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Biomedical subjects

T W L Mak

Publications and source records attributed to T W L Mak.

7 recordsLinked to original sources
PubMed2006

Very long-chain acyl-CoA dehydrogenase deficiency presenting as acute hypercapnic respiratory failure.

Very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) is a key enzyme catalysing the dehydrogenation of long-chain fatty acids in mitochondrial beta-oxidation. VLCAD deficiency is a genetic disorder that commonly presents in infancy or childhood with episodes of hypoketotic hypoglycaemia, cardiomyopathy and liver dysfunction. The present study reports an 18-yr-old Chinese female who presented with acute hypercapnic respiratory failure and rhabdomyolysis after a period of prolonged fasting and exertion. VLCAD deficiency was confirmed with decreased VLCAD activity in cultured fibroblasts. The patient completely recovered with supportive care. Pulmonary function tests after the acute episode showed evidence of chronic subclinical respiratory muscle weakness. In conclusion, this rare metabolic disorder should be considered in patients presenting with unexplained acute respiratory paralysis and failure.

Acyl-CoA Dehydrogenase, Long-Chain↗
PubMed2006

Drug-induced hypoglycaemia--new insight into an old problem.

OBJECTIVE: To review the causes of drug-induced hypoglycaemia in patients not taking hypoglycaemic medications. DESIGN: Retrospective study. SETTING: Regional hospitals in Hong Kong. PATIENTS: Patients with suspected drug-induced hypoglycaemia without a known history of exposure to hypoglycaemic agents, referred to the Hospital Authority Toxicology Reference Laboratory from June 2005 to March 2006 inclusive. MAIN OUTCOME MEASURES: Rate of positive cases, laboratory findings, possible causes, age distribution, and final outcomes. RESULTS: A total of 51 such patients were referred, in whom the presence of oral hypoglycaemic agents was detected (or inferred) in 23 (45%). In 12 of the 23 patients, oral hypoglycaemic agents could only be detected by target analysis, not through broad-spectrum screening. Gliclazide and glibenclamide were detected in 14 and eight patients respectively, whereas glimepiride, nateglinide and rosiglitazone were detected in the remaining patient. Possible sources of oral hypoglycaemic agents included drug administration errors in residential care homes for the elderly (n=9), mistakenly taking medication of a family member or employer (n=6), taking stock medication by mistake (n=2), taking Chinese proprietary medicine adulterated with oral hypoglycaemic agents (n=1), taking unknown pills bought from a retail pharmacy (n=1), and unknown (n=4). Regarding these 23 patients, 17 (74%) were aged 70 years or above and 21 (91%) recovered uneventfully. CONCLUSION: Hypoglycaemia due to inadvertent use of oral hypoglycaemic agents is a recognised problem, particularly in cases where family members living in the same household are taking similar medications. Possible drug administration errors in residential care homes for the elderly should be investigated, and procedures rectified if confirmed. Health care providers should be vigilant to such potential errors, especially in cases of unexplained hypoglycaemia.

Adult↗
PubMed2006

Aconite poisoning in camouflage.

The Toxicology Reference Laboratory has confirmed 10 cases of aconite poisoning from March 2004 to May 2006. In four of these 10 cases, the aconite herb was not listed in the written prescription. We report these four cases to highlight the problem of 'hidden' aconite poisoning.

Aconitum↗
PubMed2004

Formate buffer as preservative for urinary free catecholamine measurement.

BACKGROUND: Strong mineral acid is the most commonly used preservative for measuring urinary free catecholamines. Leakage of corrosive acid is a safety hazard. The use of formate buffer as a safer alternative was studied. METHODS: Twenty-two urine specimens from post-operative patients were collected and preserved in 0.5 M hydrochloric acid or 0.75 M formate buffer. The specimens were stored at 4 degrees C or -70 degrees C, respectively. The free catecholamine content was measured at regular intervals by high-performance liquid chromatography for 6 months. RESULTS: The preservation capability of formate buffer was equivalent to that of hydrochloric acid. Deep-freeze storage offered additional protection independent of the preservative used. CONCLUSION: The results of this study demonstrate that formate buffer, compared to the most popularly used strong mineral acid solution, is an equally effective preservation for urinary free catecholamines. The less acidic nature of formate should invite fewer unpleasant incidents and safety hazards.

Buffers↗
PubMed2004

Use of hair analysis in the diagnosis of heavy metal poisoning: report of three cases.

We report three paediatric cases of suspected heavy metal poisoning that presented with non-specific symptoms. Hair samples of the three patients were sent overseas for analysis; results showed abnormal levels of many elements, including some heavy metals. A diagnosis of heavy metal poisoning was made and chelation therapy was offered to each patient. Blood levels for some heavy metals were subsequently checked and all were within the normal range. The original diagnosis of heavy metal poisoning was therefore not substantiated. The patients did not have a history of exposure to heavy metals or specific clinical features of heavy metal poisoning. The non-invasive nature of hair analysis is tempting, but the validity of such testing in diagnosing heavy metal poisoning is questionable.

Chelation Therapy↗
PubMed2003

Macroprolactin-a cause of pseudohyperprolactinaemia.

Macroprolactin is a complex of immunoglobulin G and monomeric prolactin with little biological activity in vivo. Macroprolactin cross-reacts in modern commercial prolactin assays, however, leading to pseudohyperprolactinaemia. This report is of three patients with macroprolactinaemia and the untoward consequences if this benign condition is misdiagnosed as genuine hyperprolactinaemia are discussed. One adult and one child without symptoms of hyperprolactinaemia were incidentally found to have elevated serum prolactin levels, one of whom had a pituitary incidentaloma. Repeat prolactin measurement after polyethylene glycol precipitation showed that the majority of circulating prolactin was macroprolactin. The third patient had galactorrhoea and pituitary microadenoma. Polyethylene glycol study showed that macroprolactinaemia exists simultaneously with genuine hyperprolactinaemia leading to falsely high serum prolactin levels. The recognition of this relatively common and benign condition is important in order to avoid misdiagnosis and unnecessary investigations and treatment. Particular attention must be paid to patients in whom the clinical and radiological findings are incompatible.

Adult↗