Myotonic dystrophy is the most likely diagnosis here.
It is a multisystem disorder causing cognitive impairment, cataracts, cardiac problems and testicular atrophy, as well as affecting the muscles. Patients have muscle weakness, normally worse distally, and/or myotonia (which is worse in cold weather).
On examination, patients may also have frontal balding, a myopathic facies, bilateral ptosis, an ophthalmoplegia and wasting of facial muscles and other limb muscles. Myotonic dystrophy is associated with diabetes mellitus and pituitary dysfunction.
Diagnosis is normally based on clinical features with a characteristic electromyogram (EMG) of myotonic discharges. Creatine kinase is generally normal and muscle biopsy is non-specific.

Tuberculous lymphadenitis is a chronic, specific granulomatous inflammation of the lymph node with caseation necrosis, caused by infection with Mycobacterium tuberculosis or a related bacteria. The characteristic morphological element is the tuberculous granuloma (caseating tubercle).

The patient most likely suffers from Paget’s disease of the bone as his radiological examination shows both osteolytic and osteosclerotic lesions. Any bone or bones can be affected, but Paget’s disease occurs most frequently in the pelvis > lumbar spine > femur > thoracic spine > sacrum > skull > tibia.

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.

Tinea manum is a superficial fungal infection of the hands characterised by dry scaly rash and also involves the interdigital spaces of the hands.

Tinea pedis is a fungal infection of feet, whereas onychomycosis represents a fungal infection of the nails, characterised by nail dystrophy, hyperkeratosis.

Kerion is the name given to secondarily infected tinea capitis leading to a soft boggy swelling over the scalp.

Psoriasis presents as silvery scales over the extensors of the body and it may involve the nails, scalp and joints.

Primary amyloidosis is characterised by abnormal protein build-up in the tissues and organ such as the heart, liver, spleen, kidneys, skin, ligaments, and nerves. However, the most common cause of death in patients with primary amyloidosis is heart failure.

Squamous-cell carcinoma is the most common histological type of lung cancer to cavitate (82% of cavitary primary lung cancer), followed by adenocarcinoma and large cell carcinoma. Multiple cavitary lesions in primary lung cancer are rare, however, multifocal bronchoalveolar cell carcinoma can occasionally have multiple cavitary lesions. Small cell carcinoma is not known to cavitate.

Because of the patient’s history of chronic analgesic use of daily paracetamol intake, the most likely diagnosis of this case is Analgesic misuse headache. In these cases, the headache is only temporarily relieved by analgesics. Treatment involves gradual withdrawal of analgesics.

The major delayed problem with radiotherapy is the development of secondary cancers. This risk begins to appear ten years after therapy.

The history is suggestive of leptospirosis. This is a zoonotic infection caused by a spirochete. As the patient is in shock, resuscitation with IV fluids is the first step in the management. IV antibiotics should be started (Doxycycline or Penicillin) as soon as possible. Other investigations mentioned are important during the management to rule out other possible diagnoses.

Mumps presents with a prodromal phase of general malaise and fever. On examination there is usually painful parotid swelling which has high chances of becoming bilateral. In OM with effusion there are no signs of infection and the only symptom is usually hearing loss. Acute otitis externa produces otalgia as well as ear discharge and itching. Acute OM produces otalgia and specific findings upon otoscopy. In acute mastoiditis the patient experiences ear discharge, otalgia, headache, hearing loss and other general signs of inflammation.

Generalized Anxiety Disorder (GAD) is characterized by persistent and excessive worry about a number of different things. People with GAD may anticipate disaster and may be overly concerned about money, health, family, work, or other issues. Individuals with GAD find it difficult to control their worry. They may worry more than seems warranted about actual events or may expect the worst even when there is no apparent reason for concern.

GAD is diagnosed when a person finds it difficult to control worry on more days than not for at least six months and has three or more symptoms.

Treatment usually consists of a combination of pharmacotherapy and/or psychotherapy. Antidepressant agents are the drugs of choice in the treatment of anxiety disorders, particularly the newer agents, which have a safer adverse effect profile and higher ease of use than the older tricyclic antidepressants (TCAs), such as selective serotonin reuptake inhibitors (SSRIs).

