Homonymous quadrantanopias occur when there are lesions in the optic radiation. The optic tract passes through the posterolateral angle of the optic chiasm, running alongside the cerebral peduncle and inside the uncus of the temporal lobe. Eventually, it reaches the lateral geniculate body (LGN) in the thalamus. Acting as a relay center, the LGN sends axons through the optic radiation to the primary visual cortex in the occipital lobe. The upper optic radiation carries fibers from the superior retinal quadrants (which corresponds to the lower half of the visual field) and travels through the parietal lobe. On the other hand, the lower optic radiation carries fibers from the inferior retinal quadrants (which corresponds to the upper half of the visual field) and travels through the temporal lobe. Consequently, lesions in the temporal lobe can lead to superior homonymous quadrantanopias, while lesions in the parietal lobe can cause inferior homonymous quadrantanopias. The diagram below provides a summary of the different visual field defects resulting from lesions at various points in the visual pathway.

This patient has presented with an Addisonian crisis, which is a rare but potentially catastrophic condition if not diagnosed promptly. The most likely underlying rheumatological diagnosis in this case is polymyalgia rheumatica, and it is likely that the GP started the patient on prednisolone medication.

Addison’s disease occurs when the adrenal glands underproduce steroid hormones, affecting the production of glucocorticoids, mineralocorticoids, and sex steroids. The main causes of Addison’s disease include autoimmune adrenalitis (accounting for 80% of cases), bilateral adrenalectomy, Waterhouse-Friderichsen syndrome (hemorrhage into the adrenal glands), and tuberculosis.

An Addisonian crisis is most commonly triggered by the deliberate or accidental withdrawal of steroid therapy in patients with Addison’s disease. Other factors that can precipitate a crisis include infection, trauma, myocardial infarction, cerebral infarction, asthma, hypothermia, and alcohol abuse.

The clinical features of Addison’s disease include weakness, lethargy, hypotension (especially orthostatic hypotension), nausea, vomiting, weight loss, reduced axillary and pubic hair, depression, and hyperpigmentation (particularly in palmar creases, buccal mucosa, and exposed areas). In an Addisonian crisis, the main features are usually hypoglycemia and shock, characterized by tachycardia, peripheral vasoconstriction, hypotension, altered consciousness, and coma.

Biochemically, Addison’s disease is characterized by increased ACTH levels (as a compensatory response to stimulate the adrenal glands), elevated serum renin levels, hyponatremia, hyperkalemia, hypercalcemia, hypoglycemia, and metabolic acidosis. Diagnostic investigations may include the Synacthen test, plasma ACTH level, plasma renin level, and adrenocortical antibodies.

Management of Addison’s disease should be overseen by an Endocrinologist. Typically, patients require hydrocortisone, fludrocortisone, and dehydroepiandrosterone. Some patients may also need thyroxine if there is hypothalamic-pituitary disease present. Treatment is lifelong, and patients should carry a steroid card and a MedicAlert bracelet, being aware of the possibility of an Addisonian crisis.

When starting treatment with strong opioids for pain relief in palliative care, it is recommended to offer patients regular oral sustained-release or oral immediate-release morphine, depending on their preference. In addition, provide rescue doses of oral immediate-release morphine for breakthrough pain. For patients without renal or hepatic comorbidities, a typical total daily starting dose schedule of 20-30 mg of oral morphine is suggested, along with 5 mg of oral immediate-release morphine for rescue doses during the titration phase. It is important to adjust the dose until a good balance is achieved between pain control and side effects. If this balance is not reached after a few dose adjustments, it is advisable to seek specialist advice. Patients should be reviewed frequently, especially during the titration phase. For patients with moderate to severe renal or hepatic impairment, it is recommended to consult a specialist before prescribing strong opioids.

