Clozapine can cause neutropenia or agranulocytosis.

Clozapine is an atypical antipsychotic used in the treatment of schizophrenia, and in patients who are intolerant to, or unresponsive to other antipsychotics.

It is a weak D2-receptor and D1-receptor blocking activity, with noradrenolytic, anticholinergic, and antihistaminic properties.

Many antipsychotic drugs can occasionally cause bone marrow depression, but agranulocytosis is particularly associated with clozapine.

Other side effects include:
Hypotension, tachycardia
Fever, sedation, seizures (with high doses)
Appetite increase
Constipation
Heartburn
Weight gain
Extrapyramidal symptoms
Agranulocytosis
Neuroleptic malignant syndrome

Lead poisoning is characterised by abdominal pain, fatigue, constipation, peripheral neuropathy (mainly motor), and blue lines on gum margin in 20% of the adult patients (very rare in children).

For diagnosis, the level of lead in blood is usually considered with levels greater than 10 mcg/dL being significant. Furthermore, the blood film shows microcytic anaemia and basophilic stippling of red blood cells. Urinary coproporphyrin is increased (urinary porphobilinogen and uroporphyrin levels are normal to slightly increased). Raised serum and urine levels of delta-aminolaevulinic acid may also be seen, making it sometimes difficult to differentiate from acute intermittent porphyria.

Charles Bonnet syndrome (CBS) involves visual hallucinations due to eye disease, usually associated with a sharp decline in vision. The phenomenon is seen in patients with moderate or severe visual impairment. It can occur spontaneously as the vision declines or it may be precipitated, in predisposed individuals, by concurrent illness such as infections elsewhere in the body.

It is not clear why CBS develops or why some individuals appear to be predisposed to it. It is particularly noted in patients with advanced macular degeneration. It has been suggested that reduced or absent stimulation of the visual system leads to increased excitability of the visual cortex (deafferentation hypothesis). This release phenomenon is compared to phantom limb symptoms after amputation.

CBS is much more common in older patients because conditions causing marked visual loss are more common in older people. However, it can occur at any age and has been described in children.
The prevalence is hard to assess due to considerable under-reporting, perhaps because patients frequently fear that it is a sign of mental illness or dementia. However, it is thought to occur in:
About 10-15% of patients with moderate visual loss.
Possibly up to 50% of people with severe visual loss.
Presentation:
The nature of the hallucination depends on the part of the brain that is activated. The hallucinations may be black and white or in colour. They may involve grids/brickwork/lattice patterns but are typically much more complex:

The hallucinations are always outside the body.
The hallucinations are purely visual – other senses are not involved.
The hallucinations have no personal meaning to the patient.
Hallucinations may last seconds, minutes or hours.
CBS tends to occur in a ‘state of quiet restfulness’. This may be after a meal or when listening to the radio (but not when dozing off).
Symptoms also have a tendency to occur in dim lighting conditions.
Patients may report high levels of distress, with some patients reporting anger, anxiety and even fear associated with the hallucinations.

Glomerulosclerosis is the scarring and hardening of the glomeruli known as diabetic glomerulosclerosis occurring in long-standing diabetes.

Scabies is due to an infestation of Sarcoptes scabiei and most commonly presents with these symptoms. The organism resides in burrows in a pattern specifically affecting the interdigital spaces and the skin folds of the arms and legs. The infection spreads from one person to another, especially in populated communities, through close contact.
Henoch-Schönlein purpura is a type of vascular inflammation.
Psoriasis rash is characterised by scaly plaques affecting the extensor surfaces of the body. Pemphigus vulgaris and bullous pemphigoid both are bullous disorders of the skin. They may present as crusted, weeping, diffuse lesions and there may be involvement in other sites; erosions in the mouth are typically involved in pemphigus vulgaris. Bullous pemphigoid involves the flexural areas and may be associated with a new medication.

A Mongolian spot can be present in new born babies which usually appears over the back and fades with time. There is nothing to worry about.

