One of the most important complications in patients with PKD is being affected by berry aneurysms that may burst, causing a subarachnoid haemorrhage, which seems to be the case in this patient.

High-resolution CT (HRCT) scanning is more sensitive than standard chest radiography and is highly specific for diagnosing emphysema (outlined bullae are not always visible on a radiograph).

HRCT scanning may provide an adjunct means of diagnosing various forms of COPD (i.e., lower lobe disease may suggest AAT deficiency) and may help the clinician to determine whether surgical intervention would benefit the patient.

Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.

Pathophysiology of methanol toxicity:
When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment.
Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa.
Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid.
Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.

Clinical presentation:
Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period.
Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis.
Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”

Treatment:
Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate.

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.

Before the initiation of trastuzumab, an echocardiography is a must to rule out any pre-existing cardiac abnormalities as trastuzumab is cardiotoxic.

Trastuzumab (Herceptin) is a monoclonal antibody directed against the HER2/neu receptor. It is used mainly in metastatic breast cancer although some patients with early disease are now also given trastuzumab.

Adverse effects include:
Flu-like symptoms and diarrhoea are common.
Cardiotoxicity:
– Risk increases when anthracyclines are used concomitantly.
– Trastuzumab-induced cardiac dysfunctions are regarded as less severe and largely reversible because primary cardiomyocyte do not show ultrastructure changes unlike those associated with anthracycline-induced cardiotoxicity.
– Primary myocyte injury does not occur in patients who were treated with trastuzumab.

Insulin is produced by the beta-cells in the islets of Langerhans in the pancreas while Glucagon is secreted from the alpha cells of the pancreatic islets of Langerhans.
Type 1 diabetes mellitus is the culmination of lymphocytic infiltration and destruction of the beta cells of the islets of Langerhans in the pancreas. As beta-cell mass declines, insulin secretion decreases until the available insulin is no longer adequate to maintain normal blood glucose levels. After 80-90% of the beta cells are destroyed, hyperglycaemia develops and diabetes may be diagnosed.

The given clinical scenario is highly suggestive of a borderline personality disorder.

Borderline personality disorder is marked out by instability in moods, behaviour, and relationships. The diagnosis is confirmed by the presence of at least 5 of the following symptoms;
1) Extreme reactions including panic, depression, rage, or frantic actions to abandonment, whether real or perceived
2) A pattern of intense and stormy relationships with family, friends, and loved ones, often veering from extreme closeness and love to extreme dislike or anger
3) Distorted and unstable self-image or sense of self, which can result in sudden changes in feelings, opinions, values, or plans and goals for the future (such as school or career choices)
4) Impulsive and often dangerous behaviours, such as spending sprees, unsafe sex, substance abuse, reckless driving, and binge eating
5) Recurring suicidal behaviours or threats or self-harming behaviour, such as cutting, intense and highly changeable moods, with each episode lasting from a few hours to a few days
6) Chronic feelings of emptiness and/or boredom
7) Inappropriate, intense anger or problems controlling anger
8) Having stress-related paranoid thoughts or severe dissociative symptoms, such as feeling cut off from oneself, observing oneself from outside the body, or losing touch with reality.

Other options:
There are no features consistent with endogenous depression, such as early morning wakening or loss of appetite.
There are also no features consistent with hypomania such as pressure of speech, a flight of ideas, or over-exuberant behaviour.
The lack of history of drug abuse rules out drug-induced psychosis.
An anti-social personality disorder is characterized by a failure to conform to social norms and repeated lawbreaking. There is consistent irresponsibility, impulsivity, and disregard for both their safety and that of others. This is not the case in the given scenario.

The patient is presenting with symptoms of lateral medullary syndrome also known as Wallenberg’s syndrome or posterior inferior cerebellar artery syndrome, where the symptoms are due to an ischemia in the brainstem. The classical symptoms include contralateral sensory deficits of the trunk region paired with ipsilateral facial sensory deficits.

This patient’s symptoms of anaemia, leukopenia, and elevated non-albumin protein concentration with fatigue and weight loss, point to myeloma. Thus plasma protein electrophoresis or Serum Protein Electrophoresis (SPE) is indicated when there is suspicion of myeloma.

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.

The patient is asymptomatic but matches the diagnostic criteria for multiple myeloma (MM). Therefore, the underlying diagnosis of this condition is smouldering multiple myeloma (SMM). SMM is an early precursor to MM. Its treatment is typically to watch and wait.

MM is a neoplasm of the bone marrow plasma cells. Peak incidence is in patients aged 60–70 years.

Clinical features of MM include:
1. Ostealgia, osteoporosis, pathological fractures (typically vertebral), and osteolytic lesions
2. Lethargy
3. Infections
4. Hypercalcaemia
5. Renal failure
6. Other features: amyloidosis e.g. macroglossia, carpal tunnel syndrome; neuropathy; hyperviscosity

Diagnosis of MM is based on the confirmation of (a) one major criterion and one minor criterion or (b) three minor criteria in an individual who has signs or symptoms of multiple myeloma.

Major criteria:
1. >30% plasma cells on bone marrow biopsy
2. Monoclonal band of paraprotein on electrophoresis: >35g/L for IgG, 20g/L for IgA, or >1g of light chains excreted in the urine per day

Minor criteria:
1. 10–30% plasma cells on bone marrow biopsy
2. Abnormal monoclonal band but levels less than listed above
3. Lytic bone lesions observed radiographically
4. Immunosuppression

First and foremost, the patient should be put on ECG monitoring to identify the cardiac state, and because of the markedly raised serum potassium, a calcium gluconate bolus will have the immediate effect of moderating the nerve and muscle performance.

The patient has bloody diarrhoea that sounds like a food poisoning in the clinical scenario. Campylobacter is the most common cause of this in the United Kingdom. This is then followed by Salmonella and Shigella. The symptoms are usually self limiting. This is more likely to be bacterial from the food than a viral gastroenteritis.

Dopamine (DA) holds a predominant role in the regulation of prolactin (PRL) secretion. Through a direct effect on anterior pituitary lactotrophs, DA inhibits the basally high-secretory tone of the cell. It accomplishes this by binding to D2 receptors expressed on the cell membrane of the lactotroph, activation of which results in a reduction of PRL exocytosis and gene expression by a variety of intracellular signalling mechanisms.

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.

Herpes zoster oticus is a viral infection of the inner, middle, and external ear. It manifests as severe otalgia with associated cutaneous vesicular eruption, usually of the external canal and pinna. When associated with facial paralysis, the infection is called Ramsay Hunt syndrome.

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

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.

The clinical picture points to Lambert– Eaton myasthenic syndrome (LEMS) which often presents with weakness of the arms and legs. In LEMS, antibodies against voltage-gated calcium channels (VGCC) decrease the amount of calcium that can enter the nerve ending, causing autonomic symptoms like dry mouth and slurring of speech, as seen in this patient.

Because the medical history included tonsillitis followed by haematuria and hypertension, there is a strong suspicion of a case of post-streptococcal glomerulonephritis (PSGN). Patients with PSGN usually have serological findings showing depressed serum haemolytic component CH50 and serum concentrations of C3. Sometimes depressed C4 levels are also apparent, but not always, therefore, the answer to this question is: depressed CH50 level.