For maintenance therapy, oral sustained-release morphine is recommended as the first-line treatment for patients with advanced and progressive disease who require strong opioids. Transdermal patch formulations should not be routinely offered as first-line maintenance treatment unless oral opioids are not suitable. If pain remains inadequately controlled despite optimizing first-line maintenance treatment, it is important to review the analgesic strategy and consider seeking specialist advice.

When it comes to breakthrough pain, oral immediate-release morphine should be offered as the first-line rescue medication for patients on maintenance oral morphine treatment. Fast-acting fentanyl should not be offered as the first-line rescue medication. If pain continues to be inadequately controlled despite optimizing treatment, it may be necessary to seek specialist advice.

In cases where oral opioids are not suitable and analgesic requirements are stable, transdermal patches with the lowest acquisition cost can be considered. However, it is important to consult a specialist for guidance if needed. Similarly, for patients in whom oral opioids are not suitable and analgesic requirements are unstable, subcutaneous opioids with the lowest acquisition cost can be considered, with specialist advice if necessary.

For more information, please refer to the NICE Clinical Knowledge Summary: Opioids for pain relief in palliative care. https://www.nice.org.uk/guidance/cg140

Discitis is an infection that affects the space between the intervertebral discs in the spine. This condition can have serious consequences, including the formation of abscesses and sepsis. The most common cause of discitis is usually Staphylococcus aureus, but other organisms like Streptococcus viridans and Pseudomonas aeruginosa may be responsible in intravenous drug users and those with weakened immune systems. Gram-negative organisms such as Escherichia coli and Mycobacterium tuberculosis can also cause discitis.

There are several risk factors that increase the likelihood of developing discitis. These include having undergone spinal surgery (which occurs in 1-2% of cases post-operatively), having an immunodeficiency, being an intravenous drug user, being under the age of eight, having diabetes mellitus, or having a malignancy.

The typical symptoms of discitis include back or neck pain (which occurs in over 90% of cases), pain that often wakes the patient from sleep, fever (present in 60-70% of cases), and neurological deficits (which can occur in up to 50% of cases). In children, refusal to walk may also be a symptom.

When diagnosing discitis, MRI is the preferred imaging modality due to its high sensitivity and specificity. It is important to image the entire spine, as discitis often affects multiple levels. Plain radiographs are not very sensitive to the early changes of discitis and may appear normal for 2-4 weeks. CT scanning is also not very sensitive in detecting discitis.

Treatment for discitis involves admission to the hospital for intravenous antibiotics. Before starting the antibiotics, it is important to send three sets of blood cultures and a full set of blood tests, including a CRP, to the lab. The choice of antibiotics depends on the specific situation. A typical antibiotic regimen for discitis may include IV flucloxacillin as the first-line treatment if there is no penicillin allergy, IV vancomycin if the infection was acquired in the hospital or there is a high risk of MRSA, and possibly IV gentamicin if there is a possibility of a Gram-negative infection. In cases where there is acute kidney injury and Gram-negative cover is required, IV piperacillin-tazobactam alone may be used.

Activated charcoal is a useful treatment for many drug poisonings, but it is not effective against certain types of poisonings. To remember these exceptions, you can use the mnemonic PHAILS. This stands for Pesticides (specifically organophosphates), Hydrocarbons, Acids (strong), alkalis (strong), alcohols (such as ethanol, methanol, and ethylene glycol), Iron, Lithium, and Solvents.

Further Reading:

Poisoning in the emergency department is often caused by accidental or intentional overdose of prescribed drugs. Supportive treatment is the primary approach for managing most poisonings. This includes ensuring a clear airway, proper ventilation, maintaining normal fluid levels, temperature, and blood sugar levels, correcting any abnormal blood chemistry, controlling seizures, and assessing and treating any injuries.

In addition to supportive treatment, clinicians may need to consider strategies for decontamination, elimination, and administration of antidotes. Decontamination involves removing poisons from the skin or gastrointestinal tract. This can be done through rinsing the skin or using methods such as activated charcoal, gastric lavage, induced emesis, or whole bowel irrigation. However, induced emesis is no longer commonly used, while gastric lavage and whole bowel irrigation are rarely used.