Felty syndrome is a severe subtype of seropositive Rheumatoid arthritis. Clinical triad consists of arthritis, splenomegaly, and neutropenia (leads to an increased risk of recurrent bacterial infections). Other symptoms include skin ulcers of the lower limbs (indicating vasculitis), hepatomegaly, fever, and chest pain (indicating pleuritis or pericarditis). It is associated with increased risk of developing non-Hodgkin lymphoma.

Klinefelter syndrome (KS), the most common human sex chromosome disorder 47,XXY. It is characterized by hypogonadism (micro-orchidism, oligospermia/azoospermia) and gynecomastia in late puberty. If Klinefelter syndrome is not diagnosed prenatally, a patient with 47,XXY karyotype may demonstrate various subtle, age-related clinical signs that would prompt diagnostic testing. These include the following:
Infants: Hypospadias, small phallus, cryptorchidism.
Toddlers: Developmental delay (especially expressive language skills), hypotonia.
Older boys and adolescent males: Tall stature; delayed or incomplete pubertal development with eunuchoid body habitus; gynecomastia; small, firm testes; sparse body hair.

From childhood with progression to early puberty, the pituitary-gonadal function observed is within normal limits for 47,XXY males.
At mid puberty and later, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) concentrations rise to hyper-gonadotropic levels, inhibin B levels fall until they are undetectable, and testosterone levels are at low or low-normal levels after an initial increase.

Fragile X syndrome, also termed Martin-Bell syndrome or marker X syndrome, is the most common cause of inherited mental retardation, intellectual disability, and autism.
However, the patient here does not have any mental disabilities as he already works as a clerk, and that too would make Down’s Syndrome less likely.

Classic Kallmann syndrome (KS) and idiopathic hypogonadotropic hypogonadism (IHH) are rare genetic conditions that encompass the spectrum of isolated hypogonadotropic hypogonadism. Most patients have gonadotropin-releasing hormone (GnRH) deficiency, as suggested by their response to pulsatile GnRH therapy. Hypothalamic-pituitary function is otherwise normal in most patients, and hypothalamic-pituitary imaging reveals no space-occupying lesions. By definition, either anosmia or severe hyposmia is present in patients with Kallmann syndrome, in contrast to patients with idiopathic hypogonadotropic hypogonadism, whose sense of smell is normal.

The dose is calculated, using the conversion factor, as follows:

(Conversion factor used to convert oral morphine to subcutaneous diamorphine = Divide the total daily dose of oral morphine by 3)
Hence,
60mg*2 = 120mg
120mg/3 = 40mg

The side effects of opioids can be transient or persistent, and these include constipation, nausea, and drowsiness. Therefore, all patients taking opioids should also be prescribed a laxative and an anti-emetic (if the nausea is persistent). Dose-adjustment may be necessary in cases of persistent drowsiness. Moreover, strong opioids can also provide quick relief from metastatic bone pain, as compared to NSAIDs, bisphosphonates, and radiotherapy.

Absolute contraindications for fibrinolytic use in STEMI

Prior intracranial haemorrhage (ICH)
Known structural cerebral vascular lesion
Known malignant intracranial neoplasm
Ischemic stroke within 3 months
Suspected aortic dissection
Active bleeding or bleeding diathesis (excluding menses)
Significant closed head trauma or facial trauma within 3 months
Intracranial or intraspinal surgery within 2 months
Severe uncontrolled hypertension (unresponsive to emergency therapy)
For streptokinase, prior treatment within the previous 6 months

Left ventricular ejection fraction = (stroke volume / end diastolic LV volume ) * 100%

Stroke volume = end diastolic LV volume – end systolic LV volume

Pulse pressure = Systolic Pressure – Diastolic Pressure

The cardiovascular effects of β-adrenoceptor block result from reduction of the sympathetic drive which includes reduced heart rate (automaticity) and reduced myocardial contractility (rate of rise of pressure in the ventricle). This will lead to reduced cardiac output and an overall fall in oxygen consumption.

Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers. Other STDs including HIV, syphilis have different presentations. Psoriatic arthritis is not commonly associated with urethritis and conjunctivitis.

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.

Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases, as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.

Use of Hyperbaric oxygen therapy (HBOT) for treatment of mild to moderate CO poisoning is not routine.
The selection criteria for HBOT in cases of CO poisoning include:
• COHb levels > 20-25%
• COHb levels > 20% in pregnant patient
• Loss of consciousness
• Severe metabolic acidosis (pH <7.1)
• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
Principle of HBOT:
Exposing patients to 100 percent oxygen under supra-atmospheric conditions results in a decrease in the half-life (t1/2) of COHb, from , 90 min in atmospheric air to , 30 minutes. The amount of oxygen dissolved in the blood also rises from , 0.3 to 6 mL/dL, increasing the delivery of non-haemoglobin-bound oxygen to the tissues.

There is a strong suspicion of drug-induced acute tubulo-interstitial nephritis with the classic triad of symptoms of rash, joint pain and eosinophils in the blood, associated with non-specific symptoms of fever and fatigue. This can be confirmed with renal biopsy showing interstitial oedema with a heavy infiltrate of inflammatory cells and variable tubular necrosis.

Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.

The symptoms of ataxia, slurred speech and blurred vision are all suggestive of phenytoin toxicity. Cimetidine increases the efficacy of phenytoin by reducing its hepatic metabolism.

Phenytoin has a narrow therapeutic index (10-20 mg/L) and its levels are monitored by measuring the total phenytoin concentration.
Cimetidine is an H2 receptor antagonist used in the treatment of peptic ulcers. It acts by decreasing gastric acid secretion.
Cimetidine also has an inhibitory effect on several isoforms of the cytochrome enzyme system including the CYP450 enzymatic pathway. Phenytoin is metabolized by the same cytochrome P450 enzyme system in the liver.
Thus, the simultaneous administration of both these medications leads to an inhibition of phenytoin metabolism and thus increases its circulating levels leading to phenytoin toxicity.

Aprepitant is an anti-emetic which blocks the neurokinin 1 (NK1) receptor and acts as a substance P antagonist. It is licensed for chemotherapy-induced nausea and vomiting (CINV) and for prevention of postoperative nausea and vomiting.

Nausea and vomiting are the common side effects of chemotherapy. Risk factors for the development of these symptoms include age<50 years, anxiety, concurrent use of opioids, and the type of chemotherapy administered.

T. gondii infection in immunocompetent people is usually asymptomatic. It can present as fits in patients with AIDs, who are immunosuppressed. Additionally, infection in the first trimester of pregnancy is very harmful. Congenital toxoplasmosis presents with intracranial calcifications, classically. It can also present with hydrocephalus, microcephaly, blindness, petechiae. Siramycin is the drug of choice to try to prevent vertical transmission from mother to baby. It is typically gotten from cat faeces or raw/undercooked meat, not raw eggs (raw eggs: think salmonella).

The most probable diagnosis of this patient is Cotard syndrome with major depressive disorder.

Cotard syndrome is a rare mental disorder where the affected patient believes that they (or in some cases just a part of their body) is either dead or non-existent. This delusion is often difficult to treat and can result in significant problems due to patients stopping eating or drinking as they deem it not necessary. Cotard syndrome is often associated with severe depression and psychotic disorders (like schizophrenia).

