Heroin is injected into the veins and is the most commonly abused drug. Acute intoxication with opioid overuse is the most common cause of death by drug overdose.

The clinical features of opioid overdose are:
1. Decreased respiratory rate
2. Reduced conscious level or coma
3. Decreased bowel sounds
4. Miotic (constricted) pupils
5. Cyanosis
6. Hypotension
7. Seizures
8. Non-cardiogenic pulmonary oedema (with IV heroin usage)

The main cause of death secondary to opioid overdose is respiratory depression, which usually occurs within 1 hour of the overdose. Vomiting is also common, and aspiration can occur.

Naloxone is a short-acting, specific antagonist of mu(μ)-opioid receptors. It is used to reverse the effects of opioid toxicity.

It can be given by a continuous infusion if repeated doses are required and the infusion rate is adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.

Naloxone has a shorter duration of action (6-24 hours) than most opioids, and so close monitoring according to the respiratory rate and depth of coma with repeated injections is necessary. When repeated doses are needed in opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours.

An initial dose of 0.4 to 2 mg can be given intravenously and can be repeated at 2 to 3-minute intervals to a maximum of 10mg.

If the intravenous route is inaccessible, naloxone can be administered via an IO line, subcutaneously (SQ), IM, or via the intranasal (IN) route.

Cryptococcus neoformans typically causes a chronic lymphocytic meningitis in immunosuppressed patients or those with intense exposure e.g. pigeon fanciers.

Pectoralis minor is a thin, triangular muscle that is situated in the upper chest. It is thinner and smaller than pectoralis major. It is innervated by the medial pectoral nerve.
The origin of pectoralis minor is the 3rdto the 5thribs, near the costal cartilages. It inserts into the medial border and superior surface of the coracoid process of the scapula.
The main action of pectoralis minor is to draw the scapula inferiorly and anteriorly against the thoracic wall. This serves to stabilise the scapula.

Lacrimal fluid is drained from the eyeball through the lacrimal punctum.

An audit assesses if a certain aspect of health care is attaining a recognized standard. This lets care providers and patients know where their service is doing well, and where there could be improvements. The aim is to achieve quality improvement and improve outcomes for patients.

Audits are a quality improvement measure and one of the 7 pillars of clinical governance. It allows organizations to continually work toward improving quality of care by showing them where they are falling short, allows them to implement improvements, and reaudit or close the audit cycle to see if beneficial change has taken place.

Clinical audits are a cycle with several steps:

1. Identification of the problem
2. Definition of criteria and setting of standards
3. Observation of practice and collection of data
4. Analysis of data and comparison of performance with the criteria and standards
5. Implementation of change

Hodgkin’s lymphoma is a malignant tumour of the lymphatic system that is characterised histologically by the presence of Reed-Sternberg cells (multinucleated giant cells). The peak incidence is in young adults aged 20-35, and there is a slight male predominance.

The following are recognised risk factors for Hodgkin’s lymphoma:
Male gender
Age 20-35
Positive family history
Epstein-Barr virus infection
Immunosuppression including HIV infection
Prolonged use of human growth hormone
Most patients present with an enlarged, but otherwise asymptomatic lymph node. The most commonly affected lymph nodes are in the supraclavicular and lower cervical areas. Other common clinical features include shortness of breath and chest discomfort secondary to mediastinal mass. Mediastinal masses are sometimes discovered as incidental findings on routine chest X-rays. Approximately 30% of patients with Hodgkin’s lymphoma develop splenomegaly.
‘B’ symptoms occur in approximately 25% of patients. The ‘B’ symptoms of Hodgkin’s lymphoma are:
Fever (>38ºC)
Night sweats
Weight loss (>10% over 6 months)
Pain after alcohol consumption is a pathognomonic sign of Hodgkin’s lymphoma, it is, however, not a ‘B’ symptom. It is rare though, only occurring in 2-3% of patients with Hodgkin’s lymphoma.

The Ann Arbour clinical staging is as follows:
Stage I: one involved lymph node group
Stage II two involved lymph node groups on one side of the diaphragm
Stage III: lymph node groups involved on both sides of the diaphragm
Stage IV: Involvement of extra-nodal tissues, such as the liver or bone marrow
Diagnosis is made by lymph node biopsy, which should be taken from a sufficiently large specimen or excisional biopsy, as opposed to a fine needle biopsy. The Reed-Sternberg cell is the most useful diagnostic feature. This is a giant cell with twin mirror-image nuclei and prominent ‘owl’s eye’ nucleoli.
The Reed-Sternberg cell of Hodgkin’s Lymphoma
Histological typing depends upon the other cells within the diseased tissue. Nodular sclerosing is the most common type of Hodgkin’s lymphoma. Lymphocyte-depleted and lymphocyte-predominant are rare subtypes.
The majority of cases can be successfully treated, and unlike many other malignancies even if the first-line treatment fails, a cure can often be achieved with second-line therapies. Stage 1 Hodgkin’s lymphoma is usually treated with radiotherapy alone, but more advanced stages require combination chemotherapy. In localised disease treated with irradiation, there is a 5-year survival rate of greater than 80%. In disseminated disease treated with chemotherapy, the 5-year survival falls to around 50%. Overall, a 5-year survival of >70% should be achieved.