Osteoblastic (or sclerotic) bony metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma. The other cancers listed in the options are osteolytic.

The somatostatin-secreting D-cells comprise ,5% of the cells of the pancreatic islets. The D-cells have a complex morphology and may, via cellular process, interact with many more islet cells than suggested by their low number. D-cells are equipped with ATP-sensitive potassium channels (KATP channels).

Androgen insensitivity syndrome (AIS), previously referred to as testicular feminization, is an X-linked disorder in which the patients are genotypically male (possessing and X and Y chromosome) and phenotypically female. This disorder is rare, with reported incidences from 1 in 20,000 to 1 in 60,000 live male births, and is the result of a missing gene on the X chromosome that is responsible for the cytoplasmic or nuclear testosterone receptor. In its absence, the gonad, which is a testis, produces normal amounts of testosterone; however, the end tissues are unable to respond due to the deficient receptors leading to the external genitalia developing in a female fashion. Anti-mullerian hormone, which is produced by the testis, is normal in these patients, leading to regression of the Mullerian duct. Wolffian duct development, which depends on testosterone, does not occur as the ducts lack the receptors.
The cumulative effect is a genotypic male with normal external female genitalia (without pubic or axillary hair), no menses, normal breast development, short or absent vagina, no internal sex organs, and the presence of testis. Frequently, these patients have bilateral inguinal hernias in childhood, and their presence should arouse suspicion of the diagnosis.

This patient has Klumpke’s paralysis due to damage to the T1 nerve root. This root eventually supplies the median and ulnar nerves. The ulnar nerve supplies all of the intrinsic hand muscles except for those of the thenar eminence and the first and second lumbricals, which are innervated by the median nerve.

Statins are a selective, competitive inhibitor of hydroxymethylglutaryl-CoA (HMG-CoA) reductase, which is the enzyme responsible for the conversion of HMG-CoA to mevalonate in the cholesterol synthesis pathway.
Statins are usually well tolerated with myopathy, rhabdomyolysis, hepatotoxicity, and diabetes mellitus being the most common adverse reactions.
This is the rate-limiting step in cholesterol synthesis, that leads to increased hepatic low-density lipoprotein (LDL) receptors and reduced hepatic VLDL synthesis coupled with increased very-low-density lipoprotein (VLDL) clearance.

The diagnosis for the aforementioned case is thrombotic thrombocytopenic purpura (TTP). TTP is classically characterised as a pentad of thrombocytopaenia, microvascular haemolysis, fluctuating neurological signs, renal impairment, and fever.

The differential diagnosis for severe thrombocytopaenia is immune thrombocytopenic purpura (ITP). ITP is more common than TTP. However, a patient of ITP would not present with the range of symptoms seen in this scenario.

In TTP, there is deficiency of a protease which breaks down large multimers of von Willebrand factor. This leads to abnormally large and sticky multimers of von Willebrand factor which cause platelets to clump within the vessels.

Untreated TTP has a mortality rate of up to 90%. Therefore, rapid plasma exchange (PEX) may be a life-saving intervention. Platelet transfusion in TTP is only indicated if there is an ongoing life-threatening bleed. Intravenous methylprednisolone is indicated after treatment with PEX has been completed. There is no current role of intravenous immunoglobulin in the routine management of TTP. However, there have been reports of its successful use in PEX- and steroid-refractory cases. Intravenous argatroban is indicated in heparin-induced thrombocytopaenia (HIT), but there is no history of recent heparin administration or hospitalisation in this patient nor are the clinical signs consistent with HIT.

Management options for TTP include PEX as the treatment of choice. Steroids and immunosuppressants are also given. Antibiotics are not recommended as they may worsen the outcome of the disease. For cases resistant to PEX and pharmacologic therapy, vincristine is given.

1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.

Beckwith-Wiedemann syndrome is a inherited condition associated with organomegaly, macroglossia, abdominal wall defects, Wilm’s tumour and neonatal hypoglycaemia. Wilm’s tumour is a kidney cancer that usually occurs in children. The causes are unknown, however, risk factors include race and family history. Of note, Wilm’s tumour can occur as part of the following syndromes: WAGR syndrome, Denys-Drash syndrome, and Beckwith-Wiedmann syndrome and not the other listed options in this question.