Elimination methods include urinary alkalinization, hemodialysis, and hemoperfusion. These techniques help remove toxins from the body.

Activated charcoal is a commonly used method for decontamination. It works by binding toxins in the gastrointestinal tract, preventing their absorption. It is most effective if given within one hour of ingestion. However, it is contraindicated in patients with an insecure airway due to the risk of aspiration. Activated charcoal can be used for many drugs, but it is ineffective for certain poisonings, including pesticides (organophosphates), hydrocarbons, strong acids and alkalis, alcohols (ethanol, methanol, ethylene glycol), iron, lithium, and solvents.

Antidotes are specific treatments for poisoning caused by certain drugs or toxins. For example, cyanide poisoning can be treated with dicobalt edetate, hydroxocobalamin, or sodium nitrite and sodium thiosulphate. Benzodiazepine poisoning can be treated with flumazanil, while opiate poisoning can be treated with naloxone. Other examples include protamine for heparin poisoning, vitamin K or fresh frozen plasma for warfarin poisoning, fomepizole or ethanol for methanol poisoning, and methylene blue for methemoglobinemia caused by benzocaine or nitrates.

There are many other antidotes available for different types of poisoning, and resources such as TOXBASE and the National Poisons Information Service (NPIS) can provide valuable advice on managing poisonings.

This presentation strongly suggests a diagnosis of whooping cough, which is an infection of the upper respiratory tract caused by the bacteria Bordetella pertussis. The disease is highly contagious and is transmitted through respiratory droplets. The incubation period is typically 7-21 days, and it is estimated that about 90% of close household contacts will become infected.

The clinical course of whooping cough can be divided into two stages. The first stage, known as the catarrhal stage, is similar to a mild respiratory infection with symptoms such as low-grade fever and a runny nose. A cough may be present, but it is usually not as severe as in the second stage. This phase typically lasts about a week.

The second stage, called the paroxysmal stage, is characterized by the development of a distinctive cough. The coughing occurs in spasms, often preceded by an inspiratory whoop sound. These spasms are followed by a series of rapid, hacking coughs. Patients may also experience vomiting and develop subconjunctival hemorrhages and petechiae. Between spasms, patients generally feel well and there are usually no abnormal chest findings. This stage can last up to 3 months, with a gradual recovery over this period. The later stages of this phase are sometimes referred to as the convalescent stage.

Complications of whooping cough can include secondary pneumonia, rib fractures, pneumothorax, hernias, syncopal episodes, encephalopathy, and seizures.

Public Health England (PHE) has specific recommendations for testing for whooping cough based on the age of the patient, the time since onset of illness, and the severity of the presentation.

For infants under 12 months of age, hospitalized patients should be tested using PCR testing. Non-hospitalized patients within two weeks of onset should be investigated with culture of a nasopharyngeal swab or aspirate. Non-hospitalized patients presenting over two weeks after onset should be tested using serology for anti-pertussis toxin IgG antibody levels.

For children over 12 months of age and adults, patients within two weeks of onset should be tested using culture of a nasopharyngeal swab or aspirate. Patients aged 5 to 16 who have not received the vaccine within the last year and present over two weeks after onset should have oral fluid testing for anti-pertussis toxin IgG antibody levels.

A non-blanching rash in a child should always raise suspicion of meningococcal septicaemia, especially if the child appears unwell, has purpura lesions larger than 2 mm in diameter, a capillary refill time of more than 3 seconds, or neck stiffness. In the UK, most cases of meningococcal septicaemia are caused by Neisseria meningitidis group B.

In this particular case, the child is clearly very sick and showing signs of septic shock. It is crucial to administer a single dose of benzylpenicillin without delay and arrange for immediate transfer to the nearest Emergency Department via ambulance.