Other delusional syndromes:
– Othello syndrome is a delusional belief that a patients partner is committing infidelity despite no evidence of this. It can often result in violence and controlling behaviour.
– De Clerambault syndrome (otherwise known as erotomania), is where a patient believes that a person of higher social or professional standing is in love with them. Often this presents with people who believe celebrities are in love with them.
– Capgras syndrome is characterised by a person believing their friend or relative had been replaced by an exact double.
– Couvade syndrome is also known as ‘sympathetic pregnancy’. It affects fathers, particularly during the first and third trimesters of pregnancy, who suffer the somatic features of pregnancy.
– Ekbom syndrome is also known as delusional parasitosis and is the belief that they are infected with parasites or have ‘bugs’ under their skin. This can vary from the classic psychosis symptoms in narcotic use where the user can ‘see’ bugs crawling under their skin or can be a patient who believes that they are infested with snakes.

Melanocytic naevi are skin tumours produced by melanocytes. They usually present in childhood but increase during puberty. The mnemonic A-B-C-D, is used by institutions to assess for suspicion of malignancy. The letters stand for asymmetry, border, colour, and diameter. If a mole starts changing in size, colour, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include if it begins to crust over, bleed, itch, or become inflamed.

Classic Kallmann syndrome (KS) is due to isolated hypogonadotropic hypogonadism. Most patients have gonadotropin-releasing hormone (GnRH) deficiency, as suggested by their response to pulsatile GnRH therapy. The hypothalamic-pituitary function is otherwise normal in most patients, and hypothalamic-pituitary imaging reveals no space-occupying lesions. By definition, either anosmia or severe hyposmia is present in patients with Kallmann syndrome.

The best treatment for the patient in question would be methylene blue.
The most probable diagnosis in this patient is methemoglobinemia due to the ingestion of amyl nitrate.

Amyl nitrate promotes the formation of methaemoglobin, which avidly conserves oxygen and leads to decreased tissue oxygen saturations.

Treatment of choice includes methylene blue and vitamin C.

Adverse effects:
Benign side effects include green or blue discoloration of urine and patients should be forewarned.
Significant side effects are based on methylene blue, itself, being an oxidizing agent and an inhibitor of monoamine oxidase A (MAO-A).
As an oxidizing agent, methylene blue can actually precipitate methemoglobinemia or haemolysis in high doses or when ineffectively reduced.
Methylene blue administration in a patient taking a serotonergic agents may predispose to serotonin syndrome.

Note: Although methylene blue administration is controversial in the setting of G6PD-deficiency due to reduced levels of NADPH, it is not contraindicated and should be administered cautiously and judiciously.

The human immunodeficiency virus (HIV) is grouped to the genus Lentivirus within the family of Retroviridae, subfamily Orthoretrovirinae. The HIV genome consists of two identical single-stranded RNA molecules that are enclosed within the core of the virus particle. The genome of the HIV provirus, also known as proviral DNA, is generated by the reverse transcription of the viral RNA genome into DNA, degradation of the RNA and integration of the double-stranded HIV DNA into the human genome.

When you have a patient with HIV and diarrhoea on the exam, think Cryptosporidium. In those who are immunocompetent this organism doesn’t usually cause symptoms, but in immunocompromised people like those with HIV, it causes infection and diarrhoea. Typically those with CD4 counts of <100 cells/µL1 have the greatest risk for prolonged, severe, or extraintestinal cryptosporidiosis.

This is a classic clinical presentation, with alcohol intake and nausea/vomiting that leads to hematemesis, of a Mallory-Weiss tear. In Mallory-Weiss tear, they typically present as a hemodynamically stable patient after a night of binge drinking and excessive resultant vomiting. Given his EGD did not show any other pathology and he is now stable, he can be discharged home.

The history is suggestive of scleroderma renal crisis, where we would expect thrombotic microangiopathy process with vascular endothelium involvement manifesting as mucoid intimal thickening or onion skin effect.

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.

Giant Cell Arteritis (Temporal Arteritis) is the most probable diagnosis. GCA should always be considered in the differential diagnosis of a new-onset headache in patients 50 years of age or older with an elevated erythrocyte sedimentation rate. Temporal artery biopsy remains the criterion standard for diagnosis of this granulomatous vasculitis. High-dose corticosteroid therapy is the universally accepted treatment.