SIADH, also known as syndrome of inappropriate antidiuretic hormone secretion, is frequently observed in individuals diagnosed with small cell lung cancer. The condition can also be caused by malignancy, pulmonary disorders, and certain medications.

Further Reading:

Syndrome of inappropriate antidiuretic hormone (SIADH) is a condition characterized by low sodium levels in the blood due to excessive secretion of antidiuretic hormone (ADH). ADH, also known as arginine vasopressin (AVP), is responsible for promoting water and sodium reabsorption in the body. SIADH occurs when there is impaired free water excretion, leading to euvolemic (normal fluid volume) hypotonic hyponatremia.

There are various causes of SIADH, including malignancies such as small cell lung cancer, stomach cancer, and prostate cancer, as well as neurological conditions like stroke, subarachnoid hemorrhage, and meningitis. Infections such as tuberculosis and pneumonia, as well as certain medications like thiazide diuretics and selective serotonin reuptake inhibitors (SSRIs), can also contribute to SIADH.

The diagnostic features of SIADH include low plasma osmolality, inappropriately elevated urine osmolality, urinary sodium levels above 30 mmol/L, and euvolemic. Symptoms of hyponatremia, which is a common consequence of SIADH, include nausea, vomiting, headache, confusion, lethargy, muscle weakness, seizures, and coma.

Management of SIADH involves correcting hyponatremia slowly to avoid complications such as central pontine myelinolysis. The underlying cause of SIADH should be treated if possible, such as discontinuing causative medications. Fluid restriction is typically recommended, with a daily limit of around 1000 ml for adults. In severe cases with neurological symptoms, intravenous hypertonic saline may be used. Medications like demeclocycline, which blocks ADH receptors, or ADH receptor antagonists like tolvaptan may also be considered.

It is important to monitor serum sodium levels closely during treatment, especially if using hypertonic saline, to prevent rapid correction that can lead to central pontine myelinolysis. Osmolality abnormalities can help determine the underlying cause of hyponatremia, with increased urine osmolality indicating dehydration or renal disease, and decreased urine osmolality suggesting SIADH or overhydration.

Pick’s disease is a rare neurodegenerative disorder that leads to a gradual decline in cognitive function known as frontotemporal dementia. One of the key features of this condition is the accumulation of tau proteins in neurons, forming silver-staining, spherical aggregations called ‘Pick bodies.’

Typically, Pick’s disease manifests between the ages of 40 and 60. Initially, individuals may experience changes in their personality, such as disinhibition, tactlessness, and vulgarity. They may also exhibit alterations in their moral values and attempt to distance themselves from their family. Difficulties with concentration, increased activity levels, pacing, and wandering are also common during this stage.

What sets Pick’s disease apart from Alzheimer’s disease is that the changes in personality occur before memory loss becomes apparent. As the disease progresses, patients will experience deficits in intellect, memory, and language.

Activated charcoal is a commonly used substance for decontamination in cases of poisoning. Its main function is to adsorb the molecules of the ingested toxin onto its surface.

Activated charcoal is a chemically inert form of carbon. It is a fine black powder that has no odor or taste. It is produced by subjecting carbonaceous matter to high temperatures, a process known as pyrolysis, and then concentrating it with a zinc chloride solution. This creates a network of pores within the charcoal, giving it a large absorptive area of approximately 3,000 m2/g. This porous structure helps prevent the absorption of the harmful toxin by up to 50%.

The usual dosage of activated charcoal is 50 grams for adults and 1 gram per kilogram of body weight for children. It can be administered orally or through a nasogastric tube. It is important to give the charcoal within one hour of ingestion, and it may be repeated after one hour if necessary.

However, there are certain situations where activated charcoal should not be used. If the patient is unconscious or in a coma, there is a risk of aspiration, so the charcoal should not be given. Similarly, if seizures are likely to occur, there is a risk of aspiration and the charcoal should be avoided. Additionally, if there is reduced gastrointestinal motility, there is a risk of obstruction, so activated charcoal should not be used in such cases.

Activated charcoal is effective in treating overdose with various drugs and toxins, including aspirin, paracetamol, barbiturates, tricyclic antidepressants, digoxin, amphetamines, morphine, cocaine, and phenothiazines. However, it is ineffective in treating overdose with substances such as iron, lithium, boric acid, cyanide, ethanol, ethylene glycol, methanol, malathion, DDT, carbamate, hydrocarbon, strong acids, or alkalis.