The recommended doses of benzylpenicillin based on age are as follows:
– Infants under 1 year of age: 300 mg of IM or IV benzylpenicillin
– Children aged 1 to 9 years: 600 mg of IM or IV benzylpenicillin
– Children and adults aged 10 years or older: 1.2 g of IM or IV benzylpenicillin.

Thiamine deficiency is frequently seen in individuals who are dependent on alcohol. This is primarily due to their inadequate diet, the presence of gastritis which affects thiamine absorption, and the fact that thiamine is involved in alcohol metabolism as a coenzyme. If left untreated, thiamine deficiency can lead to Wernicke’s encephalopathy, which can further progress to Korsakoff’s syndrome.

It is important to note that administering glucose-containing intravenous fluids without thiamine to a patient with chronic thiamine deficiency can trigger Wernicke’s encephalopathy. Therefore, individuals undergoing detoxification should receive parenteral high-potency B complex vitamins (Pabrinex) as a preventive treatment. However, it is crucial to have resuscitation facilities available during administration due to the risk of anaphylaxis. The risk of anaphylaxis is lower when the drug is given intramuscularly (IM). A daily dose of one pair of ampoules of Pabrinex, containing 250 mg of thiamine, should be administered IM or intravenously (IV) for a period of three to five days.

Once the 3-5 day course of Pabrinex is completed, the patient should transition to oral vitamin B Compound-strong and oral thiamine tablets for continued treatment.

For more information, please refer to the NICE pathway for acute alcohol withdrawal.

Ectopic production of ACTH is linked to small-cell lung cancer and can lead to Cushing’s syndrome. It can also be observed in cases of pancreatic cancer and thymoma.

Hypertrophic pulmonary osteoarthropathy (HPOA) is characterized by the presence of periostitis, arthritis, and finger clubbing. On plain X-ray, subperiosteal new bone formation can be detected. This condition primarily affects the long bones and often causes pain. It is most commonly associated with squamous cell lung cancer and pulmonary adenocarcinoma.

Gynaecomastia, which is the enlargement of breast tissue in males, can occur as a result of squamous cell lung cancer. In these cases, it tends to be accompanied by pain.

Rarely, squamous cell lung cancer can cause ectopic production of TSH, leading to hyperthyroidism.

Carcinoid syndrome is a condition that arises from carcinoid tumors, which secrete serotonin and kallikreins. This syndrome manifests as episodes of flushing, diarrhea, and bronchospasm. Additionally, 50% of patients develop a secondary restrictive cardiomyopathy. Carcinoid tumors can occur in various locations, with the small intestine being the most common site. Other locations include the lungs (bronchial adenoma), rectum, appendix, and stomach.

Statins, although generally safe and well-tolerated, can cause myopathy and myotoxicity. This range of muscle-related side effects can vary from mild muscle pain to the most severe case of rhabdomyolysis, which can lead to kidney failure, blood clotting issues, and even death.

The different levels of myotoxicity associated with statins are as follows:
– Myalgia: muscle symptoms without an increase in creatine kinase (CK) levels.
– Asymptomatic myopathy: elevated CK levels without muscle symptoms.
– Myositis: muscle symptoms with CK levels elevated less than 10 times the upper limit of normal.
– Rhabdomyolysis: muscle symptoms with CK levels elevated more than 10 times the upper limit of normal, potentially leading to myoglobinuria (presence of myoglobin in urine) and renal failure.

Most statins are broken down by the cytochrome P450 enzyme system. When taken with drugs that strongly inhibit this system, the concentration of statins in the blood can significantly increase. This, in turn, raises the risk of myopathy. A well-known example of this is the combination of statins with macrolide antibiotics like erythromycin and clarithromycin. Co-prescribing these drugs with statins has been linked to a higher risk of myopathy, hospitalization due to rhabdomyolysis, acute kidney injury, and increased mortality rates.