Acute hypothermia in Covid 19: A case report

Dear Editor,

In December 2019, a cluster of pneumonia was reported in Wuhan, Hubei China for the first time [1]. A corona virus was identified as the pathogen – SARS Cov 2 and the disease it caused called Covid 19. The disease emerged in China and spread rapidly throughout the world.

A recent meta-analysis of clinical, laboratory and imaging features of Covid 19 described fever, cough and myalgia as the most common clinical features. Regarding the laboratory findings, lymphopenia was the more frequent sign, followed by the high C-reactive protein [2].

This article highlights a case of confirmed Covid 19 infection with initial hypothermia, which has not been reported so far as a revealing feature of the disease.

A 62-year-old man of black African origin, was hospitalised in our department for epileptic seizures. He had a medical history of arterial hypertension, ischaemic cardiopathy, mild thrombopenia, ischaemic and haemorrhagic strokes responsible for mild vascular dementia.

At the time of admission, blood test revealed a neutropenia without lymphopenia, and a normal C reactive protein level. He had a normal mental status. A myelogram was performed and did not show any abnormalities.

He then became lethargic and his mental status altered. Four days later his body temperature dropped and was controlled at 30,2°(intrarectal) without any respiratory signs being reported (no polypnea, no cough).

The brain MRI revealed no additional abnormality and the electroencephalography was not suggestive of nonconvulsive status epilepticus.

The blood test revealed a lymphopenia (0.82G/L), thrombopenia (54G/L), elevated C reactive protein (48 mg/L). The procalcitonin was negative (0.15 ng/L) and blood cultures were negative.

A thoracic CT scan revealed bilateral consolidation, ground glass opacities and pleural effusions.

The diagnosis of SARS Cov 2 was confirmed by RT-PCR on a nasopharyngeal swab.

The patient's clinical condition worsened in the following days, and death occurred 7 days after the hypothermic episode.

Fever was never present at no stage throughout the illness.

The initial clinical presentation of Covid 19 was a respiratory tract infection and the most common symptoms are fever, cough and fatigue. In the severe cases, patients may develop pneumonia, acute respiratory distress syndrome, acute cardiac dysfunction, and multi-organ failure. Central nervous system manifestations of Covid 19 have now been described [3]. As in other corona virus infections, the main neurological manifestations are convulsion, febrile seizure, encephalitis, encephalomyelitis and the recently reported anosmia/aguesia. [4,5]

Our patient's first symptoms were solely lethargy and hypothermia, without any other manifestation.

Hypothermia is defined as a drop in body temperature below 35 °C. Acute causes of hypothermia include accidental hypothermia due to exposure to cold weather or cold water immersion. Other causes of hypothermia can be metabolic, drugs, sepsis, and lesions in the posterior part of the hypothalamus.

In our case, the physiopathology of hypothermia is unclear. It could have been a specific brain lesion in the hypothalamus or brainstem, which was not visible on brain MRI, as neurological complication have been described in SARS Cov 2 infection. However, the mechanism and the route taken by the virus to reach the central nervous system is not yet well understood. The capacity of the human corona virus to reach the central nervous system after the nasal infection was described by St Jean in mice in 2004 [6], who reported that upon infection, viral antigens are detected in the olfactory bulb 3 days later, with no presence of virus in perivascular blood cells or any other part of the brain.

It could also be a systemic inflammatory response (as in sepsis cases), where fever is usually present. However, in about 10% of the patients with sepsis, hypothermia instead of hyperthermia can be observed with the same elevated inflammatory cytokines. Here again neither the mechanism, nor the usefulness of the reaction, is yet truly understood. In our case we have no argument for a sepsis, nor for bacterial infection. Indeed, blood cultures and procalcitonin were negative.

In our patient the nasal infection occurred without any typical symptoms of Covid 19.

When the lethargy and hypothermia first occurred, we were looking for a sepsis or stroke, and eliminated an epileptic status. We found no evidence for a drug related or metabolic cause of hypothermia. The presence of the lymphopenia associated with an elevated C reaction protein, and the chest CT characteristics suggested infection with SARS Cov 2, which was then confirmed by the RT-PCR.

Here, we report the case of a patient with Covid-19 disease with atypical features characterized by hypothermia and lethargy. We suggest to give special attention to very low temperatures during the SARS CoV2 pandemic.

Declaration of Competing Interest

None.