There are some potential adverse effects associated with activated charcoal. These include nausea and vomiting, diarrhea, constipation, bezoar formation (a mass of undigested material that can cause blockages), bowel obstruction, pulmonary aspiration (inhaling the charcoal into the lungs), and impaired absorption of oral medications or antidotes.

A threatened miscarriage happens when there is bleeding during the first trimester of pregnancy, but no fetal tissue has been expelled, and the opening of the cervix is closed.

If cervical dilatation occurs, a threatened miscarriage can progress to become an inevitable miscarriage. In this case, the pain and bleeding are usually more intense, and upon examination, the cervix will be found to be open.

The superior orbital fissure is a gap in the back wall of the orbit, created by the space between the greater and lesser wings of the sphenoid bone. Several structures pass through it to enter the orbit, starting from the top and going downwards. These include the lacrimal nerve (a branch of CN V1), the frontal nerve (another branch of CN V1), the superior ophthalmic vein, the trochlear nerve (CN IV), the superior division of the oculomotor nerve (CN III), the nasociliary nerve (a branch of CN V1), the inferior division of the oculomotor nerve (CN III), the abducens nerve (CN VI), and the inferior ophthalmic vein.

Adjacent to the superior orbital fissure, on the back wall of the orbit and towards the middle, is the optic canal. The optic nerve (CN II) exits the orbit through this canal, along with the ophthalmic artery.

Superior orbital fissure syndrome (SOFS) is a condition characterized by a combination of symptoms and signs that occur when cranial nerves III, IV, V1, and VI are compressed or injured as they pass through the superior orbital fissure. This condition also leads to swelling and protrusion of the eye due to impaired drainage and congestion. The main causes of SOFS are trauma, tumors, and inflammation. It is important to note that CN II is not affected by this syndrome, as it follows a separate path through the optic canal.

Pemphigus, derived from the Greek word for bubble ‘pemphix’, refers to a group of autoimmune disorders that cause blistering of the skin and/or mucosal surfaces. The most common subset is pemphigus vulgaris (PV), which accounts for approximately 70% of cases worldwide. PV is characterized by an autoimmune response where autoantibodies target cell surface antigens on keratinocytes, specifically desmogleins 1 and 3. This leads to a loss of cell-to-cell adhesion and separation, resulting in blister formation.

On the other hand, bullous pemphigoid (BP) is a chronic autoimmune blistering skin disorder that affects the subepidermal layer. It occurs when the basement membrane of the epidermis is attacked by IgG and sometimes IgE immunoglobulins, as well as activated T lymphocytes. The binding of autoantibodies to proteins and the release of cytokines from T cells trigger complement activation, neutrophil recruitment, and the release of proteolytic enzymes. These enzymes destroy the hemidesmosomes, leading to the formation of subepidermal blisters.

To summarize the differences between pemphigus vulgaris and bullous pemphigoid, the following provides a comparison:

Pemphigus Vulgaris:
– Age: Middle-aged people (mean age 50)
– Oral involvement: Common
– Blister type: Large, flaccid, and painful
– Blister content: Fluid-filled, often haemorrhagic
– Areas commonly affected: Initially face and scalp, then spread to the chest and back
– Nikolsky sign: Usually positive
– Pruritus: Rare
– Skin biopsy: Intra-epidermal deposition of IgG between cells throughout the epidermis

Bullous Pemphigoid:
– Age: Elderly people (mean age 80)
– Oral involvement: Rare
– Blister type: Large and tense
– Blister content: Fluid-filled
– Areas commonly affected: Upper arms, thighs, and skin flexures
– Nikolsky sign: Usually negative
– Pruritus: Common
– Skin biopsy: A band of IgG and/or C3 at the dermo-epidermal junction

Cardiac enzymes do not increase in unstable angina. However, if cardiac markers do rise, it is classified as a non-ST elevation myocardial infarction (NSTEMI). Both unstable angina and NSTEMI can have a normal ECG. An extended ventricular activation time indicates damage to the heart muscle. This occurs because infarcting myocardium conducts electrical impulses at a slower pace, resulting in a prolonged interval between the start of the QRS complex and the apex of the R wave. A positive troponin test indicates the presence of necrosis in cardiac myocytes.