Pilocytic astrocytoma (PCA), previously known as cystic cerebellar astrocytoma or juvenile pilocytic astrocytoma, was first described in 1931 by Harvey Cushing, based on a case series of cerebellar astrocytomas; though he never used these terms but rather described a spongioblastoma. They are low-grade, and usually well-circumscribed tumours, which tend to occur in young patients. By the World Health Organization (WHO) classification of central nervous system tumours, they are considered grade I gliomas and have a good prognosis.

PCA most commonly occurs in the cerebellum but can also occur in the optic pathway, hypothalamus, and brainstem. They can also occur in the cerebral hemispheres, although this tends to be the case in young adults. Presentation and treatment vary for PCA in other locations. Glial cells include astrocytes, oligodendrocytes, ependymal cells, and microglia. Astrocytic tumours arise from astrocytes and are the most common tumour of glial origin. The WHO 2016 categorized these tumours as either diffuse gliomas or other astrocytic tumours. Diffuse gliomas include grade II and III diffuse astrocytomas, grade IV glioblastoma, and diffuse gliomas of childhood. The other astrocytic tumours group include PCA, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, and anaplastic pleomorphic xanthoastrocytoma.

PCA can present with symptoms secondary to the posterior fossa mass effect. This may include obstructive hydrocephalus, with resultant headache, nausea and vomiting, and papilledema. If hydrocephalus occurs before the fusion of the cranial sutures (<18-months-of-age), then an increase in head circumference will likely occur. Lesions of the cerebellar hemisphere result in peripheral ataxia, dysmetria, intention tremor, nystagmus, and dysarthria. In contrast, lesions of the vermis cause a broad-based gait, truncal ataxia, and titubation. Posterior fossa lesions can also cause cranial nerve palsies. Diplopia may occur due to abducens palsy from the stretching of the nerve. They may also have blurred vision due to papilledema. Seizures are rare with posterior fossa lesions.

In addition to the sodium chloride 0.9 percent infusion, glucose 10% should be given intravenously (into a large vein with a large-gauge needle) at a rate of 125 mL/hour once blood glucose concentration falls below 14 mmol/litre.

Antacids should preferably not be taken at the same time as other drugs since they may impair absorption. Antacids act by neutralising stomach acid. They are used for symptomatic relief in dyspepsia, but are not first line for proven peptic ulcer disease where antisecretory drugs have a better healing effect. Magnesium-containing antacids tend to be laxative whereas aluminium-containing antacids tend to be constipating. Antacids are contraindicated in hypophosphataemia.

Klebsiellais a genus of non-motile,Gram-negative, rod-shaped bacteriawith a prominent polysaccharide-based capsule. They are routinely found in the nose, mouth and gastrointestinal tract as normal flora, however, they can also behave as opportunistic pathogens.
Infections with Klebsiella spp. areusually nosocomial. They are an important cause of ventilator-associated pneumonia (VAP), urinary tract infection, wound infection and bacteraemia. Outbreaks of infections with Klebsiellaspp. in high-dependency units have been described and are associated with septicaemia and high mortality rates. Length of hospital stay and performance of invasive procedures are risk factors forKlebsiellainfections.
Primary pneumonia withKlebsiella pneumoniaeis a rare,severe, community-acquired infection associated with a poor outcome.
Klebsiella rhinoscleromatis causes a progressive granulomatous infection of the nasal passages and surrounding mucous membranes. This infection is mainly seen in the tropics.
Klebsiella ozanae is a recognised cause of chronic bronchiectasis.
Klebsiella organisms are resistant to multiple antibiotics including penicillins. This is thought to be a plasmid-mediated property. Agents with high intrinsic activity againstKlebsiellapneumoniaeshould be selected for severely ill patients. Examples of such agents include third-generation cephalosporins (e.g cefotaxime), carbapenems (e.g. imipenem), aminoglycosides (e.g. gentamicin), and quinolones (e.g. ciprofloxacin). These agents may be used as monotherapy or combination therapy. Aztreonam may be used in patients who are allergic to beta-lactam antibiotics.
Species with ESBLs (Extended spectrum beta-lactamase) are resistant to penicillins and also cephalosporins such as cefotaxime and ceftriaxone
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