This case is most likely RTA type II, due to decreased proximal bicarbonate reabsorption, which leads to metabolic acidosis, hypokalaemia, hyperchloremia, and <6 urine pH .

Mycoplasma infection causes cold autoimmune haemolytic anaemia (AIHA). The rest of the aforementioned options cause warm AIHA.

AIHA may be divided into ‘warm’ and ‘cold’ types, according to the temperature at which the antibodies best cause haemolysis. It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection, or drugs.

1. Warm AIHA:
In warm AIHA, the antibody (usually IgG) causes haemolysis best at body temperature and tends to occur in extravascular sites, for example, spleen. Management options include steroids, immunosuppression, and splenectomy. It is caused by autoimmune diseases such as SLE (rarely causes mixed-type AIHA), cancers such as lymphomas and CLL, and drugs such as methyldopa.

2. Cold AIHA:
The antibody in cold AIHA is usually IgM and causes haemolysis best at 4°C and occurs more commonly intravascularly. Features may include symptoms of Raynaud’s disease and acrocyanosis. Patients do not respond well to steroids. Cold AIHA is caused by cancers such as lymphomas, and infections such as mycoplasma and EBV.

Lysosomal hydrolases are synthesized in the rough endoplasmic reticulum and specifically transported through the Golgi apparatus to the trans-Golgi network, from which transport vesicles bud to deliver them to the endosomal/lysosomal compartment. The explanation of how the lysosomal enzymes are accurately recognized and selected over many other proteins in the trans-Golgi network relies on them being tagged with a unique marker: the mannose-6-phosphate (M6P) group, which is added exclusively to the N-linked oligosaccharides of lysosomal soluble hydrolases, as they pass through the cis-Golgi network. Generation of the M6P recognition marker depends on a reaction involving two different enzymes: UDP-N-acetylglucosamine 1-phosphotransferase and α-N-acetylglucosamine-1-phosphodiester α-N-acetylglucosaminidase.

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.

Tumour lysis syndrome (TLS) occurs most notably in patients with haematological malignancies including, Non-Hodgkin’s Lymphoma (NHL) and Acute Lymphocytic Leukaemia (ALL).
Risk factors for TLS include:
• Large tumour burden
• Sensitivity of the tumour to chemotherapy
• Rapid tumour growth rate
TLS is characterized by:
• Hyperuricemia
• Hyperkalaemia
• Hyperphosphatemia
• Hypocalcaemia
Treatment of TLS:
• Allopurinol: It is a xanthine oxidase inhibitor, it reduces the conversion of nucleic acid by-products to uric acid. Thus, it prevents urate nephropathy and subsequent oliguric renal failure. Note: dose reduction is essential in renal failure or if given along with mercaptopurine or azathioprine.
Alternatives to Allopurinol: Febuxostat; Rasburicase are useful in patients with hyperuricemia.
• Hydration
• Diuresis: Should be considered in well hydrated patients with insufficient urine output. Furosemide to be considered in normo-volemic patients with hyperkalaemia. Urine alkalization can be considered for promoting alkaline diuresis.
• Treatment of electrolyte imbalances including hyperkalaemia, hyperphosphatemia, and hypocalcaemia.
• Dialysis can be considered in refractory cases.

An overall concordance rate in monozygotic twins was documented to be 25% as compared to dizygotic twins with 3%. First degree relatives have a chance of around 3% of developing the disease. Caucasians show an increase frequency of HLA-B8. The Japanese lupus patients had a stronger association with HLA-DR2.

Pregnant patient in a third world country with hepatitis: The answer is most likely Hepatitis E. The mortality for Hepatitis E in pregnant women is very high. It is transmitted faecal-orally. There is no hepatitis G. Hepatitis C, B, A are less likely to be the correct answer than E given it’s classic association with pregnancy and poor living conditions.

Adult onset Still’s disease (AOSD) is an uncommon systemic inflammatory disease on the clinical spectrum of autoinflammatory disorders. Its presentation and clinical course may result in several well-differentiated phenotypes: from a systemic and highly symptomatic pattern to a chronic articular pattern. Overproduction of numerous pro-inflammatory cytokines is observed in AOSD. Anakinra, a human interleukin (IL)-1R antagonist, has recently been approved in the treatment of AOSD. Denosumab is a RANK ligand inhibitor used in the treatment of osteoporosis. Mepolizumab is used in the treatment of severe asthma with elevated eosinophils. There is some evidence to support the use of tocilizumab, an anti-IL6 monoclonal antibody in adult onset Still’s, but there is stronger data favouring the use of tocilizumab in the treatment of rheumatoid arthritis. Rituximab is usually reserved for patients who are unresponsive to anakinra.

The patient most likely has Klinefelter’s syndrome.
Klinefelter syndrome (KS) refers to a group of chromosomal disorders in which the normal male karyotype, 46,XY, has at least one extra X chromosome. XXY aneuploidy, the most common human sex chromosome disorder. It is also the most common chromosomal disorder associated with male hypogonadism and infertility.
Klinefelter syndrome is characterized by hypogonadism (micro-orchidism, oligospermia/azoospermia), gynecomastia in late puberty, hyalinization and fibrosis of the seminiferous tubules, elevated urinary gonadotropin levels, and behavioural concerns.

West Nile virus is an RNA virus transmitted by the Culex species of mosquitoes. It is mostly prevalent in South America, Africa and some parts of Europe. Clinically it presents with high grade fever, headache, abdominal pain, anorexia and a morbilliform rash over the body. It can also lead to meningitis, encephalitis and flaccid paralysis by affecting the anterior horn cells, a process suggesting similarity to poliomyelitis. It can be fatal if not treated abruptly. Studies suggest that it can be transferred from mother to offspring. New-borns may present with encephalitis, chorioretinitis and wide spread brain damage. Patients suffering from West Nile virus can be effectively treated with interferon, IV immunoglobulin and Ribavirin.