Summary:
Marker | Initial Rise | Peak | Normal at
Creatine kinase | 4-8 hours | 18 hours 2-3 days | CK-MB = main cardiac isoenzyme
Myoglobin | 1-4 hours | 6-7 hours | 24 hours | Low specificity due to skeletal muscle damage
Troponin I | 3-12 hours | 24 hours | 3-10 days | Appears to be the most sensitive and specific
HFABP | 1-2 hours | 5-10 hours | 24 hours | HFABP = heart fatty acid binding protein
LDH | 10 hours | 24-48 hours | 14 days | Cardiac muscle mainly contains LDH

A pleural effusion refers to the accumulation of excess fluid in the pleural cavity, which is the fluid-filled space between the parietal and visceral pleura. Normally, this cavity contains about 5-10 ml of lubricating fluid that allows the pleurae to slide over each other and helps the lungs fill with air as the thorax expands. However, when there is too much fluid in the pleural cavity, it hinders breathing by limiting lung expansion.

Percutaneous pleural aspiration is commonly performed for two main reasons: to investigate pleural effusion and to provide relief from breathlessness caused by pleural effusion. According to the guidelines from the British Thoracic Society (BTS), pleural aspiration should be reserved for the investigation of unilateral exudative pleural effusions. It should not be done if unilateral or bilateral transudative effusion is suspected, unless there are atypical features or a lack of response to therapy. In urgent cases where respiratory distress is caused by pleural effusion, pleural aspiration can also be used to quickly decompress the pleural space.

During the procedure, the patient is typically seated upright with a pillow supporting their arms and head. It is important for the patient not to lean too far forward, as this increases the risk of injury to the liver and spleen. The conventional site for aspiration is in the mid-scapular line at the back (approximately 10 cm to the side of the spine), one or two spaces below the upper level of the fluid. To avoid damaging the intercostal nerves and vessels that run just below the rib, the needle should be inserted just above the upper border of the chosen rib.

A recent audit conducted by the Royal College of Emergency Medicine (RCEM) in 2018 revealed a concerning decline in the standards of pain management for children with fractured limbs in Emergency Departments (EDs). The audit found that the majority of patients experienced longer waiting times for pain relief compared to previous years. Shockingly, more than 1 in 10 children who presented with significant pain due to a limb fracture did not receive any pain relief at all.

To address this issue, the Agency for Health Care Policy and Research (AHCPR) in the USA recommends following the ABCs of pain management for all patients, including children. This approach involves regularly asking about pain, systematically assessing it, believing the patient and their family in their reports of pain and what relieves it, choosing appropriate pain control options, delivering interventions in a timely and coordinated manner, and empowering patients and their families to have control over their pain management.

The RCEM has established standards that require a child’s pain to be assessed within 15 minutes of their arrival at the ED. This is considered a fundamental standard. Various rating scales are available for assessing pain in children, with the choice depending on the child’s age and ability to use the scale. These scales include the Wong-Baker Faces Pain Rating Scale, Numeric rating scale, and Behavioural scale.

To ensure timely administration of analgesia to children in acute pain, the RCEM has set specific standards. These standards state that 100% of patients in severe pain should receive appropriate analgesia within 60 minutes of their arrival or triage, whichever comes first. Additionally, 75% should receive analgesia within 30 minutes, and 50% within 20 minutes.

According to the 2011 recommendations from the World Health Organization (WHO), HbA1c can now be used as a diagnostic test for diabetes. However, this is only applicable if stringent quality assurance tests are in place and the assays are standardized to criteria aligned with international reference values. Additionally, accurate measurement of HbA1c is only possible if there are no conditions present that could hinder its accuracy.

To diagnose diabetes using HbA1c, a value of 48 mmol/mol (6.5%) is recommended as the cut-off point. It’s important to note that a value lower than 48 mmol/mol (6.5%) does not exclude the possibility of diabetes, as glucose tests are still necessary for a definitive diagnosis.

When using glucose tests, the following criteria are considered diagnostic for diabetes mellitus:
– A random venous plasma glucose concentration greater than 11.1 mmol/l
– A fasting plasma glucose concentration greater than 7.0 mmol/l
– A two-hour plasma glucose concentration greater than 11.1 mmol/l, two hours after consuming 75g of anhydrous glucose in an oral glucose tolerance test (OGTT)

However, there are certain circumstances where HbA1c is not appropriate for diagnosing diabetes mellitus. These include:
– ALL children and young people
– Patients of any age suspected of having Type 1 diabetes
– Patients with symptoms of diabetes for less than two months
– Patients at high risk of diabetes who are acutely ill, such as those requiring hospital admission
– Patients taking medication that may cause a rapid rise in glucose levels, such as steroids or antipsychotics
– Patients with acute pancreatic damage, including those who have undergone pancreatic surgery
– Pregnant individuals
– Presence of genetic, hematologic, and illness-related factors that can influence HbA1c and its measurement.