
– Salivation
– Lacrimation
– Urination
– Diaphoresis
– Gastrointestinal upset
– Emesis

The vas deferens is a long tube that connects the epididymis to the ejaculatory ducts. It acts as a canal through which mature sperm may pass through the penis during ejaculation.

Most men with CF (97-98 percent) are infertile because of a blockage or absence of the vas deferens, known as congenital bilateral absence of the vas deferens (CBAVD). The sperm never makes it into the semen, making it impossible for them to reach and fertilize an egg through intercourse. The absence of sperm in the semen can also contribute to men with CF having thinner ejaculate and lower semen volume.

The antithrombotic action of aspirin is due to inhibition of platelet function by acetylation of the platelet cyclooxygenase (COX) at the functionally important amino acid serine529. This prevents the access of the substrate (arachidonic aid) to the catalytic site of the enzyme at tyrosine385 and results in an irreversible inhibition of platelet-dependent thromboxane formation.

The patient is most likely to have Addison’s disease as he has a history of autoimmune disease, hyperkalaemia and hypotension.
It is important to keep an Addisonian crisis on the differential in cases of shock, especially since adrenal crisis can be the patient’s first presentation of adrenal insufficiency.
Patients with Addison’s disease are prone to developing hypoglycaemia due to loss of the glucogenic effect of glucocorticoids. Given the sudden deterioration, a glucose level must be checked.

This patient shows classic symptoms of autosomal-dominant polycystic kidney disease (ADPKD). The abdominal pain and early satiety is caused by the enlarged kidneys that were apparent from the physical examination. Additionally, hypertension is a common symptom along with the systolic murmur that was heard, suggesting mitral valve involvement. In ADPKD cases, the most common extra-renal manifestation is the development of liver cysts which are associated with hepatomegaly.

Community-acquired pneumonia (CAP) is one of the most common infectious diseases and is an important cause of mortality and morbidity worldwide. Typical bacterial pathogens that cause CAP include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
The CURB-65 is used as a means of deciding the action that is needed to be taken for that patient.
Score 3-5: Requires hospitalization with consideration as to whether they need to be in the intensive care unit

Recent studies have suggested that the use of a beta-lactam alone may be noninferior to a beta-lactam/macrolide combination or fluoroquinolone therapy in hospitalized patients.

Therapy in ICU patients includes the following:
– Beta-lactam (ceftriaxone, cefotaxime, or ampicillin/sulbactam) plus either a macrolide or respiratory fluoroquinolone
– For patients with penicillin allergy, a respiratory fluoroquinolone and aztreonam

Therefore the appropriate treatment would be Cefotaxime and erythromycin.

Pulmonary metastasis is seen in 20-54% of extrathoracic malignancies. The lungs are the second most frequent site of metastases from extrathoracic malignancies. Twenty percent of metastatic disease is isolated to the lungs. The development of pulmonary metastases in patients with known malignancies indicates disseminated disease and places the patient in stage IV in TNM (tumour, node, metastasis) staging systems.
Chest radiography (CXR) is the initial imaging modality used in the detection of suspected pulmonary metastasis in patients with known malignancies. Chest CT scanning without contrast is more sensitive than CXR.
Breast, colorectal, lung, kidney, head and neck, and uterus cancers are the most common primary tumours with lung metastasis at autopsy. Choriocarcinoma, osteosarcoma, testicular tumours, malignant melanoma, Ewing sarcoma, and thyroid cancer frequently metastasize to lung, but the frequency of these tumours is low.

An escharotomy is a surgical procedure used to treat full-thickness (third-degree) circumferential burns. In full-thickness burns, both the epidermis and the dermis are destroyed along with sensory nerves in the dermis. The tough leathery tissue remaining after a full-thickness burn has been termed eschar.

This describes a clinical scenario of spontaneous bacterial peritonitis. The diagnosis is made when fluid removed (ascites) is found to have > 250/mm cubed of PMNs (polymorphonuclear leukocytes). Cefotaxime or another third generation cephalosporin is the treatment of choice.